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2538 | Himalayas | Satellites and on-site measurements are observing that Himalayan glaciers are disappearing at an accelerating rate. | Himalayas The Himalayas , or Himalaya , ( -LSB- ˌhɪməˈleɪ.ə -RSB- or -LSB- hɪˈmɑːləjə -RSB- ) form a mountain range in Asia separating the plains of the Indian subcontinent from the Tibetan Plateau . The Himalayan range has many of the Earth 's highest peaks , including the highest , Mount Everest . The Himalayas include over fifty mountains exceeding 7200 m in elevation , including ten of the fourteen 8000m peaks . By contrast , the highest peak outside Asia -- Aconcagua , in the Andes -- is 6961 m tall . The Himalayan range is bordered on the northwest by the Karakoram and Hindu Kush ranges , on the north by the Tibetan Plateau , and on the south by the Indo-Gangetic Plain . The Himalayas are distinct from the other great ranges of central Asia , although sometimes the term Himalaya is loosely used to include the Karakoram and some of the other ranges . The Himalayas are spread across five countries : Nepal , India , Bhutan , China and Pakistan , with the first three countries having sovereignty over most of the range . Some of the world 's major rivers , the Indus , the Ganges , and the Tsangpo-Brahmaputra , rise in the Himalayas , and their combined drainage basin is home to roughly 600 million people . The Himalayas have profoundly shaped the cultures of South Asia ; many Himalayan peaks are sacred in Hinduism and Buddhism . Lifted by the subduction of the Indian tectonic plate under the Eurasian Plate , the Himalayan Mountain range runs , west-northwest to east-southeast , in an arc 2400 km long . Its western anchor , Nanga Parbat , lies just south of the northernmost bend of Indus river . Its eastern anchor , Namcha Barwa , is just west of the great bend of the Tsangpo river . The range varies in width from 400 km in the west to 150 km in the east . |
3063 | Flying_Spaghetti_Monster | 'Another global warming myth comes crashing down. | Flying Spaghetti Monster The Flying Spaghetti Monster ( FSM ) is the deity of the Church of the Flying Spaghetti Monster , or Pastafarianism . Pastafarianism ( a portmanteau of pasta and Rastafarian ) is a social movement that promotes a light-hearted view of religion and opposes the teaching of intelligent design and creationism in public schools . According to adherents , Pastafarianism is a `` real , legitimate religion , as much as any other '' . It is legally recognized as a religion in the Netherlands and New Zealand -- where Pastafarian representatives have been authorized to celebrate weddings and where the first legally recognized Pastafarian wedding was performed in April 2016 . However , in the United States , a federal judge has ruled that the `` Church of the Flying Spaghetti Monster '' is not a real religion . The `` Flying Spaghetti Monster '' was first described in a satirical open letter written by Bobby Henderson in 2005 to protest the Kansas State Board of Education decision to permit teaching intelligent design as an alternative to evolution in public school science classes . In the letter , Henderson demanded equal time in science classrooms for the Flying Spaghetti Monster , alongside intelligent design and evolution . After Henderson published the letter on his website , the Flying Spaghetti Monster rapidly became an Internet phenomenon and a symbol of opposition to the teaching of intelligent design in public schools . Because of its popularity and exposure , the Flying Spaghetti Monster is often used as a contemporary version of Russell 's teapot -- an argument that the philosophic burden of proof lies upon those who make unfalsifiable claims , not on those who reject them . Pastafarianism has received praise from the scientific community and criticism from proponents of intelligent design . Pastafarians have engaged in disputes with creationists , including in Polk County , Florida , where they played a role in dissuading the local school board from adopting new rules on teaching evolution . Pastafarian tenets ( generally satires of creationism ) are presented both on Henderson 's Church of the Flying Spaghetti Monster website , where he is described as `` prophet '' , and in The Gospel of the Flying Spaghetti Monster , written by Henderson in 2006 . The central belief is that an invisible and undetectable Flying Spaghetti Monster created the universe . Pirates are revered as the original Pastafarians . Henderson asserts that a decline in the number of pirates over the years is the cause of global warming . The FSM community congregates at Henderson 's website to share ideas about the Flying Spaghetti Monster and crafts representing images of it . |
1235 | Ice_age | "During ice ages, caused by wobbles in the Earth's orbit, sea levels dropped more than 400 feet as ice piled up on land. | Ice age An ice age is a period of long-term reduction in the temperature of Earth 's surface and atmosphere , resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers . Within a long-term ice age , individual pulses of cold climate are termed `` glacial periods '' ( or alternatively `` glacials '' or `` glaciations '' or colloquially as `` ice age '' ) , and intermittent warm periods are called `` interglacials '' . In the terminology of glaciology , ice age implies the presence of extensive ice sheets in both northern and southern hemispheres . By this definition , we are in an interglacial period -- the Holocene -- of the ice age . The ice age began 2.6 million years ago at the start of the Pleistocene epoch , because the Greenland , Arctic , and Antarctic ice sheets still exist . |
356 | Nick_Bostrom | This requires us to work towards avoiding catastrophic possibilities rather than looking at probabilities, as learning from mistakes is not an option when it comes to existential risks. | Nick Bostrom Nick Bostrom ( -LSB- langˈbɒstrəm -RSB- Niklas Boström , -LSB- ˈbuːˌstrœm -RSB- ; born 10 March 1973 ) is a Swedish philosopher at the University of Oxford known for his work on existential risk , the anthropic principle , human enhancement ethics , superintelligence risks , the reversal test , and consequentialism . In 2011 , he founded the Oxford Martin Programme on the Impacts of Future Technology , and he is currently the founding director of the Future of Humanity Institute at Oxford University . He is the author of over 200 publications , including Superintelligence : Paths , Dangers , Strategies ( 2014 ) , a New York Times bestseller and Anthropic Bias : Observation Selection Effects in Science and Philosophy ( 2002 ) . In 2009 and 2015 , he was included in Foreign Policys Top 100 Global Thinkers list . Bostrom 's work on superintelligence -- and his concern for its existential risk to humanity over the coming century -- has brought both Elon Musk and Bill Gates to similar thinking . |
2394 | Greenland_ice_sheet | (2005), where satellite altimetry established that the mean thickness of the entire Greenland ice sheet had increased at 2 inches per year – a total of almost 2 feet – in the 11 years 1993-2003." | Greenland ice sheet The Greenland ice sheet ( Grønlands indlandsis , Sermersuaq ) is a vast body of ice covering 1710000 km ² , roughly 80 % of the surface of Greenland . It is the second largest ice body in the world , after the Antarctic ice sheet . The ice sheet is almost 2400 km long in a north-south direction , and its greatest width is 1100 km at a latitude of 77 ° N , near its northern margin . The mean altitude of the ice is 2135 m . The thickness is generally more than 2 km and over 3 km at its thickest point . It is not the only ice mass of Greenland -- isolated glaciers and small ice caps cover between 76000 and around the periphery . If the entire 2850000 km3 of ice were to melt , it would lead to a global sea level rise of 7.2 m . The Greenland Ice Sheet is sometimes referred to under the term inland ice , or its Danish equivalent , indlandsis . It is also sometimes referred to as an ice cap . |
2493 | Mount_Kenya | Mount Kilimanjaro's shrinking glacier is complicated and not due to just global warming. | Mount Kenya Mount Kenya is the highest mountain in Kenya and the second-highest in Africa , after Kilimanjaro . The highest peaks of the mountain are Batian ( 5199 m ) , Nelion ( 5188 m ) and Point Lenana ( 4985 m ) . Mount Kenya is located in central Kenya , the heart of Kenya , about 16.5 km south of the equator , around 150 km north-northeast of the capital Nairobi . Mount Kenya is the source of the name of the Republic of Kenya . Mount Kenya is a stratovolcano created approximately 3 million years after the opening of the East African rift . Before glaciation , it was 7000 m high . It was covered by an ice cap for thousands of years . This has resulted in very eroded slopes and numerous valleys radiating from the centre . There are currently 11 small glaciers . The forested slopes are an important source of water for much of Kenya . There are several vegetation bands from the base to the summit . The lower slopes are covered by different types of forest . Many alpine species are endemic to Mount Kenya , such as the giant lobelias and senecios and a local subspecies of rock hyrax . An area of 715 km2 around the centre of the mountain was designated a National Park and listed as a UNESCO World Heritage Site in 1997 . The park receives over 16,000 visitors per year . |
