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November 17, 2020
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https://www.sciencedaily.com/releases/2020/11/201117122838.htm
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Holes in Greenland ice sheet are larger than previously thought
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Holes that carry surface meltwater to the base of the Greenland ice sheet, called moulins, are much larger than previously thought, according to a new study based on observation and first-hand exploration by a team including a geologist from the University of Arkansas.
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The extra volume could influence the stability of the Greenland ice sheet and how quickly it slides toward the sea.The team studied the relationship between the size of the moulins and the daily variation of water depth in them during the summer melt season. Scientists believe increased water depth, and therefore pressure, inside moulins lubricates the base of the ice sheet and increases the speed of its movement toward the sea, the way an ice cube slides easily on a thin film of water. But until now, little was known about the actual size of moulins and how much water they can hold."We compared our models with in-the-field observations of the water levels and it seemed like we would need really huge volumes inside moulins to produce the relatively smaller water variations that we were seeing," said Matt Covington, associate professor of geosciences and first author of the study published in the journal Geophysical Research Letters. "Then when we went back in the following year and explored a moulin, it was giant. It was a case where the model made the prediction, and we went out in the field and it turned out to be right."The team made two trips to the Greenland ice sheet in October 2018 and October 2019. During each trip, they used ropes and other climbing equipment to rappel 100 meters into two separate moulins, almost reaching the water level."It's intimidating," said Covington, an experienced cave explorer. "You back over the edge and you just see blueish ice going down as far as you can see, and then it's blackness and there also are occasional sounds of crashing ice, which is pretty unnerving."Scientists have long observed that Greenland's ice sheet moves and theorized that warmer summer melt seasons due to climate change could speed up that movement. But researchers have little data to help them understand the interaction between meltwater and the base of the ice sheet. The team's findings add to the knowledge of how water interacts with the base of the ice sheet."We're trying to understand the way the meltwater is interacting with the ice motion, and the main thing that we found is that the water pressure within these moulins is not as variable as was previously observed, and that this seems to result from really large volumes in the moulins," Covington said.
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Climate
| 2,020 |
November 17, 2020
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https://www.sciencedaily.com/releases/2020/11/201117113046.htm
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In retrospect, the burning of wood in district heating plants has resulted in climate saving
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A new report from the University of Copenhagen shows that the burning of wood is significantly more climate friendly than coal and slightly more climate friendly than natural gas over the long run. For the first time, researchers quantified what the conversion of 10 Danish cogeneration plants from coal or natural gas to biomass has meant for their greenhouse gas emissions.
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Energy production is responsible for a large part of Danish greenhouse gas emissions. In 2018, more than 20 percent of greenhouse gas emissions were released as a result of heat and electricity production (9.4 out of 48 million tonnes of COA conversion to wood biomass (wood chips and pellets) by Danish district heating plants has benefited the climate and is the more climate-friendly option compared to coal and natural gas. These are the findings of a new report from the University of Copenhagen's Department of Geosciences and Natural Resource Management.The study is the first retrospective investigation by researchers of what a conversion to wood biomass has meant for greenhouse gas emissions at ten Danish cogeneration plants -- and thereby the climate impact of replacing either coal or natural gas in favour of wood biomass.Among other things, researchers calculated the so-called carbon payback period for each plant, i.e. how long it takes for the conversion to wood biomass to elicit a positive climate effect."Our results demonstrate that the transition from coal to wood biomass has had a positive effect on COThe researchers also looked at the total COTransitioning from coal to biomass resulted in a 15 to 71 percent reduction in COThe fact that, in one case, emissions were -4 percent after 30 years as a result of the conversion, is partly due to the fact that, in relation to energy content, burning natural gas emits less CO"When such large fluctuations in the figures occur, it is because the payback period and the amount of COThe 10 Danish cogeneration plants collected 32 percent of their wood biomass from Danish forests, while 41 percent was sourced from the Baltic states, seven percent from Russia and Belarus, and seven percent from the United States. The type of wood biomass used and the distance it needed to be transported factored into the carbon budget as well, according to Professor Bentsen."For the typical plant that was once coal-fired, but now using wood from around Denmark and only uses forestry residue that cannot be used for other products, the payback period was roughly one year. The 30-year saving was as much as 60%," explains Niclas Scott Bentsen.Wood has an enormous potential to displace carbon heavy construction materials such as steel and concrete and is therefore an important aspect of the green transition."Our study demonstrates that the extent to which wood is used for construction or other forms of production, where the long lifespan of wood can bind COThe method used in the study includes an analysis of time series from individual plants that includes the pre- and post-conversion period from fossil energy sources to wood biomass. Among other things, the analysis included specific knowledge of the type of fuel used, where the fuel came from and what alternative uses the wood might have had.Energy production is responsible for a large part of Danish greenhouse gas emissions. In 2018, more than 20 percent of greenhouse gas emissions were released as a result of heat and electricity production (9.4 out of 48 million tonnes of COOf Denmark's total energy consumption, 16 percent of energy is generated from the burning of wood biomass. By comparison, 7 percent of energy consumption comes from wind turbines.To reduce the carbon recovery period and atmospheric COThe project is funded by Danish Energy and the Danish District Heating Association. The project was followed by a follow-up group consisting of representatives from the Council for Green Conversion, the Danish Society for Nature Conservation, Concito and the Danish Energy Agency. The report is peer reviewed by internationally renowned researchers.
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Climate
| 2,020 |
November 16, 2020
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https://www.sciencedaily.com/releases/2020/11/201116161218.htm
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Researchers quantify carbon changes in Sierra Nevada meadow soils
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Meadows in the Sierra Nevada mountains are critical components of watersheds. In addition to supplying water to over 25 million people in California and Nevada, meadows contain large quantities of carbon belowground. While it has been known for some time that meadows have large quantities of soil carbon, whether meadow soils are gaining or losing carbon has remained unclear.
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A new study led by researchers in the College of Agriculture, Biotechnology & Natural Resources at the University of Nevada, Reno, has demonstrated for the first time that meadows throughout the region are both gaining and losing carbon at high rates. Capture and storage of carbon in soil is a natural way to reduce carbon dioxide levels in the atmosphere and combat climate change. However, human activities can disrupt natural processes and lead to the loss of soil carbon to the atmosphere. These results suggest that meadow management may either contribute to climate change or mitigate the harmful effects of increasing atmospheric carbon dioxide.The research was conducted in partnership with the University of California Merced, as well as numerous restoration practitioners and conservation organizations in more than a dozen meadows throughout the Sierra Nevada mountains. The study is aimed at arming restoration practitioners with information to help make good management decisions."Meadows are known for their lush, diverse vegetation supported by soils that stay wet into the summer," explained University of Nevada, Reno, doctoral candidate Cody Reed, who led the study. "However, a long history of human activity in many meadows throughout the Sierra Nevada has resulted in drier soils and the replacement of wetland vegetation with sparse grasses and shrubs."In research published this week in the scientific journal In the long-term, such changes to the large soil carbon stocks in meadows could add up. And unlike in forests, where most carbon is sequestered in wood aboveground, the change in carbon in meadows is belowground. This means meadow soil carbon is less vulnerable to disturbances such as wildfire and may persist in the ecosystem for longer than aboveground carbon. At the same time, soil carbon provides other important benefits besides taking carbon out of the atmosphere."Worldwide, soils may contain up to four times as much carbon as the atmosphere," Reed explained. "Soil carbon in meadows also helps improve water quality and quantity, as well as soil fertility to support diverse plant communities important for wildlife and grazing."The research will likely help meadow restoration practitioners identify meadows in need of conservation to maintain soil carbon gains and meadows in need of restoration to prevent additional losses of soil carbon to the atmosphere. The researchers estimate that three acres of surrounding forest are required to offset the amount of carbon lost by one acre of degraded meadow. On the other hand, one acre of meadow may sequester as much carbon as six acres of forest."Our research shows meadows may be some of the best bang for the buck in terms of carbon management in the region," Sullivan said. "My hope is that soil carbon sequestration can be integrated with other objectives to achieve management strategies that improve ecosystem functions in meadows."Sullivan said he and his colleagues in the College's Department of Natural Resources & Environmental Science and Experiment Station plan to conduct future research to quantify the impacts of meadow restoration on soil carbon.
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Climate
| 2,020 |
November 16, 2020
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https://www.sciencedaily.com/releases/2020/11/201116125609.htm
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Implementing carbon pricing during the pandemic could help countries recover greener, smarter
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Countries across the globe have been struggling to deal with the impact of Covid-19 and its accompanying economic slowdown. As economies "build back better," it may be an opportune time to introduce carbon pricing to tackle climate change, according to new Princeton University policy research.
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While endorsed by many economists, carbon pricing has been slower to gain traction because of its potential to shock economies and the difficulty of securing political support for increasing taxes. However, fuel prices are already low and people are buying fewer goods and traveling less, so there could be greater benefits to introducing or strengthening carbon prices, the authors argue in the journal Carbon pricing -- whether in the form of taxes or emissions trading -- is an economic approach to account for the environmental costs of emitting greenhouse gases from burning fossil fuels. Carbon taxes typically apply to the producer with increased costs ultimately trickling down to any activity using carbon. For example, oil-extraction companies would be taxed, adding costs to any process that involved burning oil. Emissions-trading schemes set some cap on emissions and permits to emit are traded, but the number of total permits available correspond to that cap."When we think about long-term problems like the pandemic or climate change, it's easy to assume that the solutions could conflict since they all require massive resources," said lead author Kian Mintz-Woo, a former postdoctoral research associate in Princeton's University Center for Human Values and the Princeton School of Public and International Affairs (SPIA). "But what we describe in this article is how the context of the coronavirus crisis actually provides a unique opportunity for mutually reinforcing forward-thinking solutions to improve sustainability and wellbeing as countries recover."Mintz-Woo, who recently joined the Philosophy and Environmental Research Institute at University College Cork, Ireland, added that this research expands on an op-ed co-authored with Princeton Professor Peter Singer published on May 7 by Project Syndicate.With markets already reorienting to adjust to supply-and-demand shocks brought on by the pandemic, introducing carbon pricing now would result in marginally less disruption and could actually help drive greener economic activity. Placing a price on carbon could prompt industries to move away from more costly fossil-fuel intensive practices and toward long-term economic and environmental sustainability."Since carbon pollution already increases health and environmental costs borne by society, forcing those generating the costs to pay for them would lead to fairer production and consumption," Mintz-Woo said.In the context of low fuel prices over an extended period, as seen in recent months, the researchers suggest that a carbon tax could help stabilize prices and ensure that renewable energy sources -- the prices of which were becoming cost-competitive even before the Covid-19 crisis -- can remain competitive. The researchers say that as economies move toward recovery, a carbon price can drive individuals and firms to adopt less carbon-intensive processes, rather than locking-in unsustainable energy practices that will ultimately require more drastic future corrections."Preventing commitment to future emissions is the key," Mintz-Woo said. "But that cannot come at the expense of those who may be at risk for job losses in this transition. Governments should use the revenue to both reduce any regressive effects of the taxation and retrain those who come from industries that could be adversely affected."The researchers acknowledge that governments are under pressure to prioritize economic recovery from the Covid-19 crisis, so any policy changes with the potential to dampen a stimulus effect could be unpopular. However, they argue that high prices are not the primary obstacle to consumer purchasing; the cause of the economic slowdown has more to do with restricted market activity during the pandemic.Revenue generated from a carbon price could contribute toward government spending on social safety nets, fund other green priorities to drive innovation and new jobs, or be returned as credits to taxpayers. In all cases, the potential revenue source could be a welcome infusion during the Covid-19 crisis, when regional and national governments face massive fiscal shortfalls which can be expected to grow in the coming months."Right now, governments are considering bailouts for carbon-intensive sectors, like the airline industry," Mintz-Woo said. "While it's really hard on employees in that industry right now, government money would be far better spent on clean research and development investments and other strategies to help companies prepare for the future. And that means preparing for employment transitions away from carbon-intensive jobs and towards areas that will be more beneficial to the environment. Carbon pricing can help us do just that."The paper, "Carbon Pricing and COVID-19," first appeared in
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Climate
| 2,020 |
November 13, 2020
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https://www.sciencedaily.com/releases/2020/11/201113105833.htm
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What type of forest to choose for better CO2 storage?
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An international team led by the University of Geneva (UNIGE) has studied which types of forest, in terms of biodiversity, are the most effective in storing carbon. Inventory data from natural forests on five continents show that species diversity is optimal for equatorial and tropical rainforests, and that, conversely, in forests located in cold or dry regions, it is the abundance of trees and not their diversity that favours the recapture of CO
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In recent decades, researchers have suggested that species diversity allows for denser stacking and niche compartmentalisation that promotes the abundance of trees within a forest and that this abundance increases the forest's carbon storage capacity. But another hypothesis suggests that it is not diversity that allows tree abundance but the availability of energy substrate. Areas with higher energy content allows more trees to thrive per unit area and thus increase carbon recapture. While these two hypotheses question the scientific community on the relationship between diversity and abundance, knowing the answer could pragmatically guide the fight against CO"Having more species may not always be what is needed to achieve greater carbon storage in forests," states Dr. Madrigal-Gonzalez. Instead, this relation only seems to prevail in the most productive forest regions of the planet that are basically restricted to equatorial and tropical rain forests, and some temperate forests -- in regions where deforestation and human-induced forest fires have ravaged pristine environments lately. On the contrary, in the forests located in the coldest or driest regions on Earth, it is seemingly the abundance, promoted by productivity, that determines the diversity. Here, any increase in the number of species will not necessarily result in more trees and will not therefore have a big contribution to carbon storage. The findings of these studies are of substantial practical relevance as they will aid decision makers identifying nature-based climate change mitigation strategies and to successfully use forests and their sequestration of carbon to reach the climate goals defined in the Paris Agreement. "Increasing climatic stress in the most productive forests of the planet could diminish or even collapse the role of diversity against climate change" says Prof. Markus Stoffel, Professor at the Institute for Environmental Sciences of the UNIGE.
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Climate
| 2,020 |
November 12, 2020
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https://www.sciencedaily.com/releases/2020/11/201112144038.htm
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In a warming climate, can birds take the heat?
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We don't know precisely how hot things will get as climate change marches on, but there's reason to believe animals in the tropics may not fare as well as their temperate relatives. Many scientists think tropical animals, because they're accustomed to a more stable thermal environment, may be pushed beyond their limits quickly as temperatures soar. And that could lead to massive species loss.
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Yet, in a first-of-its-kind study, University of Illinois researchers show both temperate and tropical birds can handle acute heat stress much better than expected."In terms of their thermal physiology, a lot of these birds, including tropical species, can tolerate temperatures that are a lot higher than what they experience in their daily lives. That was surprising because tropical ectotherms, such as insects, have been shown to be extremely vulnerable to climate warming," says Henry Pollock, postdoctoral researcher at Illinois and first author on the study. "We're just not seeing the same things in birds. It is somewhat encouraging."Although they observed some promising trends, the researchers caution against celebrating too soon."It's not necessarily comforting news. If someone walked away from this thinking tropical birds are going to do fine because they're not going to overheat, that would be a simplistic bottom line to take away from this paper," says Jeff Brawn, professor in the Department of Natural Resources and Environmental Sciences at Illinois and co-author on the study. "Warming is likely to affect tropical birds indirectly, by impacting their resources, the structure of tropical forests. So they may not be flying around panting, suffering from heat exhaustion, but there may be more indirect effects."To test the assumption that tropical and temperate birds differ in their ability to cope with heat stress, Pollock brought 81 species from Panama and South Carolina into field labs to test their responses to rising temperatures. Using tiny sensors, he was able to detect internal body temperatures, as well as metabolic rates, when he exposed the birds to warmer and warmer environments.Species from both temperate and tropical zones handled the rising temperatures just fine. Birds from South Carolina had a higher heat tolerance, on average, than Panamanian birds, but both groups exceeded Pollock and Brawn's expectations. And among all the birds, doves and pigeons emerged as thermal superstars. Most birds cool down by panting, but doves and pigeons take advantage of their unique-among-birds ability to "sweat." In fact, Pollock says, they exceeded the limits of his testing equipment.Although the study provided the first-ever heat tolerance data for many bird species, the results take on more meaning when put into the context of warming projections."Both temperate and tropical birds were able to tolerate temperatures into the 40s [in degrees Celsius], but they only experience maximum temperatures of around 30 degrees Celsius in their everyday environments, so they have a substantial buffer," Pollock says.In other words, even if maximum air temperatures rise 3 to 4 degrees Celsius, as projected by some scientists, that's well within the thermal safety margins of all the birds Pollock measured.It's important to note the experiment, which measured acute heat stress, doesn't exactly replicate what's projected to happen during much more gradual climate warming. But few studies have examined the effects of chronic heat stress in birds, and having this baseline knowledge of their acute physiological limits is a good start."This is the first geographic comparison ever for birds. We need more data from more sites and studies of chronic heat stress over longer periods of time. But I think at the very least, what we can say is that they're able to tolerate higher temperatures than I think anybody expected," Pollock says.Brawn adds, "We're just starting to scratch the surface of what we need to do to really understand how climate change is going to affect birds. But this is an important first step."
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Climate
| 2,020 |
November 12, 2020
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https://www.sciencedaily.com/releases/2020/11/201112113118.htm
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Green Deal: Good for a climate-neutral Europe - bad for the planet
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Europe is to become the first climate-neutral continent by 2050 -- this goal of the "Green Deal" was announced by the EU in late 2019. Carbon emissions shall be reduced, while forestation, agriculture, environmentally friendly transport, recycling, and renewable energies shall be pushed. In
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The "Green Deal" adopted by the European Commission is to change European agriculture significantly in the next years and to contribute to making Europe the first climate-neutral continent. By 2030, about a quarter of all agricultural areas shall be farmed organically. Use of fertilizers and pesticides shall be reduced by 20 and 50 percent, respectively. In addition, the EU plans to plant 3 billion trees, to restore 25,000 km of rivers, and to reverse the decrease in populations of pollinators, such as bees or wasps. "These measures are important and reasonable," says Richard Fuchs from the Institute of Meteorology and Climate Research -- Atmospheric Environmental Research (IMK-IFU), KIT's Campus Alpine in Garmisch-Partenkirchen. "But it will be also necessary to specify foreign trade goals. Otherwise, we will only outsource the problem and continue to damage our planet." The research team compared sustainability conditions abroad with those in Europe and recommended actions for a standardized procedure.According to the study, the European Union annually imports millions of tons of agricultural products. In 2019, one fifth of crops were imported from abroad, as were many meat and dairy products. However, the imports come from countries, whose environmental legislations are far less stringent than those in Europe. For instance, genetically modified organisms have been subject to strong limitations in EU agriculture since 1999. Still, Europe imports genetically modified soy beans and corn from Brazil, Argentina, the USA, and Canada, the study reveals. "On the average, Europe's trading partners use more than twice as much fertilizers than we. Use of pesticides has also increased in most of these countries," Fuchs says. In his opinion, the problem is that each nation defines sustainability in a different way. Things forbidden in Europe might be permitted elsewhere. "By importing goods from these countries, the EU just outsources environmental damage to other regions and earns the laurels for its green policy at home," the climate researcher points out.The scientists of KIT recommend to urgently harmonize sustainability standards, to strongly reduce the use of fertilizers and pesticides and avoid deforestation. "The EU cannot impose its standards in other countries, but it can demand that goods entering the European market meet EU requirements," Richard Fuchs says.The researcher points out that Europe's COMoreover, the scientists promote reduction of consumption of meat and dairy products. This would reduce the import of agricultural products. Domestic production in accordance with adequate standards should be strengthened. For this purpose, areas with a low diversity of species or not used for agriculture so far could be converted. This would reduce deforestation in the tropics, which is mainly caused by the creation of new framing areas. Harvest yields might be increased by the CRISPR gene editing technology, the team says. This technology improves the edible mass, height, and pest resistance of plants without using genes of another species."Not all measures are easy to implement. Reorientation of agricultural production, however, would contribute to protecting Europe's food crops against global market fluctuations, disturbances of the supply chain, and some impactsd of climate change," Fuchs says. "Only then will the "Green Deal" be a good deal not only for a climate-neutral Europe, but also for our entire planet."
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Climate
| 2,020 |
November 12, 2020
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https://www.sciencedaily.com/releases/2020/11/201112113116.htm
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Applying environmental genomics to coral conservation
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Oceans are a bellwether for the planet's health, absorbing over 90% of the sun's energy. They demonstrate the extent to which rising temperatures are threatening coral reefs and other vital ecosystems that support biodiversity. In 2016 and 2017, an abrupt rise in surface temperatures in the Pacific Ocean caused mass bleaching on an unprecedented scale. Australia's Great Barrier Reef was especially hard-hit.
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Bleaching occurs when heat stress disrupts the symbiotic relationship between corals and the tiny algae that live inside them, providing a source of nutrients for coral and giving them their color. Persistent bleaching can lead to coral death. In the past two decades, abnormal heatwaves caused entire sections of reef off the coast of Australia -- measuring several kilometers in length -- to turn white.Scientists have already found that some reefs are better equipped to cope with recurring heat stress than others. For his thesis research, Oliver Selmoni, a doctoral assistant at EPFL's Laboratory of Geographic Information Systems (LASIG), applied the principles of environmental genomics to characterize this ability to adapt. Selmoni cross-referenced the results of genetic analyses of coral samples with ocean temperature data captured by satellites to determine what made some corals better able to withstand rising temperatures.Having applied his method to pre-existing data on a coral species in Japan, Selmoni travelled to New Caledonia to build a new study from the ground up. He collected his own coral samples with the help of the IRD scientists based in Nouméa. The findings were published in Nature The study aimed to test two hypotheses. The first is that coral populations learn to adapt to warmer seas after experiencing prolonged heat stress over many years. "The longer higher temperatures persist, the more likely it is that climate-resilient traits will develop and be passed down from generation to generation," explains Selmoni. The second hypothesis relates to connectivity: corals reproduce by releasing larvae into the water, which are then carried in ocean currents. "Corals rely on nearby populations for survival. When a reef is destroyed by environmental stressors or human activity, larvae from elsewhere are needed to kick-start repopulation," he adds.Selmoni's first task was to assess the composition of the marine environment in New Caledonia, using satellite data stretching back 30 years. After selecting 20 sites with the greatest temperature contrasts, he headed into the field to collect samples. "We focused on three flagship Pacific coral species that are susceptible to bleaching and relatively easy to find," he recalls. "It was a huge undertaking: 3,000 km by road and another 1,000 km by boat!" Selmoni shared details of his experience on the EPFL Out There blog.Using environmental genomics methods at LASIG, he found that the field observations supported his connectivity and adaptation hypotheses. "As expected, we observed a correlation between likelihood of adaptation and prolonged exposure to high heat stress. Conversely, corals in locations that had never experienced heat stress showed no climate-adaptive traits," explains Selmoni.Looking ahead, the maps developed in the study could be used to establish new marine protected areas (MPAs) -- zones where fishing, tourism, industry and other human activities are restricted -- in places where, through connectivity, heat-resistant coral strains could populate reefs around the archipelago. Another option could be to select and grow climate-adaptive corals, then transplant them into nearby reefs that are less able to withstand rising temperatures, thereby accelerating the process of natural selection. "Over time, these hardier strains can help rebuild damaged reefs or make existing coral populations more resilient to bleaching," adds Selmoni.
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Climate
| 2,020 |
November 12, 2020
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https://www.sciencedaily.com/releases/2020/11/201112080904.htm
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Possible 1,000-kilometer-long river running deep below Greenland's ice sheet
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Computational models suggest that melting water originating in the deep interior of Greenland could flow the entire length of a subglacial valley and exit at Petermann Fjord, along the northern coast of the island. Updating ice sheet models with this open valley could provide additional insight for future climate change predictions.
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Radar surveys have previously mapped Greenland's bedrock buried beneath two to three thousand meters of ice. Mathematical models were used to fill in the gaps in survey data and infer bedrock depths. The surveys revealed the long valley, but suggested it was segmented, preventing water from flowing freely through it. However, the peaks breaking the valley into segments only show up in areas where the mathematical modelling was used to fill in missing data, so could not be real.Christopher Chambers and Ralf Greve, scientists at Hokkaido University's Institute of Low Temperature Science, wanted to explore what might happen if the valley is open and melting increases at an area deep in Greenland's interior known for melting. Collaborating with researchers at the University of Oslo, they ran numerous simulations to compare water dynamics in northern Greenland with and without valley segmentation.The results, recently published in The "The results are consistent with a long subglacial river," Chambers says, "but considerable uncertainty remains. For example, we don't know how much water, if any, is available to flow along the valley, and if it does indeed exit at Petermann Fjord or is refrozen, or escapes the valley, along the way."If water is flowing, the model suggests it could traverse the whole length of the valley because the valley is relatively flat, similar to a riverbed. This suggests no parts of the ice sheet form a physical blockade. The simulations also suggested that there was more water flow towards the fjord with a level valley base set at 500 meters below sea level than when set at 100 meters below. In addition, when melting is increased only in the deep interior at a known region of basal melting, the simulated discharge is increased down the entire length of the valley only when the valley is unblocked. This suggests that a quite finely tuned relationship between the valley form and overlying ice can allow a very long down-valley water pathway to develop."Additional radar surveys are needed to confirm the simulations are accurate," says Greve, who has been developing the model used in the study, called Simulation Code for Polythermal Ice Sheets (SICOPOLIS). "This could introduce a fundamentally different hydrological system for the Greenland ice sheet. The correct simulation of such a long subglacial hydrological system could be important for accurate future ice sheet simulations under a changing climate."
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Climate
| 2,020 |
November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111180655.htm
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COVID-delayed Arctic research cruise yields late-season data
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Researchers studying the Bering and Chukchi seas for three weeks in October found no ice and a surprisingly active ecosystem as they added another year's data to a key climate change record.
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The research vessel Norseman II carried scientists from the University of Alaska Fairbanks, the University of Maryland Center for Environmental Science and Clark University.Maintaining the continuity of long-term observations is crucial as the region is affected by climate change. For example, the researchers collected sediments and small bottom-dwelling animals to help document harmful algal blooms that are becoming more common as Arctic waters warm. The blooms pose a threat to the humans and marine mammals that eat them.Because of pandemic-related delays, the cruise began on Oct. 2 -- a much later start than originally planned. Historically, the Bering and Chukchi sea ecosystem transitioned to lower-level activity as sea ice formed in October.This year, unseasonably warm ocean temperatures delayed sea ice formation by several weeks. The lack of ice likely allowed the greater biological activity observed by the researchers."The recovered data are already showing the effects of oceanic heat that extends further into the fall and early winter," said Seth Danielson of UAF's College of Fisheries and Ocean Sciences.The scientists collected data for several marine science programs monitoring the Pacific Arctic ecosystem.The Distributed Biological Observatory, led by Jacqueline Grebmeier of UMCES, has been sampling productive hot spots since the late 1980s in U.S. Arctic waters.The Arctic Marine Biodiversity Observing Network, led by Katrin Iken at UAF's College of Fisheries and Ocean Sciences, is part of a national network studying how biodiversity and species distributions are changing as a result of climate change in the U.S. Arctic.The researchers also visited the Chukchi Ecosystem Observatory, a set of highly instrumented oceanographic moorings that monitor the ecosystem year-round. "We only get one chance each year to deploy fresh sensors with new batteries, so this cruise was important to avoid interruptions to the observations," said Danielson, who leads the project."This was a really worthwhile effort that paid off in making biological data available from a part of the year where there have been historically few observations," said Grebmeier, the cruise's chief scientist.To protect communities in the Bering Strait from potential exposure to the COVID-19 virus, the team completed quarantines and multiple tests in Anchorage before the cruise. They traveled by chartered aircraft to Nome and were taken directly to the research vessel, bypassing the passenger terminal.Everyone aboard also adhered to COVID-19 health and safety mandates from their institutions and followed an isolation and travel plan in accordance with the Port of Nome and the State of Alaska.Funding for the cruise was provided by the National Oceanic and Atmospheric Administration, the North Pacific Research Board and the National Oceanic Partnership Program, which also includes funding by the Bureau of Ocean Energy Management.
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Climate
| 2,020 |
November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111144400.htm
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Tree rings may hold clues to impacts of distant supernovas on Earth
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Massive explosions of energy happening thousands of light-years from Earth may have left traces in our planet's biology and geology, according to new research by University of Colorado Boulder geoscientist Robert Brakenridge.
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The study, published this month in the "We see supernovas in other galaxies all the time," said Brakenridge, a senior research associate at the Institute of Arctic and Alpine Research (INSTAAR) at CU Boulder. "Through a telescope, a galaxy is a little misty spot. Then, all of a sudden, a star appears and may be as bright as the rest of the galaxy."A very nearby supernova could be capable of wiping human civilization off the face of the Earth. But even from farther away, these explosions may still take a toll, Brakenridge said, bathing our planet in dangerous radiation and damaging its protective ozone layer.To study those possible impacts, Brakenridge searched through the planet's tree ring records for the fingerprints of these distant, cosmic explosions. His findings suggest that relatively close supernovas could theoretically have triggered at least four disruptions to Earth's climate over the last 40,000 years.The results are far from conclusive, but they offer tantalizing hints that, when it comes to the stability of life on Earth, what happens in space doesn't always stay in space."These are extreme events, and their potential effects seem to match tree ring records," Brakenridge said.His research hinges on the case of a curious atom. Brakenridge explained that carbon-14, also known as radiocarbon, is a carbon isotope that occurs only in tiny amounts on Earth. It's not from around here, either. Radiocarbon is formed when cosmic rays from space bombard our planet's atmosphere on an almost constant basis."There's generally a steady amount year after year," Brakenridge said. "Trees pick up carbon dioxide and some of that carbon will be radiocarbon."Sometimes, however, the amount of radiocarbon that trees pick up isn't steady. Scientists have discovered a handful of cases in which the concentration of this isotope inside tree rings spikes -- suddenly and for no apparent earthly reason. Many scientists have hypothesized that these several-year-long spikes could be due to solar flares or huge ejections of energy from the surface of the sun.Brakenridge and a handful of other researchers have had their eye on events much farther from home."We're seeing terrestrial events that are begging for an explanation," Brakenridge said. "There are really only two possibilities: A solar flare or a supernova. I think the supernova hypothesis has been dismissed too quickly."He noted that scientists have recorded supernovas in other galaxies that have produced a stupendous amount of gamma radiation -- the same kind of radiation that can trigger the formation of radiocarbon atoms on Earth. While these isotopes aren't dangerous on their own, a spike in their levels could indicate that energy from a distant supernova has traveled hundreds to thousands of light-years to our planet.To test the hypothesis, Brakenridge turned to the past. He assembled a list of supernovas that occurred relatively close to Earth over the last 40,000 years. Scientists can study these events by observing the nebulas they left behind. He then compared the estimated ages of those galactic fireworks to the tree ring record on the ground.He found that of the eight closest supernovas studied, all seemed to be associated with unexplained spikes in the radiocarbon record on Earth. He considers four of these to be especially promising candidates. Take the case of a former star in the Vela constellation. This celestial body, which once sat about 815 lightyears from Earth, went supernova roughly 13,000 years ago. Not long after that, radiocarbon levels jumped up by nearly 3% on Earth -- a staggering increase.The findings aren't anywhere close to a smoking gun, or star, in this case. Scientists still have trouble dating past supernovas, making the timing of the Vela explosion uncertain with a possible error of as much as 1,500 years. It's also not clear what the impacts of such a disruption might have been for plants and animals on Earth at the time. But Brakenridge believes that the question is worth a lot more research."What keeps me going is when I look at the terrestrial record and I say, 'My God, the predicted and modeled effects do appear to be there.'"He hopes that humanity won't have to see those effects for itself anytime soon. Some astronomers think they've picked up signs that Betelgeuse, a red giant star in the constellation Orion, might be on the verge of collapsing and going supernova. And it's only 642.5 light-years from Earth, much closer than Vela."We can hope that's not what's about to happen because Betelgeuse is really close," he said.
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Climate
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November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111144356.htm
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Late-season Arctic research cruise reveals warm ocean temperatures, active ecosystem
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Arctic researchers Jacqueline Grebmeier and Lee Cooper have been visiting the Bering and Chukchi seas off Alaska for nearly 30 years, collecting information about the biological diversity of the watery world under the sea ice to understand how marine ecosystems are responding to environmental changes. This year, a late-season research cruise in October revealed a surprise. At a time of year when an ice-breaking ship is usually required to get them to some of the data-gathering outposts, scientists found nothing but open water and an unusually active ecosystem.
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"The water and air temperatures were warmer, and we had ecosystem activity that normally doesn't occur late in the season," said University of Maryland Center for Environmental Science Research Professor Jacqueline Grebmeier, chief scientist on the research cruise and a national and international leader in Arctic research.Grebmeier and Cooper were part of a small team of researchers from the University of Maryland Center for Environmental Science, the University of Alaska Fairbanks, and Clark University that completed an unusual late-season Arctic research cruise due travel challenges presented by COVID-19 pandemic. They found an ecosystem -- expected to be powering down to low-level winter activity with sea ice forming -- to be still active, likely due to unseasonably warm ocean temperatures. Sea ice formation was still a number of weeks away."2020 turned out to be the second lowest minimum sea ice extent, meaning that sea ice retreated back closer to the North Pole," Grebmeier said. "We had warming water up to 3 degrees Celsius higher than typical all the way through water column. That means you can't cool it down that quickly to build ice."And ice is important. It's the ice that sets up that really productive spring system to power the ecosystem."Without ice forming you don't get that spring ice algal production, which is the first hit of nice, fresh carbon that the animals in the sediments use to increase their growth," she said. "So some open water areas are going to bloom later in the season because it will be like opening a larger playing field and provide food for water column animals like zooplankton, while others that depended on that ice algal production in the bottom shallow shelf sediments are going to have more limited seasonal food."The late fall season sampling indicates that delays in sea ice formation are supporting late-season biological production that has not been commonly observed before."The biomass of microalgae in the water column was unexpectedly high and not much lower than often observed in the middle of the summer under near 24-hour daylight," said University of Maryland Center for Environmental Science Research Professor Lee Cooper, who led water column biological and chemical measurements.Grebmeier and Cooper are also seeing shifts in these benthic animals. The clams and worms that live on the bottom of the Arctic and are an important food source for everything from bottom-feeding fish to walruses and diving sea ducks."We are seeing declines in the biomass in a lot of areas so there isn't as much food on the sea floor as there used to be, meaning less food available for the things that we traditionally think of as Arctic animals," said Cooper. "The ecosystem is changing.""It's kind of like you took a balloon and you squeezed it, and the southern part of it is getting smaller and the northern part is getting bigger. There's a contraction of these rich Arctic fatty benthic animals from the south to higher amounts in the north," said Grebmeier.The researchers usually do their annual observations July-September, but the COVID-19 pandemic resulted in delays and pushed their cruise into October for the first time. Maintaining the continuity of long-term observations is crucial as the region is affected by climate change."We've been working up there for nearly 30 years annually. This would've been a gap in the measurements, and this was a critical year given the low ice extent," said Cooper. "We did the full suite of sampling we do in observing program, we just did it in October."The research vessel Norseman II carried the scientists for the three-week research cruise. Prior to the cruise, the science crew undertook a Covid-19 quarantine in Anchorage, including multiple testing, before flying to Nome and transferring directly to the ship to avoid any potential viral exposure to residents in the Bering Strait region. The individual participating universities had their own stringent requirements and testing protocols prior to approving travel.The team stopped at several established observing stations where scientists can monitor everything from the temperature and salinity of the water and the amount of zooplankton (fish food) swimming around to harmful algal blooms of phytoplankton and animals living in the sediment. The goal is to observe and document how the Arctic creatures are responding to climate change and track those ecosystem changes under further loss of sea ice.The Distributed Biological Observatory (DBO) is a series of standard stations occupied seasonally by national and international ships and moorings that take continuous physical, chemical and biological measurements in the U.S. Arctic waters to document how biological systems are changing and/or adapting as a result of environmental change. Grebmeier led an international team of scientists to establish the DBO in the North American Arctic.The Arctic Marine Biodiversity Observing Network, led by Katrin Iken at University of Alaska Fairbanks' College of Fisheries and Ocean Sciences, is part of a national network studying how biodiversity and species distributions are changing as a result of climate change in the U.S. Arctic.The researchers also visited the Chukchi Ecosystem Observatory, a set of highly instrumented oceanographic moorings that monitor the ecosystem year-round."This was a really worthwhile effort that paid off in making biological data available from a part of the year where there have been historically few observations," said Grebmeier.The samples obtained and brought back to home laboratories in Maryland, Washington State, and Alaska will support multiple long-term projects. The scientists were also able to collect samples for others who couldn't go on the cruise due to COVID travel and research restrictions.Funding for the cruise was provided by the National Oceanic and Atmospheric Administration, the North Pacific Research Board, and through the National Oceanic Partnership Program, which included funding from the Bureau of Ocean Energy Management.
