Date
stringlengths 11
18
| Link
stringlengths 62
62
| Title
stringlengths 16
148
| Summary
stringlengths 1
2.68k
| Body
stringlengths 22
13k
⌀ | Category
stringclasses 20
values | Year
int64 2k
2.02k
|
|---|---|---|---|---|---|---|
February 16, 2021 | https://www.sciencedaily.com/releases/2021/02/210216115037.htm | Quantum leaps in understanding how living corals survive | Coral reefs have thrived for millions of years in their shallow ocean water environments due to their unique partnerships with the algae that live in their tissues. Corals provide a safe haven and carbon dioxide while their algal symbionts provide them with food and oxygen produced from photosynthesis. Using the corals Orbicella annularis and Orbicella faveolate in the southern Caribbean, researchers at the Carl R. Woese Institute for Genomic Biology (IGB) have improved our ability to visualize and track these symbiotic interactions in the face of globally warming sea surface temperatures and deepening seawaters. | "Corals are one of the most resilient organisms on the planet," said Mayandi Sivaguru, the co-lead author of the study and Assistant Director of Core Facilities at the IGB. "They have survived ice ages, greenhouse conditions with no ice, and everything else in between that the planet has thrown at them."Although they have a long history of weathering disruptions, coral reefs are also sensitive enough to serve as indicators of climate change and oceanic health. As an example, when the sea surface temperature or the seawater acidity increases, corals eject their algal partners -- a phenomenon called coral bleaching -- which converts the corals from green to white. To understand why bleaching occurs, it is important to visualize how the corals interact with their algal partners.Previously, researchers had to peel the skin of corals and place the samples in a blender to study their symbiotic algal partners. The current study uses a non-invasive technique instead. "We collect small samples of corals on the living reef, bring them back to Illinois, and look at them under the microscope without further processing. Two-photon microscopy allows us to look at their three-dimensional structure, and determine how many algae and what biomolecules are present," Sivaguru said. The technique uses light to scan living tissues, allowing the researchers to keep the corals in their original growth structure.The researchers used these new methods to compare the symbionts in two environmental contexts. The first was from shallow to deeper seawater and the second was between seasonal warm-to-cool changes in sea surface temperatures. "In addition to analyzing the number of symbionts in the coral tissues, which the corals can alter, we also tracked simultaneous changes in mucus and biomolecules produced by the corals, some of which serve as a natural sun block," Sivaguru said.The microscopy studies revealed that shallow water corals have lower algal concentrations and produce higher levels of chromatophores, which are biomolecules that protect algae from sunlight damage. On the other hand, the researchers found the opposite pattern in deeper water corals. These corals receive lesser sunlight and would therefore require more algae to keep up with the photosynthetic demand. During seasonal sea surface temperature changes, the warmer water caused decreased mucus production and algal concentrations, but increased photosynthesis and coral skeleton growth. Conversely, cooler waters caused the opposite effect."We have combined the results of this study to identify universal mechanisms of biomineralization found between water, microbes, living organisms, and rock," said Lauren Todorov, the co-lead author, who completed this research as part of her undergraduate B.Sc. thesis at Illinois and is now completing her M.Sc. in Geology. "This study has allowed us to establish a comprehensive understanding of the coral system as well as make connections to the formation of layered rock in other systems such as hot springs, roman aqueducts, and even human kidney stones.""This project required several years to complete and required virtually all of the microscopes available in the IGB Core Facilities. Importantly, our research team included several students who worked on the project starting in high school and continued as part of their undergraduate and graduate research in institutions across the United States. This included fieldwork in Curaçao and well as work at the IGB," said Bruce Fouke (BCXT), a professor of geology and microbiology at the IGB.The work was funded by the Office of Naval Research, the IGB Undergraduate Summer Research Fellowship, the IGB Mark Tracy Fellowship for Translational Research, the Department of Molecular and Cellular Biology Jenner Family Summer Research Fellowship, and the Edward and Barbara Weil Research Fund. | Climate | 2,021 |
February 16, 2021 | https://www.sciencedaily.com/releases/2021/02/210216115012.htm | Despite sea-level rise risks, migration to some threatened coastal areas may increase | In coming decades as coastal communities around the world are expected to encounter sea-level rise, the general expectation has been that people's migration toward the coast will slow or reverse in many places. | However, new research co-authored by Princeton University shows that migration to the coast could actually accelerate in some places despite sea-level change, contradicting current assumptions.The research, published in Meanwhile, the populations already living along the coast tend to stay, as floods increase their losses but few better alternatives are present elsewhere."We tend to think that rising sea levels will drive people away from the coasts, but here we show a plausible story where they don't," said lead author Andrew R. Bell, assistant professor of environmental studies at New York University."We show that people may choose to migrate into riskier terrain, a finding that contradicts common assumptions," said Michael Oppenheimer, a coauthor and Albert G. Milbank Professor of Geosciences and International Affairs and the High Meadows Environmental Institute, and director of Princeton's Center for Policy Research on Energy and the Environment. "It's why this kind of modeling matters so much. Getting a better grasp on what people will decide to do under specific circumstances will inform adaptation planning in time to save lives. The dangers from climate change can only be addressed effectively with planning long in advance by individuals and governments."Improving people's access to financial credit is commonly proposed as a policy lever to incentivize migration away from climate hazards, but surprisingly this new model demonstrated that credit access actually increased the number of people who chose to stay along the coast. The researchers attribute this "mooring" effect to people having fewer opportunities elsewhere and being able to use credit to protect their households along the coast.Access to credit remains an important mechanism for addressing the vulnerability populations experience in light of climate hazards, argue the researchers. However, broadened access to credit alone is not sufficient to address mobility for climate adaptation purposes. This study provides valuable insights into how the timing and delivery of credit can result in particular behavioral responses. Additional policy interventions -- including regulations on zoning and construction, programs to promote savings behavior, or grants to specific businesses -- should be considered in future studies to see if a combination of approaches yields different migration results, according to the researchers.The model developed by the researchers simulated individual migration decisions at household levels and incorporated numerous variables that would push, pull, or stick people to particular locations, including income opportunities, social network ties, land ownership, credit access, risk tolerance, and flood damage exposure. The study analyzed simulations with 4.8 million migrants across 871 scenarios of projected 21st-century coastal flooding under various greenhouse gas emissions pathways."With the MIDAS model, we have been much better able to capture the competing factors -- jobs, family, and investment in a place -- that shape an individual's decision to stay or leave, and compare them on an equal footing," said Bell.This latest study takes an important step toward more nuanced views of human behavior, illuminating potential climate change adaptation responses that initially seemed counterintuitive. To make further improvements on the model, researchers will need to collect more data on how people are adapting to climate shocks as they occur, and more information about people's interpretation of risks at different levels of exposure. These future models could provide more policy-actionable recommendations that avoid some of the dangers of unintended behavioral responses exposed by this current analysis. | Climate | 2,021 |
February 16, 2021 | https://www.sciencedaily.com/releases/2021/02/210216100132.htm | Shrubs and soils: A hot topic in the cool tundra | Climate change is rapid in the Arctic. As the climate warms, shrubs expand towards higher latitudes and altitudes. Researcher Julia Kemppinen together with her colleagues investigated the impacts of dwarf shrubs on tundra soils in the sub-Arctic Fennoscandia. | The study revealed that the dominance of dwarf shrubs impacts soil microclimate and carbon stocks. Microclimate describes the moisture and temperature conditions close to ground surface. Shrubs are the largest plant life form in the Arctic, and in comparison, to other arctic plants, shrubs use more water and cast more shade."The results indicate that the dominance of dwarf shrubs decreases soil moisture, soil temperatures and soil organic carbon stocks," says Kemppinen.Due to climate change, the dominance of dwarf shrubs has increased in the Fennoscandian tundra, especially the evergreen crowberry (Empetrum nigrum). While in other parts of the Arctic, larger deciduous shrubs have increased. This expansion is called shrubification.The carbon cycle links shrubification back to global climate change. When the dominance of shrubs increases, less carbon is stored in the soils compared to other plant communities. The soil carbon stocks are important, because they store carbon that would otherwise be released to the atmosphere."Arctic soils store about half of the global belowground organic carbon pool. If the carbon stocks decrease as the conditions in the Arctic are changing, this may feedback to global climate wawrming. Therefore, everyone should know what is going on in the Arctic," says researcher Anna-Maria Virkkala.Investigating the connections between shrubs and soils requires a lot of data. The researchers collected large field datasets for this study. In addition, the researchers used openly available data produced by the Finnish Meteorological Institute and the National Land Survey of Finland."Although, our research group the BioGeoClimate Modelling Lab collected a lot of data in the field, we couldn't have done this study without high-quality, open data," says professor Miska Luoto from the University of Helsinki. | Climate | 2,021 |
February 16, 2021 | https://www.sciencedaily.com/releases/2021/02/210216092853.htm | First humans in Tasmania must have seen spectacular auroras | Drilling a 270,000-year old core from a Tasmanian lake has provided the first Australian record of a major global event where the Earth's magnetic field 'switched '- and the opportunity to establish a precedent for developing new paleomagnetic dating tools for Australian archaeology and paleosciences. | "This is the first study of this kind in Australia since pioneering studies in the 1980s," said author Dr Agathe Lisé-Provonost, a McKenzie Fellow from the School of Earth Sciences at the University of Melbourne."Just two lakes in north-east Australia previously provided such "full-vector" record, where both the past directions and the past intensity of the Earth magnetic field are obtained from the same cores."Published in the journal "During the geomagnetic 'excursion', the strength of the Earth's magnetic field almost vanished," said DrLisé-Provonost."This would lead to a big increase in cosmic and solar particles bombarding our planet because the magnetic field normally acts like a shield."We don't know when the next geomagnetic excursion will happen, but if one was to occur today, satellites would be rendered useless, smartphone navigation apps would fail, and there would be major disruptions of power distribution systems."Research leading to that discovery got underway in 2014 when the author travelled to a small sub-alpine lake in western Tasmania with a team led by Associate Professor Michael-Shawn Fletcher, where a makeshift floating platform rigged to two inflatable rafts was used to drill down into the sediment.With the core containing a climate, vegetation, and paleomagnetic record of the area, the team looked to first accurately date its layers finding evidence of the ecosystem changes that occurred as Tasmanian Aboriginals arrived 43,000 years ago and managed the land over thousands of years. Abrupt changes that occurred since the arrival of Europeans 200 years ago are also evidenced."Magnetic particles are eroded from rocks, making their way to a lake by wind or water, and settle down on the lake bottom," said Dr Lisé-Provonost."The magnetic particles act like tiny compass needles, aligning with the Earth's magnetic field. As these particles accumulate and become buried, they become locked in place, leaving a history of the Earth's magnetic field. The deeper we drill, the further back in time we go."It's hoped the research will lead the way for more studies of the past geomagnetic field behavior from Australian lakes and other geological materials such as lava flows, cave deposits and fired archaeological artefacts, for developing new paleomagnetic dating tools and improving models of the Earth's magnetic field to, one day, maybe predict the next geomagnetic excursion.The research team will now go even further back in time recovering the climate history of Tasmania, with analysing sediments from the 816,000 year-old meteorite impact at Darwin Crater. | Climate | 2,021 |
February 15, 2021 | https://www.sciencedaily.com/releases/2021/02/210215160230.htm | Carbon dioxide dip may have helped dinosaurs walk from South America to Greenland | A new paper refines estimates of when herbivorous dinosaurs must have traversed North America on a northerly trek to reach Greenland, and points out an intriguing climatic phenomenon that may have helped them along the journey. | The study, published in the Previous estimates suggested that sauropodomorphs -- a group of long-necked, herbivorous dinosaurs that eventually included Brontosaurus and Brachiosaurus -- arrived in Greenland sometime between 225 and 205 million years ago. But by painstakingly matching up ancient magnetism patterns in rock layers at fossil sites across South America, Arizona, New Jersey, Europe and Greenland, the new study offers a more precise estimate: It suggests that sauropodomorphs showed up in what is now Greenland around 214 million years ago. At the time, the continents were all joined together, forming the supercontinent Pangea.With this new and more precise estimate, the authors faced another question. Fossil records show that sauropodomorph dinosaurs first appeared in Argentina and Brazil about 230 million years ago. So why did it take them so long to expand into the Northern Hemisphere?"In principle, the dinosaurs could have walked from almost one pole to the other," explained Kent, who is also an emeritus professor at Rutgers University. "There was no ocean in between. There were no big mountains. And yet it took 15 million years. It's as if snails could have done it faster." He calculates that if a dinosaur herd walked only one mile per day, it would take less than 20 years to make the journey between South America and Greenland.Intriguingly, Earth was in the midst of a tremendous dip in atmospheric COAlthough the timing of these two events -- the plummeting COOn Earth, areas around the equator are hot and humid, while adjacent areas in low latitudes tend to be very dry. Kent and Clemmensen say that on a planet supercharged with CO"We know that with higher COBut when the CO"Once they arrived in Greenland, it looked like they settled in,'" said Kent. "They hung around as a long fossil record after that."The idea that a dip in CONext, Kent hopes to continue working to better understand the big CO | Climate | 2,021 |
February 15, 2021 | https://www.sciencedaily.com/releases/2021/02/210215092430.htm | Higher elevation birds sport thicker down | Feathers are a sleek, intricate evolutionary innovation that makes flight possible for birds, but in addition to their stiff, aerodynamic feathers used for flight, birds also keep a layer of soft, fluffy down feathers between their bodies and their outermost feathers to regulate body temperature. | Using the Smithsonian's collection of 625,000 bird specimens, Sahas Barve, a Peter Buck Fellow at the Smithsonian's National Museum of Natural History, led a new study to examine feathers across 249 species of Himalayan songbirds, finding that birds living at higher elevations have more of the fluffy down -- the type of feathers humans stuff their jackets with -- than birds from lower elevations. Published on Feb. 15 in the journal Finding such a clear pattern across so many species underscores how important feathers are to a bird's ability to adapt to its environment and suggests that adding down may be a strategy common to all songbirds, or passerines as they are known to researchers. Furthermore, finding that birds from colder environments tend to have more down may one day help researchers predict which birds are most vulnerable to climate change simply by studying their feathers."The Himalayas are seeing some of the fastest rates of warming on Earth," Barve said. "At the same time, climate change is driving an increase in the frequency and intensity of extremely cold events like snowstorms. Being able to accurately predict the temperatures a bird can withstand could give us a new tool to predict how certain species might respond to climate change."The research was inspired by a tiny bird called a goldcrest during a frigid morning of field work in the Sho-kharkh forest of the Himalayas. Barve found himself wondering how this bird, which weighs about the same as a teaspoon of sugar, was able to flit about the treetops in icy air that was already numbing his fingers. Shoving his hands back into the pockets of his thick down jacket, the question that formed in Barve's mind was "Do Himalayan birds wear down jackets?"To answer that question, Barve and his co-authors used a microscope to take photos of the chest feathers of 1,715 specimens from the Smithsonian's collections representing 249 species from the cold, high-altitude Himalayan Mountains. Then, Barve and his co-authors used those super-detailed photos to determine exactly how long each feather's downy section was relative to its total length. The team was able to do that by looking at the fluffy downy section of each feather close to its base when compared to the streamlined ends of most birds' feathers.After meticulously logging the relative lengths of all those downy sections, Barve analyzed the results and found that the smallest birds and the birds from the highest elevations, where temperatures are at their coldest, tended to have the highest proportion of down on their body feathers. The analysis showed that high-elevation birds had up to 25% more down in their feathers, and the smallest bird had feathers that were three times as long as the largest birds, proportionately to their body size.Past research suggested that birds from colder habitats sported added downy insulation, but Barve said this is the first study to analyze this pattern for such a large number of species in cold environments and across 15,000 feet of elevation."Seeing this correlation across so many species makes our findings more general and lets us say these results suggest all passerine birds may show this pattern," Barve said. "And we never would have been able to look at so many different species and get at this more general pattern of evolution without the Smithsonian's collections."Carla Dove, who runs the museum's Feather Identification Lab and contributed to the study, said she was excited to work together with Barve to use the Smithsonian's collections in a new way. "Sahas looked at more than 1,700 specimens. Having them all in one place in downtown Washington, D.C., as opposed to having to go to the Himalayas and study these birds in the wild, obviously makes a big difference. It allowed him to gather the data he needed quickly before the COVID lockdowns swept the globe, and then work on the analysis remotely."Barve said he is following up this study with experiments looking into just how much insulation birds get from their feathers and then will tie that to the feather's structure and proportion of down. One day, Barve aims to develop a model that will allow scientists to look at the structure of a feather and predict how much insulation it gives the bird -- a capability that could help researchers identify species vulnerable to climate change.Dove said the potential to use these results to eventually understand how some birds might cope with climate change highlights the importance of museum collections. "We have more than 620,000 bird specimens collected over the past 200 years waiting for studies like this. We don't know what our specimens will be used for down the line; that's why we have to maintain them and keep enhancing them. These specimens from the past can be used to predict the future."Funding and support for this research were provided by the Smithsonian. | Climate | 2,021 |
February 12, 2021 | https://www.sciencedaily.com/releases/2021/02/210212145528.htm | More trees do not always create a cooler planet, study shows | New research by Christopher A. Williams, an environmental scientist and professor in Clark University's Graduate School of Geography, reveals that deforestation in the U.S. does not always cause planetary warming, as is commonly assumed; instead, in some places, it actually cools the planet. A peer-reviewed study by Williams and his team, "Climate Impacts of U.S. Forest Loss Span Net Warming to Net Cooling," published Feb. 12 in | It is well established that forests soak up carbon dioxide from the air and store it in wood and soils, slowing the accumulation of greenhouse gases in the atmosphere; however, that is not their only effect on climate. Forests also tend to be darker than other surfaces, said Professor Williams, causing them to absorb more sunlight and retain heat, a process known as "the albedo effect.""We found that in some parts of the country like the Intermountain West, more forest actually leads to a hotter planet when we consider the full climate impacts from both carbon and albedo effects," said Professor Williams. It is important to consider the albedo effect of forests alongside their well-known carbon storage when aiming to cool the planet, he adds.The research was funded by two grants from NASA's Carbon Monitoring System. Williams and his research team -- comprising data scientist Huan Gu, Ph.D. from The Climate Corporation and Tong Jiao, Ph.D. -- found that for approximately one quarter of the country, forest loss causes a persistent net cooling because the albedo effect outweighs the carbon effect. They also discovered that loss of forests east of the Mississippi River and in Pacific Coast states caused planetary warming, while forest loss in the Intermountain and Rocky Mountain West tended to lead to a net cooling.According to Professor Williams, scientists have known for some time that expanding forest cover cannot be assumed to cool the planet or to mitigate global warming. However, this has not always been appreciated broadly."If we fail to consider both the carbon and the albedo effects, large-scale tree-planting initiatives, such as Canada's 2Billion Trees Initiative and The Nature Conservancy's Plant a Billion Trees campaign, could end up placing trees in locations that are counterproductive for cooling the climate system," said Professor Williams."It is all about putting the right trees in the right place," said Williams, "and studies like ours can help identify where the potential for cooling is greatest."Every year, approximately one million acres of forest are being converted to non-forest areas across the lower 48 states of the U.S.; this is largely due to suburban and exurban expansion and development. Professor Williams' team found that the net climate impact of a full 15 years of forest losses amounts to about 17% of a single year of U.S. fossil fuel emissions.Williams' research team used state-of-the-art satellite remote sensing to bring a detailed, observational perspective to examine this problem that had previously been assessed mostly with computer models. The three researchers pinpointed the locations of forest loss and identified what those sites became -- urban, agricultural, grassland, shrubland, pasture, or something else. They then quantified how much forest biomass carbon was released to the atmosphere, and how much additional sunlight was reflected out to space. By comparing these two effects they measured the net impact of deforestation on the climate system.The new datasets and methods used in Professor Williams' study show that the tools are available to take the albedo effect into account. The Clark team hopes to generate actionable datasets to share with land managers and policymakers worldwide within the next one or two years, to help ensure that their tree-planting efforts focus on the right places and have the intended effects. | Climate | 2,021 |
February 12, 2021 | https://www.sciencedaily.com/releases/2021/02/210212111848.htm | Increasing hurricane intensity around Bermuda linked to rising ocean temperatures | New research shows that hurricane maximum wind speeds in the subtropical Atlantic around Bermuda have more than doubled on average over the last 60 years due to rising ocean temperatures in the region. | Hurricanes intensify by extracting energy from the warm ocean surface via air-sea heat fluxes, so a warmer ocean can lead to more intense hurricanes.Improving predictions of wind speeds from hurricanes will help determine the right level of response in advance of the storm and potentially limit the resulting damage in Bermuda.Between 1955 and 2019 mean hurricane intensity near Bermuda, measured by the maximum wind speed, increased from 35 to 73mph -- equivalent to over 6mph per decade. At the same time sea surface and sub surface temperatures in the region increase by upto 1.1°C, providing the additional energy for hurricanes to intensify.The study, published in Samantha Hallam, the lead author of this paper from the University of Southampton and the National Oceanography Centre (NOC), said , "The approach we used could provide a better way to predict Bermuda storm intensity than current theory or operational methods alone. It could also be use elsewhere in the subtropical Atlantic where there is a shallow mixed layer depth, typically north of twenty five degrees north."We used hurricane potential intensity theory, locally-based weather balloon soundings, surface and upper ocean observations of conditions in and around hurricanes passing within 100km of Bermuda over the last 65 years (including direct hits and 'near-miss' storms)."Mark Guishard, co-author and Director of the Bermuda Weather Service said "the research demonstrates the greater relevance of upper ocean heat versus sea surface temperatures alone in the prediction of hurricane intensity. Preliminary testing with the recent passage of Hurricane Paulette shows promising results that this technique could be further developed into an additional operational tool for forecasters locally."These findings are the result of a statistical analysis on hurricane paths within 100km of Bermuda, between 1955 and 2019. The research used surface and subsurface ocean temperature observations from the Bermuda Atlantic Times Series (BATS) Hydrostation S programme, managed by the Bermuda Institute of Ocean Sciences.This research was funded by the Natural Environmental Research Council (NERC) and Bermuda Institute of Ocean Sciences, and involved a collaboration between the University of Southampton, the National Oceanography Centre, the Bermuda Institute of Ocean Sciences and the Met Office. | Climate | 2,021 |
February 11, 2021 | https://www.sciencedaily.com/releases/2021/02/210211144307.htm | Small mammals climb higher to flee warming temperatures in the Rockies | The golden-mantled ground squirrel (Callospermophilus lateralis) is a popular sight among tourists in the Rocky Mountains -- the small rodent is a photogenic creature with a striped back and pudgy cheeks that store seeds and other food. | But there's a reality that Instagram photos don't capture, said Christy McCain, an ecologist at the University of Colorado Boulder. In a new study spanning nearly 13 years, she and her colleagues discovered that the ground squirrel has joined many other small mammals in Colorado's Rocky Mountains that are making an ominous trek: They're climbing uphill to avoid warming temperatures in the state brought on by climate change."It's frightening," said McCain, an associate professor in the Department of Ecology and Evolutionary Biology. "We've been talking about climate change in the Rockies for a long time, but I think we can say that this is a sign that things are now responding and responding quite drastically."The golden-mantled ground squirrel, which is often confused for a chipmunk, lives in conifer forests in the Rockies and several other western mountain ranges."It is likely one of the most photographed mammals in Rocky Mountain National Park as it poses and preens on rocks near the roadside and in campgrounds," said McCain, also curator of vertebrates at the CU Museum of Natural History. "They hibernate in winter, are territorial in the summer, and they make distinctive alarm calls to notify each other of nearby dangers."Her latest research, published this week in the journal The team reports that, on average, the ranges of these critters seem to have shifted by more than 400 feet up in elevation since the 1980s. Montane mammals, or those already living at higher elevations like the ground squirrel, have taken the biggest brunt -- moving up by 1,100 feet on average. It's a significant change that, if it continues, could wind up squeezing many of these animals out of Colorado entirely.And while many of these small creatures won't ever show up on Colorado postcards, McCain said that they may be bellwethers for larger and increasingly urgent changes in the Rocky Mountains.For McCain, the project is, in many ways, a culmination of her lifelong love of mountains.It began in the mid-1990s when she was serving in the Peace Corps in Honduras. There, McCain was taken by how much the tropical nation's mountains resembled layer cakes: As she climbed up in elevation, mountain ecosystems transformed around her, sometimes dramatically."Every place you went to, there were completely different birds," she said. "The changes are so stark."But that layer cake nature may also be the downfall of mountain ecosystems in the face of climate change. Colorado has warmed by nearly 3.5 degrees Fahrenheit since the 1980s because of human-caused climate change. As the state heats up, many scientists have predicted that ponderosa pine forests and other mountain ecosystems will have to move higher to find cooler weather. Some animals, and even entire communities, may be pushed to the tops of mountains with nowhere else to go.McCain and her colleagues wanted to find out if that upward shift was already happening in the Rockies.Beginning in 2008, her team visited multiple sites in Colorado's Front Range and San Juan mountains to collect records of the current ranges of 47 species of rodents and shrews. They included rare animals, such as the pygmy shrew (Sorex hoyi), which weighs less than a quarter and ranks as North America's smallest mammal. The endangered Preble's jumping mouse (Zapus hudsonius preblei), known for its long tail and big feet that are useful for swimming, also made the list. In some cases, McCain said, the habitats were so remote that the researchers traveled using horse trains to carry their equipment."We had to get used to really unpleasant conditions," McCain said. "We put up with being wet in the mountains and being hot in the desert, flash floods and lightning storms."The group then compared the findings from their surveys to roughly 4,500 historic records from museum collections in the Front Range and San Juan mountains dating back to the 1880s. They included animals stored in CU Boulder's own museum, which houses nearly 12,000 mammal specimens from Colorado.The results showed a complex response to climate change and other pressures. Some of the animals in the survey, McCain said, moved down in elevation, not up, while others actually saw their ranges increase since the 1980s.But most of the study mammals shifted uphill -- and not by a small amount. That was especially true for those already living at high elevations. Before 1980, the pygmy shrew, for example, was never detected above 9,800 feet in elevation. Today, its maximum extent is more than 11,800 feet. The golden-mantled ground squirrel similarly hiked up by 650 feet, or 200 meters, in the Front Range and 2,300 feet, or 700 meters, in the San Juans."I was expecting that we would see something between 100 to 200 meters, but we saw a lot more," McCain said. "This is way bigger than the change that has been determined in other mountain regions around the world."The study, McCain said, paints a stark picture of a mountain range in crisis. But it's one with a silver lining: There may still be time to protect the West's iconic ponderosa pine forests, alpine meadows and scraggly tundra -- but only if Coloradans and people around the world act now to reduce their greenhouse gas emissions."It's a wake-up call," McCain said. "We have to start taking this seriously immediately if we want to have healthy mountains and ecosystems."Other coauthors on the new study include Tim Szewczyk, a former graduate student at CU Boulder now at the University of Lausanne, and Sarah King of Colorado State University. | Climate | 2,021 |
February 11, 2021 | https://www.sciencedaily.com/releases/2021/02/210211144255.htm | New insights to past ecosystems are now available based on pollen and plant traits | Researchers have mined and combined information from two databases to link pollen and key plant traits to generate confidence in the ability to reconstruct past ecosystem services. | The approach provides a new tool to that can be used to understand how plants performed different benefits useful for humans over the past 21,000 years, and how these services responded to human and climate disturbances, including droughts and fires, said Thomas Brussel, a postdoctoral researcher in the University of Oregon's Department of Geography.The approach is detailed in a paper published online Jan. 13 in the journal Ultimately, Brussel said, the combined information could enhance decisions about conservation to allow regional ecosystem managers to continue to provide goods and services, such as having plants that protect hillsides from erosion or help purify water, based on their relationship with climate changes in the past.For example, he said, an ecosystem's history may indicate that plants have previously withstood similar disruptions and could continue to thrive through preservation techniques.Pollen cores have long helped scientists study environmental and ecological changes in a given location that have occurred because of climate changes and wildfires over recent geologic time. Combining pollen records to plant traits provides a picture of how well ecosystems have functioned under different scenarios, Brussel said."The biggest finding in this study is that researchers can now be confident that transforming pollen into the processes that ecosystems undergo works," he said. "With this information, we can now explore new questions that were previously unanswerable and provide positive guidance on how we can conserve and manage landscapes and biodiversity."Brussel began pursuing the approach as a doctoral student at the University of Utah in the emerging field of functional paleoecology. Initial reception to the approach, when presented at conferences, drew interest but also calls for proof that the idea is possible, Brussel said. The paper, co-authored with his Utah mentor Simon Christopher Brewer, provides a proof-of-concept that his approach works.For the study, Brussel and Brewer merged publicly available records for surface pollen samples found in the Neotoma Paleoecology Database and plant traits, specifically leaf area, plant height and seed mass, from the Botanical Information and Ecology Network.They then restricted their results to only plants native to ecosystems from Mexico to Canada by combing through the U.S. Department of Agriculture's PLANTS Database and a compilation of all native plants in Mexico.The resulting data for North America covers some 1,300 individual sites and includes 9.5 million plant height measurements for 2,146 species, 13,103 leaf area details from 1,016 species, and 16,621 seed mass data from 3,580 species.The information, Brussel said, provides extensive details on the fitness of ecosystems that should help researchers study the mechanisms of changes in carbon or water cycling related to climate change."Our work is extremely relevant to modern climate change," he said. "The past houses all these natural experiments. The data are there. We can use that data as parallels for what may happen in the future. Using trait-based information through this approach, we can gain new insight, with confidence, that we haven't been able to get at before now."At the UO, Brussel is working with Melissa Lucash, a research assistant professor who studies large, forested landscapes with a focus on the impacts of climate change and wildfires. Brussel is part of Lucash's research on potential climate changes being faced by Siberia's boreal forests and tundra.He also is applying his approach to potential conservation and management strategies for some of the world's biodiversity hotspots, which are seeing a decline in plant species and wildlife as a result of global change."Using the newly validated approach, my idea is to assess the severity of the biodiversity degradation that has been occurring in these regions over recent millennia," Brussel said. "My end goal is to create a list of regions that can be prioritized for hotspot conservation, based on how severe an ecosystem's services have declined over time." | Climate | 2,021 |
February 11, 2021 | https://www.sciencedaily.com/releases/2021/02/210211113920.htm | Protected areas see continued deforestation but at a reduced rate, OSU research shows | A survey of more than 18,000 land parcels spanning 2 million square miles across 63 countries shows that a "protected area" designation reduces the rate of deforestation but does not prevent it. | Published today in The findings are also timely given President Biden's recent executive order on climate change, which calls for protecting 30% of the United States' land and waters, up from the current 12%, and developing "a plan for promoting the protection of the Amazon rainforest and other critical ecosystems that serve as global carbon sinks.""Evidence indicates that we're in the middle of a mass extinction event the likes of which the planet has seen only five times before," said study leader Christopher Wolf, a postdoctoral researcher in the Oregon State University College of Forestry. "Formally protected areas have been proposed as a primary tool for reducing deforestation, and therefore stemming species extinctions and slowing reductions in carbon storage."In research believed to be the first comprehensive look at how effective protected areas are at limiting forest loss, Wolf and collaborators used the World Database on Protected Areas and forest change maps to estimate rates of change within protected areas. The rates were then compared to those of control areas with similar characteristics such as elevation, slope and proximity to densely populated areas.They found protected areas' deforestation rate is 41% lower than that of unprotected areas. They also found that earlier estimates suggesting 15.7% of the Earth's forest were protected from deforestation were much too optimistic."It's clearly not enough just to call a forest area 'protected' and assume that it really is," Wolf said. "When you look at conservation effectiveness, you can't simply rely on the amount of officially protected land as a metric. Nearly one-third of all protected areas are actually under intense human pressure."Protected area deforestation rates were highest in Africa, Europe and South America and lowest in Oceania -- Australia, New Zealand, Papua New Guinea and nearby island chains.Among the 63 nations studied, 34 have at least 17% of their forest area protected -- i.e., are in line with the target percentage established by the Convention on Biological Diversity.New Zealand ranked No. 1 in percentage of area protected when effectiveness was factored in, and China ranked last. South Africa's protected areas were the most effective, with deforestation rates eight times lower than those of control sites. Sierra Leone, Malaysia and Cambodia were the three nations losing their forest cover the fastest."Protected area effectiveness is limited by varying levels of monitoring and enforcement and the money available for them," Wolf said. "Unfortunately, our research shows that protected areas rarely if ever do more than slow down deforestation. And in general, the larger the protected area, the higher the rate of forest loss."That has important implications for the 17% target set by the Convention on Biological Diversity, says co-author Matt Betts, director of the Forest Biodiversity Research Network in OSU's Department of Forest Ecosystems and Society."If you take into account imperfect protected areas' effectiveness, it could require a near doubling of this original target," he said. | Climate | 2,021 |
February 10, 2021 | https://www.sciencedaily.com/releases/2021/02/210210142155.htm | Flooding in the Columbia River basin expected to increase under climate change | The Columbia River basin will see an increase in flooding over the next 50 years as a result of climate change, new modeling from Oregon State University indicates. | The magnitude of flooding -- the term used to describe flooding severity -- is expected to increase throughout the basin, which includes the Columbia, Willamette and Snake rivers and hundreds of tributaries. In some areas, the flooding season will expand, as well."The flood you're used to seeing out your window once every 10 years will likely be larger than it has been in the past," said the study's lead author, Laura Queen, a research assistant at OSU's Oregon Climate Change Research Institute.The findings are based on natural river conditions and do not take into account potential flood control measures, including dams, but the increases are significant nonetheless, said study co-author Philip Mote, a professor in the College of Earth, Ocean, and Atmospheric Sciences and dean of the Graduate School at OSU."We don't know how much of this increased flood risk can be managed through mitigation measures until we study the issue further," Mote said. "But managing a 30% to 40% increase, as is predicted for many areas, is clearly beyond our management capabilities."The findings were published recently in the journal The study emerged out of Queen's work on her honors thesis as an undergraduate in the University of Oregon's Robert D. Clark Honors College. Queen, a Corvallis native, continued the work at OCCRI and is now enrolled in a doctoral program at Victoria University of Wellington in New Zealand.The goal of Queen's research was to better understand how flooding in the Columbia River basin might change as the planet warms. The Columbia River drains much of the Pacific Northwest, including portions of seven states and British Columbia. It has the fourth-largest streamflow volume in the United States.The Pacific Northwest has a history of costly and disruptive flooding. The largest flood in modern history occurred in late spring 1948 when flooding from the Columbia River destroyed the city of Vanport, Oregon, displacing more than 18,500 people. Floods on the Chehalis River in 2007 and 2009 closed Interstate 5 in Washington and floods along the Willamette River in 1996 and 2019 caused hundreds of millions of dollars in damage.Queen ran simulations using hydrology models and a previously collected set of streamflow data for 396 sites throughout the Columbia River basin and other watersheds in western Washington. The data included a 50-year window from the past, 1950-1999, as well as a 50-year window of expected streamflows in the future, 2050 to 2099, that was developed using several different climate models.Previous studies predicting future streamflows showed mixed results, but the results of this new analysis were clear and surprising, Mote said."This was the best and most complete set of data," he said. "It shows that the magnitude of one-, 10- and 100-year floods is likely go up nearly everywhere in the region. These are profound shifts."The Willamette River and its tributaries are expected to see the biggest increase in flooding magnitude, with 50% to 60% increases in 100-year floods. The streamflows are expected to be smaller downstream and grow larger upstream.On the Snake River, streamflows will grow larger as they move downstream until they reach the confluence of the Salmon River tributary and then will drop abruptly. Parts of the Snake River will see a 40% increase in 10-year floods and a 60% increase in 100-year floods. But below the confluence with the Salmon River on the Oregon-Idaho border, the increase drops to 20% for 10-year floods and 30% for 100-year floods.The model also suggests a significant increase in the flood season on the Snake River, which is largely concentrated in late spring now but could start as early as December or January in the future, Mote said.One of the drivers of the change is warmer winters that will see precipitation fall more as rain instead of snow. Lower spring snowpack will lead to earlier spring streamflows in many rivers. The cold upper Columbia River basin in Canada is projected to experience little change in snowpack volume, but the snow will melt faster.The study's findings could have implications for flood management policy in the coming decades, Mote said. A logical next step in the research is to run the models again and include existing dams to see the role they may play in mitigating flooding."This work provides information and impetus for the people who manage flood risk," he said. "We'll need to know how much of this can be mitigated by existing flood control." | Climate | 2,021 |
February 10, 2021 | https://www.sciencedaily.com/releases/2021/02/210210133335.htm | Rapid ice retreat during last deglaciation parallels current melt rates | Ten thousand square kilometres of ice disappeared in a blink of an eye from an ice sheet in the Storfjorden Trough offshore Svalbard, a new study shows. This dramatic break off was preceded by quite a rapid melt of 2.5 kilometres of ice a year. This parallels the current melt rates in Antarctica and Greenland and worries the scientists behind the study. | "Our measurements of the ice retreat in Storfjorden Trough show that the prevailing conditions to the great break off, match what we see in Antarctica and Greenland today. It is uncanny. There are new studies published almost weekly, that show that the retreat of current ice sheets is two to four km a year and that it's speeding up." Says CAGE-professor and first author Tine Lander Rasmussen.The last deglaciation, 20,000 to 10,000 years ago, was a period of coexisting global warming and rapidly shrinking ice sheets. But stating the actual correlation between the two is not as simple as it sounds. The period in question was climatically unstable, and big melts were interrupted by re-freezing and formation of new ice. The speed of the ice retreat, relative to climatic changes, has therefore been difficult to establish."We have studied the ice sheet development 20,000 - 10,000 years ago using marine sediment cores. The 12 cores have been collected in the area during the past 18 years, and meticulously analysed for different types of microfossils of single-celled organisms called foraminifera," says Rasmussen.The biochemistry in the foraminifera fossils helps reconstruct the enormous amount of information about the state of the environment in prehistoric times. The sediments were sliced up in slices representing time periods of 30 to 70 years. Over 70 samples were dated and analyzed."What we saw is that the ice sheet starts retreating some 20,000 years ago but lingers on a ridge in the fjord. Then, some 15,000 years ago the atmosphere and ocean temperatures warm up, impacting the ocean circulation. A huge chunk of the ice sheet disappears at the same time. At the start of the Holocene warm period, 11,000 years ago, things really pick up speed. We can't see any more evidence of an ice sheet covering the ocean floor after that time."The periods of extremely rapid ice sheet retreats are consistently correlating with periods of global warming of oceans and temperature. This is mirrored in ice sheet retreat from other eight Northern Norwegian fjord systems."This is strengthening our hypothesis that an increase in ocean temperature and global warming is the direct cause of the chain of the events leading up to the dramatically rapid ice sheet disintegration." Says Rasmussen.This gives some alarming perspectives on present-day outlook. The great melt of the glacial maximum to the Holocene was 10,000 years in the making. The present climate change is much more rapid."The final retreat of the Storfjorden Trough ice sheet happened as rapidly in the outer parts as it did further up the trough. This means that as soon as warmer oceanic water got access to the ice sheet, it surged pretty rapidly inward from the edge of the ice shelf. To the interior of the sheet itself. We see this happening in Antarctica today. The Larsen A (1995), B (2003) and C (2017) break-offs are examples of this process." | Climate | 2,021 |