2750 | Ocean_acidification | There is no way for us to prevent the world's CO2 emissions from doubling by 2100" | Ocean acidification Ocean acidification is the ongoing decrease in the pH of the Earth 's oceans , caused by the uptake of carbon dioxide from the atmosphere . Seawater is slightly basic ( meaning pH > 7 ) , and the process in question is a shift towards pH-neutral conditions rather than a transition to acidic conditions ( pH < 7 ) . Ocean alkalinity is not changed by the process , or may increase over long time periods due to carbonate dissolution . An estimated 30 -- 40 % of the carbon dioxide from human activity released into the atmosphere dissolves into oceans , rivers and lakes . To achieve chemical equilibrium , some of it reacts with the water to form carbonic acid . Some of these extra carbonic acid molecules react with a water molecule to give a bicarbonate ion and a hydronium ion , thus increasing ocean acidity ( H + ion concentration ) . Between 1751 and 1996 surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14 , representing an increase of almost 35 % in H + ion concentration in the world 's oceans . Earth System Models project that within the last decade ocean acidity exceeded historical analogues and in combination with other ocean biogeochemical changes could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean . Increasing acidity is thought to have a range of potentially harmful consequences for marine organisms , such as depressing metabolic rates and immune responses in some organisms , and causing coral bleaching . By increasing the presence of free hydrogen ions , each molecule of carbonic acid that forms in the oceans ultimately results in the conversion of two carbonate ions into bicarbonate ions . This net decrease in the amount of carbonate ions available makes it more difficult for marine calcifying organisms , such as coral and some plankton , to form biogenic calcium carbonate , and such structures become vulnerable to dissolution . Ongoing acidification of the oceans threatens food chains connected with the oceans . As members of the InterAcademy Panel , 105 science academies have issued a statement on ocean acidification recommending that by 2050 , global emissions be reduced by at least 50 % compared to the 1990 level . While ongoing ocean acidification is anthropogenic in origin , it has occurred previously in Earth 's history . The most notable example is the Paleocene-Eocene Thermal Maximum ( PETM ) , which occurred approximately 56 million years ago . For reasons that are currently uncertain , massive amounts of carbon entered the ocean and atmosphere , and led to the dissolution of carbonate sediments in all ocean basins . Ocean acidification has been called the `` evil twin of global warming '' and `` the other problem '' . |
494 | Air_National_Guard | The Massachusetts Bay Colony in 1635 experienced a Category 3 or 4 storm, with up to a 20-foot storm surge. | Air National Guard The Air National Guard ( ANG ) , also known as the Air Guard , is a federal military reserve force as well as the militia air force of each U.S. state , the District of Columbia , the Commonwealth of Puerto Rico , and the territories of Guam and the U.S. Virgin Islands . It , along with each state 's , district 's , commonwealth 's or territory 's Army National Guard component , makes up the National Guard of each state and the districts , commonwealths and territories as applicable . When Air National Guard units are used under the jurisdiction of the state governor they are fulfilling their militia role . However , if federalized by order of the President of the United States , ANG units become an active part of the United States Air Force . They are jointly administered by the states and the National Guard Bureau , a joint bureau of the Army and Air Force that oversees the National Guard of the United States . Air National Guard units are organized and federally recognized federal military reserve forces in each of the fifty U.S. states , the Commonwealth of Puerto Rico , the territories of Guam and the U.S. Virgin Islands , and the District of Columbia of the United States . Each state , the District of Columbia and the Commonwealth of Puerto Rico has a minimum of one ANG flying unit with either assigned aircraft or aircraft shared with a unit of the active duty Air Force or the Air Force Reserve under an `` Associate '' arrangement . The ANG of the territories of Guam and the Virgin Islands have no aircraft assigned and perform ground support functions . Air National Guard activities may be located on active duty air force bases , air reserve bases , naval air stations/joint reserve bases , or air national guard bases and stations which are either independent military facilities or collocated as tenants on civilian-controlled joint civil-military airports . ANG units typically operate under Title 32 USC . However , when operating under Title 10 USC all ANG units are operationally gained by an active duty USAF major command ( MAJCOM ) . ANG units of the Combat Air Forces ( CAF ) based in the Continental United States ( CONUS ) , plus a single air control squadron of the Puerto Rico ANG , are gained by the Air Combat Command ( ACC ) . CONUS-based ANG units in the Mobility Air Forces ( MAF ) , plus the Puerto Rico ANG 's airlift wing and the Virgin Islands ANG 's civil engineering squadron are gained by the Air Mobility Command ( AMC ) . The vast majority of ANG units fall under either ACC or AMC . However , there remain a few exceptions , such as the Alaska ANG , Hawaii ANG and Guam ANG , whose CAF and MAF units are operationally gained by Pacific Air Forces ( PACAF ) , while a smaller number of ANG units in CONUS are operationally gained by Air Education and Training Command ( AETC ) , Air Force Global Strike Command ( AFGSC ) , Air Force Special Operations Command ( AFSOC ) , Air Force Space Command ( AFSPC ) , and United States Air Forces in Europe - Air Forces Africa ( USAFE-AFAFRICA ) . |
644 | Coral_reef | an individual heatwave triggering coral bleaching cannot be linked to global warming as the process triggering an individual heatwave is fundamentally different from that triggering global warming | Coral reef Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals . Coral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients . Most coral reefs are built from stony corals , which in turn consist of polyps that cluster in groups . The polyps belong to a group of animals known as Cnidaria , which also includes sea anemones and jellyfish . Unlike sea anemones , corals secrete hard carbonate exoskeletons which support and protect the coral polyps . Most reefs grow best in warm , shallow , clear , sunny and agitated waters . Often called `` rainforests of the sea '' , shallow coral reefs form some of the most diverse ecosystems on Earth . They occupy less than 0.1 % of the world 's ocean surface , about half the area of France , yet they provide a home for at least 25 % of all marine species , including fish , mollusks , worms , crustaceans , echinoderms , sponges , tunicates and other cnidarians . Paradoxically , coral reefs flourish even though they are surrounded by ocean waters that provide few nutrients . They are most commonly found at shallow depths in tropical waters , but deep water and cold water corals also exist on smaller scales in other areas . Coral reefs deliver ecosystem services to tourism , fisheries and shoreline protection . The annual global economic value of coral reefs is estimated between US$ 29.8-375 billion . However , coral reefs are fragile ecosystems , partly because they are very sensitive to water temperature . They are under threat from climate change , oceanic acidification , blast fishing , cyanide fishing for aquarium fish , sunscreen use , overuse of reef resources , and harmful land-use practices , including urban and agricultural runoff and water pollution , which can harm reefs by encouraging excess algal growth . |