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Climate
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November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111123945.htm
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Climate-adapted plant breeding
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The famous seed vault in Spitsbergen and national gene banks retain hundreds of thousands of seed samples to preserve old varieties of crop plants and the genetic diversity associated with them. Are these seed banks gold mines or seed cemeteries?
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Researchers around the globe are investigating whether retained samples contain genes that have been lost through breeding which could be beneficial in counteracting climate change. A research team led by Chris-Carolin Schön, Professor of Plant Breeding at the TUM, is now presenting a solution to harness the genetic potential of old varieties, so-called landraces.Since the 1960s, maize has been grown in Europe's fields mainly in the form of hybrid varieties. Hybrid varieties are developed through a specific breeding scheme and, for example are "trimmed" for high yield per hectare or low susceptibility to pests. In order to breed the best variety, a kit of characteristics is needed that could be relevant both today and in the future. Thus, genetic diversity is the basic prerequisite for breeding improved crop plants.Hybrid varieties, however, carry only a small selection of traits compared to old varieties, the landraces. The question then is whether in addition to undesirable traits, beneficial traits have been lost in the course of many breeding generations. Therefore, the call for landraces has recently been revived, as they are characterized by high biodiversity and are considered a natural source of new genetic variation for breeding. Genetic variation reflects different variants of a gene and can be recognized by differences in the plant's appearance.The early development of young plants is of particular importance in times of climate change. Drought and heat are the conditions most damaging to crops, such as maize, when they occur during flowering. When a plant can be cultivated early in the year because it can cope with cold, it has already left its flowering period behind when temperatures are particularly high in summer. This means that it is less damaged and yield losses can be avoided.Professor Schön and her colleagues have been examining landrace varieties for cold tolerance characteristics. For this purpose, they have developed a genome-based method of identifying and making targeted use of beneficial gene resources. After a preliminary study, in which the researchers identified the genetic differences of individual varieties, the researchers selected three landraces for cultivation in different locations with varying climatic conditions within Europe.The research team focused on traits related to early plant development and also took into account the stability of the plant (How well does it withstand wind?) and the growth form (straight or bushy?). Using molecular methods that scan the entire genome, they were able to link the data from the field trials to genes relevant to the specific traits."We have shown how to find new genetic variation for important traits in agricultural production. The variation in these traits is determined by many genes and is not sufficiently available in current breeding material," says Manfred Mayer, lead author of the study. "This opens the door to the development of improved climate-adapted hybrid varieties."
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Climate
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November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110133152.htm
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Large volcanic eruption caused the largest mass extinction
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Researchers in Japan, the US and China say they have found more concrete evidence of the volcanic cause of the largest mass extinction of life. Their research looked at two discrete eruption events: one that was previously unknown to researchers, and the other that resulted in large swaths of terrestrial and marine life going extinct.
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There have been five mass extinctions since the divergent evolution of early animals 450 -- 600 million years ago. The third was the largest one and is thought to have been triggered by the eruption of the Siberian Traps -- a large region of volcanic rock known as a large igneous province. But the correlation between the eruption and mass extinction has not yet been clarified.Sedimentary mercury enrichments, proxies for massive volcanic events, have been detected in dozens of sedimentary rocks from the end of the Permian. These rocks have been found deposited inland, in shallow seas and central oceans, but uncertainty remains as to their interpretation. Mercury can be sourced from either direct atmospheric deposition from volcanic emissions and riverine inputs from terrestrial organic matter oxidation when land/plant devastation -- referred to as terrestrial ecological disturbance -- occurs.The largest mass extinction occurred at the end of the Permian -- roughly 252 million years ago. This mass extinction was marked by the transition from the divergence of the Paleozoic reptiles and marine animals like brachiopods and trilobites to Mesozoic dinosaurs and marine animals such as mollusks. Approximately 90% of species disappeared at the end of the Permian.Current professor emeritus at Tohoku University, Kunio Kaiho led a team that looked into possible triggers of the largest mass extinction. They took sedimentary rock samples from two places -- southern China and Italy -- and analyzed the organic molecules and mercury (Hg) in them. They found two discrete coronene-Hg enrichments coinciding with the first terrestrial ecological disturbance and the following mass extinction in both areas."We believe this to be the product of large volcanic eruptions because the coronene anomaly was formed by abnormally high temperature combustion," says professor Kaiho. "High temperature magma or asteroid/comet impacts can make such a coronene enrichment.From the volcanic aspect, this could have occurred because of the higher temperature combustion of living and fossil organic matter from lava flows and horizontally intruded magma (sill) into the sedimentary coal and oil. The different magnitude of the two coronene-mercury enrichments shows that the terrestrial ecosystem was disrupted by smaller global environmental changes than the marine ecosystem. The duration between the two volcanic events is tens of thousands of years."Huge volcanic eruptions can produce sulfuric acid aerosols in the stratosphere and carbon dioxide in the atmosphere, which causes global climate changes. This rapid climate change is believed to be behind the loss of land and marine creatures.Coronene is a highly condensed six-ring polycyclic aromatic hydrocarbon, which requires significantly higher energy to form as compared to smaller PAHs. Therefore, high temperature volcanic combustion can cause the coronene enrichments. This means that high temperature combustion of hydrocarbons in the sedimentary rocks by lateral intrusion of magmas formed COKaiho's team is now studying other mass extinctions in the hopes of further understanding the cause and processes behind them.
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Climate
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November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110133145.htm
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Scientists have discovered an ancient lake bed deep beneath the Greenland ice
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Scientists have detected what they say are the sediments of a huge ancient lake bed sealed more than a mile under the ice of northwest Greenland -- the first-ever discovery of such a sub-glacial feature anywhere in the world. Apparently formed at a time when the area was ice-free but now completely frozen in, the lake bed may be hundreds of thousands or millions of years old, and contain unique fossil and chemical traces of past climates and life. Scientists consider such data vital to understanding what the Greenland ice sheet may do in coming years as climate warms, and thus the site makes a tantalizing target for drilling. A paper describing the discovery is in press at the journal
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"This could be an important repository of information, in a landscape that right now is totally concealed and inaccessible," said Guy Paxman, a postdoctoral researcher at Columbia University's Lamont-Doherty Earth Observatory and lead author of the report. "We're working to try and understand how the Greenland ice sheet has behaved in the past. It's important if we want to understand how it will behave in future decades." The ice sheet, which has been melting at an accelerating pace in recent years, contains enough water to raise global sea levels by about 24 feet.The researchers mapped out the lake bed by analyzing data from airborne geophysical instruments that can read signals that penetrate the ice and provide images of the geologic structures below. Most of the data came from aircraft flying at low altitude over the ice sheet as part of NASA's Operation IceBridge.The team says the basin once hosted a lake covering about 7,100 square kilometers (2,700 square miles), about the size of the U.S. states of Delaware and Rhode Island combined. Sediments in the basin, shaped vaguely like a meat cleaver, appear to range as much as 1.2 kilometers (three quarters of a mile) thick. The geophysical images show a network of at least 18 apparent onetime stream beds carved into the adjoining bedrock in a sloping escarpment to the north that must have fed the lake. The image also show at least one apparent outlet stream to the south. The researchers calculate that the water depth in the onetime lake ranged from about 50 meters to 250 meters (a maximum of about 800 feet).In recent years, scientists have found existing subglacial lakes in both Greenland and Antarctica, containing liquid water sandwiched in the ice, or between bedrock and ice. This is the first time anyone has spotted a fossil lake bed, apparently formed when there was no ice, and then later covered over and frozen in place. There is no evidence that the Greenland basin contains liquid water today.Paxman says there is no way to tell how old the lake bed is. Researchers say it is likely that ice has periodically advanced and retreated over much of Greenland for the last 10 million years, and maybe going back as far as 30 million years. A 2016 study led by Lamont-Doherty geochemist Joerg Schaefer has suggested that most of the Greenland ice may have melted for one or more extended periods some time in the last million years or so, but the details of that are sketchy. This particular area could have been repeatedly covered and uncovered, Paxman said, leaving a wide range of possibilities for the lake's history. In any case, Paxman says, the substantial depth of the sediments in the basin suggest that they must have built up during ice-free times over hundreds of thousands or millions of years."If we could get at those sediments, they could tell us when the ice was present or absent," he said.The researchers assembled a detailed picture of the lake basin and its surroundings by analyzing radar, gravity and magnetic data gathered by NASA. Ice-penetrating radar provided a basic topographic map of the earth' s surface underlying the ice. This revealed the outlines of the smooth, low-lying basin, nestled among higher-elevation rocks. Gravity measurements showed that the material in the basin is less dense than the surrounding hard, metamorphic rocks -- evidence that it is composed of sediments washed in from the sides. Measurements of magnetism (sediments are less magnetic than solid rock) helped the team map the depths of the sediments.The researchers say the basin may have formed along a now long-dormant fault line, when the bedrock stretched out and formed a low spot. Alternatively, but less likely, previous glaciations may have carved out the depression, leaving it to fill with water when the ice receded.What the sediments might contain is a mystery. Material washed out from the edges of the ice sheet have been found to contain the remains of pollen and other materials, suggesting that Greenland may have undergone warm periods during the last million years, allowing plants and maybe even forests to take hold. But the evidence is not conclusive, in part because it is hard to date such loose materials. The newly discovered lake bed, in contrast, could provide an intact archive of fossils and chemical signals dating to a so-far unknown distant past.The basin "may therefore be an important site for future sub-ice drilling and the recovery of sediment records that may yield valuable insights into the glacial, climatological and environmental history" of the region, the researchers write. With the top of the sediments lying 1.8 kilometers below the current ice surface (1.1 miles), such drilling would be daunting, but not impossible. In the 1990s, researchers penetrated almost 2 miles into the summit of the Greenland ice sheet and recovered several feet of bedrock -- at the time, the deepest ice core ever drilled. The feat, which took five years, has not since been repeated in Greenland, but a new project aimed at reaching shallower bedrock in another part of northwest Greenland is being planned for the next few years.The study was coauthored Jacqueline Austermann and Kirsty Tinto, both also based at Lamont-Doherty Earth Observatory. The research was supported by the U.S. National Science Foundation.
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Climate
| 2,020 |
November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201109152230.htm
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A better understanding of coral skeleton growth suggests ways to restore reefs
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Coral reefs are vibrant communities that host a quarter of all species in the ocean and are indirectly crucial to the survival of the rest. But they are slowly dying -- some estimates say 30 to 50 percent of reefs have been lost -- due to climate change.
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In a new study, University of Wisconsin-Madison physicists observed reef-forming corals at the nanoscale and identified how they create their skeletons. The results provide an explanation for how corals are resistant to acidifying oceans caused by rising carbon dioxide levels and suggest that controlling water temperature, not acidity, is crucial to mitigating loss and restoring reefs."Coral reefs are currently threatened by climate change. It's not in the future, it's in the present," says Pupa Gilbert, a physics professor at UW-Madison and senior author of the study. "How corals deposit their skeletons is fundamentally important to assess and help their survival."Reef-forming corals are marine animals that produce a hard skeleton made up of aragonite, one form of the mineral calcium carbonate. But how the skeletons grow has remained unclear. One model suggests that dissolved calcium and carbonate ions in the corals' calcifying fluid attach one at a time into the crystalline aragonite of the growing skeleton. A different model, proposed by Gilbert and colleagues in 2017 and based on a study of one species of coral, suggests instead that undissolved nanoparticles attach and then slowly crystallize.In the first part of a new study, published Nov. 9 in the PEEM results showed amorphous nanoparticles present in the coral tissue, at the growing surface, and in the region between the tissue and the skeleton, but never in the mature skeleton itself, supporting the nanoparticle attachment model. However, they also showed that while the growing edge is not densely packed with calcium carbonate, the mature skeleton is -- a result that does not support the nanoparticle attachment model."If you imagine a bunch of spheres, you can never fill space completely; there is always space in between spheres," Gilbert says. "So that was the first indication that nanoparticle attachment may not be the only method."The researchers next used a technique that measures the exposed internal surface area of porous materials. Large geologic crystals of aragonite or calcite -- formed by something not living -- are found to have around 100 times less surface area than the same amount of material made up of nanoparticles. When they applied this method to corals, their skeletons gave nearly the same value as large crystals, not nanoparticle materials."Corals fill space as much as a single crystal of calcite or aragonite. Thus, both ion attachment and particle attachment must occur," Gilbert says. "The two separate camps advocating for particles versus ions are actually both right."This new understanding of coral skeleton formation can only make sense if one more thing is true: that seawater is not in direct contact with the growing skeleton, as has been commonly assumed. In fact, recent studies of the coral calcifying fluid found that it contains slightly higher concentrations of calcium and three times more bicarbonate ions than seawater does, supporting the idea that the growing skeleton is indeed isolated from seawater.Instead, the researchers propose a model where the corals pump calcium and carbonate ions from seawater through coral tissue, which concentrates those minerals near the skeleton. Importantly, this control allows corals to regulate their internal ion concentrations, even as oceans acidify due to rising carbon dioxide levels."Up until this work, people had assumed that there was contact between seawater and the growing skeleton. We demonstrated that the skeleton is completely separate from seawater, and this has immediate consequences," Gilbert says. "If there are to be coral reef remediation strategies, they should not focus on countering ocean acidification, they should focus on countering ocean warming. To save coral reefs we should lower the temperature, not increase water pH."Support for this study comes from the U.S. Department of Energy (DE-FG02-07ER15899), the National Science Foundation (DMR-1603192), and the European Research Council (grant agreement No 755876). Spectromicroscopy experiments were done at the Advanced Light Source which is supported by the U.S. Department of Energy (Contract No. DE-AC02-05CH11231).
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Climate
| 2,020 |
November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201109110223.htm
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A jigsaw puzzle made of ancient dust
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From a South Pacific expedition, a research team led by geoscientist Dr Torben Struve brought back a research object which had travelled far before and can help explain the severe Earth cooling of the last Ice Age -- dust.
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During the last Ice Age about 20,000 years ago, iron-containing dust acted as a fertilizer for marine phytoplankton in the South Pacific, promoting COThe research team found that a large part of the dust deposited in the southern South Pacific at that time had travelled an extremely long way. Up to 80 percent of the dust came from what is now north-west Argentina, from where it was transported almost completely around the globe by the prevailing westerly winds. After a voyage of up to 20,000 kilometres, it contributed significantly to the increased input of iron into the glacial South Pacific. The dust input from Australia, which dominates in the South Pacific today, played only a minor role."We have analysed the chemical fingerprint of the dust and compared it with geological data from several continents. This was laborious work, like a jigsaw puzzle," says Struve, a post-doctoral scientist in the research group "Marine Isotope Geochemistry" at the University's Institute for Chemistry and Biology of the Marine Environment (ICBM). The team included researchers from his group as well as colleagues from the Alfred Wegener Institute -- Helmholtz Centre for Polar and Marine Research, Bremerhaven (Germany), and from Columbia University, New York (USA).The researchers sampled 18 sediment cores from the South Pacific between Antarctica, New Zealand and Chile, a study area which is roughly the size of Russia. Subsequently, they investigated the chemical composition of the dust contained in the samples. "This dust ultimately stems from rock, which has characteristic properties depending on its place of origin and geologic history so that each source has its own signature," Struve explains.The researchers focused on trace metals, in particular rare earth elements and specific isotopes, that is variants of different weight, of the elements neodymium, lead and strontium. This signature is preserved over millions of years and thus provides reliable information about the origin of rock particles even after 20,000 years.At that time, the last Ice Age was at its peak. According to the results, westerly winds blew dust particles from the eastern side of the central Andes in South America across the Atlantic and the Indian Ocean. As such, the iron-bearing dust was transported once around the globe before being deposited in the middle latitudes of the South Pacific. Since algae in these waters usually lack iron as a crucial nutrient for growth, iron-containing dust acts as a natural fertiliser until today.Like all plants, phytoplankton -- microscopic algae -- absorbs carbon by means of photosynthesis and thus reduces the proportion of carbon dioxide (COIt was already known that the iron input during the last ice age was much higher than during the present warm period. "But we were surprised to find that the sources and transport routes of the dust were completely different from today and also different from what we would have expected."The research team concludes that the unusually high dust emissions from South America must have made a significant contribution to the reduction of COToday, no dust from South America can be detected in the study area. "Global warming has changed the winds and environmental conditions in the source regions," Struve says, who continues to study the sediment cores. Together with his colleagues, he wants to find out how the composition of the dust has changed since the peak of the ice age and how this may have contributed to climate change.
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Climate
| 2,020 |
November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110102540.htm
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New study uses satellites and field studies to improve coral reef restoration
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Our planet's coral reef ecosystems are in peril from multiple threats. Anthropogenic CO
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With most of the world's reefs under stress, "coral gardening" or "outplanting" has become a popular and promising solution for restoration. Outplanting involves transplanting nursery-grown coral fragments onto degraded reefs. When successful, outplanting helps build coral biomass and restore reef function; but even with thousands of corals outplanted each year, the results are mixed. Newly settled corals are particularly vulnerable to stressors such as pollution, unfavorable light conditions, and temperature fluctuations. Therefore, identifying which stressors have the greatest bearing on coral health and survival is crucial for ensuring successful reef restoration.A recent study published in "New restoration protocols can use remotely sensed data of multiple oceanographic variables to assess the environmental history of a site. This will help evaluate and optimize site selection and give their outplants the best chance of survival.," said Shawna Foo, lead author and postdoctoral researcher at GDCS.The study was based on an analysis of coral outplanting projects worldwide between 1987 and 2019. The team assessed satellite-based data on multiple oceanographic variables including POC, PAR, salinity, sea surface temperature, and surface currents to quantify and assess each environmental driver's relative importance to and influence on coral outplant survival."Our results provide, for the first time, a clear set of conditions needed to maximize the success of coral restoration efforts. The findings are based on a vast global dataset and provide a critically needed compass to improving the performance of coral outplants in the future," said Greg Asner, co-author of the study and director of GDCS.Notably, the researchers observed better survival rates for corals outplanted farther away from the coast than six kilometers. This finding has implications for many restoration projections which are often located near land for accessibility purposes, such as diving operations. The researchers also found better coral recovery in water deeper than six meters; corals outplanted in shallow waters showed elevated vulnerability to disturbance and bleaching. Overall, coral outplants had the greatest chance of survival in regions with stable PAR, lower levels of POC, minimal temperature anomalies, and increased water depth and distance away from land. The researchers note that finding restoration sites with all of these characteristics could pose a challenge in some areas, but a consideration of all drivers in combination will greatly help the chances of outplant survival.
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Climate
| 2,020 |
November 9, 2020
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https://www.sciencedaily.com/releases/2020/11/201109152241.htm
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In a warming world, Cape Town's 'Day Zero' drought won't be an anomaly
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Today, the lakes around Cape Town are brimming with water, but it was only a few years ago that South Africa's second-most populous city made global headlines as a multi-year drought depleted its reservoirs, impacting millions of people. That kind of extreme event may become the norm, researchers now warn.
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Using new high-resolution simulations, researchers from Stanford University and the National Oceanic and Atmospheric Administration (NOAA) concluded that human-caused climate change made the "Day Zero" drought in southwestern South Africa -- named after the day, barely averted, when Cape Town's municipal water supply would need to be shut off -- five to six times more likely. Furthermore, such extreme events could go from being rare to common events by the end of the century, according to the study, published November 9 in the journal "In a way, the 'Day Zero' drought might have been a sort of taste of what the future may be," said lead author Salvatore Pascale, a research scientist at Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth). "In the worst-case scenario, events like the 'Day Zero' drought may become about 100 times more likely than what they were in the early 20th-century world."Using a climate modeling system known as the Seamless System for Prediction and EArth System Research (SPEAR), the researchers simulated the response of atmospheric circulation patterns to increasing levels of carbon dioxide.The model found that in a high greenhouse gas-emissions scenario, a devastating drought like the one that crippled Cape Town could impact the region two or three times in a decade. Even in an intermediate-emissions scenario, the risk of multi-year droughts that are more extreme and last longer than the "Day Zero" drought will increase by the end of the century.The new research uses higher resolution models than were previously available and supports the conclusions of past studies that projected an increase in drought risk. The findings underscore the area's sensitivity to further emissions and need for aggressive water management."The information we can provide now with these new tools is much more precise," Pascale said. "We can say with a higher degree of confidence that the role anthropogenic climate change has had so far has been quite large."Other parts of the world with similar climates to South Africa -- including California, southern Australia, southern Europe and parts of South America -- could experience their own Zero Day droughts in the future, according to the researchers. "Analysis like this should be conducted for thorough water risk management," said co-author Sarah Kapnick, a research physical scientist and deputy division leader at NOAA's Geophysical Fluid Dynamics Laboratory."Given the dramatic shift in multi-year drought risk, this work also serves as an example for other regions to explore their changing drought risks," Kapnick said. "Emerging drought risks may not be on the radar of managers in other regions in the world who have not experienced a recent rare drought event."Meteorological droughts, or rainfall deficits, like the one that affected Cape Town have high societal and economic impacts. According to estimates, lower crop yields from the "Day Zero" drought caused an economic loss of about $400 million, in addition to tens of thousands of jobs."This study shows these events will be more likely in the future depending on how energetic we are in addressing the climate problem," Pascale said. "It can be either catastrophic or just a little bit better, but still worse than what it is now -- this is trying to give some indication about what the future might look like."Three consecutive years of dry winters from 2015-17 in southwestern South Africa led to the severe water shortage from 2017-18. Cape Town never actually reach "Day Zero," in part because authorities implemented water restrictions throughout the period, banning outdoor and non-essential water use, encouraging toilet flushing with grey water and eventually limiting consumption to about 13 gallons per person in February 2018. That level of conservation was foreign to many residents of the coastal tourist destination and would likely be jarring to many in the U.S., where the average person goes through 80 to 100 gallons per day, according to the United States Geological Survey (USGS)."I'm sure that many Cape Town residents have forgotten what happened now that lakes and water reservoirs are back to normal," Pascale said. "But this is the moment to rethink the old way of managing water for a future when there will be less water available."Thomas Delworth and William Cooke from NOAA are co-authors on the study.The research was supported by NOAA and Stanford University.
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Climate
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November 9, 2020
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https://www.sciencedaily.com/releases/2020/11/201109152233.htm
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Marine fisheries will not offset farm losses after nuclear war
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After a nuclear war, wild-catch marine fisheries will not offset the loss of food grown on land, especially if widespread overfishing continues, according to a Rutgers co-authored study.
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But effective pre-war fisheries management would greatly boost the oceans' potential contribution of protein and nutrients during a global food emergency, according to the study in the journal "Nuclear war that causes global climate cooling could lead to far less food from farms on land, and increased fishing would not be a panacea," said co-author Alan Robock, a Distinguished Professor in the Department of Environmental Sciences in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick. "We should do everything possible to prevent even a small, localized nuclear war since that could have dire consequences for people and our planet."Aside from the devastating direct impacts, a nuclear war would likely cause global disruptions in the Earth's climate by injecting millions of tons of soot from massive fires into the upper atmosphere, blocking sunlight. Lower surface temperatures and less sunlight could drive unprecedented declines in agricultural production, endangering global food security.Scientists simulated the climatic impacts of six nuclear war scenarios -- a large conflict involving the United States versus Russia and five lesser ones between India and Pakistan -- on fish biomass (the weight of fish stocks) and fish catch. They used a state-of-the-art Earth system model and a global fisheries model. They also simulated how an increased demand for fish, driven by food shortages, or a decrease in fishing due to infrastructure disruptions would affect global catches. In addition, they studied the benefits of strong pre-war fisheries management.Assuming business-as-usual fishing and widespread overfishing, the models show the global fish catch falling by up to 29 percent after a nuclear war, depending on the amount of soot injected into the upper atmosphere. Due to rising demand, the catch would temporarily increase by about 30 percent -- for one to two years -- followed by losses of up to about 70 percent, offsetting only a small fraction of agricultural losses."Strong fisheries regulation pre-war could instead allow catches to become many times higher than normal in the first year post-war, even despite large soot inputs," the study says.The next steps, according to Robock, include factoring in the impacts on farmed fish (about half of global marine fisheries), combining the impacts of nuclear war on global food availability from agriculture and fishing, and factoring in economic impacts, including how trade would affect food prices in different locations.
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Climate
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November 9, 2020
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https://www.sciencedaily.com/releases/2020/11/201109132446.htm
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Global analysis of forest management shows local communities often lose out
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Maintaining forest cover is an important natural climate solution, but new research shows that too often, communities lose out when local forest management is formalised.
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The new study published today in It provides the most comprehensive global analysis of CFM to date and shows that whilst CFM policies often have positive environmental and economic impacts, CFM often results in weakened rights and less access to forests for local populations.Around the world, 1.6 billion people live within 5km (3 miles) forest, with 71% located in low or middle income countries."Improving forests can be a vital way to both tackle climate change and address poverty -- however, our study shows that too often local communities lose out when the management of community forests is formalised by governments," said Dr. Oldekop. "With the clock ticking on catastrophic climate change, the world needs to learn from successes in countries like Nepal, where we saw some cases with simultaneous economic, environmental, and resource rights outcomes."Previous research by Dr. Oldekop demonstrated that community-forest management in Nepal led to a 37% relative reduction in deforestation and a 4.3% relative reduction in poverty.Around the globe, forests regulate climate, sequester carbon, are home to a large proportion of the worlds plants and animals and contribute substantially to the livelihoods of people living in or near them."Around 14% of forests worldwide and 28% of forests in low-middle-income countries are formally owned or managed by Indigenous people and local communities," said Reem Hajjar. "Case studies that show positive outcomes abound. But gaining a better understanding of the trade-offs -- this outcome got better but at the expense of other outcomes getting worse -- is critical for understanding forest governance systems' potential for addressing multiple sustainability objectives at the same time."The new study analysed 643 examples of CFM in Latin America, Africa and Asia-Pacific, to gain a better understanding of the social, economic and environmental trade-offs which are occurring and what changes can help ensure goals across the spectrum are successful.However, clear trade-offs were visible in cases which assessed joint outcomes. Of the 122 studies which looked at all three CFM goals, just 18% reported positive outcomes across the three goals."Community Forest Management can improve both forests and the lives of the people near them. While it is heartening to see improving incomes in 68% of cases, reduced environmental impacts in 56% and gains in resource rights in 34% of cases, the overall results are significantly less transformative than they could be. Governments need to do more to ensure it's a triple win for people and the environment, rather than a series of trade-offs between them," added Dr Oldekop.
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Climate
| 2,020 |
November 9, 2020
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https://www.sciencedaily.com/releases/2020/11/201109074105.htm
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Scientists unravel how and why Amazon trees die
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The capacity of the Amazon forest to store carbon in a changing climate will ultimately be determined by how fast trees die -- and what kills them. Now, a huge new study has unravelled what factors control tree mortality rates in Amazon forests and helps to explain why tree mortality is increasing across the Amazon basin.
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This large analysis found that the mean growth rate of the tree species is the main risk factor behind Amazon tree death, with faster-growing trees dying off at a younger age. These findings have important consequences for our understanding of the future of these forests. Climate change tends to select fast-growing species. If the forests selected by climate change are more likely die younger, they will also store less carbon.The study, co-led by the Universities of Birmingham and Leeds in collaboration with more than 100 scientists, is the first large scale analysis of the causes of tree death in the Amazon and uses long-term records gathered by the international RAINFOR network.The results published in "Understanding the main drivers of tree death allows us to better predict and plan for future trends -- but this is a huge undertaking as there are more than 15,000 different tree species in the Amazon," said lead author Dr Adriane Esquivel-Muelbert, of the Birmingham Institute of Forest Research.Dr David Galbraith, from the University of Leeds added "We found a strong tendency for faster-growing species to die more, meaning they have shorter life spans. While climate change has provided favourable conditions for these species, because they also die more quickly the carbon sequestration service provided by Amazon trees is declining."Tree mortality is a rare event so to truly understand it requires huge amounts of data. The RAINFOR network has assembled more than 30 years of contributions from more than 100 scientists. It includes records from 189 one-hectare plots, each visited and monitored on average every 3 years. Each visit, researchers measure all trees above 10cm in diameter as well as the condition of every tree.In total more than 124,000 living trees were followed, and 18,000 tree deaths recorded and analysed. When trees die, the researcher follows a fixed protocol to unravel the actual cause of death. "This involves detailed, forensic work and amounts to a massive 'CSI Amazon' effort conducted by skilled investigators from a dozen nations," noted Prof. Oliver Phillips, from the University of Leeds.Dr Beatriz Marimon, from UNEMAT, who coordinates multiple plots in central Brazil added: "Now that we can see more clearly what is going on across the whole forest, there are clear opportunities for action. We find that drought is also driving tree death, but so far only in the South of the Amazon. What is happening here should serve as an early warning system as we need to prevent the same fate overtaking trees elsewhere."
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Climate
| 2,020 |
November 7, 2020
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https://www.sciencedaily.com/releases/2020/11/201107133920.htm
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Mystery of glacial lake floods solved
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A long-standing mystery in the study of glaciers was recently -- and serendipitously -- solved by a team led by University of Hawai'i at Manoa astrobiologist and earth scientist Eric Gaidos. Their findings were published this week in the journal
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The mystery involves floods or "jokulhlaups" that emerge suddenly and unpredictably from glaciers or ice caps like those in Iceland where volcanic heat melts the ice and water accumulates in lakes underneath the glaciers. Scientists have long studied the development of these floods, which are some of the largest on Earth."These floods may affect the motion of some glaciers and are a significant hazard in Iceland," said Gaidos, professor at the UH Manoa School of Ocean and Earth Science and Technology (SOEST). "But the mechanism and timing of the initiation of these floods has not been understood."Then, in June 2015, an unexpected series of events revealed how these floods start.That summer, Gaidos and colleagues drilled a hole to one of the Icelandic lakes to study its microbial life. While collecting samples through the borehole, the team noticed a downwards current, like a bathtub drain, in the hole."The flow was so strong we nearly lost our sensors and sampling equipment into the hole," said Gaidos. "We surmised that we had accidentally connected a water mass inside the glacier to the lake beneath. That water mass was rapidly draining into the lake."A few days later, after the team had left the glacier, the lake drained in a flood. Fortunately, the flood was small and Icelanders have an elaborate early-warning system on their rivers so no people were hurt, nor infrastructure damaged in this event, Gaidos assured.The researchers used a computer model of the draining of the flow through the hole , and its effect on the lake, to show that this could have triggered the flood."We discovered that the glacier can contain smaller bodies of water above the lakes fed by summer melting," said Gaidos. "If this water body is hydraulically connected to the lake then the pressure in the lake rises and that allows water to start draining out underneath the glacier."While the team made an artificial connection to the lake in 2015, natural connections can form when water from rain or melting snow accumulates in crevasses and the pressure eventually forces a crack through the glacier to the lake. This discovery provides a new understanding of how these floods can start and how this depends on weather and the season.Collaborators in Iceland are continuing to research this phenomenon using radio echo-sounding to search for water bodies within the ice, as well as study the larger lake below it.
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Climate
| 2,020 |
November 6, 2020
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https://www.sciencedaily.com/releases/2020/11/201106093027.htm
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Climate change and food demand could shrink species' habitats by almost a quarter by 2100
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Mammals, birds and amphibians worldwide have lost on average 18% of their natural habitat range as a result of changes in land use and climate change, a new study has found. In a worst-case scenario this loss could increase to 23% over the next 80 years.
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The study, published today in the journal A diverse abundance of species underpins essential ecosystem functions from pest regulation to carbon storage. Species' vulnerability to extinction is strongly impacted by their geographical range size, and devising effective conservation strategies requires a better understanding of how ranges have changed in the past, and how they will change under alternative future scenarios."The habitat size of almost all known birds, mammals and amphibians is shrinking, primarily because of land conversion by humans as we continue to expand our agricultural and urban areas," said Dr Robert Beyer in the University of Cambridge's Department of Zoology, first author of the report.Some species are more heavily impacted than others. A worrying 16% of species have lost over half their estimated natural historical range, a figure that could rise to 26% by the end of the century.Species' geographical ranges were found to have recently shrunk most significantly in tropical areas. Until around 50 years ago, most agricultural development was in Europe and North America. Since then, large areas of land have been converted for agriculture in the tropics: clearance of rainforest for oil palm plantations in South East Asia, and for pasture land in South America, for example.As humans move their activities deeper into the tropics, the effect on species ranges is becoming disproportionately larger because of a greater species richness in these areas, and because the natural ranges of these species are smaller to begin with."The tropics are biodiversity hotspots with lots of small-range species. If one hectare of tropical forest is converted to agricultural land, a lot more species lose larger proportions of their home than in places like Europe," said Beyer.The results predict that climate change will have an increasing impact on species' geographical ranges. Rising temperatures and changing rainfall patterns will alter habitats significantly, for example: other studies have predicted that without climate action, large parts of the Amazon may change from canopy rainforest to a savannah-like mix of woodland and open grassland in the next 100 years."Species in the Amazon have adapted to living in a tropical rainforest. If climate change causes this ecosystem to change, many of those species won't be able to survive -- or they will at least be pushed into smaller areas of remaining rainforest," said Beyer.He added: "We found that the higher the carbon emissions, the worse it gets for most species in terms of habitat loss."The results provide quantitative support for policy measures aiming at limiting the global area of agricultural land -- for example by sustainably intensifying food production, encouraging dietary shifts towards eating less meat, and stabilising population growth.The conversion of natural vegetation to agricultural and urban land, and the transformation of suitable habitat caused by climate change are major causes of the decline in range sizes, and two of the most important threats to global terrestrial biodiversity."Whether these past trends in habitat range losses will reverse, continue, or accelerate will depend on future global carbon emissions and societal choices in the coming years and decades," Professor Andrea Manica in the University of Cambridge's Department of Zoology, who led the study.He added: "While our study quantifies the drastic consequences for species' ranges if global land use and climate change are left unchecked, they also demonstrate the tremendous potential of timely and concerted policy action for halting -- and indeed partially reversing -- previous trends in global range contractions. It all depends on what we do next."
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Climate
| 2,020 |
November 6, 2020
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https://www.sciencedaily.com/releases/2020/11/201105183811.htm
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After election: Making the endangered species act more effective
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For forty-seven years, the Endangered Species Act has stood as the nation's strongest and most effective law for protecting animals and plants threatened with extinction -- from the bald eagle to the American burying beetle, the Alabama leather flower to the Aleutian shield fern.
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In 2019, the Trump Administration made the most sweeping changes to the implementation of the Endangered Species Act in decades -- making it harder for the federal government to protect the habitats that plants and animals will need in a warmer future. Many biologists and environmental groups have called for these rules to be reversed, to simply return to the Obama era rules.Now a leading group of conservation scientists and ESA policy experts are making the case that a "rule reversal" will not be sufficient to allow the Act to do its job of protecting species. Instead, they're calling for deeper improvements to the rules the U.S. Fish & Wildlife Service and the National Marine Fisheries Service use to apply the law -- aiming to make the Act more effective and to gain bipartisan and industry support in an era of accelerating climate change.The team's analysis and policy recommendations were published on November 5 in the journal "It's not enough to just go back to where we were eighteen months ago; we need reform," says University of Vermont conservation biologist Joe Roman, one of the co-authors on the new policy study. "We're not talking about revising the Act itself -- that legislative can of worms -- but it is clear that endangered species, wildlife agencies, landowners, and citizens would all benefit by updating the regulations and policies that are used to implement the law."At the center of the team's call for reform is a need for clarity.Consider the divergent cases of the Pacific walrus and the Arctic ringed seal. Both animals face similar threats from rapid losses of sea ice and snow cover. But a 2017 decision not to protect the walrus was based on climate projections that went out only to 2060, because the Fish & Wildlife Service considered conclusions beyond this date to be "based on speculation, rather than reliable prediction." However, five years earlier, the National Marine Fisheries Service listed the seal as "threatened" based on modeling that was presented as "reliable" out to 2100, the same time horizon as the authoritative modeling of the IPCC (the Intergovernmental Panel on Climate Change) and others.In short, the wildlife services have had an ad hoc and inconsistent approach to defining the "foreseeable future," -- and other ESA rules. "This kind of ambiguity hurts everybody," says Ya-Wei (Jake) Li, an expert on the Endangered Species Act at the Environmental Policy Innovation Center and the lead author of the new study in For example, once the National Marine Fisheries Service had "concluded that the extent of the of sea ice loss was reliably foreseeable to 2100, any conflicting decisions should explain why that conclusion was wrong," write the team of scientists, including Li, Roman, David S. Wilcove at Princeton University, Timothy Male at the Environmental Policy Innovation Center, and Holly Doremus at the University of California, Berkeley. "What is required is consistency and transparency."The federal wildlife services, the team argues, should clarify the principles that guide their decisions, provide more public access to the data behind decisions, and give clear explanations of how they exercise discretion in offering -- or not offering -- protections to threatened species.In a puzzling case, the U.S. Fish & Wildlife Service, using a so-called ESA 4(d) rule, offered the Gunnison sage grouse full protections on agricultural lands, but the related lesser prairie chicken was exempted from similar protections on the same kind of farmland. "The agency may have had valid reasons for this discrepancy, but they never publicly explained those reasons," the team writes."The recommendations that we're focusing on provide the public with more transparency -- and transparency alone can really help reduce a lot of the controversy" that has mired the ESA in recent years, says Jake Li. "But we're also advocating for new ideas that would bring better science and more flexible approaches to the decisions the wildlife services make."For example, in the wake of this presidential election, a new package of regulation and funding for working with landowners -- to offer tax incentives for easements and land donations -- could unlock recovery opportunities for the many threatened plants and animals that persist on private lands. And investments in remote sensing and other technologies could give a better view of how climate change will impact the nearly 2,400 species protected by the ESA."A strong majority of Americans supports the Endangered Species Act and sees wildlife and wild plants as a public good," says Joe Roman, a professor in UVM's Rubenstein School of Environment & Natural Resources and Gund Institute for Environment. "So what will it take to help landowners protect these species? Think of what could happen if we got federal decisionmakers, governors, conservationists, industry leaders to sit down together to help both species and landowners. With the right leadership, you could get broad bipartisan support to make the Endangered Species Act an even better tool for preventing the loss of biodiversity."