February 10, 2021 | https://www.sciencedaily.com/releases/2021/02/210210133418.htm | Study on submarine permafrost suggests locked greenhouse gases are emerging | Something lurks beneath the Arctic Ocean. While it's not a monster, it has largely remained a mystery. | According to 25 international researchers who collaborated on a first-of-its-kind study, frozen land beneath rising sea levels currently traps 60 billion tons of methane and 560 billion tons of organic carbon. Little is known about the frozen sediment and soil -- called submarine permafrost -- even as it slowly thaws and releases methane and carbon that could have significant impacts on climate.To put into perspective the amount of greenhouse gases in submarine permafrost, humans have released about 500 billion tons of carbon into the atmosphere since the Industrial Revolution, said Sandia National Laboratories geosciences engineer Jennifer Frederick, one of the authors on the study published in IOP Publishing journal While researchers predict that submarine permafrost is not a ticking time bomb and could take hundreds of years to emit its greenhouse gases, Frederick said submarine permafrost carbon stock represents a potential giant ecosystem feedback to climate change not yet included in climate projections and agreements."It's expected to be released over a long period of time, but it's still a significant amount," she said. "This expert assessment is bringing to light that we can't just ignore it because it's underwater, and we can't see it. It's lurking there, and it's a potentially large source of carbon, particularly methane."The team of researchers led by Brigham Young University graduate student Sara Sayedi and senior researcher Ben Abbott compiled available articles and reports on the subject to create a base analysis of submarine permafrost's potential to affect climate change. The study was coordinated through the Permafrost Carbon Network, which has more than 400 members from 130 research institutions in 21 countries.The study was conducted through an expert assessment that sought answers to several central questions: What is the current extent of submarine permafrost? How much carbon is locked in submarine permafrost? How much has been and will be released? What is the rate of release into the atmosphere?The participating experts answered questions using their scientific skills, which could include modeling, data analysis or literature synthesis. Frederick, one of the original advocates of the study, has been modeling submarine permafrost for almost 10 years and answered the questions through the lens of her research, which is primarily in numerical modeling. She said she uses published material for model inputs or works directly with researchers who visit the Arctic and provide datasets.Her work on the study was funded by the Laboratory Directed Research and Development program that enables Sandia scientists and engineers to explore innovative solutions to national security issues.Frederick's work aligned with Sandia's Arctic Science and Security Initiative. For more than 20 years, the Labs have had a presence in northern Alaska, said Sandia atmospheric sciences manager Lori Parrott.Working for the Department of Energy Office of Biological and Environmental Research, Sandia manages the Atmospheric Radiation Measurement user facility that collects atmospheric data continuously. Researchers measure and predict the speed of de-icing at the North Slope to help federal leaders make decisions on climate change and national security. In addition, Sandia creates accurate models for both sea and land ice and develops technologies for greenhouse gas monitoring. With more than 20 years of data, researchers can begin to decipher trends, Parrott said."I hope this study begins to unite the research community in submarine permafrost," said Frederick. "Historically, it's not only been a challenging location to do field work and make observations, but language barriers and other obstacles in accessibility to the existing observations and literature has challenged international scientific progress in this area."The team estimates that submarine permafrost has been thawing since the end of the last glacial period 14,000 years ago, and currently releases about 140 million tons of carbon dioxide and 5.3 million tons of methane into the atmosphere each year. This represents a small fraction of total human-caused greenhouse gas emissions per year, about the same yearly footprint as Spain, Sayedi said.However, modern greenhouse gas releases are predominantly a result of the natural response to deglaciation, according to the study. Expert estimates from this study suggest human-caused global warming may accelerate greenhouse gas release, but due to lack of research and uncertainties in this area, determining causes and rates of the release will remain unknown until better empirical and modeling estimates are available."I'm optimistic that this study will shed light on the fact that submarine permafrost exists, and that people are studying its role in climate," Frederick said. "The size of the research community doesn't necessarily reflect its importance in the climate system."Almost every expert involved in the study mentioned the permafrost knowledge gap, which makes it harder for scientists to anticipate changes and reduces the reliability of estimates of carbon pools and fluxes, as well as the thermal and hydrological conditions of permafrost. Frederick said that while there is a wealth of ongoing research on terrestrial permafrost, submarine permafrost hasn't been taken on like this before, and hasn't been the subject of nearly as much international collaboration.The amount of carbon sequestered or associated with submarine permafrost is relevant when compared to the numbers of carbon in terrestrial permafrost and what's in the atmosphere today, Frederick said."This is an example of a very large source of carbon that hasn't been considered in climate predictions or agreements," she said. "While it's not a ticking time bomb, what is certain is that submarine permafrost carbon stocks cannot continue to be ignored, and we need to know more about how they will affect the Earth's future." | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209204133.htm | You don't need to know nature to love it | A common belief in nature conservation is that people need to "know nature" in order to care about it. However, new research has found that farmers in the Brazilian Amazon can develop strong connections with nature despite having little knowledge of local biodiversity -- in this case local bird species. | The study, led by researchers at UK and Brazilian institutions, and published in the journal The majority of farmers expressed views that indicated a strong connection with nature, despite recognising fewer than half of the species in the survey. The research, which involved interviews with 227 farmers, found that knowledge of birds and nature connection were not correlated, and they did not have any predictors in common.Many farmers recognised bird species that have adapted to farmland and are widespread in Brazil, but most struggled to identify birds that only live in the Amazon forest.The study is the first of its kind to be carried out in the "Global South" and is significant because previous, similar studies in the US and Europe indicated that knowledge of biodiversity enhances connection with nature.The Amazon rainforest is under threat from deforestation and climate change, and its farm-forest frontiers are suffering from intense habitat and biodiversity loss. Therefore, understanding the feelings and motivations of its farmers is vital as studies have shown that farmers who care strongly about nature are more likely to engage in conservation.Dr Katarzyna Mikolajczak, Postdoctoral Research Fellow at Anglia Ruskin University (ARU) and lead author of the study, said: "Farmers' decisions are critical for the survival of the Amazon and the species that live there, but their environmental motivations are rarely studied. We investigated how a form of the farmers' ecological knowledge -- the ability to recognise local bird species -- related to their sense of attachment and caring about nature, known as nature connection."We found that farmers do not need intimate knowledge of local biodiversity to care about nature. However, at the same time, farmers might have difficulty protecting species without some knowledge -- many of the farmers struggled to identify birds commonly found in the Amazon, so may fail to realise the value of forests as an irreplaceable habitat for many species."Our results contrast with previous similar studies that have taken place in industrialised nations in the Global North, namely the UK and the US, that found a positive correlation between knowing and caring about nature."This suggests that the relationship between ecological knowledge and nature connection is complex and might be context-specific, and we shouldn't assume there is a 'one-size-fits-all' approach to encouraging nature conservation. Our findings indicate that having a knowledge of nature is not necessary in order to connect with nature."The study, which involved academics from Anglia Ruskin University (ARU), Lancaster University and the Federal University of Para in Belem, Brazil, is published in the journal | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209151912.htm | Relaxed precautions, not climate, the biggest factor driving wintertime COVID-19 outbreaks | Wintertime outbreaks of COVID-19 have been largely driven by whether people adhere to control measures such as mask wearing and social distancing, according to a study published Feb. 8 in | The researchers -- working in summer 2020 -- ran simulations of a wintertime coronavirus outbreak in New York City to identify key factors that would allow the virus to proliferate. They found that relaxing control measures in the summer months led to an outbreak in the winter regardless of climate factors."Our results implied that lax control measures -- and likely fatigue with complying with control measures -- would fuel wintertime outbreaks," said first author Rachel Baker, an associate research scholar in Princeton's High Meadows Environmental Institute (HMEI). Baker and her co-authors are all affiliated with the HMEI Climate Change and Infectious Disease initiative."Although we have witnessed a substantial number of COVID-19 cases, population-level immunity remains low in many locations," Baker said. "This means that if you roll back enforcement or adherence to control measures, you can still expect a large outbreak. Climate factors including winter weather play a secondary role and certainly don't help."The researchers found that even maintaining rigid control measures through the summer can lead to a wintertime outbreak if climate factors provided enough of a boost to viral transmission. "If summertime controls are holding the transmissibility of coronavirus at a level that only just mitigates an outbreak, then winter climate conditions can push you over the edge," Baker said. "Nonetheless, having effective control measures in place last summer could have limited the winter outbreaks we're now experiencing."Cases have climbed in many northern hemisphere locations since November. In the United States, spikes in COVID-19 cases are thought to be tied to increased travel and gatherings for Thanksgiving and Christmas. Notably, outbreaks were recorded in temperate locations such as Los Angeles in addition to regions with much colder conditions, Baker said. At the same time, large outbreaks were observed in South Africa from November to January, which are that country's summer months."The greater incidence of COVID-19 in various environs really speaks to the climate's limited role at this stage," Baker said.In May, the same authors published a paper in the journal Science suggesting that local climate variations would be unlikely to affect the coronavirus pandemic. The paper suggested that hopes that the warmer conditions of summer would slow the transmission of the novel coronavirus, SARS-CoV-2, in the northern hemisphere were unrealistic.Gabriel Vecchi, a professor of geosciences and the High Meadows Environmental Institute and co-author of both studies, said that the virus currently spreads too quickly and that people are too susceptible for climate to be a determining factor."The influence of climate and weather on infection rates should become more evident -- and thus a potentially useful source of information for disease prediction -- as growing immunity moves the disease into endemic phases from the present epidemic stage," Vecchi said.The most recent study provides insight on how scientists can determine the impact of various factors on the virus at various times, said co-author C. Jessica Metcalf, associate professor of ecology and evolutionary biology and public affairs and an HMEI associated faculty member."An important challenge that we tackle here is balancing the role of many potential factors on the trajectory of the epidemic," Metcalf said. "As the pandemic progresses, both natural and vaccinal immunity will play an increasing role, underscoring the importance of developing a handle on the landscape of immunity."Critical factors to consider when projecting the future of COVID-19 are emerging variants of the virus, as well as how efforts to contain coronavirus have changed other diseases, said co-author Bryan Grenfell, the Kathryn Briger and Sarah Fenton Professor of Ecology and Evolutionary Biology and Public Affairs and associated faculty in HMEI.In November, Grenfell and his co-authors in the Climate Change and Infectious Disease initiative published a paper in the Proceedings of the National Academy of Sciences that non-pharmaceutical interventions (NPIs) such as mask wearing and social distancing could result in large, delayed outbreaks of endemic diseases such as influenza and respiratory syncytial virus (RSV)."The interaction between NPIs and immunity will become even more complex as a variety of vaccines are deployed and new viral variants arise," Grenfell said. "Understanding the impact of these variables underlines the importance of immune surveillance and greatly expanded viral sequencing."Additional authors of the current paper include Wenchang Yang, an associate research scholar in geosciences at Princeton.The paper, "Assessing the influence of climate on wintertime SARS-CoV-2 outbreaks" was published online Feb. 8 by | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209151842.htm | Poorer mental health smolders after deadly, devastating wildfire | In 2018, a faulty electric transmission line ignited the Camp Fire in Northern California, ultimately consuming 239 square miles and several communities, including the town of Paradise, which was 95 percent destroyed. At least 85 people died. | Structures have been rebuilt, but some things are worse. In a paper published February 2, 2021 in the Direct exposure to large-scale fires significantly increased the risk for mental health disorders, particularly post-traumatic stress disorder (PTSD) and depression, the scientists wrote."We looked for symptoms of these particular disorders because emotionally traumatic events in one's lifetime are known to trigger them," said senior author Jyoti Mishra, PhD, professor in the Department of Psychiatry at UC San Diego School of Medicine and co-director of the Neural Engineering and Translation Labs at UC San Diego. Pre-existing childhood trauma or sleep disturbances were found to exacerbate mental health problems, but factors like personal resilience and mindfulness appeared to reduce them."We show climate change as a chronic mental health stressor. It is not like the pandemic, in that it is here for a period of time and can be mitigated with vaccines and other measures. Climate change is our future, and we need immediate action to slow down the changes being wreaked upon the planet, and on our own wellbeing."Mishra, with collaborators at California State University, Chico and University of South Carolina, conducted a variety of mental health assessments on residents who had been exposed to the Camp Fire six months after the wildfire and those much farther away. Roughly two-thirds of those tested were residents who lived in or around Chico, a Northern California city located approximately 10 to 15 miles of the center of the Camp Fire. The remaining third were San Diego residents living approximately 600 miles from the wildfire and presumably unimpacted.The researchers found that the Northern California residents experienced measurable increases in PTSD, depression and anxiety disorders, which were worsened by proximity and exposure to the Camp Fire or by previous adverse experiences involving childhood trauma, such as abuse and neglect.Chronic mental health problems fanned by the wild fire were ameliorated, however, by physical exercise, mindfulness and emotional support, all of which may contribute to personal resilience and the ability to bounce back after stressful life events.The worrisome thing is that stressful life events like the Camp Fire are becoming more frequent, due to climate change, said study co-author Veerabhadaran Ramanathan, PhD, Distinguished Professor of Atmospheric and Climate Sciences at Scripps Institution of Oceanography at UC San Diego."Since the 1970s, fire extent in California has increased by 400 percent," said Ramanathan. "While a faulty transmission line may have lit the Camp Fire in 2018, it is part of an overall disastrous multi-decadal trend fueled by human-caused climate warming. Through evaporative drying of the air, the soil and the trees, warming acts as a force multiplier. By 2030, the warming is likely to amplify by 50 percent. This surprising, if not shocking, study identifies mental illness as a grave risk for the coming decades."Not just in California, but the world, write the authors."Unchecked climate change projected for the latter half of this century may severely impact the mental wellbeing of the global population. We must find ways to foster individual resiliency," wrote the study authors.Co-authors include: Saria Silveira and Gillian Grennan, UC San Diego; Mariah Kornbluh, University of South Carolina; and Mathew C. Withers, California State University, Chico. | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209151816.htm | Shining a light on the true value of solar power | Beyond the environmental benefits and lower electric bills, it turns out installing solar panels on your house actually benefits your whole community. Value estimations for grid-tied photovoltaic systems prove solar panels are beneficial for utility companies and consumers alike. | For years some utility companies have worried that solar panels drive up electric costs for people without panels. Joshua Pearce, Richard Witte Endowed Professor of Materials Science and Engineering and professor of electrical and computer engineering at Michigan Technological University, has shown the opposite is true -- grid-tied solar photovoltaic (PV) owners are actually subsidizing their non-PV neighbors.Most PV systems are grid-tied and convert sunlight directly into electricity that is either used on-site or fed back into the grid. At night or on cloudy days, PV-owning customers use grid-sourced electricity so no batteries are needed."Anyone who puts up solar is being a great citizen for their neighbors and for their local utility," Pearce said, noting that when someone puts up grid-tied solar panels, they are essentially investing in the grid itself. "Customers with solar distributed generation are making it so utility companies don't have to make as many infrastructure investments, while at the same time solar shaves down peak demands when electricity is the most expensive."Pearce and Koami Soulemane Hayibo, graduate student in the Michigan Tech Open Sustainability Technology (MOST) Lab, found that grid-tied PV-owning utility customers are undercompensated in most of the U.S., as the "value of solar" eclipses both the net metering and two-tiered rates that utilities pay for solar electricity. Their results are published online now and will be printed in the March issue of The value of solar is becoming the preferred method for evaluating the economics of grid-tied PV systems. Yet value of solar calculations are challenging and there is widespread disagreement in the literature on the methods and data needed. To overcome these limitations, Pearce and Hayibo's paper reviews past studies to develop a generalized model that considers realistic costs and liabilities utility companies can avoid when individual people install grid-tied solar panels. Each component of the value has a sensitivity analysis run on the core variables and these sensitivities are applied for the total value of solar.The overall value of solar equation has numerous components:Pearce said one of the paper's goals was to provide the equations to determine the value of solar so individual utility companies can plug in their proprietary data to quickly make a complete valuation."It can be concluded that substantial future regulatory reform is needed to ensure that grid-tied solar PV owners are not unjustly subsidizing U.S. electric utilities," Pearce explains. "This study provides greater clarity to decision makers so they see solar PV is truly an economic benefit in the best interest of all utility customers."Solar PV technology is now a profitable method to decarbonize the grid, but if catastrophic climate change is to be avoided, emissions from transportation and heating must also decarbonize, Pearce argues.One approach to renewable heating is leveraging improvements in PV with heat pumps (HPs), and it turns out investing in PV+HP tech has a better rate of return than CDs or savings accounts.To determine the potential for PV+HP systems in Michigan's Upper Peninsula, Pearce performed numerical simulations and economic analysis using the same loads and climate, but with local electricity and natural gas rates for Sault Ste. Marie, in both Canada and U.S. North American residents can profitably install residential PV+HP systems, earning up to 1.9% return in the U.S. and 2.7% in Canada, to provide for all of their electric and heating needs."Our results suggest northern homeowners have a clear and simple method to reduce their greenhouse gas emissions by making an investment that offers a higher internal rate of return than savings accounts, CDs and global investment certificates in both the U.S. and Canada," Pearce said. "Residential PV and solar-powered heat pumps can be considered 25-year investments in financial security and environmental sustainability." | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209113848.htm | High greenhouse gas emissions from Siberian Inland Waters | Rivers and lakes at high latitudes are considered to be major sources for greenhouse gas emissions to the atmosphere, but these losses are poorly constrained. In a study published in | High latitude regions play a key role in the global carbon cycle and climate system. An important question is the degree of mobilization and atmospheric release of vast soil carbon stocks, partly stored in permafrost, with amplified warming of these regions. A fraction of this carbon is exported to inland waters and emitted to the atmosphere, yet these losses are poorly constrained and seldom accounted for in assessments of high latitude carbon balances. This is particularly relevant for Western Siberia, with its extensive peatland carbon stocks that are expected to be affected by climate warming.Now researchers at the Climate Impacts Research Centre (CIRC), Umeå University, and collaborators from Russia and France have quantified the carbon emission from inland waters of Western Siberia. Due to the remoteness and large area (3.6 million km"We collected data of representative lakes and rivers over 2,000 km distance, including the main channel of Arctic's largest watershed the Ob' River," explains lead author Jan Karlsson.Based on these data and information on the distribution of inland waters of the region the research team show high carbon emission from Western Siberian inland waters and that these systems play an important role in the continental carbon cycle."Our results emphasize the important role of carbon emissions from inland waters in the regional carbon cycle. The carbon emission from the inland waters was almost an order of magnitude higher that carbon export to the Arctic Ocean and reached nearly half of the region's land carbon uptake."The high significance of inland waters in the carbon cycle of Western Siberia is likely a result of the overall flat terrain, which lead to relatively high water coverage and long water transit times, and thus favorable conditions for decomposition and outgassing of land derived carbon in inland waters. The authors stress that further studies on the coupled land-water carbon cycle are needed in order to improve the understanding of regional differences in the contemporary carbon cycle and predictions of future conditions in these understudied and climate-sensitive areas."Ignoring carbon outgassing from inland waters will likely largely underestimate the impact of warming on these regions and overlook their weakening capacity to act as terrestrial carbon sinks." | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209113822.htm | Ecological interactions as a driver of evolution | Understanding the interaction of organisms in the evolution of species is an important topic in ecology. Insects and plants, for example, are two large groups on earth that are linked by a variety of interactions. Since the mid-20th century, theories linking this diversity and specific interactions have proliferated. | The development of new technologies and new methods has made it possible to study the interaction between plants and insects in greater detail and to reveal the impact of these interactions on their respective evolution. In a new study, an international team of researchers, including botanist Prof. Stefan Wanke of TU Dresden, has established the link between ecological changes, genome-level adaptations and macroevolutionary consequences, confirming the importance of ecological interactions as drivers of evolution over long periods of time.Butterflies belonging to the family Papilionidae are an exemplary group for this question. These butterflies specialize in the consumption of poisonous plants, with about 30% of the species feeding exclusively on plants in the family Aristolochiaceae.Consumption of such plants gives the caterpillars of these butterflies an advantage, as they secrete the plants' toxins, which in turn make them poisonous. However, the larvae themselves do not suffer any harm from the toxin."We knew before we started this study that certain genes of the cytochrome P450 family in the Papillonidae are partly responsible for the adaptation to plants, especially for the detoxification of toxic compounds. However, many different genes are probably involved overall, because in addition to detoxification, this adaptation requires that the female butterfly is able to recognize its preferred plant, or also that the caterpillars can develop and survive normally in this environment" explains Prof. Wanke. Scientists had long suspected that evolutionary changes in plants must have an influence on many insect genes. From this, the international team first deduced the relationships between different Papilionidae species and reconstructed their host-plant preferences over time. This allowed them to show that Papilionidae feed on plants belonging to the family Aristolochiaceae and, in particular, the pipevine genus Aristolochia.Based on the global distribution of these two groups of insects and plants, it was then possible to estimate the historical biogeography -- the movement in time and space -- of Papilionidae and Aristolochiaceae species. The researchers discovered that both groups originated in the Northern Hemisphere about 55 million years ago and subsequently spread throughout the world.In the case of the Papilionidae, this migration has been accompanied by major changes in host plants since their emergence. The study of Papilionidae species confirmed that various host-plant shifts were generally associated with accelerated species diversification of the butterflies. In other words, more species emerged as a result of host plant change than when the host plant was retained."Despite our knowledge of the role of key genes such as detoxification genes in the resistance against plant defense mechanisms, our results suggest a more global effect of host plant change on the evolution of Papilionidae. The host plant changes are complex and therefore require a number of adaptations, probably affecting different genes not directly related to the detoxification of toxic compounds," Prof. Wanke describes the interactions that still need to be deciphered, especially on the genetic level. | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209113807.htm | Arctic permafrost releases more CO2 than once believed | Rising global temperatures are causing frozen Arctic soil -- permafrost -- in the northern hemisphere to thaw and release CO | Research results from an international team, which includes a researcher from the University of Copenhagen among others, suggests that the newly discovered phenomenon will release even larger quantities of COThe amount of stored carbon that is bound to iron and gets converted to COResearchers have long been aware that microorganisms play a key role in the release of COWhat is new, is that the mineral iron was believed to bind carbon even as permafrost thawed. The new result demonstrates that bacteria incapacitate iron's carbon trapping ability, resulting in the release of vast amounts of CO"What we see is that bacteria simply use iron minerals as a food source. As they feed, the bonds which had trapped carbon are destroyed and it is released into the atmosphere as greenhouse gas," explains Associate Professor Carsten W. Müller of the University of Copenhagen's Department of Geosciences and Natural Resource Management. He elaborates:"Frozen soil has a high oxygen content, which keeps iron minerals stable and allows carbon to bind to them. But as soon as the ice melts and turns to water, oxygen levels drop and the iron becomes unstable. At the same time, the melted ice permits access to bacteria. As a whole, this is what releases stored carbon as COThe study has just been published in Although the researchers have only studied a single bog area in Abisko, northern Sweden, they have compared their results with data from other parts the northern hemisphere and expect their new results to also be valid in other areas of permafrost worldwide."This means that we have a large new source of COEven though carbon stored in permafrost has a major impact on our climate, researchers know very little about the mechanisms that determine whether carbon in soil is converted into greenhouse gases."The majority of climate research in the Arctic focuses on the amount of stored carbon and how sensitive it is to climate change. There is a great deal less of a focus on the deeper mechanisms which trap carbon in soil," says Carsten W. Müller.Researchers remain uncertain about how much extra carbon from soil could potentially be released through this newly discovered mechanism. Closer investigation is needed. | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209083504.htm | Climate change shrinks and shifts juvenile white shark range | New research led by Monterey Bay Aquarium reveals that even the revered white shark cannot escape the impacts of a changing ocean. The study, published in | Researchers conclude the northward range shift demonstrates the young sharks are being subjected to a loss of suitable thermal habitat, meaning water temperatures within their preferred temperature range are becoming harder to find."Nature has many ways to tell us the status quo is being disrupted, but it's up to us to listen," said Monterey Bay Aquarium Chief Scientist Dr. Kyle Van Houtan. "These sharks -- by venturing into territory where they have not historically been found -- are telling us how the ocean is being affected by climate change."Aquarium scientists and their research partners began using electronic tags to learn about juvenile white sharks in southern California two decades ago when they were preparing to display the young white sharks to the public.When the dramatic North Pacific marine heatwave hit the California coast between 2014-2016, these same researchers started to notice uncharacteristic sightings of juvenile white sharks in nearshore, central California waters near Aptos, California. This is farther north than young white sharks have ever been seen before as the animals historically remain in warmer waters in the southern California Current.Water temperature in the Aptos area averages about 55 degrees Fahrenheit (13 degrees Celsius), but temperature extremes have become more common since the heatwave hit, rising as high as 69 degrees Fahrenheit (21 degrees Celsius) in August 2020.Scientists conducted the research by collecting data from tags the Aquarium and its partners deployed on juvenile white sharks beginning in 2002 to see where the animals were spending most of their time.The team analyzed 22 million electronic data records from 14 sharks and then compared these data to 38 years of ocean temperatures to map the cold edge of the animals' thermal preferences, or "niche."The study charts the significant northward shift in the young white sharks' range.Between 1982 and 2013, the northernmost edge of the juveniles' range was located near Santa Barbara (34° N). But after the marine heatwave, their range shifted dramatically north to Bodega Bay (38.5° N). Ever since, the young sharks' range limit has hovered near Monterey (36° N)."After studying juvenile white shark behavior and movements in southern California for the last 16 years, it is very interesting to see this northerly shift in nursery habitat use," said Dr. Chris Lowe, a co-author of the study and director of the Shark Lab at California State University, Long Beach. "I think this is what many biologists have expected to see as the result of climate change and rising ocean temperatures. Frankly, I'll be surprised if we don't see this northerly shift across more species."Because this shift took scientists by surprise, the team turned to novel sources of data such as community science and recreational fishing records to document this northward movement of the population."This study would not have been possible without contributions from our community scientists and treasured Aquarium volunteers," says Dr. Van Houtan. "Eric Mailander, a local firefighter, provided a decade of detailed logbook records of shark sightings, and volunteer Carol Galginaitis transcribed those hand-written data into an electronic database."The researchers say this study reinforces what scientists have been saying for years: animals and the living world are revealing the impacts of climate change."White sharks, otters, kelp, lobsters, corals, redwoods, monarch butterflies -- these are all showing us that climate change is happening right here in our backyard," says Dr. Van Houtan. "It's time for us to take notice and listen to this chorus from nature. We know that greenhouse gas emissions are rapidly disrupting our climate and this is taking hold in many ways. Our study showed one example of juvenile white sharks appearing in Monterey Bay. But let's be clear: The sharks are not the problem. Our emissions are the problem. We need to act on climate change and reduce our reliance on fossil fuels." | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209083500.htm | Limiting warming to 2 degrees Celsius requires emissions reductions 80% above Paris Agreement targets | In 2017, a widely cited study used statistical tools to model how likely the world is to meet the Paris Agreement global temperature targets. The analysis found that on current trends, the planet had only a 5% chance of staying below 2 degrees Celsius warming this century -- the international climate treaty's supposed goal. | Now, the same authors have used their tools to ask: What emissions cuts would actually be required to meet the goal of 2 C warming, considered a threshold for climate stability and climate-related risks such as excessive heat, drought, extreme weather and sea level rise?The University of Washington study finds that emissions reductions about 80% more ambitious than those in the Paris Agreement, or an average of 1.8% drop in emissions per year rather than 1% per year, would be enough to stay within 2 degrees. The results were published Feb. 9 in Nature's open-access journal "A number of people have been saying, particularly in the past few years, that the emissions targets need to be more ambitious," said lead author Adrian Raftery, a UW professor of statistics. "We went beyond that to ask in a more precise way: How much more ambitious do they need to be?"The paper uses the same statistical approach to model the three main drivers of human-produced greenhouse gases: national population, gross domestic product per person and the amount of carbon emitted for each dollar of economic activity, known as carbon intensity. It then uses a statistical model to show the range of likely future outcomes based on data and projections so far.Even with updated methods and five more years of data, now spanning 1960 through 2015, the conclusion remains similar to the previous study: Meeting Paris Agreement targets would give only a 5% probability of staying below 2 degrees Celsius warming.Assuming that climate policies won't target population growth or economic growth, the authors then ask what change in the "carbon intensity" measure would be needed to meet the 2 degrees warming goal.Increasing the overall targets to cut carbon emissions by an average of 1.8% annually, and continuing on that path after the Paris Agreement expires in 2030, would give the planet a 50% chance of staying below 2 degrees warming by 2100."Achieving the Paris Agreement's temperature goals is something we're not on target to do now, but it wouldn't take that much extra to do it," said first author Peiran Liu, who did the research as part of his doctorate at the UW.The paper looks at what this overall plan would mean for different countries' Paris Agreement commitments. Nations set their own Paris Agreement emissions-reductions pledges. The United States pledged a 1% drop in carbon emissions per year until 2026, or slightly more ambitious than the average. China pledged to reduce its carbon intensity, or the carbon emissions per unit of economic activity, by 60% of its 2005 levels by 2030."Globally, the temperature goal requires an 80% boost in the annual rate of emissions decline compared to the Paris Agreement, but if a country has finished most of its promised mitigation measures, then the extra decline required now will be smaller," Liu said.Assuming that each country's share of the work remains unchanged, the U.S. would need to increase its goal by 38% to do its part toward actually achieving the 2 degrees goal. China's more ambitious and fairly successful plan would need only a 7% boost, and the United Kingdom, which has made substantial progress already, would need a 17% increase. On the other hand, countries that had pledged cuts but where emissions have risen, like South Korea and Brazil, would need a bigger boost now to make up for the lost time.The authors also suggest that countries increase their accountability by reviewing progress annually, rather than on the five-year, 10-year or longer timescales included in many existing climate plans."To some extent, the discourse around climate has been: 'We have to completely change our lifestyles and everything,'" Raftery said. "The idea from our work is that actually, what's required is not easy, but it's quantifiable. Reducing global emissions by 1.8% per year is a goal that's not astronomical."From 2011 to 2015, Raftery says, the U.S. did see a drop in emissions, due to efficiencies in industries ranging from lighting to transportation as well as regulation. The pandemic-related economic changes will be short-lived, he predicts, but the creativity and flexibility the pandemic has required may usher in a lasting drop in emissions."If you say, 'Everything's a disaster and we need to radically overhaul society,' there's a feeling of hopelessness," Raftery said. "But if we say, 'We need to reduce emissions by 1.8% a year,' that's a different mindset."This research was funded by the National Institutes of Health. | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209083451.htm | New factor in the carbon cycle of the Southern Ocean identified | The term plankton describes usually very small organisms that drift with the currents in the seas and oceans. Despite their small size, they play an important role for our planet due to their immense quantity. Photosynthesizing plankton, known as phytoplankton, for example, produce half of the oxygen in the atmosphere while binding huge amounts of carbon dioxide (CO | As other nutrients are abundant, scientists have so far assumed that the amount of the available "micronutrient" iron determines how well phytoplankton thrives or not in the Southern Ocean. Researchers from GEOMAR Helmholtz Centre for Ocean Research Kiel and the UK's National Oceanography Center have now published a study in the international journal "This is an important finding for our ability to assess future changes, but also to better understand phytoplankton in the past," says Dr. Thomas J. Browning of GEOMAR, lead author of the study.Earlier research suggests that greater phytoplankton growth in the Southern Ocean was a key contributor to the onset of the ice ages over the past 2.58 million years. More phytoplankton was able to bind more COIndeed, along with iron, manganese is another essential "micronutrient" required by every photosynthetic organism, from algae to oak trees. In most of the ocean, however, enough manganese is available to phytoplankton that it does not limit its growth.Measurements in remote regions of the Southern Ocean, on the other hand, have shown much lower manganese concentrations. During an expedition on the British research vessel RRS JAMES CLARK ROSS through the Drake Passage between Tierra del Fuego and the Antarctic Peninsula in November 2018, Dr. Browning and his team took water samples. While still on board, they used these water samples and the phytoplankton they contained to conduct experiments on which nutrients affect growth and which do not."In doing so, we were able to demonstrate for the first time a manganese limitation for phytoplankton growth in the center of Drake Passage. Closer to shore, iron was the limiting factor, as expected," Dr. Browning reports.After the expedition, the team used additional model calculations to assess the implications of the experimental results. Among other things, they found that manganese limitation may have been even more widespread during the ice ages than it is today. "This would make this previously unaccounted for factor a central part of understanding the ice ages," says Dr. Browning.However, because this is the first record in a specific region of the Southern Ocean, further research is needed to better understand the geographic extent and timing of manganese limitation in the Southern Ocean. "We also still need to study what factors control manganese concentrations in seawater and how phytoplankton adapt to manganese scarcity. All of this is critical to building more accurate models of how the Earth system works," Thomas Browning concludes. | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210208094608.htm | A billion years in 40 seconds: video reveals our dynamic planet | Geoscientists have released a video that for the first time shows the uninterrupted movement of the Earth's tectonic plates over the past billion years. | The international effort provides a scientific framework for understanding planetary habitability and for finding critical metal resources needed for a low-carbon future.It reveals a planet in constant movement as land masses move around the Earth's surface, for instance showing that Antarctica was once at the equator.The video is based on new research published in the March 2021 edition of Co-author and academic leader of the University of Sydney EarthByte geosciences group, Professor Dietmar Müller, said: "Our team has created an entirely new model of Earth evolution over the last billion years."Our planet is unique in the way that it hosts life. But this is only possible because geological processes, like plate tectonics, provide a planetary life-support system."Lead author and creator of the video Dr Andrew Merdith began work on the project while a PhD student with Professor Müller in the School of Geosciences at the University of Sydney. He is now based at the University of Lyon in France.Co-author, Dr Michael Tetley, who also completed his PhD at the University of Sydney, told Euronews: "For the first time a complete model of tectonics has been built, including all the boundaries""On a human timescale, things move in centimetres per year, but as we can see from the animation, the continents have been everywhere in time. A place like Antarctica that we see as a cold, icy inhospitable place today, actually was once quite a nice holiday destination at the equator."Co-author Dr Sabin Zahirovic from the University of Sydney, said: "Planet Earth is incredibly dynamic, with the surface composed of 'plates' that constantly jostle each other in a way unique among the known rocky planets. These plates move at the speed fingernails grow, but when a billion years is condensed into 40 seconds a mesmerising dance is revealed."Oceans open and close, continents disperse and periodically recombine to form immense supercontinents."Earth scientists from every continent have collected and published data, often from inaccessible and remote regions, that Dr Andrew Merdith and his collaborators have assimilated over the past four years to produce this billion-year model.It will allow scientists to better understand how the interior of the Earth convects, chemically mixes and loses heat via seafloor spreading and volcanism. The model will help scientists understand how climate has changed, how ocean currents altered and how nutrients fluxed from the deep Earth to stimulate biological evolution.Professor Müller said: "Simply put, this complete model will help explain how our home, Planet Earth, became habitable for complex creatures. Life on Earth would not exist without plate tectonics. With this new model, we are closer to understanding how this beautiful blue planet became our cradle." | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209151850.htm | High CO2 to slow tropical fish move to cooler waters | Under increasing global warming, tropical fish are escaping warmer seas by extending their habitat ranges towards more temperate waters. | But a new study from the University of Adelaide, published in "Every summer hundreds of tropical fish species extend their range to cooler and temperate regions as the waters of their natural habitat become a little too warm for comfort," says lead author Ericka Coni, PhD student in the University's School of Biological Sciences. "For at least two decades, Australian temperate reefs have been receiving new guests from the tropics."As a result of warming, we also see warm-temperate long-spined sea urchins increasing in numbers in southeast Australia, where they overgraze kelp forests and turn them into deserts known as 'urchin barrens'. Coral reef fishes that are expanding their ranges to temperate Australia prefer these barrens over the natural kelp habitats."But what we don't know is how expected ocean acidification, in combination with this warming, will change the temperate habitat composition and consequently the rate of tropical species range-extension into cooler water ecosystems."The researchers hypothesised that these two divergent global change forces -- warming and acidification -- play opposing effects on the rate of tropicalisation of temperate waters."We know that as oceans warm they also acidify, because they absorb about a third of the CO"We also know that calcifying species like sea urchins are typically challenged by seawater with reduced pH levels resulting from elevated COThe research team, which also included Camilo Ferreira and Professor Sean Connell from the University of Adelaide, and Professor David Booth from the University of Technology Sydney, used two 'natural laboratories' to study ocean warming (tropicalisation hotspots on the south-eastern Australian coast) and ocean acidification predicted for the end of this century (natural COThey found that sea urchin numbers were reduced by 87% under elevated CO"Our study highlights that it is critical to study climate stressors together -- we show that ocean acidification can mitigate some of the ecological effects of ocean warming," says Professor Nagelkerken."For south-eastern Australia, and likely other temperate waters, this means that ocean acidification could slow down the tropicalisation of temperate ecosystems by coral reef fishes."But in the meantime, if left unabated, these tropical species could increase competition with local temperate species under climate change and reduce their populations."In the short-term we need to take steps to preserve kelp forests to help maintain the biodiversity and populations of temperate species and reduce the invasion of tropical species." | Climate | 2,021 |