2414 | Earth | Ocean and surface temperature measurements find the planet continues to accumulate heat. | Earth Earth ( from Eorðe -LSB- Γαῖα , Gaia -RSB- Terra ) , otherwise known as the World or the Globe , is the third planet from the Sun and the only object in the Universe known to harbor life . It is the densest planet in the Solar System and the largest of the four terrestrial planets . According to radiometric dating and other sources of evidence , Earth formed about 4.54 billion years ago . Earth 's gravity interacts with other objects in space , especially the Sun and the Moon , Earth 's only natural satellite . During one orbit around the Sun , Earth rotates about its axis over 365 times ; thus , an Earth year is about 365.26 days long . Earth 's axis of rotation is tilted , producing seasonal variations on the planet 's surface . The gravitational interaction between the Earth and Moon causes ocean tides , stabilizes the Earth 's orientation on its axis , and gradually slows its rotation . Earth 's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years . About 71 % of Earth 's surface is covered with water , mostly by its oceans . The remaining 29 % is land consisting of continents and islands that together have many lakes , rivers and other sources of water that contribute to the hydrosphere . The majority of Earth 's polar regions are covered in ice , including the Antarctic ice sheet and the sea ice of the Arctic ice pack . Earth 's interior remains active with a solid iron inner core , a liquid outer core that generates the Earth 's magnetic field , and a convecting mantle that drives plate tectonics . Within the first billion years of Earth 's history , life appeared in the oceans and began to affect the Earth 's atmosphere and surface , leading to the proliferation of aerobic and anaerobic organisms . Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago . Since then , the combination of Earth 's distance from the Sun , physical properties , and geological history have allowed life to evolve and thrive . In the history of the Earth , biodiversity has gone through long periods of expansion , occasionally punctuated by mass extinction events . Over 99 % of all species that ever lived on Earth are extinct . Estimates of the number of species on Earth today vary widely ; most species have not been described . Over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival . Humans have developed diverse societies and cultures ; politically , the world has about 200 sovereign states . |
1315 | Urban_heat_island | cold kills many more people than heat. | Urban heat island An urban heat island ( UHI ) is an urban area or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities . The temperature difference usually is larger at night than during the day , and is most apparent when winds are weak . UHI is most noticeable during the summer and winter . The main cause of the urban heat island effect is from the modification of land surfaces . Waste heat generated by energy usage is a secondary contributor . As a population center grows , it tends to expand its area and increase its average temperature . The less-used term heat island refers to any area , populated or not , which is consistently hotter than the surrounding area . Monthly rainfall is greater downwind of cities , partially due to the UHI . Increases in heat within urban centers increases the length of growing seasons , and decreases the occurrence of weak tornadoes . The UHI decreases air quality by increasing the production of pollutants such as ozone , and decreases water quality as warmer waters flow into area streams and put stress on their ecosystems . Not all cities have a distinct urban heat island . Mitigation of the urban heat island effect can be accomplished through the use of green roofs and the use of lighter-colored surfaces in urban areas , which reflect more sunlight and absorb less heat . There are concerns raised about possible contribution from urban heat islands to global warming . Research on China and India indicates that urban heat island effect contributes to climate warming by about 30 % . On the other hand , one 1999 comparison between urban and rural areas proposed that the urban heat island effects have little influence on global mean temperature trends . Many studies reveal increases in the severity of the effect with the progress of climate change . |
2361 | Scientific_consensus_on_climate_change | "Unquestionably, the U.N. Intergovernmental Panel on Climate Change (IPCC) was formed to build the scientific case for humanity being the primary cause of global warming. | Scientific consensus on climate change There is currently a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports. Nearly all actively publishing climate scientists (97–98%) support the consensus on anthropogenic climate change, and the remaining 2% of contrarian studies either cannot be replicated or contain errors. |
863 | Ozone_depletion | The warmer the planet gets, the more ozone forms, and by mid-century, Americans will likely suffer a 70 percent increase in unhealthy ozone smog, the National Center for Atmospheric Research has projected. | Ozone depletion Ozone depletion describes two distinct but related phenomena observed since the late 1970s : a steady decline of about four percent in the total amount of ozone in Earth 's stratosphere ( the ozone layer ) , and a much larger springtime decrease in stratospheric ozone around Earth 's polar regions . The latter phenomenon is referred to as the ozone hole . In addition to these well-known stratospheric phenomena , there are also springtime polar tropospheric ozone depletion events . The details of polar ozone hole formation differ from that of mid-latitude thinning but the most important process in both is catalytic destruction of ozone by atomic halogens . The main source of these halogen atoms in the stratosphere is photodissociation of man-made halocarbon refrigerants , solvents , propellants , and foam-blowing agents ( chlorofluorocarbon ( CFCs ) , HCFCs , freons , halons ) . These compounds are transported into the stratosphere by winds after being emitted at the surface . Both types of ozone depletion were observed to increase as emissions of halocarbons increased . CFCs and other contributory substances are referred to as ozone-depleting substances ( ODS ) . Since the ozone layer prevents most harmful UVB wavelengths ( 280 -- 315 nm ) of ultraviolet light ( UV light ) from passing through the Earth 's atmosphere , observed and projected decreases in ozone generated worldwide concern , leading to adoption of the Montreal Protocol that bans the production of CFCs , halons , and other ozone-depleting chemicals such as carbon tetrachloride and trichloroethane . It is suspected that a variety of biological consequences such as increases in sunburn , skin cancer , cataracts , damage to plants , and reduction of plankton populations in the ocean 's photic zone may result from the increased UV exposure due to ozone depletion . |
180 | Calcium_carbonate | Reef material is calcium carbonate, which contains 44 per cent carbon dioxide. | Calcium carbonate Calcium carbonate is a chemical compound with the formula CaCO3 . It is a common substance found in rocks as the minerals calcite and aragonite ( most notably as limestone , which contains both of those minerals ) and is the main component of pearls and the shells of marine organisms , snails , and eggs . Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale . It is medicinally used as a calcium supplement or as an antacid , but excessive consumption can be hazardous . |
1570 | Human_impact_on_the_environment | Humans are too insignificant to affect global climate. | Human impact on the environment Human impact on the environment or anthropogenic impact on the environment includes impacts on biophysical environments , biodiversity , and other resources . The term anthropogenic designates an effect or object resulting from human activity . The term was first used in the technical sense by Russian geologist Alexey Pavlov , and was first used in English by British ecologist Arthur Tansley in reference to human influences on climax plant communities . The atmospheric scientist Paul Crutzen introduced the term `` Anthropocene '' in the mid-1970s . The term is sometimes used in the context of pollution emissions that are produced as a result of human activities but applies broadly to all major human impacts on the environment . |