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Climate
| 2,020 |
November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105183834.htm
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Global-scale animal ecology reveals behavioral changes in response to climate change
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Using a new large-scale data archive of animal movement studies, an international team including University of Maryland biologists found that animals are responding in unexpected ways to climate change. The archive contains data from studies across the global Arctic and sub-Arctic, an enormous region that is experiencing some of the most dramatic effects of global warming, including animal declines.
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After developing the archive, the researchers used it to conduct three case studies that revealed surprising patterns and associations between climate change and the behavior of golden eagles, bears, caribou, moose and wolves. This work demonstrates both the feasibility and importance of studying animal ecology on extremely large scales. A research paper describing the archive and case studies appears in the November 6, 2020, issue of the journal "I'm really excited about how this work shows what you can learn from comparing data across populations on a very large scale," said Elie Gurarie, an associate research scientist in UMD's Department of Biology and a co-author of the paper. "I would say this is an early example of what we might call global animal movement ecology. We're increasing our ability to monitor the pulse of animal populations across the Earth and ask big picture questions about what it means."Large-scale monitoring of things like sea-surface temperature and global forest cover have revealed important information about the response of Earth's systems to climate change and human activity. But big-picture trends in animal behavior have been difficult to study, in part because animal ecology is not traditionally studied across landscapes that span entire regions of the globe, and also because the necessary data are collected by a variety of agencies and jurisdictions and are therefore neither standardized nor easily accessible.To address these issues, Gurarie and his collaborators spent years building relationships with scientists from national, regional and First Nations governments and research groups throughout the Arctic to convey the benefits of sharing data in a global repository that they call the Arctic Animal Movement Archive (AAMA). Currently, the archive includes contributions from researchers from over 100 universities, government agencies and conservation groups across 17 countries.The archive includes data from 201 terrestrial and marine animal tracking studies representing more than 8,000 animals between 1991 and the present. Using this data, Gurarie and members of his lab analyzed the movements of more than 900 female caribou from 2000 to 2017. They found that the iconic long-distance migrating caribou are giving birth earlier in the spring, roughly tracking rates of warming. But among the non-migratory mountain and lowland woodland caribou only the northern sub-populations are showing similar changes. While the drivers of these differences remain a mystery, understanding their behavior is critical to anticipating how they will respond as the Arctic continues to warm and many populations continue to decline."It's tricky to predict how these trends might impact populations," Gurarie said. "On the one hand, it can be better to give birth earlier, as it gives the calves more opportunity to grow during the summer season. On the other hand, giving birth too early may mean you literally don't have time to reach the optimal calving grounds. The ability to look at biological processes, like birth, at such a large scale, across populations and subspecies and over millions of square kilometers, is unprecedented for a species in such a remote and harsh environment. These results reveal patterns that we would not have suspected, and point to further lines of inquiry about everything from caribou evolution to their ability to adapt to environmental changes moving forward."Data analysis tools Gurarie developed to study caribou were also used for another case study led by his collaborators.In an analysis comparing movements of more than 100 golden eagles from 1993 to 2017, Scott LaPoint, a researcher from Columbia University who is now at Black Rock Forest Consortium, found that immature birds migrating north in the spring arrived earlier following mild winters, while adult birds did not. The timing shift for young birds varied in response to a large-scale climate cycle called the Pacific Decadal Oscillation, which is being affected by climate change. Such age-related behavior changes could only be seen through decades of movement data and may have implications for breeding success.A third study by Peter Mahoney of the University of Washington looked at the movement speeds of bears, caribou, moose and wolves from 1998 to 2019. His study showed that species respond differently to seasonal temperatures and winter snow conditions. Those differences could influence species interactions, food competition and predator-prey dynamics.The scientists expect that other researchers will continue to mine the AAMA for answers to pressing questions about whether and how animals are responding to a changing Arctic. Meanwhile, the resource continues to expand as more data comes in from currently tracked animals and more researchers add their studies."This work has given us a baseline to understand the large-scale picture so we can get a sense of how animals and environments are really interacting across species and across space as the environment changes," Gurarie said.
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Climate
| 2,020 |
November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105183809.htm
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Past is key to predicting future climate, scientists say
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An international team of climate scientists suggests that research centers around the world using numerical models to predict future climate change should include simulations of past climates in their evaluation and statement of their model performance.
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"We urge the climate model developer community to pay attention to the past and actively involve it in predicting the future," said Jessica Tierney, the paper's lead author and an associate professor in the University of Arizona's Department of Geosciences. "If your model can simulate past climates accurately, it likely will do a much better job at getting future scenarios right."As more and better information becomes available about climates in Earth's distant history, reaching back many millions of years before humans existed, past climates become increasingly relevant for improving our understanding of how key elements of the climate system are affected by greenhouse gas levels, according to the study's authors. Unlike historic climate records, which typically only go back a century or two -- a mere blink of an eye in the planet's climate history -- paleoclimates cover a vastly broader range of climatic conditions that can inform climate models in ways historic data cannot. These periods in Earth's past span a large range of temperatures, precipitation patterns and ice sheet distribution."Past climates should be used to evaluate and fine-tune climate models," Tierney said. "Looking to the past to inform the future could help narrow uncertainties surrounding projections of changes in temperature, ice sheets, and the water cycle."Typically, climate scientists evaluate their models with data from historical weather records, such as satellite measurements, sea surface temperatures, wind speeds, cloud cover and other parameters. The model's algorithms are then adjusted and tuned until their predictions mesh with the observed climate records. Thus, if a computer simulation produces a historically accurate climate based on the observations made during that time, it is considered fit to predict future climate with reasonable accuracy."We find that many models perform very well with historic climates, but not so well with climates from the Earth's geological past," Tierney said.One reason for the discrepancies are differences in how the models compute the effects of clouds, which is one of the great challenges in climate modeling, Tierney said. Such differences cause different models to diverge from each other in terms of what climate scientists refer to as climate sensitivity: a measure of how strongly the Earth's climate responds to a doubling of greenhouse gas emissions.Several of the latest generation models that are being used for the next report by the Intergovernmental Panel on Climate Change, or IPCC, have a higher climate sensitivity than previous iterations, Tierney explained."This means that if you double carbon dioxide emissions, they produce more global warming than their previous counterparts, so the question is: How much confidence do we have in these very sensitive new models?"In between IPCC reports, which typically are released every eight years, climate models are being updated based on the latest research data."Models become more complex, and in theory, they get better, but what does that mean?" Tierney said. "You want to know what happens in the future, so you want to be able to trust the model with regard to what happens in response to higher levels of carbon dioxide."While there is no debate in the climate science community about human fossil fuel consumption pushing the Earth toward a warmer state for which there is no historical precedent, different models generate varying predictions. Some forecast an increase as large as 6 degrees Celsius by the end of the century.Tierney said while Earth's atmosphere has experienced carbon dioxide concentrations much higher than today's level of about 400 parts per million, there is no time in the geological record that matches the speed at which humans are contributing to greenhouse gas emissions.In the paper, the authors applied climate models to several known past climate extremes from the geological record. The most recent warm climate offering a glimpse into the future occurred about 50 million years ago during the Eocene epoch, Tierney said. Global carbon dioxide was at 1,000 parts per million at that time and there were no large ice sheets."If we don't cut back emissions, we are headed for Eocene-like COThe authors discuss climate changes all the way to the Cretaceous period, about 90 million years ago, when dinosaurs still ruled the Earth. That period shows that the climate can get even warmer, a scenario that Tierney described as "even scarier," with carbon dioxide levels up to 2,000 parts per million and the oceans as warm as a bathtub."The key is COSome models are much better than others at producing the climates seen in the geologic record, which underscores the need to test climate models against paleoclimates, the authors said. In particular, past warm climates such as the Eocene highlight the role that clouds play in contributing to warmer temperatures under increased carbon dioxide levels."We urge the climate community to test models on paleoclimates early on, while the models are being developed, rather than afterwards, which tends to be the current practice," Tierney said. "Seemingly small things like clouds affect the Earth's energy balance in major ways and can affect the temperatures your model produces for the year 2100."
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Climate
| 2,020 |
November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105183741.htm
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Shifts in water temperatures affect eating habits of larval tuna at critical life stage
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Small shifts in ocean temperature can have significant effects on the eating habits of blackfin tuna during the larval stage of development, when finding food and growing quickly are critical to long-term survival, a new study from Oregon State University researchers has found.
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In a year of warmer water conditions, larval blackfin tuna ate less and grew more slowly, in part because fewer prey were available, compared to the previous year, when water conditions were one to two degrees Celsius cooler, the researchers found.The findings provide new insight into the relationship between larval tuna growth and environmental conditions, as well as the broader impacts of climate change on marine fish populations. As the climate continues to warm, over the long term, increasing water temperatures may interact with changing food webs to pose critical problems for fish populations, the researchers said."There was a drastic difference in the fish between the two years. It was obvious tuna in one year had very full guts with much bigger prey," said Miram Gleiber, the study's lead author. Gleiber worked on the project as part of her doctoral dissertation at Oregon State and has since completed her Ph.D."This gives us a better understanding of how these fish are surviving in this vulnerable early life stage as temperatures change. It's not just the temperature change that is important, but the impacts on prey are also important."The study results were published today in the Blackfin tuna are among the smallest tuna species and are one of the most common larval fish found in the Straits of Florida, a region with a high diversity of fish species. Blackfin tunas' diets are similar to other, more commercially popular tuna species such as bluefin and albacore, which make them a good model for studying how tuna respond to constraints in the food web, such as those induced by warming temperatures."It's common for fish to produce lots of eggs," Sponaugle said. "But past research has shown that any small change that occurs early in a fish's life has big implications down the road. What happens during this larval stage of development can greatly influence the whole population."Researchers collected hundreds of samples of larval blackfin tuna throughout the Straits of Florida during research cruises in 2014 and 2015. During those cruises, the researchers also documented the prey environment for the fish using an imaging system that measures distribution of zooplankton -- on which the blackfin feed -- in the sampling area.Researchers also collected data on water temperature, which averaged about 1.2 degrees Celsius higher in 2015 than in 2014."Anecdotally, even before we started our data collection and analysis, you could see there were about 10 times more blackfin tuna in 2014 than in 2015," Gleiber said. "This particular tuna is known to be abundant in this area, so one of the questions we wanted to answer was why were there so many more in one year compared to the other? We thought it might be related to their diet."Gleiber spent about a year painstakingly dissecting and analyzing the stomach contents of hundreds of larval tuna, which were 3 to 10 millimeters in size, to determine what and how much they were eating. She also removed and studied the fishes' otoliths -- small ear stones that researchers can use to determine the age and growth rate of the fish."These otoliths are like tiny onions, depositing a little material every day in concentric layers smaller than the width of a human hair. We can use this record just like tree rings to estimate fish age and daily growth," Sponaugle said.Fish generally tend to grow faster in warmer temperatures and tuna are a fast-growing species, which heightens their need for adequate food sources.But a comparison of the two years of samples, including stomach contents, growth rate data from the ear stones and information about available prey from the imaging system, showed that in the warmer water conditions, the blackfin ate less, ate different prey that were smaller in size and grew more slowly."It's not just the temperature that determines their growth. Growth has to be supported with prey availability, as well," Gleiber said.Although the study was based on only two years of data, the results indicate a clear relationship between water temperature, the abundance of zooplankton prey and larval fish growth and survival."We saw these big differences with just a degree or two of temperature change," Sponaugle said. "That's a concern because if prey are not available or are reduced in numbers in warmer conditions, these young tuna just won't survive."
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Climate
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November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105183739.htm
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To limit global warming, the global food system must be reimagined
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Fossil fuel burning accounts for the majority of global greenhouse gas emissions, and to the world's credit, several countries are working to reduce their use and the heat-trapping emissions that ensue. The goal is to keep global temperatures under a 1.5° to 2°C increase above preindustrial levels -- the upper limits of the Paris Climate Agreement.
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If we stopped burning all fossil fuels this minute, would that be enough to keep a lid on global warming?Acording to UC Santa Barbara ecology professor David Tilman, petroleum energy sources are only part of the picture. In a paper published in the journal The source? Our food system."Global food demand and the greenhouse gases associated with it are on a trajectory to push the world past the one-and-a-half degree goal, and make it hard to stay under the two degree limit," said Tilman, who holds a dual appointment at UCSB's Bren School of Environmental Science & Management and at the University of Minnesota. The world's growing population as well as its diet are driving food production practices that generate and release massive and increasing amounts of carbon dioxide, methane and other greenhouse gases into the atmosphere. According to the paper, left unchecked, agricultural emissions alone could exceed the 1.5°C limit by about 2050.These findings are especially concerning given that we haven't stopped using fossil fuels, Tilman said. And with a 1°C average increase in global temperature since 1880, we've got only a slim margin before global warming results in widespread sea level rise, ocean acidification, biodiversity loss and other effects that will change life as we know it."All it would take for us to exceed the two degree warming limit is for food emissions to remain on their path and one additional year of current fossil fuel emissions," Tilman said. "And I guarantee you, we're not going to stop fossil fuel emissions in a year."Reducing the emissions from food production, "will likely be essential" to keeping the planet livable in its current state, according to the scientists."It's well known that agriculture releases about 30% of all greenhouse gases," Tilman said. Major sources include deforestation and land clearing, fertilizer overuse and gassy livestock, all of which are increasing as the global population increases. In "high-yield" countries such as the U.S., which have the benefit of large scale modern agriculture, intensive animal farming and heavy-handed fertilizer use are major contributors of greenhouse gases. Meanwhile, in "low yield" countries such as those in sub-Saharan Africa, population growth and increasing affluence are driving demand for more food, and toward more "urban" diets that are richer in meat and meat products, Tilman explained."Their demand for food is going up, but the farmers don't have the resources to have high yields, so they just clear more and more land," he said.And yet, it isn't as though we can just stop producing food, which is perhaps the main reason why agricultural emissions have received less attention than fossil fuels as a target for reduction, according to the researchers."You can't look at agriculture as if we can somehow get rid of it," said Tilman, whose research focuses on the environmental impacts of agriculture, as well as the links between diet, environment and health. "We need it; it's essential for society."But, according to the paper's authors, global warming does not have to be an unavoidable impact of feeding the the world. Through early and widespread adoption of several feasible food system strategies, it is possible to limit emissions from agriculture in a way that keeps us from exceeding the 2°C limit by the end of the century while feeding a growing population.The most effective, according to the paper, is a switch toward more plant-rich diets, which aren't just healthier overall, but also reduce the demand for beef and other ruminant meats. That, in turn, reduces the pressure to clear for grazing land or produce the grains and grasses (more farming, more fertilizer) required to feed them."We're not saying these diets have to be vegetarian or vegan," Tilman said. Widespread reduction of red meat consumption to once a week and having protein come from other sources such as chicken or fish, while increasing fruits and vegetables, in conjunction with decreasing fossil fuel use, could help keep the planet livably cool in the long run.Another strategy: ease up on fertilizer."Many countries have high yields because from 1960 until now they have been using more and more fertilizer," he said. "But recent research has shown that almost all of these countries are actually using much more than they need to attain the yield they have." A drop of roughly 30% in fertilizer use would not only save the farmer money for the same yield, it prevents the release of nitrous oxide that occurs when excess fertilizer goes unused."About 40% of all future climate warming from agriculture may come from nitrous oxide from fertilizer," Tilman added. "So adding the right amount of fertilizer has a large benefit for climate change and would save farmers money."Other strategies the researchers explored included adjusting global per capita calorie consumption to healthy levels; improving yields to help meet demand where it may reduce the pressure to clear more land; and reducing food waste by half."The nice thing is that we can do each of these things sort of halfway and still solve the problem," Tilman said. The sooner we employ these strategies, the closer we can get to keeping the Earth cool and avoiding the wholesale changes we would have to adopt if we wait too much longer, he added."I'm optimistic," he said. "We have a viable path for achieving global environmental sustainability and better lives for all of us."
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Climate
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November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105134513.htm
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Corn and other crops are not adapted to benefit from elevated carbon dioxide levels
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The U.S. backs out of the Paris climate agreement even as carbon dioxide (CO
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Most plants (including soybeans, rice, canola, and all trees) are C3 because they fix COWhen crops are grown in elevated CO"As scientists, we need to think several steps ahead to anticipate what the Earth will look like five to 30 years from now, and how we can design crops to perform well under those conditions," said Charles Pignon, a former postdoctoral researcher at Illinois. "We decided that a literature review and a retrospective analysis of biochemical limitations in photosynthesis would be able to give us some insight into why C4 crops might not respond and how we might alter this."The literature review, published in The team assembled a dataset of photosynthesis measurements from 49 C4 species, including the crops that could reveal photosynthetic limitations. The consistent pattern that emerged was that at low CO"This finding is analogous to a car assembly line where the supply of engines is outpacing the supply of chassis to accept them," said co-author Stephen Long, the Stanley O. Ikenberry Chair Professor of Plant Biology and Crop Sciences. "We need to engineer these plants to better balance their resources in one or both of two-ways."First, the authors suggest that C4 crops need to cut back on the amount of the enzyme used to fix COSecondly, they need to restrict the supply of COThe WEST project concluded in 2019. These proposed changes to C4 crops are now being pursued through the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), which is supported by the Department of Energy.
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Climate
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November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105112945.htm
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Utilizing a 'krafty' waste product: Toward enhancing vehicle fuel economy
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Given concerns over global climate warming, researchers are hard at work on minimizing the amount of fuel that we all use in everyday life. Reducing the weight of vehicles will lessen the amount of fuel required to power them, and put money back into your pocket.
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In a study recently published in The researchers started with Kraft lignin, a byproduct of a common wood pulping process. Paper mills usually burn Kraft lignin to generate power, because it's difficult to use for anything except specialized purposes. Chemically processing Kraft lignin into a more useful material would improve the environmental sustainability of paper production."We performed a chemical modification of Kraft lignin polymer known as acetylation," says first author László Szabó. "Optimizing the extent of acetylation was critical to our research effort."A controlled reaction was important for optimizing Kraft lignin's ability to be compatible with another polymer called polyacrylonitrile, and thus prepare quality carbon fibers creating an engineered composite. If there's too little -- or too much -- acetylation, the carbon fibers are of low quality."Our reaction was quite mild, producing only a rather benign side product -- acetone -- without changing the polydispersity of the Kraft lignin," explains Kenji Takahashi, co-senior author. "We thus were able to mix Kraft lignin with polyacrylonitrile to obtain a dope solution for electrospinning containing more compatible polymer segments and eventually fabricate quality carbon fibers."The researchers' carbon fiber mats contain fine uniform fibers, without the thermal treatment lessening fiber quality. In fact, compared with unmodified Kraft lignin, by using the modified polymer the fiber mat exhibited an almost 3-fold improvement in mechanical strength."Our fibers' mechanical performance is attributable to the tailored graphitic structure of the materials," explains Szabó. "This outcome is owing to the improved polymer interactions leading to a more aligned polymeric network which is then subjected to the thermal treatment."Engineered composites are common in spacecraft, cars, plastic, concrete, and many other products and technologies. When these researchers minimize the cost of preparing their new carbon fibers, perhaps vehicles of the future will be lighter, more durable, and more fuel-efficient. Given that every industry uses transportation, everyone will save money and every business will be more environmentally sustainable.
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Climate
| 2,020 |
November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105112936.htm
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Species more likely to die out with rapid climate changes
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The climate seems to be getting warmer. This could be bad news for species that depend on stable and abundant access to food at certain times of the year.
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"If the changes happen too fast, species can become extinct," says Emily Simmonds, an associate professor at the Norwegian University of Science and Technology's (NTNU) Department of Biology.She is the first author of an article in Several bird species depend on the abundance of larvae while their young are small. If the larvae supply peaks earlier in the spring than normal, there may simply be too little food for the hatchlings.The warming climate can bring about changes like this. An earlier spring causes trees to leaf out earlier, which in turn causes the larvae that feed on the plants to hatch out earlier."When the climate changes, the interactions between different species changes too," Simmonds says.She and a team of researchers at the University of Oxford used population models to calculate the consequences of different climate scenarios. They wanted to see at what point the changes would happen too fast for the great tit to modify its behaviour quickly enough to keep up with the larvae.Great tits have genetic variations and varying abilities to adapt to different conditions. This means that they can evolve in tandem with their prey up to a point.An earlier larvae hatch can be advantageous for the great tits that also hatch their young earlier in the spring. This advantage can be transferred to the next generation of birds, which can in turn become early birds. And so on.For this advantage to last, the great tits have to evolve fast enough and be flexible enough to keep up with the genetic variation in their prey."Given conditions with big greenhouse gas emissions, the great tits won't always be able to keep up with the changes in the larvae supply," says Simmonds.In the worst case scenario, whole populations of great tits will simply disappear by the year 2100 because they aren't able to procure enough food for their young."This could happen even if the great tits are also modifying their behaviour faster in a rapidly changing environment. The larvae might be changing even faster than the great tits," Simmonds says.The researchers found that populations of great tits would be guaranteed to become extinct by the year 2100 if the larvae appeared about 24 days earlier than the current norm in 2020. This also applies to populations that appear to be completely stable now."It could be that the apparent stability today is hiding a future collapse," says Simmonds.The reason is that we might reach a kind of threshold where the great tits aren't keeping up. The rubber band gets stretched too far, you could say."The good news is that the populations will be able to survive scenarios with lower or medium warming trends," Simmonds says.Simmonds collaborated with Dr. Ella Cole, Professor Ben Sheldon and Professor Tim Coulson at the University of Oxford on the project, which was part of Simmonds' doctoral dissertation at the British university.
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Climate
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November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105113019.htm
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Seabirds' response to abrupt climate change transformed sub-Antarctic island ecosystems
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The Falkland Islands are a South Atlantic refuge for some of the world's most important seabird species, including five species of penguins, Great Shearwaters, and White-chinned Petrels. In recent years, their breeding grounds in the coastal tussac (Poa flabellata) grasslands have come under increasing pressure from sheep grazing and erosion. And unlike other regions of the globe, there has been no long-term monitoring of the responses of these burrowing and ground nesting seabirds to climate change.
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A 14,000-year paleoecological reconstruction of the sub-Antarctic islands done by an international research team led by The University of Maine (UMaine) including Dr Moriaki YASUHARA from the School of Biological Sciences and The Swire Institute of Marine Science, The University of Hong Kong (HKU), has found that seabird establishment occurred during a period of regional cooling 5,000 years ago. Their populations, in turn, shifted the Falkland Island ecosystem through the deposit of high concentrations of guano that helped nourish tussac, produce peat and increase the incidence of fire. The findings were recently published in the journal "This terrestrial-marine link is critical to the islands' grasslands conservation efforts going forward," says Dulcinea GROFF, who led the research as a PhD student in UMaine. "The connection of nutrients originating in the marine ecosystem that are transferred to the terrestrial ecosystem enrich the islands' nutrient-poor soil, thereby making the Falkland Islands sensitive to changes in climate and land use."Our work emphasizes just how important the nutrients in seabird poop are for the ongoing efforts to restore and conserve their grassland habitats. It also raises the question about where seabirds will go as the climate continues to warm," said Groff, who conducted the research in the Falkland Islands during expeditions in 2014 and 2016 led by Jacquelyn GILL, an Associate Professor of paleoecology and plant ecology in the UMaine Climate Change Institute.The UMaine expedition team collected a 476-centimeter peat column from Surf Bay, East Falkland. The 14,000-year record revealed in the undecomposed tussac leaves of the peat column captures the development of a terrestrial-marine linkage that supports some of the most important breeding colonies of seabirds in the Southern Ocean today.The absence of seabirds at the East Falklands site prior to 5,000 years ago suggests that seabirds may be sensitive to warmer mediated sea surface temperatures, which can impact their food supply, according to the research team. With a warming South Atlantic today, the question is whether the Falkland Islands, about 300 miles east of South America, will continue to be a seabird breeding "hot spot." The research team suggests that as the Southern Ocean continues to warm in the coming decades, the Falkland Islands seabird communities may undergo abrupt turnover or collapse, which could happen on the order of decades.The 14,000-year record from East Falkland revealed that for 9,000 years before the arrival of seabirds, the region was dominated by low levels of grasses, a heathland of ferns and dwarf Ericaceous shrubs. About 5,000 years ago, the researchers says, an "abrupt transition" appears to occur. Concentrations in bio-elements such as phosphorus and zinc increase. Grass pollen accumulation rates skyrocket, indicating the establishment of tussac grasslands within 200 years of the establishment of seabird colonies on the island. Also found in the core: increased accumulation rates of peat and charcoal. "This timing is consistent with that of the Southern Ocean cooling that known paleoclimatic records consistently indicate.," said Yasuhara, a paleoecologist and paleoclimatologist in HKU, who is familiar with polar paleoclimatology and paleoceanography.It is clear that the addition of seabird populations bringing nutrients from the marine environment to the island drove changes in the terrestrial plant community structure, composition and function, as well as increased fire activity and nutrient cycling. What remains unclear is what drove the abrupt ecosystem shift, including the impacts of climate change and extinction, and the geographical distribution of living things through space and time."Our study is also a powerful reminder of why we need to understand how different ecosystems are connected as the world warms," says Gill. "Such understanding is especially important in polar regions and ecosystems that are known to be sensitive to climate change," continues Yasuhara. Gill concluded, "We know that many seabirds in the South Atlantic rely on these unique coastal grasslands, but it turns out that the grasses also depend on the nutrients seabirds provide. Because they rely on ecosystems in the ocean and on land for their survival, seabirds are really excellent sentinels of global change. We just don't have good long-term monitoring data for most of these species, so we don't know enough about how sensitive they are to climate change. The fossil record can help us fill in the gaps."
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Climate
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November 4, 2020
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https://www.sciencedaily.com/releases/2020/11/201104143649.htm
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Identifying communities at risk for impacts of extreme heat
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An analysis of ways to measure a community's vulnerability to climate change suggests that California's current method may leave some at-risk communities behind in efforts to reduce health impacts of extreme heat. Lynée Turek-Hankins of Stanford University (now currently at the University of Miami) and colleagues present these findings in the open-access journal
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As climate change progresses, governments are increasingly interested in equity-oriented policies to aid communities that may be particularly at risk of health impacts and death due to extreme heat. Risk may vary between communities according to unique socioeconomic, health, and environmental factors. However, how to accurately identify vulnerable communities is unclear.To gain new insight, Turek-Hankins and colleagues conducted a systematic comparison of three methods to measure a community's vulnerability to climate change. They compared the CalEnviroScreen 3.0 index, which focuses on pollution; the Social Vulnerability Index, which applies to all types of disasters; and the Heat-Health Action Index, which identifies areas particularly vulnerable to heat-related health impacts.The analysis found that CalEnviroScreen 3.0 identified 25 percent of California's communities as "disadvantaged." However, the other two indices identified an additional 12.6 percent of communities as being vulnerable to health impacts of extreme heat, and just 13.4 percent of communities were found to be vulnerable across all three indices.These findings are notable because CalEnviroScreen 3.0 is currently used by California to help determine which communities receive projects to adapt to the effects of climate change -- including extreme heat. In fact, communities identified as vulnerable by CalEnviroScreen 3.0 but not the Heat-Health Action Index have received four times as many heat-related projects as those found vulnerable by the Heat-Health Action Index but not CalEnviroScreen 3.0.These findings suggest that any single index on its own could overlook key nuances and prevent vulnerable communities from being selected for heat-related adaptation projects. The authors call for a more holistic approach to quantify not only vulnerability to extreme heat, but also vulnerability to other climate hazards.The authors add: "Government and community members across the country are ambitiously ramping up efforts for equity-oriented climate change adaptation, but questions about how to effectively identify and prioritize limited funding across communities in practice remain. Using a program from the state of California as a case study, we demonstrate that the selection of "disadvantaged" communities for adaptation funding as well as perceptions of overall risk depend greatly on the metrics one deploys."
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Climate
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November 4, 2020
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https://www.sciencedaily.com/releases/2020/11/201104143646.htm
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Sea-level rise will have complex consequences
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Rising sea levels will affect coasts and human societies in complex and unpredictable ways, according to a new study that examined 12,000 years in which a large island became a cluster of smaller ones.
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Researchers reconstructed sea-level rise to produce maps of coastal changes at thousand-year intervals and found that today's Isles of Scilly, off the UK's south-west coast, emerged from a single island that only became the current configuration of more than 140 islands less than 1,000 years ago.The study, led by the University of Exeter in partnership with Cornwall Archaeological Unit, Cardiff University and 14 other institutes, found that changes in both land area and human cultures happened at variable rates, and often out of step with the prevailing rate of sea-level rise.With climate change now driving rapid sea-level rise, the team says the effects will not always be as simple as a forced human retreat from coasts."When we're thinking about future sea-level rise, we need to consider the complexity of the systems involved, in terms of both the physical geography and the human response" said lead author Dr Robert Barnett, of the University of Exeter."The speed at which land disappears is not only a function of sea-level rise, it depends on specific local geography, landforms and geology."Human responses are likely to be equally localised. For example, communities may have powerful reasons for refusing to abandon a particular place."The researchers developed a new 12,000-year sea-level curve for the Isles of Scilly, and looked at this alongside new landscape, vegetation and human population reconstructions created from pollen and charcoal data and archaeological evidence gathered. The new research extends and enhances data collected by the Lyonesse Project (2009 to 2013), a study of the historic coastal and marine environment of the Isles of Scilly.These findings suggest that during a period between 5,000 and 4,000 years ago land was rapidly becoming submerged. In response to this period of coastline reorganisation, people appeared to adapt to, rather than abandon, the new landscape.By the Bronze Age (after 4400 years ago), the archaeological record suggests the area had a permanent population -- and instead of leaving the islands, it appears that there may have been a "significant acceleration of activity."The reasons for this are unclear, but one possibility is that new shallow seas and tidal zones provided opportunities for fishing, shellfish collection and hunting wildfowl.This period of rapid land loss happened at a time of relatively slow sea-level rise -- because lots of Scilly's land at that point was relatively flat and close to sea level.The study found that between 5000 and 4,000 years ago, land was being lost at a rate of 10,000 m2 per year, which is equivalent to a large international rugby stadium. However, about half of this land was turning into intertidal habitats, which may have been able to support the coastal communities.Charlie Johns (Cornwall Archaeological Unit) co-director of the Lyonesse Project said "This new research confirms that the period immediately before 4,000 years ago saw some of the most significant loss of land at any time in the history of Scilly -- equivalent to losing two-thirds of the entire modern area of the islands."After 4,000 years ago, the island group continued to be submerged by rising sea levels, even during modest (e.g., 1 mm per year) rates of sea-level rise."It is clear that rapid coastal change can happen even during relatively small and gradual sea-level rise," said Dr Barnett."The current rate of mean global sea-level rise (around 3.6 mm per year) is already far greater than the local rate at the Isles of Scilly (1 to 2 mm per year) that caused widespread coastal reorganisation between 5,000 and 4,000 years ago."It is even more important to consider the human responses to these physical changes, which may be unpredictable."As can be seen today across island nations, cultural practices define the response of coastal communities, which can result in polarised agenda, such as the planned relocation programmes in Fiji versus the climate-migration resistance seen in Tavalu."In the past, we saw that coastal reorganisation at the Isles of Scilly led to new resource availability for coastal communities."It is perhaps unlikely that future coastal reorganisation will lead to new resource availability on scales capable of supporting entire communities."More certain though, is that societal and cultural perspectives from coastal populations will be critical for responding successfully to future climate change."The research was funded by a grant from English Heritage (now Historic England) to the Cornwall Council Historic Environment Service (now Cornwall Archaeological Unit). Outputs from the original project (The Lyonesse project: A study of the historic coastal and marine environment of the Isles of Scilly (2016)) are also available from the Cornwall Archaeological Unit.
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Climate
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November 4, 2020
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https://www.sciencedaily.com/releases/2020/11/201104143628.htm
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DNA in seawater can reveal fish diversity in the deep ocean
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A new study demonstrates the effectiveness of a novel method for using DNA in seawater samples to determine which fish species are present in a given part of the deep sea. A team of scientists from eDNAtec Inc. and colleagues from Fisheries and Oceans Canada and Memorial University present these findings in the open-access journal
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The ability to monitor deep-sea fish diversity is necessary for implementing sustainable management efforts and understanding the impacts of commercial fishing and climate change. However, existing methods such as baited camera traps, trawling, and acoustic monitoring, have limited detection capabilities and are difficult to use in much of the ocean.A newer method called eDNA metabarcoding reveals which fish are present in a given habitat by analyzing environmental DNA (eDNA) -- DNA that is shed by organisms into the surrounding environment as they go about their normal activities.To evaluate the effectiveness of eDNA metabarcoding for detecting deep-sea fish, McClenaghan and colleagues applied it to seawater samples collected from the Labrador Sea at depths of up to 2,500 meters. In deep-sea water samples (depths of 1,400 meters or greater), eDNA metabarcoding identified 11 fish families, 11 genera, and 8 species. The researchers compared their eDNA metabarcoding results to those obtained by conventional methods and found that they provided broader coverage of fish diversity and other taxa while using significantly less logistical effort. These advantages make eDNA techniques an important advancement for large-scale monitoring applications.The research team also explored eDNA metabarcoding using various volumes of deep-ocean seawater samples and different DNA primers -- short strands of DNA applied in the laboratory analysis of eDNA to determine which species are present. Their findings suggest that the deep ocean environment requires some adjustments to methods used in shallower waters, such as using larger volumes of water and the use of multiple primers to maximize species detection.While the authors plan to further refine eDNA metabarcoding procedures for the unique nature of the deep-sea environment, they note that this method already can provide important insights for monitoring fish diversity in the deep ocean.The authors add: "Advances in genomics and computational tools are rapidly expanding our ability to study and monitor biodiversity, a much needed task in the face of rapid and vast environmental change. Our study demonstrates the utility of eDNA analysis for the challenging endeavour of monitoring fish species in deep ocean and sets the stage for adoption of this approach by various stakeholders."
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Climate
| 2,020 |
November 3, 2020
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https://www.sciencedaily.com/releases/2020/11/201103104723.htm
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Students develop tool to predict the carbon footprint of algorithms
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On a daily basis, and perhaps without realizing it, most of us are in close contact with advanced AI methods known as deep learning. Deep learning algorithms churn whenever we use Siri or Alexa, when Netflix suggests movies and tv shows based upon our viewing histories, or when we communicate with a website's customer service chatbot.