February 9, 2021 | https://www.sciencedaily.com/releases/2021/02/210209083718.htm | Early Indian monsoon forecasts could benefit farmers | Farmers in India should be provided with early forecasts of expected variations in the monsoon season in order to reduce crop losses, scientists say. | Researchers at the University of Reading and the European Centre for Medium-range Weather Forecasts (ECMWF) led the first ever in-depth study into how accurately ECMWF's latest long-term global weather forecasting system can predict when the summer monsoon will start, and how much rainfall it will bring.They found the model provided accurate forecasts a month in advance for the timing of the monsoon in India's major agricultural regions. Providing this information to farmers could help them prepare earlier for unexpected heavy rainfall or extended dry periods, both of which regularly destroy crops in India.Dr Amulya Chevuturi, a monsoon researcher at the University of Reading and lead author of the study, said: "The Indian monsoon brings around 80% of India's annual rainfall, so even small variations in the timing of its arrival can have a huge impact on agriculture. Accurately predicting these year-to-year variations is challenging, but could be the difference between prosperity or poverty for many families."The forecasting accuracy we identified in India's main agricultural regions provides a clear opportunity for this system to make a positive difference to people's lives. A month's warning of a drought or deluge is valuable time to understand the likely impact on water availability and for farmers to make provisions to reduce the threat to food supplies."Better forecasts save lives, and this kind of in-depth global analysis is only possible when the best scientists and leading research institutes work together for the benefit of the whole planet."The Indian monsoon season starts around 1 June every year, beginning in south west India before spreading across the whole subcontinent.Scientists looked at 36 years' worth of monsoon data to evaluate for the first time the effectiveness of the ECMWF's latest seasonal forecasting system -- SEAS5 -- in predicting how the Indian monsoon would differ from the long-term average.The team compared forecasts from 1 May each year from 1981-2016 with actual observations of the monsoons that followed.Their study, published in It also identified deficiencies in the system that could pave the way for model improvements, potentially providing more detailed and accurate seasonal long-term monsoon forecasts.The study showed the forecasts tended to overestimate rainfall over the mountainous Western Ghats and Himalayan regions, and underestimated rainfall along the plains of the river Ganges in the north of the country, and its delta at the Bay of Bengal.However, the forecasts were correct for the monsoon rainfall pattern across India, making them useful for planning purposes. | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208185117.htm | Biologists uncover forests' unexpected role in climate change | New research from West Virginia University biologists shows that trees around the world are consuming more carbon dioxide than previously reported, making forests even more important in regulating the Earth's atmosphere and forever shift how we think about climate change. | In a study published in the "This study really highlights the role of forests and their ecosystems in climate change," said Thomas, interim associate provost for graduate academic affairs. "We think of forests as providing ecosystem services. Those services can be a lot of different things -- recreation, timber, industry. We demonstrate how forests perform another important service: acting as sinks for carbon dioxide. Our research shows that forests consume large amounts of carbon dioxide globally. Without that, more carbon dioxide would go into the air and build up in the atmosphere even more than it already is, which could exacerbate climate change. Our work shows yet another important reason to preserve and maintain our forests and keep them healthy."Previously, scientists have thought that trees were using water more efficiently over the past century through reduced stomatal conductance -- meaning trees were retaining more moisture when the pores on their leaves began closing slightly under rising levels of carbon dioxide.However, following an analysis using carbon and oxygen isotopes in tree rings from 1901 to 2015 from 36 tree species at 84 sites around the world, the researchers found that in 83% of cases, the main driver of trees' increased water efficiency was increased photosynthesis -- they processed more carbon dioxide. Meanwhile, the stomatal conductance only drove increased efficiency 17% of the time. This reflects a major change in how trees' water efficiency has been explained in contrast to previous research."We've shown that over the past century, photosynthesis is actually the overwhelming driver to increases in tree water use efficiency, which is a surprising result because it contradicts many earlier studies," Mathias said. "On a global scale, this will have large implications potentially for the carbon cycle if more carbon is being transferred from the atmosphere into trees."Since 1901, the intrinsic water use efficiency of trees worldwide has risen by approximately 40% in conjunction with an increase of approximately 34% in atmospheric carbon dioxide. Both of these characteristics increased approximately four times faster since the 1960s compared to the previous years.While these results show the rise in carbon dioxide is the main factor in making trees use water more efficiently, the results also vary depending on temperature, precipitation and dryness of the atmosphere. These data can help refine models used to predict the effects of climate change on global carbon and water cycles."Having an accurate representation of these processes is critical in making sound predictions about what may happen in the future," Mathias said. "This helps us get a little closer to making those predictions less uncertain."The study is a product of the researchers' seven-year research collaboration during Mathias' time as a doctoral student. After graduating from WVU, Mathias joined University of California, Santa Barbara as a postdoctoral researcher."Since moving to California, my work has taken a turn from being in the field, collecting measurements, analyzing data and writing manuscripts," Mathias said. "My new position is more focused on ecological theory and ecosystem modeling. Instead of measuring plants, I form hypotheses and seek out answers to questions using computer models and math."In the future, Mathias aspires to become a professor at a research university to continue these research pursuits."I would love to run my own lab at a university, mentor graduate students and pursue research questions to continue building on the work we've already accomplished. There's been a lot of progress in our field. There are also an infinite number of questions that are relevant moving forward," Mathias said. "I owe everything to my time and training from the people at WVU. My long-term goal is to be in a position where I can continue moving the field forward while giving back through teaching and mentoring students." | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208161945.htm | How rocks rusted on Earth and turned red | How did rocks rust on Earth and turn red? A Rutgers-led study has shed new light on the important phenomenon and will help address questions about the Late Triassic climate more than 200 million years ago, when greenhouse gas levels were high enough to be a model for what our planet may be like in the future. | "All of the red color we see in New Jersey rocks and in the American Southwest is due to the natural mineral hematite," said lead author Christopher J. Lepre, an assistant teaching professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University-New Brunswick. "As far as we know, there are only a few places where this red hematite phenomenon is very widespread: one being the geologic 'red beds' on Earth and another is the surface of Mars. Our study takes a significant step forward toward understanding how long it takes for redness to form, the chemical reactions involved and the role hematite plays."The research by Lepre and a Columbia University scientist is in the journal Lepre demonstrated that hematite concentrations faithfully track 14.5 million years of Late Triassic monsoonal rainfall over the Colorado Plateau of Arizona when it was on the ancient supercontinent of Pangea. With this information, he assessed the interrelationships between environmental disturbances, climate and the evolution of vertebrates on land.Lepre examined part of a 1,700-foot-long rock core from the Chinle Formation in the Petrified Forest National Park in Arizona (the Painted Desert) that is housed at Rutgers. Rutgers-New Brunswick Professor Emeritus Dennis V. Kent examined the same core for a Rutgers-led study that found that gravitational tugs from Jupiter and Venus slightly elongate Earth's orbit every 405,000 years and influenced Earth's climate for at least 215 million years, allowing scientists to better date events like the spread of dinosaurs.Lepre measured the visible light spectrum to determine the concentration of hematite within red rocks. To the scientists' knowledge, it is the first time this method has been used to study rocks this old, dating to the Late Triassic epoch more than 200 million years ago. Many scientists thought the redness was caused much more recently by the iron in rocks reacting with air, just like rust on a bicycle. So for decades, scientists have viewed hematite and its redness as largely unimportant."The hematite is indeed old and probably resulted from the interactions between the ancient soils and climate change," Lepre said. "This climate information allows us to sort out some causes and effects -- whether they were due to climate change or an asteroid impact at Manicouagan in Canada, for example -- for land animals and plants when the theropod dinosaurs (early ancestors of modern birds and Tyrannosaurus rex) were rising to prominence."The scientists, in collaboration with Navajo Nation members, have submitted a multi-million dollar grant proposal to retrieve more cores at the Colorado Plateau that will include rocks known to record a very rapid atmospheric change in carbon dioxide similar to its recent doubling as a result of human activity. | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208134425.htm | Radiative cooling and solar heating from one system, no electricity needed | Passive cooling, like the shade a tree provides, has been around forever. | Recently, researchers have been exploring how to turbo charge a passive cooling technique -- known as radiative or sky cooling -- with sun-blocking, nanomaterials that emit heat away from building rooftops. While progress has been made, this eco-friendly technology isn't commonplace because researchers have struggled to maximize the materials' cooling capabilities.New research led by University at Buffalo engineers makes significant progress in this area.A study published Feb. 8 in the journal While the system tested was only 70 centimeters (27.5 inches) squared, it could eventually be scaled up to cover rooftops, engineers say, with the goal of reducing society's reliance on fossil fuels for cooling and heating. It also could aid communities with limited access to electricity."There is a great need for heating and cooling in our daily life, especially cooling in the warming world," says the study's lead author Qiaoqiang Gan, PhD, professor of electrical engineering in the UB School of Engineering and Applied Sciences.The research team includes Zongfu Yu, PhD, University of Wisconsin-Madison; Boon Ooi, PhD, King Abdullah University of Science and Technology (KAUST) in Saudi Arabia; and members of Gan's lab at UB, and Ooi's lab at KAUST.The system consists of what are essentially two mirrors, made of 10 extremely thin layers of silver and silicon dioxide, which are placed in a V-shape.These mirrors absorb incoming sunlight, turning solar power from visible and near-infrared waves into heat. The mirrors also reflect mid-infrared waves from an "emitter" (a vertical box in between the two mirrors), which then bounces the heat they carry into the sky."Since the thermal emission from both surfaces of the central thermal emitter is reflected to the sky, the local cooling power density on this emitter is doubled, resulting in a record high temperature reduction," says Gan."Most radiative cooling systems scatter the solar energy, which limits the system's cooling capabilities," Gan says. "Even with a perfect spectral selection, the upper limit for the cooling power with an ambient temperature of 25 degrees Celsius is about 160 watts per square meter. In contrast, the solar energy of about 1000 watts per square meter on top of those systems was simply wasted."Gan co-founded a spinoff company, Sunny Clean Water LLC, which is seeking partners to commercialize this technology."One of the key innovations of our system is the ability to separate and retain the solar heating and radiative cooling at different components in a single system," says co-first author Lyu Zhou, a PhD candidate in electrical engineering in the School of Engineering and Applied Sciences. "During the night, radiative cooling is easy because we don't have solar input, so thermal emissions just go out and we realize radiative cooling easily. But daytime cooling is a challenge because the sun is shining. In this situation, you need to find strategies to separate solar heating from the cooling area."The work builds upon previous research Gan's lab led that involved creating a cone-shaped system for electricity-free cooling in crowded cities to adapt to climate change."The new double-sided architecture realized a record local cooling power density beyond 280 watts per square meter. Under standard atmospheric pressure with no vacuum thermal isolation, we realized a temperature reduction of 14.5 degrees Celsius below the ambient temperature in a laboratory environment, and over 12 degrees Celsius in an outdoor test using a simple experimental system," says the other co-first author, Haomin Song, PhD, a research assistant professor of electrical engineering in the School of Engineering and Applied Sciences."Importantly, our system does not simply waste the solar input energy. Instead, the solar energy is absorbed by the solar spectral selective mirrors, and it can be used for solar water heating, which is widely used as an energy efficient device in developing countries," says Gan. "It can retain both the solar heating and radiative cooling effects in a single system with no need of electricity. It's really sort of a 'magic' system of ice and fir."The research team will continue to investigate ways to improve the technology, including examining how to capture enough solar power to boil water, making it suitable for drinking.The work was supported by funding from the U.S. National Science Foundation's Thermal Transport Processes program. | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208114317.htm | Potential for misuse of climate data a threat to business and financial markets | The findings are published in the journal, | Regulators and governments -- both domestic and international -- are increasingly requiring that businesses assess and disclose their vulnerability to the physical effects of climate change, for example, increased drought, bushfires and sea level rise."People are making strategically material decisions on a daily basis, and raising debt or capital to finance these, but the decisions may not have properly considered climate risk," said lead author Dr Tanya Fiedler from the University of Sydney Business School."To assess the physical risks of climate change, businesses are referencing climate models, which are publicly available but complex. The problem arises when this information is used for the purpose of assessing financial risk, because the methodologies of those undertaking the risk assessment can be 'black boxed' and in some instances are commercial in confidence. This means the market is unable to form a view."Co-author on the paper, Professor Andy Pitman from the University of New South Wales, said: "Businesses want to know which of their assets and operations are at risk of flooding, cyclones or wind damage and when, but providing that information using existing global climate models is a struggle. There is, of course, very useful information available from climate models, but using it in assessing business risk requires a bespoke approach and a deep engagement between business and climate modellers."Professor Pitman, Director of the ARC Centre of Excellence for Climate Extremes, added: "A whole host of issues can trip up the unwary, ranging from the type of model, how it was set up, how changes in greenhouse gases were represented, what time period is being considered and how "independent" of each other the different models truly are."To address the gap between science and business, a paradigm shift is needed.Professor Christian Jakob from Monash University, another co-author of the study, said: "Climate modelling needs to be elevated from a largely research-focussed activity to a level akin to that of operational weather forecasting -- a level that is of tangible and practical value to business."Without such an approach, the paper highlights some of the unintended consequences arising from climate information being used inappropriately."As with any form of decision-making, businesses could be operating under a false sense of security that arises when non-experts draw conclusions believed to be defensible, when they are not," Dr Fiedler, an expert at the University of Sydney's Discipline of Accounting, said."Our study proposes a new approach with deep engagement between governments, business and science to create information that is fit for purpose. Until this happens, your best bet is to go to the source -- the climate modellers themselves." | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208114314.htm | Climate change: Erratic weather slows down the economy | If temperature varies strongly from day to day, the economy grows less. Through these seemingly small variations climate change may have strong effects on economic growth. This shows data analyzed by researchers from the Potsdam Institute for Climate Impact Research (PIK), Columbia University and the Mercator Research Institute on Global Commons and Climate Change (MCC). In a new study in | "We have known for a while that changes in annual mean temperature impacts macroeconomic growth," explains lead author Maximilian Kotz from PIK. "Yet now, for the first time, we're also able to show that day-to-day variations in temperature, i.e. short-term variability, has a substantial impact. If this variability increases by one degree Celsius, economic growth is reduced on average by 5 percentage-points."Particularly affected are economies in low-income regions of the global South, as co-author Leonie Wenz from PIK explains: "We find that familiarity with temperature variations is important: Economies in Canada or Russia, where average monthly temperature varies by more than 40°C within a year, seem better prepared to cope with daily temperature fluctuations than low-latitude regions such as parts of Latin America or Southeast Asia, where seasonal temperature differences can be as small as 3°C. This is likely because farmers and small business owners have cultivated resilience against temperature variability.""Furthermore, income protects against losses," Wenz adds. "Even if at similar latitude, economies in poor regions are more strongly affected when daily temperature fluctuates than their counterparts in rich regions." If the daily temperature deviates from seasonal expectations, fundamental elements of the economy are negatively impacted -- including crop yields, human health, sales and operational costs.Comparing each year's day-to-day temperature variability between 1979 and 2018 with the corresponding regional economic data, the researchers analyzed a total of 29,000 individual observations. "Rapid temperature variability is something completely different than long-term changes," explains Co-Author Anders Levermann from PIK and Columbia University, New York."The real problem caused by a changing climate are the unexpected impacts, because they are more difficult to adapt to. Farmers and other businesses around the world have started to adapt to climate change. But what if weather becomes simply more erratic and unpredictable? What we have shown is that erratic weather slows down the economy. Policy makers and industry need to take this into account when discussing the real cost of climate change." | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208114312.htm | Better understanding the reasons behind Arctic's amplified warming | It's clear that rising greenhouse gas emissions are the main driver of global warming. But on a regional level, several other factors are at play. That's especially true in the Arctic -- a massive oceanic region around the North Pole which is warming two to three times faster than the rest of the planet. One consequence of the melting of the Arctic ice cap is a reduction in albedo, which is the capacity of surfaces to reflect a certain amount of solar radiation. Earth's bright surfaces like glaciers, snow and clouds have a high reflectivity. As snow and ice decrease, albedo decreases and more radiation is absorbed by the Earth, leading to a rise in near-surface temperature. | The other regional, yet much more complex factor that scientists need to pay detailed attention to relates to how clouds and aerosols interact. Aerosols are tiny particles suspended in the air; they come in a wide range of sizes and compositions and can occur naturally -- such as from sea spray, marine microbial emissions or forest fires (like in Siberia) -- or be produced by human activity, for exemple from the combustion of fossil fuels or agriculture. Without aerosols, clouds cannot form because they serve as the surface on which water molecules form droplets. Owing to this role, and more specifically to how they affect the amount of solar radiation that reaches the Earth surface, and the terrestrial radiation that leaves the Earth, aerosols are an essential element in regulating the climate and Arctic climate in particular.In a paper published in Schmale has carried out several research expeditions to the North Pole, most recently in early 2020 on the German icebreaker Polarstern. She saw first-hand that the Arctic climate tends to change fastest in the winter -- despite there being no albedo during this period of 24-hour darkness. Scientists still don't know why. One reason could be that clouds present in winter are reflecting the Earth's heat back down to the ground; this occurs to varying degrees depending on natural cycles and the amount of aerosol in the air. That would lift temperatures above the Arctic ice mass, but the process is extremely complicated due to the wide range of aerosol types and differences in their capacity to reflect and absorb light. "Few observations have been made on this phenomenon because, in order to conduct research in the Arctic in the wintertime, you have to block off an icebreaker, scientists and research equipment for the entire season," says Schmale.Although many research expeditions have already been carried out in the Arctic, a lot remains to be explored. One option could be to collect all the discoveries made so far on Arctic warming and use them to improve existing weather models. "A major effort is needed right away, otherwise we'll always be one step behind in understanding what's going on. The observations we've already made could be used to improve our models. A wealth of information is available, but it hasn't been sorted through in the right way to establish links between the different processes. For instance, our models currently can't tell us what kinds of aerosols contribute the most to climate change, whether local or anthropogenic," says Schmale.In their paper, the research team puts forth three steps that could be taken to gain better insight into the Arctic climate and the role played by aerosols. They suggest creating an interactive, open-source, virtual platform that compiles all Arctic knowledge to date. They point to the International Arctic Systems for Observing the Atmosphere (IASOA) program as an example; the IASOA coordinates the activities of individual Arctic observatories to provide a collaborative international network for Arctic atmospheric research and operations. "We need to improve our climate models because what's happening in the Arctic will eventually spread elsewhere. It's already affecting the climate in other parts of the northern hemisphere, as we've seen with the melting glaciers and rising sea levels in Greenland. And to develop better models, a better understanding of aerosols' role will be crucial. They have a major impact on the climate and on human health," says Schmale. | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208114257.htm | Uncovering how some corals resist bleaching | Coral reefs are beautiful and diverse ecosystems that power the economies of many coastal communities. They're also facing threats that are driving their decline, including the planet's warming waters. | This threat hit extreme levels in 2015, when high temperatures were turning corals white around the globe. Kaneohe Bay in Hawaii was hit hard; nearly half of its corals bleached.Hidden in the aftermath of this extreme event, however, were biochemical clues as to why some corals bleached while others were resistant, information that could help reefs better weather warming waters in the future. These clues have now been uncovered by researchers at Michigan State University and the University of Hawaii at Manoa."It was kind of horrifying," said coral biologist Crawford Drury, who witnessed 2015's bleaching event from Florida before joining UH Manoa's Hawaii Institute for Marine Biology, or HIMB. "It's disheartening to watch, but I try to think of it as an opportunity."How this disturbing event became an opportunity is now clear thanks to a Feb. 8 report in The researchers discovered chemical signatures in the corals' biology, or biomarkers, that are present in organisms that were most resistant to the bleaching. This previously hidden insight could help researchers and conservationists better restore and protect reefs around the world."Usually, we think of biomarkers as signatures of disease, but this could be a signature of health," said MSU's Robert Quinn, an assistant professor in the Department of Biochemistry and Molecular Biology. "This could help us restore reefs with the most resistant stock."Corals are symbiotic communities where coral animal cells build homes for algae that provide them energy and create their colors. When corals bleach, however, the algae are lost and leave behind skeletons that are susceptible to disease and death.This symbiosis also plays a role in a coral's resistance and resilience to bleaching, which HIMB was in a unique position to investigate -- literally. The institute sits right next to the reef, enabling experiments in real time."The reef is about 100 feet away," Drury said. "I could be there in 30 seconds."During the 2015 bleaching event, researchers in the Gates Coral Lab at HIMB had tagged individual corals to keep tabs on them. Because most of the corals recovered, the team could follow them over time."We think about it as a biological library," said Drury, the principal investigator with the Gates Coral Lab. "It was set up by researchers in our lab who knew it would be very valuable."Following the bleaching, the team compared and contrasted coral samples in the wild, noting how the organisms responded and recovered, making some surprising observations along the way. For example, neighboring corals could behave completely differently in response to high temperatures. One coral could bleach completely while its neighbor maintained a healthy golden hue.To understand why, Drury and HIMB postdoctoral researcher Ty Roach, the lead author of the study, sent samples to Quinn at MSU. Here, Quinn and his team could thoroughly analyze the biochemicals of corals collected from this biological library using a method called metabolomics."I'm known more for my medical work," said Quinn, who studies the biochemistry of health and disease in humans. "But I've always loved ocean science. My background is in marine microbiology."If the coral samples are the books in the library, Quinn's lab used sophisticated equipment to reveal the biochemical language within. In particular, his team used tools known as mass spectrometers to understand what set resistant corals apart from susceptible ones."The corals are completely different in their chemistry, but you can't tell until you run the mass spec," Quinn said. "These mass specs are some of the most advanced technology on the planet."Quinn's team found that corals that were resistant to bleaching and those that were susceptible hosted two different communities of algae. The distinguishing feature between these algal populations was found in their cells, in compounds known as lipids.The researchers' metabolomic analysis detected two different lipid formulations. Bleaching-resistant corals featured algae that have what are known as saturated lipids. Susceptible corals had more unsaturated lipids."This is not unlike the difference between oil and margarine, the latter having more saturated fat, making it solid at room temperature," Quinn said.This discovery poses all sorts of new questions for researchers: How do the corals get these different algae? Is this difference unique to Hawaiian corals or can it be found elsewhere? How can researchers promote the growth and proliferation of resilient corals in a warming world?"Mass specs are such incredible machines and reveal intricate details of the chemistry involved. The biology is really the hard part." Quinn said. "We're working on new grants. There are so many avenues to explore."This initial project was funded by the Paul G. Allen Family Foundation."This collaboration has been a great opportunity to ask and answer questions," Drury said. "Hopefully, we're just getting started."In the meantime, having this chemical information is promising for coral conservation. When conservationists reseed corals to help restore reefs, they can potentially select more resilient specimens."We can use natural resilience to better understand, support and manage coral reefs under climate change," Drury said."Conservation biology has some of the more successful stories in modern scientific history," Quinn said, pointing to the resurgence of elk in Virginia and bald eagles in Michigan. "Someday, maybe we can add corals to that list." | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208104624.htm | Ditching the car for walking or biking just one day a week cuts carbon footprint | Swapping the car for walking, cycling and e-biking even just one day a week makes a significant impact on personal carbon emissions in cities. | 'Active transport' -- cycling, e-biking or walking -- can help tackle the climate crisis according to a new study led by the University of Oxford's Transport Studies Unit and including researchers from Imperial's Centre for Environmental Policy as part of the EU-funded project PASTA: Physical Activity Through Sustainable Transport Approaches.Meeting greenhouse gas emissions reduction targets requires a significant move away from motorised transport. The team found that shifting to active transport could save as much as a quarter of personal carbon dioxide (COPublished in the journal Co-author Dr Audrey de Nazelle, from the Centre for Environmental Policy at Imperial, said: "Our findings suggest that, even if not all car trips could be substituted by bicycle trips, the potential for decreasing emissions is huge."This is one more piece of evidence on the multiple benefits of active travel, alongside our previous studies showing cycling is the best way to get around cities for both physical and mental health, and that promoting cycling helps tackle obesity. This should encourage different sectors to work together to create desirable futures from multiple health, environmental and social perspectives."The study followed nearly 2,000 people in seven European cities (Antwerp, Belgium; Barcelona, Spain; London, UK; Orebro, Sweden; Rome, Italy; Vienna, Austria; Zurich, Switzerland), collecting data on daily travel behaviour, journey purpose, as well as information on where their home and work or study location was, whether they have access to public transport, and socio-economic factors.The team performed statistical modelling of the data to assess how changes in active mobility, the 'main mode' of daily travel, and cycling frequency influenced mobility-related COLead researcher Dr Christian Brand , from the University of Oxford, said: "We found that those who switch just one trip per day from car driving to cycling reduce their carbon footprint by about 0.5 tonnes over a year, representing a substantial share of average per capita CO"If just 10% of the population were to change travel behaviour, the emissions savings would be around 4% of lifecycle COThe largest benefits from shifts from car to active travel were for business travel, followed by social and leisure trips, and commuting to work or place of study. These results also showed that those who already cycled had 84% lower COFor the cities in this study, average per capita (per person) CODr Brand said: "A typical response to the climate crisis is to 'do something', such as planting more trees, or switching to electric vehicles. While these are important and effective, they are neither sufficient nor fast enough to meet our ambitious climate targets."Doing more of a good thing combined with doing less of a bad thing -- and doing it now -- is much more compliant with a 'net zero' pathway and preserving our planet's and our own futures. Switching from car to active mobility is one thing to do, which would make a real difference, and we show here how good this can be in cities."The team say this will not only be good for the climate, but also for reducing social inequalities and improving public health and quality of urban life in a post-COVID-19 world.Dr de Nazelle said: "To improve active travel take-up, cities across the world will need to increase investment in high-quality infrastructure for pedestrians and cyclists and incorporate policy and planning concepts that require a fairly radical rethink of our cities."This is in turn likely to reduce inequalities, because the concepts involve mixing different population groups rather than maintaining the model of residential zoning by socioeconomic status currently used." | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208085454.htm | Coal and COVID-19: How the pandemic is accelerating the end of fossil power generation | COVID-19 has not only caused a temporary drop in global CO | "Coal has been hit harder by the Corona crisis than other power sources -- and the reason is simple," explains lead author Christoph Bertram from the Potsdam Institute for Climate Impact Research (PIK). "If demand for electricity drops, coal plants are usually switched off first. This is because the process of burning fuels constantly runs up costs. The plant operators have to pay for each single ton of coal. In contrast, renewable power sources such as wind and solar plants, once built, have significantly lower running costs -- and keep on operating even if the demand is reduced."This way, fossil fuels were partly squeezed out of the electricity generation mix in 2020 and global COThe researchers estimate that it's likely that emissions will not reach the all-time high of 2018 anymore. "Due to the ongoing crisis, we expect that 2021 electricity demand will be at about 2019's levels, which, given ongoing investments into low-carbon generation means lower fossil generation than in that year," says co-author Gunnar Luderer from PIK. "As long as this clean electricity generation growth exceeds increases in electricity demand, COWhile the power sector has seen a dynamic transformation process even before the advent of COVID-19, the pandemic has weakened the market position of coal-fired power generation and illustrated its vulnerability."Our research shows that investing in fossil-fueled power is not only environmentally irresponsible -- it is economically very risky," says co-author Ottmar Edenhofer, Director of both PIK and the Mercator Research Institute on Global Commons and Climate Change. "In the end, it will certainly take carbon pricing to cut emissions at the required pace and stabilize our Climate. Yet the impacts of the Corona crisis on the power generation sector have put political leaders in a unique position: Along with additional policies such as eliminating subsidies for fossil fuels and increasing investments in wind and solar power, it is now easier than ever before to put an end to high-carbon electricity." | Climate | 2,021 |
April 27, 2021 | https://www.sciencedaily.com/releases/2021/04/210427135458.htm | Arctic stew: Understanding how high-latitude lakes respond to and affect climate change | To arrive at Nunavut, turn left at the Dakotas and head north. You can't miss it -- the vast tundra territory covers almost a million square miles of northern Canada. Relatively few people call this lake-scattered landscape home, but the region plays a crucial role in understanding global climate change. New research from Soren Brothers, assistant professor in the Department of Watershed Sciences and Ecology Center, details how lakes in Nunavut could have a big impact on carbon dioxide levels in the atmosphere, and it's not all bad news -- at least for now. Brothers examined 23 years of data from lakes near Rankin Inlet. He noted a peculiarity -- as the lakes warmed, their carbon dioxide concentrations fell. Most lakes are natural sources of carbon dioxide, but these lakes were now mostly near equilibrium with the atmosphere. | This was odd. The expected pattern is that warmer temperatures should trigger larger releases of greenhouse gases from lakes. In places like Alaska, centuries of accumulated plant material in the permafrost release a hoard of carbon as they thaw, and are consumed by microbes. Experiments have also shown that as waters warm, carbon dioxide production by microbes increases more quickly than carbon dioxide uptake by plants, throwing the system out of balance. Together, these processes should increase atmospheric greenhouse gas emissions from waterways, in theory anyway. So why not in Nunavut? There is no question that the first step in this Rube Goldberg machine is engaged ... the climate is warming. Why then, are the lakes near Rankin Inlet not belching out carbon?Pulling on good, thick parkas, Brothers and his team visited the lakes and came up with a few ideas as to why this is happening. First, they note that much of Nunavut is on the Canadian shield -- an ancient granitic bedrock where thin soils are unlikely to contain -- and thus release -- the massive stores of organic matter entering waterways elsewhere in the Arctic. Second, longer ice-free seasons might be changing the water chemistry and biology in ways that actually lower carbon dioxide concentrations, including longer growing seasons for plants (which take up carbon dioxide), and potentially better growing conditions for algae on the bottom of these shallow, clear lakes.Does this mean that nature has come to the climate rescue? Likely not -- other lakes around the world may still increase carbon dioxide emissions with warming, and the lakes in Nunavut might eventually catch up with them too. More likely, Brothers suggests that the link between ice cover duration and carbon dioxide concentrations might be buying us some time, before stronger positive feedbacks are unleashed between the planet's warming and its ecosystems. It may be a complicated process, but understanding this complexity helps scientists predict variations in how lakes are responding to -- and influencing -- climate change. It's a view under the hood, making planetary feedbacks and tipping points a little more predictable. While the long-term trajectory of greenhouse gas emissions from lakes is not settled, these results are an important piece of the puzzle in climate change science. | Climate | 2,021 |
February 8, 2021 | https://www.sciencedaily.com/releases/2021/02/210208085521.htm | How iodine-containing molecules contribute to the formation of atmospheric aerosols, affect climate | As part of a worldwide collaboration, Carnegie Mellon University chemists have helped discover that iodic acids can rapidly form aerosol particles in the atmosphere, giving scientists more knowledge of how iodine emissions can contribute to cloud formation and climate change. | "Essentially all uncertainty around climate change and the atmosphere has something to do with particles and cloud droplets," said Neil Donahue, Thomas Lord University Professor of Chemistry and a professor in the departments of Chemical Engineering, and Engineering and Public Policy. The Donahue lab has been a longtime member of the CERN CLOUD experiment, an international collaboration of scientists that use a special chamber at CERN in Switzerland to remedy that uncertainty by studying how cosmic rays affect the formation of particles and clouds in the atmosphere. The chamber allows researchers to precisely mix vaporous compounds and observe how particles form and grow from them.In a study published today in the journal "This represents a new pathway for particle formation, which in turn governs the properties of clouds in the marine atmosphere," Donahue said.Building on previous research his lab conducted on discovering a new rapid mechanism for atmospheric particle formation from nitric acid and ammonia vapors, Donahue and his team have now helped the CLOUD collaboration discover that the nucleation rates of iodic acid particles are very fast. This means that increasing concentrations of iodine-containing vapors in the atmosphere can lead to large increases in the number of particles that form clouds.Specifically, Donahue and his collaborators, including current Ph.D. candidates Mingyi Wang and Victoria Hofbauer, alumna Qing Ye and former postdoctoral scholar Dexian Chen, contributed their use of a state-of-the-art chemical ionization mass spectrometer that can measure the amount and composition of extremely small particles less than 10 nanometers in size just following their formation."The CMU measurements showed that the newly formed particles are composed largely of iodic acid, confirming that this critical molecule not only is present as a vapor while particles are forming but definitively drives their growth," Donahue said.While clouds forming may sound like a relatively benign outcome, clouds play an important role in regulating Earth's temperature because they are highly reflective. Much of the sun's energy is reflected by clouds back into space, keeping Earth from becoming too hot. However, that reflectivity can work both ways, which is a particular problem at Earth's poles. Typically, the white snow and ice surfaces reflect a lot of sunlight back into space, thus keeping the surface there cool. However, increased cloud formation in those regions can mean that the light reflected off the surface can be reflected back onto the ice and snow by the cloud cover."The Arctic is an especially vulnerable region, with twice the rate of warming and the huge consequences of both sea ice and ice sheet melting," Donahue said. He and his lab are already planning future research into the complex feedbacks between iodic acid and sulfur compounds and how these affect the polar atmosphere and climate change."We have a great deal more to learn in this area, especially regarding the interactions of the iodine compounds and particles, and dimethyl sulfide oxidation and its particle formation," Donahue said. | Climate | 2,021 |
February 5, 2021 | https://www.sciencedaily.com/releases/2021/02/210205192212.htm | Arctic stew: Understanding how high-latitude lakes respond to and affect climate change | To arrive at Nunavut, turn left at the Dakotas and head north. You can't miss it -- the vast tundra territory covers almost a million square miles of northern Canada. Relatively few people call this lake-scattered landscape home, but the region plays a crucial role in understanding global climate change. New research from Soren Brothers, assistant professor in the Department of Watershed Sciences and Ecology Center, details how lakes in Nunavut could have a big impact on carbon dioxide levels in the atmosphere, and it's not all bad news -- at least for now. Brothers examined 23 years of data from lakes near Rankin Inlet. He noted a peculiarity -- as the lakes warmed, their carbon dioxide concentrations fell. Most lakes are natural sources of carbon dioxide, but these lakes were now mostly near equilibrium with the atmosphere. | This was odd. The expected pattern is that warmer temperatures should trigger larger releases of greenhouse gases from lakes. In places like Alaska, centuries of accumulated plant material in the permafrost release a hoard of carbon as they thaw, and are consumed by microbes. Experiments have also shown that as waters warm, carbon dioxide production by microbes increases more quickly than carbon dioxide uptake by plants, throwing the system out of balance. Together, these processes should increase atmospheric greenhouse gas emissions from waterways, in theory anyway. So why not in Nunavut? There is no question that the first step in this Rube Goldberg machine is engaged ... the climate is warming. Why then, are the lakes near Rankin Inlet not belching out carbon?Pulling on good, thick parkas, Brothers and his team visited the lakes and came up with a few ideas as to why this is happening. First, they note that much of Nunavut is on the Canadian shield -- an ancient granitic bedrock where thin soils are unlikely to contain -- and thus release -- the massive stores of organic matter entering waterways elsewhere in the Arctic. Second, longer ice-free seasons might be changing the water chemistry and biology in ways that actually lower carbon dioxide concentrations, including longer growing seasons for plants (which take up carbon dioxide), and potentially better growing conditions for algae on the bottom of these shallow, clear lakes.Does this mean that nature has come to the climate rescue? Likely not -- other lakes around the world may still increase carbon dioxide emissions with warming, and the lakes in Nunavut might eventually catch up with them too. More likely, Brothers suggests that the link between ice cover duration and carbon dioxide concentrations might be buying us some time, before stronger positive feedbacks are unleashed between the planet's warming and its ecosystems. It may be a complicated process, but understanding this complexity helps scientists predict variations in how lakes are responding to -- and influencing -- climate change. It's a view under the hood, making planetary feedbacks and tipping points a little more predictable. While the long-term trajectory of greenhouse gas emissions from lakes is not settled, these results are an important piece of the puzzle in climate change science. | Climate | 2,021 |
February 5, 2021 | https://www.sciencedaily.com/releases/2021/02/210205150148.htm | Fingerprint for the formation of nitrous oxide emissions | Scientists led by Eliza Harris and Michael Bahn from the Institute of Ecology at the University of Innsbruck have succeeded in studying emissions of the greenhouse gas N | Nitrous oxide (NThe results provide researchers with unprecedented insights into the nitrogen cycle and the processes involved in the formation of the greenhouse gas NCrucial to the research success was the use of laser isotope spectroscopy, made possible through the FFG-funded project LTER-CWN. "Through this novel analytical technique, we can determine the isotopic composition of N | Climate | 2,021 |