1331 | Sea | More than half of the 44 studies selected for publication found that raised levels of CO2 had little or no impact on marine life, including crabs, limpets, sea urchins and sponges | Sea A sea is a large body of salt water that is surrounded in whole or in part by land . More broadly , `` the sea '' is the interconnected system of Earth 's salty , oceanic waters -- considered as one global ocean or as several principal oceanic divisions . The sea moderates Earth 's climate and has important roles in the water cycle , carbon cycle , and nitrogen cycle . Although the sea has been traveled and explored since prehistory , the modern scientific study of the sea -- oceanography -- dates broadly to the British Challenger expedition of the 1870s . The sea is conventionally divided into up to five large oceanic sections -- including the International Hydrographic Organization 's four named oceans ( the Atlantic , Pacific , Indian , and Arctic ) and the Southern Ocean ; smaller , second-order sections , such as the Mediterranean , are known as seas . Owing to the present state of continental drift , the Northern Hemisphere is now fairly equally divided between land and sea ( a ratio of about 2:3 ) but the South is overwhelmingly oceanic ( 1:4.7 ) . Salinity in the open ocean is generally in a narrow band around 3.5 % by mass , although this can vary in more landlocked waters , near the mouths of large rivers , or at great depths . About 85 % of the solids in the open sea are sodium chloride . Deep-sea currents are produced by differences in salinity and temperature . Surface currents are formed by the friction of waves produced by the wind and by tides , the changes in local sea level produced by the gravity of the Moon and Sun . The direction of all of these is governed by surface and submarine land masses and by the rotation of the Earth ( the Coriolis effect ) . Former changes in sea levels have left continental shelves , shallow areas in the sea close to land . These nutrient-rich waters teem with life , which provide humans with substantial supplies of food -- mainly fish , but also shellfish , mammals , and seaweed -- which are both harvested in the wild and farmed . The most diverse areas surround great tropical coral reefs . Whaling in the deep sea was once common but whales ' dwindling numbers prompted international conservation efforts and finally a moratorium on most commercial hunting . Oceanography has established that not all life is restricted to the sunlit surface waters : even under enormous depths and pressures , nutrients streaming from hydrothermal vents support their own unique ecosystem . Life may have started there and aquatic microbial mats are generally credited with the oxygenation of Earth 's atmosphere ; both plants and animals first evolved in the sea . The sea is an essential aspect of human trade , travel , mineral extraction , and power generation . This has also made it essential to warfare and left major cities exposed to earthquakes and volcanoes from nearby faults ; powerful tsunami waves ; and hurricanes , typhoons , and cyclones produced in the tropics . This importance and duality has affected human culture , from early sea gods to the epic poetry of Homer to the changes induced by the Columbian Exchange , from burial at sea to Basho 's haikus to hyperrealist marine art , and inspiring music ranging from the shanties in The Complaynt of Scotland to Rimsky-Korsakov 's `` The Sea and Sinbad 's Ship '' to A-mei 's `` Listen to the Sea '' . It is the scene of leisure activities including swimming , diving , surfing , and sailing . However , population growth , industrialization , and intensive farming have all contributed to present-day marine pollution . Atmospheric carbon dioxide is being absorbed in increasing amounts , lowering its pH in a process known as ocean acidification . The shared nature of the sea has made overfishing an increasing problem . |
2910 | Scientific_method | The authors seem to have jumped right into statistical analysis without proposing a physical mechanism that works. | Scientific method The scientific method is a body of techniques for investigating phenomena , acquiring new knowledge , or correcting and integrating previous knowledge . To be termed scientific , a method of inquiry is commonly based on empirical or measurable evidence subject to specific principles of reasoning . The Oxford Dictionaries Online define the scientific method as `` a method or procedure that has characterized natural science since the 17th century , consisting in systematic observation , measurement , and experiment , and the formulation , testing , and modification of hypotheses '' . Experiments need to be designed to test hypotheses . The most important part of the scientific method is the experiment . The scientific method is a continuous process , which usually begins with observations about the natural world . Human beings are naturally inquisitive , so they often come up with questions about things they see or hear and often develop ideas ( hypotheses ) about why things are the way they are . The best hypotheses lead to predictions that can be tested in various ways , including making further observations about nature . In general , the strongest tests of hypotheses come from carefully controlled and replicated experiments that gather empirical data . Depending on how well the tests match the predictions , the original hypothesis may require refinement , alteration , expansion or even rejection . If a particular hypothesis becomes very well supported a general theory may be developed . Although procedures vary from one field of inquiry to another , identifiable features are frequently shared in common between them . The overall process of the scientific method involves making conjectures ( hypotheses ) , deriving predictions from them as logical consequences , and then carrying out experiments based on those predictions . A hypothesis is a conjecture , based on knowledge obtained while formulating the question . The hypothesis might be very specific or it might be broad . Scientists then test hypotheses by conducting experiments . Under modern interpretations , a scientific hypothesis must be falsifiable , implying that it is possible to identify a possible outcome of an experiment that conflicts with predictions deduced from the hypothesis ; otherwise , the hypothesis can not be meaningfully tested . The purpose of an experiment is to determine whether observations agree with or conflict with the predictions derived from a hypothesis . Experiments can take place anywhere from a college lab to CERN 's Large Hadron Collider . There are difficulties in a formulaic statement of method , however . Though the scientific method is often presented as a fixed sequence of steps , it represents rather a set of general principles . Not all steps take place in every scientific inquiry ( or to the same degree ) , and are not always in the same order . Some philosophers and scientists have argued that there is no scientific method , such as Lee Smolin and Paul Feyerabend ( in his Against Method ) . Nola and Sankey remark that `` For some , the whole idea of a theory of scientific method is yester-year 's debate '' . |
71 | Solar_minimum | Cold weather to grip world as solar minimum to deepen, NASA says | Solar minimum Solar minimum is the period of least solar activity in the 11 year solar cycle of the sun . During this time , sunspot and solar flare activity diminishes , and often does not occur for days at a time . The date of the minimum is described by a smoothed average over 12 months of sunspot activity , so identifying the date of the solar minimum usually can only happen 6 months after the minimum takes place . Solar minima are not generally correlated with changes in climate but recent studies have shown a correlation with regional weather patterns . Solar minimum is contrasted with the solar maximum , where there may be hundreds of sunspots . |
1529 | Scientific_consensus_on_climate_change | Human activities (mainly greenhouse-gas emissions) are the dominant cause of the rapid warming since the middle 1900s (IPCC, 2013). | Scientific consensus on climate change There is currently a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports. Nearly all actively publishing climate scientists (97–98%) support the consensus on anthropogenic climate change, and the remaining 2% of contrarian studies either cannot be replicated or contain errors. |
2560 | Ice_age | In the 11,400 years since the end of the last Ice Age, sea level has risen at an average of 4 feet/century, though it is now rising much more slowly because very nearly all of the land-based ice that is at low enough latitudes and altitudes to melt has long since gone." | Ice age An ice age is a period of long-term reduction in the temperature of Earth 's surface and atmosphere , resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers . Within a long-term ice age , individual pulses of cold climate are termed `` glacial periods '' ( or alternatively `` glacials '' or `` glaciations '' or colloquially as `` ice age '' ) , and intermittent warm periods are called `` interglacials '' . In the terminology of glaciology , ice age implies the presence of extensive ice sheets in both northern and southern hemispheres . By this definition , we are in an interglacial period -- the Holocene -- of the ice age . The ice age began 2.6 million years ago at the start of the Pleistocene epoch , because the Greenland , Arctic , and Antarctic ice sheets still exist . |