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However, the rapidly evolving technology, one that has otherwise been expected to serve as an effective weapon against climate change, has a downside that many people are unaware of -- sky high energy consumption. Artificial intelligence, and particularly the subfield of deep learning, appears likely to become a significant climate culprit should industry trends continue. In only six years -- from 2012 to 2018 -- the compute needed for deep learning has grown 300,000%. However, the energy consumption and carbon footprint associated with developing algorithms is rarely measured, despite numerous studies that clearly demonstrate the growing problem.In response to the problem, two students at the University of Copenhagen's Department of Computer Science, Lasse F. Wolff Anthony and Benjamin Kanding, together with Assistant Professor Raghavendra Selvan, have developed a software programme they call Carbontracker. The programme can calculate and predict the energy consumption and CO"Developments in this field are going insanely fast and deep learning models are constantly becoming larger in scale and more advanced. Right now, there is exponential growth. And that means an increasing energy consumption that most people seem not to think about," according to Lasse F. Wolff Anthony.Deep learning training is the process during which the mathematical model learns to recognize patterns in large datasets. It's an energy-intensive process that takes place on specialized, power-intensive hardware running 24 hours a day."As datasets grow larger by the day, the problems that algorithms need to solve become more and more complex," states Benjamin Kanding.One of the biggest deep learning models developed thus far is the advanced language model known as GPT-3. In a single training session, it is estimated to use the equivalent of a year's energy consumption of 126 Danish homes, and emit the same amount of CO2 as 700,000 kilometres of driving."Within a few years, there will probably be several models that are many times larger," says Lasse F. Wolff Anthony."Should the trend continue, artificial intelligence could end up being a significant contributor to climate change. Jamming the brakes on technological development is not the point. These developments offer fantastic opportunities for helping our climate. Instead, it is about becoming aware of the problem and thinking: How might we improve?" explains Benjamin Kanding.The idea of Carbontracker, which is a free programme, is to provide the field with a foundation for reducing the climate impact of models. Among other things, the programme gathers information on how much COAmong their recommendations, the two computer science students suggest that deep learning practitioners look at when their model trainings take place, as power is not equally green over a 24-hour period, as well as what type of hardware and algorithms they deploy."It is possible to reduce the climate impact significantly. For example, it is relevant if one opts to train their model in Estonia or Sweden, where the carbon footprint of a model training can be reduced by more than 60 times thanks to greener energy supplies. Algorithms also vary greatly in their energy efficiency. Some require less compute, and thereby less energy, to achieve similar results. If one can tune these types of parameters, things can change considerably," concludes Lasse F. Wolff Anthony.
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Climate
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November 2, 2020
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https://www.sciencedaily.com/releases/2020/11/201102155409.htm
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Hot or cold, weather alone has no significant effect on COVID-19 spread
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At the onset of the coronavirus pandemic, there were high hopes that hot summer temperatures could reduce its spread. Although summer didn't bring widespread relief, the connection between the weather and COVID-19 continues to be a hot topic.
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The link between weather and COVID-19 is complicated. Weather influences the environment in which the coronavirus must survive before infecting a new host. But it also influences human behavior, which moves the virus from one host to another.Research led by The University of Texas at Austin is adding some clarity on weather's role in COVID-19 infection, with a new study finding that temperature and humidity do not play a significant role in coronavirus spread.That means whether it's hot or cold outside, the transmission of COVID-19 from one person to the next depends almost entirely on human behavior."The effect of weather is low and other features such as mobility have more impact than weather," said Dev Niyogi, a professor at UT Austin's Jackson School of Geosciences and Cockrell School of Engineering who led the research. "In terms of relative importance, weather is one of the last parameters."The research was published Oct. 26 in the Co-authors are Sajad Jamshidi, a research assistant at Purdue University, and Maryam Baniasad, a doctoral candidate at Ohio State University.The study defined weather as "equivalent air temperature," which combines temperature and humidity into a single value. The scientists than analyzed how this value tracked with coronavirus spread in different areas from March to July 2020, with their scale ranging from U.S. states and counties, to countries, regions and the world at large.At the county and state scale, the researchers also investigated the relationship between coronavirus infection and human behavior, using cellphone data to study travel habits.The study examined human behavior in a general sense and did not attempt to connect it to how the weather may have influenced it. At each scale, the researchers adjusted their analyses so that population differences did not skew results.Across scales, the scientists found that the weather had nearly no influence. When it was compared with other factors using a statistical metric that breaks down the relative contribution of each factor toward a particular outcome, the weather's relative importance at the county scale was less than 3%, with no indication that a specific type of weather promoted spread over another.In contrast, the data showed the clear influence of human behavior -- and the outsized influence of individual behaviors. Taking trips and spending time away from home were the top two contributing factors to COVID-19 growth, with a relative importance of about 34% and 26% respectively. The next two important factors were population and urban density, with a relative importance of about 23% and 13% respectively."We shouldn't think of the problem as something driven by weather and climate," Jamshidi said. "We should take personal precautions, be aware of the factors in urban exposure."Baniasad, a biochemist and pharmacist, said that assumptions about how coronavirus would respond with weather are largely informed by studies conducted in laboratory settings on related viruses. She said that this study illustrates the importance of studies that analyze how the coronavirus spreads through human communities."When you study something in lab, it's a supervised environment. It's hard to scale up to society," she said. "This was our first motivation to do a more broad study."Marshall Shepherd, an atmospheric sciences professor at the University of Georgia who was not part of the study, said that the research offers important insights about weather and coronavirus across scales."This important work clarifies some of the innuendo about weather-COVID-19 connections and highlights the need to address science challenges at the appropriate scales," Shepherd said.Niyogi said that one of the key lessons of the coronavirus pandemic is the importance of analyzing phenomena at the "human scale" -- the scale at which humans live their day-to-day lives. He said that this research is an example of this type of perspective."COVID, it is claimed, could change everything," Niyogi said. "We have been looking at weather and climate outlooks as a system that we scale down, down, down and then seeing how it might affect humans. Now, we are flipping the case and upscaling, starting at human exposure scale and then going outwards. This is a new paradigm we will need for studying virus exposure and human environmental modeling systems involving new sensing and AI-like techniques."The University of Texas at Austin, NASA and the National Science Foundation funded the research.
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Climate
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November 2, 2020
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https://www.sciencedaily.com/releases/2020/11/201102133336.htm
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Longer mud season, no snow could alter northeast US rivers by 2100
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As temperatures begin to drop and fall transitions into winter, snow will soon blanket the northern regions of the United States. But researchers at the University of New Hampshire have found that snow cover is on the decline in this area due to climate change and the shift from winter to spring, known as the vernal window, is getting longer. By the end of the century, the scientists say the vernal window, sometimes referred to as mud season in the northeast, could be two to four weeks longer which means significantly less melting snow that could be detrimental to key spring conditions in rivers and surrounding ecosystems.
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"We found that climate change could alter the vernal window so much that by the year 2100, 59% of northeastern North America -- which goes from Maine to Virginia -- would not accumulate any snow," said Danielle Grogan research scientist in UNH's Earth Systems Research Center and lead author. "Historically, an average of 27% of the northeast goes without snow but by the end of century states like Connecticut and Pennsylvania could be snow free."In their study, recently published in the journal "Snow melt is a major event for rivers and forests in the northeast," said Grogan. "It moves nutrients from the land to the rivers, boosts water levels and triggers essential spring happenings like the migration of fish. Losing the snow and the melt would change ecosystems on many levels and remove key signals that would disrupt natural patterns like fish mating."Previous studies have examined how climate change will alter the vernal window but few have explored the impact on rivers and surrounding areas during this transitional period. Researchers say by lengthening the vernal window and decreasing snow melt conditions in this area it could become similar to southern snow-free regions and would be a fundamental change in the hydrologic character of the northeast.
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Climate
| 2,020 |
November 2, 2020
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https://www.sciencedaily.com/releases/2020/11/201102124923.htm
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Consequences of glacier shrinkage
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Researchers from the South Asia Institute and the Heidelberg Center for the Environment of Ruperto Carola investigated the causes of a glacial lake outburst with subsequent flooding in the Ladakh region of India. In order to frame the case study in a larger picture, the research team led by geographer Prof. Dr Marcus Nüsser used satellite images to create a comprehensive survey of glacial lakes for the entire Trans-Himalyan region of Ladakh. They were able to identify changes in the extent and number of glacial lakes over a 50-year period, including previously undocumented floods. This analysis allows them to better assess the future risk of such events, known as glacial lake outburst floods (GLOFs).
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"In the wake of global glacier shrinkage caused by climate change, the danger from glacial lake outburst floods is seen as an increasingly pressing problem," explains Prof. Nüsser of the South Asia Institute. An event like this unleashes huge amounts of water. Flash floods, for example, can wreak havoc on villages, agricultural areas, and infrastructure. To find out more about such events, the Heidelberg researchers studied a glacial lake outburst flood in Ladakh that destroyed houses, fields, and bridges in the village of Gya in August of 2014. Studies of the glacial lake, which is situated at 5,300 m above sea level, revealed a drastic short-tem lake level rise prior to the GLOF.The cause, as the scientists discovered, was a "previously little-known mechanism." "Increased glacial melting caused the lake level to rise quite rapidly. Instead of resulting in spillover, however, the thawing ice cores in the moraine, i.e. the glacier's debris field, drained through subsurface tunnels without disturbing the moraine's surface," states Nüsser. In addition to conducting field surveys, the scientists also interviewed the locals about their recollections of the GLOF event. On the basis of satellite images, the team additionally studied the evolution of the glacial lake since the 1960s in order to reconstruct possible GLOF events."The high temporal and high spatial remote sensing imagery from satellites supported by field surveys will allow us to better assess the possible risk of future outbursts in this region," adds the Heidelberg geographer. In light of recurring GLOFs, the new inventory can help us "re-evaluate the hazards, identify vulnerable locations, and develop possible adaptation measures," continues Nüsser. After the flood in Gya, for example, concrete walls were constructed along the undercut bank as a flood protection measure to safeguard the villages and fields from future floods.
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Climate
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November 2, 2020
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https://www.sciencedaily.com/releases/2020/11/201102120111.htm
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To predict how crops cope with changing climate, 30 years of experiments simulate future
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Five years ago, the United Nations committed to achieving the Sustainable Development Goal of Zero Hunger by 2030. Since then, however, world hunger has continued to rise. Nearly 9 percent of our global population is now undernourished, according to a 2020 report from the FAO, and climate variability is a leading factor driving us off course.
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Over the past 30 years, a network of 14 long-term research facilities spanning five continents has simulated future levels of carbon dioxide (COToday, a review published in "It's quite shocking to go back and look at just how much COThe reviews consider two groups of plants: most crops are C3 (including soybean, cassava, and rice), which are less efficient at turning COIn C3 crops, oxygen inhibits photosynthesis, which is diminished by increasing the concentration of COAs in their previous review, but this time with ten times more studies, the authors show that elevation of CO"So should we anticipate a bounty as COWhile CO"Lots of people have presumed that rising COOn a more positive note, the authors show that there is sufficient genetic variation within our major crops to overcome some of these negative effects and capitalize on the yield benefit of higher CO"We are driven by a motivation to prepare for the future and to identify the traits that are going to be important for maximizing this COResearchers should explore a wider variety of crops and genotypes as well as different management practices, such as seeding density, tillage, and cover crops, to find other solutions that are less burdensome on the environment, Ainsworth said.Also, the FACE community needs greater accessibility to all of the experimental results."We don't have a formal database of all of the FACE results from the last two decades of research," Ainsworth said. "There's an opportunity to put all of the information together in one place and make it openly accessible for everyone to use and to encourage more people to use the data to think about solutions.""The ideal solution will be that we dramatically decrease our release of CO
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Climate
| 2,020 |
November 2, 2020
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https://www.sciencedaily.com/releases/2020/11/201102120053.htm
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Artificial night lighting has widespread impacts on nature
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Artificial night-time lighting has a diverse range of effects across the natural world and should be limited where possible, researchers say.
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A team led by the University of Exeter brought together more than 100 studies and found "widespread" impacts on animals and plants.Changes to animals' bodies and behaviour -- especially hormone levels and patterns of waking and sleeping -- were consistently found.The study shows that levels of melatonin (a hormone regulating sleep cycles) were reduced by exposure to artificial lighting at night in all animal species studied."Lots of studies have examined the impacts of artificial night-time lighting on particular species or communities of species," said Professor Kevin Gaston, of the Environment and Sustainability Institute on Exeter's Penryn Campus in Cornwall."Our research brings those studies together -- and we find the effects are very diverse and very pervasive."Particularly strong responses are seen in hormone levels, the timing of daily activity in diurnal (daytime) species, and 'life-history' traits such as number of offspring."People may imagine this is all about powerful light, but in fact we are seeing a lot of responses at quite low levels of artificial light."Dr Dirk Sanders added: "We see differences in nocturnal and diurnal species."For rodents, which are mostly nocturnal, the duration of activity tended to be reduced by night-time lighting."In contrast, for birds -- with all of those included strictly diurnal -- artificial light led to an extension of the duration of their activity, with singing and foraging starting earlier."Previous studies have shown night-time lighting has wide-ranging impacts -- from reducing pollination by insects to trees budding earlier in spring.Like climate change, night-time lighting appears to benefit certain species in certain locations, but Professor Gaston said the clear message of the study was to reduce lighting where possible."Both climate change and night-time lighting are human-driven and enormously disruptive to the natural world," he said."Historically, we have not really worried about the impact of night-time lighting."Only now are we discovering its wide-ranging effects."Our study shows that we should, as a matter of principle, only use night-time lighting where we need it and no further, and at intensities that we need and no more."In effect, we need to view light like any other pollutant."Obviously it would be ridiculous to say 'switch the world's lights off' -- but we could reduce our use of light immensely with absolutely no impact on ourselves."Professor Gaston is the scientific advisor on a forthcoming landmark natural history series about the night-time, called "Earth at Night in Colour''. The series is released on Apple TV+ on December 4th.The study was funded by the Natural Environment Research Council (NERC).
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Climate
| 2,020 |
November 2, 2020
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https://www.sciencedaily.com/releases/2020/11/201102120048.htm
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Room temperature conversion of CO2 to CO: A new way to synthesize hydrocarbons
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Researchers at the National Institute of Standards and Technology (NIST) and their colleagues have demonstrated a room-temperature method that could significantly reduce carbon dioxide levels in fossil-fuel power plant exhaust, one of the main sources of carbon emissions in the atmosphere.
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Although the researchers demonstrated this method in a small-scale, highly controlled environment with dimensions of just nanometers (billionths of a meter), they have already come up with concepts for scaling up the method and making it practical for real-world applications.In addition to offering a potential new way of mitigating the effects of climate change, the chemical process employed by the scientists also could reduce costs and energy requirements for producing liquid hydrocarbons and other chemicals used by industry. That's because the method's byproducts include the building blocks for synthesizing methane, ethanol and other carbon-based compounds used in industrial processing.The team tapped a novel energy source from the nanoworld to trigger a run-of-the-mill chemical reaction that eliminates carbon dioxide. In this reaction, solid carbon latches onto one of the oxygen atoms in carbon dioxide gas, reducing it to carbon monoxide. The conversion normally requires significant amounts of energy in the form of high heat -- a temperature of at least 700 degrees Celsius, hot enough to melt aluminum at normal atmospheric pressure.Instead of heat, the team relied on the energy harvested from traveling waves of electrons, known as localized surface plasmons (LSPs), which surf on individual aluminum nanoparticles. The team triggered the LSP oscillations by exciting the nanoparticles with an electron beam that had an adjustable diameter. A narrow beam, about a nanometer in diameter, bombarded individual aluminum nanoparticles while a beam about a thousand times wider generated LSPs among a large set of the nanoparticles.In the team's experiment, the aluminum nanoparticles were deposited on a layer of graphite, a form of carbon. This allowed the nanoparticles to transfer the LSP energy to the graphite. In the presence of carbon dioxide gas, which the team injected into the system, the graphite served the role of plucking individual oxygen atoms from carbon dioxide, reducing it to carbon monoxide. The aluminum nanoparticles were kept at room temperature. In this way, the team accomplished a major feat: getting rid of the carbon dioxide without the need for a source of high heat.Previous methods of removing carbon dioxide have had limited success because the techniques have required high temperature or pressure, employed costly precious metals, or had poor efficiency. In contrast, the LSP method not only saves energy but uses aluminum, a cheap and abundant metal.Although the LSP reaction generates a poisonous gas -- carbon monoxide -- the gas readily combines with hydrogen to produce essential hydrocarbon compounds, such as methane and ethanol, that are often used in industry, said NIST researcher Renu Sharma.She and her colleagues, including scientists from the University of Maryland in College Park and DENSsolutions, in Delft, the Netherlands, reported their findings in "We showed for the first time that this carbon dioxide reaction, which otherwise will only happen at 700 degrees C or higher, can be triggered using LSPs at room temperature," said researcher Canhui Wang of NIST and the University of Maryland.The researchers chose an electron beam to excite the LSPs because the beam can also be used to image structures in the system as small as a few billionths of a meter. This enabled the team to estimate how much carbon dioxide had been removed. They studied the system using a transmission electron microscope (TEM).Because both the concentration of carbon dioxide and the reaction volume of the experiment were so small, the team had to take special steps to directly measure the amount of carbon monoxide generated. They did so by coupling a specially modified gas cell holder from the TEM to a gas chromatograph mass spectrometer, allowing the team to measure parts-per-millions concentrations of carbon dioxide.Sharma and her colleagues also used the images produced by the electron beam to measure the amount of graphite that was etched away during the experiment, a proxy for how much carbon dioxide had been taken away. They found that the ratio of carbon monoxide to carbon dioxide measured at the outlet of the gas cell holder increased linearly with the amount of carbon removed by etching.Imaging with the electron beam also confirmed that most of the carbon etching -- a proxy for carbon dioxide reduction -- occurred near the aluminum nanoparticles. Additional studies revealed that when the aluminum nanoparticles were absent from the experiment, only about one-seventh as much carbon was etched.Limited by the size of the electron beam, the team's experimental system was small, only about 15 to 20 nanometers across (the size of a small virus).To scale up the system so that it could remove carbon dioxide from the exhaust of a commercial power plant, a light beam may be a better choice than an electron beam to excite the LSPs, Wang said. Sharma proposes that a transparent enclosure containing loosely packed carbon and aluminum nanoparticles could be placed over the smokestack of a power plant. An array of light beams impinging upon the grid would activate the LSPs. When the exhaust passes through the device, the light-activated LSPs in the nanoparticles would provide the energy to remove carbon dioxide.The aluminum nanoparticles, which are commercially available, should be evenly distributed to maximize contact with the carbon source and the incoming carbon dioxide, the team noted.The new work also suggests that LSPs offer a way for a slew of other chemical reactions that now require a large infusion of energy to proceed at ordinary temperatures and pressures using plasmonic nanoparticles."Carbon dioxide reduction is a big deal, but it would be an even bigger deal, saving enormous amounts of energy, if we can start to do many chemical reactions at room temperature that now require heating," Sharma said.
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Climate
| 2,020 |
November 2, 2020
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https://www.sciencedaily.com/releases/2020/11/201102110010.htm
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Building cities with wood would store half of cement industry's current carbon emissions
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Buildings around us create a whopping one-third of global greenhouse gas emissions -- that is about ten times more than air traffic worldwide. In Europe alone about 190 million square metres of housing space are built each year, mainly in the cities, and the amount is growing quickly at the rate of nearly one percent a year.
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A recent study by researchers at Aalto University and the Finnish Environment Institute shows that shifting to wood as a building construction material would significantly reduce the environmental impact of building construction. The results show that if 80 percent of new residential buildings in Europe were made of wood, and wood were used in the structures, cladding, surfaces, and furnishings of houses, all together the buildings would store 55 million tons of carbon dioxide a year. That is equivalent to about 47 percent of the annual emissions of Europe's cement industry.'This is the first time that the carbon storage potential of wooden building construction has been evaluated on the European level, in different scenarios,' explains Ali Amiri, who is completing his doctorate at Aalto University. 'We hope that our model could be used as roadmap to increase wooden construction in Europe.The study is based on an extensive analysis of the literature. Drawing on 50 case studies, the researchers divided buildings into three groups according to how much wood they use and, as a consequence, how much carbon dioxide they store.The group with the least amount of wood stored 100 kg of carbon dioxide per square metre, the middle group stored 200 kg, and the group with the greatest amount of wood stored 300 kg per square metre (COThe researchers also looked at how Europe could achieve the tremendous cut by modelling a path for reaching the level of 55 million tons per year by 2040. If say, in 2020, 10 percent of new residential buildings were made of wood each storing 100 COEnergy efficiency is the most frequently used instrument for measuring the environmental impact of buildings. However, energy efficiency requires more insulation, efficient recovery of heat, and better windows. In fact, about half of the carbon footprint of zero-energy houses occurs before anyone has even lived in them.When the energy used in housing comes increasingly from renewable sources, the significance of the construction phase of the building's total environmental impact grows even more.'Certificates for green buildings used around the world, such as LEED and BREEAM, could better take the climate benefits of wood construction into account. So far, they are strongly focused on how energy is consumed during use,' Amiri says.In terms of wood products, a wooden building provides longer-term storage for carbon than pulp or paper. According to the study findings, a wooden building of 100 m'Wood construction is sustainable only if the wood comes from forests that are grown in a sustainable manner. Shifting from short-lived products, like paper, to products with a long life-cycle, like wooden construction materials, would help minimise the impact on European forests and the crucial carbon sinks they hold,' says postdoctoral researcher Juudit Ottelin.
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Climate
| 2,020 |
November 2, 2020
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https://www.sciencedaily.com/releases/2020/11/201102072915.htm
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Warming of 2°C would release billions of tons of soil carbon
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Global warming of 2°C would lead to about 230 billion tonnes of carbon being released from the world's soil, new research suggests.
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Global soils contain two to three times more carbon than the atmosphere, and higher temperatures speed up decomposition -- reducing the amount of time carbon spends in the soil (known as "soil carbon turnover").The new international research study, led by the University of Exeter, reveals the sensitivity of soil carbon turnover to global warming and subsequently halves uncertainty about this in future climate change projections.The estimated 230 billion tonnes of carbon released at 2°C warming (above pre-industrial levels) is more than four times the total emissions from China, and more than double the emissions from the USA, over the last 100 years."Our study rules out the most extreme projections -- but nonetheless suggests substantial soil carbon losses due to climate change at only 2°C warming, and this doesn't even include losses of deeper permafrost carbon," said co-author Dr Sarah Chadburn, of the University of Exeter.This effect is a so-called "positive feedback" -- when climate change causes knock-on effects that contribute to further climate change.The response of soil carbon to climate change is the greatest area of uncertainty in understanding the carbon cycle in climate change projections.To address this, the researchers used a new combination of observational data and Earth System Models -- which simulate the climate and carbon cycle and subsequently make climate change predictions."We investigated how soil carbon is related to temperature in different locations on Earth to work out its sensitivity to global warming," said lead author Rebecca Varney, of the University of Exeter.State-of-the-art models suggest an uncertainty of about 120 billion tonnes of carbon at 2°C global mean warming.The study reduces this uncertainty to about 50 billion tonnes of carbon.Co-author Professor Peter Cox, of Exeter's Global Systems Institute, said: "We have reduced the uncertainty in this climate change response, which is vital to calculating an accurate global carbon budget and successfully meeting Paris Agreement targets."The work was carried-out in collaboration with scientists from the Met Office and institutes in the USA and Sweden.
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Climate
| 2,020 |
October 30, 2020
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https://www.sciencedaily.com/releases/2020/10/201030144837.htm
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New drone technology improves ability to forecast volcanic eruptions
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Specially-adapted drones developed by a UCL-led international team have been gathering data from never-before-explored volcanoes that will enable local communities to better forecast future eruptions.
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The cutting-edge research at Manam volcano in Papua New Guinea is improving scientists' understanding of how volcanoes contribute to the global carbon cycle, key to sustaining life on Earth.The team's findings, published in Science Advances, show for the first time how it is possible to combine measurements from the air, earth and space to learn more about the most inaccessible, highly active volcanoes on the planet.The ABOVE project involved specialists from the UK, USA, Canada, Italy, Sweden, Germany, Costa Rica, New Zealand and Papua New Guinea, spanning volcanology and aerospace engineering.They co-created solutions to the challenges of measuring gas emissions from active volcanoes, through using modified long-range drones.By combining in situ aerial measurements with results from satellites and ground-based remote sensors, researchers can gather a much richer data set than previously possible. This enables them to monitor active volcanoes remotely, improving understanding of how much carbon dioxide (COWith a diameter of 10km, Manam volcano is located on an island 13km off the northeast coast of the mainland, at 1,800m above sea level.Previous studies have shown it is among the world's biggest emitters of sulphur dioxide, but nothing was known of its COVolcanic COAdding miniaturised gas sensors, spectrometers and sampling devices that are automatically triggered to open and close, the team was able to fly the drone 2km high and 6km away to reach Manam's summit, where they captured gas samples to be analysed within hours.Calculating the ratio between sulphur and carbon dioxide levels in a volcano's emissions is critical to determining how likely an eruption is to take place, as it helps volcanologists establish the location of its magma.Manam's last major eruptions between 2004 and 2006 devastated large parts of the island and displaced the population of some 4,000 people to the mainland; their crops destroyed and water supplies contaminated.Project lead Dr Emma Liu (UCL Earth Sciences) said: "Manam hasn't been studied in detail but we could see from satellite data that it was producing strong emissions. The resources of the in-country volcano monitoring institute are small and the team has an incredible workload, but they really helped us make the links with the community living on Manam island."Following the fieldwork, the researchers raised funds to buy computers, solar panels and other technology to enable the local community -- who have since put together a disaster preparedness group -- to communicate via satellite from the island, and to provide drone operations training to Rabaul Volcanological Observatory staff to assist in their monitoring efforts.ABOVE was part of the Deep Carbon Observatory (DCO), a global community of scientists on a ten-year quest to understand more about carbon in Earth.Volcanic emissions are a critical stage of the Earth's carbon cycle -- the movement of carbon between land, atmosphere, and ocean -- but COUnderstanding the factors that control volcanic carbon emissions in the present day will reveal how the climate has changed in the past and therefore how it may respond in the future to current human impacts.Co-author Professor Alessandro Aiuppa (University of Palermo) described the findings as 'a real advance in our field', adding: "Ten years ago you could have only stared and guessed what Manam's CO"If you take into account all the carbon released by global volcanism, it's less than a per cent of the total emission budget, which is dominated by human activity. In a few centuries, humans are acting like thousands of volcanoes. If we continue to pump carbon into the atmosphere, it will make monitoring and forecasting eruptions using aerial gas observations even harder."Co-author Professor Tobias Fischer (University of New Mexico), added: "In order to understand the drivers of climate change you need to understand the carbon cycle in the earth."We wanted to quantify the carbon emission from this very large carbon dioxide emitter. We had very few data in terms of carbon isotope composition, which would identify the source of the carbon and whether it is the mantle, crust or sediment. We wanted to know where that carbon comes from."
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Climate
| 2,020 |
October 30, 2020
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https://www.sciencedaily.com/releases/2020/10/201030122543.htm
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Future lake food webs in Subarctic have more biomass and contain more omega-3 fatty acids
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Subarctic regions are facing rapid changes in climate and land-use intensity. An international research team recently completed an investigation to see how these changes are affecting the food webs and fish communities of lakes in northern Finland. Biomasses and omega-3 fatty acids, EPA and DHA, were determined from the algal producers at the base of food web to large carnivorous fish from 20 lakes along a pronounced climatic and productivity gradient. Increasing nutrient load and rising temperature shift food webs towards murky water adapted communities.
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The team measured amount of fish and invertebrates from 20 subarctic lakes along climate and productivity gradient and determined the nutritional quality of organisms in each lake by measuring valuable omega-3 fatty acids, EPA and DHA, from primary producer algae communities to top predators.Researchers found major differences in the clear and murky water communities. Increasing temperature and productivity increased biomass of algal and cyprinid fish communities.Professor Kimmo Kahilainen from University of Helsinki, Lammi Biological Station, coordinated this lake research program."What we find in these food webs was community shift from clear water to murky lakes. We get a lot of fish from blue-green algal covered lakes, but there were no salmonid fishes anymore and the fish catch consisted almost exclusively of roach" says Kahilainen.Biomass in lake food webs is largely composed of water, carbohydrates, proteins and lipids. Part of lipids are nutritionally very important including essential omega-3 fatty acids, such as EPA and DHA, which are efficiently produced by certain algae, such as diatoms in subarctic regions.Invertebrates consume these algal basal producers and their EPA and DHA are transferred through the food web. Researchers measured EPA and DHA content from whole food web from algae to carnivorous fish in each lake."Algal community changed from diatoms to blue-green algae and their quality decreased from clear to murky lakes, similar decreasing quality was also observed in invertebrates," says the lead author of study Mr Ossi Keva, a PhD student from University of Jyväskylä.Despite decreasing prey item quality, the hypothesised cascading effects on fish was not observed. Instead, increasing fish biomass in murky lakes actually led to an increase in total fatty acids."Food webs in warmer and more productive environment do contain more fish and fatty acids, while the fish species itself shift from highly valued salmonids towards cyprinid dominated communities. Northern Finnish pristine subarctic lakes are not getting clearer in future, the change is more likely towards warmer and murky lakes modifying food web communities as well," Keva summarises.
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Climate
| 2,020 |
October 30, 2020
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https://www.sciencedaily.com/releases/2020/10/201030111748.htm
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Radical changes in ecosystems
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Earth and all the living organisms on it are constantly changing. But is there any way we can detect if these changes are occurring at an abnormal rate? What are the consequences of these changes for the organisms affected? An international team of researchers including scientists from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have developed a method of detecting such developments and tracking how new ecosystems are formed. They have published their findings in the specialist journal
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Changes in the environment are becoming increasingly apparent due to climate change. Temperatures are rising, there is either no rain at all or it falls in severe storms. These changes have an effect on ecosystems and the living conditions of the organisms within them. If the conditions within these ecosystems become too unfavourable for individual organisms, they either migrate or even become extinct. At the same time, new ecological niches arise that other species can populate or new species are created. 'The problem is knowing at which point we can say it's a new ecosystem,' explains Prof. Wolfgang Kießling from the Chair of Palaeoenvironmental Research at FAU. 'We have now developed a method that allows us to distinguish such events from normal background noise.'An ecosystem is considered new by scientists if extremely rapid changes in the range of organisms within it lead to a state that previously did not exist. The speed at which the changes occur is extremely important. Ecosystems are always changing to a certain extent. Significant shifts only occur above a certain limit, for example as caused by human-made climate change. Scientists are now able to precisely determine this limit using statistics.Times of increased change are extremely dynamic and pose special challenges for the species involved. Wolfgang Kießling and his colleagues successfully tested their method on fossil ecosystems from a period ranging over 66 million years and their results are alarming. The risk of extinction during such dynamic periods of change is twice to four times higher than under normal conditions. At the same time, however, there is a greater chance that new species migrate or are created. 'Changes have always occurred in ecosystems and they will continue to do so,' Kießling continues. 'In terms of protecting the environment, it's therefore important not to prevent changes in general, but to try and steer them in a direction that does not have an increased risk of extinction.'
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Climate
| 2,020 |
October 30, 2020
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https://www.sciencedaily.com/releases/2020/10/201029171632.htm
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Resilience in the face of climate change: Archaeological investigations reveal human adaptability in ancient Turkey
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An examination of two documented periods of climate change in the greater Middle East, between approximately 4,500 and 3,000 years ago, reveals local evidence of resilience and even of a flourishing ancient society despite the changes in climate seen in the larger region.
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A new study led by University of Toronto and Cornell University archaeologists working at Tell Tayinat in southeastern Turkey, demonstrates that human responses to climate change are variable and must be examined using extensive and precise data gathered at the local level. The study highlights how challenge and collapse in some areas were matched by resilience and opportunities elsewhere.The findings published today in "The study shows the end of the Early Bronze Age occupation at Tayinat was a long and drawn out affair that, while it appears to coincide with the onset of a megadrought 4,200 years ago, was actually the culmination of processes that began much earlier," says Tim Harrison, professor and chair of the Department of Near & Middle Eastern Civilizations in the Faculty of Arts & Science at the University of Toronto (U of T), and director of the Tayinat Archaeological Project. "The archaeological evidence does not point towards significant local effects of the climate episode, as there is no evidence of drought stress in crops.""Instead, these changes were more likely the result of local political and spatial reconfiguration."The mid-to late Early Bronze Age (3000-2000 BCE) and the Late Bronze Age (1600-1200 BCE) in the ancient Middle East are pivotal periods of early inter-connectedness among settlements across the region, with the development of some of the earliest cities and state-level societies. But these systems were not always sustainable, and both periods ended in collapse of civilisations/settlements, the reasons for which are highly debated.The absence of detailed timelines for societal activity throughout the region leaves a significant gap in understanding the associations between climate change and social responses. While the disintegration of political or economic systems are indeed components of a societal response, collapse is rarely total.Using radiocarbon dating and analysis of archaeological samples recovered from Tell Tayinat, a location occupied following two particularly notable climate change episodes 4,200 and again 3,200 years ago, the Toronto-Cornell team established a robust chronological timeframe for Tayinat for these two pivotal periods in the history of the ancient Middle East."The absolute dating of these periods has been a subject of considerable debate for many years, and this study contributes a significant new dataset that helps address many of the questions," says Sturt Manning, Goldwin Smith Professor of Classical Archaeology in the Department of Classics at Cornell University's College of Arts & Sciences, and lead author of the study."The detailed chronological resolution achieved in this study allows for a more substantive interpretation of the archaeological evidence in terms of local and regional responses to proposed climate change, shedding light on how humans respond to environmental stress and variability."The researchers say the chronological framework for the Early Iron Age demonstrates the thriving re-settlement of Tayinat following the 3,200 years ago event during a reconstructed period of heightened aridity."The settlement of Tayinat may have been undertaken to maximize access to arable land, and crop evidence reveals the continued cultivation of numerous water-demanding crops, revealing a response that counters the picture of a drought-stricken region," says Harrison. "The Iron Age at Tayinat represents a significant degree of societal resilience during a period of climatic stress."The research was supported by the Social Sciences and Humanities Research Council of Canada and the University of Toronto.
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Climate
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October 30, 2020
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https://www.sciencedaily.com/releases/2020/10/201030111839.htm
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Expect more mega-droughts
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Mega-droughts -- droughts that last two decades or longer -- are tipped to increase thanks to climate change, according to University of Queensland-led research.
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UQ's Professor Hamish McGowan said the findings suggested climate change would lead to increased water scarcity, reduced winter snow cover, more frequent bushfires and wind erosion.The revelation came after an analysis of geological records from the Eemian Period -- 129,000 to 116,000 years ago -- which offered a proxy of what we could expect in a hotter, drier world."We found that, in the past, a similar amount of warming has been associated with mega-drought conditions all over south eastern Australia," Professor McGowan said."These drier conditions prevailed for centuries, sometimes for more than 1000 years, with El Niño events most likely increasing their severity."The team engaged in paleoclimatology -- the study of past climates -- to see what the world will look like as a result of global warming over the next 20 to 50 years."The Eemian Period is the most recent in Earth's history when global temperatures were similar, or possibly slightly warmer than present," Professor McGowan said."The 'warmth' of that period was in response to orbital forcing, the effect on climate of slow changes in the tilt of the Earth's axis and shape of the Earth's orbit around the sun.Professor Hamish McGowan wearing a headlamp crawling through a small cave to gain access to stalagmites around 120 metres below the surface in the Grotto Cave, NSW."In modern times, heating is being caused by high concentrations of greenhouse gases, though this period is still a good analogue for our current-to-near-future climate predictions."Researchers worked with the New South Wales Parks and Wildlife service to identify stalagmites in the Yarrangobilly Caves in the northern section of Kosciuszko National Park.Small samples of the calcium carbonate powder contained within the stalagmites were collected, then analysed and dated at UQ.That analysis allowed the team to identify periods of significantly reduced precipitation during the Eemian Period."They're alarming findings, in a long list of alarming findings that climate scientists have released over the last few decades," Professor McGowan said."We hope that this new research allows for new insights to our future climate and the risks it may bring, such as drought and associated bushfires."But, importantly, if humans continue to warm the planet, this is the future we may all be looking at."
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Climate
| 2,020 |
October 29, 2020
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https://www.sciencedaily.com/releases/2020/10/201029082204.htm
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International team tracks record-setting smoke cloud from Australian wildfires
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Researchers with the University of Saskatchewan's Institute of Space and Atmospheric Studies are part of a global team that has found that the smoke cloud pushed into the stratosphere by last winter's Australian wildfires was three times larger than anything previously recorded.