February 5, 2021 | https://www.sciencedaily.com/releases/2021/02/210205121239.htm | Bioplastics in the sustainability dilemma | Plastics made from crops such as maize or sugarcane instead of fossil fuels are generally considered sustainable. One reason is that plants bind CO | As in previous analyses, the scientists used a global, flexible and modular economic model developed at the University of Bonn to simulate the impact of rising supply for bioplastics. The model is based on a world database (Global Trade Analysis Project). For their current study, the researchers modified the original model by disaggregating both conventional plastics and bioplastics, as well as additional crops such as maize and cassava. "This is crucial to better represent the bioplastics supply chain in major producing regions and assess their environmental impacts from a life cycle perspective," emphasizes agricultural engineer Dr. Neus Escobar, who conducted the study at the Institute for Food and Resource Economics (ILR) and the Center for Development Research (ZEF) at the University of Bonn and is now based at the International Institute for Applied Systems Analysis in Laxenburg (Austria).In the current study, she and her colleague Dr. Wolfgang Britz considered the loss of natural vegetation on a global scale. They made estimates of readily available land to be converted into productive uses at the region level and associated model parameters. In their previous publication, the Bonn scientists had already disaggregated the production of conventional plastics and bioplastics in Brazil, China, the EU and the U.S. -- the countries that lead the way in bioplastics production. In their current study, they also included Thailand, which is home of carbon-rich forests. Experts expect the Asian country to become a leading global producer of biodegradable and biobased plastics in the near future. "All these changes in the model are necessary to estimate global spillovers of policies or technologies," says Dr. Wolfgang Britz, who worked with his team on the extension of the model to derive sustainability indicators considering global land use change.The researchers simulated a total of 180 scenarios (36 scenarios per region) that varied according to the degree of bioplastics market penetration and other model parameters determining economywide responses. "We found that the carbon footprints of commercially available bioplastics are much larger than the values previously estimated in scientific literature and policy reports," says Neus Escobar.The reason: COThe overall calculations show that none of the regions is clearly better positioned than another to become a hub for sustainable bioplastics production. The largest land footprints are estimated for Chinese bioplastics, while the European Union has the largest average carbon footprint: Bioplastics produced in the EU take an average of 232.5 years to offset global CO"Our study shows that an expansion in bio-based production should be carefully assessed on a region-by-region case in order to understand potentially sustainability risks and trade-offs," says Neus Escobar. The authors emphasize that the proposed metrics can be used in the future to monitor the long-term sustainability of bioeconomic interventions globally. Among other things, the metrics could help identify where complementary policies are needed -- for example, to prevent deforestation.The study is thematically embedded in the Transdisciplinary Research Area (TRA) "Innovation and Technology for Sustainable Futures" at the University of Bonn. In six different TRAs, scientists from a wide range of faculties and disciplines come together to work on future-relevant research topics. Neus Escobar was a member of the Transdisciplinary Research Area during the study, Wolfgang Britz is a member of the "PhenoRob" Cluster of Excellence at the University of Bonn. | Climate | 2,021 |
February 5, 2021 | https://www.sciencedaily.com/releases/2021/02/210205121233.htm | Forests of the world in 3D | Primeval forests are of great importance for biodiversity and global carbon and water cycling. The three-dimensional structure of forests plays an important role here because it influences processes of gas and energy exchange with the atmosphere, whilst also providing habitats for numerous species. An international research team led by the University of Göttingen has investigated the variety of different complex structures that can be found in the world's forests, as well as the factors that explain this diversity. The results have been published in | The researchers investigated the structure of primeval forests on several continents in different climate zones. To achieve this, they spent two years travelling to remote primeval forest areas around the world to record the structure of the forests with the help of 3D laser scanners. A laser scanner captures the environment with the help of a laser beam and thus builds a 3D representation of the forest. This allows important metrics to be calculated to describe the structure. They found that the global variability of forest structures can be explained to a large extent by the amount of precipitation and thus by the availability of water in the different ecosystems. Based on these findings and with the help of climate data, they were able to create maps of the world's forests showing the global variability of structural complexity.The world maps describe the structures that forests can develop free from human influence. Only 30 percent of the world's forests are still primeval forests. "A long-term goal of our research is to better understand how human influence and climate change affect the forest, its structure and the processes linked to it. The structure of primeval forests is an important reference point for this," says first author Dr Martin Ehbrecht from the University of Göttingen. A particular focus here is the question of how changes in precipitation patterns due to climate change affect the structure of forests. "The importance of water for the formation of complex forest structures can be explained by various interacting mechanisms," says Ehbrecht. "The availability of water is an important driver of the diversity of tree species. The more tree species a forest holds, the more pronounced is the coexistence of different crown shapes and sizes of trees. This means that the space available for the crowns of trees can often be utilised more efficiently in species-rich forests, which makes the forest structure more complex."Tropical rainforests have a more complex structure than the deciduous and coniferous forests found in temperate zones, which are in turn generally more complex in structure than boreal coniferous forests such as those in Scandinavia, or subtropical forest savannahs in Africa. "Nevertheless, forests with high structural complexity can also be found in temperate zones, such as in areas with a high rainfall like the Pacific Northwest of the USA or in coastal forests of Chile," says Professor Ammer, senior author of the study and head of Silviculture and Forest Ecology of Temperate Zones at Göttingen University.The results of this study are an important starting point for further work. "With the help of satellite-based recording of 3-D forest structure, in the future it will be possible to precisely record the actual complexity of forests," says Ehbrecht. "This will make it possible to better understand the effects of forest management and climate change on the world's forests. Our world maps can serve as an important reference for this." | Climate | 2,021 |
February 5, 2021 | https://www.sciencedaily.com/releases/2021/02/210205085718.htm | Climate change may have driven the emergence of SARS-CoV-2 | Global greenhouse gas emissions over the last century have made southern China a hotspot for bat-borne coronaviruses, by driving growth of forest habitat favoured by bats. | A new study published today in the journal The study has revealed large-scale changes in the type of vegetation in the southern Chinese Yunnan province, and adjacent regions in Myanmar and Laos, over the last century. Climatic changes including increases in temperature, sunlight, and atmospheric carbon dioxide -- which affect the growth of plants and trees -- have changed natural habitats from tropical shrubland to tropical savannah and deciduous woodland. This created a suitable environment for many bat species that predominantly live in forests.The number of coronaviruses in an area is closely linked to the number of different bat species present. The study found that an additional 40 bat species have moved into the southern Chinese Yunnan province in the past century, harbouring around 100 more types of bat-borne coronavirus. This 'global hotspot' is the region where genetic data suggests SARS-CoV-2 may have arisen."Climate change over the last century has made the habitat in the southern Chinese Yunnan province suitable for more bat species," said Dr Robert Beyer, a researcher in the University of Cambridge's Department of Zoology and first author of the study, who has recently taken up a European research fellowship at the Potsdam Institute for Climate Impact Research, Germany.He added: "Understanding how the global distribution of bat species has shifted as a result of climate change may be an important step in reconstructing the origin of the COVID-19 outbreak."To get their results, the researchers created a map of the world's vegetation as it was a century ago, using records of temperature, precipitation, and cloud cover. Then they used information on the vegetation requirements of the world's bat species to work out the global distribution of each species in the early 1900s. Comparing this to current distributions allowed them to see how bat 'species richness', the number of different species, has changed across the globe over the last century due to climate change."As climate change altered habitats, species left some areas and moved into others -- taking their viruses with them. This not only altered the regions where viruses are present, but most likely allowed for new interactions between animals and viruses, causing more harmful viruses to be transmitted or evolve," said Beyer.The world's bat population carries around 3,000 different types of coronavirus, with each bat species harbouring an average of 2.7 coronaviruses -- most without showing symptoms. An increase in the number of bat species in a particular region, driven by climate change, may increase the likelihood that a coronavirus harmful to humans is present, transmitted, or evolves there.Most coronaviruses carried by bats cannot jump into humans. But several coronaviruses known to infect humans are very likely to have originated in bats, including three that can cause human fatalities: Middle East Respiratory Syndrome (MERS) CoV, and Severe Acute Respiratory Syndrome (SARS) CoV-1 and CoV-2.The region identified by the study as a hotspot for a climate-driven increase in bat species richness is also home to pangolins, which are suggested to have acted as intermediate hosts to SARS-CoV-2. The virus is likely to have jumped from bats to these animals, which were then sold at a wildlife market in Wuhan -- where the initial human outbreak occurred.The researchers echo calls from previous studies that urge policy-makers to acknowledge the role of climate change in outbreaks of viral diseases, and to address climate change as part of COVID-19 economic recovery programmes."The COVID-19 pandemic has caused tremendous social and economic damage. Governments must seize the opportunity to reduce health risks from infectious diseases by taking decisive action to mitigate climate change," said Professor Andrea Manica in the University of Cambridge's Department of Zoology, who was involved in the study."The fact that climate change can accelerate the transmission of wildlife pathogens to humans should be an urgent wake-up call to reduce global emissions," added Professor Camilo Mora at the University of Hawai'i at Manoa, who initiated the project.The researchers emphasised the need to limit the expansion of urban areas, farmland, and hunting grounds into natural habitat to reduce contact between humans and disease-carrying animals.The study showed that over the last century, climate change has also driven increases in the number of bat species in regions around Central Africa, and scattered patches in Central and South America. | Climate | 2,021 |
February 4, 2021 | https://www.sciencedaily.com/releases/2021/02/210204143218.htm | In a desert seared by climate change, burrowers fare better than birds | In the arid Mojave Desert, small burrowing mammals like the cactus mouse, the kangaroo rat and the white-tailed antelope squirrel are weathering the hotter, drier conditions triggered by climate change much better than their winged counterparts, finds a new study published today in | Over the past century, climate change has continuously nudged the Mojave's searing summer temperatures ever higher, and the blazing heat has taken its toll on the desert's birds. Researchers have documented a collapse in the region's bird populations, likely resulting from many bird species' inability to withstand these new hotter temperaturesHowever, the same team that documented the birds' decline has now found that small mammal populations in the desert have remained relatively stable since the beginning of the 20th century.Using computer models to simulate how birds and mammals respond to heat, the study team showed that small mammals' resilience is likely due to their ability to escape the sun in underground burrows and their tendency to be more active at night. As a result of these behaviors, small mammals have much lower "cooling costs" than birds, which have less capacity to escape the desert heat and need extra water to maintain a healthy body temperature."Scientists tend to assume that most species in a region experience the same exposure to temperature or precipitation changes, and that they all respond in the same way. But we're finding now that animals have diverse strategies for reducing their exposure to hot and dry conditions that could kill them," said study senior author Steven Beissinger, a University of California, Berkeley, professor of environmental science, policy and management and a researcher at the campus's Museum of Vertebrate Zoology. "You should see these differences most strongly in a harsh environment like the desert, where life is really on the edge."The findings are part of UC Berkeley's Grinnell Resurvey Project, an effort to revisit and document wildlife at sites in California first studied by UC Berkeley biologist Joseph Grinnell and his colleagues at the Museum of Vertebrate Zoology between 1904 and 1940. Grinnell's detailed field notes of the animal and plant life of the early 20th century have given modern-day biologists a glimpse into the ecology of the past, allowing them to document how climate change has impacted wildlife throughout the state."It's becoming clear that animals across the planet are responding to climate change by shifting where they live and shifting when they breed, and we're starting to get really strong evidence of population declines in certain areas that may be associated with warming," said lead author Eric Riddell, an assistant professor of ecology, evolution and organismal biology at Iowa State University. "Some estimates now suggest that one in six species will be threatened by climate change over the next century. Figuring out which species those are, what kind of traits they have, will be critical."In recent years, the Grinnell Resurvey Project has turned its focus to ecological change in the Mojave Desert, an area in Southern California and Nevada that is home to Death Valley and Joshua Tree national parks and the Mojave National Preserve. As a whole, the desert has seen an approximate 2 C (3.6 F) increase in average mean temperature and a 10 to 20% decrease in precipitation over the last century."Desert species have been thought to be relatively invulnerable to climate warming, but many desert species are already at or near their temperature and aridity tolerance limits. Each species also has different degrees of resilience," said study co-author Lori Hargrove, an ecologist at the San Diego Natural History Museum. "Climate change may seem minor, only a few degrees, but it has already had, and is having, direct and significant impacts on many species, each of which, in turn, affects other species, with cascading effects yet to be realized."While there was no such thing as GPS when Grinnell and his colleagues conducted their surveys, they left behind detailed field notes of landscape features like hills, mountains and streams, that have allowed current day scientists to pinpoint their locations to within less than a kilometer, even in desolate regions like the Mojave Desert."Sometimes they were very nice and left topo maps, but sometimes you have to do a little detective work," said Beissinger, who leads the Grinnell Resurvey Project. "For instance, they will say, 'We sampled at Horse Mountain.' Well, there are three Horse Mountains in California. So, we track down the Horse Mountain in the study region. And then you find out that they camped at the mouth of a creek. So, then you look at the old topo maps, and you see the creek. Using these details, we're able to recreate more or less where they were."Once the researchers identify a location, the next step is to take stock of what animals live there. To survey bird populations, researchers will pick a specific trail or route to walk for 1.5 miles and stop at defined intervals to record all the birds they see -- or, more likely, hear."You have to know your bird songs," Beissinger said.Small mammal surveys are a little trickier. Because small mammals are often more active at night and usually spend the daylight hours hiding away in burrows, researchers rely on live traps to get an idea of which animals are around.Co-author James Patton, a professor emeritus of integrative biology and curator in the Museum of Vertebrate Zoology at UC Berkeley, led the trapping efforts with his wife, Carol, in Mojave's Death Valley National Park. To sample a given location, Patton said that they would set a series of approximately 200 traps each night for four or five nights and record what they caught."To be a fieldworker, you have to have sufficient experience with the local fauna to know that you're sampling the diversity of habitats that are actually occupied. That means variations in plant community and substrate, such as whether the ground surface is sandy, rocky or hardpan," said Patton, who has been involved in the Grinnell Resurvey Project since its inception in 2003.Researchers on Beissinger's team have adapted statistical models that account for differences in survey methods and detection between Grinnell's time and today, allowing them to directly compare species diversity and prevalence between the early 20th century and now. The new study's findings are based on multiday surveys of 34 small mammal species at 90 sites and 135 bird species at 61 sites located primarily on Mojave Desert protected lands and national parks.In 2018, the team reported its findings that bird populations have declined precipitously, with the 61 sites losing, on average, 43% of the species that were there a century ago. However, according to the new trapping data, small mammal populations have not significantly changed since then."Mammals have shown this remarkable stability," Beissinger said. "It's really quite interesting that, in the same region, with the same level of climate change, these two very similar taxa have responded very differently to the changes taking place."Desert animals have devised a variety of different tricks for staying cool in the dry heat. Unlike humans, birds and small mammals do not sweat. However, some rely on other methods of evaporative cooling, such as panting or "gular flutter," a vibration of a bird's throat muscles that increases air flow. Others will avoid the heat by staying in the shade, or by building dens or burrows to hide from the sun. Some avoid the heat of the day altogether by being nocturnal.As a postdoctoral researcher at UC Berkeley, Riddell built computer models of 49 desert birds to calculate each species' body temperature and cooling needs under different desert conditions. Birds that the model predicted would have the greatest increase in cooling costs were also the ones that showed the greatest losses in field surveys -- particularly larger birds, and those that have an insect or animal diet.For the new study, Riddell built additional physiological models, this time for small mammals of the desert."The simulations estimate the head loads that animals experience and then calculates how much heat they need to gain or lose to maintain a stable body temperature," Riddell said. "It's very similar to how your house controls the temperature. You probably want to keep your house temperature pretty constant throughout the seasons, and keeping your house warm or cool depends on what your house is made of: What are its properties? How thick are the walls? How much sun hits it? These are the types of characteristics that I measured for birds and mammals."For instance, he said, a black crow will absorb more sunlight than a lighter colored bird. However, the shape of the animal, the thickness of the plumage or fur and the length of the individual fibers will all determine how much sunlight is able to pass through the feathers and hit the skin of the animal.For small mammals, Riddell was also interested in how quickly heat is able to transfer through their fur. To calculate this, he used specimens currently stored at the Museum of Vertebrate Zoology. By placing the fur samples on a heated device, and placing thermocouples at the tips of the hairs, he was able to get an estimate of each animal's thermal conductance."Thermal conductance is basically how quickly something transfers heat with its environment," Riddell said. "A big, fluffy mammal might transfer heat very slowly, whereas an animal with very sparse or short fur, like a ground squirrel, might transfer heat quickly."The models also included different heat sources an animal might be exposed to, such as direct solar radiation, solar radiation reflected from the ground, and infrared radiation from the ground, known as longwave radiation.According to the models, cooling costs were, on average, about 3.3-fold higher for birds than they were for small mammals. Higher temperatures associated with climate change increased cooling costs by 58% for birds, but only 17% for mammals. This was largely due to the fact that the small mammals can retreat to underground burrows during the hottest parts of the day."A lot of the difference in cooling costs is related to what we call microhabitat differences. Small mammals are able to go underground where it is much cooler, and they're not being exposed to the direct sunlight, which heats up the bodies of the birds," Beissinger said. "These microgeographic variations in their exposure make a big difference, and these variations need to be considered when we think about how climate change will impact individual species."To prevent further losses, Beissinger says it will be important to identify local refuges in the desert where species will be able to maintain themselves when temperatures soar. Reducing the demand on aquifers in the region may also prevent more desert springs from drying up, returning more water to the parched landscape."This study has made me realize just how complicated predicting the effects of climate change truly are," Riddell said. "It isn't just about where the landscape is warming and where it isn't warming. It's a really complex process that involves many aspects of an organism's biology, including their physiology, their behavior, their evolution -- it's all coupled. You need to take a really integrative approach to understand it." | Climate | 2,021 |
February 4, 2021 | https://www.sciencedaily.com/releases/2021/02/210204131402.htm | Human-elephant conflict in Kenya heightens with increase in crop-raiding | A new study led by the University of Kent's Durrell Institute of Conservation and Ecology (DICE) has found that elephants living around the world-famous Masai Mara National Reserve, Kenya, are crop-raiding closer to the protected area, more frequently and throughout the year but are causing less damage when doing so. | Findings show that the direct economic impact of this crop-raiding in the Trans Mara region has dropped, yet farmers have to spend more time protecting their fields, further reducing support for conservation in communities who currently receive few benefits from living with wildlife.The research published by The team of conservationists, led by Professor Bob Smith and DICE alumna Dr Lydia Tiller (Research and Science Manager, Save the Elephants), investigated the seasonal, temporal and spatial trends of elephant crop-raiding in the Trans Mara, Kenya during 2014-2015, comparing results to a previous DICE study from 1999 to 2000.The number of crop-raiding incidents increased by 49% over the 15 years, but crop damage per incident dropped by 83%. This could be because farmers are better prepared to frighten off elephants. It could also be because landcover change makes it harder for elephants to hide in forest patches, and this spread of farmland and loss of forest to illegal charcoal clearing means that more of the crop-raiding incidents are taking place closer to the protected area.Professor Smith said: 'Landcover change has had a major impact on where human-elephant conflict takes place. Better land-use planning and support for farmers would help reduce crop-raiding as well as people's tolerance of elephants.'Lydia Tiller said: 'The change in crop-raiding trends going from being highly seasonal during 1999-2000 when maize crops are ripe, to year-round during 2014-2015, is yet another demonstration of how climate change is affecting nature. With less natural vegetation available for elephants to eat in the Masai Mara, this is not surprising. Restoring elephants' feeding habitat in the park is vital to reducing human-elephant conflict in the area.' | Climate | 2,021 |
February 4, 2021 | https://www.sciencedaily.com/releases/2021/02/210204120117.htm | Global warming found to be culprit for flood risk in Peruvian Andes, other glacial lakes | As the planet warms, glaciers are retreating and causing changes in the world's mountain water systems. For the first time, scientists at the University of Oxford and the University of Washington have directly linked human-induced climate change to the risk of flooding from a glacial lake known as one of the world's greatest flood risks. | The study examined the case of Lake Palcacocha in the Peruvian Andes, which could cause flooding with devastating consequences for 120,000 residents in the city of Huaraz. The paper, published Feb. 4 in "The scientific challenge was to provide the clearest and cleanest assessment of the physical linkages between climate change and the changing flood hazard," said co-author Gerard Roe, a UW professor of Earth and space sciences.In 2016, Roe and colleagues developed a method to determine whether an individual glacier's retreat can be linked to human-induced climate change. The retreat of mountain glaciers has several consequences, including creating basins in the space left by the retreating glacier. Precipitation and meltwater collects in these basins to form glacial lakes. Recent work has shown a rapid worldwide growth in the number and size of high-elevation glacial lakes."We believe our study is the first to assess the full set of linkages between anthropogenic climate change and the changing glacial lake outburst flood hazard," Roe said. "The methods used in our study can certainly be applied to other glacial lakes around the world."The new study first calculated the role of human emissions in the observed temperature increase since the start of the industrial era around Palcaraju Glacier. It finds that human activity is responsible for 95% of the observed 1 degree Celsius (1.8 degrees Fahrenheit) warming in this region since 1880.The authors then used the UW-developed technique to assess the relationship between these warming temperatures and the observed long-term retreat of the glacier that has caused Lake Palcacocha to expand. Results show it is virtually certain, with greater than 99% probability, that human-induced climate change has caused Palcaraju Glacier's retreat.Lead author Rupert Stuart-Smith, a doctoral student at Oxford, then used two methods to assess the hazard of glacial lake outburst flooding, in which an avalanche, landslide or rockfall induces a tsunami wave that overtops the lake's banks, to pinpoint how Lake Palcacocha's growth affects the flood risk faced by the city of Huaraz below."We found that human influence on climate -- through greenhouse-gas emissions -- is responsible for virtually all of the warming that has been observed in the region," said Stuart-Smith, who spent the summer of 2019 at the UW. "The study shows that warming has caused the retreat of the Palcaraju Glacier, which in turn has greatly increased the flood risk."The study provides new evidence for an ongoing case in the German courts in which Saúl Luciano Lliuya, a farmer from Huaraz, has sued RWE, Germany's largest electricity producer, for its role in creating global warming. The suit seeks reimbursement for current and future flood-risk reduction measures."Crucially, our findings establish a direct link between emissions and the need to implement protective measures now, as well as any damages caused by flooding in the future," Stuart-Smith said.This is not the first time Huaraz has been threatened by climate change. In 1941, an outburst flood from Lake Palcacocha, resulting from an ice and rock slide, killed at least 1,800 people. The study also found this flood to be influenced by human-induced climate change -- making it one of the earliest identified fatal impacts of climate change.The lake's recent growth strains decades of engineering efforts since the 1970s to contain the lake's water."Around the world, the retreat of mountain glaciers is one of the clearest indicators of climate change," Roe said. "Outburst floods threaten communities in many mountainous regions, but this risk is particularly severe in Huaraz, as well as elsewhere in the Andes and in countries like Nepal and Bhutan, where vulnerable populations live in the path of the potential floodwaters." | Climate | 2,021 |
February 4, 2021 | https://www.sciencedaily.com/releases/2021/02/210204101651.htm | California's rainy season starting nearly a month later than it did 60 years ago | The start of California's annual rainy season has been pushed back from November to December, prolonging the state's increasingly destructive wildfire season by nearly a month, according to new research. The study cannot confirm the shift is connected to climate change, but the results are consistent with climate models that predict drier autumns for California in a warming climate, according to the authors. | Wildfires can occur at any time in California, but fires typically burn from May through October, when the state is in its dry season. The start of the rainy season, historically in November, ends wildfire season as plants become too moist to burn.California's rainy season has been starting progressively later in recent decades and climate scientists have projected it will get shorter as the climate warms. In the new study, researchers analyzed rainfall and weather data in California over the past six decades. The results show the official onset of California's rainy season is 27 days later than it was in the 1960s and the rain that does fall is being concentrated during the months of January and February."What we've shown is that it will not happen in the future, it's happening already," said Jelena Luković, a climate scientist at the University of Belgrade in Serbia and lead author of the new study. "The onset of the rainy season has been progressively delayed since the 1960s, and as a result the precipitation season has become shorter and sharper in California."The new study in AGU's journal The results suggest California's wildfire season, which has been getting progressively worse due to human-caused climate change, will last even longer in the years to come and Californians can expect to see more fires flaring up in the month of November. 2020 was California's worst wildfire season on record, with nearly 10,000 fires burning more than 4.2 million acres of land.An extended dry season means there is more overlap between wildfire season and the influx of Santa Ana winds that bring hot, dry weather to California in the fall. These winds can fan the flames of wildfires and increase the risk of late-season fires getting out of hand."It's not just a matter of making the vegetation drier and keeping all else equal," said Daniel Swain, a climate scientist at the University of California Los Angeles who was not involved in the study. "You're also increasing the number of opportunities for extremely dry vegetation and extremely strong offshore winds to coincide."The delay in the start of the rainy season is likely due to changes in the atmospheric circulation patterns that bring precipitation to the West Coast, according to the study authors. They found the atmospheric circulation pattern that dominates California during the summer is extending into fall across the north Pacific Ocean. This change is bringing more rain to the states of Washington and Oregon and leaving California high and dry.The changes mean Californians will need to better plan how they manage water resources and energy production -- a longer dry season means more irrigation is needed for crops in an already water-stressed state."All water-sensitive stakeholders should have this information and plan their management accordingly," Luković said. | Climate | 2,021 |
February 3, 2021 | https://www.sciencedaily.com/releases/2021/02/210203205329.htm | New global 'wind atlas' propels sustainable energy | Wind energy scientists at Cornell University have released a new global wind atlas -- a digital compendium filled with documented extreme wind speeds for all parts of the world -- to help engineers select the turbines in any given region and accelerate the development of sustainable energy. | This wind atlas is the first publicly available, uniform and geospatially explicit (datasets tied to locations) description of extreme wind speeds, according to the research, "A Global Assessment of Extreme Wind Speeds For Wind Energy Applications," published in "Cost-efficient expansion of the wind-energy industry is enabled by access to this newly released digital atlas of the extreme wind conditions under which wind turbines will operate at locations around the world," said Sara C. Pryor, professor in the Department of Earth and Atmospheric Sciences, who authored the paper with Rebecca J. Barthelmie, professor in the Sibley School of Mechanical and Aerospace Engineering. Both are faculty fellows at the Cornell Atkinson Center for Sustainability."This kind of information will ensure the correct selection of wind turbines for specific deployment," Pryor said, "and help ensure cost-efficient and dependable electricity generation from those turbines."Knowing extreme wind speeds is key to turbine design for cost effectiveness, proper turbine selection and structural integrity on any given site, said the researchers. Before, in many locations, extreme wind-load estimates on projects were uncertain due to limited on-site measurements.By the end of 2019, total global wind turbine installed capacity was more than 651 gigawatts (GW), according to the paper, thanks to 60 GW of recently built capacity -- of which nearly 90% was placed onshore. "Thus, wind is now generating over 1,700 terawatt hours of electricity per year or about 7.5% of the global electricity supply," Pryor said.Barthelmie and Pryor report that the United States carries 17% of the world's current wind energy installed capacity, while Europe (31%) and China (36%) carry more.There are now wind turbines generating carbon-free electricity in more than 90 countries, Pryor said.Development of research product was motivated by a need from the wind-energy industry, Barthelmie said. Quantifying extreme winds may also be useful in civil engineering applications and in structural reliability analyses for tall buildings and transportation systems -- including long-span bridges -- as well as for electricity generation and distribution."Further cost-efficient expansion of the wind-energy industry will be enabled by access to this newly released digital atlas," Pryor said.Funding for this research was provided by the U.S. Department of Energy (Grants DE-SC0016438 and DE-SC0016605) and was performed on the National Science Foundation's Extreme Science and Engineering Discovery Environment (XSEDE) computational resources (Award: TG-ATM170024). | Climate | 2,021 |
February 3, 2021 | https://www.sciencedaily.com/releases/2021/02/210203144527.htm | Drone and Landsat imagery shows long-term change in vegetation cover along intermittent river | In the Namib Desert in southwestern Africa, the Kuiseb River, an ephemeral river which is dry most of the year, plays a vital role to the region. It provides most of the vegetation to the area and serves as a home for the local indigenous people, and migration corridor for many animals. The overall vegetation cover increased by 33% between 1984 and 2019, according to a Dartmouth study published in | The study leveraged recent drone imagery and past satellite imagery to estimate past vegetation cover in this linear oasis of the Kuiseb River, a fertile area in the middle of one of the driest deserts on the earth. The findings are significant, as this is the first study to reconstruct decades of vegetation change over a long stretch of the river, rather than at just a few sites.The research was based on a senior thesis project by Bryn E. Morgan '17, first author of the study, who has a bachelor's degree in geography and chemistry from Dartmouth, and is now a Ph.D. student in the WAVES Lab at the University of California, Santa Barbara. She first visited the Namib Desert, which is located along the coast of Namibia, in 2015 as part of the environmental studies foreign studies program , led by study co-author Douglas T. Bolger, a professor and chair of environmental studies at Dartmouth. Morgan returned to the region on her own in 2016, to conduct this research while working out of the Gobabeb Namib Research Institute and continued this work after graduating from Dartmouth.The study area consisted of a 112-kilometer stretch of the lower Kuiseb River, which was comprised of 12 sites along the river, each of which was 500 meters wide. At each site, Morgan flew one to four unmanned aerial vehicle or drone flights to capture images of the woody vegetation cover along the river. One drone flight would take images with true color and then another flight would take images with false color using near infrared wavelengths of light, which are outside what our eyes can see. False color imagery allows one to distinguish vegetation from sand and soil, and differentiate the various types of vegetation and how healthy it may be.The drone imagery revealed that five species of trees are part of the vegetation cover in the area: Acacia (Vachellia) erioloba, Faidherbia albida, Euclea pseudebenus, Tamrix usneoides, and Salvadora persica. A. erioloba and F. albida have been named national conservation priorities and their pods are an important food source to the livestock of the Topnaar (?Aonin), the indigenous people who live along the Kuiseb River. The Kuiseb also serves as a habitat and migration corridor for many animals, including the mountain zebra, leopard and ostrich.Based on the 2016 data, the research team created a model that calculated the fractional vegetation cover of the lower Kuiseb River based on raw reflectance values. By matching past satellite images for the previous 30 years to the present-day imagery, and then applying the same model, the team was able to estimate past and vegetation cover. "Essentially, the drone data worked as a bridge from the ground to what the satellite was seeing," explains co-author Jonathan Chipman , director of the Citrin Family GIS/Applied Spatial Analysis Laboratory at Dartmouth. "Our methods in the study provide a model for how ecologists can combine modern drone imagery and historic satellite data to reconstruct past environmental change."The results showed that one area of the Kuiseb River located between 110 and 140 kilometers upstream from the Atlantic Ocean in the terminal alluvial zone, which is typically dry but within the reach of floods and where soil sediments are deposited, not only had the highest vegetation but also had the most positive change in vegetation cover over the study period."Our findings demonstrate that vegetation cover in the lower Kuiseb River has been, on average, increasing for more than three decades," says Morgan. "As a result, we provide new insight into not only the long-term change in the hydrology and ecology of this system but also into how ephemeral rivers in desert landscapes might be responding to global change."The research team examined the climate and hydrological records to see if increased precipitation between 1984 and 2019 may explain the overall change in vegetation cover; however, the records did not show such steady increases in precipitation. According to the co-authors, the increase in vegetation cover may reflect a long-term recovery from the drought in the Namib Desert during the early 1980s, which could be investigated by using coarser-resolution satellite data prior to 1984. | Climate | 2,021 |
February 3, 2021 | https://www.sciencedaily.com/releases/2021/02/210203123449.htm | The Arctic Ocean was covered by a shelf ice and filled with freshwater | The Arctic Ocean was covered by up to 900 m thick shelf ice and was filled entirely with freshwater at least twice in the last 150,000 years. This surprising finding, reported in the latest issue of the journal | About 60,000 to 70,000 years ago, in a particularly cold part of the last glacial period, large parts of Northern Europe and North America were covered by ice sheets. The European ice sheet spanned a distance of more than 5000 kilometres, from Ireland and Scotland via Scandinavia to the Eastern rim of the Kara Sea (Arctic Ocean). In North America, large parts of what is now known as Canada were buried under two large ice sheets. Greenland and parts of the Bering Sea coastline were glaciated too. What was the ice situation like even further North, in the Arctic Ocean? Was it covered by thick sea-ice, or maybe with the tongues of these vast ice sheets were floating on it, far beyond the North Pole?Scientific answers to these questions were more or less hypothetical so far. In contrast to deposits on land, where erratic boulders, moraines and glacial valleys are the obvious landmarks of glaciers, only few traces of vast ice shelves had been found so far in the Arctic Ocean. Geoscientists from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) and MARUM Center for Marine Environmental Sciences at the University of Bremen have now compiled existing evidence from the Arctic Ocean and the Nordic Seas, and combined it with new data to arrive at a surprising conclusion.According to their study, the floating parts of the northern ice sheets covered large parts of the Arctic Ocean in the past 150,000 years. Once about 70,000-60,000 years ago and also about 150,000-130,000 years ago. In both periods, freshwater accumulated under the ice, creating a completely fresh Arctic Ocean for thousands of years."These results mean a real change to our understanding of the Arctic Ocean in glacial climates. To our knowledge, this is the first time that a complete freshening of the Arctic Ocean and the Nordic Seas has been considered -- happening not just once, but twice," says the first author, Dr Walter Geibert, geochemist at the Alfred Wegener Institute.Their finding is based on geological analyses of ten sediment cores from different parts of the Arctic Ocean, Fram Strait and the Nordic Seas. The stacked deposits mirror the climate history of the past glacials. When investigating and comparing the sediment records, the geoscientists found that an important indicator was missing, always in the same two intervals. "In saline sea water, the decay of naturally occurring uranium always results in the production of the isotope thorium-230. This substance accumulates at the sea floor, where it remains detectable for a very long time due to its half-life of 75,000 years," Walter Geibert explains.Therefore, geologists often use this thorium-isotope as a natural clock. "Here, its repeated and wide-spread absence is the giveaway that reveals to us what happened. According to our knowledge, the only reasonable explanation for this pattern is that the Arctic Ocean was filled with freshwater twice in its younger history- in frozen and liquid form," co-author and micropalaeontologist Dr Jutta Wollenburg, also from the AWI, explains.How can a large ocean basin, connected by several straits with the North Atlantic and the Pacific Ocean, turn entirely fresh? "Such a scenario is perceivable if we realize that in glacial periods, global sea levels were up to 130 m lower than today, and ice masses in the Arctic may have restricted ocean circulation even further," states co-author Professor Ruediger Stein, geologist at the AWI and the MARUM.Shallow connections like Bering Strait or the sounds of the Canadian Archipelago were above sea level at the time, cutting off the connection with the Pacific Ocean entirely. In the Nordic Seas, large icebergs or ice sheets extending onto the sea floor restricted the exchange of water masses. The flow of glaciers, ice melt in summer, and rivers draining into the Arctic Ocean kept delivering large amounts of fresh water to the system, at least 1200 cubic kilometres per year. A part of this amount would have been forced via the Nordic Seas through the sparse narrow deeper connections in the Greenland-Scotland Ridge into the North Atlantic, hindering saline water from penetrating further north. This resulted in the freshening of the Arctic Ocean."Once the mechanism of ice barriers failed, heavier saline water could fill the Arctic Ocean again," Walter Geibert says. "We believe that it could then quickly displace the lighter freshwater, resulting in a sudden discharge of the accumulated amount of freshwater over the shallow southern boundary of the Nordic Seas, the Greenland-Scotland-Ridge, into the North Atlantic."A concept that assumes that enormous amounts of freshwater were stored in the Arctic Ocean and available for rapid release would help understanding the connection between a range of past climate fluctuations. It would also offer an explanation for some apparent discrepancies between different ways of reconstructing past sea levels. "The remains of coral reefs have pointed to a somewhat higher sea level in certain cold periods than reconstructions from Antarctic ice cores, or reconstructions from the calcareous shells of small marine organisms, would suggest," explains Walter Geibert. "If we now accept that freshwater may not only have been stored in solid form on land, but some of it also in liquid form in the ocean, the different sea level reconstructions agree better and we can reconcile the location of the coral reefs with calculations of the freshwater budget."Freshwater release from the Arctic Ocean might also serve as an explanation for some abrupt climate change events during the last glacial period. During such events, temperatures in Greenland could rise by 8-10 degree centigrade within a few years, only returning to the original cold glacial temperatures over the course of hundreds or thousands of years. "We see an example here of a past Arctic climate tipping point of the Earth system. Now we need to investigate in more detail how these processes were interconnected, and evaluate how this new concept of the Arctic Ocean helps in closing further gaps in our knowledge, in particular in view of the risks of humanmade climate change," says Walter Geibert. | Climate | 2,021 |
February 3, 2021 | https://www.sciencedaily.com/releases/2021/02/210203123349.htm | Fish in warming Scottish seas grow faster but reach a smaller size | Researchers have found new evidence that global warming is affecting the size of commercial fish species, documenting for the first time that juvenile fish are getting bigger, as well as confirming that adult fish are getting smaller as sea temperatures rise. The findings are published in the British Ecological Society's | The researchers from the University of Aberdeen looked at four of the most important commercial fish species in the North Sea and the West of Scotland: cod, haddock, whiting and saithe. They found that juvenile fish in the North Sea and on the West of Scotland have been getting bigger while adult fish have been getting smaller. These changes in body size correlated with rising sea temperatures in both regions.Idongesit Ikpewe, lead author of the study, said: "Both the changes in juvenile and adult size coincided with increasing sea temperature. Importantly, we observed this pattern in both the North Sea, which has warmed rapidly, and the west of Scotland, which has only experienced moderate warming. These findings suggest that even a moderate rise in sea temperature may have an impact on commercial fish species' body sizes."In the short term, the findings may mean a reduction in commercial fishery yields, impacting an industry worth around £1.4 billion to the UK economy and one that employs over twenty-four thousand people, according to records from the House of Commons research library.Idongesit Ikpewe said "Our findings have crucial and immediate implications for the fisheries sector. The decrease in adult body size is likely to reduce commercial fisheries yields. However, in the long-term, the faster growing and larger juveniles may compensate, to some extent, for the latter yield loss, as although the increase in length (and, therefore, weight) per individual may be small, younger fish are far more numerous. It is this trade-off that we now need to investigate."To mitigate global warming effects and maximise sustainable yields, the authors say that temperature changes should be factored into forecasts used in fishery management.The findings are also likely to impact marine ecosystems. "Of the four species we looked at, three (cod, whiting and saithe) are fish eating predators towards the top end of the food chain and therefore have an important ecological role in the ecosystems they inhabit. Since predator size dictates what prey they can target, a change in the body size of these fish species may have implications or predator-prey relationships, with potential consequences on the structure of the food web." said Idongesit Ikpewe.The maximum body size fish can reach is determined by the supply and demand of limiting resources like oxygen. Warmer water typically contains less oxygen but also increases metabolic rates and therefore demand for oxygen. Fish in warming waters may sooner reach the size where they can no longer acquire the oxygen needed for maintaining metabolic demands, thereby limiting adult body size.It's previously been shown in laboratory experiments that ectotherms (cold-blooded animals) develop faster at warmer temperatures but reach a smaller body size. This phenomenon, termed the 'temperature size rule', has been observed in several different animals, plants and bacteria. However, until now, few empirical studies have shown a link between increased temperature and faster growth in fish.In this study the researchers examined the body size of cod, haddock, whiting and saithe at different age groups and compared trends in juvenile length and adult length with annual bottom sea temperatures.They obtained the data from International Bottom Trawl Surveys provided by the International Council for the Exploration of the Sea. This provided 30 years of fishery-independent bottom trawl data from 1970 to 2017 for the North Sea and 1986 to 2016 for the West of Scotland.Although the findings provide strong empirical evidence for changes in fish size and growth rate in warming seas, the study was limited to demersal species (living close to the seabed) in areas around the UK. Other commercially important species to the UK such as mackerel and herring were not considered in this study."The next stage of our work is to consider the management implications based on modelling these populations." said Idongesit Ikpewe. "The idea is to work out what the size changes we observed may mean for future fish productivity and yield under different scenarios of warming." | Climate | 2,021 |