555 | Kodiak_bear | In Alaska, brown bears are changing their feeding habits to eat elderberries that ripen earlier. | Kodiak bear The Kodiak bear ( Ursus arctos middendorffi ) , also known as the Kodiak brown bear , sometimes the Alaskan brown bear , inhabits the islands of the Kodiak Archipelago in southwest Alaska . Its Alutiiq name is taquka-aq . It is the largest recognized subspecies of brown bear , and one of the two largest bears alive today , the other being the polar bear . Physiologically , the Kodiak bear is very similar to the other brown bear subspecies , such as the mainland grizzly bear ( Ursus arctos horribilis ) and the now-extinct California grizzly bear ( U. a. californicus † ) , with the main difference being in size . While there is generally much variation in size between brown bears in different areas , most usually weigh between 115 and 360 kg ( 254 and 794 lb ) . The Kodiak bear , on the other hand , commonly reaches sizes of 300 to , and has even been known to exceed weights of 680 kg on occasion . Despite this large variation in size , the diet and lifestyle of the Kodiak bear does not differ greatly from that of other brown bears . Ever since the first humans arrived in Alaska over the Bering land bridge , encounters between people and Kodiak bears have occurred . Today , these encounters have become relatively more common as a result of the increase in the human population in the region . Such encounters have included the hunting of bears by humans for their fur or meat , and , less commonly , attacks by bears upon humans . More recently , as conservation efforts have become more commonplace , concerns over the sustenance and stability of the Kodiak bear population have arisen . The IUCN classifies Ursus arctos , the species to which the Kodiak belongs , as being of `` least concern '' in terms of endangerment or extinction . However , the IUCN does not differentiate between subspecies ; therefore , it is unknown whether the Kodiak bear population is as healthy as is stated . As a result , the Alaska Department of Fish and Game , along with , to a lesser extent , the United States Fish and Wildlife Service , closely monitors the number of bears hunted in the state . |
1598 | Global_warming | Adapting to global warming is cheaper than preventing it. | Global warming Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years . In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing . Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years . Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) , whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change . Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned . |
1773 | Global_dimming | The global trend is calculated from hundreds of CO2 measuring stations and confirmed by satellites. | Global dimming Global dimming is the gradual reduction in the amount of global direct irradiance at the Earth 's surface that was observed for several decades after the start of systematic measurements in the 1950s . The effect varies by location , but worldwide it has been estimated to be of the order of a 4 % reduction over the three decades from 1960 -- 1990 . However , after discounting an anomaly caused by the eruption of Mount Pinatubo in 1991 , a very slight reversal in the overall trend has been observed . Global dimming is thought to have been caused by an increase in particulates such as sulfate aerosols in the atmosphere due to human action . It has interfered with the hydrological cycle by reducing evaporation and may have reduced rainfall in some areas . Global dimming also creates a cooling effect that may have partially counteracted the effect of greenhouse gases on global warming . |
2845 | Soon_and_Baliunas_controversy | The original global temperature schematic which appeared in the IPCC First Assessment Report and seemed to show the Medieval Warm Period (MWP) hotter than Present was based on the central England temperature record, and ended in the 1950s. | Soon and Baliunas controversy The Soon and Baliunas controversy involved the publication in 2003 of a review study written by aerospace engineer Willie Soon and astronomer Sallie Baliunas in the journal Climate Research , which was quickly taken up by the G.W. Bush administration as a basis for amending the first Environmental Protection Agency Report on the Environment . The paper was strongly criticized by numerous scientists for its methodology and for its misuse of data from previously published studies , prompting concerns about the peer review process of the paper . The controversy resulted in the resignation of half of the editors of the journal and in the admission by its publisher Otto Kinne that the paper should not have been published as it was . |
1342 | Effects_of_global_warming | The worsening of tidal flooding in American coastal communities is largely a consequence of greenhouse gases from human activity, and the problem will grow far worse in coming decades, scientists reported Monday. | Effects of global warming The effects of global warming are the environmental and social changes caused ( directly or indirectly ) by human emissions of greenhouse gases . There is a scientific consensus that climate change is occurring , and that human activities are the primary driver . Many impacts of climate change have already been observed , including glacier retreat , changes in the timing of seasonal events ( e.g. , earlier flowering of plants ) , and changes in agricultural productivity . Future effects of climate change will vary depending on climate change policies and social development . The two main policies to address climate change are reducing human greenhouse gas emissions ( climate change mitigation ) and adapting to the impacts of climate change . Geoengineering is another policy option . Near-term climate change policies could significantly affect long-term climate change impacts . Stringent mitigation policies might be able to limit global warming ( in 2100 ) to around 2 ° C or below , relative to pre-industrial levels . Without mitigation , increased energy demand and extensive use of fossil fuels might lead to global warming of around 4 ° C. Higher magnitudes of global warming would be more difficult to adapt to , and would increase the risk of negative impacts . |
1981 | Lisa_P._Jackson | The EPA director under Obama said the Clean Power Initiative would have no effect on man-made CO2 emissions. | Lisa P. Jackson Lisa Perez Jackson ( born February 8 , 1962 ) is an American chemical engineer who served as the Administrator of the United States Environmental Protection Agency ( EPA ) from 2009 to 2013 . In May 2013 , it was announced that Jackson would be joining Apple Inc. as their environmental director . Born in Philadelphia , Pennsylvania , Jackson is a graduate of Tulane University and Princeton University . She began working as a staff-level engineer for the Environmental Protection Agency in 1987 ; later moving to the EPA 's regional office in New York City , where she spent the majority of her 16-year EPA career . She joined the New Jersey Department of Environmental Protection in 2002 , working as the assistant commissioner of compliance and enforcement and as the assistant commissioner for land use management . In 2006 , New Jersey Governor Jon Corzine appointed Jackson the state 's Commissioner of Environmental Protection . Jackson also briefly served as Corzine 's Chief of Staff in late 2008 . On December 15 , 2008 , the President-elect Barack Obama nominated Jackson as the Administrator of the Environmental Protection Agency , she was confirmed by the Senate and took office on January 23 , 2009 . During her tenure , Jackson oversaw stricter fuel efficiency standards ; the EPA 's response to the Deepwater Horizon oil spill ; authorized carbon dioxide as a public health threat , granting the EPA authority to set new regulations regarding CO2 emissions ; and laid out a failed plan to set stricter smog pollution limits by amending the National Ambient Air Quality Standards . In December 2012 , Jackson announced she would be stepping down as EPA Administrator , a move which took effect on February 15 , 2013 ; she was succeeded by Deputy Administrator Bob Perciasepe , who became Acting Administrator pending Senate confirmation of Gina McCarthy on July 18 , 2013 as a permanent successor . |