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The cloud, which measured 1,000 kilometres across, remained intact for three months, travelled 66,000 kilometres, and soared to a height of 35 kilometres above Earth. The findings were published in "When I saw the satellite measurement of the smoke plume at 35 kilometres, it was jaw dropping. I never would have expected that," said Adam Bourassa, professor of physics and engineering physics, who led the USask group which played a key role in analyzing NASA satellite data.Prior to Australia's "Black Summer," which burned 5.8 million hectares of forest in the southeast part of that continent, the smoke cloud caused by the 2017 forest fires in Western Canada was the largest on record.The international team was led by Sergey Khaykin from LATMOS (Laboratoire Atmosphères, Milieux, Observations Spatiales) in France. Bourassa said the team's findings provide critical information for understanding how wildfires are impacting the Earth's atmosphere."We're seeing records broken in terms of the impact on the atmosphere from these fires," said Bourassa. "Knowing that they're likely to strike more frequently and with more intensity due to climate change, we could end up with a pretty dramatically changed atmosphere." Bourassa, his post-doctoral student Landon Rieger, and research engineer Daniel Zawada were the only Canadians involved in the project. Bourassa's group has expertise in a specific type of satellite measurement that is very sensitive to smoke in the upper atmosphere. Their contributions were funded in part by the Canadian Space Agency. According to Bourassa, wildfires such as those in Australia and Western Canada get big enough and hot enough that they generate their own thunderstorms, called Pyrocumulonimbus. These, in turn, create powerful updrafts that push smoke and the surrounding air up past the altitudes where jets fly, into the upper part of the atmosphere called the stratosphere."What was also really amazing was that as the smoke sits in the atmosphere, it starts to absorb sunlight and so it starts to heat up," said Bourassa. "And then, because it's getting hotter, it starts to rise in a swirling vortex 'bubble', and it just rose and rose higher and higher through the atmosphere."Information collected by satellite, using an instrument called a spectrometer, showed smoke from the Australian wildfires blocked sunlight from reaching Earth to an extent never before recorded from wildfires.The measurement technique, proven by Canadian scientists including Bourassa over a decade ago, measures the sunlight scattered from the atmosphere back to the satellite, generating a detailed, image of layers in the atmosphere.The stratosphere is typically a "pretty pristine, naturally clean, stable part of atmosphere," Bourassa said. However, when aerosols -- such as smoke from wildfires or sulphuric acid from a volcanic eruption -- are forced up into the stratosphere, they can remain aloft for many months, blocking sunlight from passing through, which in turns changes the balance of the climate system.While researchers have a general understanding of how these smoke clouds form and why they rise high into the stratosphere, Bourassa said more work needs to be done to understand the underlying mechanisms.Researchers will also be comparing their findings from Australian wildfires with satellite data captured from California wildfires this past summer and fall.
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Climate
| 2,020 |
October 28, 2020
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https://www.sciencedaily.com/releases/2020/10/201028171423.htm
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New sulfur dioxide conversion method may transform current industrial techniques
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A single-step, plasma-enhanced catalytic process to convert sulfur dioxide to pure sulfur from tail gas streams may provide a promising, more environmentally-friendly alternative to current multistage thermal, catalytic and absorptive processes, according to scientists at Penn State.
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"Sulfur dioxides can cause significant environmental problems like acid rain, and it can cause sea acidification," said Xiaoxing Wang, associate research professor at the Penn State EMS Energy Institute. "Sulfur can also contribute to fine particulate matter in the air we breathe, which can be more severe than the sulfur dioxide itself."Exposure to particulate matter was estimated to cause 4.2 million premature deaths and more than 100 million disability-adjusted life years -- which measures years lost due to illness, disability or death -- according to the Lancet Global Burden of Diseases Study, published in 2015.According to Wang, current desulfurization methods can successfully remove sulfur dioxide from tail gas streams but not without significant drawbacks.Flue gas desulfurization technologies, for example, are the most used methods to capture sulfur dioxide, but these processes create a large amount of solid waste in the form of metal sulfate that requires disposal. Furthermore, these processes produce wastewater that requires additional treatment, making the overall method costly and environmentally unfriendly.Alternatively, sulfur dioxide can be reduced to solid elemental sulfur through catalysis -- a chemical reaction brought on by a catalyst and usually a reducing agent such as hydrogen, methane, or carbon monoxide -- and then used as a raw material for such things as fertilizer. However, high temperatures are normally needed in the traditional catalytic process to attain high conversion levels. This is not ideal because it uses a great deal of energy and there is a loss of catalyst activity, according to the scientists.Due to these flaws, Wang and his colleagues tested a novel technology, a one-step, low-temperature plasma-assisted catalytic process that eliminates the need for high temperatures and creates far less waste than FGD technologies.To test this process, the team loaded an iron sulfide catalyst into a packed bed reactor. Then they introduced the hydrogen and the sulfur dioxide gas mixtures, which passed through the catalyst bed at roughly 300 degrees Fahrenheit. They then turned on the nonthermal plasma and the reactions immediately began to occur.Once the process completed, they analyzed the samples to see how much sulfur dioxide was in the gas and how much hydrogen was consumed. They also collected and analyzed the solid sulfur, which accumulates at the bottom of the reactor. They published their results in ACS Catalysis and a recent issue of the "The temperature we used, 150 degrees C (about 300 degrees F), is higher than the sulfur melt point to avoid sulfur deposition over the catalyst," Wang said. "Through this process, the catalyst shows very excellent stability. When run for several hours, we do not see any deactivation. The activity and the selectivity stay the same."The researchers also found that this process dramatically promoted sulfur dioxide reduction at low temperatures, enhancing conversion by 148% to 200 percent and 87 to 120 percent using hydrogen and methane, respectively.Sean Knecht, assistant teaching professor in the School of Engineering Design, Technology and Professional Programs, said that NTP works because highly energetic electrons interact with gas molecules to produce reactive species -- radicals, ions and excited molecules -- enabling various chemical reactions at low temperature."The result is that the electrons are able to initiate what would appear to be thermodynamically-unfavorable chemical reactions through dissociation and excitation of reactants at much lower temperatures than thermal catalysis," Knecht said. "If these reactions can be undertaken at much lower temperatures than are typical for thermal catalysis, as we have shown, then the power input to future systems is significantly reduced, which is a big deal."Wang added that using plasma allows them to achieve optimal performance using just 10 watts of electricity. Another advantage is that renewable energy, such as wind or solar, can be easily applied to this process to supply power to the plasma.The researchers now want to better understand exactly how the plasma contributes to the catalysis process and seek to develop an even more effective catalyst for the process."A current challenge that we are working to address is further isolating the effects of the plasma versus effects of the catalyst and the synergistic aspects," Knecht said. "We are looking at some surface spectroscopy options presently and at some point, combining with computational modeling. Bringing these together can provide a more holistic understanding of the physics and chemistry at play."If the process is commercializable, it has the potential to largely replace the current FDG technologies."It's highly beneficial to energy and the environment," Wang said. "Our process saves energy, reduces waste and saves water. This is very transformational."Other contributing researchers included Mohammad S. AlQahtani, graduate student; Chunshan Song, distinguished professor emeritus at Penn State and dean of faculty of science and Wei Lun Professor of Chemistry at The Chinese University of Hong Kong; Sven G. Bilén, head of the School of Engineering Design, Technology, and Professional Programs and professor of engineering design, electrical engineering and aerospace engineering; and Jennifer L. Gray, staff scientist at the Materials Research Institute.A U.S. Department of Agriculture Sun Grant and a Penn State EMS Energy Institute seed grant provided funding for this research.
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Climate
| 2,020 |
October 28, 2020
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https://www.sciencedaily.com/releases/2020/10/201028171421.htm
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Location and extent of coral reefs mapped worldwide using advanced AI
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Nearly 75% of the world's coral reefs are under threat from global stressors such as climate change and local stressors such as overfishing and coastal development. Those working to understand and protect coral reefs are building the know-how to mitigate the damage but doing so requires first knowing where reefs are located.
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Many approaches, such as diver-based observation and satellite imagery, have been used to estimate the distribution of coral reefs around the world, but past approaches have led to inconsistent accuracy because the underlying data are derived from disparate sources and varying methodologies. Now, researchers from the Arizona State University Center for Global Discovery and Conservation Science (GDCS) have generated a global coral reef extent map using a single methodology capable of predicting the location of shallow coral reefs with nearly 90% accuracy.The GDCS team used convolutional neural networks (CNNs), an advanced artificial intelligence approach, along with thousands of satellite images from Planet Inc. to create the new global map. Planet's satellites obtain daily coverage of the Earth's landmass and its coral reefs at a 3.7-meter resolution. Many of these satellites are as small as a loaf of bread but, operating together, they collect over 11 terabytes of data every day. This continuous stream of imagery yields a massive amount of data -- too much for even a large team of scientists to manually sort through. Using convolutional neural networks and ASU's supercomputer, the GDCS team was able to analyze the data and extract the locations of shallow reefs less than 20 meters (70 feet) of water depth worldwide.The maps are openly available through the Allen Coral Atlas, a collaborative partnership between ASU, Vulcan Inc., Planet Inc., University of Queensland, and National Geographic Society to map and monitor the world's coral reefs in unprecedented detail."The new map represents our best estimate of the location of shallow coral reefs on the planet, and it guides next steps including our ongoing collaboration to map the composition of these reefs and their changing health over time," said first author, Jiwei Li, of GDCS.The researchers indicated that these new maps can be used with other global maps or datasets to create derived data or analytic products. Some immediate uses of the map at the Allen Coral Atlas include determining where to monitor for coral bleaching, a global phenomenon driven by ocean warming.Greg Asner, co-author of the study and ASU's Allen Coral Atlas lead explained, "This first-ever A.I.-driven map of the world's coral reefs is just a drop in the bucket compared to what we have coming out over the next year and beyond. The partnership is already rolling out much more detailed reef composition maps on a region by region basis, and we are preparing to launch a global reef monitoring system that detects bleaching. These and other large-scale marine technology innovations are already helping conservation, management and resource policy specialists make decisions. That's our big picture goal."
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Climate
| 2,020 |
October 28, 2020
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https://www.sciencedaily.com/releases/2020/10/201028110620.htm
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Climate change drives plants to extinction in the Black Forest in Germany
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Climate change is leaving its mark on the bog complexes of the German Black Forest. Due to rising temperatures and longer dry periods, two plant species have already gone extinct over the last 40 years. The populations of many others have decreased by one third. In the next couple of decades ten more species could become extinct, researchers from Martin Luther University Halle-Wittenberg (MLU) and the German Centre for Integrative Biodiversity Research (iDiv) write in
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There are only a few healthy ombrotrophic bogs, raised bogs and spring mires left in Germany. They used to cover large swathes of north-western Germany. Today they are still found in the foothills of the Alps and on low mountain ranges, for example in the Black Forest. They are very sensitive ecosystems that are highly dependent on certain climatic conditions. "These bogs and spring mires are seismographs of climate change. They react very sensitively to small changes in precipitation and temperature," says professor Helge Bruelheide, a geobotanist at MLU and co-director of iDiv. Bog complexes also have a very high proportion of endangered plant and animal species.Bruelheide joined forces with Thomas Sperle, a biologist and wetlands expert, to investigate the trends in biodiversity in bogs and spring mires in the southern region of the Black Forest. The two scientists drew on data from the 1970s about the vegetation of 124 complete bogs. Sperle completely re-surveyed nearly all of the areas over a period of four years. "It is really tricky to prove the extinction of a species for an entire bog. I had to carefully scan the whole area to ensure that specific individuals were not overlooked," says Sperle. Bruelheide then used the data to analyse the 88 plant species. Two species have already become extinct. The population size of another 37 have decreased by about one third since the 1970s. This has disproportionately affected so-called specialist species that are adapted to specific climatic conditions and make up a large portion of the biodiversity in Germany. However, there were also 46 so-called generalist species that have coped better with the changes and whose numbers have increased over time.The researchers also checked whether their observations could be explained by other factors, such as the size of the bogs, the distance from one bog to another and whether adjacent areas were used for agriculture. However, no factor could explain the data better than climate change. "Our analyses clearly show that species are declining and dying out in places where it is drier and warmer for longer periods of time in the summer. This is the first indication that climate change has already arrived in our latitudes," concludes Bruelheide. "It is getting noticeably drier and hotter in the Black Forest, which is why this change is evident there. Presumably, the same thing will happen in other low mountain ranges such as the Harz. Our study can serve as an example for other regions in Germany, but also for other habitats and groups of species."In their study, the biologists predict that ten more specialist species will disappear by 2045 if conditions progress as expected. This is an alarming sign as there is no way to counteract this extinction in raised bogs and spring moors. "You cannot really replace missing rain in those bogs," says Bruelheide.
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Climate
| 2,020 |
October 28, 2020
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https://www.sciencedaily.com/releases/2020/10/201028101846.htm
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The future is now: Long-term research shows ocean acidification ramping up on the Reef
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Ocean acidification is no longer a sombre forecast for the Great Barrier Reef but a present-day reality, a new study reveals.
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The study, published in the international "People talk about ocean acidification in terms of 50 years' time, but for the first time our study shows how fast ocean acidification is already happening on the Reef," said Dr Katharina Fabricius, lead author and Senior Principal Research Scientist at the Australian Institute of Marine Science (AIMS).The research, a collaboration between AIMS and CSIRO, drew on over a decade of observations collected as part of Australia's Integrated Marine Observing System (IMOS) to conclude that the Reef's rich carbonate seafloor is not buffering against ocean acidification as previously thought."Our research shows that acidification is rapidly changing the conditions that support the growth of coral on the Reef. It's never been more important to address ocean acidification in plans to manage the Reef," said Dr. Bronte Tilbrook, a Senior Principal Research Scientist at CSIRO who leads IMOS' observational projects for COOcean acidification results from seawater absorbing excess COWhile long-term data exist for COThe study has filled this important knowledge gap by analysing 10 years of COThe researchers found the minimum CO"We know now that oceans are taking up about 23% of the excess COIn another research first, AIMS and CSIRO scientists have used data from 1384 Reef sites to show coastal acidification's negative impacts on three important indicators of Reef health:The study, published earlier this year in the journal Global Change Biology, found these baby coral and coralline algae also decreased and seaweed increased as fine suspended sediment increased across the Reef -- with the greatest sediment concentration and organism changes observed closer to the shore. The researchers highlighted effective water quality management as an achievable solution to reduce coastal acidification's impact on the Reef.Australia's Integrated Marine Observing System (IMOS) is enabled by the National Collaborative Research Infrastructure Strategy (NCRIS). It is operated by a consortium of institutions as an unincorporated joint venture, with the University of Tasmania as Lead Agent.
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Climate
| 2,020 |
October 27, 2020
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https://www.sciencedaily.com/releases/2020/10/201027192412.htm
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Coastal Greenland reshaped as Greenland ice sheet mass loss accelerates
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Ice loss from the Greenland Ice Sheet has accelerated significantly over the past two decades, transforming the shape of the ice sheet edge and therefore coastal Greenland, according to scientific research led by Twila Moon, deputy lead scientist of the National Snow and Ice Data Center. These changes to the ice sheet could have far-reaching impacts on ecosystems and communities, as the flow of water under the ice sheet as well as nutrient and sediment flow are altered. Results of the research were published on October 27 in the American Geophysical Union's
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"The speed of ice loss in Greenland is stunning," said Moon. "We can now see many signs of a transformed landscape from space. And as the ice sheet edge responds to rapid ice loss, the character and behavior of the system as a whole is changing, with the potential to influence ecosystems and people who depend on them."The researchers compiled data from NASA, the United States Geological Survey, and other satellites from 1985 to 2015 to compare ice edge position, ice sheet surface elevation, and glacier flow over three decades. Advancements in satellite technology allowed them to observe the changes to the ice sheet in much greater detail than was possible in the past. Much of the data used was from the NASA Inter-mission Time Series of Land Ice Velocity and Elevation (ITS_LIVE) project, which facilitates ice sheet, ice shelf, and glacier research by providing a global record of land ice velocity and elevation derived from nearly three decades of satellite observations.Using these comparisons, the researchers developed a few key findings. The most consistent trend, found across the entire ice sheet, is widespread ice edge retreat. While there is a range of behavior among glaciers across the ice sheet, there is a noticeable lack of sustained ocean-connected glacier advance. Out of 225 ocean-connected glaciers that were measured, none have substantially advanced while 200 have retreated, particularly since 2000. This is notable even in regions dominated by slower-moving glaciers and cooler ocean water, such as the northern and northeastern regions of the ice sheet. In addition, while the vast majority of glaciers are retreating, ice flow response on those glaciers, such as speeding up or slowing down, is affected in large part by topography and upstream factors. This includes the slope of the landscape and the presence and shape of bedrock and sediments underneath the glacier. Therefore, even glaciers within the same regional or local area can behave differently.As the researchers examined changes in the Greenland Ice Sheet, they found that zones of fast glacier flow are narrowing, ice is being rerouted, and in some cases, the flow of new ice to glaciers is slowed, stranding glaciers in place. These processes could have a variety of downstream impacts, such as altering how water moves under the ice sheet, which could affect the availability of water to communities and animals, altering where nutrients and sediment enter the ocean, exposing new land areas, opening new fjord waters, and altering ecosystems and physical landscapes."As the Arctic ocean and atmosphere warm, we can clearly see the flow of ice into the ocean accelerate and the ice edge retreat," said Alex Gardner, a research scientist at NASA's Jet Propulsion Laboratory and co-author of the study. "When we look more closely, however, we can see the complexity of how individual glaciers respond, owing to differences in the properties of the ocean water that reach the glacier front, the bedrock and till that lie below, and in how meltwater runoff is routed beneath. Understanding the complexity of individual glacier response is critical to improving projections of ice sheet change and the associated sea level rise that will arrive at our shores."
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Climate
| 2,020 |
October 27, 2020
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https://www.sciencedaily.com/releases/2020/10/201027133731.htm
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Ice loss due to warming leads to warming due to ice loss: a vicious circle
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The loss of huge ice masses can contribute to the warming that is causing this loss and further risks. A new study now quantifies this feedback by exploring long-term if-then-scenarios. If the Arctic summer sea-ice were to melt completely, a scenario that is likely to become reality at least temporarily within this century with ongoing greenhouse gas emissions from burning fossil fuels, this could eventually add roughly 0.2°C to global warming. It is, however, not in addition to IPCC projections of future warming since these already take the relevant mechanisms into account. Still, the scientists could now separate the effects of the ice loss from other effects and quantify it.
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The 0.2°C are substantial, given that global mean temperature is currently about one degree higher than in pre-industrial times, and governments worldwide agreed to stop the increase well below two degrees."If global ice masses shrink, this changes how much of the sunlight that hits Earth's surface is reflected back into space. Decreasing ice cover in the Arctic exposes more of the darker ocean water that absorbs more energy," says Nico Wunderling, lead author of the study. "This is referred to as albedo feedback. It's like wearing white or black clothes in summer. If you wear dark, you heat up more easily." Further factors include for instance the increase of water vapour in the atmosphere due to the warming if more ice is melting. Warmer air can hold more water vapour, and water vapour increases the greenhouse effect. The basic mechanisms are well-known since long, but the Potsdam scientists were able to actually calculate the overall amount of warming that can be triggered by global ice loss."This is not a short-term risk. Earth's ice masses are huge, which makes them very important for our Earth system as a whole -- it also means that their response to anthropogenic climate change, especially that of the ice sheets on Greenland and Antarctica, unfolds on longer timescales. But even if some of the changes might take hundreds or thousands of years to manifest, it's possible we trigger them within just a couple of decades," says Ricarda Winkelmann who leads the research group.The scientists did comprehensive computer simulations. The effects are not always straightforward: for instance, if a massive ice cover on land is shrinking, there can still be snow -- which still reflects the sunlight, just like the ice did. This is why, if the mountain glaciers and the ice on Greenland and West Antarctica would all disappear, the additional warming directly caused by the ice loss would likely be just an additional 0.2 degrees on top of the 0.2 degrees due to Arctic summer sea-ice melting. "Yet every tenth of a degree of warming counts for our climate," says Winkelmann. "Preventing Earth system feedback loops, or vicious circles, is thus more urgent than ever."
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Climate
| 2,020 |
October 27, 2020
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https://www.sciencedaily.com/releases/2020/10/201027133729.htm
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Beaches can survive sea-level rises as long as they have space to move
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An international team of coastal scientists has dismissed suggestions that half the world's beaches could become extinct over the course of the 21st century.
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The claim was made by European researchers in a paper published in See 'World's sandy beaches under threat from climate change' at However, academics from the UK, France, South Africa, Australia, New Zealand and the USA have re-examined the data and methodology that underpinned the original study and say they strongly disagree with its conclusion.They have now published a rebuttal to the article in the same journal, and concluded that with the global data and numerical methods available today it is impossible to make such global and wide-reaching predictions.Critical to their disagreement with the original paper's conclusions is the fact that they say there is potential for beaches to migrate landwards as sea level rises and shorelines retreat.The key notion behind that is that if beaches have space to move into under the influence of rising sea levels -- referred to as accommodation space -- they will retain their overall shape and form but in a more landward position.The new research says that beaches backed by hard coastal cliffs and engineering structures, such as seawalls, are indeed likely to disappear in the future due to sea-level rise as these beaches are unable to migrate landward.They will first experience 'coastal squeeze' resulting in a decrease in width, and will eventually drown.However, beaches backed by low-lying coastal plains, shallow lagoons, salt marshes and dunes will migrate landward as a result of rising sea level. In these cases, the shoreline will retreat, but the beaches are still likely to remain, albeit a little raised in elevation and located landward, and will certainly not go 'extinct'.The new paper says there is currently no information available globally on the number of beaches which fall into either category and, as such, it is impossible to quantify what proportion of the world's beaches will disappear between now and 2100.Andrew Cooper, Professor of Coastal Studies at Ulster University and the new paper's lead author, said: "New methods are needed for predicting impacts of sea-level rise on the coast. This will require better datasets of coastal morphology and improved understanding of the mechanisms of shoreline response in given settings. As sea level rises, shoreline retreat must, and will, happen but beaches will survive. The biggest threat to the continued existence of beaches is coastal defence structures that limit their ability to migrate."Co-author Professor Gerd Masselink, from the University of Plymouth's Coastal Processes Research Group, led a study earlier this year which found that island 'drowning' is not inevitable as sea levels rise.He added: "Sea level is currently rising and will continue to rise at an increasing rate for many years to come. This will lead to more coastal erosion and it is crucial that we anticipate the future loss of land and take this into account in coastal management and planning to avoid putting more buildings and coastal infrastructure in harm's way. In the UK, Coastal Change Management Areas (CCMAs) are becoming increasingly important as a planning tool. CCMAs are areas that are likely to be affected by coastal change in the future and development in these areas should be avoided. This will then enable the coastline to respond naturally to sea-level rise, preventing coastal squeeze and loss of beaches."Coastal structures such as seawalls prevent beaches from naturally adjusting to rising sea levels by migrating landward and in those settings, removal of the structures (managed realignment) or nature-based solutions (beach nourishment) may be the only methods to safeguard the future of these beaches.
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Climate
| 2,020 |
October 27, 2020
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https://www.sciencedaily.com/releases/2020/10/201027111243.htm
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Photovoltaics industry can help meet Paris agreement targets
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To meet the Paris Agreement's daunting goal of preventing Earth's average temperature from rising more than 2 degrees Celsius (3.6 degrees Fahrenheit) above its level in preindustrial times, one of the best options for the energy economy will involve a shift to 100% renewable energy using solar energy and several other clean energy sources.
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While no one knows exactly how an increase above 2 degrees Celsius would impact the planet, extraordinary climatic events would likely make many parts of the world uninhabitable with significant desertification, ocean acidification, and rise of seawater level, as well as floods, wildfires, hurricanes, and tornadoes.In the "Our planet is on the path of an average temperature increase of 4 degrees Celsius before the end of this century, with respect to the average Earth temperature before the industrial age, and the result will be catastrophic," Verlinden said.Climate experts predict only 800 gigatons of carbon dioxide can be emitted before crossing the 2 degrees Celsius line. This means that at the current global emission of 36 gigatons per year, there is a 35-year window to reduce our emissions to zero.One way to achieve this goal is to change the way energy is produced and consumed."Our vision is solar photovoltaics can play a central role in a transformed sustainable energy economy with 100% decarbonized electricity generation to power directly or indirectly -- through the production of green hydrogen or other synthetic fuels -- all energy sectors and industrial processes," said Verlinden.The world will require, in addition to other renewable energy sources like wind and hydro, about 70 to 80 terawatts of cumulative capacity from solar photovoltaic systems. This represents more than 100 times the world's current solar photovoltaic installed capacity."Within the next 10 years, the industry needs to increase its production rate by a factor of about 30," he said.A model developed by Verlinden and colleagues to predict the efficiency of solar cells and their cost to manufacture during the next few decades shows there "is no fundamental barrier to achieving this goal," he said.The financial requirement to grow the production rate (capital expenditures to build new production lines) is decreasing at a rate of 18% per year, driven by productivity improvements and a combination of higher-throughput per tool, larger wafers, and improved cell efficiency."In terms of material sustainability, the only major issue is the use of silver for metallization of silicon solar cells," said Verlinden. "We need to reduce the use of silver in silicon solar cells from about 29 tons per gigawatt to less than 5 tons per gigawatt."He cautions that while the objective of a cumulative installation of 70 or 80 terawatts by 2055 is achievable with a simple annual growth of the production rate of about 15% per year, pursuing this goal will result in a solar photovoltaic industry much larger than necessary. This could lead to a significant downturn when the objective of 80 terawatts is reached."This negative impact can be avoided if we right now accelerate the growth during the next 10 years and then stabilize the global production to 3 to 4 terawatts per year," Verlinden said.
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October 27, 2020
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https://www.sciencedaily.com/releases/2020/10/201027105342.htm
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Back to the future of climate
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Between 57 and 55 million years ago, the geological epoch known as the Paleocene ended and gave way to the Eocene. At that time, the atmosphere was essentially flooded by the greenhouse gas carbon dioxide, with concentration levels reaching 1,400 ppm to 4,000 ppm. So it's not hard to imagine that temperatures on Earth must have resembled those of a sauna. It was hot and humid, and the ice on the polar caps had completely disappeared.
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The climate in that era provides researchers with an indication as to how today's climate might develop. While pre-industrial levels of atmospheric COUsing tiny siderite minerals in soil samples taken from former swamps, a group of researchers from ETH Zurich, Pennsylvania State University and CASP in Cambridge (UK) reconstructed the climate that prevailed at the end of the Paleocene and in the early Eocene. Their study has just been published in the journal The siderite minerals formed in an oxygen-free soil environment that developed under dense vegetation in swamps, which were abundant along the hot and humid coastlines in the Paleocene and Eocene.To reconstruct the climatic conditions from the equator to the polar regions, the researchers studied siderites from 13 different sites. These were all located in the northern hemisphere, covering all geographical latitudes from the tropics to the Arctic."Our reconstruction of the climate based on the siderite samples shows that a hot atmosphere also comes with high levels of moisture," says lead author Joep van Dijk, who completed his doctorate in ETH Professor Stefano Bernasconi's group at the Geological Institute from 2015 to 2018.Accordingly, between 57 and 55 million years ago, the mean annual air temperature at the equator where Colombia lies today was around 41 °C. In Arctic Siberia, the average summer temperature was 23 °C.Using their siderite "hygrometer," the researchers also demonstrated that the global moisture content in the atmosphere, or the specific humidity, was much higher in the Paleocene and Eocene eras than it is today. In addition, water vapour remained in the air for longer because specific humidity increased at a greater rate than evaporation and precipitation. However, the increase in specific humidity was not the same everywhere.Since they had access to siderite from all latitudes, the researchers were also able to study the spatial pattern of the specific humidity. They found that the tropics and higher latitudes would have had very high humidity levels.The researchers attribute this phenomenon to water vapour that was transported to these zones from the subtropics. Specific humidity rose the least in the subtropics. While evaporation increased, precipitation decreased. This resulted in a higher level of atmospheric water vapour, which ultimately reached the poles and the equator. And the atmospheric vapour carried heat along with it.Climate scientists still observe the flow of water vapour and heat from the subtropics to the tropics today. "Latent heat transport was likely to have been even greater during the Eocene," van Dijk says. "And the increase in the transport of heat to high latitudes may well have been conducive to the intensification of warming in the polar regions," he adds.These new findings suggest that today's global warming goes hand in hand with increased transport of moisture, and by extension heat, in the atmosphere. "Atmospheric moisture transport is a key process that reinforces warming of the polar regions," van Dijk explains."Although the COFinding the siderites was not easy. For one thing, the minerals are tiny, plus they occur solely in fossil swamps, which today are often found only several kilometres below the Earth's surface. This made it difficult or even impossible for the researchers to dig up siderites themselves. "We made several expeditions to sites where we believed siderites might occur but we found them at only one of those locations," van Dijk says.Fortunately, one of the study's co-authors -- Tim White, an American from Pennsylvania State University -- owns the world's largest collection of siderite.
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October 27, 2020
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https://www.sciencedaily.com/releases/2020/10/201027105339.htm
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Small mussels in the Baltic are getting even smaller
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Blue mussels in the Baltic Sea are getting smaller with time but bigger in numbers, according to a new study from Stockholm University. Analyzing data from the last 24 years, the main reason for this appears to be changes in food quality. The type of phytoplankton that is available for blue mussels to eat can in turn be linked to our changing climate.
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Blue mussels in the Baltic Sea are already small in their nature -- the length of the mussels is about the length of a nail to the mere eye. In this study, the researchers discovered that blue mussels are now weighing around half of what they used to weigh in the 90's, despite the mean length difference just being a few millimeters. But on the other hand there are now more mussels that are really tiny, sometimes as many as 1000 in one square meter compared to about 500 per square meter before.Mussels compose the largest biomass of animals without a backbone in the Baltic, providing food to eider ducks and fish, for example. But because they are getting 'smaller' it means less food for the species feeding on them. It is also estimated that all blue mussels in the Baltic, together filter the entire waters of Baltic sea every year -- and this is essential for cleaning the water from particles and helping to combat eutrophication -- one of the Baltics biggest threats. Since the mussel size is affected it might therefore have effects on filtration rates, although this was not tested in this particular study:"Even though an increase in the number of mussels to some extent may compensate for the smaller size, it is likely that important functions like filtration of the water has been reduced, which could lead to more turbid water" says Agnes Karlsson, Assistant Professor at Department of Ecology, Environment and Plant Sciences (DEEP) at Stockholm University.The reason for the mussels getting smaller is likely altered mix of phytoplankton, now with greater quantities of cyanobacteria and particles from land. Warmer waters favour cyanobacteria, in turn causing increased summer blooms. Yet, the study found no direct role of increasing temperature for the decrease in mussel size. This means that indirect effects of climate change might be more important for mussels. The study is based on continuously monitored and collected samples of both mussels and phytoplankton from 1993 to 2016:"We want to call attention to the benefits of long-term monitoring. If not for monitoring, we wouldn't have known that this key species for the Baltic is on a slippery slope," says Agnes Karlsson, Assistant Professor at Department of Ecology, Environment and Plant Sciences (DEEP) at Stockholm University.The study highlights the importance of keeping an eagle eye perspective when considering how environmental changes affect key-organism in the long-run:"There is often multiple and interacting factors responsible for changes in an organisms' condition or population and all of this likely affects the entire ecosystem functioning" says Camilla Liénart, postdoc at Department of Ecology, Environment and Plant Sciences (DEEP) at Stockholm University.
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October 27, 2020
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https://www.sciencedaily.com/releases/2020/10/201027105337.htm
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Saving the climate from the ground up
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Soil has the capacity to bind large quantities of carbon in the long term. An international team of researchers, including from the University of Bonn, is now advocating effective use of this potential. Experts estimate that this could reduce the increase of the greenhouse gas carbon dioxide in the atmosphere by a third. At the same time, agricultural yields in many regions would also increase significantly. In a recent publication they present a strategy to achieve these goals. The study is published in the journal
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The climate summit in Paris in 2015 was also the birth of the so-called "4 per 1,000" initiative. Its name stands for a link that has not received enough attention in climate research and politics for a long time: Every year the amount of carbon in the atmosphere increases by more than four billion tons due to the human-made greenhouse gas COExperts are indeed confident today that this strategy could significantly slow down climate change. "0.4 percent additional carbon input is somewhat too optimistic," explains Prof. Wulf Amelung, who heads the Division of Soil Science at the University of Bonn. "However, a third of this is probably achievable." Nevertheless, little has changed since 2015. Together with colleagues from Europe, the USA, Australia and China, Amelung and colleagues therefore want to put the issue back on the agenda. In the current issue of the journal There are a number of simple measures to increase the amount of carbon in the soil, such as mulching (i.e. covering the soil with crop residues) or adding plant-based coal. The most important method, however, is to increase plant growth (and thus crop yields): by liming acidic soils, by fertilizing as needed, by using smart irrigation. "The more grows on the soil, the better is it rooted," explains Amelung. "And roots with their widely branching networks of organic material store lots of carbon." Conversely, the organic matter contains essential nutrients for plant growth and thus promotes crop yield. "Our strategy therefore ultimately addresses two important goals: climate protection and food security."However, the global implementation of this ambitious plan is not quite so simple: The quality and characteristics of soils in different locations are too different, and the available management technologies are too dissimilar. "Increasing the carbon input therefore requires locally adapted measures; we need completely different strategies in the rice-growing regions of Asia than, for example, on a cereal field in northern Germany," Amelung emphasizes. In addition, many carbon sequestration measures are particularly effective when soils are partially degraded by long-term overuse and have lost a lot of carbon. "From a cost-benefit perspective, it certainly makes the most sense to start on such areas, not least because the yield increases are likely to be greatest there," explains the soil expert.Unfortunately, however, knowledge about the condition of soil is very patchy. The researchers therefore recommend the establishment of databases that record the condition of land around the globe on a very small scale, as well as an equally small-scale modeling of possible yield gains and the necessary use of fertilizers. It must furthermore be ensured that there is no mere redistribution of carbon inputs: for example, organic material is moved from one farm to another at great expense and is now missing at its place of origin.
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October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026184029.htm
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Healthcare as a climate solution
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Although the link may not be obvious, healthcare and climate change -- two issues that pose major challenges around the world -- are in fact more connected than society may realize. So say researchers, who are increasingly proving this to be true.
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Case in point: A new study by UC Santa Barbara's Andy MacDonald found that improving healthcare in rural Indonesia reduced incentives for illegal logging in a nearby national park, averting millions of dollars' worth of atmospheric carbon emissions.The analysis, published in the "The results illustrate a strong link between human health and conservation in tropical forests in the developing world," said MacDonald, an assistant researcher at the Earth Research Institute who coauthored the study with UC Santa Barbara's David Lopez-Carr and colleagues at Stanford University, North Carolina State University Raleigh, Oregon Health and Science University, Natural Capital Advisors, and two NGOs involved in the intervention.The Indonesian clinic accepts barter as payment and gives discounts to villages based on community-wide reductions in logging. Given its success, it could provide a blueprint for preserving the world's biodiverse carbon sinks while reducing poverty and illness."This innovative model has clear global health implications," said coauthor Michele Barry, senior associate dean of global health at Stanford and director of the Center for Innovation in Global Health. "Health and climate can and should be addressed in unison, and done in coordination with and respect for local communities."Every second, more than 100 trees disappear from tropical forests around the world. These forests, some of the world's most important carbon reservoirs, are crucial to slowing climate change and mass extinction.The current paradigm for conserving tropical forests -- establishing protected areas -- often excludes and disenfranchises local communities. This failure to address people's needs can lead communities with few economic alternatives to illegally log and convert the land. Lack of access to high-quality, affordable healthcare can compound the problem by perpetuating cycles of poor health and expanding out-of-pocket costs.With this in mind, the nonprofit organizations Alam Sehat Lestari and Health In Harmony in 2007 established a healthcare clinic adjacent to Gunung Palung National Park in West Kalimantan, Indonesia, with the support of the local government. The clinic was able to serve thousands of patients by accepting a range of alternative payments, such as tree seedlings, handicrafts and labor -- an approach that was created in collaboration with the communities themselves.Through agreements with most of the region's district leaders, the clinic also provided discounts to villages that could show evidence of reductions in illegal logging. Between 1985 and 2001, this region had lost 60% of its forest to this activity. In addition to affordable health care, the intervention provided training in sustainable, organic agriculture and a chainsaw buyback program.Researchers worked with the two non-profits to analyze more than 10 years of the clinic's patient health records, coupled with satellite observations of forest cover over that time. "Private foundations funded the interventions, but it's innovative new programs at Stanford and the University of California that are funding the research," MacDonald said.The medical care led to a significant decline in a range of diseases such as malaria, tuberculosis and diabetes. At the same time, satellite images of the national park showed a 70% reduction in deforestation, compared to forest loss at control sites, an amount equivalent to more than 6,770 acres of rainforest."We didn't know what to expect when we started evaluating the program's health and conservation impacts, but we were continually amazed that the data suggested such a strong link between improvements in healthcare access and tropical forest conservation," said lead author Isabel Jones, who recently earned her doctorate in biology at Stanford. Looking more closely at community-level logging rates, the researchers found that the greatest drop-offs in logging occurred adjacent to villages with the highest rates of clinic usage."This is a case study of how to design, implement and evaluate a planetary health intervention that addresses human health and the health of rainforests on which our health depends," said coauthor Susanne Sokolow, a senior research scientist at Stanford.Globally, about 35% of protected areas are traditionally owned, managed, used or occupied by Indigenous and local communities. Yet the perspective and guidance of Indigenous peoples and local communities are rarely considered in the design of conservation and climate mitigation programs. By contrast, the Indonesian clinic's success grew out of the early and continued input of local communities who identified the mechanisms driving health and environmental problems as well as possible solutions.Such holistic approaches can have greater long-term effects by preserving and restoring the ecosystem services that protect human health. These include natural filtering processes that reduce the risk of waterborne diseases and shade-providing forest canopies that reduce ground temperature and heat-related illnesses."The data support two important conclusions: human health is integral to the conservation of nature and vice versa, and we need to listen to the guidance of rainforest communities who know best how to live in balance with their forests," said Monica Nirmala, the executive director of the clinic from 2014 to 2018 and current board member of Health In Harmony.The clinic in West Kalimantan is still active, and the researchers are currently working on a follow-up project to see whether it and similar interventions in Indonesia have alleviated some of the shock from COVID-19 both on human health and deforestation."We would expect illegal logging activity to respond to changes in timber market prices or loss of income associated with COVID-19," MacDonald said. "We want to know whether the interventions buffered communities against these effects, as well as whether they increased the communities' resilience in terms of health and wellbeing."Health in Harmony is also expanding to Madagascar and Brazil," he added, "and we want to be able to robustly evaluate the impacts of their interventions there."