February 3, 2021 | https://www.sciencedaily.com/releases/2021/02/210203090551.htm | Potentially toxic plankton algae may play a crucial role in the future Arctic | As the sea ice shrinks in the Arctic, the plankton community that produces food for the entire marine food chain is changing. New research shows that a potentially toxic species of plankton algae that lives both by doing photosynthesis and absorbing food may become an important player in the Arctic Ocean as the future sea ice becomes thinner and thinner. | Microscopic plankton algae, invisible to the naked eye, are the foundation of the marine food web, feeding all the ocean´s living creatures from small crustaceans to large whales. Plankton algae need light and nutrients to produce food by photosynthesis.A thick layer of sea ice -- sometimes covered with snow -- can reduce how much sunlight penetrates into the water and stop the algae getting enough light. However, as the sea ice is becoming thinner and less widespread in the Arctic, more and more light is penetrating into the sea. Does this mean more plankton algae and thus more food for more fish, whales and seabirds in the Arctic? The story is not so simple.More light in the sea will only lead to a higher production of plankton algae if they also have enough nutrients -- and this is often not the case. With the recent increase in freshwater melt from Arctic glaciers and the general freshening of the Arctic Ocean, more and more fresh and nutrient-depleted water is running out into the fjords and further out into the sea. The fresher water lies on top of the more salty ocean and stops nutrients from the deeper layers from mixing up towards the surface where there is light. And it is only here that plankton algae can be active.However, a brand new study published today in the journal Mixotrophic algae are small, single-celled plankton algae that can perform photosynthesis but also obtain energy by eating other algae and bacteria. This allows them to stay alive and grow even when their photosynthesis does not have enough light and nutrients in the water.In northeast Greenland, a team of researchers measured the production of plankton algae under the sea ice in the high-Arctic fjord Young Sound, located near Daneborg."We showed that the plankton algae under the sea ice actually produced up to half of the total annual plankton production in the fjord," says Dorte H. Søgaard from the Greenland Climate Research Centre, Greenland Institute of Natural Resources and the Arctic Research Centre, Aarhus University, who headed the study."Mixotrophic plankton algae have the advantage that they can sustain themselves by eating other algae and bacteria as a supplement to photosynthesis when there isn't enough light. This means that they are ready to perform photosynthesis even when very little light penetrates into the sea. In addition, many mixotrophic algae can live in relatively fresh water and at very low concentrations of nutrients -- conditions that often prevail in the water layers under the sea ice in the spring when the ice melts," Dorte H. Søgaard explains.For nine days, the researchers measured an algal bloom driven by mixotrophic algae occurring under the thick but melting sea ice in Young Sound during the Arctic spring in July, as the sun gained more power and more melt ponds spread across the sea ice, gradually letting through more light.The algae belong to a group called haptophytes. Many of these algae are toxic, and in this study they bloomed in quantities similar to those previously observed in the Skagerrak near southern Norway. Here, the toxic plankton algae killed large amounts of salmon in Norwegian fish farms."We know that haptophytes often appear in areas with low salinity -- as seen in the Baltic Sea, for example. It is therefore very probable that these mixotrophic-driven algae blooms will appear more frequently in a more freshwater-influenced future Arctic Ocean and that this shift in dominant algae to a mixotrophic algae species might have a large ecological and socio-economic impact." says Dorte H. Søgaard.The researchers behind the project point out that it is the first time that a bloom of mixotrophic algae has been recorded under the sea ice in the Arctic. | Climate | 2,021 |
February 2, 2021 | https://www.sciencedaily.com/releases/2021/02/210202164530.htm | Sea level will rise faster than previously thought, researchers show | There are two main elements to observe when assessing sea level rise. One is the loss of the ice on land, e.g., melting mountain glaciers and inland ice sheets on Greenland and Antarctica, and the other is that the sea will expand as it gets warmer. The more its temperature increases, the faster the sea will rise. Researchers at the Niels Bohr Institute, University of Copenhagen have constructed a new method of quantifying just how fast the sea will react to warming. The level of the sea is monitored meticulously, and we can compare the responsiveness in models with historical data. The comparison shows that former predictions of sea level have been too conservative, so the sea will likely rise more and faster than previously believed. The result is now published in the European Geosciences Union journal | During the last 150 years, in what is called the industrial period, sea levels have been rising, as Aslak Grinsted, associate professor at the Niels Bohr Institute research section, Physics of Ice, Climate and Earth, explains. "We expect, of course, that there is a connection between rising temperature and the rate indicating the momentum of the rise. Observations are telling us that the rate has been accelerating over the past 150 years. This means we can create a picture of how the connection between temperature and sea level rise has been, historically. But 150 years is not very long, actually, because of the great inertia in the warming of the oceans and inland ice sheets, so several hundreds of years can pass before we see the full consequences of warming in the atmosphere. This is why we compare the observations with the results from the detailed computer models we use to depict a future scenario. Among others, the climate panel of the United Nation's Intergovernmental Panel on Climate Change (IPCC), has gathered these projections, made from a collection of many smaller models. These, in turn, have been validated, obviously, as well as can be done."The predictions used by the IPCC are based on a jigsaw puzzle of models for ice sheets, glaciers and the warming of the sea. The predictions suffer, however, from the fact that only a limited amount of data are sometimes available for the models to be tested on. There was practically no data on the melt-off rate for Antarctica before we had coverage from satellite observations in the 1990s. "We have better historical data for the sea level rise in total, which, in principle, allows for a test of the combined puzzle of models. However, it has not been part of the routine to make sea level hindcasts at IPCC, so presently we are not able to tell if these models are capable of reproducing the historical sea level. At the Niels Bohr Institute, we have used this situation as our starting point, and so we observe how sensitive the models are in reacting to warming. We expect that if we compare observational data from the fairly short period of time from 1850 onwards with the sensitivity of the models, it should allow us to assess whether the models are realistic or not," Aslak Grinsted explainsThe research team at the Niels Bohr Institute is hoping their method for validating future scenarios by looking into the past can gain a foothold in how sea level rise will be analysed in the future. "Apparently, the models we are basing our predictions of sea level rise on presently are not sensitive enough. To put it plainly, they don't hit the mark when we compare them to the rate of sea level rise we see when comparing future scenarios with observations going back in time," Grinsted says."It is crucial for our faith in model based climate predictions that they are able to reproduce the realized climate as realistically as possible," Jens Hesselbjerg Christensen, Professor at the Ice, Climate and Geophysics Section at the Niels Bohr Institute and a co-author on the paper, adds. "We hope this new comparison metric will be adopted to as large extent as is possible and can become a tool we can apply in comparing different models. A good example is that we don't expect the sensitivity to be the same all the way back to the last millennium or several millions of years back in time, but the added understanding of how the sensitivity might change over time is something we can add to the comparisons between models and observations. Besides, we'd like to see the method applied to the individual processes contributing to sea level rise. This might make the understanding of the sensitivity even more detailed, we believe.""You could say," Aslak Grinsted ends the interview, " that this article has two main messages: The scenarios we see before us now regarding sea level rise are too conservative -- the sea looks, using our method, to rise more than what is believed using the present method. The other message is that research in this area can benefit from using our method to constrain sea level models in the scenarios in the future." | Climate | 2,021 |
February 2, 2021 | https://www.sciencedaily.com/releases/2021/02/210202164448.htm | Scientists advocate breaking laws -- of geography and ecology | Recent global calamities -- the pandemic, wildfires, floods -- are spurring interdisciplinary scientists to nudge aside the fashionable First Law of Geography that dictates "everything is related to everything else, but near things are more related than distant things." | Geography, and by association, ecology, has largely followed what's known as Tobler's Law, which took hold in the early 1970s. But then came the novel coronavirus apparently has leapt from wildlife meat markets in China to the world in a matter of months. Global climate change creates conditions ripe for infernos in the North American west and Australia. Extreme Ohio flooding in 2018 gave way to sediments and excessive nutrients to dump into the Gulf of Mexico to the tune of some 300 square kilometers.In other words, all that's local is a lot more global, and the scientists in this week's "Understanding and finding solutions to the recent and future crises need an integrated framework across local to global scales," said Jianguo "Jack" Liu, Michigan State University's (MSU) Rachel Carson Chair in Sustainability.Liu has introduced the framework of metacoupling, which allows scientists to view the world as it truly is -- with humans and nature interacting over space and time and without boundaries of academic disciplines. The metacoupling framework lets scientists understand how actions locally, nearby and far away -- like policies that regulate the sale of wild animals or affect the release of greenhouse gasses -- result more in just cause and effect. Actions bounce back and forth between humans and nature from the community nearby and the country on the other side of the world. These are examples of feedback, and there are impacts that spill over in between. The paper notes that the metacoupling inserts the human element into the equation -- both where events happen, and where our impact is felt, and the spaces in between.In other words, for much of environmental sciences, Tobler's Law and its geography focus is going the way of tube tops and tie-dye in favor of what the authors say is "a more comprehensive understanding of human-natural systems will emerge through this approach as a requisite for addressing today's large-scale ecological problems, and this will be part of the "evolution" of the new field of macrosystems biology."Lead author Flavia Tromboni says the paper delivers a message that science indeed must evolve to capture the world as it is -- and where it is going. "We cannot capture the magnitude of human impacts globally and be able to find solutions for pressing global environmental issues without considering all these multi-scale interactions," she said. Tromboni is a research assistant professor in the Global Water Center of the University of Nevada, Reno.Other authors of "Macrosystems as metacoupled human and natural systems" note the issues keep unfolding. Kyla Dahlin, an assistant professor in MSU's Department of Geography, Environment, and Spatial Sciences, points out today's western wildfires already are leading to questions about crops -- and ultimately grocery store prices -hundreds of miles away. "Metacoupling especially breaks with the idea of Tobler's Law," she said.The work is supported by the National Science Foundation and AgBioResearch. | Climate | 2,021 |
February 2, 2021 | https://www.sciencedaily.com/releases/2021/02/210202113828.htm | Study indicates US cities underestimate their GHG emissions by nearly 20% | Cities have become critical players in reducing the greenhouse gas (GHG) emissions that are causing global climate change. Urban areas produce almost 70 percent of those emissions, and city governments are proposing a variety of policy actions aimed at reducing them. Many cities also produce inventories that detail their greenhouse gas emissions. | Now, professor Kevin Gurney of Northern Arizona University's School of Informatics, Computing, and Cyber Systems and colleagues have compared the self-reported emissions inventories published by 48 major U.S. cities to estimates from a state-of-the-art emissions information system. As described in Gurney, who specializes in atmospheric science, ecology and climate policy, has spent the past two decades developing a standardized system for quantifying greenhouse gas emissions under his Vulcan and Hestia Projects. The system, funded by National Aeronautics and Space Administration (NASA) and the National Institute of Standards and Technology (NIST), quantifies and visualizes greenhouse gases emitted across the entire country down to individual power plants, neighborhoods and roadways.The emissions estimates generated by the system help identify problem areas and enable better decisions about where to cut emissions most effectively. Two recent studies, at the nationwide level (link) and within the city of Indianapolis, IN (link), have shown that Gurney's estimates are consistent with estimates based on direct atmospheric monitoring, a key independent form of independent validation.Climate change policies in cities are rapidly progressing, and cities often rely on their self-reported inventories when developing their policies, Gurney compared 48 of these self-reported inventories from U.S. cities to emissions estimated by his Vulcan information system. The cities in the study included New York, Chicago, Los Angeles, Dallas, Denver and Philadelphia."The results of this comparison were surprising," Gurney said. "The differences were large and varied widely from one city to the next. When averaged, the self-reported emissions were almost 20 percent below the emissions estimated by the Vulcan system." But that average doesn't tell the whole story: for example, Cleveland, Ohio reported emissions 90.1 percent below the Vulcan estimate while Palo Alto, Calif., reported emissions 41.7 percent greater than the Vulcan estimate.In order to prioritize and track emission reductions, cities will need an unbiased understanding of their emissions. "The adage 'you can't manage what you can't measure' is really applicable here," Gurney said. "Cities need a comprehensive and accurate assessment of their emissions. Without it, they could target the wrong emissions sources in their landscape for emission reduction or think they are on an emissions trajectory to meet their target, when in fact, they are not."For example, the city of Indianapolis aims to make a 20 percent reduction in GHG emissions from buildings by 2025 relative to 2016 values. With the 26.9 percent underestimate found in the study, it will be difficult to track progress towards this target or know when and if it has been achieved."Consistency in estimating emissions from one city to the next is also critical to comparing and contrasting different mitigation approaches and policies," said Gurney. "This allows cities to borrow emission mitigation policies from others with similar emission characteristics. The inconsistencies in self-reported inventories make that very difficult."The approach taken by the research team uses a consistent method across all cities in the U.S., combining federal, state, and local data systematically."It is expensive and time-consuming for cities to build accurate urban greenhouse gas inventories," said Geoffrey Roest, an NAU postdoctoral researcher and co-author of the study. "But we have emissions data for every city in the U.S., and we can collaborate with cities to help them produce comprehensive, accurate inventories from that data." The research team found that the differences between the self-reported inventories and the Vulcan estimates were likely due to cities' not accounting for particular fuels or sectors where local information was limited or difficult to come by."Vulcan data can be adapted to meet the needs of different cities by incorporating local data" said Yang Song, an NAU postdoctoral researcher and co-author on the study. "This will help cities identify the most effective strategies towards true and lasting emission reductions backed by the best science." | Climate | 2,021 |
February 2, 2021 | https://www.sciencedaily.com/releases/2021/02/210202113755.htm | What did the Swiss eat during the Bronze Age? | The Bronze Age (2200 to 800 BC) marked a decisive step in the technological and economic development of ancient societies. People living at the time faced a series of challenges: changes in the climate, the opening up of trade and a degree of population growth. How did they respond to changes in their diet, especially in Western Switzerland? A team from the University of Geneva (UNIGE), Switzerland, and Pompeu Fabra University (UPF) in Spain has for the first time carried out isotopic analyses on human and animal skeletons together with plant remains. The scientists discovered that manure use had become widespread over time to improve crop harvests in response to demographic growth. The researchers also found that there had been a radical change in dietary habits following the introduction of new cereals, such as millet. In fact, the spread of millet reflected the need to embrace new crops following the drought that ravaged Europe during this period. Finally, the team showed that the resources consumed were mainly terrestrial. The research results are published in the journal | Today, archaeological resources for studying the Bronze Age are limited. "This is partly down to changes in funeral rituals," begins Mireille David-Elbiali, an archaeologist in the Laboratory of Prehistoric Archaeology and Anthropology in the F.-A. Forel Department in UNIGE's Faculty of Sciences. "People gradually abandoned the inhumation practice in favour of cremation, thereby drastically reducing the bone material needed for research. And yet the Bronze Age signals the beginning of today's societies with the emergence of metallurgy." As the name suggests, societies began working with bronze, an alloy consisting of copper and tin. "And this development in metallurgy called for more intensive trade so they could obtain the essential raw materials. This increased the circulation of traditional crafts, prestigious goods, religious concepts and, of course, people between Europe and China," continues the archaeologist.The Neolithic Age marked the inception of animal husbandry and the cultivation of wheat and barley. But what about the diet in the next Bronze Age? Archaeobotany and archaeozoology have been routinely used to reconstruct the diet, environment, agricultural practices and animal husbandry in the Bronze Age, but these methods only provide general information. "For the first time, we decided to answer this question precisely by analysing human and animal skeletons directly. This meant we could study the stable isotopes from the collagen of the bones and teeth that constitute them and define their living conditions," continues Alessandra Varalli, a researcher in UPF's Department of Human Sciences and the study's first author. "In fact, we are what we eat," points out Marie Besse, a professor in the Laboratory of Prehistoric Archaeology and Anthropology in the F.-A. Forel Department at UNIGE. Biochemical analyses of bones and teeth will tell us what types of resources have been consumed." Forty-one human skeletons, 22 animal skeletons and 30 plant samples from sites in Western Switzerland and Haute-Savoie (France) were studied, ranging from the beginning to the end of the Bronze Age.The study's first outcome showed that there was no difference between the diets of men and women, and that there were no drastic changes in diet between childhood and the adult phase of these individuals. "So, there was no specific strategy for feeding children, just as men didn't eat more meat or dairy product than women. What's more, when it comes to the origin of the proteins consumed, it was found that although Western Switzerland is home to a lake and rivers, the diet was mainly based on terrestrial animals and plants to the exclusion of fish or other freshwater resources," adds Dr Varalli. But the main interest of the study lies in plants, which reveal societal upheavals."During the early Bronze Age (2200 to 1500 BC), agriculture was mainly based on barley and wheat, two cereals of Near Eastern origin that were grown from the Neolithic Age in Europe," explains Dr Varalli. "But from the late Late Bronze Age (1300 to 800 BC), we note that millet was introduced, a plant from Asia that grows in a more arid environmen." In addition, nitrogen isotopes revealed that manuring was used more intensively. "The analysis of several plant species from different phases of the Bronze Age suggests that there was an increase in soil fertilisation over time. This was most likely to boost the production of agricultural crops."These two discoveries combined seem to confirm the general aridity that prevailed in Europe during this period, which meant agriculture had to be adapted; and that there was heightened trade between different cultures, such as Northern Italy or the Danube region, leading to the introduction of millet into Western Switzerland. These new cereals might have played an important role in the security of supply, and perhaps contributed to the population increase observed in the Late Bronze Age. In fact, these cereals grow more quickly and are more resistant to drought, at a time when the climate was relatively warm and dry. Finally, the use of fertiliser went hand-in-hand with a general improvement in techniques, both agricultural and artisanal. "This first study on changes in diet in Western Switzerland during the Bronze Age corroborates what we know about the period. But it also demonstrates the richness of the widespread intercultural exchanges," states Professor Besse with enthusiasm. We still have much to learn about this millennium, in spite of the scientific problems related to the paucity of available material. "This is one of the reasons that led me to excavate the Eremita cave with UNIGE students. Located in the Piedmont region of Italy, it is dated to the Middle Bronze Age around 1600 BC," concludes Professor Besse. | Climate | 2,021 |
February 2, 2021 | https://www.sciencedaily.com/releases/2021/02/210202113725.htm | Novel photocatalyst effectively turns carbon dioxide into methane fuel with light | Carbon dioxide (CO | The research was led by Dr Ng Yun-hau, Associate Professor in the School of Energy and Environment (SEE), in collaboration with researchers from Australia, Malaysia and the United Kingdom. Their findings have been recently published in the scientific journal "Inspired by the photosynthesis in nature, carbon dioxide can now be converted effectively into methane fuel by our newly designed solar-powered catalyst, which will lower carbon emission. Furthermore, this new catalyst is made from copper-based materials, which is abundant and hence affordable," said Dr Ng.He explained that it is thermodynamically challenging to convert carbon dioxide into methane using a photocatalyst because the chemical reduction process involves a simultaneous transfer of eight electrons. Carbon monoxide, which is harmful to human, is more commonly produced in the process because it requires the transfer of two electrons only.He pointed out that cuprous oxide (Cu2O), a semiconducting material, has been applied as both photocatalyst and electrocatalyst to reduce carbon dioxide into other chemical products like carbon monoxide and methane in different studies. However, it faces several limitations in the reduction process, including its inferior stability and the non-selective reduction which causes the formation of an array of various products. Separation and purification of these products from the mixture can be highly challenging and this imposes technological barrier for large scale application. Furthermore, cuprous oxide can be easily corroded after brief illumination and evolve into metallic copper or copper oxide.To overcome these challenges, Dr Ng and his team synthesised a novel photocatalyst by enwrapping cuprous oxide with copper-based metal-organic frameworks (MOFs). Using this new catalyst, the team could manipulate the transfer of electrons and selectively produce pure methane gas.They discovered that when compared with cuprous oxide without MOF shell, cuprous oxide with MOF shell reduced carbon dioxide into methane stably under visible-light irradiation with an almost doubled yield. Also, cuprous oxide with MOF shell was more durable and the maximum carbon dioxide uptake was almost seven times of the bare cuprous oxide.The team encapsulated the one-dimensional (1-D) cuprous oxide nanowires (with a diameter of about 400nm) with the copper-based MOF outer shell of about 300nm in thickness. This conformal coating of MOF on cuprous oxide would not block light-harvesting of the catalyst. Besides, MOF is a good carbon dioxide adsorbent. It provided considerable surface areas for carbon dioxide adsorption and reduction. As it was closely attached to the cuprous oxide, it brought a higher concentration of carbon dioxide adsorbed at locations near the catalytic active sites, strengthening the interaction between carbon dioxide and the catalyst.Moreover, the team discovered that the cuprous oxide was stabilised by the conformal coating of MOF. The excited charges in cuprous oxide upon illumination could efficiently migrate to the MOF. In this way, excessive accumulation of excited charges within the catalyst which could lead to self-corrosion was avoided, hence extended the catalyst's lifetime.Previously, it was generally believed that the improved photocatalytic activities were merely induced by MOF's reactant concentration effect and MOF only served as a reactant adsorbent. However, Dr Ng's team unveiled how the excited charges migrate between cuprous oxide and MOF in this research. "MOF is proven to play a more significant role in shaping the reaction mechanism as it changes the electron pathway," he said. He pointed out that this discovery has extended the understanding of relationships between MOFs and metal oxides beyond their conventional physical/chemical adsorption type of interactions to facilitating charge separation.The team has spent more than two years to develop this effective strategy in converting carbon dioxide. Their next step will be to further increase the methane production rate and explore ways to scale up both the synthesis of the catalyst and the reactor systems. "In the entire process of converting carbon dioxide to methane, the only energy input we have used was sunlight. We hope in the future, carbon dioxide emitted from factories and transportation can be 'recycled' to produce green fuels," concluded Dr Ng. | Climate | 2,021 |
February 2, 2021 | https://www.sciencedaily.com/releases/2021/02/210202164528.htm | Arctic shrubs add new piece to ecological puzzle | A 15-year experiment on Arctic shrubs in Greenland lends new understanding to an enduring ecological puzzle: How do species with similar needs and life histories occur together at large scales while excluding each other at small scales? The answer to this question has important implications for how climate change might shift species' distributions across the globe. | The study was published today in the journal Like lines of traffic traveling the same roads at the same time without crashing into each other, dwarf birch and gray willow dominate the Arctic landscape, covering and overlapping the same expansive territory, yet excluding each other in nearly indistinguishable microhabitats.The study suggests that climate and species interactions work together to promote the shrubs at large scales while also promoting their exclusion at small scales. In this case, herbivory by caribou and muskoxen tips the balance in favor of one species or another at small scales but favors their co-occurrence at large scales.This question of species diversity and co-occurrence versus exclusion has roots in a seminal paper in 1958 by Robert H. MacArthur that is taught in community ecology classes across the world. In that study, five species of warblers in the northeastern United States were observed avoiding each other while making their livings on different parts of the same tree -- some preferring upper or middle branches, others the ground or trunk, for example."This is one of the most readily observable phenomena in nature," said lead author Eric Post, director of the UC Davis Polar Forum and a professor in the Department of Wildlife, Fish and Conservation Biology. "Yet what influences species co-variation at both scales is something ecologists have argued about for decades. Our study shows that the same factors can act at both large and small scales with opposite effects on co-occurrence and exclusion. It's fascinating."For the study, the authors conducted the 15-year experiment at Post's long-time field site in Greenland. There, they recorded how arctic shrub abundance and composition changed in response to experimental warming treatments and to a treatment that fenced off large sections of tundra to exclude herbivores, such as caribou and muskoxen.The experiment confirmed what recent theoretical work has suggested: physical conditions, such as climate, combine with species interactions to shape opposing patterns of variation among arctic shrubs at large and local scales.The Arctic is becoming warmer and, in many places, drier. Those conditions favor willow over dwarf birch, the study found, even though birch are more abundant at the study site. While the absence of large herbivores favors almost complete exclusion of willow by birch, warming under those conditions swings the pendulum back slightly in favor of willow. Work in progress at the site also indicates changes in numbers of caribou and muskoxen, suggesting that muskoxen may be driving the balance between willows and birch under warming.How willow and birch react to such changes will affect how much carbon can be stored. The more shrubs in the Arctic, the more carbon is absorbed from the atmosphere. A diversity of species across the tundra provides a more efficient carbon sponge that just one dominant species of shrub."Woody shrubs are expanding across many, but not all, regions of the treeless arctic tundra in what's referred to as 'arctic greening,'" Post said. "We're witnessing the transformation of a sensitive biome right beneath our feet."This work suggests that large herbivores can interact with warming-driven shrub expansion in complex ways, potentially shaping the carbon landscape.The study's co-authors include Sean Cahoon of the USDA Forest Service in Alaska, Jeffrey Kerby of Aarhus University in Denmark, Christian Pedersen of the Norwegian Institute of Bioeconomy Research, and Patrick Sullivan of the University of Alaska in Anchorage.The study was funded by the National Geographic Society, NASA and the U.S. National Science Foundation. | Climate | 2,021 |
February 1, 2021 | https://www.sciencedaily.com/releases/2021/02/210201155455.htm | Geologists produce new timeline of Earth's Paleozoic climate changes | The temperature of a planet is linked with the diversity of life that it can support. MIT geologists have now reconstructed a timeline of the Earth's temperature during the early Paleozoic era, between 510 and 440 million years ago -- a pivotal period when animals became abundant in a previously microbe-dominated world. | In a study appearing today in the The new record, more detailed than previous timelines of this period, is based on the team's analysis of carbonate muds -- a common type of limestone that forms from carbonate-rich sediments deposited on the seafloor and compacted over hundreds of millions of years."Now that we have shown you can use these carbonate muds as climate records, that opens the door to looking back at this whole other part of Earth's history where there are no fossils, when people don't really know much about what the climate was," says lead author Sam Goldberg, a graduate student in MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS).Goldberg's co-authors are Kristin Bergmann, the D. Reid Weedon, Jr. Career Development Professor in EAPS, along with Theodore Present of Caltech and Seth Finnegan of the University of California at Berkeley.To estimate Earth's temperature many millions of years ago, scientists analyze fossils, in particular, remains of ancient shelled organisms that precipitated from seawater and either grew on or sank to the seafloor. When precipitation occurs, the temperature of the surrounding water can change the composition of the shells, altering the relative abundances of two isotopes of oxygen: oxygen-16, and oxygen-18."As an example, if carbonate precipitates at 4 degrees Celsius, more oxygen-18 ends up in the mineral, from the same starting composition of water, [compared to] carbonate precipitating at 30 degrees Celsius," Bergmann explains. "So, the ratio of oxygen-18 to -16 increases as temperature cools."In this way, scientists have used ancient carbonate shells to backtrack the temperature of the surrounding seawater -- an indicator of the Earth's overall climate -- at the time the shells first precipitated. But this approach has taken scientists only so far, up until the earliest fossils."There is about 4 billion years of Earth history where there were no shells, and so shells only give us the last chapter," Goldberg says.The same precipitating reaction in shells also occurs in carbonate mud. But geologists assumed the isotope balance in carbonate muds would be more vulnerable to chemical changes."People have often overlooked mud. They thought that if you try to use it as a temperature indicator, you might be looking at not the original ocean temperature in which it formed, but the temperature of a process that occurred later on, when the mud was buried a mile below the surface," Goldberg says.To see whether carbonate muds might preserve signatures of their original surrounding temperature, the team used "clumped isotope geochemistry," a technique used in Bergmann's lab, which analyzes sediments for clumping, or pairing, of two heavy isotopes: oxygen-18 and carbon-13. The likelihood of these isotopes pairing up in carbonate muds depends on temperature but is unaffected by the ocean chemistry in which the muds form.Combining this analysis with traditional oxygen isotope measurements provides additional constraints on the conditions experienced by a sample between its original formation and the present. The team reasoned that this analysis could be a good indication of whether carbonate muds remained unchanged in composition since their formation. By extension, this could mean the oxygen-18 to -16 ratio in some muds accurately represents the original temperature at which the rocks formed, enabling their use as a climate record.The researchers tested their idea on samples of carbonate muds that they extracted from two sites, one in Svalbard, an archipelago in the Arctic Ocean, and the other in western Newfoundland. Both sites are known for their exposed rocks that date back to the early Paleozoic era.In 2016 and 2017, teams traveled first to Svalbard, then Newfoundland, to collect samples of carbonate muds from layers of deposited sediment spanning a period of 70 million years, from the mid-Cambrian, when animals began to flourish on Earth, through the Ordovician periods of the Paleozoic era.When they analyzed the samples for clumped isotopes, they found that many of the rocks had experienced little chemical change since their formation. They used this result to compile the rocks' oxygen isotope ratios from 10 different early Paleozoic sites to calculate the temperatures at which the rocks formed. The temperatures calculated from most of these sites were similar to previously published lower-resolution fossil temperature records. In the end, they mapped a timeline of temperature during the early Paleozoic and compared this with the fossil record from that period, to show that temperature had a big effect on the diversity of life on the planet."We found that when it was warmer at the end of the Cambrian and early Ordovician, there was also a peak in microbial abundance," Goldberg says. "From there it cooled off going into the middle to late Ordovician, when we see abundant animal fossils, before a substantial ice age ends the Ordovician. Previously people could only observe general trends using fossils. Because we used a material that's very abundant, we could create a higher-resolution record and could see more clearly defined ups and downs."The team is now looking to analyze older muds, dating back before the appearance of animals, to gauge the Earth's temperature changes prior to 540 million years ago."To go back beyond 540 million years ago, we have to grapple with carbonate muds, because they are really one of the few records we have to constrain climate in the distant past," Bergmann says.This research was supported, in part, by NASA and the David and Lucile Packard Foundation. | Climate | 2,021 |
February 1, 2021 | https://www.sciencedaily.com/releases/2021/02/210201155449.htm | Newly discovered trait helps plants grow deeper roots in dry, compacted soils | A previously unknown root trait allows some cereal plants to grow deeper roots capable of punching through dry, hard, compacted soils, according to Penn State researchers, who suggest that harnessing the inherited characteristic could lead to crops better able to deal with a changing climate. | "This discovery bodes well for American and global agriculture because the trait helps corn, wheat and barley grow deeper roots, which is important for drought tolerance, nitrogen efficiency and carbon sequestration," said Jonathan Lynch, distinguished professor in plant science. "Breeding for this trait should be helpful in developing new crops for climate mitigation."Called multiseriate cortical sclerenchyma by the researchers -- or MCS -- the phenotype is characterized by small cells with thick walls just beneath the surface of the roots. Roots with the MCS genotype have a greater concentration of lignin -- a complex organic polymer that is important in the formation of cell walls, especially in wood and bark, that lends rigidity.More lignin gives the MCS roots greater tensile strength and greater root tip bending force compared to non-MCS genotypes. This added rigidity helps roots penetrate hard soil layers.The findings of the root anatomy study, published today (Feb. 1) in Soil compaction reduces porosity, limits water infiltration, reduces aeration and restricts root growth by presenting a physical impediment, noted lead researcher Hannah Schneider, postdoctoral scholar in Lynch's research group in the College of Agricultural Sciences."Compacted soil layers constrain crop productivity by restricting root growth and exploration in deeper soil layers, which in turn limits access to nutrients and water," she said. "Plants with roots that are able to penetrate hard soil and forage deeper have an advantage in capturing water and nutrients -- ultimately performing better in drought or low soil fertility."The study included both field and greenhouse components to assess root-penetration ability in compacted soils.Scientists conducted two field experiments to study root growth -- one at the Apache Root Biology Center in Willcox, Arizona, and the other at Penn State's Russell E. Larson Agricultural Research Center at Rock Springs. At each location, researchers grew six corn genotypes contrasting in root lignin content. Each field experiment involved compaction and noncompaction treatments.When the corn flowered, soils were cored near randomly selected plants to assess root growth. The roots of two plants per research plot also were dug up and evaluated, and shoot biomass was collected.Twelve wheat genotypes and six corn genotypes also were grown in a greenhouse at the University Park campus. Large growth containers, or "mesocosms," were set up with a compacted soil layer to determine which roots penetrated the hard substrate. After more than a month's growth, root segments from each of the corn and wheat genotypes were collected, measured and tested for tensile strength and root tip bending force.This research utilized laser ablation tomography -- known as LAT -- to visualize the anatomy of roots from plants in the study. Lynch's research group developed the unique technology in 2011 for other root-analysis applications. Researchers using LAT can measure the light spectra given off by different cells cut by the laser to differentiate between various tissues.Genetic variation for MCS was found in each of the cereals examined by the researchers, and heritability was relatively high, they reported, suggesting that this trait can be selected in breeding programs. Of the plant lines reviewed in this study, MCS was present in 30 to 50% of modern corn, wheat and barley cultivars.The implications of corn crops growing deeper roots to range farther for water and nutrients -- and as a consequence producing larger yields -- would be immense in regions where the populace is food-insecure, Schneider pointed out. That is especially true in the face of a changing climate that is making vast areas more drought-prone."We observe MCS in corn, wheat, barley and many other cereal crops, and our work suggests that many of the benefits of MCS may be analogous across different species," she said. "MCS could be an important trait for stress tolerance and increased yields in cereal crops." | Climate | 2,021 |
February 1, 2021 | https://www.sciencedaily.com/releases/2021/02/210201144914.htm | Summer weather conditions influence winter survival of honey bees | Winter survival of honey bee colonies is strongly influenced by summer temperatures and precipitation in the prior year, according to Penn State researchers, who said their findings suggest that honey bees have a "goldilocks" preferred range of summer conditions outside of which their probability of surviving the winter falls. | The results of this study, which used several years of survey data provided by the Pennsylvania State Beekeeper's Association and its members, enabled the development of a tool for forecasting honey bee winter survival to support beekeepers' management decisions, the researchers said.Honey bees contribute more than $20 billion in pollination services to agriculture in the United States and generate another $300 million annually in honey production for U.S. beekeepers, noted the study's lead author, Martina Calovi, postdoctoral researcher in the Earth and Environmental Systems Institute in the College of Earth and Mineral Sciences."However, winter colony mortality greatly reduces the economic and ecosystem contributions of honey bees, which suffered estimated overwintering mortality rates of more than 53% from 2016 to 2019 in the United States," Calovi said. "Although winter mortality is known to vary regionally, the landscape and weather factors underlying this variation are poorly understood."Honey bee colonies are not dormant during the winter, Calovi pointed out. The bees remain active and maintain the hive temperature between 75 and 93 degrees Fahrenheit by forming a thermoregulating cluster, in which they organize into a tight ball and vibrate their flight muscles to generate heat, allowing the colony to survive when outside temperatures fall below 50 F. This enables them to survive long periods of cold temperatures."During the winter, the colony stops foraging for nectar and pollen and relies on its existing food stores, collected during the plant growing season," she said. "Rearing of new bees also ceases, and the colony depends on the survival of a long-lived cohort of bees that is produced in the autumn."As a result, any factors that limit the colony's ability to store adequate amounts of food during the summer and fall, that undermine effective thermoregulation during the winter, or that reduce the life span of overwintering bees can contribute to colony mortality, said co-author Christina Grozinger, Publius Vergilius Maro Professor of Entomology in the College of Agricultural Sciences.Among these factors, she said, are weather conditions that influence the availability of forage, the bees' ability to thermoregulate in the winter, and the amount of time before bees are able to initiate brood rearing in the spring. Other dynamics include beekeeper management practices that affect parasite and pathogen loads -- particularly control of Varroa mites that transmit viruses -- and forage quality and pesticide exposure due to the surrounding land use."We need to consider all of these factors when modeling and predicting honey bee winter survival," Grozinger said, "and that requires large data sets that span multiple types of habitats, microclimates and years."To collect beekeeper management and winter survival data, the researchers collaborated with the Pennsylvania State Beekeepers Association, which conducts an annual winter-loss survey of beekeepers across the state. The association provided data from this survey covering three winters and containing information about 1,429 honey bee colonies within 257 apiaries.For each reported apiary location, the researchers compiled data on weather and topographic variables that determine temperature and moisture conditions, as well as landscape variables that influence the availability of floral resources and insecticide exposure risk. The team included agronomic measures such as consecutive dry days and growing degree days, which is a measure of heat accumulation used to estimate growth and development of plants and insects during the growing season.These diverse and complex datasets were integrated and analyzed using Random Forest, a machine learning algorithm that merges the output of multiple variables to reach a single result.As the research team reported recently in For these beekeepers, the four most important variables in predicting winter colony survival were growing degree days, maximum temperature of the warmest quarter, precipitation during the warmest quarter and precipitation during the wettest quarter. Of these, the strongest predictor was growing degree days in the prior summer, which researchers said may relate to floral resource availability."The importance of weather conditions in predicting winter bee survival is quite clear from our analysis," said co-author Sarah Goslee, ecologist with the Pasture Systems and Watershed Management Research Unit of the U.S. Department of Agriculture's Agricultural Research Service."Our nuanced analysis of 36 weather and other environmental variables found adverse effects of both too-cool and too-hot summers," she said. "This model can be used to predict the probability of overwintering success, both for the current year and in projected future climate change scenarios."The model was used to develop a real-time tool to predict honey bee survival probability as a function of growing degree days, said Grozinger, who is director of Penn State's Center for Pollinator Research. The tool, "BeeWinterWise," has been incorporated into Beescape, a decision support system spearheaded by the center that is used by beekeepers and technical advisors."We believe this is the first study on honey bee overwintering survival that combines weather, topography and land-use factors," said Calovi. "Our results demonstrate both the predictive power of weather variables on honey bee overwintering survival, and the value of addressing this type of question with machine learning methods." | Climate | 2,021 |