2049 | Climate_change_in_Australia | The Millennium Drought starting in 1997 and ending in 2010 was misinterpreted as a long term trend as a consequence of Climate Change. | Climate change in Australia Climate change has been a major issue in Australia since the beginning of the 21st century . In 2013 , the CSIRO released a report stating that Australia is becoming hotter , and that it will experience more extreme heat and longer fire seasons because of climate change . In 2014 , the Bureau of Meteorology released a report on the state of Australia 's climate that highlighted several key points , including the significant increase in Australia 's temperatures ( particularly night-time temperatures ) and the increasing frequency of bush fires , droughts and floods , which have all been linked to climate change . Since the beginning of the 20th century Australia has experienced an increase of nearly 1 ° C in average annual temperatures , with warming occurring at twice the rate over the past 50 years than in the previous 50 years . Recent climate events such as extremely high temperatures and widespread drought have focused government and public attention on the impacts of climate change in Australia . Rainfall in southwestern Australia has decreased by 10 -- 20 % since the 1970s , while southeastern Australia has also experienced a moderate decline since the 1990s . Rainfall patterns are expected to be problematic , as rain has become heavier and infrequent , as well as more common in summer rather than in winter , with little or no uptrend in rainfall in the Western Plateau and the Central Lowlands of Australia . Water sources in the southeastern areas of Australia have depleted due to increasing population in urban areas ( rising demand ) coupled with climate change factors such as persistent prolonged drought ( diminishing supply ) . At the same time , Australia continues to have the highest per capita greenhouse gas emissions . Temperatures in Australia have also risen dramatically since 1910 and nights have become warmer . A carbon tax was introduced in 2011 by the Gillard government in an effort to reduce the impact of climate change and despite some criticism , it successfully reduced Australia 's carbon dioxide emissions , with coal generation down 11 % since 2008 -- 09 . The subsequent Australian Government , elected in 2013 under then Prime Minister Tony Abbott was criticised for being `` in complete denial about climate change '' . Furthermore , the Abbott government repealed the carbon tax on 17 July 2014 in a heavily criticised move . The renewable energy target ( RET ) , launched in 2001 , was heavily modified under Abbott 's government . However , under the government of Malcolm Turnbull , Australia attended the 2015 United Nations Climate Change Conference and adopted the Paris Agreement . This agreement includes a review of emission reduction targets every 5 years from 2020 . The federal government and all state governments ( New South Wales , Victoria , Queensland , South Australia , Western Australia , Tasmania , Northern Territory and the Australian Capital Territory ) have explicitly recognised that climate change is being caused by greenhouse gas emissions , in conformity with the scientific opinion on climate change . Sectors of the population have campaigned against new coal mines and coal-fired power stations , reflecting concerns about the effects of global warming on Australia . The Garnaut Climate Change Review predicted that a net benefit to Australia may be derived by stabilising greenhouse gases in the atmosphere at 450ppm CO2 eq . The per-capita carbon footprint in Australia was rated 12th in the world by PNAS in 2011 , considerably large given the small population of the country . |
2152 | Venus | Venus doesn't have a runaway greenhouse effect | Venus Venus is the second planet from the Sun , orbiting it every 224.7 Earth days . It has the longest rotation period ( 243 days ) of any planet in the Solar System and rotates in the opposite direction to most other planets . It has no natural satellites . It is named after the Roman goddess of love and beauty . It is the second-brightest natural object in the night sky after the Moon , reaching an apparent magnitude of − 4.6 , bright enough to cast shadows at night and , though rare , occasionally be visible in broad daylight . Because Venus orbits within Earth 's orbit it is an inferior planet and never appears to venture far from the Sun ; its maximum angular distance from the Sun ( elongation ) is 47.8 ° . Venus is a terrestrial planet and is sometimes called Earth 's `` sister planet '' because of their similar size , mass , proximity to the Sun , and bulk composition . It is radically different from Earth in other respects . It has the densest atmosphere of the four terrestrial planets , consisting of more than 96 % carbon dioxide . The atmospheric pressure at the planet 's surface is 92 times that of Earth , or roughly the pressure found 900 m underwater on Earth . Venus is by far the hottest planet in the Solar System , with a mean surface temperature of 735 K , even though Mercury is closer to the Sun . Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid , preventing its surface from being seen from space in visible light . It may have had water oceans in the past , but these would have vaporized as the temperature rose due to a runaway greenhouse effect . The water has probably photodissociated , and the free hydrogen has been swept into interplanetary space by the solar wind because of the lack of a planetary magnetic field . Venus 's surface is a dry desertscape interspersed with slab-like rocks and is periodically resurfaced by volcanism . As one of the brightest objects in the sky , Venus has been a major fixture in human culture for as long as records have existed . It has been made sacred to gods of many cultures , and has been a prime inspiration for writers and poets as the `` morning star '' and `` evening star '' . Venus was the first planet to have its motions plotted across the sky , as early as the second millennium BC . As the closest planet to Earth , Venus has been a prime target for early interplanetary exploration . It was the first planet beyond Earth visited by a spacecraft ( Mariner 2 in 1962 ) , and the first to be successfully landed on ( by Venera 7 in 1970 ) . Venus 's thick clouds render observation of its surface impossible in visible light , and the first detailed maps did not emerge until the arrival of the Magellan orbiter in 1991 . Plans have been proposed for rovers or more complex missions , but they are hindered by Venus 's hostile surface conditions . |
1753 | Kevin_E._Trenberth | Trenberth is talking about the details of energy flow, not whether global warming is happening. | Kevin E. Trenberth Kevin Edward Trenberth ( born November 8 , 1944 ) is part of the Climate Analysis Section at the US NCAR National Center for Atmospheric Research . He was a lead author of the 2001 and 2007 IPCC Scientific Assessment of Climate Change ( see IPCC Fourth Assessment Report ) and serves on the Scientific Steering Group for the Climate Variability and Predictability ( CLIVAR ) program . He chaired the WCRP Observation and Assimilation Panel from 2004 to 2010 and chaired the Global Energy and Water Exchanges ( GEWEX ) scientific steering group from 2010-2013 ( member 2007-14 ) . In addition , he served on the Joint Scientific Committee of the World Climate Research Programme , and has made significant contributions to research into El Niño-Southern Oscillation . Kevin 's work is highly cited and he has an h-index of 100 ( 100 papers have over 100 citations ) . |
1426 | Coral_reef | Many of the world's coral reefs are already barren or in a state of constant decline. | Coral reef Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals . Coral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients . Most coral reefs are built from stony corals , which in turn consist of polyps that cluster in groups . The polyps belong to a group of animals known as Cnidaria , which also includes sea anemones and jellyfish . Unlike sea anemones , corals secrete hard carbonate exoskeletons which support and protect the coral polyps . Most reefs grow best in warm , shallow , clear , sunny and agitated waters . Often called `` rainforests of the sea '' , shallow coral reefs form some of the most diverse ecosystems on Earth . They occupy less than 0.1 % of the world 's ocean surface , about half the area of France , yet they provide a home for at least 25 % of all marine species , including fish , mollusks , worms , crustaceans , echinoderms , sponges , tunicates and other cnidarians . Paradoxically , coral reefs flourish even though they are surrounded by ocean waters that provide few nutrients . They are most commonly found at shallow depths in tropical waters , but deep water and cold water corals also exist on smaller scales in other areas . Coral reefs deliver ecosystem services to tourism , fisheries and shoreline protection . The annual global economic value of coral reefs is estimated between US$ 29.8-375 billion . However , coral reefs are fragile ecosystems , partly because they are very sensitive to water temperature . They are under threat from climate change , oceanic acidification , blast fishing , cyanide fishing for aquarium fish , sunscreen use , overuse of reef resources , and harmful land-use practices , including urban and agricultural runoff and water pollution , which can harm reefs by encouraging excess algal growth . |
2966 | Scientific_consensus_on_climate_change | Over the three years from 1979 to 1982 when CO2 emissions were decreasing due to the rapid increase in the price of oil that drastically reduced consumption, there was no change in the rate of increase in atmospheric concentration of CO2 proving that humans were not the primary source for the increase in concentration.' | Scientific consensus on climate change There is currently a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports. Nearly all actively publishing climate scientists (97–98%) support the consensus on anthropogenic climate change, and the remaining 2% of contrarian studies either cannot be replicated or contain errors. |