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Climate
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October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026164427.htm
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Sea-level rise global observing system proposed
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University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science researcher Shane Elipot proposes a new approach to monitoring global sea-level rise. Using the existing NOAA Global Drifter Program array of roughly 1,200 buoys that drift freely with ocean currents, Elipot suggests adding additional instruments to record their height, or the "level of the sea" they ride on, to collect long-term data on the average sea levels across the world's oceans.
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Elipot's research, published in the American Geophysical Union's journal "Sea-level rise is a serious threat to our society, especially in coastal areas like Miami," said Elipot, a research assistant professor of ocean sciences. "While tremendous advances have been made in understanding the exact causes of sea level, continuing and resilient monitoring of sea level is necessary for planning and management at local and global scales."Elipot has secured a research contract with the NASA Jet Propulsion Laboratory to conduct a pilot project to construct buoys that will record their heights as they drift. This pilot project will be conducted with colleagues from NOAA's Atlantic Oceanographic Meteorological Laboratory and Scripps Institution of Oceanography at UC San Diego. These drifters will be built at Scripps and tested off both the UM Rosenstiel School and Scripps piers.
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October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026135744.htm
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US corn crop's growing sensitivity to drought revealed
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Like a baseball slugger whose home run totals rise despite missing more curveballs each season, the U.S. Corn Belt's prodigious output conceals a growing vulnerability. A new Stanford study reveals that while yields have increased overall -- likely due to new technologies and management approaches -- the staple crop has become significantly more sensitive to drought conditions. The research, published Oct. 26 in
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"The good news is that new technologies are really helping to raise yields, in all types of weather conditions," said study lead author David Lobell, the Gloria and Richard Kushel Director of the Center on Food Security and the Environment. "The bad news is that these technologies, which include some specifically designed to withstand drought, are so helpful in good conditions that the cost of bad conditions are rising. So there's no sign yet that they will help reduce the cost of climate change."Corn production in the U.S. is a seemingly unstoppable juggernaut. Despite concerns about resistant weeds, climate change and many other factors, the industry has set record yields in five of the last seven years. Likely drivers of these bumper crops include changes in planting and harvesting practices, such as adoption of drought-tolerant varieties, and changes in environmental conditions, such as reduced ozone levels and increased atmospheric carbon dioxide concentrations that generally improve the water-use efficiency of crops.As climate change intensifies, however, the cost to maintain crop yields will likely increase.Using county soil maps and satellite-based yield estimates, among other data, the researchers examined fields in the Corn Belt, a nine-state region of the Midwest that accounts for about two-thirds of U.S. corn production. By comparing fields along gradients of drought stress each year, they could identify how sensitivity to drought is changing over time.Even within a single county, they found a wide range of soil moisture retention, with some soils able to hold twice as much water as others. As might be expected, there were generally higher yields for soils that held more water. They found yield sensitivity to soil water storage in the region increased by 55 percent on average between 1999 and 2018, with larger increases in drier states.The results made clear soil's ability to hold water was the primary reason for yield loss. In some cases, soil's ability to hold an increased amount of moisture was three times more effective at increasing yields than an equivalent increase in precipitation.So, why have yields become more sensitive to drought? A variety of factors, such as increased crop water needs due to increased plant sowing density may be at play. What is clear is that despite robust corn yields, the cost of drought and global demand for corn are rising simultaneously.To better understand how climate impacts to corn are evolving over time, the researchers call for increased access to field-level yield data that are measured independently of weather data, such as government insurance data that were previously available to the public but no longer are."This study shows the power of satellite data, and if needed we can try to track things from space alone. That's exciting," Lobell said. "But knowing if farmers are adapting well to climate stress, and which practices are most helpful, are key questions for our nation. In today's world there's really no good reason that researchers shouldn't have access to all the best available data to answer these questions."Lobell is also a professor of Earth System Science in Stanford's School of Earth, Energy & Environmental Sciences; the William Wrigley Senior Fellow at the Stanford Woods Institute for the Environment and a senior fellow at the Freeman Spogli Institute for International Studies and the Stanford Institute for Economic Policy Research. Study co-authors include Jillian Deines, a postdoctoral research fellow in Stanford's School of Earth, Energy & Environmental Sciences, and Stefania Di Tommaso, a research data analyst at the Center on Food Security and the Environment.
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Climate
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October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026114231.htm
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Land management in forest and grasslands: How much can we intensify?
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Ecosystem services are crucial for human well-being and they depend on a well-functioning ecosystem and complex interactions among many organisms. However, human activities are resulting in biodiversity loss and changes to ecosystems, which threatens the supply of key services. An international team of 32 scientists, from 22 institutions, led by Dr Maria Felipe-Lucia (UFZ, iDiv) and Prof Eric Allan (University of Bern) now present the very first assessment of the simultaneous effects of land-use intensity on biodiversity, ecosystem functions, and services.
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The researchers investigated how these interactions vary with land-use intensity. They analysed data from 300 German grasslands and forests, varying in land-use intensity, and borrowed approaches from network analysis to characterize the overall relationships between biodiversity, ecosystem functions and services."We already knew that land use affects biodiversity and ecosystem functioning," says the lead author of the paper Dr Felipe-Lucia, senior scientist at UFZ and iDiv. "But we knew very little about how land-use intensity simultaneously alters the relationships between diversities, functions and services. By understanding these relationships, we can anticipate how future changes in land use will affect ecosystems and human wellbeing."We cannot intensify without limits: varied landscapes are the keyThe study demonstrates that low intensity farming and forestry can provide material benefits (fodder, timber), while preserving biodiversity. In contrast, high intensity practices increase material benefits but reduce biodiversity and the benefits people derive from it."With increasing land-use intensity we are losing specialized relationships," Felipe-Lucia concludes. "This is comparable to shopping either in a low-quality mega-store or in a specialized boutique." Similar to specialized boutiques, where it is necessary to visit many different of them to get the best items, low land-use intensity grasslands and forests are specialized in a particular set of biodiversity, functions and associated services. High land-use intensity landscapes are comparable to mega-stores where all kinds of goods can be found at one place, but of lower quality."As in any city, it is ok to have a couple of mega-stores, but we cannot neglect the smaller high-quality boutiques either. In our landscapes, we need to maintain pockets of low land-use intensity to provide these specialized gifts," explains Allan, senior athour of the paper.In healthy ecosystems, more species usually means higher levels of ecosystem services for people and therefore better human wellbeing. "Intensification tends to homogenize biodiversity-functioning-service relationships and lead to a less integrated system with fewer positive relations between services," points out Allan. "Diverse low intensity systems can provide different sets of services and a varied landscape could therefore be the key to solve conflicting land uses and provide a wider range of services while preserving biodiversity.""We also identified the level of management intensity that disrupts the normal functioning of the landscape, that is, when the ecosystem becomes more dependent on human inputs (such as fertilizer) for its functioning," says Felipe-Lucia.The new analyses can help to detect the loss of correlations between biodiversity and ecosystem services, which could be taken as an early warning signal of ecosystem change. "Our approach provides a new and comprehensive view of ecosystem functioning and can identify the key ecosystem attributes to monitor in order to prevent critical shifts in ecosystems," says Allan. "It can also be applied to analyze the effects of other global changes such as climate change."
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Climate
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October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026114214.htm
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The uncertain future of the oceans
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The ocean plays a key role in the current climate change, as it absorbs a considerable part of the atmospheric carbon dioxide emitted by humankind. On the one hand, this slows down the heating of the climate, and on the other hand, the dissolution of CO
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The study, which has now been published in the journal Dr. Jan Taucher, marine biologist and main author of the study, says: "Interestingly, we found that bacterial and animal plankton, such as small crustaceans, play a key role in how the carbon cycle and biological pump respond to ocean acidification. Until now, it has been widely held that biogeochemical changes are mainly driven by reactions of phytoplankton. Therefore, even modern Earth system models do not take into account the interactions we observe between the marine food web and the carbon cycle. Our findings thus help to make climate models more realistic and improve climate projections."Up to now, most of the knowledge on this topic has been based on idealized laboratory experiments, which only represent ecological interactions and the dynamics of the complex marine food web in a highly simplified way. This makes it difficult to transfer such results to real ocean conditions and project them into the future. In order to gain a more realistic insight, the study summarizes several field experiments that were conducted with large-volume test facilities, so-called mesocosms, in different ocean regions, from arctic to subtropical waters.Mesocosms are, so to speak, oversized test tubes in the ocean, in which changes in environmental conditions in a closed but otherwise natural ecosystem can be studied. For the present study, a large amount of data from five mesocosm experiments was synthesized to provide a more precise picture of plankton communities and biogeochemical processes within the ecosystem. A total of over ten thousand data points were included in the analysis.The newly gained knowledge can now be used to implement the complex ecological interactions in Earth system models, thus contributing to further improve climate projections.
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Climate
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October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026095433.htm
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Irregular appearances of glacial and interglacial climate states
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During the last 2.6 million years of Earth's climate has altered between glacial and interglacial states. As such, there have been times in which the transition between the two climate states appeared with either regular or irregular periodicity. AWI researcher Peter Köhler has now discovered that the irregular appearance of interglacials has been more frequent than previously thought. His study makes a significant contribution to our understanding of Earth's fundamental climate changes.
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In order to understand human beings' role in the development of our current climate, we have to look back a long way, since there has always been climate change -- albeit over vastly different timescales than the anthropogenic climate change, which is mainly due to the use of fossil fuels over the past 200 years. Without humans, for millions of years, climate altered between glacial and interglacial states over periods of many thousands of years, mainly because of the Earth's tilt which changes by a few degrees with a periodicity of 41,000 years. This in turn changes the angle at which the sun's rays strike Earth -- and as such the energy that reaches the planet, especially at high latitudes in summer. However, there is strong evidence that during the course of the last 2.6 million years, interglacials have repeatedly been 'skipped'. The Northern Hemisphere -- particularly North America -- remained frozen for long periods, despite the angle of the axial tilt changing to such an extent that more solar energy once again reached Earth during the summer, which should have melted the inland ice masses. This means Earth's tilt can't be the sole reason for Earth's climate to alter between glacial and interglacial states.In order to solve the puzzle, climate researchers are investigating more closely at what points in Earth's history irregularities occurred. Together with colleagues at Utrecht University, physicist Peter Köhler from the Alfred Wegener Institute (AWI) has now made a significant contribution towards providing a clearer picture of the sequence of glacial and interglacial periods over the last 2.6 million years. Until now, experts thought that, especially over the past 1.0 million years, glacial and interglacial periods deviated from their 41,000- year cycle, and that interglacial periods were skipped, as a result of which some glacial periods lasted for 80,0000 or even 120,000 years. "For the period between 2.6 and 1.0 million years ago, it was assumed that the rhythm was 41,000 years," says Peter Köhler. But as his study, which has now been published in the scientific journal Köhler's study is particularly interesting because he re-evaluated a well-known dataset that researchers have been using for several years -- the LR04 climate dataset -- yet arrived at completely different conclusions. This dataset consists of a global evaluation of core samples from deep-sea sediments that are millions of years old, and includes measurements from the ancient shells of microscopic, single-celled marine organisms -- foraminifera -- that were deposited on the ocean floor. Foraminifera incorporate oxygen from the seawater into their calcium shells. But over millennia, the level of specific oxygen isotopes -- oxygen atoms that have differing numbers of neutrons and therefore different masses -- varies in seawater.The LR04 dataset contains measurements of the ratio of the heavy oxygen isotope 18O to the lighter 16O. The ratio of 18O/16O stored in the foraminifera's shells depends on the water temperature. But there is also another effect that leads to relatively large amounts of 18O being found in the foraminifera's shells in glacial periods: when, during the course of a glacial period, there is heavy snowfall on land, which leads to the formation of thick ice sheets, the sea level falls -- in the period studied, by as much as 120 m. Since 18O is heavier than 16O, water molecules containing this heavy isotope evaporate less readily than molecules containing the lighter isotope. As such, comparatively more 18O remains in the ocean and the 18O content of the foraminifera shells increases. "If you take the LR04 dataset at face value, it means you blur two effects -- the influence of ocean temperature and that of land ice, or rather that of sea level change," says Peter Köhler. "This makes statements regarding the alternation of the glacial periods uncertain." And there is an additional factor: climate researchers mainly determine the sequence of glacial periods on the basis of glaciation in the Northern Hemisphere. But using 18O values doesn't allow us to say whether prehistoric glaciation chiefly occurred in the Northern Hemisphere or in Antarctica.In an attempt to solve this problem, Köhler and his team evaluated the LR04 dataset in a completely different way. The data was fed into a computer model that simulates the growth and melting of the large continental ice sheets. What sets it apart: the model is capable of separating the influence of temperature and that of sea level change on the 18O concentration. Furthermore, it can accurately analyse where and when snow falls and the ice increases -- more in the Northern Hemisphere or in Antarctica. "Mathematicians call this separation a deconvolution," Köhler explains, "which our model is capable of delivering." The results show that the sequence of glacials and interglacials was irregular even in the period 2.6 to 1.0 million years ago -- a finding that could be crucial in the coming years. As part of the ongoing major EU project 'BE-OIC (Beyond EPICA Oldest Ice Core)', researchers are drilling deeper than ever before into the Antarctic ice. With the oldest ice core recovered to date, 'EPICA', they have 'only' travelled back roughly 800,000 years into the past. The ancient ice provides, among other things, information on how much carbon dioxide Earth's atmosphere contained at that time. With 'Beyond EPICA' they will delve circa 1.5 million years into the past. By combining the carbon dioxide measurements with Köhler's analyses, valuable insights can be gained into the relation between these two factors -- the fluctuations in the sequence of glacials and the carbon dioxide content of the atmosphere. And this can help us understand the fundamental relationship between greenhouse gases and climate changes in Earth's glacial history.
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Climate
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October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026095402.htm
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Shifts in flowering phases of plants due to reduced insect density
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It still sounds unlikely today, but declines in insect numbers could well make it a frequent occurrence in the future: fields full of flowers, but not a bee in sight.
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A research group of the University of Jena (Germany) and the German Centre for Integrative Biodiversity Research Halle-Jena-Leipzig (iDiv) has discovered that insects have a decisive influence on the biodiversity and flowering phases of plants. If there is a lack of insects where the plants are growing, their flowering behaviour changes. This can result in the lifecycles of the insects and the flowering periods of the plants no longer coinciding. If the insects seek nectar at the wrong time, some plants will no longer be pollinated.Ecosystems are changing around the world, in particular due to global warming and altered land use. Insect species are dying out and the insect biomass is decreasing. Researchers have therefore studied how the biodiversity of plants is changing in the context of climate change. For this purpose, various climate scenarios have been simulated, using different temperatures and precipitation.In a new study reported in the specialist journal "We know that the insect biomass is decreasing," says Josephine Ulrich, a doctoral candidate from Römermann's team, referring to a study from 2017 which detected that insects had declined by 75 per cent over the previous 30 years.The Jena research group has now studied in detail for the first time the extent to which decreasing insect density influences plant development. Whereas previous studies had only carried out field experiments, the research team used the "Ecotron," an iDiv research facility where identical climatic situations can be simulated in artificial ecosystems and observed with cameras.In their experiment, the researchers studied how plant composition and plant development change if the number of insects falls by three-quarters.Ulrich and her colleagues discovered that the reduced insect biomass brings about a change in plant species. It is especially the dominant plant species, such as red clover, which become more prevalent. The development of the flowering period also changes as insect density declines. Some of the plants studied flowered earlier and others later."These changes can lead to mismatches between plant and animal species, which lead to adverse consequences for the ecosystem," says Ulrich, the lead author of the study. Examples are the food supply of insects and pollination success. This deterioration in the ecosystem function could entail further losses of insect and plant species. An additional consequence could be that plants become increasingly infested with pests. Due to the falling numbers of insects that feed on aphids, for example, these pests could spread unchecked.
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Climate
| 2,020 |
October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026081451.htm
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Uncertainties key to balancing flood risk and cost in elevating houses
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What do you have on your 2020 Bingo Card? Wildfire, heat wave, global pandemic, or flooding? If it's flooding, then it's a good bet it will happen in many places in the U.S. sometime during the year.
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People who live in areas designated as river flood zones often seek to raise their homes. Now a team of Penn State researchers suggests that considering uncertainties can improve decisions."Many houses located along rivers in Pennsylvania are in danger of being flooded," said Klaus Keller, professor of geosciences. "Some houses are elevated high, some to intermediate levels, and some not at all. Why is this?"People in river flood zones are looking for good strategies on how high to elevate their houses. The Federal Emergency Management Agency -- FEMA -- recommends elevating houses to the height of a flood that has a 1% chance to occur in a given year, also known as the 100-year flood, plus at least one foot. This is the minimum elevation for which federal funding may be available. The researchers investigated if they might improve on this suggested elevation given uncertainties surrounding, for example, future flooding, the future value of money and the vulnerability of a house to flooding. They reported their results today (Oct. 26) in "Looking at the range of possible outcomes can help to improve decisions on how high to elevate a house," said Mahkameh Zarekarizi, former Penn State postdoctoral fellow, now a hydroclimate scientist at Jupiter Intelligence. "It is arguably better to fail in a computer model than in real life. In the computer, we can look at many possible future outcomes of flooding, costs and other uncertainties."Decision makers may want to reduce the probability of being flooded and reduce the net costs."The decision makers may benefit from a map that shows the trade-offs between these goals," said Vivek Srikrishnan, assistant research professor, Earth and Environmental Systems Institute. "Home owners may want to see, for example, the total net price of reducing the risk of being flooded. A single recommendation such as the 100-year flood height plus at least one foot is silent on this question."The National Oceanic and Atmospheric Administration, Climate Program Office; The Penn State Initiative for Resilient Communities; the Center for Climate Risk Management; Penn State's Rock Ethics Institute; Penn State Law and Penn State's Hamer Center for Community Design supported this work.
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Climate
| 2,020 |
October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026081511.htm
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Globalized economy making water, energy and land insecurity worse
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The first large-scale study of the risks that countries face from dependence on water, energy and land resources has found that globalisation may be decreasing, rather than increasing, the security of global supply chains.
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Countries meet their needs for goods and services through domestic production and international trade. As a result, countries place pressures on natural resources both within and beyond their borders.Researchers from the University of Cambridge used macroeconomic data to quantify these pressures. They found that the vast majority of countries and industrial sectors are highly exposed both directly, via domestic production, and indirectly, via imports, to over-exploited and insecure water, energy and land resources. However, the researchers found that the greatest resource risk is due to international trade, mainly from remote countries.The researchers are calling for an urgent enquiry into the scale and source of consumed goods and services, both in individual countries and globally, as economies seek to rebuild in the wake of Covid-19. Their study, published in the journal Over the past several decades, the worldwide economy has become highly interconnected through globalisation: it is now not uncommon for each component of a particular product to originate from a different country. Globalisation allows companies to make their products almost anywhere in the world in order to keep costs down.Many mainstream economists argue this offers countries a source of competitive advantage and growth potential. However, many nations impose demands on already stressed resources in other countries in order to satisfy their own high levels of consumption.This interconnectedness also increases the amount of risk at each step of a global supply chain. For example, the UK imports 50% of its food. A drought, flood or any severe weather event in another country puts these food imports at risk.Now, the researchers have quantified the global water, land and energy use of189 countries and shown that countries which are highly dependent on trade are potentially more at risk from resource insecurity, especially as climate change continues to accelerate and severe weather events such as droughts and floods become more common."There has been plenty of research comparing countries in terms of their water, energy and land footprints, but what hasn't been studied is the scale and source of their risks," said Dr Oliver Taherzadeh from Cambridge's Department of Geography. "We found that the role of trade has been massively underplayed as a source of resource insecurity -- it's actually a bigger source of risk than domestic production."To date, resource use studies have been limited to certain regions or sectors, which prevents a systematic overview of resource pressures and their source. This study offers a flexible approach to examining pressures across the system at various geographical and sectoral scales."This type of analysis hasn't been carried out for a large number of countries before," said Taherzadeh. "By quantifying the pressures that our consumption places on water, energy and land resources in far-off corners of the world, we can also determine how much risk is built into our interconnected world."The authors of the study linked indices designed to capture insecure water, energy, and land resource use, to a global trade model in order to examine the scale and sources of national resource insecurity from domestic production and imports.Countries with large economies, such as the US, China and Japan, are highly exposed to water shortages outside their borders due to their volume of international trade. However, many countries in sub-Saharan Africa, such as Kenya, actually face far less risk as they are not as heavily networked in the global economy and are relatively self-sufficient in food production.In addition to country-level data, the researchers also examined the risks associated with specific sectors. Surprisingly, one of the sectors identified in Taherzadeh's wider research that had the most high-risk water and land use -- among the top 1% of nearly 15,000 sectors analysed -- was dog and cat food manufacturing in the USA, due to its high demand for animal products."Covid-19 has shown just how poorly-prepared governments and businesses are for a global crisis," said Taherzadeh. "But however bad the direct and indirect consequences of Covid-19 have been, climate breakdown, biodiversity collapse and resource insecurity are far less predictable problems to manage -- and the potential consequences are far more severe. If the 'green economic recovery' is to respond to these challenges, we need radically rethink the scale and source of consumption."
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Climate
| 2,020 |
October 23, 2020
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https://www.sciencedaily.com/releases/2020/10/201023141009.htm
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Coastal permafrost more susceptible to climate change than previously thought
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If you flew from the sea towards the land in the north slope of Alaska, you would cross from the water, over a narrow beach, and then to the tundra. From the air, that tundra would look like a landscape of room-sized polygonal shapes. Those shapes are the surface manifestations of the ice in the frozen ground below, a solidified earth known as permafrost.
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Scientists long believed the solid permafrost extended offshore: from the tundra, below that narrow beach and below the seafloor declining at a gentle slope. They viewed that permafrost like solid brick, locking the subsurface -- and the vast amounts of carbon it holds -- in place.But new research led by Micaela Pedrazas, who earned her masters at The University of Texas at Austin Jackson School of Geosciences working with Professor Bayani Cardenas, has upended that paradigm. They found permafrost to be mostly absent throughout the shallow seafloor along a coastal field site in northeastern Alaska. That means carbon can be released from coastline sources much more easily than previously thought.The study was published in Using a geophysical technique called electrical resistivity imaging, the researchers mapped the subsurface beneath Kaktovik Lagoon along the northeastern coast of Alaska over the course of three years.The results were unexpected. The beach and seafloor were entirely ice-free down to at least 65 feet. On the tundra itself, ice-rich permafrost was detected in the top 16 feet, but below that, the subsurface their imaging mapped was also ice-free."This leads to a new conceptual model," Pedrazas said.Permafrost is found in cold climates that remain frozen during the course of the year. Scientists have been tracking the impact of a warming climate on permafrost because as it melts, permafrost releases its stores of frozen carbon into the atmosphere as methane and carbon dioxide, contributing to climate change.Permafrost studies have almost exclusively focused on the region beneath the tundra. Because it's not easy to work in such remote locations and under harsh weather conditions, the transition from sea to shore has been largely ignored."This study tells us that the coastline is much more complicated than we thought," said co-author Jim McClelland from UT's Marine Science Institute. "It opens up the possibility for routes of water exchange that we weren't thinking about."Besides global considerations, the work has local impacts. The communities along the coast, most of whom are Inupiat, live on the permafrost. As the permafrost thaws, it accelerates coastal erosion, which carves away at the land on which homes and infrastructure stand. In the Kaktovik region, erosion can be as great as 13 feet per year."Their cultural heritage and their welfare is integrated and intricately linked to their environment," Cardenas said. "There's an immediate need to understand what's happening in these lagoons."The new paradigm requires reimagining the coastal Arctic ecosystem as well. Liquid groundwater means that carbon and nutrients can move between the tundra and the lagoon. It also means that saltwater can move beneath the tundra, potentially affecting freshwater sources.Paul Overduin, who wasn't involved in the research, but who studies permafrost at Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, said that this work is the first step in understanding permafrost's transition from sea to shore."As is often the case, when we start looking at something people don't know much about, you open up a whole bunch of questions that needed to be looked at," he said. "That's what's really exciting here."
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Climate
| 2,020 |
October 22, 2020
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https://www.sciencedaily.com/releases/2020/10/201022123118.htm
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Soil fungi act like a support network for trees
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Being highly connected to a strong social network has its benefits. Now a new University of Alberta study is showing the same goes for trees, thanks to their underground neighbours.
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The study, published in the Though past research has focused on seedlings, these findings give new insight into the value of fungal networks to older trees -- which are more environmentally beneficial for functions like capturing carbon and stabilizing soil erosion."Large trees make up the bulk of the forest, so they drive what the forest is doing," said researcher Joseph Birch, who led the study for his PhD thesis in the Faculty of Agricultural, Life & Environmental Sciences.When they colonize the roots of a tree, fungal networks act as a sort of highway, allowing water, nutrients and even the compounds that send defence signals against insect attacks to flow back and forth among the trees.The network also helps nutrients flow to resource-limited trees "like family units that support one another in times of stress," Birch noted.Cores taken from 350 Douglas firs in British Columbia showed that annual tree ring growth was related to the extent of fungal connections a tree had with other trees. "They had much higher growth than trees that had only a few connections."The research also showed that trees with more connections to many unique fungi had much greater growth than those with only one or two connections."We found that the more connected an adult tree is, the more it has significant growth advantages, which means the network could really influence large-scale important interactions in the forest, like carbon storage. If you have this network that is helping trees grow faster, that helps sequester more carbon year after year."It's also possible that if the trees grow faster, they'd have some ability to better survive drought that is expected to intensify with climate change, he added."These networks may help them grow more steadily even as conditions become more stressful, and could even help buffer trees against death."Birch hopes his findings lead to further studies in different kinds of forests in other geographical areas, because it's likely that the connections among trees change from year to year, he said."It's a very dynamic system that is probably being broken apart and re-formed quite a bit, like family relationships, so we don't know how they will change under future climates either. Maybe a dry year or a beetle outbreak impacts the network."Knowing whether fungal networks are operating the same way in other tree species could factor into how we reforest areas after harvesting them, and it could inform how we want to plant trees to preserve these networks."The research was supported by the Natural Sciences and Engineering Research Council of Canada.
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Climate
| 2,020 |
October 22, 2020
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https://www.sciencedaily.com/releases/2020/10/201022083313.htm
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Ice loss likely to continue in Antarctica, even if climate change is brought under control, study finds
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A new international study led by Monash University climate scientists has revealed that ice loss in Antarctica persisted for many centuries after it was initiated and is expected to continue.
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"Our study implies that ice loss unfolding in Antarctica today is likely to continue unbated for a long time -- even if climate change is brought under control," said lead study authors Dr Richard Jones and Dr Ross Whitmore, from the Monash University School of Earth, Atmosphere and Environment.The study, published today in The data records at least 220 meters of abrupt ice thinning between 7,500 and 4,500 years ago, followed by more gradual thinning until the last millennium.The study presents new results of ice sheet thinning in the southwestern Ross Sea. The results show that abrupt ice loss of several hundred meters occurred at a similar rate and duration across multiple outlet glaciers in the Mid-Holocene, despite complex bed topography.Both outlet glaciers demonstrate that abrupt deglaciation occurred across a broad region in the Mid-Holocene.When compared to regional sea-level and ocean-temperature changes, the study data indicate that ocean warming most likely drove grounding-line retreat and ice drawdown, which then accelerated as a result of marine ice sheet instability."We show that part of the Antarctic Ice Sheet experienced rapid ice loss in the recent geological past," said Professor Andrew Mackintosh, who heads the Monash School of Earth, Atmosphere and Environment."This ice loss occurred at a rate similar to that being observed in rapidly changing parts of Antarctica today, and it was caused by the same processes that are considered to cause current and probable future Antarctic ice mass loss -- ocean warming, amplified by internal feedbacks," he said."The retreat persisted for many centuries after it was initiated, which implies that ice loss unfolding in Antarctica today is likely to continue unabated for a long period."
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Climate
| 2,020 |
October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201021163936.htm
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Genome sequencing shows climate barrier to spread of Africanized bees
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Since the 1950s, "Africanized" honeybees have spread north and south across the Americas until apparently coming to a halt in California and northern Argentina. Now genome sequencing of hundreds of bees from the northern and southern limits shows a gradual decline in African ancestry across hundreds of miles, rather than an abrupt shift.
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"There's a gradual transition at the same latitude in North and South America," said Erin Calfee, graduate student in the Department of Evolution and Ecology at the University of California, Davis, and first author on the paper, published Oct. 19 in PLOS Genetics. "There's a natural barrier that is likely maintained by many different genetic loci."That barrier is mostly likely climate. Bees with majority African ancestry are unable to survive colder winters.European colonists brought European species of honeybees (Apis mellifera) with them to the Americas as early as the 1600s. In addition to apiaries, these bees established in the wild alongside native bees.In 1957, imported African honeybees of the subspecies Apis mellifera scutellata swarmed out of experimental hives in Brazil and started to rapidly spread, interbreeding with the resident European bees. Native to southern and eastern Africa, scutellata bees are known for their defensive behavior. They also carry some useful traits for beekeepers, such as resistance to Varroa mites.Calfee, working with Professor Graham Coop and Associate Professor Santiago Ramirez from the Department of Evolution and Ecology and collaborators in Argentina, sequenced the genomes of bees collected at the northern and southern edges of the scutellata expansion.They found that the bees at the northern and southern edges of the range have a highly variable mix of scutellata and European bee ancestry. The higher the latitude, the less scutellata ancestry is in the mix."The whole genome is tracking latitude and climate," Calfee said. There are likely many genes involved in climate sensitivity and winter survival, she said. But Calfee also finds that in some parts of the genome scutellata ancestry has spread far beyond these climate limits in both North and South America, evidence that some scutellata genes are advantageous and not tied to climate sensitivity. In contrast, the researchers did not find any evidence for selection for European ancestry in the spread of scutellata bees.The findings challenge the idea of a binary difference between "Africanized" and "European" honeybees, Ramirez said. In fact, all of these introduced honeybees are hybrids to some degree.The results of the study could be of interest for breeding bees for desirable traits, such as resistance to pathogens. Although the researchers looked only at gene sequences and not the resulting phenotypes (except for one, wing length), the results do show which genetic loci are important because they are under selection in the hybrid zones.Scutellata bees and hybrids have a lot more genetic diversity than European bees, and the researchers found that they lost very little of this diversity in their expansion from Brazil to California."Beekeepers can potentially draw from this genetic variation to breed for desirable traits," Ramirez said. What started out as an invasion may become part of the solution to declining bee health."It makes sense but it's kind of surprising because we have 1.5 million (honeybee) colonies being brought into California every spring to pollinate crops," Ramirez said. Those domesticated bees are then trucked around the country, but they do not appear to have a large effect on the spread of African ancestry into feral honeybee populations.
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Climate
| 2,020 |
October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201021140919.htm
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Turbulent era sparked leap in human behavior, adaptability 320,000 years ago
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For hundreds of thousands of years, early humans in the East African Rift Valley could expect certain things of their environment. Freshwater lakes in the region ensured a reliable source of water, and large grazing herbivores roamed the grasslands. Then, around 400,000 years ago, things changed. The environment became less predictable, and human ancestors faced new sources of instability and uncertainty that challenged their previous long-standing way of life.
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The first analysis of a new sedimentary drill core representing 1 million years of environmental history in the East African Rift Valley shows that at the same time early humans were abandoning old tools in favor of more sophisticated technology and broadening their trade networks, their landscape was experiencing frequent fluctuations in vegetation and water supply that made resources less reliably available. The findings suggest that instability in their surrounding climate, land and ecosystem was a key driver in the development of new traits and behaviors underpinning human adaptability.In the Oct. 21 issue of the journal Potts and colleagues documented this behavioral and cultural shift in 2018 based on artifacts recovered at an archaeological site known as Olorgesailie. Decades of study at Olorgesailie by Potts' team and collaborators at the National Museums of Kenya have determined that early humans at Olorgesailie relied on the same tools, stone handaxes, for 700,000 years. Their way of life during this period was remarkably stable, with no major changes in their behaviors and strategies for survival. Then, beginning around 320,000 years ago, people living there entered the Middle Stone Age, crafting smaller, more sophisticated weapons, including projectiles. At the same time, they began to trade resources with distant groups and to use coloring materials, suggesting symbolic communication. All these changes were a significant departure from their previous lifestyle, likely helping early humans cope with their newly variable landscape, Potts said."The history of human evolution has been one of increasing adaptability," Potts said. "We come from a family tree that's diverse, but all of those other ways of being human are now extinct. There's only one of us left, and we may well be the most adaptable species that may have ever existed on the face of the Earth."While some scientists have proposed that climate fluctuations alone may have driven humans to evolve this remarkable quality of adaptability, the new study indicates the picture is more complicated than that. Instead, the team's analysis shows that climate variability is but one of several intertwined environmental factors that drove the cultural shift they described in 2018. The new analysis reveals how a changing climate along with new land faults introduced by tectonic activity and ecological disruptions in the vegetation and fauna all came together to drive disruptions that made technological innovation, trading resources and symbolic communication¬ -- three key factors in adaptability -- beneficial for early humans in this region.In seeking to understand the major evolutionary transition they had uncovered at Olorgesailie, Potts and his team had been frustrated by a large gap in the region's environmental record. Erosion at Olorgesailie, a hilly area full of sedimentary outcrops, had removed the geologic layers representing some 180,000 years of time at exactly the period of this evolutionary transition. To learn about how the region changed during that period, they had to look elsewhere.They arranged to have a Nairobi company drill in the nearby Koora basin, extracting sediment from as deep into the earth as they could. The drill site, about 15 miles from the archaeological dig sites, was a flat, grassy plain, and the team had no clear idea what was beneath its surface. With the involvement and support from the National Museums of Kenya and the local Oldonyo Nyokie community, a 139-meter core was removed from the earth. That cylinder of earth, just four centimeters in diameter, turned out to represent 1 million years of environmental history.Colleagues in the National Museum of Natural History's Human Origins Program and Department of Paleobiology and dozens of collaborators at institutions worldwide worked to analyze the environmental record they had obtained, which is now the most precisely dated African environmental record of the past 1 million years. Charting radioisotope ages and changes in chemical composition and deposits left by plants and microscopic organisms through the different layers of the core, the team reconstructed key features of the ancient landscape and climate across time.They found that after a long period of stability, the environment in this part of Africa became more variable around 400,000 years ago, when tectonic activity fragmented the landscape. By integrating information from the drill core with knowledge gleaned from fossils and archeological artifacts, they determined that the entire ecosystem evolved in response.The team's analysis suggests that as parts of the grassy plains in the region were fragmented along fault lines due to tectonic activity, small basins formed. These areas were more sensitive to changes in rainfall than the larger lake basins that had been there before. Elevated terrain also allowed water runoff from high ground to contribute to the formation and drying out of lakes. These changes occurred during a period when precipitation had become more variable, leading to frequent and dramatic fluctuations in water supply.With the fluctuations, a broader set of ecological changes also took place. The team found that vegetation in the region also changed repeatedly, shifting between grassy plains and wooded areas. Meanwhile, large grazing herbivores, which no longer had large tracts of grass to feed on, began to die out and were replaced by smaller mammals with more diverse diets."There was a massive change in the animal fauna during the time period when we see early human behavior changing," Potts said. "The animals also influenced the landscape through the kinds of plants that they ate. Then with humans in the mix, and some of their innovations like projectile weapons, they also may have affected the fauna. It's a whole ecosystem changing, with humans as part of it."Finally, Potts notes that while adaptability is a hallmark of human evolution, that does not mean the species is necessarily equipped to endure the unprecedented change Earth is now experiencing due to man-made climate change and Anthropogenic biodiversity loss. "We have an astonishing capacity to adapt, biologically in our genes as well as culturally and socially," he said. "The question is, are we now creating through our own activities new sources of environmental disruption that will continue to challenge human adaptability?"Funding for this research was provided by the William H. Donner Foundation and the Peter Buck Fund for the National Museum of Natural History's Human Origins Program.