February 1, 2021 | https://www.sciencedaily.com/releases/2021/02/210201115945.htm | Antarctica's ice melt isn't consistent, new analysis shows | Antarctic ice is melting, contributing massive amounts of water to the world's seas and causing them to rise -- but that melt is not as linear and consistent as scientists previously thought, a new analysis of 20 years' worth of satellite data indicates. | The analysis, built on gravitational field data from a NASA satellite system, shows that Antarctica's ice melts at different rates each year, meaning the models scientists use to predict coming sea level rise might also need adjusting."The ice sheet is not changing with a constant rate -- it's more complicated than a linear change," said Lei Wang, assistant professor of civil, environmental and geodetic engineering at The Ohio State University and lead author of the analysis. "The change is more dynamic: The velocity of the melt changes depending on the time."The research was published in The researchers' analysis is built on data from NASA's GRACE (Gravity Recovery and Climate Experiment), a two-satellite mission that measures changes in the world's oceans, ground water and ice sheets.Models that predict sea-level rise are typically built around the assumption that ice is melting from the world's largest ice fields in Antarctica and Greenland at a consistent rate.But this analysis found that, because the mass of ice on the Antarctic Ice Sheet changes depending on the season and year, those projections are not as reliable as they could be. Extreme snowfall one year, for example, might increase the amount of ice in Antarctica. Changes in the atmosphere or surrounding ocean might decrease it another year.Overall, Wang said, the volume of ice in Antarctica is decreasing. But a chart of the decline on a line graph would have spikes and valleys depending on what happened in a given time period.To understand those changes, Wang and the other researchers evaluated data on the gravitational field between the satellites over Antarctica and ice on the continent. Changes to the ice's mass -- either increases from big snowfalls or decreases from melt -- change that gravitational field.From 2016 to 2018, for example, the ice sheet in West Antarctica actually grew a bit because of a massive snow. During that same time period, though, the ice sheet in East Antarctica shrank because of melt."I'm not saying Antarctica's ice melt is not an acute problem -- it is still very acute," Wang said. "All of Antarctica is losing mass, very rapidly. It's just a time scale problem and a rate problem, and our models that predict sea-level change should reflect that." | Climate | 2,021 |
February 1, 2021 | https://www.sciencedaily.com/releases/2021/02/210201090829.htm | Research catches up to world's fastest-growing plant | <em>Wolffia</em> | A multi-investigator effort led by scientists from the Salk Institute is reporting new findings about the plant's genome that explain how it's able to grow so fast. The research, published in the February 2021 issue of "A lot of advancement in science has been made thanks to organisms that are really simple, like yeast, bacteria and worms," says Todd Michael, first author of the paper and a research professor in Salk's Plant Molecular and Cellular Biology Laboratory. "The idea here is that we can use an absolutely minimal plant like To understand what adaptations in "Surprisingly, The researchers also found that genes associated with other important elements of behavior in plants, such as defense mechanisms and root growth, are not present. "This plant has shed most of the genes that it doesn't need," Michael adds. "It seems to have evolved to focus only on uncontrolled, fast growth.""Data about the One focus of Michael's lab is learning how to develop new plants from the ground up, so that they can be optimized for certain behaviors. The current study expands knowledge of basic plant biology as well as offers the potential for improving crops and agriculture. By making plants better able to store carbon from the atmosphere in their roots, an approach pioneered by Salk's Harnessing Plants Initiative, scientists can optimize plants to help address the threat of climate change.Michael plans to continue studying | Climate | 2,021 |
February 1, 2021 | https://www.sciencedaily.com/releases/2021/02/210201093242.htm | Wellbeing benefits of wetlands | Australians love their beaches, and now a new study also confirms the broad appeal of other coastal assets such as tidal wetlands, nature trails and protected areas including bird and dolphin sanctuaries. | In one of the first studies of its kind in Australia, ahead of World Wetlands Day (2 February), Flinders University environment and marine ecology experts have conducted an Adelaide-based survey of how residents connect with and rate the attributes of Adelaide's northern metropolitan coastal wetlands.The findings, just published in the journal "People who visited the study region for recreation and work identified a personal bond with the places like Adelaide's Dolphin Sanctuary, the International Bird Sanctuary and St Kilda Mangrove Trail and other coastal national parks and coastal features situated so close to the city -- added reasons to take good care of these precious resources," says lead author, Flinders University geographer Associate Professor Beverley Clarke.The study used a 'cultural ecosystem services' framework to assess residents' perceptions about the benefits they gained from these wetlands."Translating the benefits people receive from coastal ecosystems in a way that is usable to policy-makers and environmental managers is important but challenging," says Associate Professor Clarke."Here we have been able to document health and wellbeing benefits expressed by the people who experience these places. As well as simply appreciating the natural landscape, it is through their activities that citizens developed an attachment to the coastline."People value these places as they become familiar with them," say Associate Professor Clarke, a life member of the Australian Coastal Society, who researches coastal planning and management with a current focus on strategies to support adaptation and resilience of coastal communities to the impacts of climate change.Co-author marine biologist, Professor Sabine Dittmann, an expert in coastal ecosystem ecology and blue carbon at Flinders University's College of Science and Engineering, says this social values survey highlights the co-benefits of coastal restoration."Naturalness of coastal wetlands matters most to people and will be an important outcome from restoring tidal wetlands, in addition to carbon sequestration gains," she says.Professor Dittmann is involved in carbon sequestration and saltmarsh restoration projects at Dry Creek north of Adelaide.Irrespective of their socio-ecological and climatic importance, coastal wetlands around the world are among the most threatened of all environments, facing human-induced pressures of landscape modification for agriculture and urbanisation, and climate-induced sea level rises.The researchers note that building awareness of the social benefits of restoring these sometimes under-appreciated wetlands may help generate support for protecting -- rather than developing -- these threatened landscapes. | Climate | 2,021 |
January 29, 2021 | https://www.sciencedaily.com/releases/2021/01/210129110942.htm | Arctic warming and diminishing sea ice are influencing the atmosphere | The researchers of the Institute for Atmospheric and Earth system research at the University of Helsinki have investigated how atmospheric particles are formed in the Arctic. Until recent studies, the molecular processes of particle formation in the high Arctic remained a mystery. | During their expeditions to the Arctic, the scientists collected measurements for 12 months in total. The results of the extensive research project were recently published in the The researchers discovered that atmospheric vapors, particles, and cloud formation have clear differences within various Arctic environments. The study clarifies how Arctic warming and sea ice loss strengthens processes where different vapors are emitted to the atmosphere. The thinning of sea ice enables more iodine emissions while broader open waters enable more emissions of sulfur-containing vapors.Higher concentrations of vapors result in a higher amount of particles. This on the other hand will lead to more clouds, which can -- depending on the season and location -- either slow down or accelerate the Arctic warming. Detailed knowledge of these processes is crucial in order to understand the consequences of global warming."Our observations are contributing to further understanding of what happens in the Arctic atmosphere due to warming. In general, atmospheric particles and clouds play an important role in regulating the atmosphere's temperature, and any changing behavior of these has consequences on Arctic warming. Arctic areas are especially sensitive to changes in cloudiness and albedo," says Lisa Beck, a doctoral student at the Institute for Atmospheric and Earth System Research (INAR).The researchers conducted measurements in Northern Greenland at Villum research station and in Svalbard at Ny-Ålesund for 6-months at each station. While both sites are located at similar latitudes, about 1000 km south of the North Pole, their environments are very different. Villum-station is surrounded by sea ice all year round, while the warm sea currents cause the sea around Ny-Ålesund to remain open.In Northern Greenland the researchers discovered that in the spring after the Polar night the microalgae below the sea ice started to emit iodine compounds to the atmosphere. As the spring continues, the thinning sea ice leads to the emission of even more iodine compounds. These compounds form molecular clusters that can grow into bigger particles.In Svalbard, surrounded by open waters, the observations showed how sulfur-compounds emitted by phytoplankton could form a large amount of particles that could grow fast, and can even form cloud droplets. In the studies of Svalbard also organic compounds were detected.The large amount and role of organic compounds in the Arctic particle formation surprised the researchers."We did not expect to observe many organic vapors in the cold and bare Arctic environment as they have been mainly seen in areas covered by forests. We are planning to continue the studies in Svalbard to figure out what these organic compounds are and where they are coming from," Beck says.The particle concentrations in Svalbard were clearly higher than the ones measured in Northern-Greenland."Currently, the Arctic sea ice is melting fast. As a result, we can assume that the processes observed in Svalbard will be more common in the Arctic areas that will be liberated from sea ice," Beck says.The published research is connected to the recent Polarstern studies that have continued the studies in the high Arctic in the middle of sea ice areas. | Climate | 2,021 |
January 29, 2021 | https://www.sciencedaily.com/releases/2021/01/210129110934.htm | Past river activity in northern Africa reveals multiple Sahara greenings | Large parts of today's Sahara Desert were green thousands of years ago. Prehistoric engravings of giraffes and crocodiles testify to this, as does a stone-age cave painting in the desert that even shows swimming humans. However, these illustrations only provide a rough picture of the living conditions. Recently, more detailed insights have been gained from sediment cores extracted from the Mediterranean Sea off the coast of Libya. An international research team examined these cores and discovered that the layers of the seafloor tell the story of major environmental changes in North Africa over the past 160,000 years. Cécile Blanchet of the German Research Centre for Geosciences GFZ and her colleagues from Germany, South Korea, the Netherlands and the USA report on this in the journal | Together with the GEOMAR Helmholtz Centre for Ocean Research Kiel, a team of scientists organized a research cruise on the Dutch vessel Pelagia to the Gulf of Sirte in December 2011. "We suspected that when the Sahara Desert was green, the rivers that are presently dry would have been active and would have brought particles into the Gulf of Sirte," says lead author Cécile Blanchet. Such sediments would help to better understand the timing and circumstances for the reactivation of these rivers.Using a method called "piston coring," the scientists were able to recover 10-meters long columns of marine mud. "One can imagine a giant hollow cylinder being pushed into the seafloor," says co-author Anne Osborne from GEOMAR, who was onboard the research ship. "The marine mud layers contain rock fragments and plant remains transported from the nearby African continent. They are also full of shells of microorganisms that grew in seawater. Together, these sediment particles can tell us the story of past climatic changes," explains Blanchet."By combining the sediment analyses with results from our computer simulation, we can now precisely understand the climatic processes at work to explain the drastic changes in North African environments over the past 160,000 years," adds co-author Tobias Friedrich from the University of Hawai'i.From previous work, it was already known that several rivers episodically flowed across the region, which today is one of the driest areas on Earth. The team's unprecedented reconstruction continuously covers the last 160,000 years. It offers a comprehensive picture of when and why there was sufficient rainfall in the Central Sahara to reactivate these rivers. "We found that it is the slight changes in the Earth's orbit and the waxing and waning of polar ice sheets that paced the alternation of humid phases with high precipitation and long periods of almost complete aridity," explains Blanchet.The fertile periods generally lasted five thousand years and humidity spread over North Africa up to the Mediterranean coast. For the people of that time, this resulted in drastic changes in living conditions, which probably led to large migratory movements in North Africa. "With our work we have added some essential jigsaw pieces to the picture of past Saharan landscape changes that help to better understand human evolution and migration history," says Blanchet. "The combination of sediment data with computer-simulation results was crucial to understand what controlled the past succession of humid and arid phases in North Africa. This is particularly important because it is expected that this region will experience intense droughts as a consequence of human-induced climate change." | Climate | 2,021 |
January 29, 2021 | https://www.sciencedaily.com/releases/2021/01/210129105054.htm | Hurricanes and typhoons moving 30km closer to coasts every decade | High-intensity tropical cyclones have been moving closer to coasts over the past 40 years, potentially causing more destruction than before. | The trend of tropical cyclones -- commonly known as hurricanes or typhoons -- increasingly moving towards coasts over the past 40 years appears to be driven by a westward shift in their tracks, say the study's authors from Imperial College London.While the underlying mechanisms are not clear, the team say it could be connected to changes in tropical atmospheric patterns possibly caused by climate change. The research is published today in Globally, 80 to 100 cyclones develop over tropical oceans each year, impacting regions in the Pacific, Atlantic and Indian Oceans and causing billions of dollars of damage.Lead author Dr Shuai Wang, from the Department of Physics at Imperial, said: "Tropical cyclones are some of the most devastating natural hazards in terms of how destructive and frequent they are in coastal regions."Our study shows they are likely becoming more destructive as they spend more time along coastlines at their highest intensities. The risk to some coastal communities around the world may be increasing and that will have profound implications over the coming decades."The team analysed global data from 1982-2018 on tropical cyclone formation, movement and intensity mainly gathered from satellite observations. They found that at maximum intensity, cyclones were on average getting 30km closer to coastlines per decade. There were also on average two more cyclones per decade within 200km of land.These increases did not necessarily mean more cyclones made landfall (reached land). However, the 'near-misses' or 'indirect-hit' cyclones near coasts can still cause damage, such as Hurricane Sandy in 2012 and Hurricane Dorian in 2019, both of which skirted along the US coast for a considerable time before making landfall.The paper's other author, Professor Ralf Toumi from the Department of Physics and Co-Director of the Grantham Institute -- Climate Change and Environment at Imperial, said: "We need to understand all aspects of tropical cyclones and this new study shows how their locations are changing. This often gets less attention than changes in their intensity but is at least as important."Previously, studies have shown that the maximum intensity of tropical cyclones is found further towards the poles. However, this does not necessarily mean these more poleward storms are more devastating. The new findings show cyclones at maximum intensity are also migrating westward, bringing them closer to coastlines and increasing their potential for damage.The westward migration appears to be driven by anomalous 'steering' -- the underlying flow in the atmosphere that carries cyclones along their tracks. The exact mechanism for this enhanced westward steering is unknown, but it may be due to the same underlying mechanism for poleward migration of cyclones as rising temperatures cause atmospheric patterns to shift.The team will next use climate simulations to determine the underlying mechanism behind these historical shifts and project potential future shifts in tropical cyclone tracks towards global coastal regions. | Climate | 2,021 |
January 29, 2021 | https://www.sciencedaily.com/releases/2021/01/210129090526.htm | Forty years of coral spawning captured in one place for the first time | Efforts to understand when corals reproduce have been given a boost thanks to a new resource that gives scientists open access to more than forty years' worth of information about coral spawning. | Led by researchers at Newcastle University, UK, and James Cook University, Australia, the Coral Spawning Database (CSD) for the first time collates vital information about the timing and geographical variation of coral spawning. This was a huge international effort that includes over 90 authors from 60 institutions in 20 countries.The data can be used by scientists and conservationists to better understand the environmental cues that influence when coral species spawn, such as temperature, daylight patterns and the lunar cycle.By providing access to data going back as far as 1978, it can also help researchers identify any long-term trends in the timing of spawning and provide additional evidence for differentiating very closely related coral species.It will also provide an important baseline against which to evaluate future changes in regional and global patterns of spawning times or seasonality associated with climate change.Most corals reproduce by expelling eggs and sperm into open water during short night-time spawning events. These events can be highly synchronised within and among species, with millions of colonies spawning at much the same time resulting in one of nature's most spectacular displays.The discovery of multi-species synchronous spawning of scleractinian, or hard, corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. However, much of the data remained unpublished until now, meaning that there was little information about the month, date, and time of spawning or geographical variation in these factors.The new, open access database collates much of the disparate data into one place. The CSD includes over 6,000 observations of the time or day of spawning for more than 300 scleractinian species from 101 sites in tropical regions across the Indian and western Pacific oceans.Dr James Guest, from the School of Natural and Environmental Sciences, Newcastle University, said: "Coral spawning times can be used to address many significant and fundamental questions in coral reef ecology. Knowing when corals spawn can assist coastal management -- for example, if dredging operations cease during mass spawning events. It also has enormous potential for scientific outreach, education and tourism if spawning events can be witnessed in person or remotely."Professor Andrew Baird from the Centre of Excellence for Coral Reefs Studies at James Cook University added: "The CSD is a dynamic database that will grow over time as new observations become available. Anyone can add data at any time by contacting us and we will update the online database annually."Our vision is to help advance many aspects of coral reef science and conservation at a time of unprecedented environmental and societal change. It will accelerate our understanding of coral reproductive biology and provide a baseline against which to evaluate any future changes in the time of spawning."Coral reefs are one of the most species-rich marine ecosystems on the planet and provide enormous societal benefits such as food, tourism and coastal protection. Corals are the ecosystem engineers on reefs and provide much of the habitat complexity in much the same way that trees do in forests.Coral reefs around the world are in sharp decline due to overfishing, pollution and warming seas caused by climate change and successful reproduction is one of the main ways that reefs can recover naturally from human disturbances. It is hoped therefore that the CSD will improve our ability to manage and preserve these remarkable ecosystems. | Climate | 2,021 |
January 29, 2021 | https://www.sciencedaily.com/releases/2021/01/210129090500.htm | Human activity caused the long-term growth of greenhouse gas methane | Methane (CH4) is the second most important greenhouse gas after carbon dioxide (CO | A study by an international team, published in They show that reductions in emissions from Europe and Russia since 1988, particularly from oil-gas exploitation and enteric fermentation, led to the slowed CH4 growth rates in the 1990s, where reduced emissions from natural wetlands due the effects of Mount Pinatubo eruption and frequent El Niño also played roles. This period was followed by the quasi-stationary state of CH4 growth in the early 2000s. CH4 resumed growth from 2007, which were attributed to increases in emissions from coal mining mainly in China and intensification of livestock (ruminant) farming and waste management in Tropical South America, North-central Africa, South and Southeast Asia. While the emission increase from coal mining in China has stalled in the post-2010 period, the emissions from oil and gas sector from North America has increased. There is no evidence of emission enhancement due to climate warming, including the boreal regions, during our analysis period.These findings highlight key sectors (energy, livestock and waste) for effective emission reduction strategies toward climate change mitigation. Tracking the location and source type is critically important for developing mitigation strategies and the implementation the Paris Agreement. The study also underlines need of more atmospheric observations with space and time density higher than the present. | Climate | 2,021 |
January 28, 2021 | https://www.sciencedaily.com/releases/2021/01/210128155623.htm | Loggerhead sea turtles lay eggs in multiple locations to improve reproductive success | Although loggerhead sea turtles return to the same beach where they hatched to lay their eggs, a new study by a USF professor finds individual females lay numerous clutches of eggs in locations miles apart from each other which increases the chance that some of their offspring will survive. | A study published in the journal "Nesting females don't lay all their eggs in one basket. Their reproductive strategy is like investing in a mutual fund. Females divide their resources among many stocks rather than investing everything in a single stock," said Deby Cassill, biology professor at USF's St. Petersburg campus and author of the study.During their 50-year lifetime, a single female loggerhead will produce around 4,200 eggs and scatter them at 40 different sites on the barrier island. This strategy helps reduce the risk of complete reproductive failure by hurricanes and thunderstorms that could wash out or flood all clutches."Because females diversify reproduction in unpredictable patterns over time and space, nearly two-thirds of loggerhead sea turtle hatchlings made it into the Gulf of Mexico," said Cassill.For the study, Cassill analyzed 17 years of data provided by the Conservancy of Southwest Florida on loggerhead females nesting on Keewaydin Island off the southwestern Gulf coast of Florida. For years, conservancy staff and community volunteers tagged turtles and patrolled the island to monitor and record detailed information on the nesting population.Though the study shows most sea turtle hatchlings reach the Gulf of Mexico, future impacts due to human encroachment and climate change could affect the population. Increased frequency of extreme storms due to warmer waters and sea-level rise may flood or wash away larger portions of clutches, leading to population declines of the threatened species."It's important to follow individuals over time to really get a glimpse of how they mate, find food and ensure that some of their young survive to maturity. Without knowledge of the sea turtle's survival and reproductive biology, we cannot develop and implement effective conservation policies," said Cassill.The study is one in a series of upcoming articles by Cassill pertaining to her "maternal risk management model," which looks at how natural selection pressures, such as predators, storms and resource scarcity, influence how mothers invest in offspring quantity and quality.She argues turtles and fish invest in large numbers of offspring when the likelihood their offspring will be killed by predators is high. Mammal mothers like whales and elephants provide extensive care to one offspring at a time when the likelihood their young will starve during seasonal droughts is high.The model, based on the number and size of offspring produced by a mother, extends Darwin's theory of natural selection by explaining the fusion of parents and offspring into family units and societies. | Climate | 2,021 |
January 28, 2021 | https://www.sciencedaily.com/releases/2021/01/210128134646.htm | US must unify atmospheric biology research or risk national security, experts urge | Global circulating winds can carry bacteria, fungal spores, viruses and pollen over long distances and across national borders, but the United States is ill-prepared to confront future disease outbreaks or food-supply threats caused by airborne organisms, says a new paper published in the Ecological Society of America's journal | Claire Williams, the paper's primary author and a research professor at American University, has spent decades studying long-range transport of tree pollen. Her early findings led to collaborations with German and Russian scientists who conducted a wide range of research -- on forest genetics, atmospheric chemistry and climate change -- all under the unifying theme of atmospheric biology."The more I learned about pollen aloft, the more I came to understand that pollen is part of a large airborne milieu of what I call 'aerial plankton' -- bacteria, fungi, lichen soredia [reproductive structures], insect parts, viruses and more," said Williams.Zotino Tall Tower Observation Facility (ZOTTO) and its surrounding forests in central Siberia. Photo courtesy of Anastasia Makhnykina, Sukachev Institute of Forest, Krasnoyarsk, Russia.Now, having seen the highly integrated and well-funded atmospheric biology research underway in Germany and Russia, Williams wants U.S. leaders to understand the value of atmospheric biology to national security -- and recognize that the United States is coming up short.The persistent threat of Valley Fever is one example of how well-coordinated research is critical when responding to threats. Valley Fever is caused by the inhalation of An aerial view from the Aircraft Bioaerosol Collector 2 (ABC-2) science flight in the lower troposphere over the Sierra Nevada mountain range in June 2018. Photo courtesy of NASA.In the United States, research and monitoring of airborne organisms is split between an array of federal agencies. The Department of Agriculture monitors airborne pathogens that threaten food supply, the Department of Defense oversees biological warfare agents such as anthrax, the Center for Disease Control studies human-health impacts of airborne pathogens, and additional contributions to atmospheric biology research are spread across the National Institutes of Health, United States Geological Survey, National Aeronautics and Space Administration, National Science Foundation, Department of Energy and National Oceanic and Atmospheric Administration.While it makes sense for each department or agency to carry out research relevant to its responsibilities and interests, the lack of coordination and information-sharing can effectively cripple the U.S. response to national security threats, such as pandemics, that require cooperation and input from multiple agencies."The time has come -- after all, pandemics are caused by airborne viruses and a host of airborne pathogens, pests and parasites," said Williams. "If we pieced together the expertise that we do have in a host of U.S. science agencies, we would be better prepared for the next pandemic or disease outbreak." | Climate | 2,021 |
January 28, 2021 | https://www.sciencedaily.com/releases/2021/01/210128091137.htm | 635 million-year-old fungi-like microfossil that bailed us out of an ice age discovered | When you think of fungi, what comes to mind may be a crucial ingredient in a recipe or their amazing ability to break down dead organic matter into vital nutrients. But new research by Shuhai Xiao, a professor of geosciences with the Virginia Tech College of Science, and Tian Gan, a visiting Ph.D. student in the Xiao lab, highlights yet another important role that fungi have played throughout the Earth's history: helping the planet recover from an ice age. | A team of scientists from Virginia Tech, the Chinese Academy of Sciences, Guizhou Education University, and University of Cincinnati has discovered the remains of a fungi-like microfossil that emerged at the end of an ice age some 635 million years ago. It is the oldest terrestrial fossil ever found. To put it into perspective, this microfossil predates the oldest dinosaurs about three times over.Their findings were published in The fossil was found in small cavities within well-studied sedimentary dolostone rocks of the lowermost Doushantuo Formation in South China. Although the Doushantuo Formation has provided a plethora of fossils to date, researchers did not expect to find any fossils toward the lower base of the dolostones.But against all odds, Gan found a few long, thread-like filaments -- one of the key characteristics of fungi."It was an accidental discovery," said Gan. "At that moment, we realized that this could be the fossil that scientists have been looking for a long time. If our interpretation is correct, it will be helpful for understanding the paleoclimate change and early life evolution."This discovery is key for understanding multiple turning points throughout Earth's history: the Ediacaran period and the terrestrialization of fungi.When the Ediacaran period began, the planet was recovering from a catastrophic ice age, also known as the "snowball Earth." At that time, ocean surfaces were frozen to a depth of more than a kilometer and it was an incredibly harsh environment for virtually any living organism, except for some microscopic life that managed to thrive. Scientists have long wondered how life ever returned to normalcy -- and how the biosphere was able to grow larger and more complex than ever before.With this new fossil in hand, Tian and Xiao are certain that these microscopic, low profile cave dwellers played numerous roles in the reconditioning of the terrestrial environment in the Ediacaran time. One role involved their formidable digestive system.Fungi have a rather unique digestive system that plays an even greater role in the cycling of vital nutrients. Using enzymes secreted into the environment, terrestrial fungi can chemically break down rocks and other tough organic matter, which can then be recycled and exported into the ocean."Fungi have a mutualistic relationship with the roots of plants, which helps them mobilize minerals, such as phosphorus. Because of their connection to terrestrial plants and important nutritional cycles, terrestrial fungi have a driving influence on biochemical weathering, the global biogeochemical cycle, and ecological interactions," said Gan.Although previous evidence stated that terrestrial plants and fungi formed a symbiotic relationship around 400 million years ago, this new discovery has recalibrated the timeline of when these two kingdoms colonized the land."The question used to be: 'Were there fungi in the terrestrial realm before the rise of terrestrial plants'," said Xiao, an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center. "And I think our study suggests yes. Our fungus-like fossil is 240 million years older than the previous record. This is, thus far, the oldest record of terrestrial fungi."Now, new questions have arisen. Since the fossilized filaments were accompanied by other fossils, Gan will set out to explore their past relationships."One of my goals is to constrain the phylogenetic affinities of these other types of fossils that are associated with the fungal fossils," said Gan.Xiao is thrilled to tackle the environmental aspects of these microorganism. Sixty years ago, few believed that microorganisms, like bacteria and fungi, could be preserved as fossils. Now that Xiao has seen them with his very eyes, he plans to learn more about how they have been virtually frozen in time."It is always important to understand the organisms in the environmental context," said Xiao. "We have a general idea that they lived in small cavities in dolostone rocks. But little is known about how exactly they lived and how they were preserved. Why can something like fungi, which have no bones or shells, be preserved in the fossil record?"However, it can't be said for sure if this fossil is a definitive fungus. Although there is a fair amount of evidence behind it, the investigation into these microfossils is ongoing."We would like to leave things open for other possibilities, as a part of our scientific inquiry," said Xiao. "The best way to put it is that perhaps we have not disapproved that they are fungi, but they are the best interpretation that we have at the moment."Three distinct groups and labs at Virginia Tech were crucial for the identification and timestamping of this fossil. The Confocal Laser Scanning and Microscopy lab at the Fralin Life Sciences Institute helped Tian and Xiao perform initial analysis that prompted further investigation at the University of Cincinnati.The Department of Biological Sciences' Massey Herbarium, which houses over 115,000 specimens of vascular plants, fungi, bryophytes, and lichens, provided modern fungal specimens for comparison with the fossils.The team called in technicians to conduct geochemical analysis using Secondary Ion Mass Spectrometry, which ionize nanomoles of material from small areas that are a fraction the thickness of a hair strand, to analyze the isotopic abundance of sulfur-32 and sulfur-34 in order to understand the fossilization environment.Advanced computerized tomography was crucial to getting the 3D morphology of the filaments, which are just a few micrometers thick. And a combination of Focused Ion Beam Scanning Electron Microscopy and Transmission Electron Microscopy allowed researchers to cut samples with surgical precision and take an even closer look at every nanometer of the filaments."This wasn't a single person or even a single lab that did this work," said Xiao.Xiao also emphasized the importance of interdisciplinary research in this study and many others."It's very important to encourage the next generation of scientists to be trained in an interdisciplinary light because new discoveries always happen at the interface of different fields," said Xiao. | Climate | 2,021 |
January 27, 2021 | https://www.sciencedaily.com/releases/2021/01/210127152547.htm | Pioneering research unravels hidden origins of Eastern Asia's 'land of milk and honey' | A study has revealed for the first time the ancient origins of one of the world's most important ecosystems by unlocking the mechanism which determined the evolution of its mountains and how they shaped the weather there as well as its flora and fauna. | It was previously thought Southern Tibet and the Himalaya were instrumental in turning the once barren land of eastern Asia into lush forests and abundant coastal regions which became home to a rich array of plant, animal and marine life, including some of the world's rarest species. But new findings, published today in the journal Scientists from a UK-China partnership, including the University of Exeter, used an innovative climate model to simulate vegetation and plant diversity, combined with spectacular new fossil finds, to discover how this unique biodiversity hotspot evolved.Lead author, Dr Shufeng Li, a visiting scientist at the University of Bristol in the UK and associate professor at Xishuangbanna Tropical Botanical Garden (XTBG) Institute in Yunnan, China, said: "Until now it was unknown why the climate changed from that of a dry, arid, almost desert-like ecosystem to that of a lush, wet ecosystem where a vast array of plant, animal, and marine life can be found, including some of the world's rarest species."We conducted 18 sensitivity experiments using different Tibetan topographies representing various late Paleogene to early Neogene conditions, which test almost all possible Tibetan growth evolution scenarios."The findings showed that from the late Paleogene to the early Neogene age, some 23-40 million years ago, the growth of the north and northeastern portion of Tibet was the most important factor because it increased rainfall, especially winter rainfall, over eastern Asia where dry winter conditions existed before.This allowed the development of a stable, wet and warm climate, conducive to the evolution of vast and varied plants and animal species which formed the biodiversity hotspot known today for supplying more than a billion people with fresh water and providing ingredients used for lifesaving pharmaceutical drugs. Rare species of monkey, tiger, leopard, bear, fox, mongoose, hedgehog, seal, dolphin, and sea lion all live in this abundant ecosystem.Earlier research has mainly investigated the impact of Tibetan mountain building much further to the South when India collided with Asia around 55 million years ago, leading to the rise of the Himalaya mountains and, eventually, the vast arid Tibetan Plateau. However, recent work is increasingly showing the creation of the modern Tibetan plateau was complex, and did not rise as one monolithic block as originally believed.Dr Taraka Davies-Barnard, a Postdoctoral Research Fellow in the College of Engineering, Mathematics, and Physicals Sciences at the University of Exeter said: "This collaboration between scientists from across the world has revealed how subtle interactions of climate and environment shaped an area of exceptional biodiversity. We need to cooperate similarly to safeguard this ecosystem for future generations."Co-author Professor Paul Valdes, Professor of Physical Geography at the University of Bristol who led the modelling group, said: "Most previous studies have focused on Southern Tibet and the Himalaya, but our results indicate it is the growth of northern Tibet which is really important."The topography of northern Tibet decreases the East Asian winter monsoon winds in the southern part of China, causing wetter winters in eastern Asia and this allows the expansion of vegetation and biodiversity."So enigmatic was the drastic change that even in Chinese folklore this area is known as the 'Land of Fish and Rice', due to its immense productivity."Without the growth in Northern Tibetan mountains, none of this would exist. But our research should also be taken as a cautionary tale," Professor Valdes explained."A unique set of tectonic and stable climatic conditions over millions of years allowed the development of this rare species rich region of South East Asia. However, global warming, harmful intensive agricultural techniques, forest clearing and lack of integrated conservation to preserve this unique ecosystem means once it is gone, it is gone for good."Professor Zhekun Zhou, of the Chinese Academy of Sciences' XTBG, who led on the fossil analysis, said: "So effectively, without northern Tibetan growth, there would be no 'land of milk and honey' in eastern Asia. This research represents a significant breakthrough in understanding how this remarkably rich region of mountainous terrain and diverse plant life formed." | Climate | 2,021 |
January 27, 2021 | https://www.sciencedaily.com/releases/2021/01/210127140144.htm | Up-trending farming and landscape disruptions threaten Paris climate agreement goals | One of President Joe Biden's first post-inauguration acts was to realign the United States with the Paris climate accord, but a new study led by researchers at the University of California, Irvine demonstrates that rising emissions from human land-use will jeopardize the agreement's goals without substantial changes in agricultural practices. | In a paper published today in "We estimated and attributed global land-use emissions among 229 countries and areas and 169 agricultural products," said lead author Chaopeng Hong, UCI postdoctoral scholar in Earth system science. "We looked into the processes responsible for higher or lower emissions and paid particularly close attention to trends in net COThe researchers learned that poorer countries in Latin America, Southeast Asia and sub-Saharan Africa experienced the most pronounced surge in these "land-use change" emissions.East Asia, South Asia and the Middle East produced fewer greenhouse gases as a result of land-use change, according to the study, but the regions' agricultural emissions were growing strongly as output raced to keep up with population expansion. And more affluent North America, Europe and Oceania showed negative land-use change emissions but nonetheless substantial farm-originated pollution."While the situation in low-income countries is critical, mitigation opportunities in these places are large and clear," said senior author Steve Davis, UCI associate professor of Earth system science. "Improving yields on already cultivated land can avoid clearing more carbon-dense forests for cultivation of soybeans, rice, maize and palm oil, thereby drastically reducing land-use emissions in these countries."The authors suggest that nations in emerging and developed markets also can lessen the emissions intensity of agriculture by adopting more efficient tilling and harvesting methods, by better soil and livestock waste management, and by reducing food waste.In addition, dietary changes could help, according to the study, which says that while red meat supplies only about 1 percent of calories produced globally, it's responsible for up to a quarter of the world's land-use greenhouse gas emissions.Europe has the lowest land-use emissions, at 0.5 tons per person per year, the researchers note, but the figure is substantially higher almost everywhere else, and as the planet's population continues to increase, farmers and policymakers will need to meet and exceed current best practices.The paper highlights some promising technological solutions, such as new ways of cultivating rice that create less methane and dietary supplements for cattle that reduce their harmful emissions by up to 95 percent."Feeding the planet may always generate substantial greenhouse gas emissions," said Davis, a member of the executive board of UCI's Solutions that Scale initiative which seeks answers to the planet's most pressing climate and environmental problems. "Even if we get emissions down to European levels worldwide, with expected population growth, we could still be looking at more than 5 gigatons of land-use emissions per year in 2100, an amount at odds with ambitious international climate goals unless offset by negative emissions."The project -- funded by the National Science Foundation, the German Research Foundation, and the Gordon and Betty Moore Foundation -- also included researchers from the University of California, San Diego; Colorado State University; Stanford University; and Germany's Max Planck Institute for Meteorology. | Climate | 2,021 |
January 27, 2021 | https://www.sciencedaily.com/releases/2021/01/210127140129.htm | Diving into Devonian seas: Ancient marine faunas unlock secrets of warming oceans | Members of Syracuse University's College of Arts and Sciences are shining new light on an enduring mystery -- one that is millions of years in the making. | A team of paleontologists led by Professor Cathryn Newton has increased scientists' understanding of whether Devonian marine faunas, whose fossils are lodged in a unit of bedrock in Central New York known as the Hamilton Group, were stable for millions of years before succumbing to waves of extinctions.Drawing on 15 years of quantitative analysis with fellow professor Jim Brower (who died in 2018), Newton has continued to probe the structure of these ancient fossil communities, among the most renowned on Earth.The group's findings, reported by the Geological Society of America (GSA), provide critical new evidence for the unusual, long-term stability of these Devonian period communities.Such persistence, Newton says, is a longstanding scientific enigma. She and her colleagues tested the hypothesis that these ancient communities displayed coordinated stasis -- a theory that attempts to explain the emergence and disappearance of species across geologic time.Newton and Brower, along with their student Willis Newman G'93, found that Devonian marine communities vary more in species composition than the theory predicts. Newton points out that they sought not to disprove coordinated stasis but rather to gain a more sophisticated understanding of when it is applicable. "Discovering more about the dynamics of these apparently stable Devonian communities is critical," she says. "Such knowledge has immediate significance for marine community changes in our rapidly warming seas."Since geologist James Hall Jr. first published a series of volumes on the region's Devonian fossils and strata in the 1840s, the Hamilton Group has become a magnet for research scientists and amateur collectors alike. Today, Central New York is frequently used to test new ideas about large-scale changes in Earth's organisms and environments.During Middle Devonian time (approximately 380-390 million years ago), the faunal composition of the region changed little over 4-6 million years. "It's a significant amount for marine invertebrate communities to remain stable, or 'locked,'" explains Newton, a professor in the Department of Earth and Environmental Sciences.She, Brower and student researchers spent years examining eight communities of animals that once dwelled in a warm, shallow sea on the northern rim of the Appalachian Basin (which, eons ago, lay south of the equator). When the organisms died, sediment from the seafloor began covering their shells and exoskeletons. Minerals from the sediment gradually seeped into their remains, causing them to fossilize. The process also preserved many of them in living position, conserving original shell materials at some sites.These fossils currently populate exposed bedrock throughout Central New York, ranging from soft, dark, deep-water shale to hard, species-rich, shelf siltstone. "Communities near the top of the bedrock exhibit more taxonomic and ecological diversity than those at the bottom," Newton says. "We can compare the community types and composition through time. They are remarkable sites."Coordinated stasis has been a source of contention since 1995, when it was introduced. At the center of the dispute are two model-based explanations: environmental tracking and ecological locking.Environmental tracking suggests that faunas follow their environment. "Here, periods of relative stasis are flanked by coordinated extinctions or regional disappearances. When the environment changes, so do marine faunas," says Newton, also Professor of Interdisciplinary Sciences and Dean Emerita of Arts and Sciences.Ecological locking, in contrast, views marine faunas as tightly structured communities, resistant to large-scale taxonomic change. Traditionally, this model has been used to describe the stability of lower Hamilton faunas.Newton and her colleagues analyzed more than 80 sample sites, each containing some 300 specimens. Special emphasis was placed on the Cardiff and Pecksport Members, two rock formations in the Finger Lakes region that are part of the ancient Marcellus subgroup, famed for its natural gas reserves."We found that lower Hamilton faunas, with two exceptions, do not have clear counterparts among upper ones. Therefore, our quantitative tests do not support the ecological locking model as an explanation for community stability in these faunas," she continues.Newton considers this project a final tribute to Newman, a professor of biology at the State University of New York at Cortland, who died in 2014, and Brower, who fell seriously ill while the manuscript was being finalized. "Jim knew that he likely would not live to see its publication," says Newton, adding that Brower died as the paper was submitted to GSA.She says this new work extends and, in some ways, completes the team's earlier research by further analyzing community structures in the Marcellus subgroup. "It has the potential to change how scientists view long-term stability in ecological communities." | Climate | 2,021 |