366 | United_Nations_in_popular_culture | Armed conflicts over resources may become a reality, and have the potential to escalate into nuclear war. | United Nations in popular culture Popular culture references to the United Nations have been made in several media , including film , books , video games , and others . In many instances , the United Nations ( or a fictional agency thereof ) will figure in a storyline . In the case of science fiction , for example , the humans are united under one government that is descended directly from the UN . |
1057 | Dead_zone_(ecology) | "Moreover, the ocean already contains so-called oxygen minimum zones, generally found in the middle depths. | Dead zone (ecology) Dead zones are hypoxic ( low-oxygen ) areas in the world 's oceans and large lakes , caused by `` excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water . ( NOAA ) . '' In the 1970s oceanographers began noting increased instances of dead zones . These occur near inhabited coastlines , where aquatic life is most concentrated . ( The vast middle portions of the oceans , which naturally have little life , are not considered `` dead zones '' . ) In March 2004 , when the recently established UN Environment Programme published its first Global Environment Outlook Year Book ( GEO Year Book 2003 ) , it reported 146 dead zones in the world 's oceans where marine life could not be supported due to depleted oxygen levels . Some of these were as small as a square kilometre ( 0.4 mi ² ) , but the largest dead zone covered 70,000 square kilometres ( 27,000 mi ² ) . A 2008 study counted 405 dead zones worldwide . |
356 | Human_extinction | This requires us to work towards avoiding catastrophic possibilities rather than looking at probabilities, as learning from mistakes is not an option when it comes to existential risks. | Human extinction In futures studies , human extinction is the hypothetical end of the human species . This may be caused by natural causes or it may be anthropogenic , i.e. the result of human action . The likelihood of human extinction in the near future by wholly natural scenarios , such as a meteorite impact or large-scale volcanism , is generally considered to be extremely low . For anthropogenic extinction , many possible scenarios have been proposed : Human global nuclear annihilation , biological warfare or the release of a pandemic-causing agent , dysgenics , overpopulation , ecological collapse , and global warming ; in addition , emerging technologies could bring about new extinction scenarios , such as advanced artificial intelligence , biotechnology or self-replicating nanobots . The probability of anthropogenic human extinction within the next hundred years is the topic of an active debate . Human extinction needs to be differentiated from the extinction of all life on Earth ( see also future of Earth ) and from the extinction of major components of human culture ( e.g. , through a global catastrophe leaving only small , scattered human populations , which might evolve in isolation ) . |
1722 | Greenhouse_gas | Humans are small but powerful, and human CO2 emissions are causing global warming. | Greenhouse gas A greenhouse gas ( abbrev . GHG ) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range . This process is the fundamental cause of the greenhouse effect . The primary greenhouse gases in Earth 's atmosphere are water vapor , carbon dioxide , methane , nitrous oxide , and ozone . Without greenhouse gases , the average temperature of Earth 's surface would be about -18 ° C , rather than the present average of 15 ° C . In the Solar System , the atmospheres of Venus , Mars and Titan also contain gases that cause a greenhouse effect . Human activities since the beginning of the Industrial Revolution ( taken as the year 1750 ) have produced a 40 % increase in the atmospheric concentration of carbon dioxide , from 280 ppm in 1750 to 406 ppm in early 2017 . This increase has occurred despite the uptake of a large portion of the emissions by various natural `` sinks '' involved in the carbon cycle . Anthropogenic carbon dioxide emissions ( i.e. , emissions produced by human activities ) come from combustion of fossil fuels , principally coal , oil , and natural gas , along with deforestation , soil erosion and animal agriculture . It has been estimated that if greenhouse gas emissions continue at the present rate , Earth 's surface temperature could exceed historical values as early as 2047 , with potentially harmful effects on ecosystems , biodiversity and the livelihoods of people worldwide . Recent estimates suggest that on the current emissions trajectory the Earth could pass a threshold of 2 ° C global warming , which the United Nations ' IPCC designated as the upper limit to avoid `` dangerous '' global warming , by 2036 . |
2123 | Temperature_record_of_the_past_1000_years | Tree-rings diverge from temperature after 1960 | Temperature record of the past 1000 years For information on the description of the Medieval Warm Period and Little Ice Age in various IPCC reports see MWP and LIA in IPCC reportsThe temperature record of the past 1,000 years is reconstructed using data from climate proxy records in conjunction with the modern instrumental temperature record which only covers the last 150 years at a global scale . Large-scale reconstructions covering part or all of the 1st millennium and 2nd millennium have shown that recent temperatures are exceptional : the Intergovernmental Panel on Climate Change Fourth Assessment Report of 2007 concluded that `` Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely '' the highest in at least the past 1,300 years . '' The curve shown in graphs of these reconstructions is widely known as the hockey stick graph because of the sharp increase in temperatures during the last century . As of 2010 this broad pattern was supported by more than two dozen reconstructions , using various statistical methods and combinations of proxy records , with variations in how flat the pre-20th-century `` shaft '' appears . Sparseness of proxy records results in considerable uncertainty for earlier periods . Individual proxy records , such as tree ring widths and densities used in dendroclimatology , are calibrated against the instrumental record for the period of overlap . Networks of such records are used to reconstruct past temperatures for regions : tree ring proxies have been used to reconstruct Northern Hemisphere extratropical temperatures ( within the tropics trees do not form rings ) but are confined to land areas and are scarce in the Southern Hemisphere which is largely ocean . Wider coverage is provided by multiproxy reconstructions , incorporating proxies such as lake sediments , ice cores and corals which are found in different regions , and using statistical methods to relate these sparser proxies to the greater numbers of tree ring records . The `` Composite Plus Scaling '' ( CPS ) method is widely used for large-scale multiproxy reconstructions of hemispheric or global average temperatures ; this is complemented by Climate Field Reconstruction ( CFR ) methods which show how climate patterns have developed over large spatial areas , making the reconstruction useful for investigating natural variability and long-term oscillations as well as for comparisons with patterns produced by climate models . During the 1,900 years before the 20th century , it is likely that the next warmest period was from 950 to 1100 , with peaks at different times in different regions . This has been called the Medieval Warm Period , and some evidence suggests widespread cooler conditions during a period around the 17th century known as the Little Ice Age . In the hockey stick controversy , contrarians have asserted that the Medieval Warm Period was warmer than at present , and have disputed the data and methods of climate reconstructions . |