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Climate
| 2,020 |
October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201021130132.htm
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Protected areas help waterbirds adapt to climate change
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Climate change pushes species distribution areas northward. However, the expansion of species ranges is not self-evident due to e.g. habitat degradation and unsustainable harvesting caused by human activities. A new study led from the University of Turku, Finland, suggests that protected areas can facilitate wintering waterbird adaptation to climate warming by advancing their range shifts towards north.
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Researchers of the new study investigated the role of protected areas for the range shifts of wintering waterbirds in Europe and North Africa. Species communities were noted to shift faster inside protected areas compared to other areas.- Range shifts of waterbirds have been over 40 percent faster inside protected areas compared to outside areas. On average, species communities have shifted inside protected areas c. 90 kilometres in 25 years, says Postdoctoral Researcher Elie Gaget from the University of Turku.Protected areas not only increased the colonisation towards northern areas, but also prevented local extinctions on the southern range of species compared to non-protected areas. This suggests that protected areas can contribute to expand the overall range of species.In addition to single protected areas, the protected area network as a whole influenced the spread of waterbird species. Shifts in species communities were faster in areas with a dense protected area network compared to areas where the network was sparse.- Our findings highlight that protected area networks, historically established to fight habitat degradation and over-exploitation of natural resources, are now also important to mitigate the negative effects of climate warming on biodiversity, says Professor Jon Brommer from the University of Turku.The study is part of an international collaboration that utilised tens of thousands of waterbird surveys covering 97 species from 39 countries during 25 years. The international coordination of surveys has been conducted by Wetlands International and the research was published in the scientific journal of
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Climate
| 2,020 |
October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201021112333.htm
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Management of exploited transboundary fish stocks requires international cooperation
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Marine fish species are migratory in nature and not respectful of human-made territorial boundaries, which represents a challenge for fisheries management as policies tend to focus at the national level. With an average catch of 48 million tonnes per year, and USD $77 billion in annual fishing revenue, these species support critical fisheries, and require international cooperation to manage, according to UBC research.
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The researchers focused on fish species that cross the Exclusive Economic Zones (EEZs) of two or more coastal states which are most often targeted by fisheries operating within those EEZs. They identified over 633 exploited transboundary species worldwide and found that the catch and revenue from these fisheries had been severely underestimated and over-exploited."We found that some countries get over 80 per cent of their catch from transboundary species. These are not small numbers or small nations: these catches are specifically important in terms of revenue for Northern America and Eastern Asia," said Juliano Palacios Abrantes, a doctoral student in UBC's Institute for the Oceans and Fisheries, and lead author on the study. "Fishing nations such as China, the USA, Russia, Peru, and Japan alone are responsible for 41 per cent of the yearly global fisheries revenue from transboundary species.""Fisheries that include transboundary fish species, such as anchoveta in Peru's transboundary area with Chile or pollock in the U.S., Russia and Japan transboundary Alaskan region, catch on average 48 million tonnes per year, or USD $77 billion in annual fishing revenue," said William Cheung, senior author and professor in in UBC's Institute for the Oceans and Fisheries. "The catch from these fish species are declining at a much higher rate than non-transboundary species."There are agreements between countries in many of these EEZs. Peru and Chile recently signed an agreement towards standardizing stock assessments and management of the southern anchoveta stock. However, transboundary fisheries have led to some notorious fisheries-related conflicts, including those between those Canada, the USA, Russia, and the European Union. The EU, Norway, Iceland, and Denmark's Faroe Islands continue to be at odds over the allowable catch sizes for Atlantic mackerel, a transboundary fish species that has changed its distribution patterns due to climate change."Climate change is going to continue changing the distribution of fish stocks among countries, with some new transboundary species emerging and some disappearing," said Palacios Abrantes. "This can only lead to more difficulties if nations are not able to adapt and manage fisheries through effective international cooperation.""Collaborations are going to be needed to maximize long-term ecological, social, and economic benefits of shared marine species, particularly as stocks decline due to overfishing, and as fish populations move about the ocean in different patterns due to climate change," said Cheung. "Nations will have to adapt to these anthropogenic changes in our world as quickly, if not quicker, than fish species are having to do."
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Climate
| 2,020 |
October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201021112324.htm
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New sediment archive for historical climate research
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How has the climate changed in the course of the earth's history? Which climatic processes have influenced the earth and its atmosphere? Paleoclimatology seeks answers to such questions in order to better understand climate changes and to derive forecasts for future climate scenarios. So-called sedimentary archives serve as a basis for this. They are rock deposits whose components and composition provide information about the temperatures and climatic conditions at the time of their formation. Correspondingly recent geological deposits provide information about the climate development in the recent history of the earth since the last ice age 20,000 years ago. Compared to widespread seawater deposits, however, sedimentary archives on the mainland -- such as in the Alpine region -- are very rare.
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An international consortium led by the Institute of Applied Geosciences (IAG) of Graz University of Technology has now made a sensational discovery in this area. In a publication for Specifically, these are sedimentary fillings of faults and fractures which consist of the carbonate minerals dolomite, aragonite and calcite. It is known that the carbonate mineral dolomite crystallizes when seawater evaporates, which in turn requires high temperatures. Baldermann and his team have now been able to show for the first time that the mineral can also form at temperatures between zero and twenty degrees Celsius -- there has been no absolute data on this so far.In addition, the researchers discovered that these are comparatively geologically young minerals that were formed shortly after the last ice age about 20,000 years ago in a non-marine (continental) depositional area. Baldermann: "This is a novelty, as recent formations of the mineral have been restricted almost exclusively to seawater deposits until now."The entire range of geological investigation methods was used in the analyses. The rock samples were microscopically described and systematically classified. The mineralogical composition was determined by X-ray diffraction and the chemical properties were defined using high-resolution electron microscopy. For age dating and temperature reconstructions, the samples were analysed elementally and isotopically using state-of-the-art mass spectrometry. "The large number of results allowed us to draw conclusions about water flow, water composition, mineral growth and formation temperatures," says Baldermann."Climate research works mainly by analysing marine sediments, because we have archived a large number of sediments (marine sediments, note) over the entire course of the earth's history. Continental sedimentary archives are rare and are only very rarely considered. Their deposits usually provide only little information about old environmental conditions," says Baldermann. He is convinced that the newly published data on the deposits on the Erzberg will remedy this situation and provide new perspectives on climate development of the recent past.This research area is anchored in the Field of Expertise "Advanced Materials Science," one of the five strategic foci of TU Graz.The work was supported by NAWI Graz Central Lab Water, Minerals and Rocks, by the mining company VA Erzberg and by researchers from the Universities of Vienna and Graz. Financial resources were made available from the European Regional Development Fund (ERDF).
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Climate
| 2,020 |
October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201021085102.htm
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The effects of wildfires and spruce beetle outbreaks on forest temperatures
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Results from a study published in the
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The study examined temperatures within forests in a region of Colorado that has experienced wildfires and spruce beetle outbreaks within the last 10 to 15 years. Researchers used a network of sensors to record temperatures for a full year in burned and beetle-impacted areas.Burned areas were warmer than unburned forest. Conversely, canopy loss (the upper layer of trees) in unburned, beetle-killed forests resulted in slight cooling. This difference may be attributed to differing effects of each disturbance type on understory cover and residual canopy."We tend to assume that disturbances are going to catalyze climate change-driven forest declines, but we found that the type and severity of the disturbance matters," said lead author Amanda Carlson, PhD, of Colorado State University. "Elevated temperatures in burned forests could indicate that trees will have a more difficult time re-establishing, but the fact that we did not observe amplified warming in beetle-killed stands could indicate that forests will be much more resilient to that type of disturbance."
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October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201007123127.htm
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Phosphorus deficit may disrupt regional food supply chains
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Phosphorus is essential in agriculture to maintain higher production levels, where it is applied as a fertilizer. Some of the world regions are experiencing high population growth rates, which means more phosphorus will be needed to produce an increasing amount of food needed in the next decades. A new study -- Global phosphorus supply chain dynamics: Assessing regional impact to 2050 -- published in the scientific journal
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Almost all of our phosphate fertilizers come from the mining and processing of phosphate rock (PR) and only a handful of countries produce and export this mineral. Losses along the Phosphorus (P) supply chain have been estimated in the literature at around 80-90% . At the same time, global population growth is expected to push food demand up by more than 50% to 2050, particularly in Latin America and Caribbean (LAC), South Asia (SA) and Sub-Saharan Africa (SSA) . Despite being a vital resource in food production, P is also a key pollutant in water bodies, where it can cause eutrophication. Processing PR is also an energy-intensive process, which uses significant quantities of water and produces large quantities of phosphogypsum (PG), a toxic and radioactive byproduct."Most of the focus in the literature has been on the sufficiency of the global phosphorus reserves. However, demand for phosphorus is unequal across regions so it was important to assess which regions require more phosphorus and what will that mean in terms of food security. Another valuable contribution of this study is that we quantified the negative environmental and climate impacts of the phosphorus supply chain at global and regional level. Our results indicate yet again the necessity of closing the loop when it comes to phosphorus and on reducing its usage through more sustainable farming practices" says Claudiu Eduard Nedelciu, researcher at the Department of Physical Geography and main author of the study.The study, which is part of a larger European research project, Adaptation to a new Economic Reality, found that LAC, SA and ESEA will lead the increasing consumption of P in the coming decades. Surprisingly, SSA did not account for a significant increase in the P requirement to 2050, despite developing the highest population growth during the period. This is due to the historically low levels of fertilizer application in the region, but poses serious questions about food security, as this part of the world concentrates most of the undernourished people in the world. All the regions leading the increase in P requirement were also regions highly dependent on phosphate imports and thus vulnerable to price spikes and supply disruptions."Hunger will increase in the parts of the world where phosphorus is lacking, unless actions are taken by governments and international institutions to secure imports," aid Prof. Kristin Vala Ragnasdottir from the University of Iceland, co-author in the study.Perhaps the most striking results were related to the impact of the P supply chain on the environment and climate. The amount of P reaching water bodies will more than triple in North Africa and Western Asia and will double in South Asia and Latin America and the Caribbean. This trend will be driven by P runoff from agricultural land and it is an optimistic scenario, as it assumes that the 2030 wastewater treatment targets of the Sustainable Development Goals (SDGs) will be achieved in all world regions. At current P runoff rates and without ambitious prevention measures, more coastal areas and inland water bodies are likely to be subject to eutrophication."Not only the efficient use of Phosphorus in agriculture but wise management of Phosphorus resources along the supply chain, including environmental effects, will be major challenges for the coming decades" said Prof. Peter Schlyter of the Blekinge Technology Institute and co-author in the study.Climate impact resulting from the mining and processing of PR will double in 2050 compared to 2000, while the amount of phosphogypsum production will reach 500 million tons/year if no technological improvements are made. Production of phosphogypsum raises serious questions with regard to its safe disposal and management, owing to its toxicity and radioactivity. On the other hand, phosphogyspum can be a rich source for P in the future, if technological advancements will allow the safe recycling of phosphorus.
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October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201021085119.htm
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What cold lizards in Miami can tell us about climate change resilience
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It was raining iguanas on a sunny morning.
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Biologist James Stroud's phone started buzzing early on Jan. 22. A friend who was bicycling to work past the white sands and palm tree edges of Key Biscayne, an island town south of Miami, sent Stroud a picture of a 2-foot long lizard splayed out on its back. With its feet in the air, the iguana took up most of the sidewalk.The previous night was south Florida's coldest in 10 years, at just under 40 degrees Fahrenheit. While most people reached for an extra blanket or a pair of socks, Stroud -- a postdoctoral research associate in Arts & Sciences at Washington University in St. Louis -- frantically texted a collaborator:"Today's the day to drop everything, go catch some lizards."When temperatures go below a critical limit, sleeping lizards lose their grip and fall out of trees. From previous research, Stroud and his colleagues had learned that different types of lizards in Miami can tolerate different low temperatures, ranging from about 46 to 52 degrees Fahrenheit, before they are stunned by cold. This cold snap provided a unique opportunity to understand how they are affected by extreme climate events.But when the researchers collected the scaled survivors of that coldest night, they discovered that the lizard community responded in an unexpected way: all of them could tolerate cold temperatures down to about 42 degrees Fahrenheit, regardless of their species' previous ability to withstand cold. The findings are reported Oct. 21 in the journal "Prior to this, and for a different study, we had measured the lowest temperatures that six lizard species in south Florida could tolerate," Stroud said. "We realized after the 2020 cold event that these data were now extremely valuable -- we had the opportunity to re-measure the same lizard populations to observe if their physiological limits had changed; in other words, could these species now tolerate lower temperatures?"In the days that followed the January cold snap, researchers collected representatives of as many different kinds of lizards as they could find in the local area, rounding up small and large lizards and those that are active during the day and at night. Then the researchers tested their response to cold."A major unexpected result of this study was that all species converged on the same new, lower level of thermal tolerance," Stroud said. "While there was great variation in temperature tolerance before the cold event -- some, like the large-bodied brown basilisk, were very intolerant of low temperatures, while others like the Puerto Rican crested anole were more robust -- we observed that all species could now tolerate, on average, the same lowest temperature."Given great variation in body size, ecology and physiology, this was unexpected," he said.Only one of the species in the study is native to the area; the rest have been introduced to Florida over the past century, researchers noted.The results provide evidence that tropical, cold-blooded creatures -- often characterized as unable to withstand rapid changes in climatic conditions -- can sometimes endure conditions that exceed their established physiological limits."The shifts to tolerate significantly lower temperatures that we observed were so large that we found it unclear whether natural selection was responsible," Stroud said. "And so in our paper we discuss other alternative processes which may also have led to this pattern.""The results of this study are surprising and unexpected. Who would have thought that tropical lizards from places like Puerto Rico and Central America could withstand temperatures near freezing?" said Jonathan Losos, the William H. Danforth Distinguished University Professor and professor of biology in Arts & Sciences and director of the Living Earth Collaborative at Washington University."What we now need to find out is how this was accomplished. Is this evidence of natural selection, with those lizards that just happened to have a lower cold tolerance surviving and others freezing to death, or was it an example of physiological adjustment -- termed 'acclimation' -- in which exposure to lower temperatures changes a lizard's physiology so that it is capable of withstanding lower temperatures?"Regardless of the underlying mechanism, the new study provides a critically important piece of information for understanding the impacts of climate change.Scientists expect that air temperatures will gradually become warmer under climate change, but also that temperatures will become more chaotic.Events that spike temperature to extremes -- both exceptionally hot and exceptionally cold episodes -- will increase in frequency and magnitude. As such, it is important to understand both the effects of gradual, long-term increases in air temperatures as well as the consequences of abrupt, short-term extreme events."It is widely thought that tropical and subtropical species are going to be especially vulnerable to changes in temperature -- particularly extreme spikes of heat or cold -- as tropical areas do not typically have strong seasons," Stroud said. "Unlike temperate species, which are adapted to summer highs and winter lows, tropical species have typically evolved in very thermally stable environments."While there is no doubt that climate change represents a major threat to species and ecosystems around the world, and deserves as much research attention as possible, this study provides fascinating insight and a glimpse of hope," he said. "Perhaps tropical and subtropical species can withstand more extreme climatic conditions."
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October 20, 2020
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https://www.sciencedaily.com/releases/2020/10/201020135644.htm
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A new material for separating CO2 from industrial waste gases, natural gas, or biogas
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Chemists at the University of Bayreuth have developed a material that could well make an important contribution to climate protection and sustainable industrial production. With this material, the greenhouse gas carbon dioxide (CO
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The "Green Deal," presented by the European Commission in 2019, calls for the net emissions of greenhouse gases within the EU to be reduced to zero by 2050. This requires innovative processes that can separate and retain CO"Our research team has succeeded in designing a material that fulfils two tasks at the same time. On the one hand, the physical interactions with COThe new material is an inorganic-organic hybrid. The chemical basis is clay minerals consisting of hundreds of individual glass platelets. These are only one nanometre thick each, and arranged precisely one above the other. Between the individual glass plates there are organic molecules that act as spacers. Their shape and chemical properties have been selected so that the pore spaces created are optimally tailored to accumulate COThe development of a hybrid material tailor-made for the separation and supply of CO
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Climate
| 2,020 |
October 20, 2020
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https://www.sciencedaily.com/releases/2020/10/201020131353.htm
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Microbial diversity below seafloor is as rich as on Earth's surface
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For the first time, researchers have mapped the biological diversity of marine sediment, one of Earth's largest global biomes. Although marine sediment covers 70% of the Earth's surface, little was known about its global patterns of microbial diversity.
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A team of researchers from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the University of Hyogo, the University of Kochi, the University of Bremen, and the University of Rhode Island delineated the global diversity of microbes in marine sediment. For the study, published in the The 16S rRNA gene sequences (approximately 50 million sequences) obtained through comprehensive next-generation sequencing were analyzed to determine microbial community composition in each sample. From these 50 million sequences, the research team discovered nearly 40,000 different types of microorganisms in marine sediment, with diversity generally decreasing with depth. The team found that microbial community composition differs significantly between organic-rich sediment of continental margins and nutrient-poor sediment of the open ocean, and that the presence or absence of oxygen and the concentration of organic matter are major factors in determining community composition.By comparing their results to previous studies of topsoil and seawater, the researchers discovered that each of these three global biomes -- marine sediment, topsoil, and seawater -- has different microbial communities but similar total diversity. "It was an unexpected discovery that microbial diversity in the dark, energy-limited world beneath the seafloor is as diverse as in Earth's surface biomes," said Hoshino.Furthermore, by combining the estimates of bacterial and archaeal diversity for these three biomes, the researchers found that bacteria are far more diverse than archaea -- microbes distinct from bacteria and known for living in extreme environments -- on Earth."In this respect as well, microbial diversity in the dark realm of marine sediment resembles microbial diversity in the surface world," said D'Hondt. "It's exciting to glimpse the biological richness of this dark world."
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Climate
| 2,020 |
October 20, 2020
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https://www.sciencedaily.com/releases/2020/10/201020105530.htm
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Depths of the Weddell Sea are warming five times faster than elsewhere
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Over the past three decades, the depths of the Antarctic Weddell Sea have warmed five times faster than the rest of the ocean at depths exceeding 2,000 metres. This was the main finding of an article just published by oceanographers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). In the article, they analyse an unprecedented oceanographic time series from the Weddell Sea and show that the warming of the polar depths is chiefly due to changed winds and currents above and in the Southern Ocean. In addition, the experts warn that the warming of the Weddell Sea could permanently weaken the overturning of tremendous water masses that takes place there -- with far-reaching consequences for global ocean circulation. Their study was just released on the online portal of the
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Over the past several decades, the world's oceans have absorbed more than 90 percent of the heat trapped in the atmosphere by greenhouse-gas emissions, effectively slowing the rise in air temperatures around the globe. In this regard, the Southern Ocean is pivotal. Though it only accounts for 15 percent of the world's oceans in terms of area, because of the overturning that takes place there, it absorbs roughly three-fourths of the heat.Until recently, very little was known about what happens to this heat in the depths of the Southern Ocean, due to the lack of sufficiently long time series. In order to trace the development down to the seafloor, researchers relied on regularly repeated ship-based measurements taken with 'CTD' probes (Conductivity, Temperature and Depth). These probes have now become so precise that they can measure changes in water temperature down to the nearest ten-thousandth of a degree Celsius. The data they gather can also be used to determine the water masses' density and salinity.For the past 30 years, AWI oceanographers have been taking these temperature and salinity readings during expeditions to the Weddell Sea on board the German research icebreaker Polarstern -- always at the same sites, always from the surface to the seafloor, and always with extremely high accuracy. By doing so, the researchers have produced the only time series of its kind on the South Atlantic and the Weddell Sea, which has now allowed them to precisely reconstruct the warming of the Weddell Sea and identify potential causes.Their findings are surprising. "Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we're seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year," says Dr Volker Strass, an AWI oceanographer and the study's first author.These values may seem minuscule at first glance. But, as Strass explains, "Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average." Through the formation of bottom water in the Weddell Sea, this heat is then distributed to the deep basins of the world's oceans.In the Weddell Sea, which represents the southern extension of the Atlantic Ocean and is roughly ten times the size of the North Sea, tremendous water masses cool down. In the course of sea-ice formation they take on salt, sink to deeper water layers as cold and heavy Antarctic Bottom Water, and then spread to the great ocean basins as a deep-sea current. This overturning is considered to be an important motor for the global ocean circulation. The warming of the depths of the Weddell Sea could weaken that motor, since warmer water has a lower density. Consequently, it is lighter and could fill higher layers of the water column."Our field data already shows a temperature-related loss in density in the deeper water masses of the Weddell Sea. This change is most pronounced in the Bottom Water," says co-author and AWI oceanographer Gerd Rohardt. Whether or not the Antarctic Bottom Water will continue to fulfil its function as the deepest limb of the global ocean overturning circulation chiefly depends on how the density of the water masses above it changes. "In order to monitor these developments, we'll need to continue our regular ship-based readings in the Weddell Sea," says the researcher.As the cause of the increased heat input in the depths of the Weddell Sea, the researchers have identified a change in the wind and current systems over and in the Southern Ocean. "Over the past three decades, the westerlies and with them the Antarctic Circumpolar Current have not only shifted one to two degrees to the south; they have also intensified. As a result, the diameter of the Weddell Gyre has decreased, and the flow speed of the water masses has increased. Because of these two factors, more heat from the Circumpolar Current is transported to the Weddell Sea today than when we first began our measurements," explains Prof Torsten Kanzow, Head of the AWI's Climate Sciences Division and another co-author of the study.Once the heat reaches the depths of the Weddell Sea, the major bottom water currents distribute it to all ocean basins. "Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world's oceans," says Volker Strass. If the warming of the Weddell Sea continues unchecked, he explains, it will have far-reaching consequences not only for the massive ice shelves on the southern coast of the Weddell Sea, which extend far out into the ocean, and as such, for sea-level rise in the long term, but also for the conveyor belt of ocean circulation as a whole.
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Climate
| 2,020 |
October 20, 2020
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https://www.sciencedaily.com/releases/2020/10/201020081737.htm
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Declines in shellfish species on rocky seashores match climate-driven changes
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The waters of the Gulf of Maine are warming faster than oceans almost anywhere on Earth. And as the level of carbon dioxide rises in the atmosphere, it's absorbed by the oceans, causing pH levels to fall. Ocean acidification makes it difficult for shellfish to thicken their shells -- their primary defense against predators.
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In a new study in the journal "These species are often overlooked because of how common they are," Petraitis says. "They're just everywhere across the rocky shores. People don't think anything is going to happen to them. If they decline by about 3% a year that's a relatively small change so you might not notice it for a while. But one year, people are going to suddenly look around and say, 'Where are all the snails, mussels and barnacles?'"These species "form the core of an iconic food web" in the Gulf of Maine, says Dudgeon. "Concurrent declines of five species, including both native and non-native, is proportionally large, and may cause profound changes in the ecology of coastal oceans in the region."In 1997, Petraitis and Dudgeon set up a long-term experiment on the Gulf of Maine's Swan's Island to study the ecological principles of multiple stable states. A focus of Petraitis's research and the subject of his 2013 book, "Multiple Stable States in Natural Ecosystems," the concept encapsulates the idea that an ecosystem can switch quickly between entirely different compositions of organisms, given the right environmental perturbations.For shellfish on Swan's Island, one such perturbation occurs when periodic powerful winter storms cause sea ice to scrape off all the organisms attached to rocks on the shore, forcing the communities to rebuild from scratch the next year.In 1996, Petraitis and Dudgeon simulated a single massive ice scouring event by scraping the rocks to see what would happen as the shore recolonized. Since then the researchers have been making an annual trip to their 60 study plots on Swan's Island, counting the incidence of organisms living not only in the scraped areas but also in areas left in their natural state, the control plots.The current work took advantage of these control plot counts, looking at five common shellfish species: the tortoiseshell limpet (Testudinalia testudinalis), the common periwinkle (Littorina littorea), the dogwhelk (Nucella lapillus), the blue mussel (Mytilus edulis), and the barnacle (Semibalanus balanoides)."We didn't expect to see much change in the control plots," says Petraitis, "but we were surprised to see these populations declining."Using abundance data from 1997 to 2018, the researchers found that very young mussels were in the sharpest free fall, declining almost 16% a year, while the other four species were dwindling by 3 to 5% each year. Over that time period, limpets, periwinkles, and dogwhelks declined in total number by 50%, contractions the researchers describe as "sobering."To get at the question of why, the researchers looked to data on ocean temperature and chemistry. They found that the downward trajectory of mussels and common periwinkles matched up with increasing summer ocean temperatures collected from a nearby buoy.Meanwhile declines in populations of limpets and dogwhelks corresponded with increases in the aragonite saturation state, a measurement that tracks with ocean pH. This was unexpected, since lower levels of aragonite saturation are associated with more acidic oceanwaters, which make it harder for shellfish to build up their shells. "This may be indicative of other conditions at nearshore areas that vary with aragonite saturation state," Petraitis says.Changes in barnacle numbers did not correspond with changes in ocean temperature, pH, or aragonite saturation state, suggesting other factors are at play in their decline.All five of these species play critical ecological roles in the Gulf of Maine.As filter feeders, mussels and barnacles remove phytoplankton from the water column, "digesting them, pooping them out, and fertilizing the shore," Petraitis says. Limpets and periwinkles feed on algae and seaweed, so smaller numbers could lead to algal blooms and "greener" nearshore areas.Since all five species serve as prey for a variety of animals, shrinking populations will reverberate up the food chain, affecting humans as well."Without animal consumption transferring organic matter up the food web," says Dudgeon, "production in coastal oceans will be increasingly shunted directly through pathways of decomposition by microbial organisms, rather than to support populations of species that humans fish and on which coastal economies depend."Petraitis also notes the common periwinkle, now emblematic of the coast, was introduced to the Gulf of Maine from Europe sometime in the middle of the 19th century. "Now it's the most common grazer on the shores -- they feed like goats," he says. "Before 1860, the shore without periwinkles probably looked a lot greener than it does now. As they decline we may see the shore revert back to its state in the 1850s."While presenting these findings at conferences in the last couple of years, Petraitis says he's heard anecdotes from other scientists about similar disappearances of mussels across the North Atlantic, suggesting the phenomenon is not isolated to the Gulf of Maine.The study was supported by the National Science Foundation (grants OCE-9529564, DEB-0314980, DEB-1020480, and DEB- 1555641).
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Climate
| 2,020 |
October 19, 2020
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https://www.sciencedaily.com/releases/2020/10/201019145549.htm
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Tiny beetles a bellwether of ecological disruption by climate change
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As species across the world adjust where they live in response to climate change, they will come into competition with other species that could hamper their ability to keep up with the pace of this change, according to new University of Colorado Boulder-led research.
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The new findings, published this month in the "The experiment shows how interspecies competition can put certain species at greater risk of extinction," said Geoffrey Legault, lead author of the study, who conducted the research while earning his doctoral degree in ecology and evolutionary biology at CU Boulder. "It has enabled us to improve the ecological models, and that helps us to make better predictions about nature."The researchers found that competition between species sets the boundary where species expand their ranges, providing support for including interspecies competition in ecological models and studies that monitor, forecast or manage these changes in the natural world.To achieve this new finding, the researchers used two species of a small, but resilient insect: the flour beetle.Flour beetles have been studied since the early 1900s and are a model organism in ecology. In the same way that fruit flies are used as a model organism for studying genetics, flour beetles can represent the fundamental ecology of most organisms and their responses in the lab can be applied to larger ecological trends and patterns in the natural world.In nature, these tiny creatures live on the ground in the leaf litter and in the bark of trees. While inconspicuous to us, they are common across the world.In the lab, the researchers lined up a series of 1.5 inch-long plexiglass boxes joined by holes, which they could open and close like fences. The two species of flour beetles were born into opposite ends of this lineup, then observed as their populations expanded across the landscape and competed with each other."It's a microcosm of the larger natural world that allows you to focus in on the core processes of birth, death and movement," said Brett Melbourne, senior author on the study and associate professor of ecology and evolutionary biology.Upon entering Melbourne's laboratory, you might think you are in a bakery -- not a space where scientific experiments are conducted. There is a dusting of flour everywhere and much of the equipment is more what you'd find in a bakery than a lab."We even sift the flour like you're supposed to when you're baking something," said Legault, currently a postdoctoral fellow at the University of British Columbia.Flour is both the flour beetles' habitat and their food source -- but it's also a high-demand human food product. The beetles are considered a major stored product pest, as they can get into not only your cupboards, but grain silos and flour mills. As a result, many studies about these insects focus on exterminating them.But for the researchers, these food pests are perfect for conducting tightly controlled experiments. As the beetles have a short life cycle, observing their populations across many generations can be done within a year.Yet the work is still intensive. In the year of the experiment, 24 CU Boulder undergraduates assisted Legault and Melbourne in counting more than a million beetles.For Melbourne, this research is especially critical in relationship to climate change."One way that species are experiencing climate change is that their habitat is moving: It's either going up mountain sides or it's moving toward the poles," said Melbourne.In many parts of the world, the pace at which habitats are moving in these northern and upward directions across the globe is more than a kilometer per year, according to Melbourne. That is really fast, especially for species with limited ability to change where they live.Predictions on how well a species will survive due to climate change moving their habitat often focus on single, individual species. But as many species migrate to new areas, they will encounter established species that already live there. Because the two species may rely on the same food sources or other resources, the survival of both is threatened."These kinds of species interactions could be super important for the long-term persistence or extinction of species in response to moving habitats," Melbourne said.Additional authors on this paper include Matthew Bitters in the Department of Ecology and Evolutionary Biology at CU Boulder; and Alan Hastings of the University of California and Santa Fe Institute.
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Climate
| 2,020 |
October 19, 2020
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https://www.sciencedaily.com/releases/2020/10/201019125512.htm
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Driver of the largest mass extinction in the history of the Earth identified
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Life on Earth has a long, but also an extremely turbulent history. On more than one occasion, the majority of all species became extinct and an already highly developed biodiversity shrank to a minimum again, changing the course of evolution each time. The most extensive mass extinction took place about 252 million years ago. It marked the end of the Permian Epoch and the beginning of the Triassic Epoch. About three quarters of all land life and about 95 percent of life in the ocean disappeared within a few thousands of years only.
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Gigantic volcanic activities in today's Siberia and the release of large amounts of methane from the sea floor have been long debated as potential triggers of the Permian-Triassic extinction. But the exact cause and the sequence of events that led to the mass extinction remained highly controversial. Now, scientists from Germany, Italy and Canada, in the framework of the EU-funded project BASE-LiNE Earth led by Prof. Dr. Anton Eisenhauer from GEOMAR Helmholtz Centre for Ocean Research Kiel in cooperation with the Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, have for the first time been able to conclusively reconstruct the entire cascade of events at that time using cutting-edge analytical techniques and innovative geochemical modelling. The study has been published today in the international journal For their study, the BASE-LiNE Earth team used a previously often neglected environmental archive: the shells of fossil brachiopods. "These are clam-like organisms that have existed on Earth for more than 500 million years. We were able to use well-preserved brachiopod fossils from the Southern Alps for our analyses. These shells were deposited at the bottom of the shallow shelf seas of the Tethys Ocean 252 million years ago and recorded the environmental conditions shortly before and at the beginning of extinction," explains Dr. Hana Jurikova. She is first author of the study, which she conducted as part of the BASE-LiNE Earth project and her doctoral thesis at GEOMAR.By measuring different isotopes of the element boron in the fossil shells, the team was able to trace the development of the pH values in the ocean 252 million years ago. Since seawater pH is tightly coupled to the CO"With this technique, we can not only reconstruct the evolution of the atmospheric COAs a next step, the team fed their data from the boron and additional carbon isotope-based investigations into a computer-based geochemical model that simulated the Earth's processes at that time. Results showed that warming and ocean acidification associated with the immense volcanic COOver thousands of years, increasing amounts of nutrients reached the oceans via rivers and coasts, which then became over-fertilized. The result was a large-scale oxygen depletion and the alteration of entire elemental cycles. "This domino-like collapse of the inter-connected life-sustaining cycles and processes ultimately led to the observed catastrophic extent of mass extinction at the Permian-Triassic boundary," summarizes Dr. Jurikova.The study was conducted within the framework of the EU-funded ITN project BASE-LiNE Earth, in which the use of brachiopods as an environmental archive was systematically studied for the first time, and relevant analytical methods were improved and newly developed. "Without these new techniques it would be difficult to reconstruct environmental processes more than 250 million years ago in the same level of detail as we have done now," emphasizes Prof. Dr. Anton Eisenhauer from GEOMAR, the former BASE-LiNE Earth project coordinator and co-author of the new study, "in addition, the new methods can be applied for other scientific applications."
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Climate
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October 19, 2020
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https://www.sciencedaily.com/releases/2020/10/201019112119.htm
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Paper recycling must be powered by renewables to save climate
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Recycling paper may only be helpful to the climate if it is powered by renewable energy, according to a new modelling study by researchers at UCL and Yale.
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The study, published in The researchers modelled various scenarios for increasing recycling of wastepaper by 2050 and the impact this would have on greenhouse emissions. They found that if all wastepaper was recycled, emissions could increase by 10%, as recycling paper tends to rely more on fossil fuels than making new paper.However, the researchers found that emissions would radically reduce if paper production and disposal were carried out using renewable energy sources rather than fossil fuels.Making new paper from trees requires more energy than paper recycling, but the energy for this process is generated from black liquor -- the low-carbon by-product of the wood pulping process. In contrast, paper recycling relies on fuels and electricity from the grid.Researchers found that modernising landfill practices, for instance by capturing methane emissions and using them for energy, also had a positive effect -- although not as profound as moving to renewables.Lead author Dr Stijn van Ewijk (UCL Institute for Sustainable Resources and Yale Center for Industrial Ecology) said: "Our study shows that recycling is not a guaranteed way to address climate change. Recycling of paper may not be helpful unless it is powered by renewable energy."We looked at global averages, but trends may vary considerably in different parts of the world. Our message isn't to stop recycling, but to point out the risk of investing in recycling at the expense of decarbonising the energy supply and seeing very little change to emissions as a result."Senior author Professor Paul Ekins (UCL Institute for Sustainable Resources) said: "The recycling of some materials, for instance metals, can lead to a very large reduction in emissions. But we need to be careful about assumptions that recycling, or a circular economy in general, will always have a positive effect on climate change."The researchers emphasized that recycling has benefits beyond combatting global warming. Co-author Professor Julia Stegemann (UCL Civil, Environmental & Geomatic Engineering) said: "Our exponentially increasing consumption of global resources has many seriously damaging environmental impacts beyond climate change, and conserving resources, including by paper recycling, remains critical for sustainability."The researchers reported that paper accounted for 1.3% of global greenhouse gas emissions in 2012. About a third of these emissions came from the disposal of paper in landfills. Researchers said that in coming years, use of paper would likely rise, with the move away from plastics leading to increased demand for paper packaging.The study looked at how different levels of recycling, renewable energy use and more environmentally friendly landfill practices might affect our ability to reduce emissions in line with a target to avoid a 2-degrees Celsius temperature rise by 2050.It found that if past trends continued, emissions would slightly increase from the 2012 level (721 metric tonnes of carbon dioxide equivalent in a year) to 736 metric tonnes in 2050, with efforts to reduce emissions outweighed by increased demand for paper.A radical programme of recycling, with landfill and energy uses remaining on the same path, would increase this still further by 10% (to 808 metric tonnes), with savings due to a decrease in total energy use outweighed by an increase in the use of high-carbon electricity.On the other hand, radically modernising landfill practices would reduce emissions to 591 metric tonnes, while moving to renewables, with recycling and landfill practices remaining on the standard path, would reduce emissions by 96% to 28 tonnes.Researchers explained that, while paper recycling can save trees and protect forest carbon stocks, the extent of this is unknown. This is because of a lack of understanding of the global forest carbon stock and the interrelated causes of deforestation. The analysis, therefore, assumes that recycling neither harms nor benefits forests.
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Climate
| 2,020 |
October 18, 2020
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https://www.sciencedaily.com/releases/2020/10/201018092801.htm
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Marine protected area urged for Antarctica Peninsula
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The Western Antarctic Peninsula is one of the fastest warming places on earth. It is also home to threatened humpback and minke whales, chinstrap, Adélie and gentoo penguin colonies, leopard seals, killer whales, seabirds like skuas and giant petrels, and krill -- the bedrock of the Antarctic food chain.