January 27, 2021 | https://www.sciencedaily.com/releases/2021/01/210127122420.htm | Key switchgrass genes identified, which could mean better biofuels ahead | Biologists believe they are one step closer to a long-held goal of making a cheap, widely available plant a source for energy and fuel, meaning one of the next big weapons in the battle against climate change may be able to trace its roots to the side of a Texas highway. | Researchers at The University of Texas at Austin, HudsonAlpha Institute for Biotechnology, the U.S. Department of Energy (DOE) and other institutions have published a complex genome analysis of switchgrass, a promising biofuel crop.The team tied different genes to better performance in varying climates across North America, which now gives scientists a road map for breeding high-yielding switchgrass paired to current and future climate conditions across the United States. Optimizing switchgrass to grow efficiently in many diverse environments is a key component of ensuring its success as a biofuel feedstock.The findings are published today in the journal This quest for better switchgrass began more than a decade ago in the UT Austin lab of Tom Juenger, a professor of integrative biology and a corresponding author of the paper. In requesting samples from the U.S. Department of Agriculture's switchgrass stocks, he noticed a lack of diversity. So, he and his then-postdoctoral researcher, David Lowry, set out to find their own."Originally, a lot of these collections came from us driving around in a pickup truck with a shovel and digging up plants off the side of the road or in parks where we had permits," said Lowry, a co-author of the paper, who is now an assistant professor of plant biology at Michigan State University.Switchgrass is a hardy perennial with deep roots that grows all over the country from Canada to Mexico and is an important component of the tallgrass prairie habitats of central North America. It can reach heights of 12 feet in some areas and is used to control erosion, as a game cover and occasionally as food for cattle.But its most important use may come as a source of biofuel, which is a critical component of lowering atmospheric carbon levels and combatting climate change. The ultimate goal of the research is to develop high-yielding varieties of switchgrass matched to one or more of the many different climates and eco-regions of the United States.Juenger, Lowry and colleagues from HudsonAlpha Institute for Biotechnology and the DOE Joint Genome Institute created 10 identical gardens in eight states, growing clones of more than 1,000 switchgrass samples collected from across North America. They sequenced the genetic diversity of these samples and assembled a high-quality reference genome sequence to compare the diversity. They then chronicled which varieties thrived and where, matching sections of their genomes with specific traits that had evolved over millennia to specific climates throughout the continent."We ended up finding three very distinct populations of switchgrass from three regions of the United States, all of which had their own sets of adaptations to climate," said Alice MacQueen, who is a first author of the paper and a research associate at UT Austin. "It means there are potentially multiple evolutionary paths available to match switchgrass plants to particular climates." | Climate | 2,021 |
January 27, 2021 | https://www.sciencedaily.com/releases/2021/01/210127093213.htm | New study identifies bird species that could spread ticks and Lyme disease | Birds play an underrecognized role in spreading tickborne disease due to their capacity for long-distance travel and tendency to split their time in different parts of the world -- patterns that are shifting due to climate change. Knowing which bird species are able to infect ticks with pathogens can help scientists predict where tickborne diseases might emerge and pose a health risk to people. | A new study published in the journal Lead author Daniel Becker, a Postdoctoral Fellow at Indiana University, says, "We know birds can infect ticks with the Lyme bacterium; however, until now, no one has systematically studied the ecological and evolutionary drivers that influence which bird species are most likely to host and spread Borrelia burgdorferi on a global scale. We set out to fill this gap by identifying traits of bird species that are most likely to pass Lyme to feeding ticks."Senior author Barbara Han, a disease ecologist at Cary Institute of Ecosystem Studies, says, "To predict and monitor species that could spread tickborne diseases to people, we first need to know which traits make certain animals good pathogen hosts. Here, we used machine learning to assess bird species traits, paired with Lyme infection data from ticks found on birds, to predict bird species that have the potential to spread Lyme."In this study, the team searched published literature to locate studies reporting Lyme infection of ticks found feeding on birds. The global search yielded 102 studies, including data from ticks found on 183 bird species; of these, 91 carried ticks that tested positive for Borrelia burgdorferi. These bird species are considered 'competent' reservoir species because they are known to infect feeding ticks with Borrelia burgdorferi. Species flagged have a broad range, reaching across the Americas, Africa, Asia, and Oceania.Next, machine learning was used to compare traits of competent bird species with 4691 other bird species. Data included information on life history features like diet composition, foraging location, body size, lifespan, reproductive rate, and fledgling age, as well as geographical information like migration distance, global dispersal, and maximum elevation. They also looked at baseline corticosterone -- the stress hormone in birds -- which can influence susceptibility to infection.The model identified birds that were known to spread Lyme to ticks with 80% accuracy, and revealed 21 new species that should be prioritized for surveillance based on sharing traits with known competent species. High-risk species tend to have low baseline corticosterone, breed and winter at high latitudes and low elevations, are broadly distributed, and occur on either extreme of the pace-of-life continuum (species that breed early and die young, or breed late and are longer lived).Species from the genus Turdus, commonly known as true thrushes, were found to have a significantly greater likelihood of competence compared to other taxa. This finding suggests that thrushes might be the riskiest bird species for Lyme transmission. Passerines, or perching birds, also tended to have higher competence, as did birds that primarily eat seeds and those that forage on the ground -- a behavior that would put them in reach of questing ticks.Identifying Lyme-competent bird species could have direct implications for our health. Tickborne diseases, especially Lyme disease, can be difficult to diagnose. Knowing where ticks and the diseases they carry are spreading can help medical practitioners prepare for diagnosis and treatment, improving health outcomes for patients.Due to climate change, the breeding ranges of many birds are shifting north. As birds spread into higher latitudes, so do ticks and pathogens. Some bird species have taken up full or part-time residence in cities and suburbs. Birds that can succeed in developed environments, especially those that are overwintering in these new places in close proximity to people, increase residents' risk of contracting a tickborne disease.Becker says, "Birds don't spread Lyme directly to people, but they can carry infected ticks to new locations with no history of Lyme occurrence. A tick could drop off a bird and into a garden or yard, where it could later bite and infect a person. If local medical practitioners are unfamiliar with Lyme symptoms, proper diagnosis could be delayed. Identifying where ticks are spreading could improve medical response to Lyme and other tickborne diseases."Han concludes, "These findings remind us that pathogen competence varies tremendously, even among animals of the same family. Machine learning techniques allow us to analyze animal traits and help us predict risky species on a global scale -- not only for Lyme, but for other tickborne and zoonotic diseases that involve multiple host species. These predictions could provide crucial information to guide early interventions, prevent disease spillover, and protect our health." | Climate | 2,021 |
January 27, 2021 | https://www.sciencedaily.com/releases/2021/01/210127085231.htm | Carbon-chomping soil bacteria may pose hidden climate risk | Much of the earth's carbon is trapped in soil, and scientists have assumed that potential climate-warming compounds would safely stay there for centuries. But new research from Princeton University shows that carbon molecules can potentially escape the soil much faster than previously thought. The findings suggest a key role for some types of soil bacteria, which can produce enzymes that break down large carbon-based molecules and allow carbon dioxide to escape into the air. | More carbon is stored in soil than in all the planet's plants and atmosphere combined, and soil absorbs about 20% of human-generated carbon emissions. Yet, factors that affect carbon storage and release from soil have been challenging to study, placing limits on the relevance of soil carbon models for predicting climate change. The new results help explain growing evidence that large carbon molecules can be released from soil more quickly than is assumed in common models."We provided a new insight, which is the surprising role of biology and its linkage to whether carbon remains stored" in soil, said coauthor Howard Stone, the Donald R. Dixon '69 and Elizabeth W. Dixon Professor of Mechanical and Aerospace Engineering.In a paper published Jan. 27 in The "chip" was a modified microscope slide, or a microfluidic device, containing silicone-walled channels half a centimeter long and several times the width of a human hair (about 400 micrometers). Inlet and outlet tubes at each end of the channels allowed the researchers to inject the synthetic clay solution, followed by suspensions containing carbon molecules, bacteria or enzymes.After coating the channels with the see-through clay, the researchers added fluorescently labeled sugar molecules to simulate carbon-containing nutrients that leak from plants' roots, particularly during rainfall. The experiments enabled the researchers to directly observe carbon compounds' locations within the clay and their movements in response to fluid flow in real time.Both small and large sugar-based molecules stuck to the synthetic clay as they flowed through the device. Consistent with current models, small molecules were easily dislodged, while larger ones remained trapped in the clay.When the researchers added Pseudomonas aeruginosa, a common soil bacterium, to the soil-on-a-chip device, the bacteria could not reach the nutrients lodged within the clay's small pores. However, the enzyme dextranase, which represents enzymes released by certain soil bacteria, could break down the nutrients within the synthetic clay and make smaller sugar molecules available to fuel bacterial metabolism. In the environment, this could lead large amounts of CO2 to be released from soil into the atmosphere.Researchers have often assumed that larger carbon compounds are protected from release once they stick to clay surfaces, resulting in long-term carbon storage. Some recent field studies have shown that these compounds can detach from clay, but the reason for this has been mysterious, said lead author Yang, who conducted the research as a postdoctoral fellow at Princeton and is now an assistant professor at the University of Minnesota."This is a very important phenomenon, because it's suggesting that the carbon sequestered in the soil can be released [and play a role in] future climate change," said Yang. "We are providing direct evidence of how this carbon can be released -- we found out that the enzymes produced by bacteria play an important role, but this has often been ignored by climate modeling studies" that assume clay protects carbon in soils for thousands of years.The study sprang from conversations between Stone and coauthor Ian Bourg, an assistant professor of civil and environmental engineering and the High Meadows Environmental Institute. Stone's lab has used microfluidic devices to study the properties of synthetic fibers and bacterial biofilms, while Bourg has expertise in the surface geochemistry of clay minerals -- which are thought to contribute most to soil carbon storage due to their fine-scale structure and surface charges.Stone, Bourg and their colleagues realized there was a need to experimentally test some of the assumptions in widely used models of carbon storage. Yang joined Stone's group to lead the research, and also collaborated with Xinning Zhang, an assistant professor of geosciences and the High Meadows Environmental Institute who investigates the metabolisms of bacteria and their interactions with the soil environment.Jinyun Tang, a research scientist in the climate sciences department at Lawrence Berkeley National Laboratory, noted that in recent years he and others have observed the degradation of large carbon molecules in soils and hypothesized that it was mediated by biologically produced enzymes.The Princeton team's observations "provide a very strong support to our hypothesis," said Tang, who was not involved in the study. He added that the study's technique could also be used to explore such questions as "Will the reversible interaction between small-size carbon molecules and clay particles induce carbon starvation to the microbes and contribute to carbon stabilization? And how do such interactions help maintain microbial diversity in soil? It is a very exciting start."Future studies will test whether bacteria in the model system can release their own enzymes to degrade large carbon molecules and use them for energy, releasing COWhile the carbon stabilization Tang described is possible, the newly discovered phenomenon could also have the opposite effect, contributing to a positive feedback loop with the potential to exacerbate the pace of climate change, the study's authors said. Other experiments have shown a "priming" effect, in which increases in small sugar molecules in soil lead to release of soil carbon, which may in turn cause bacteria to grow more quickly and release more enzymes to further break down larger carbon molecules, leading to still further increases in bacterial activity.The study was supported by the Grand Challenges program and the Carbon Mitigation Initiative of Princeton's High Meadows Environmental Institute. | Climate | 2,021 |
January 27, 2021 | https://www.sciencedaily.com/releases/2021/01/210127085224.htm | Harpy eagles could be under greater threat than previously thought | Harpy eagles are considered by many to be among the planet's most spectacular birds. They are also among its most elusive, generally avoiding areas disturbed by human activity -- therefore already having vanished from portions of its range -- and listed by the International Union for the Conservation of Nature (IUCN) as being 'Near-Threatened'. | However, new research led by the University of Plymouth (UK) suggests estimates of the species' current distribution are potentially overestimating range size.Using a combination of physical sightings and environmental data, they developed a spatial modelling framework which aims to estimate current and past distributions based on the birds' preferred habitat conditions.The authors then used the model to estimate a current range size 11% smaller than that referenced by the IUCN, with high climatic moisture being the most important factor influencing distribution, followed by a minimum temperature of the warmest month of approximately 27°C.Based on past and future climatic projections, the researchers showed that harpy eagle distribution will remain stable in the central Amazon, Guyana, eastern Colombia, and Panama, making these regions especially important for their conservation.In order to ensure their future persistence, the authors suggest current and future conservation policies such as reducing deforestation and addressing issues of persecution should take such spatial models into account.The research is published in the journal Luke Sutton, a PhD student in the University of Plymouth's School of Biological and Marine Sciences and lead author on the research, said: "Harpy eagles are difficult to observe and live at low population densities, so there has been limited research into what environmental factors influence their range limits. Our study shows that predicted future climate stability will be in core areas with extensive lowland tropical forest habitat. That means habitat loss as a result of deforestation is the greatest threat they face, and conservation plans need to take all of that into account."Senior author Dr Robert Puschendorf, Lecturer in Conservation Biology, added: "More than half of all global raptor species have declining populations. So understanding more about where they choose to live and why should be a critical factor when we are looking at how best to go about conserving raptor populations. The type of model we have presented here is lacking for many rare and threatened species, particularly in tropical regions, but can be a cost-effective and rapid way to direct conservation planning for threatened species."Harpy eagles are among the world's largest and most powerful eagles and historically ranged across lowland tropical forests from Mexico in the north to Argentina in the south.However, they became locally extinct in parts of Central America and Brazil during the 20th century. Currently there are multiple conservation programmes in place to better understand population dynamics and conserve rainforest habitat to help ensure its future survival. | Climate | 2,021 |
January 27, 2021 | https://www.sciencedaily.com/releases/2021/01/210127085217.htm | Ancient indigenous New Mexican community knew how to sustainably coexist with wildfire | Wildfires are the enemy when they threaten homes in California and elsewhere. But a new study led by SMU suggests that people living in fire-prone places can learn to manage fire as an ally to prevent dangerous blazes, just like people who lived nearly 1,000 years ago. | "We shouldn't be asking how to avoid fire and smoke," said SMU anthropologist and lead author Christopher Roos. "We should ask ourselves what kind of fire and smoke do we want to coexist with."An interdisciplinary team of scientists published a study in the journal Jemez people learned how to live with and manage fire long agoAncestors of the Native American community in the Jemez Mountains of northern New Mexico lived continuously in fire-prone forests for more than five centuries. Similar to today's communities in the western U.S. forests, Pueblos of the Jemez people had relatively high population densities, and the forested landscape they managed was an area larger than the city of Chicago.Starting in the 1100s, the Jemez people limited fire spread and improved forest resilience to climate variability by creating purposeful burning of small patches of the forest around their community, researchers found."The area around each village would have been a fire-free zone," Roos said. "There were no living trees within two football fields of each village, and the hundreds or thousands of trampling feet mean that fine fuels, such as grasses, herbs, and shrubs, to carry surface fires would have been rare too. The agricultural areas would have seen targeted applications of fire to clean fields after harvest, to recycle plant nutrients as fertilizer, and to clear new fields."Roos calls those controlled burns "the right kind of fire and smoke." The Jemez practice of burning wood for heat, light, and cooking in their homes also removed much of the fuel that could burn in wildfires, he said.Roos said the ancient Jemez model could work today. Many communities in the western United States, including those of Native Americans, still rely on wood-burning to generate heat during the winter, he said. Regularly setting small, low-intensity fires in a patchwork around where people live to clear out flammable material would also follow the Jemez model, he said."Some sort of public-private tribal partnership might do a lot of good, empowering tribal communities to oversee the removal of the small trees that have overstocked the forests and made them vulnerable to dangerous fires, while also providing wood fuel for people who need it," Roos said.Since 2018, wildfires have destroyed more than 50,000 structures in California alone. Global warming is only expected to make the amount and severity of wildfires worse.Almost every major study of fire activity over the last 10,000 years indicates that climate drives fire activity, particular larger fires. Yet, many examples from traditional societies suggest the role of climate can be blunted or buffered by a patchwork of small, purposeful burns before the peak natural fire season. In the Jemez Mountains, the climate influence was weakened and large fires were rare when Jemez farmers used fire preemptively in many small patches, effectively clearing out the materials that fuel today's megafires.In contrast, today's forests are filled with these young trees, increasing the chances they can generate huge flames and waves of flaming embers that can catch homes on fire.The scientists used a variety of methods to document how Jemez people handled smoke and fire centuries ago, including interviewing tribal elders at Jemez Pueblo. The team also compared tree-ring fire records with paleoclimate records, which indicated that fire activity was disconnected from climate during the time when Jemez's population was at a peak. In addition, charcoal and pollen records show that Jemez people began using fire to establish an agricultural landscape and to promote habitats for large animals, such as mule deer and elk.Roos noted that tolerance of fire and smoke hazards probably went hand-in-hand with recognition of the benefits of fire and smoke."Paul Tosa, former governor of Jemez Pueblo, said 'Fire brings richness to the land,'" Roos noted. "We could do very well to learn from the wisdom of Jemez peoples and change our relationship to fire and smoke at the wildland-urban interface." | Climate | 2,021 |
January 26, 2021 | https://www.sciencedaily.com/releases/2021/01/210126140029.htm | Impact of rising sea temperatures on marine life | Global warming or climate change. It doesn't matter what you call it. What matters is that right now it is having a direct and dramatic effect on marine environments across our planet. | "More immediately pressing than future climate change is the increasing frequency and severity of extreme 'underwater heatwaves' that we are already seeing around the world today," Lauren Nadler, Ph.D., who is an assistant professor in Nova Southeastern University's (NSU) Halmos College of Arts and Sciences . "This phenomenon is what we wanted to both simulate and understand."Nadler is a co-author of a new study on this topic, which you can find published online at As a way to further document how increasing temperatures in our oceans are impacting marine life, Nadler and a team of researchers collected two common coral reef fishes -- the five-lined cardinalfish and the redbelly yellowtail fusilier -- from the northern Great Barrier Reef in Australia. Then, under controlled laboratory conditions, the team gradually increased temperatures by 3.0 degrees Celsius above the average summer temperatures for the area. But don't worry, they didn't boil the fish, rather, they increased the temps so they could measure realistically how each species responded to these warmer conditions over a five-week period.The researchers point out that these underwater heatwaves can cause increases of up to 5 degrees C above seasonal average temperatures over the course of just days and can last for several weeks. This rise in temperature can lead to rapid physiological changes in these reef fishes, which could have long-term effects on survival."We found that the fusilier rapidly responded to thermal stress, with nearly immediate changes detected in gill shape and structure and blood parameters, however, the cardinalfish exhibited a delayed response and was far less able to adjust to the elevated temperatures," said Jacob Johansen, Ph.D., a co-author of the study who is an assistant research professor at the University of Hawaii's Hawaii Institute of Marine Biology at Manoa."More importantly, we identified seven parameters across both species that may be useful as biomarkers for evaluating how fast and to what extent coral reef fishes can cope with increasing temperatures. Our findings greatly improve our current understanding of physiological responses to ongoing thermal threats and disturbances, including which species may be most at risk," said Johansen.The research team emphasises that the study is timely, given the rapid decline of tropical coral reefs worldwide, including the repeated mass coral bleaching and mortality events on the Great Barrier Reef in 2016, 2017, and 2020 -- all caused by summer heatwaves. Nadler indicated that climate change 'winners and losers' will ultimately be determined by the capacity to compensate for thermal stress in both the short term of days, weeks, and months, such as in response to heatwaves as we have demonstrated, and over the longer term of years, decades, and centuries."Our findings are immensely useful for scientists but also for managers, conservation planners, and policy makers charged with protecting important ecosystems, such as coral reefs, as well as communities who rely on coral reefs for food, culture, jobs, and their livelihoods," said Jodie Rummer, Ph.D., an associate professor at James Cook University´s ARC Centre of Excellence for Coral Reef Studies and a co-author of the study. "Collectively, we need to be able to predict which species are going to survive and which will be most vulnerable to climate change so we can take action, as the decisions we make today will determine what coral reefs look like tomorrow." | Climate | 2,021 |
January 26, 2021 | https://www.sciencedaily.com/releases/2021/01/210126134036.htm | Reef fish futures foretold | An international group of scientists is predicting markedly different outcomes for different species of coral reef fishes under climate change -- and have made substantial progress on picking the 'winners and losers'. | Associate Professor Jodie Rummer from James Cook University's ARC Centre of Excellence for Coral Reef Studies co-authored a study that exposed two species of coral reef fishes to elevated temperatures and measured their responses over time."We collected five-lined cardinalfish and redbelly yellowtail fusilier from the Great Barrier Reef, and under controlled conditions in the laboratory at JCU, slowly raised the temperature in their aquaria by 3.0"This temperature range spans the average summer temperatures experienced in the northern Great Barrier Reef. We then routinely measured 18 physiological traits in both species over five weeks," she said.The Intergovernmental Panel on Climate Change predicts sea surface temperatures are expected to rise by 2.0-4.8"Over just a few days, these heatwaves can increase water temperatures by as much as 5She said the fusilier exhibited rapid responses to thermal stress, with nearly immediate changes detected in gill morphology and blood parameters. But the cardinalfish response was delayed, and they seemed far less able to adjust to the elevated temperatures.Importantly, the team identified seven parameters across both species that may be useful as biomarkers for evaluating how fast and to what extent coral reef fishes can cope with elevated temperatures."Our findings greatly improve our current understanding of the physiological responses associated with ongoing thermal threats and disturbances, including which species may be most at risk," said co-author Assistant Research Professor Jacob Johansen, from the Hawaii Institute of Marine Biology.The researchers said the study is timely, given the rapid decline of tropical coral reefs worldwide, including the unprecedented and repeated mass coral bleaching and mortality events on the Great Barrier Reef in 2016, 2017, and 2020 -- all caused by summer heatwaves."Climate change winners and losers will ultimately be determined by their capacity to compensate for thermal stress over both the short term of days, weeks, and months, but also over the longer term of years, decades, and centuries," said co-author Assistant Professor Lauren Nadler from Nova Southeastern University in the United States."Our findings are immensely useful for scientists but also for managers, conservation planners, and policy makers charged with protecting these important ecosystems, not to mention communities who rely on coral reef fishes for food, culture, jobs, and livelihoods."Collectively, we need to have an indication of which species are going to survive and which will be most vulnerable to climate change so we can take action. The decisions we make today will determine what coral reefs look like tomorrow," Dr Rummer said. | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125191851.htm | Increasing ocean temperature threatens Greenland's ice sheet | Scientists at the University of California, Irvine and NASA's Jet Propulsion Laboratory have for the first time quantified how warming coastal waters are impacting individual glaciers in Greenland's fjords. Their work is the subject of a study published recently in | Working under the auspices of the Oceans Melting Greenland mission for the past five years, the researchers used ships and aircraft to survey 226 glaciers in all sectors of one of Earth's largest islands. They found that 74 glaciers situated in deep, steep-walled valleys accounted for nearly half of Greenland's total ice loss between 1992 and 2017.Such fjord-bound glaciers were discovered to be the most subject to undercutting, a process by which warm, salty water at the bottom of the canyons melts the ice from below, causing the masses to break apart more quickly than usual. In contrast, the team found that 51 glaciers positioned in shallower gullies experienced less undercutting and contributed only about 15 percent of the total ice loss."I was surprised by how lopsided it was. The biggest and deepest glaciers are undercut much faster than the smaller glaciers in shallow fjords," said lead author Michael Wood, a post-doctorate researcher at NASA's Jet Propulsion Laboratory in Southern California, who began this research as a doctoral student at UCI. "In other words, the biggest glaciers are the most sensitive to the warming waters and those are the ones really driving Greenland's ice loss."The study highlighted the dynamic whereby deeper fjords allow the intrusion of warmer ocean water than shallow ones, hastening the process of undercutting with some of Greenland's largest glaciers.Greenland is home to one of Earth's only two ice sheets, the largest being Antarctica's. The ice in Greenland is more than two miles (three kilometers) thick in places. At the edges of the land mass, the vast glaciers extending from the ice sheet travel slowly down valleys like icy conveyor belts, which inch into the fjords and then melt or break off as icebergs. The ice is replenished by snowfall that is compressed over time into the ice pack.If the ice sheet were in balance, the amount of snow accumulating on the top would roughly equal the ice lost from melt, evaporation and calving -- chunks breaking free from anchored masses and floating off into the ocean.But the ice sheet has been out of balance since the 1990s. Melt has accelerated and calving has increased, causing glaciers that extend into the sea to retreat back toward land. Together, these are resulting the ice sheet shrinkage.According to the research team, the build-up of warm salty water at the bottom of fjords has been accelerated by increasing temperatures in the summer months, which heat the surfaces of glaciers, creating pools of meltwater. This liquid leaks through cracks in the ice to form subsurface freshwater rivers which flows into the sea where it interacts with salty water beneath fjords.Glacier meltwater is free of salt, so it is lighter than seawater and rises to the surface as a plume, dragging up warm water and putting it in contact with the bottoms of glaciers. Fjord depth is a fairly immutable factor, but other factors such as seawater temperature and the amount of meltwater from glaciers surfaces are greatly impacted by climate warming. All three factors combine to cause accelerated deterioration of Greenland's ice sheet, the researchers said.As the water temperature around Greenland's coastline is predicted to continue to increase in the future, these findings suggest that some climate models may underestimate glacial ice loss by at least a factor of two if they do not account for undercutting by a warm ocean.The study also lends insight into why many of Greenland's glaciers never recovered after an abrupt ocean warming between 1998 and 2007, which caused an increase in ocean temperature by nearly 2 degrees Celsius. Although ocean warming paused between 2008 and 2017, the glaciers had already experienced such extreme undercutting in the previous decade that they continued to retreat at an accelerated rate."We have known for well over a decade that the warmer ocean plays a major role in the evolution of Greenland glaciers," said OMG deputy principal investigator Eric Rignot, also of JPL and UCI. "But for the first time, we have been able to quantify the undercutting effect and demonstrate its dominant impact on the glacier retreat over the past 20 years." | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125191848.htm | Major discovery helps explain coral bleaching | Corals, like all animals, must eat to live. The problem is that most corals grow in tropical waters that are poor in nutrients, sort of like ocean deserts; it's this lack of nutrients that makes the water around coral reefs so crystal clear. Because food is not readily available, corals have developed a remarkable feeding mechanism that involves a symbiotic relationship with single-celled algae. These algae grow inside the corals, using the coral tissue as shelter and absorbing the CO2 that the corals produce. In exchange, the algae provide corals with nutrients they produce through photosynthesis. These algae contain a variety of pigments, which give the coral reefs the colors they're known for. | Over the past 35 years, tropical oceans have experienced multiple major heat waves. Scientists have observed that during these episodes, the algae -- stressed by the warmer temperatures -- release compounds that are toxic to the coral, prompting the coral to expel the algae from their tissue. That means the corals lose their color and their primary food source, and then begin to starve. This is the process of coral bleaching. And it has been occurring more and more frequently, threatening the survival of many reefs, including Australia's Great Barrier Reef. Bleached corals do not necessarily die; their symbiotic algae population can be reestablished if the conditions around a reef return to normal. But if the heat persists, or is aggravated by other factors like pollution, the coral becomes too weak to survive.In a paper published in Scientists already knew that ocean warming is the main factor causing the symbiotic relationship to break down. But what Rädecker's team discovered was that the coral is already in a stressed state and lacking nutrients even before the algae begin releasing toxic compounds. "The roots of the problem are much deeper than we thought, and they involve an early breakdown of the metabolic exchanges in these fascinating organisms," says Anders Meibom, the head of LGB and a coral expert.Rädecker spent more than a year studying a coral reef just off the coast of Thuwal, Saudi Arabia -- the city where the Red Sea Research Center, part of the King Abdullah University of Science and Technology, is located. He then replicated these environmental conditions in the aquaria at the Center so that he could investigate the corals under controlled conditions. The data were then analyzed at several laboratories, including EPFL and the Biology Department at the University of Konstanz in Germany."Based on what we found, we can determine which environmental conditions other than temperature (such as water quality) stress the corals in a reef, and use this information to predict whether the reef will bleach. Our findings can also be used to identify corals that are particularly resistant to bleaching, like those in the Gulf of Aqaba and elsewhere in the Red Sea. That will tell scientists which reefs should be protected because they have a better chance of survival," says Rädecker.According to Meibom, this study makes a major contribution to coral research and sheds new light on earlier observations. "Nils' research has uncovered metabolic mechanisms that play a fundamental role in the coral bleaching process -- and that we didn't understand the importance of until now. I believe he found the key to what's actually going on inside corals when they're stressed by global warming," he says. | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125144552.htm | Wetter weather affects composition, numbers of tiny estuarial phytoplankton | Research from North Carolina State University shows that extreme weather events, such as hurricanes and increased precipitation, affect both the amount and the composition of picophytoplankton in the Neuse River Estuary. The work is a first step in determining how a wetter climate may affect the estuarine ecosystem. | Picophytoplankton are defined as any phytoplankton measuring less than three micrometers in size. Although well studied as part of the oceanic ecosystem and food web, picophytoplankton are understudied in estuarine systems, even though they occur in significant numbers within these environments."Picophytoplankton are important primary producers in aquatic ecosystems," says Ryan Paerl, assistant professor of marine, earth and atmospheric sciences and lead author of the research. "They provide food for larger microorganisms, play a role in carbon fixation and cycling, and are sentinels of good ecosystem health. So understanding the effect of moderate to extreme precipitation events on these tiniest members of the ecosystem gives us a more complete sense of impacts of storms on estuaries and the life within them."Paerl and his team conducted a study of picophytoplankton numbers and composition in the Neuse River Estuary -- a major component of the second largest estuary in the lower U.S. -- from July 2017 to December 2018, taking monthly or bimonthly samples at 11 sites along the estuary and using flow cytometry to identify the amount and composition of picophytoplankton.During "stable" conditions -- warm, sunny weather -- picophytoplankton were found in concentrations of 1 million cells per milliliter. However, increased precipitation overall and the arrival of Hurricane Florence in September 2018 had huge impacts on the picophytoplankton in the estuary, bringing numbers down at least a thousand-fold, to 1,000 cells per milliliter or fewer.The composition of picophytoplankton changed following these extreme weather events as well, from primarily cyanobacteria to primarily picoeukaryotic phytoplankton (PEUK)."We saw that precipitation and resulting increased river flow acts like a hose on these picophytoplankton, flushing them out of the estuary," Paerl says. "Then the PEUKs have mini-blooms after the flushing events. They do really well and grow very quickly after disturbances. The good news for the food web is that PEUKs often can produce excellent nutrients, like fatty acids, and PEUKs are desirable prey so their growth and consumption could be giving the food web a quick shot in the arm after these events."As recent climate reports predict wetter weather in the southeastern U.S., the researchers think that the PEUKs may become more important players in estuarine ecosystems than they are currently."Picophytoplankton make up an average of 40% of all phytoplankton biomass in the Neuse River estuary, and that number can be over 70% during stable warm summer months," Paerl says. "And these picophytoplankton are really impacted by storms -- even those that aren't hurricane strength. The result is a shift in concentration and population that could have long-term effects on food webs and biochemistry in the estuary."The work appears in | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125144500.htm | Boosting the efficiency of carbon capture and conversion systems | Systems for capturing and converting carbon dioxide from power plant emissions could be important tools for curbing climate change, but most are relatively inefficient and expensive. Now, researchers at MIT have developed a method that could significantly boost the performance of systems that use catalytic surfaces to enhance the rates of carbon-sequestering electrochemical reactions. | Such catalytic systems are an attractive option for carbon capture because they can produce useful, valuable products, such as transportation fuels or chemical feedstocks. This output can help to subsidize the process, offsetting the costs of reducing greenhouse gas emissions.In these systems, typically a stream of gas containing carbon dioxide passes through water to deliver carbon dioxide for the electrochemical reaction. The movement through water is sluggish, which slows the rate of conversion of the carbon dioxide. The new design ensures that the carbon dioxide stream stays concentrated in the water right next to the catalyst surface. This concentration, the researchers have shown, can nearly double the performance of the system.The results are described today in the journal "Carbon dioxide sequestration is the challenge of our times," Varanasi says. There are a number of approaches, including geological sequestration, ocean storage, mineralization, and chemical conversion. When it comes to making useful, saleable products out of this greenhouse gas, electrochemical conversion is particularly promising, but it still needs improvements to become economically viable. "The goal of our work was to understand what's the big bottleneck in this process, and to improve or mitigate that bottleneck," he says.The bottleneck turned out to involve the delivery of the carbon dioxide to the catalytic surface that promotes the desired chemical transformations, the researchers found. In these electrochemical systems, the stream of carbon dioxide-containing gases is mixed with water, either under pressure or by bubbling it through a container outfitted with electrodes of a catalyst material such as copper. A voltage is then applied to promote chemical reactions producing carbon compounds that can be transformed into fuels or other products.There are two challenges in such systems: The reaction can proceed so fast that it uses up the supply of carbon dioxide reaching the catalyst more quickly than it can be replenished; and if that happens, a competing reaction -- the splitting of water into hydrogen and oxygen -- can take over and sap much of the energy being put into the reaction.Previous efforts to optimize these reactions by texturing the catalyst surfaces to increase the surface area for reactions had failed to deliver on their expectations, because the carbon dioxide supply to the surface couldn't keep up with the increased reaction rate, thereby switching to hydrogen production over time.The researchers addressed these problems through the use of a gas-attracting surface placed in close proximity to the catalyst material. This material is a specially textured "gasphilic," superhydrophobic material that repels water but allows a smooth layer of gas called a plastron to stay close along its surface. It keeps the incoming flow of carbon dioxide right up against the catalyst so that the desired carbon dioxide conversion reactions can be maximized. By using dye-based pH indicators, the researchers were able to visualize carbon dioxide concentration gradients in the test cell and show that the enhanced concentration of carbon dioxide emanates from the plastron.In a series of lab experiments using this setup, the rate of the carbon conversion reaction nearly doubled. It was also sustained over time, whereas in previous experiments the reaction quickly faded out. The system produced high rates of ethylene, propanol, and ethanol -- a potential automotive fuel. Meanwhile, the competing hydrogen evolution was sharply curtailed. Although the new work makes it possible to fine-tune the system to produce the desired mix of product, in some applications, optimizing for hydrogen production as a fuel might be the desired result, which can also be done."The important metric is selectivity," Khan says, referring to the ability to generate valuable compounds that will be produced by a given mix of materials, textures, and voltages, and to adjust the configuration according to the desired output.By concentrating the carbon dioxide next to the catalyst surface, the new system also produced two new potentially useful carbon compounds, acetone, and acetate, that had not previously been detected in any such electrochemical systems at appreciable rates.In this initial laboratory work, a single strip of the hydrophobic, gas-attracting material was placed next to a single copper electrode, but in future work a practical device might be made using a dense set of interleaved pairs of plates, Varanasi suggests.Compared to previous work on electrochemical carbon reduction with nanostructure catalysts, Varanasi says, "we significantly outperform them all, because even though it's the same catalyst, it's how we are delivering the carbon dioxide that changes the game." | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125113133.htm | Climate change in antiquity: Mass emigration due to water scarcity | The absence of monsoon rains at the source of the Nile was the cause of migrations and the demise of entire settlements in the late Roman province of Egypt. This demographic development has been compared with environmental data for the first time by professor of ancient history, Sabine Huebner of the University of Basel -- leading to a discovery of climate change and its consequences. | The oasis-like Faiyum region, roughly 130 km south-west of Cairo, was the breadbasket of the Roman Empire. Yet at the end of the third century CE, numerous formerly thriving settlements there declined and were ultimately abandoned by their inhabitants. Previous excavations and contemporary papyri have shown that problems with field irrigation were the cause. Attempts by local farmers to adapt to the dryness and desertification of the farmland -- for example, by changing their agricultural practices -- are also documented.Basel professor of ancient history Sabine R. Huebner has now shown in the US journal A powerful tropical volcanic eruption around 266 CE, which in the following year brought a below-average flood of the Nile, presumably also played a role. Major eruptions are known from sulfuric acid deposits in ice cores from Greenland and Antarctica, and can be dated to within three years. Particles hurled up into the stratosphere lead to a cooling of the climate, disrupting the local monsoon system.In the third century CE, the entire Roman Empire was hit by crises that are relatively well documented in the province of Egypt by more than 26,000 preserved papyri (documents written on sheets of papyrus). In the Faiyum region, these include records of inhabitants who switched to growing vines instead of grain or to sheep farming due to the scarcity of water. Others accused their neighbors of water theft or turned to the Roman authorities for tax relief. These and other adaptive strategies of the population delayed the death of their villages for several decades."Like today, the consequences of climate change were not the same everywhere," says Huebner. Although regions at the edge of the desert faced the harshness of the drought, others actually benefited from the influx of people moving from the abandoned villages. "New knowledge about the interaction of climate, environmental changes and social developments is very topical." The climate change of late antiquity was not, however -- unlike today -- caused mainly by humans, but was based on natural fluctuations. | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125094346.htm | Global ice loss increases at record rate | The rate at which ice is disappearing across the planet is speeding up, according to new research. | And the findings also reveal that the Earth lost 28 trillion tonnes of ice between 1994 and 2017 -- equivalent to a sheet of ice 100 metres thick covering the whole of the UK.The figures have been published today (Monday, 25 January) by a research team which is the first to carry out a survey of global ice loss using satellite data.The team, led by the University of Leeds, found that the rate of ice loss from the Earth has increased markedly within the past three decades, from 0.8 trillion tons per year in the 1990s to 1.3 trillion tons per year by 2017.Ice melt across the globe raises sea levels, increases the risk of flooding to coastal communities, and threatens to wipe out natural habitats which wildlife depend on.The findings of the research team, which includes the University of Edinburgh, University College London and data science specialists Earthwave, are published in European Geosciences Union's journal The research, funded by UK Natural Environment Research Council, shows that overall, there has been a 65 % increase in the rate of ice loss over the 23-year survey. This has been mainly driven by steep rises in losses from the polar ice sheets in Antarctica and Greenland.Lead author Dr Thomas Slater, a Research Fellow at Leeds' Centre for Polar Observation and Modelling , said: "Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most."The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change. Sea-level rise on this scale will have very serious impacts on coastal communities this century."Dr Slater said the study was the first of its kind to examine all the ice that is disappearing on Earth, using satellite observations .He added: "Over the past three decades there's been a huge international effort to understand what's happening to individual components in Earth's ice system, revolutionised by satellites which allow us to routinely monitor the vast and inhospitable regions where ice can be found."Our study is the first to combine these efforts and look at all the ice that is being lost from the entire planet."The increase in ice loss has been triggered by warming of the atmosphere and oceans, which have warmed by 0.26°C and 0.12°C per decade since the 1980, respectively. The majority of all ice loss was driven by atmospheric melting (68 %), with the remaining losses (32%) being driven by oceanic melting.The survey covers 215,000 mountain glaciers spread around the planet, the polar ice sheets in Greenland and Antarctica, the ice shelves floating around Antarctica, and sea ice drifting in the Arctic and Southern Oceans.Rising atmospheric temperatures have been the main driver of the decline in Arctic sea ice and mountain glaciers across the globe, while rising ocean temperatures have increased the melting of the Antarctic ice sheet. For the Greenland ice sheet and Antarctic ice shelves, ice losses have been triggered by a combination of rising ocean and atmospheric temperatures.During the survey period, every category lost ice, but the biggest losses were from Arctic Sea ice (7.6 trillion tons) and Antarctic ice shelves (6.5 trillion tons), both of which float on the polar oceans.Dr Isobel Lawrence, a Research Fellow at Leeds' Centre for Polar Observation and Modelling, said: "Sea ice loss doesn't contribute directly to sea level rise but it does have an indirect influence. One of the key roles of Arctic sea ice is to reflect solar radiation back into space which helps keep the Arctic cool."As the sea ice shrinks, more solar energy is being absorbed by the oceans and atmosphere, causing the Arctic to warm faster than anywhere else on the planet."Not only is this speeding up sea ice melt, it's also exacerbating the melting of glaciers and ice sheets which causes sea levels to rise."Half of all losses were from ice on land -- including 6.1 trillion tons from mountain glaciers, 3.8 trillion tons from the Greenland ice sheet, and 2.5 trillion tons from the Antarctic ice sheet. These losses have raised global sea levels by 35 millimetres.It is estimated that for every centimetre of sea level rise, approximately a million people are in danger of being displaced from low-lying homelands.Despite storing only 1 % of the Earth's total ice volume, glaciers have contributed to almost a quarter of the global ice losses over the study period, with all glacier regions around the world losing ice.Report co-author and PhD researcher Inès Otosaka, also from Leeds' Centre for Polar Observation and Modelling, said: "As well as contributing to global mean sea level rise, mountain glaciers are also critical as a freshwater resource for local communities."The retreat of glaciers around the world is therefore of crucial importance at both local and global scales."Just over half (58 %) of the ice loss was from the northern hemisphere, and the remainder (42 %) was from the southern hemisphere. | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125094341.htm | Microbes fuelled by wind-blown mineral dust melt the Greenland ice sheet | Scientists have identified a key nutrient source used by algae living on melting ice surfaces linked to rising sea levels. The Greenland ice sheet -- the second largest ice body in the world after the Antarctic ice sheet -- covers almost 80% of the surface of Greenland. Over the last 25 years, surface melting and water runoff from the ice sheet has increased by about 40%. The international research team, led by the University of Leeds, analysed samples from the southwestern margin on Greenland's 1.7 million km² ice sheet over two years. They discovered that phosphorus containing minerals may be driving ever-larger algal blooms on the Greenland Ice Sheet. As the algal blooms grow they darken the ice surface, decreasing albedo -- the ability to reflect sunlight. The blooms cause increased melting thus contributing to higher sea levels. In particular, a band of low-albedo ice, known as the Dark Zone, has developed along the western margin of the massive ice sheet. | The research, published in By examining the surface dust, the scientists were able to demonstrate how phosphorus is used as a key nutrient to help the algae grow, identifying the phosphorus-bearing mineral hydroxylapatite as the source of fuel for the blooms in the Dark Zone. The hydroxylapatite was blown onto the ice from local rock outcrops.Dr Jenine McCutcheon led the study while at Leeds' School of Earth and Environment, and is now an Assistant Professor at the University of Waterloo, Canada.She said: "The photosynthesis rate of the ice algae improved significantly when we provided them with a source of phosphorus."Our mineralogy results revealed that the phosphorus used by ice algae may be coming from the hydroxylapatite we identified in the mineral dust."It's important to understand the controls on algal growth because of their role in ice sheet darkening."Although algal blooms can cover up to 78% of the bare ice surfaces in the Dark Zone, their abundance and size can vary greatly over time."Dr McCutcheon added: "From one season to the next, algal blooms may change and vary in intensity, making them difficult to model year-to-year."Associate Professor, Jim McQuaid at Leeds' School of Earth and Environment, is a co-author of the paper.He said: "Mineral dust can be transported thousands of miles by wind, but the dust we examined was from local sources. As dryland areas in northerly latitudes become even drier under climate change, we can expect to see more dust transported and deposited on the Greenland Ice Sheet, further fuelling algal blooms."As atmospheric scientist, it's exciting to see how wind-blown mineral dust is linked to algal bloom development and impacts ice sheet melting."Previous studies have shown that since 2000, the melt season in the Dark Zone has progressively started earlier and lasted longer, resulting in reduced ability for the ice sheet to reflect solar radiation.Dr McCutcheon said: "The findings of this study will improve how we predict where algal blooms will happen in the future, and help us gain a better understanding of their role in ice sheet albedo reduction and enhanced melting."Professor Liane G. Benning is the Leeds Principal Investigator of the £4 million Natural Environment Research Council project Black and Bloom, and is now at the German Research Centre for Geosciences in Potsdam, Germany.She said: "The glacier ice algae bio-mine the phosphorus from the minerals fuelling the blooms that cover larger and larger areas each year, leading to more melting and faster rising sea levels."As current ice sheet and climate models do not include this phenomena, this research will advance these models and give us a greater understanding of the annual lifecycle of algal blooms." | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125094332.htm | Paleoclimate study of precipitation and sea ice in Arctic Alaska | Arctic sea ice is rapidly diminishing due to global warming, and scientists have found that sea ice dynamics have a big impact on circulation and precipitation patterns in Arctic Alaska, which lies at a climatological crossroads between the Arctic and North Pacific Oceans. Recent studies -- most of which focus on current trends in the region and on what will happen in the future -- have shown that circulation patterns in the Arctic and North Pacific Oceans influence one another. | Doctoral candidate Ellie Broadman of Northern Arizona University's School of Earth and Sustainability wanted to learn about this relationship on a longer timescale, so she developed and led a study in Arctic Alaska to investigate it. She is the lead author on a paper detailing her team's findings, "Coupled impacts of sea ice variability and North Pacific atmospheric circulation on Holocene hydroclimate in Arctic Alaska," which was recently published in the journal The team, which included NAU Regents' Professor and prominent paleoclimatologist Darrell Kaufman and four noted British scientists as collaborators, compiled a new record of hydroclimatic change over the past 10,000 years in Arctic Alaska, revealing that periods of reduced sea ice result in isotopically heavier precipitation derived from proximal Arctic moisture sources. The researchers supported their findings about this systematic relationship through isotope-enabled model simulations and a compilation of regional paleoclimate records."We developed a new paleoclimate dataset from a lake sediment core that was collected in Arctic Alaska," Broadman said. "That record extends back nearly 10,000 years, and we used it to understand precipitation patterns in the past. We combined that dataset with some model simulations and a bunch of previously published paleoclimate records and interpreted all those different puzzle pieces to try to get a sense of what was happening at a large scale.""Using all these datasets, we showed that there's evidence for a relationship between sea ice in the Arctic and atmospheric circulation in the North Pacific in the past, and that those dynamics can make it wetter or drier in Arctic Alaska. Understanding these long-term dynamics are important for understanding what will happen in the future, because they give us an idea of how different parts of the climate system have responded to one another previously. They reveal some natural processes that are important to understand as we look at the impact of global warming."Broadman was drawn to paleoclimate research while pursuing her undergraduate degree in geography, which she enjoyed because of its interdisciplinary nature."I loved thinking about the connections between natural and human systems. I started working in the paleoecology lab to get some research experience and got hooked. You can do so many things with mud! You can study the influence of humans on the environment, or how fire and vegetation changed over time, or look at really large-scale climate processes, like I did in this paper. And just like geography, paleoclimatology is so interdisciplinary: it draws people from all kinds of academic backgrounds, from anthropology, to ecology, to math and physics and beyond. I love working with people who have all these different backgrounds and interests. I also love learning about the Earth's climate system, and I wanted to become an expert in climate science. So, when I decided to go to graduate school, it was an easy decision to work in this interdisciplinary, climate-focused field."Broadman chose NAU's PhD program in Earth Sciences and Environmental Sustainability for her graduate career. "The main reason I came to NAU was to work with Darrell Kaufman, my advisor. He has an incredible reputation; he does super-interesting and important research and it was a major selling point that his research program is focused on Alaska. As someone interested in climate change, I was drawn to the Arctic. It feels exciting and extremely relevant to study a region where climate is changing faster than anywhere else on the planet. Getting to do field work in Alaska, and specifically in the Arctic National Wildlife Refuge, was a bonus!""As I set out to earn my PhD, my goal was to contribute about the North Pacific, the Arctic, sea ice and how those processes work together to influence climate in Arctic Alaska. It's very satisfying to feel like I accomplished that goal, and I think it feeds the part of my brain that loves to think in terms of big, interconnected systems."Broadman, who plans to graduate in April, is currently applying for a variety of positions. Her interests include policy, land management and science communications as well as teaching and research. | Climate | 2,021 |
January 25, 2021 | https://www.sciencedaily.com/releases/2021/01/210125094328.htm | Nuclear war could trigger big El Niño and decrease seafood | A nuclear war could trigger an unprecedented El Niño-like warming episode in the equatorial Pacific Ocean, slashing algal populations by 40 percent and likely lowering the fish catch, according to a Rutgers-led study. | The research, published in the journal "In our computer simulations, we see a 40 percent reduction in phytoplankton (algae) biomass in the equatorial Pacific, which would likely have downstream effects on larger marine organisms that people eat," said lead author Joshua Coupe, a post-doctoral research associate in the Department of Environmental Sciences in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick. "Previous research has shown that global cooling following a nuclear war could lead to crop failure on land, and our study shows we probably can't rely on seafood to help feed people, at least in that area of the world."Scientists studied climate change in six nuclear war scenarios, focusing on the equatorial Pacific Ocean. The scenarios include a major conflict between the United States and Russia and five smaller wars between India and Pakistan. Such wars could ignite enormous fires that inject millions of tons of soot (black carbon) into the upper atmosphere, blocking sunlight and disrupting Earth's climate.With an Earth system model to simulate the six scenarios, the scientists showed that a large-scale nuclear war could trigger an unprecedented El Niño-like event lasting up to seven years. The El Niño-Southern Oscillation is the largest naturally occurring phenomenon that affects Pacific Ocean circulation, alternating between warm El Niño and cold La Niña events and profoundly influencing marine productivity and fisheries.During a "nuclear Niño," scientists found that precipitation over the Maritime Continent (the area between the Indian and Pacific oceans and surrounding seas) and equatorial Africa would be shut down, largely because of a cooler climate.More importantly, a nuclear Niño would shut down upwelling of deeper, colder waters along the equator in the Pacific Ocean, reducing the upward movement of nutrients that phytoplankton -- the base of the marine food web -- need to survive. Moreover, the diminished sunlight after a nuclear war would drastically reduce photosynthesis, stressing and potentially killing many phytoplankton."Turning to the sea for food after a nuclear war that dramatically reduces crop production on land seems like it would be a good idea," said co-author Alan Robock, a Distinguished Professor in the Department of Environmental Sciences at Rutgers-New Brunswick. "But that would not be a reliable source of the protein we need, and we must prevent nuclear conflict if we want to safeguard our food and Earth's environment." | Climate | 2,021 |
January 23, 2021 | https://www.sciencedaily.com/releases/2021/01/210123091025.htm | Wet and wild: There's lots of water in the world's most explosive volcano | There isn't much in Kamchatka, a remote peninsula in northeastern Russia just across the Bering Sea from Alaska, besides an impressive population of brown bears and the most explosive volcano in the world. | Kamchatka's Shiveluch volcano has had more than 40 violent eruptions over the last 10,000 years. The last gigantic blast occurred in 1964, creating a new crater and covering an area of nearly 100 square kilometers with pyroclastic flows. But Shiveluch is actually currently erupting, as it has been for over 20 years. So why would anyone risk venturing too close?Researchers from Washington University in St. Louis, including Michael Krawczynski, assistant professor of earth and planetary sciences in Arts & Sciences and graduate student Andrea Goltz, brave the harsh conditions on Kamchatka because understanding what makes Shiveluch tick could help scientists understand the global water cycle and gain insights into the plumbing systems of other volcanoes.In a recent study published in the journal "The minerals in these nodules retain the signatures of what was happening early in the magma's evolution, deep in Earth's crust," said Goltz, the lead author of the paper.The researchers found that the conditions inside Shiveluch include roughly 10%-14% water by weight (wt%). Most volcanoes have less than 1% water. For subduction zone volcanoes, the average is usually 4%, rarely exceeding 8 wt%, which is considered superhydrous.Of particular interest is a mineral called amphibole, which acts as a proxy or fingerprint for high water content at known temperature and pressure. The unique chemistry of the mineral tells researchers how much water is present deep underneath Shiveluch."When you convert the chemistry of these two minerals, amphibole and olivine, into temperatures and water contents as we do in this paper, the results are remarkable both in terms of how much water and how low a temperature we're recording," Krawczynski said."The only way to get primitive, pristine materials at low temperatures is to add lots and lots of water," he said. "Adding water to rock has the same effect as adding salt to ice; you're lowering the melting point. In this case, there is so much water that the temperature is reduced to a point where amphiboles can crystallize."Video: | Climate | 2,021 |
January 22, 2021 | https://www.sciencedaily.com/releases/2021/01/210122140632.htm | Climate and carbon cycle trends of the past 50 million years reconciled | Predictions of future climate change require a clear and nuanced understanding of Earth's past climate. In a study published today in | Throughout Earth's history, global climate and the global carbon cycle have undergone significant changes, some of which challenge the current understanding of carbon cycle dynamics.Less carbon dioxide in the atmosphere cools Earth and decreases weathering of rocks and minerals on land over long time scales. Less weathering should lead to a shallower calcite compensation depth (CCD), which is the depth in the ocean where the rate of carbonate material raining down equals the rate of carbonate dissolution (also called "snow line"). The depth of the CCD can be traced over the geologic past by inspecting the calcium carbonate content of seafloor sediment cores.Former oceanography graduate student Nemanja Komar and professor Richard Zeebe, both at the UH Manoa School of Ocean and Earth Science and Technology (SOEST), applied the most comprehensive computer model of the ocean carbonate chemistry and CCD to date, making this the first study that quantitatively ties all the important pieces of the carbon cycle together across the Cenozoic (past 66 million years).Contrary to expectations, the deep-sea carbonate records indicate that as atmospheric carbon dioxide (CO"The variable position of the paleo-CCD over time carries a signal of the combined carbon cycle dynamics of the past," said Komar, lead author of the study. "Tracing the CCD evolution across the Cenozoic and identifying mechanisms responsible for its fluctuations are therefore important in deconvolving past changes in atmospheric COKomar and Zeebe's computer model allowed them to investigate possible mechanisms responsible for the observed long-term trends and provide a mechanism to reconcile all the observations."Surprisingly, we showed that the CCD response was decoupled from changes in silicate and carbonate weathering rates, challenging the long-standing uplift hypothesis, which attributes the CCD response to an increase in weathering rates due to the formation of the Himalayas and is contrary to our findings," said Komar.Their research suggests that the disconnect developed partially because of the increasing proportion of carbonate buried in the open ocean relative to the continental shelf due to the drop in sea level as Earth cooled and continental ice sheets formed. In addition, ocean conditions caused the proliferation of open-ocean carbonate-producing organisms during that period of time."Our work provides new insight into the fundamental processes and feedbacks of the Earth system, which is critical for informing future predictions of changes in climate and carbon cycling," said Komar.The researchers are currently working on new techniques to constrain the chronology of climate and carbon cycle changes over the past 66 million years. | Climate | 2,021 |
January 22, 2021 | https://www.sciencedaily.com/releases/2021/01/210122140616.htm | Tiny particles that seed clouds can form from trace gases over open sea | New results from an atmospheric study over the Eastern North Atlantic reveal that tiny aerosol particles that seed the formation of clouds can form out of next to nothingness over the open ocean. This "new particle formation" occurs when sunlight reacts with molecules of trace gases in the marine boundary layer, the atmosphere within about the first kilometer above Earth's surface. The findings, published in the journal | "When we say 'new particle formation,' we're talking about individual gas molecules, sometimes just a few atoms in size, reacting with sunlight," said study co-author Chongai Kuang, a member of the Environmental and Climate Sciences Department at the U.S. Department of Energy's Brookhaven National Laboratory. "It's interesting to think about how something of that scale can have such an impact on our climate -- on how much energy gets reflected or trapped in our atmosphere," he said.But modeling the details of how aerosol particles form and grow, and how water molecules condense on them to become cloud droplets and clouds, while taking into consideration how different aerosol properties (e.g., their size, number, and spatial distribution) affect those processes is extremely complex -- especially if you don't know where all the aerosols are coming from. So a team of scientists from Brookhaven and collaborators in atmospheric research around the world set out to collect data in a relatively pristine ocean environment. In that setting, they expected the concentration of trace gases to be low and the formation of clouds to be particularly sensitive to aerosol properties -- an ideal "laboratory" for disentangling the complex interactions."This was an experiment that really leveraged broad and collaborative expertise at Brookhaven in aerosol observations and cloud observations," Kuang said. Three of the lead researchers -- lead authors Guangjie Zheng and Yang Wang, and Jian Wang, principal investigator of the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) campaign -- began their involvement with the project while working at Brookhaven and have remained close collaborators with the Lab since moving to Washington University in St. Louis in 2018.The study made use of a long-term ground-based sampling station on Graciosa Island in the Azores (an archipelago 850 miles west of continental Portugal) and a Gulfstream-1 aircraft outfitted with 55 atmospheric instrument systems to take measurements at different altitudes over the island and out at sea. Both the ground station and aircraft belong to the DOE Office of Science's Atmospheric Radiation Measurement (ARM) user facility, managed and operated by a consortium of nine DOE national laboratories.The team flew the aircraft on "porpoise flights," ascending and descending through the boundary layer to get vertical profiles of the particles and precursor gas molecules present at different altitudes. And they coordinated these flights with measurements taken from the ground station.The scientists hadn't expected new particle formation to be happening in the boundary layer in this environment because they expected the concentration of the critical precursor trace gases would be too low."But there were particles that we measured at the surface that were larger than newly formed particles, and we just didn't know where they came from," Kuang said.The aircraft measurements gave them their answer."This aircraft had very specific flight patterns during the measurement campaign," Kuang said. "They saw evidence that new particle formation was happening aloft -- not at the surface but in the upper boundary layer." The evidence included a combination of elevated concentrations of small particles, low concentrations of pre-existing aerosol surface area, and clear signs that reactive trace gases such as dimethyl sulfide were being transported vertically -- along with atmospheric conditions favorable for those gases to react with sunlight."Then, once these aerosol particles form, they attract additional gas molecules, which condense and cause the particles to grow to around 80-90 nanometers in diameter. These larger particles then get transported downward -- and that's what we're measuring at the surface," Kuang said."The surface measurements plus the aircraft measurements give us a really good spatial sense of the aerosol processes that are happening," he noted.At a certain size, the particles grow large enough to attract water vapor, which condenses to form cloud droplets, and eventually clouds.Both the individual aerosol particles suspended in the atmosphere and the clouds they ultimately form can reflect and/or absorb sunlight and affect Earth's temperature, Kuang explained.So now that the scientists know new aerosol particles are forming over the open ocean, what can they do with that information?"We'll take this knowledge of what is happening and make sure this process is captured in simulations of Earth's climate system," Kuang said.Another important question: "If this is such a clean environment, then where are all these precursor gases coming from?" Kuang asked. "There are some important precursor gases generated by biological activity in the ocean (e.g., dimethyl sulfide) that may also lead to new particle formation. That can be a nice follow-on study to this one -- exploring those sources."Understanding the fate of biogenic gases such as dimethyl sulfide, which is a very important source of sulfur in the atmosphere, is key to improving scientists' ability to predict how changes in ocean productivity will affect aerosol formation and, by extension, climate.The research was funded by the DOE Office of Science, DOE's Atmospheric System Research, and by NASA. In addition to the researchers from Brookhaven Lab and Washington University, the collaboration included scientists from Pacific Northwest National Laboratory; Missouri University of Science and Technology; the University of Washington, Seattle; NASA Langley Research Center; Science Systems and Applications Inc. in Hampton, Virginia; the Max Planck Institute for Chemistry in Mainz, Germany; and the Scripps Institution of Oceanography, University of California, San Diego. | Climate | 2,021 |
January 22, 2021 | https://www.sciencedaily.com/releases/2021/01/210122112241.htm | Shift in caribou movements may be tied to human activity | Human activities might have shifted the movement of caribou in and near the Arctic National Wildlife Refuge, according to scientists with the University of Cincinnati. | Each year caribou take on one of nature's longest land migrations, trekking hundreds of miles across Alaska and Canada to find food and give birth in their preferred calving grounds.A UC study published today in the journal Researchers used isotope analysis of antlers shed by female caribou to track their historical patterns of movement over the landscape. Female caribou are unique among deer for growing and shedding antlers each year like males.The study is timely given the auction this year of oil and gas leases in the Arctic National Wildlife Refuge. Indigenous Gwich'in opposed the leases, arguing development could disrupt the migration of caribou they depend on for sustenance.An international team of researchers led by UC geologist Joshua Miller focused on the antlers of female caribou, which are shed within a few days of giving birth each spring. The location where antlers drop marks their spring calving grounds.Caribou then spend the summer growing a new pair of antlers.Miller and his collaborators found that analyses of isotopes from the antlers could not only identify one caribou herd from another but also identify changes in their summer range over time.Miller, an assistant professor in UC's College of Arts and Sciences, traveled extensively across the Arctic during five expeditions with collaborators from the U.S. Fish and Wildlife Service. Using inflatable boats, the team navigated rivers, avoiding bears and enduring mosquitoes to collect caribou antlers across the Arctic National Wildlife Refuge in northeast Alaska."It's one of the most remote places on the planet," Miller said. "So it poses all sorts of logistical challenges. It is a real adventure."The refuge is home to grizzly and polar bears, musk ox and hundreds of thousands of caribou found in different herds. Caribou are an important staple food for Indigenous Alaskans who seasonally hunt them.Two populations of caribou are found in the Arctic Refuge: the Central Arctic herd and the Porcupine caribou herd, which is named for the Porcupine River that flows in the heart of its range. While caribou numbers can fluctuate year to year, the Porcupine herd is home to about 200,000 caribou. The Central Arctic herd has approximately 60,000 more, though its numbers may be declining.The collected antlers were shipped back to Miller's UC geology lab, where researchers, including UC graduate student Abigail Kelly, prepared them for isotopic analysis.Strontium, which is found virtually everywhere on Earth, is absorbed up the food chain through plants that caribou and other herbivores eat. Strontium exists as different isotopes, which vary with the geology like an isotopic footprint. By comparing the ratios of strontium-87 and strontium-86, researchers could track where the antlers were grown.Since new female antlers grow in just a few months each year, they make an ideal time capsule to identify where a caribou has been feeding.Miller said finding the antlers is straightforward on the flatter terraces of the Arctic Refuge away from the thick grass tussocks."On these flat areas, they can be everywhere -- more than 1,000 antlers per square kilometer. In some places, you can find one every several steps," he said.Some of the antlers had been lying on the tundra for hundreds of years. One was dated to the 1300s.Researchers observed a shift in summer movements among caribou in the Central Arctic herd before and after the 1970s. This coincides with three factors known to alter caribou migration: population growth, climate change and increased human disturbances to their summer and calving ranges.Human development in the 1970s included oil field expansion and construction of the Trans-Alaska Pipeline. Previous studies have found that pregnant caribou avoid pipelines and roads while calves born in the vicinity of roads and other development are underweight compared to those living farther from human development."An important future area of research will be to test this shift in preferred summer landscapes using an expanded sampling of antlers shed across each herd's calving grounds," researchers said.Scientists only began studying caribou migration using radio telemetry in the 1970s and '80s. Miller said. With antlers, it is possible to track historical caribou landscape use long before that."The question is, how can we evaluate the effects of human impacts given that we only recently started paying close attention? Antlers provide opportunities to look at the past and fill in some of these gaps in our knowledge," he said."One thing we know about caribou is they often avoid human-modified landscapes: pipelines, roads, tourism lodges," Miller said. "They are surprisingly sensitive to these changes."UC associate professor Brooke Crowley, a study co-author, has employed similar methods to identify critical hunting areas for endangered goshawks in Madagascar, track endangered jaguars in Belize and even follow the migrations of long-extinct animals like mammoths and mastodons."Strontium isotopes allow researchers to understand mobility of animals on temporal and spatial scales that complement other conservation tools," Crowley said. "It is particularly valuable to be able to reconstruct what a species or population did in the past because then we have some baseline data that we can compare to modern trends."The other co-authors included Clément Bataille from the University of Ottawa, Eric Wald from the U.S. Fish and Wildlife Service, Volker Bahn from Wright State University and Patrick Druckenmiller from the University of Alaska Fairbanks.UC doctoral student and paper co-author Madison Gaetano said tools developed by paleontologists to study long-extinct animals are helping researchers answer pressing questions about wildlife conservation."Bones lying on modern landscapes accumulate over many generations and record data that are applicable to a myriad of questions about the evolution and ecology of animals and their ecosystems," Gaetano said. "Our role is to develop methods to access, interpret and apply this information, which I think is nicely demonstrated by this research." | Climate | 2,021 |
January 22, 2021 | https://www.sciencedaily.com/releases/2021/01/210122101632.htm | A large number of gray whales are starving and dying in the eastern North Pacific | It's mid-January 2021, and the first gray whales from the eastern North Pacific population have started to arrive in the breeding lagoons in Baja California, Mexico. Since the start of their southbound migration from their high latitude feeding grounds, several sightings of emaciated gray whales have already been reported along their migration route. | This has raised concern among scientists that the unusual mortality event (UME, an unexpected phenomenon during which a significant number of a marine mammal population dies), that started in January 2019, and which so far has resulted in 378 confirmed gray whale deaths, and possibly many more unrecorded, is entering its third year.The gray whale (Eschrichtius robustus) is the only living species in the family Eschrichtiidae, in honour of the Danish zoologist Daniel Frederik Eschricht. Gray whales undertake annual migrations between feeding grounds in the Bering, Chukchi, and Arctic Seas, and breeding grounds from the Southern California Bight to lagoons along the Pacific coast of Baja California, Mexico.During the summer feeding season, between May and October, the whales build up large amount of energy reserves, mainly in the form of blubber, to support the energetic costs of migration and while residing on the breeding grounds. Sufficient energy reserves is crucial for the reproduction and survival of gray whales, which do not feed during the migration and breeding season.Mary Lou Jones and Steven Swartz, co-author on the current paper, conducted the first research and monitoring of the gray whales from 1977 to 1982 in Laguna San Ignacio (LSI) in Baja California Sur, Mexico. In 2006 with their colleague Dr Jorge Urban, co-author on the current paper, they initiated the Laguna San Ignacio Ecosystem Science Program (LSIESP), a project of the Ocean Foundation, which is a partnership with the Universidad Autónoma de Baja California Sur (UABCS) and international collaborators.In 2017, Dr Fredrik Christiansen from the Aarhus Institute of Advanced Studies and the Dept. of Zoology at Aarhus University, and Professor Lars Bejder from the University of Hawai'i at Manoa, joined LSIESP to study the body condition of gray whales with the use of drone photogrammetry. The technique involves measuring the body length and width of gray whales from vertical photographs taken by drones above the whales, from which a measure of relative body condition (or fatness) of individual whales can be obtained.Already in the second year of sampling, the researchers found a marked decline in the body condition of juvenile and adult gray whales visiting Laguna San Ignacio. The decline was also visible in 2019, at the start of the current UME. The decline in body condition also coincided with a drop in the number of mother-calf pairs sighted in Laguna San Ignacio, which indicated a reduction in the reproductive rate of female gray whales.A similar UME occurred in 1999-2000, when 651 gray whales were recorded dead along the west coast of North America. During that two-year event, the gray whale population declined with about 25% from about 21,000 animals in 1998 to about 16,000 in 2002. It is yet unknown what effects the current UME is having on the eastern North Pacific population.While the study by Dr Fredrik Christiansen and colleagues suggests that the decline in survival and reproductive rates of gray whale during the current UME was caused by starvation, the underlying factors that caused this reduction in body condition has not yet been determined. The fact that gray whales in 2018 and 2019 arrived on their Mexican breeding grounds already in significantly poorer body condition, indicates that this decline must have occurred either during the previous feeding season and/or during the southbound migration."It appears that a large number of gray whales are leaving their feeding grounds already in a poor nutritional state and by the time they have completed the breeding season in Mexico they have depleted their energy reserves and starve to death," says Dr Fredrik Christiansen.A decline in prey availability on the main feeding grounds is hence the most probably explanation for the current UME. Since the late 1980s, there has been a decline in the abundance and biomass of amphipods, the main prey for gray whales, in the central Chirikov Basin, the main feeding area for gray whales in the Bering Sea. This in turn is believed to be caused by warming of Arctic waters as a result of natural and/or human-induced climate change. If that is the case, UMEs like this one might become more frequent, which could result in a decline in gray whale numbers in coming decades.As the world keeps struggling with the Covid-19 pandemic, LSIESP researchers are preparing for the 2021 field season in Laguna San Ignacio to hopefully get one step closer to understanding the full extent of the current gray whale UME. | Climate | 2,021 |
January 22, 2021 | https://www.sciencedaily.com/releases/2021/01/210122084954.htm | Role of dams in reducing global flood exposure under climate change | A new collaborative study led by researchers at the National Institute for Environmental Studies, the University of Tokyo, and Michigan State University exposes the role of dams for mitigating flood risk under climate change. | Flood is amongst the costliest natural disasters. Globally, flood risk is projected to increase in the future, driven by climate change and population growth. The role of dams in flood mitigation, previously unaccounted for, was found to decrease by approximately 15% the number of people globally exposed to historical once-in-100-year floods, downstream of dams during the 21st century.Currently, about half of major river systems worldwide are regulated by dams and more than 3,700 major dams are planned or under construction. Consequently, to realistically assess population exposure to present and future floods, current and future dam landscapes must be integrated into existing flood modeling frameworks.Accounting for dams in river flood simulations, the number of people exposed to the historical once-in-100-year flood below dams were 7.2 and 13.4 million on average over 2006-2099 given a low and a medium-high greenhouse gas emission trajectory (RCP2.6 and RCP6.0, respectively). The populations exposed to flooding below dams decreased on average by 16.3% and 12.8% for the two trajectories compared to simulations not accounting for the flow regulations produced by dams. At the end of the 21st century, the decrease was further extended to 20.6% and 12.9% respectively.To maintain the levels of flood protection that dams have provided, new dam operations will be required to offset the effect of climate change, possibly negatively affecting energy production and water storage. In addition, precise and reliable hydro-meteorological forecasts will be invaluable for enhancing flood protection and avoid excessive outflows. Given the many negative environmental and social impacts of dams, comprehensive assessments that consider both potential benefits and adverse effects are necessary for the sustainable development of water resources. | Climate | 2,021 |
January 22, 2021 | https://www.sciencedaily.com/releases/2021/01/210122085013.htm | Geoscientists reconstruct 6.5 million years of sea level stands in the Western Mediterranean | The pressing concern posed by rising sea levels has created a critical need for scientists to precisely predict how quickly the oceans will rise in coming centuries. To gain insight into future ice sheet stability and sea-level rise, new research from an international team led by University of South Florida geoscientists is drawing on evidence from past interglacial periods when Earth's climate was warmer than today. | Using deposits in the caves of the Mediterranean island of Mallorca, known as phreatic overgrowths on speleothems, to reconstruct past sea level stands, the team was able to determine that the vertical extent of these unique deposits corresponds with the amplitude of the fluctuating water table, said author USF geosciences Professor Bogdan Onac. That determination now is providing scientists with a way to precisely measure past sea levels.Working with colleagues at the University of New Mexico, University of Balearic Islands and Columbia University, the researchers' findings were published in Their results contribute to the understanding of past warm periods to gain insight into the magnitude and frequency of sea level rise, which is critical for scientists' ability to forecast and make recommendations on adapting to future global warming.The team expanded upon their research previously published in Their results show that during key time events, such as Pliocene-Pleistocene Transition, when the Earth underwent a major transition from the warm climates of the Pliocene to the Pleistocene ice ages, the GMSL stood at 6.4 meters. During the beginning and the end of the Mid?Pleistocene Transition the sea level was at -1.1 meter and 5 meters respectively."Overall, our results support that sea level dropped significantly after the Pliocene," said USF doctoral alum Oana Dumitru, the study's lead author who is now a postdoc at Columbia University's Lamont-Doherty Earth Observatory.The authors also show that local sea level before and at the onset of the Messinian Salinity Crisis, a major geological event during which the Mediterranean Sea became partly to nearly dry of water, was at approximately 33 meters above present level. These estimates may offer starting points for assessing whether sea-level drawdown in the Western Mediterranean happened gradually or rapidly, the researchers said."Our estimates are important snapshots of sea level still stands, but additional sea level index points will be useful to yield more context for our results," the team wrote in their journal article. "By providing direct estimates of sea level using POS as robust proxies, this work advances our understanding of sea level position during several past warm periods. These results therefore contribute to efforts of studying past warm periods to gain insight into the magnitude and frequency of sea level rise." | Climate | 2,021 |
January 21, 2021 | https://www.sciencedaily.com/releases/2021/01/210121131818.htm | Antarctica: The ocean cools at the surface but warms up at depth | Scientists from the CNRS, CNES, IRD, Sorbonne Université, l'Université Toulouse III -- Paul Sabatier and their Australian colleagues*, with the support of the IPEV, have provided a comprehensive analysis on the evolution of Southern Ocean temperatures over the last 25 years. The research team has concluded that the slight cooling observed at the surface hides a rapid and marked warming of the waters, to a depth of up to 800 metres. | The study points to major changes around the polar ice cap where temperatures are increasing by 0.04°C per decade, which could have serious consequences for Antarctic ice. Warm water is also rising rapidly to the surface, at a rate of 39 metres per decade, i.e. between three and ten times more than previously estimated.Published in *- The laboratories and institutions involved in this study are the Laboratoire d'océanographie et du climat : expérimentations et approches numériques (CNRS/IRD/MNHN/ Sorbonne Université), part of the l'Institut Pierre Simon Laplace; le Laboratoire d'études en géophysique et océanographie spatiales (CNRS/CNES/IRD/Université Toulouse III -- Paul Sabatier) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO; Australia). The SURVOSTRAL observation programme was funded by IPEV and the CNRS. | Climate | 2,021 |
January 21, 2021 | https://www.sciencedaily.com/releases/2021/01/210121131735.htm | Scientists discover how the potentially oldest coral reefs in the Mediterranean developed | A new study from the Institut de Ciències del Mar (ICM-CSIC, Spain) and the National Oceanography Centre brings unprecedented insights into the environmental constraints and climatic events that controlled the formation of these reefs. | The results of this research will help understand how cold-water coral reefs can react to the effects caused by the present-day climate change.Similar to tropical coral reefs, cold-water coral reefs are incredible hotspots of biodiversity, with the difference that they do not rely on symbiosis with microscopic algae, and therefore can be found in the dark and deep waters of our oceans. Despite their uniqueness and key functional role in the ocean, they are still partially unknown ecosystems, which still lack of thorough procedures to protect them from human-derived disturbances. In fact, they are considered vulnerable marine ecosystems by the United Nations, the OSPAR Commission and the General Fisheries Commission for the Mediterranean.Now, an international team of scientists from the Institut de Ciències del Mar (ICM-CSIC) and the NOC has studied for the first time the main drivers that control the development of cold-water reefs in the Western Mediterranean during the last 400,000 years. In these reefs, the deeper you go, the older the corals will be, since new generations grow on top of the previous ones. The results of this research are collected in a paper published recently in the journal To carry out the study, researchers made use of Laser Ablation U-series dating, a new technique consisting of ablating and ionising samples with an inductively coupled plasma mass spectrometer to determine the age of 110 cold-water coral skeletons. Combined with other analyses, these allowed them to describe when the main periods of reef formation occurred and which were the main environmental drivers of coral reef formation in this region.According to this work, cold-water corals have been growing almost continuously in the Mediterranean for the last 400,000 years, even before the appearance of the first Neanderthals. Nonetheless, they might have started to form much earlier, as only the shallower part -10 m- of the entire reef height -80-90 m- could be described in this study.The analyses of the semi-fossil corals acquired showed that coral growth and reef formation was affected by major changes in climate over this time period. "Climate swings associated with ice ages, such as changes in sea surface productivity and sea-level variations appear to be the main factors controlling the development of these cold-water coral reefs," explains Guillem Corbera, PhD student from NOC and the University of Southampton."In addition, intense and prolonged monsoon events that mainly affected the Eastern Mediterranean Sea had a detrimental impact for the development of these reefs, located 1000s of kilometers away in the Westernmost Mediterranean," adds Corbera."Throughout the last 400,000 years, depending on the climate conditions, different species of corals dominated these reefs, which created impressive geo-forms in the deep ocean. This research helps us understand how cold-water coral reefs can react to the effects caused by the present-day climate change," states the ICM-CSIC researcher Claudio Lo Iacono, who discovered these reefs some years ago and has now led this study.In the Mediterranean Sea the development of cold-water coral reefs has been studied before, and scientists have so far determined the age of coral samples from different locations. They have also attempted to link coral reef formation patterns to different environmental factors, but unlike this article, they have not been able to investigate cold-water coral reef development beyond the last ~15,000 years. | Climate | 2,021 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.