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With sea ice covering ever-smaller areas and melting more rapidly due to climate change, many species' habitats have decreased. The ecosystem's delicate balance is consequently tilted, leaving species in danger of extinction.Cumulative threats from a range of human activities including commercial fishing, research activities and tourism combined with climate change is exacerbating this imbalance, and a tipping point is fast approaching.Dr Carolyn Hogg, from the University of Sydney School of Life and Environmental Sciences, was part of the largest ever all-female expedition to the Antarctic Peninsula, with the women in STEMM initiative, Homeward Bound, in late 2019. There, she witnessed the beauty and fragility of the area, and the negative impacts of climate change and human activity on native species, first-hand. As part of the Homeward Bound program she learnt about the science, conservation and governance of Antarctica.In a new commentary piece published in A global initiative, Homeward Bound 'aims to elevate the voices of women in science, technology, engineering mathematics and medicine in leading for positive outcomes for our planet'.Women are noticeably absent in Antarctica's human history, which is steeped in tales of male heroism. Female scientists are still a minority in the region's research stations."Now, more than ever, a broad range of perspectives is essential in global decision-making, if we are to mitigate the many threats our planet faces," said Dr Hogg."Solutions include the ratification of a Marine Protected Area around the Peninsula, set to be discussed on 19 October, at a meeting of a group of governments that collectively manage the Southern Ocean's resources," said Dr Hogg. "The region is impacted by a number of threats, each potentially problematic in their own right, but cumulated together they will be catastrophic."The Peninsula's waters are home to 70 percent of Antarctic krill. In addition to climate change, these krill populations are threatened by commercial fishing. Last year marked the third largest krill catch on record. Nearly 400,000 tonnes of this animal were harvested, to be used for omega-3 dietary supplements and fishmeal."Even relatively small krill catches can be harmful if they occur in a particular region, at a sensitive time for the species that live there," said Dr Cassandra Brooks, a co-author on the comment from the University of Colorado, Boulder. "For example, fishing when penguins are breeding lowers their food intake, and affects their subsequent breeding success. A Marine Protected Area will conserve and protect this unique ecosystem and its wildlife, and we need to implement it now."Climate change is fundamentally altering the Western Antarctic Peninsula:As sea ice recedes, populations of larval and juvenile krill, which use the ice for shelter and to feed off the algae it attracts, decline.A warmer climate and less sea-ice cover will also give opportunities to invasive species, which can enter the territory via international ships, including those carrying tourists.Tourism's footprint is growing. The Peninsula is the most-visited region in Antarctica, owing to its proximity to South America, dramatic beauty and rich marine ecosystem.Tourist numbers have more than doubled in the past decade, with 74,000 visiting last year compared to 33,000 in 2009."Ships can pollute the ocean with micro-plastics, oils and ship noise," said Dr Justine Shaw, another co-author from the University of Queensland.While the International Association of Antarctica Tour Operators (IAATO), a self-regulating association that advocates for safe and environmentally responsible travel, provides guidelines for cruise ships and tourists, "an increasing number of vessels that are not IAATO members and that carry up to about 500 passengers have begun visiting the region, and this is concerning as it adds greater pressure," Dr Shaw said.While the collection of data and knowledge is important, research activities can also potentially damage the Antarctic Peninsula's sensitive environment, the team stated.The Peninsula hosts science facilities belonging to 18 nations -- the highest concentration on the continent. New stations and expansions are ever-present.While these scientific endeavours can increase our understanding of native species', there can be negative impacts on the region if not properly managed. Dr Shaw explained: "Buildings and infrastructure displace wildlife and vegetation."The authors endorse a proposed MPA for the western Antarctic Peninsula. Led by Chile and Argentina, this is due to be discussed during a two-week meeting commencing 19 October by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), a group of governments that collectively manage the Southern Ocean's resources.The MPA would reduce commercial fishing in ecologically sensitive areas, helping preserve the food chain and ensuring greater sustainability for the future in surrounding areas.A comparable MPA for the Ross Sea, in southern Antarctica, was agreed to in October 2016 to global celebration.Only 1.5 percent of Antarctica's ice-free terrain enjoys formal protected status. Much unprotected land is adjacent to research and tourist areas and is therefore vulnerable to human-generated risks like pollution and invasive species.The authors call for a greater extent and variety of landscapes to be protected."Globally, parties to the Convention on Biological Diversity have agreed that 17 percent of land should be protected to ensure conservation of biodiversity. This is a good starting point for Antarctica," Dr Hogg said.For conservation efforts to be effective, they have to be collaborative. Dr Shaw furnished examples: "The Council of Managers of National Antarctic Programs (COMNAP) must work to limit the expansion of research infrastructure. Tour operators' body IAATO and parties to the Antarctic Treaty System should cooperate to better manage tourist activity -- ensuring all tour operators abide by IAATO regulations regardless of whether they are IAATO members."
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016164230.htm
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Deep sea coral time machines reveal ancient CO2 burps
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The fossilised remains of ancient deep-sea corals may act as time machines providing new insights into the effect the ocean has on rising CO
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Rising COThe team collected fossil remains of deep-sea corals that lived thousands of metres beneath the waves. By studying the radioactive decay of the tiny amounts of uranium found in these skeletons, they identified corals that grew at the end of the ice age around 15,000 years ago.Further geochemical fingerprinting of these specimens -- including measurements of radiocarbon -- allowed the team to reconstruct changes in ocean circulation and compare them to changes in global climate at an unprecedented time resolution.Professor Laura Robinson, Professor of Geochemistry at Bristol's School of Earth Sciences who led the research team, said: "The data show that deep ocean circulation can change surprisingly rapidly, and that this can rapidly release CODr James Rae at St Andrew's School of Earth and Environmental Sciences, added: "The corals act as a time machine, allowing us to see changes in ocean circulation that happened thousands of years ago."They show that the ocean round Antarctica can suddenly switch its circulation to deliver burps of COScientists have suspected that the Southern Ocean played an important role in ending the last ice age and the team's findings add weight to this idea.Dr Tao Li of Nanjing University, lead author of the new study, said: "There is no doubt that Southern Ocean processes must have played a critical role in these rapid climate shifts and the fossil corals provide the only possible way to examine Southern Ocean processes on these timescales."In another study published in Andrea Burke at St Andrew's School of Earth and Environmental Sciences, added: "There have been some suggestions that reservoirs of carbon deep in marine mud might bubble up and add CODr Tianyu Chen of Nanjing University said: "Our robust reconstructions of radiocarbon at intermediate depths yields powerful constraints on mixing between the deep and upper ocean, which is important for modelling changes in circulation and carbon cycle during the last ice age termination.Dr James Rae added: "Although the rise in CO
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016145841.htm
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A controllable membrane to pull carbon dioxide out of exhaust streams
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A new system developed by chemical engineers at MIT could provide a way of continuously removing carbon dioxide from a stream of waste gases, or even from the air. The key component is an electrochemically assisted membrane whose permeability to gas can be switched on and off at will, using no moving parts and relatively little energy.
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The membranes themselves, made of anodized aluminum oxide, have a honeycomb-like structure made up of hexagonal openings that allow gas molecules to flow in and out when in the open state. However, gas passage can be blocked when a thin layer of metal is electrically deposited to cover the pores of the membrane. The work is described in the journal This new "gas gating" mechanism could be applied to the continuous removal of carbon dioxide from a range of industrial exhaust streams and from ambient air, the team says. They have built a proof-of-concept device to show this process in action.The device uses a redox-active carbon-absorbing material, sandwiched between two switchable gas gating membranes. The sorbent and the gating membranes are in close contact with each other and are immersed in an organic electrolyte to provide a medium for zinc ions to shuttle back and forth. These two gating membranes can be opened or closed electrically by switching the polarity of a voltage between them, causing ions of zinc to shuttle from one side to the other. The ions simultaneously block one side, by forming a metallic film over it, while opening the other, by dissolving its film away.When the sorbent layer is open to the side where the waste gases are flowing by, the material readily soaks up carbon dioxide until it reaches its capacity. The voltage can then be switched to block off the feed side and open up the other side, where a concentrated stream of nearly pure carbon dioxide is released.By building a system with alternating sections of membrane that operate in opposite phases, the system would allow for continuous operation in a setting such as an industrial scrubber. At any one time, half of the sections would be absorbing the gas while the other half would be releasing it."That means that you have a feed stream coming into the system at one end and the product stream leaving from the other in an ostensibly continuous operation," Hatton says. "This approach avoids many process issues" that would be involved in a traditional multicolumn system, in which adsorption beds alternately need to be shut down, purged, and then regenerated, before being exposed again to the feed gas to begin the next adsorption cycle. In the new system, the purging steps are not required, and the steps all occur cleanly within the unit itself.The researchers' key innovation was using electroplating as a way to open and close the pores in a material. Along the way the team had tried a variety of other approaches to reversibly close pores in a membrane material, such as using tiny magnetic spheres that could be positioned to block funnel-shaped openings, but these other methods didn't prove to be efficient enough. Metal thin films can be particularly effective as gas barriers, and the ultrathin layer used in the new system requires a minimal amount of the zinc material, which is abundant and inexpensive."It makes a very uniform coating layer with a minimum amount of materials," Liu says. One significant advantage of the electroplating method is that once the condition is changed, whether in the open or closed position, it requires no energy input to maintain that state. Energy is only required to switch back again.Potentially, such a system could make an important contribution toward limiting emissions of greenhouse gases into the atmosphere, and even direct-air capture of carbon dioxide that has already been emitted.While the team's initial focus was on the challenge of separating carbon dioxide from a stream of gases, the system could actually be adapted to a wide variety of chemical separation and purification processes, Hatton says."We're pretty excited about the gating mechanism. I think we can use it in a variety of applications, in different configurations," he says. "Maybe in microfluidic devices, or maybe we could use it to control the gas composition for a chemical reaction. There are many different possibilities."
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016143056.htm
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Arctic Ocean sediments reveal permafrost thawing during past climate warming
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Sea floor sediments of the Arctic Ocean can help scientists understand how permafrost responds to climate warming. A multidisciplinary team from Stockholm University has found evidence of past permafrost thawing during climate warming events at the end of the last ice age. Their findings, published in
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Arctic permafrost stores more carbon than the atmosphere does. When permafrost thaws, this carbon may be converted to greenhouse gases (CO"Our new study shows for the first time the full history of how warming at the end of the last ice age triggered permafrost thawing in Siberia. This also suggests the release of large quantities of greenhouse gases," says Jannik Martens, PhD student at Stockholm University and lead author of the study. "It appears likely that past permafrost thawing at times of climate warming, about 14,700 and 11,700 years ago, was in part also related to the increase in COIn the current study, the scientists used an eight meters long sediment core that was recovered from the sea floor more than 1,000 meters below the surface of the Arctic Ocean during the SWERUS-C3 expedition onboard the Swedish icebreaker Oden back in 2014. To reconstruct permafrost thawing on land, the scientists applied radiocarbon (14C) dating and molecular analysis to trace organic remains that once were released by thawing permafrost and then washed into the Arctic Ocean."From this core we also learned that erosion of permafrost coastlines was an important driving force for permafrost destruction at the end of the last ice age. Coastal erosion continues to the present day, though ten times slower than during these earlier rapid warming period. With the recent warming trends, however, we see again an acceleration of coastal erosion in some parts of the Arctic, which is expected to release greenhouse gases by degradation of the released organic matter," says Örjan Gustafsson, Professor at Stockholm University and leader of the research program. "Any release from thawing permafrost mean that there is even less room for anthropogenic greenhouse gas release in the earth-climate system budget before dangerous thresholds are reached. The only way to limit permafrost-related greenhouse gas releases is to mitigate climate warming by lowering anthropogenic greenhouse gas emissions."Gustafsson, Martens and their colleagues are now again in the Arctic Ocean as part of the International Siberian Shelf Study (ISSS-2020) onboard the Russian research vessel Akademik Keldysh. The expedition left the port of Arkhangelsk on September 26 and is currently in the East Siberian Sea, seeking more answers to how changing climate may trigger release of carbon, including greenhouse gases, from Arctic permafrost systems, including coastal erosion and permafrost below the sea bottom preserved from the past ice age.
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016143049.htm
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Ground-breaking discovery finally proves rain really can move mountains
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A pioneering technique which captures precisely how mountains bend to the will of raindrops has helped to solve a long-standing scientific enigma.
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The dramatic effect rainfall has on the evolution of mountainous landscapes is widely debated among geologists, but new research led by the University of Bristol and published today in Its findings, which focused on the mightiest of mountain ranges -- the Himalaya -- also pave the way for forecasting the possible impact of climate change on landscapes and, in turn, human life.Lead author Dr Byron Adams, Royal Society Dorothy Hodgkin Fellow at the university's Cabot Institute for the Environment, said: "It may seem intuitive that more rain can shape mountains by making rivers cut down into rocks faster. But scientists have also believed rain can erode a landscape quickly enough to essentially 'suck' the rocks out of the Earth, effectively pulling mountains up very quickly."Both these theories have been debated for decades because the measurements required to prove them are so painstakingly complicated. That's what makes this discovery such an exciting breakthrough, as it strongly supports the notion that atmospheric and solid earth processes are intimately connected."While there is no shortage of scientific models aiming to explain how the Earth works, the greater challenge can be making enough good observations to test which are most accurate.The study was based in the central and eastern Himalaya of Bhutan and Nepal, because this region of the world has become one of the most sampled landscapes for erosion rate studies. Dr Adams, together with collaborators from Arizona State University (ASU) and Louisiana State University, used cosmic clocks within sand grains to measure the speed at which rivers erode the rocks beneath them."When a cosmic particle from outer space reaches Earth, it is likely to hit sand grains on hillslopes as they are transported toward rivers. When this happens, some atoms within each grain of sand can transform into a rare element. By counting how many atoms of this element are present in a bag of sand, we can calculate how long the sand has been there, and therefore how quickly the landscape has been eroding," Dr Adams said."Once we have erosion rates from all over the mountain range, we can compare them with variations in river steepness and rainfall. However, such a comparison is hugely problematic because each data point is very difficult to produce and the statistical interpretation of all the data together is complicated."Dr Adams overcame this challenge by combining regression techniques with numerical models of how rivers erode."We tested a wide variety of numerical models to reproduce the observed erosion rate pattern across Bhutan and Nepal. Ultimately only one model was able to accurately predict the measured erosion rates," Dr Adams said."This model allows us for the first time to quantify how rainfall affects erosion rates in rugged terrain."Research collaborator Professor Kelin Whipple, Professor of Geology at ASU, said: "Our findings show how critical it is to account for rainfall when assessing patterns of tectonic activity using topography, and also provide an essential step forward in addressing how much the slip rate on tectonic faults may be controlled by climate-driven erosion at the surface."The study findings also carry important implications for land use management, infrastructure maintenance, and hazards in the Himalaya.In the Himalaya, there is the ever-present risk that high erosion rates can drastically increase sedimentation behind dams, jeopardising critical hydropower projects. The findings also suggest greater rainfall can undermine hillslopes, increasing the risk of debris flows or landslides, some of which may be large enough to dam the river creating a new hazard -- lake outburst floods.Dr Adams added: "Our data and analysis provides an effective tool for estimating patterns of erosion in mountainous landscapes such as the Himalaya, and thus, can provide invaluable insight into the hazards that influence the hundreds of millions of people who live within and at the foot of these mountains."The research was funded by the Royal Society, the UK Natural Environmental Research Council (NERC), and the National Science Foundation (NSF) of the US.Building on this important research, Dr Adams is currently exploring how landscapes respond after large volcanic eruptions."This new frontier of landscape evolution modelling is also shedding new light on volcanic processes. With our cutting-edge techniques to measure erosion rates and rock properties, we will be able to better understand how rivers and volcanoes have influenced each other in the past," Dr Adams said."This will help us to more accurately anticipate what is likely to happen after future volcanic eruptions and how to manage the consequences for communities living nearby."
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016132015.htm
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Supercomputing study breaks ground for tree mapping, carbon research
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Scientists from NASA's Goddard Space Flight Center in Greenbelt, Maryland, and international collaborators demonstrated a new method for mapping the location and size of trees growing outside of forests, discovering billions of trees in arid and semi-arid regions and laying the groundwork for more accurate global measurement of carbon storage on land.
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Using powerful supercomputers and machine learning algorithms, the team mapped the crown diameter -- the width of a tree when viewed from above -- of more than 1.8 billion trees across an area of more than 500,000 square miles, or 1,300,000 square kilometers. The team mapped how tree crown diameter, coverage, and density varied depending on rainfall and land use.Mapping non-forest trees at this level of detail would take months or years with traditional analysis methods, the team said, compared to a few weeks for this study. The use of very high-resolution imagery and powerful artificial intelligence represents a technology breakthrough for mapping and measuring these trees. This study is intended to be the first in a series of papers whose goal is not only to map non-forest trees across a wide area, but also to calculate how much carbon they store -- vital information for understanding the Earth's carbon cycle and how it is changing over time.Carbon is one of the primary building blocks for all life on Earth, and this element circulates among the land, atmosphere, and oceans via the carbon cycle. Some natural processes and human activities release carbon into the atmosphere, while other processes draw it out of the atmosphere and store it on land or in the ocean. Trees and other green vegetation are carbon "sinks," meaning they use carbon for growth and store it out of the atmosphere in their trunks, branches, leaves and roots. Human activities, like burning trees and fossil fuels or clearing forested land, release carbon into the atmosphere as carbon dioxide, and rising concentrations of atmospheric carbon dioxide are a main cause of climate change.Conservation experts working to mitigate climate change and other environmental threats have targeted deforestation for years, but these efforts do not always include trees that grow outside forests, said Compton Tucker, senior biospheric scientist in the Earth Sciences Division at NASA Goddard. Not only could these trees be significant carbon sinks, but they also contribute to the ecosystems and economies of nearby human, animal and plant populations. However, many current methods for studying trees' carbon content only include forests, not trees that grow individually or in small clusters.Tucker and his NASA colleagues, together with an international team, used commercial satellite images from DigitalGlobe, which were high-resolution enough to spot individual trees and measure their crown size. The images came from the commercial QuickBird-2, GeoEye-1, WorldView-2, and WorldView-3 satellites. The team focused on the dryland regions -- areas that receive less precipitation than what evaporates from plants each year -- including the arid south side of the Sahara Desert, that stretches through the semi-arid Sahel Zone and into the humid sub-tropics of West Africa. By studying a variety of landscapes from few trees to nearly forested conditions, the team trained their computing algorithms to recognize trees across diverse terrain types, from deserts in the north to tree savannas in the south.The team ran a powerful computing algorithm called a fully convolutional neural network ("deep learning") on the University of Illinois' Blue Waters, one of the world's fastest supercomputers. The team trained the model by manually marking nearly 90,000 individual trees across a variety of terrain, then allowing it to "learn" which shapes and shadows indicated the presence of trees.The process of coding the training data took more than a year, said Martin Brandt, an assistant professor of geography at the University of Copenhagen and the study's lead author. Brandt marked all 89,899 trees by himself and helped supervise training and running the model. Ankit Kariryaa of the University of Bremen led the development of the deep learning computer processing."In one kilometer of terrain, say it's a desert, many times there are no trees, but the program wants to find a tree," Brandt said. "It will find a stone, and think it's a tree. Further south, it will find houses that look like trees. It sounds easy, you'd think -- there's a tree, why shouldn't the model know it's a tree? But the challenges come with this level of detail. The more detail there is, the more challenges come."Establishing an accurate count of trees in this area provides vital information for researchers, policymakers and conservationists. Additionally, measuring how tree size and density vary by rainfall -- with wetter and more populated regions supporting more and larger trees -- provides important data for on-the-ground conservation efforts."There are important ecological processes, not only inside, but outside forests too," said Jesse Meyer, a programmer at NASA Goddard who led the processing on Blue Waters. "For preservation, restoration, climate change, and other purposes, data like these are very important to establish a baseline. In a year or two or ten, the study could be repeated with new data and compared to data from today, to see if efforts to revitalize and reduce deforestation are effective or not. It has quite practical implications."After gauging the program's accuracy by comparing it to both manually coded data and field data from the region, the team ran the program across the full study area. The neural network identified more than 1.8 billion trees -- surprising numbers for a region often assumed to support little vegetation, said Meyer and Tucker."Future papers in the series will build on the foundation of counting trees, extend the areas studied, and look ways to calculate their carbon content," said Tucker. NASA missions like the Global Ecosystem Dynamics Investigation mission, or GEDI, and ICESat-2, or the Ice, Cloud, and Land Elevation Satellite-2, are already collecting data that will be used to measure the height and biomass of forests. In the future, combining these data sources with the power of artificial intelligence could open up new research possibilities."Our objective is to see how much carbon is in isolated trees in the vast arid and semi-arid portions of the world," Tucker said. "Then we need to understand the mechanism which drives carbon storage in arid and semi-arid areas. Perhaps this information can be utilized to store more carbon in vegetation by taking more carbon dioxide out of the atmosphere.""From a carbon cycle perspective, these dry areas are not well mapped, in terms of what density of trees and carbon is there," Brandt said. "It's a white area on maps. These dry areas are basically masked out. This is because normal satellites just don't see the trees -- they see a forest, but if the tree is isolated, they can't see it. Now we're on the way to filling these white spots on the maps. And that's quite exciting."
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016123916.htm
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Are climate scientists being too cautious when linking extreme weather to climate change?
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In this year of extreme weather events -- from devastating West Coast wildfires to tropical Atlantic storms that have exhausted the alphabet -- scientists and members of the public are asking when these extreme events can be scientifically linked to climate change.
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Dale Durran, a professor of atmospheric sciences at the University of Washington, argues that climate science need to approach this question in a way similar to how weather forecasters issue warnings for hazardous weather.In a new paper, published in the October issue of the Most current approaches to attributing extreme weather events to global warming, he says, such as the conditions leading to the ongoing Western wildfires, focus on the likelihood of raising a false alarm. Scientists do this by using statistics to estimate the increase in the probability of that event that is attributable to climate change. Those statistical measures are closely related to the "false alarm ratio," an important metric used to assess the quality of hazardous weather warnings.But there is a second key metric used to assess the performance of weather forecasters, he argues: The probably that the forecast will correctly warn of events that actually occur, known as the "probability of detection." The ideal probability of detection score is 100%, while the ideal false-alarm rate would be zero.Probability of detection has mostly been ignored when it comes to linking extreme events to climate change, he says. Yet both weather forecasting and climate change attribution face a tradeoff between the two. In both weather forecasting and climate-change attribution, calculations in the paper show that raising the thresholds to reduce false alarms produces a much greater drop in the probability of detection.Drawing on a hypothetical example of a tornado forecaster whose false alarm ratio is zero, but is accompanied by a low probability of detection, he writes that such an "overly cautious tornado forecasting strategy might be argued by some to be smart politics in the context of attributing extreme events to global warming, but it is inconsistent with the way meteorologists warn for a wide range of hazardous weather, and arguably with the way society expects to be warned about threats to property and human life."Why does this matter? The paper concludes by noting: "If a forecaster fails to warn for a tornado there may be serious consequences and loss of life, but missing the forecast does not make next year's tornadoes more severe. On the other hand, every failure to alert the public about those extreme events actually influenced by global warming facilitates the illusion that humankind has time to delay the actions required to address the source of that warming. Because the residence time of CO2 in the atmosphere is many hundreds to thousands of years the cumulative consequences of such errors can have a very long lifetime."
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016114930.htm
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Long-term data show a recent acceleration in chemical and physical changes in the ocean
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New research published in
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The study utilized datasets from Hydrostation 'S' and the Bermuda Atlantic Time-series Study (BATS) projects at the Bermuda Institute of Ocean Sciences (BIOS). Both are led by Professor Nicholas Bates, BIOS senior scientist and the projects' principal investigator (PI), and Rod Johnson, BIOS assistant scientist and the projects' co-PI. Together, these time-series represent the two longest continuous records of data from the global open ocean."The four decades of data from BATS and Hydrostation 'S' show that the ocean is not changing uniformly over time and that the ocean carbon sink is not stable over recent time with variability from decade to decade," Bates said.Of the two sites, Hydrostation 'S' is the oldest, located approximately 15 miles (25 km) southeast of Bermuda and consisting of repeat biweekly hydrographic observations of temperature, salinity, and dissolved oxygen conducted through the water column since 1954. The Bermuda Atlantic Time-series Study (BATS) site is located approximately 50 miles (80 km) southeast of Bermuda. It consists of monthly sampling of the physics, chemistry, and biology of the entire water column since 1988. The study's datasets represent more than 1381 cruises to Hydrostation 'S' from 1954 to 2020 and more than 450 cruises to BATS from 1988 to the end of 2019.Results showed that, over the last 40 years, surface temperatures in the Sargasso Sea have increased by 0.85 +/- 0.12oC, with the summer surface temperatures rising at a higher rate than winter. Additionally, the winter (<22°C) ocean state has gotten shorter by almost a month, while the summer season (with waters warmer than 25°C) has gotten longer. During the same period, surface salinity also increased by ~0.11 +/- 0.02. Importantly, these data show evidence of decadal variability; however, during the last decade (2010-2019), rapid warming of 1.18oC and salinification of 0.14 has occurred.The data also show a trend of dissolved oxygen (DO) decline in the Sargasso Sea since the 1980s, representing a loss of ~2% per decade. Given the ocean warming observed in the Sargasso Sea, the researchers estimate that the warming impact on DO solubility would likely have contributed to about 13% of the total decline of DO over the past nearly 40 years. The remaining deoxygenation (~87%) must have resulted from the combined effect of changes in ocean biology and physics.The BATS and Hydrostation 'S' time-series data allow direct detection of the ocean acidification signal in the surface waters of the North Atlantic Ocean. The typical pH range of surface waters in the 1980s ranged from wintertime highs of ~8.2 to summertime lows of ~8.08-8.10, with the ocean remaining mildly alkaline at present (~7.98-8.05). The rate of pH change is ~0.0019 +/- 0.0001 year-1, which is a more negative rate than previously reported and represents a 20% increase in hydrogen ion concentration since 1983. These changes were accompanied with significant increases of dissolved inorganic carbon and CO"In forty years, seawater COThe observations off Bermuda reveal the substantial decadal variations and highlight the need for long-term data to determine trends in other ocean physical and biogeochemical properties, particularly when linking local measurements to basin-scale changes. Long-term data on ocean chemistry and physical from time-series sites such as Hydrostation 'S' and BATS provide critically needed and unparalleled observations that, when coupled with ocean-atmosphere models, allow for a more complete understanding of drivers of the global carbon cycle.
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016114927.htm
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World's greatest mass extinction triggered switch to warm-bloodedness
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Mammals and birds today are warm-blooded, and this is often taken as the reason for their great success.
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University of Bristol palaeontologist Professor Mike Benton, identifies in the journal The Permian-Triassic mass extinction killed as much as 95 per cent of life, and the very few survivors faced a turbulent world, repeatedly hit by global warming and ocean acidification crises. Two main groups of tetrapods survived, the synapsids and archosaurs, including ancestors of mammals and birds respectively.Palaeontologists had identified indications of warm-bloodedness, or technically endothermy, in these Triassic survivors, including evidence for a diaphragm and possible whiskers in the synapsids.More recently, similar evidence for early origin of feathers in dinosaur and bird ancestors has come to light. In both synapsids and archosaurs of the Triassic, the bone structure shows characteristics of warm-bloodedness. The evidence that mammal ancestors had hair from the beginning of the Triassic has been suspected for a long time, but the suggestion that archosaurs had feathers from 250 million years ago is new.But a strong hint for this sudden origin of warm-bloodedness in both synapsids and archosaurs at exactly the time of the Permian-Triassic mass extinction was found in 2009. Tai Kubo, then a student studying the Masters in Palaeobiology degree at Bristol and Professor Benton identified that all medium-sized and large tetrapods switched from sprawling to erect posture right at the Permian-Triassic boundary.Their study was based on fossilised footprints. They looked at a sample of hundreds of fossil trackways, and Kubo and Benton were surprised to see the posture shift happened instantly, not strung out over tens of millions of years, as had been suggested. It also happened in all groups, not just the mammal ancestors or bird ancestors.Professor Benton said: "Modern amphibians and reptiles are sprawlers, holding their limbs partly sideways."Birds and mammals have erect postures, with the limbs immediately below their bodies. This allows them to run faster, and especially further. There are great advantages in erect posture and warm-bloodedness, but the cost is that endotherms have to eat much more than cold-blooded animals just to fuel their inner temperature control."The evidence from posture change and from early origin of hair and feathers, all happening at the same time, suggested this was the beginning of a kind of 'arms race'. In ecology, arms races occur when predators and prey have to compete with each other, and where there may be an escalation of adaptations. The lion evolves to run faster, but the wildebeest also evolves to run faster or twist and turn to escape.Something like this happened in the Triassic, from 250 to 200 million years ago. Today, warm-blooded animals can live all over the Earth, even in cold areas, and they remain active at night. They also show intensive parental care, feeding their babies and teaching them complex and smart behaviour. These adaptations gave birds and mammals the edge over amphibians and reptiles and in the present cool world allowed them to dominate in more parts of the world.Professor Benton added: "The Triassic was a remarkable time in the history of life on Earth. You see birds and mammals everywhere on land today, whereas amphibians and reptiles are often quite hidden."This revolution in ecosystems was triggered by the independent origins of endothermy in birds and mammals, but until recently we didn't realise that these two events might have been coordinated."That happened because only a tiny number of species survived the Permian-Triassic mass extinction -- who survived depended on intense competition in a tough world. Because a few of the survivors were already endothermic in a primitive way, all the others had to become endothermic to survive in the new fast-paced world."
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016100918.htm
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Energy system 2050: Solutions for the energy transition
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To contribute to global climate protection, Germany has to rapidly and comprehensively minimize the use of fossil energy sources and to transform the energy system accordingly. The Helmholtz Association's research initiative "Energy System 2050" has studied how and by which means this can be achieved. One of the partners is Karlsruhe Institute of Technology (KIT). At the final conference in Berlin, scientists of the participating research centers presented their results.
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Having decided to achieve climate neutrality by 2050, Germany as an industrialized country is facing a tremendous challenge: Organizing a comprehensive and sustainable transformation of the energy system while ensuring stable energy supply for our everyday life, for industry, and for the operation of central communication and transport infrastructures. Within the framework of the research initiative "Energy System 2050" (ES2050), scientists of the Helmholtz Association have developed concrete strategies and technical approaches to both improving climate protection and enhancing supply security. These have already been picked up by politics and industry."Climate-friendly transformation of the energy system requires adequate technologies and clear systemic solutions. Within 'Energy System 2050,' we have not only succeeded in developing them. We have also tested them in real operation and elaborated flexible strategies for their use," says Professor Holger Hanselka, coordinator of the research initiative, Research Field Coordinator Energy of the Helmholtz Association, and President of KIT. "Our research initiative pools the competencies of eight research centers to make the energy transition a success."Professor Otmar D. Wiestler, President of the Helmholtz Association, says: "Local, national, and international energy systems have to be switched to renewable energy sources as quickly as possible. This not only is an important step to cope with climate change and increasing degradation of the environment. With the help of regenerative energy systems, we can also produce energy at low costs without being dependent on imports. The 'Energy System 2050' initiative clearly shows which fundamental contributions can be made by the Helmholtz Association in line with its mission to conduct cutting-edge research for solving grand challenges facing society."The research initiative was launched in 2015 to make a relevant and forward-looking contribution to the transformation of the energy system. 170 scientists conducted research in teams that focused on a piece of the energy transition puzzle each. Based on a systemic analysis of the German energy supply system, they developed economically efficient and climate-friendly transformation paths until 2050. This work was complemented by research into the architecture and security of the future power grid and integration of hydrogen and biogenic energy sources in the energy system. Moreover, power grid components, such as redox flow storage systems, biogas facilities, or gas turbines for the reconversion of synthesis gas and biogas were subjects of studies. Researchers tested the technologies in detail and systemically analyzed their interaction. As a result, the best "team players" for sector coupling were found, including technologies to combine heat and power supply. In addition, lifecycle-oriented sustainability analyses were made. Apart from costs and CO2 emissions, such analyses consider other ecological and social factors when producing fuel from biogenic residues, for instance.To carry out dynamic experiments on the system level, the researchers of ES2050 established a large-scale network of research infrastructures, including the Energy Lab 2.0 on the campus of KIT and the Living Lab Energy Campus of Forschungszentrum Jülich (FZJ). These detailed models of the energy system have meanwhile been equipped with own grid infrastructures and power-to-x facilities, residential buildings, and transport system components. The physical models are closely interlinked with virtual structures for the smart extension of the energy system. With the help of "digital twins," it is possible to integrate system components in experiments, although they do not yet exist -- for instance, the future hydrogen infrastructure. The research initiative understands its modeling tools, datasets, and benchmarks as parts of an open ecosystem and makes them available as open sources. This "toolkit for the energy transition" is used by large transmission grid operators already.It is still a long way to go to climate neutrality in the energy sector, but change has started: In 2019, for instance, the share of renewable energy sources in gross power consumption was 42.1 percent, in the year before 37.8 percent, according to the Federal Environment Agency. The results of the research initiative "Energy System 2050" can enhance this dynamic trend and extend it to cover the housing, transport, and industry sectors. The research initiative "Energy System 2050" was launched by the research field Energy of the Helmholtz Association. The partners are the KIT, the German Aerospace Center (DLR), Forschungszentrum Jülich (FZJ), the Helmholtz Centre Potsdam (GFZ), the Helmholtz Centre Berlin (HZB), the Helmholtz Centre Dresden-Rossendorf (HZDR), the Max Planck Institute for Plasma Physics (IPP -- associated), and the Helmholtz Centre for Environmental Research (UFZ).
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Climate
| 2,020 |
October 16, 2020
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https://www.sciencedaily.com/releases/2020/10/201016092452.htm
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Unprecedented energy use since 1950 has transformed humanity's geologic footprint
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A new study coordinated by CU Boulder makes clear the extraordinary speed and scale of increases in energy use, economic productivity and global population that have pushed the Earth towards a new geological epoch, known as the Anthropocene. Distinct physical, chemical and biological changes to Earth's rock layers began around the year 1950, the research found.
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Led by Jaia Syvitski, CU Boulder professor emerita and former director of the Institute of Alpine Arctic Research (INSTAAR), the paper, published today in "This is the first time that scientists have documented humanity's geological footprint on such a comprehensive scale in a single publication," said Syvitski, former executive director of the Community Surface Dynamics Modeling System, a diverse community of international experts from who study the interactions between the Earth's surface, water and atmosphere.In the past 70 years, humans have exceeded the energy consumption of the entire preceding 11,700 years -- largely through combustion of fossil fuels. This huge increase in energy consumption has then allowed for a dramatic increase in human population, industrial activity, pollution, environmental degradation and climate change.The study is the result of work by the Anthropocene Working Group (AWG), an interdisciplinary group of scientists analyzing the case for making the Anthropocene a new epoch within the official Geological Time Scale, characterized by the overwhelming human impact on the Earth.The word Anthropocene follows the naming convention for assigning geologically defined lengths of time and has come to embody the present time during which humans are dominating planetary-scale Earth systems.In geological time, an epoch is longer than an Age but shorter than a Period, measured in tens of millions of years. Within the Holocene epoch, there are several Ages -- but the Anthropocene is proposed as a separate Epoch within Earth's planetary history."It takes a lot to change the Earth's system," said Syvitski. "Even if we were to get into a greener world where we were not burning fossil fuels, the main culprit of greenhouse gases, we would still have a record of an enormous change on our planet."The 18 authors of the study compiled existing research to highlight 16 major planetary impacts caused by increased energy consumption and other human activities, spiking in significance around or since 1950.Between 1952 and 1980, humans set off more than 500 thermonuclear explosions above ground as part of global nuclear weapons testing, which have forever left a clear signature of human-caused radionuclides -- atoms with excess nuclear energy -- on or near the surface of the entire planet.Since about 1950, humans have also doubled the amount of fixed nitrogen on the planet through industrial production for agriculture, created a hole in the ozone layer through the industrial scale release of chlorofluorocarbons (CFCs), released enough greenhouse gasses from fossil fuels to cause planetary level climate change, created tens of thousands more synthetic mineral-like compounds than naturally occur on Earth and caused almost one-fifth of river sediment worldwide to no longer reach the ocean due to dams, reservoirs and diversions.Humans have produced so many millions of tons of plastic each year since the middle of the 20th century that microplastics are "forming a near-ubiquitous and unambiguous marker of Anthropocene," according to the study.Not all of these planetary level changes may define the Anthropocene geologically, according to Syvitski and her co-authors, but if present trends continue, they can lead to markers in the rock record that will.Syvitski credits her time as director of INSTAAR from 1995 to 2007 for enabling her to bring together scientists from the different environmental disciplines needed for the study, including geology, biology, geography, anthropology and history.In a similar way, she sees a need for people of different backgrounds and experiences around the world to come together to work toward solutions."We humans collectively got ourselves into this mess, we need to work together to reverse these environmental trends and dig ourselves out of it," said Syvitski. "Society shouldn't feel complacent. Few people who read the manuscript should come away without emotions bubbling up, like rage, grief and even fear."
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Climate
| 2,020 |
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