9 | Carbon_dioxide | Ironic' study finds more CO2 has slightly cooled the planet | Carbon dioxide Carbon dioxide ( chemical formula ) is a colorless gas with a density about 60 % higher than that of air ( 1.225 g/L ) that is odorless at normally encountered concentrations . Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms . It occurs naturally in Earth 's atmosphere as a trace gas at a concentration of about 0.04 percent ( 400 ppm ) by volume . Natural sources include volcanoes , hot springs and geysers , and it is freed from carbonate rocks by dissolution in water and acids . Because carbon dioxide is soluble in water , it occurs naturally in groundwater , rivers and lakes , ice caps , glaciers and seawater . It is present in deposits of petroleum and natural gas . As the source of available carbon in the carbon cycle , atmospheric carbon dioxide is the primary carbon source for life on Earth and its concentration in Earth 's pre-industrial atmosphere since late in the Precambrian has been regulated by photosynthetic organisms and geological phenomena . Plants , algae and cyanobacteria use light energy to photosynthesize carbohydrate from carbon dioxide and water , with oxygen produced as a waste product . Carbon dioxide is produced by all aerobic organisms when they metabolize carbohydrates and lipids to produce energy by respiration . It is returned to water via the gills of fish and to the air via the lungs of air-breathing land animals , including humans . Carbon dioxide is produced during the processes of decay of organic materials and the fermentation of sugars in bread , beer and winemaking . It is produced by combustion of wood and other organic materials and fossil fuels such as coal , peat , petroleum and natural gas . It is a versatile industrial material , used , for example , as an inert gas in welding and fire extinguishers , as a pressurizing gas in air guns and oil recovery , as a chemical feedstock and in liquid form as a solvent in decaffeination of coffee and supercritical drying . It is added to drinking water and carbonated beverages including beer and sparkling wine to add effervescence . The frozen solid form of , known as `` dry ice '' is used as a refrigerant and as an abrasive in dry-ice blasting . Carbon dioxide is the most significant long-lived greenhouse gas in Earth 's atmosphere . Since the Industrial Revolution anthropogenic emissions - primarily from use of fossil fuels and deforestation - have rapidly increased its concentration in the atmosphere , leading to global warming . Carbon dioxide also causes ocean acidification because it dissolves in water to form carbonic acid . |
1634 | Sea_level_rise | Satellites measure Antarctica losing land ice at an accelerating rate. | Sea level rise A sea level rise is an increase in the volume of water in the world 's oceans , resulting in an increase in global mean sea level . Sea level rise is usually attributed to global climate change by thermal expansion of the water in the oceans and by melting of Ice sheets and glaciers on land . Melting of floating ice shelves or icebergs at sea raises sea levels only slightly . Sea level rise at specific locations may be more or less than the global average . Local factors might include tectonic effects , subsidence of the land , tides , currents , storms , etc. . Sea level rise is expected to continue for centuries . Because of the slow inertia , long response time for parts of the climate system , it has been estimated that we are already committed to a sea-level rise of approximately 2.3 m for each degree Celsius of temperature rise within the next 2,000 years . IPCC Summary for Policymakers , AR5 , 2014 , indicated that the global mean sea level rise will continue during the 21st century , very likely at a faster rate than observed from 1971 to 2010 . Projected rates and amounts vary . A January 2017 NOAA report suggests a range of GMSL rise of 0.3 -- 2.5 m possible during the 21st century . Sea level rises can considerably influence human populations in coastal and island regions and natural environments like marine ecosystems . |
2521 | Sun | The atmosphere of the Earth is less able to absorb shortwave radiation from the Sun than thermal radiation coming from the surface. | Sun The Sun is the star at the center of the Solar System . It is a nearly perfect sphere of hot plasma , with internal convective motion that generates a magnetic field via a dynamo process . It is by far the most important source of energy for life on Earth . Its diameter is about 109 times that of Earth , and its mass is about 330,000 times that of Earth , accounting for about 99.86 % of the total mass of the Solar System . About three quarters of the Sun 's mass consists of hydrogen ( ~ 73 % ) ; the rest is mostly helium ( ~ 25 % ) , with much smaller quantities of heavier elements , including oxygen , carbon , neon , and iron . The Sun is a G-type main-sequence star ( G2V ) based on its spectral class . As such , it is informally referred to as a yellow dwarf . It formed approximately 4.6 billionAll numbers in this article are short scale . One billion is 109 , or 1,000,000,000 . years ago from the gravitational collapse of matter within a region of a large molecular cloud . Most of this matter gathered in the center , whereas the rest flattened into an orbiting disk that became the Solar System . The central mass became so hot and dense that it eventually initiated nuclear fusion in its core . It is thought that almost all stars form by this process . The Sun is roughly middle-aged ; it has not changed dramatically for more than four billion years , and will remain fairly stable for more than another five billion years . After hydrogen fusion in its core has diminished to the point at which it is no longer in hydrostatic equilibrium , the core of the Sun will experience a marked increase in density and temperature while its outer layers expand to eventually become a red giant . It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus , and render Earth uninhabitable . The enormous effect of the Sun on Earth has been recognized since prehistoric times , and the Sun has been regarded by some cultures as a deity . The synodic rotation of Earth and its orbit around the Sun are the basis of the solar calendar , which is the predominant calendar in use today . |
477 | Deforestation_in_Indonesia | Scientists say halting deforestation 'just as urgent' as reducing emissions | Deforestation in Indonesia Deforestation in Indonesia involves the long-term loss of forests and foliage across much of the country ; it has had massive environmental and social impacts . Indonesia is home to some of the most biologically diverse forests in the world and ranks third in number of species behind Brazil and the Democratic Republic of Congo . As late as 1900 , Indonesia was still a densely forested country : forests represented 84 percent of the total land area . Deforestation intensified in the 1970s and has accelerated further since then . The estimated forest cover of 170 million hectares around 1900 decreased to less than 100 million hectares by the end of the 20th century . In 2008 , it was estimated that tropical rainforests in Indonesia would be logged out in a decade . Of the total logging in Indonesia , up to 80 % is reported to be performed illegally . Large areas of forest in Indonesia have been cleared by large multinational pulp companies , such as Asia Pulp and Paper , and replaced by plantations . Forests are often burned by farmers and plantation owners . Another major source of deforestation is the logging industry , driven by demand from China and Japan . Agricultural development and transmigration programs moved large populations into rainforest areas , further increasing deforestation rates . Logging and the burning of forests to clear land for cultivation has made Indonesia the world 's third largest emitter of greenhouse gases , behind China and the United States . Forest fires often destroy high capacity carbon sinks , including old-growth rainforest and peatlands . In May 2011 , Indonesia declared a moratorium on new logging contracts to help combat this . This appeared to be ineffective in the short-term , as the rate of deforestation continued to increase . By 2012 Indonesia had surpassed the rate of deforestation in Brazil , and become the fastest forest clearing nation in the world . |
2293 | Steve_McIntyre | Steve McIntyre noticed a strange discontinuity in US temperature data, occurring around January 2000. | Steve McIntyre Steven McIntyre ( born c. 1947 ) is a Canadian mining exploration company director , a former minerals prospector and semi-retired mining consultant whose work has included statistical analysis . He is best known as the founder and editor of Climate Audit , a blog devoted to the analysis and discussion of climate data . He is most prominent as a critic of the temperature record of the past 1000 years and the data quality of NASA 's Goddard Institute for Space Studies . He is known in particular for his statistical critique , with economist Ross McKitrick , of the hockey stick graph which appears to show that the increase in late 20th century global temperatures is unprecedented in the past 1,000 years . |
2997 | Ecosystem_ecology | The trend in CO2 at Mauna Loa is practically identical to the global trend because CO2 mixes well throughout the atmosphere. | Ecosystem ecology Ecosystem ecology is the integrated study of living ( biotic ) and non-living ( abiotic ) components of ecosystems and their interactions within an ecosystem framework . This science examines how ecosystems work and relates this to their components such as chemicals , bedrock , soil , plants , and animals . Ecosystem ecology examines physical and biological structures and examines how these ecosystem characteristics interact with each other . Ultimately , this helps us understand how to maintain high quality water and economically viable commodity production . A major focus of ecosystem ecology is on functional processes , ecological mechanisms that maintain the structure and services produced by ecosystems . These include primary productivity ( production of biomass ) , decomposition , and trophic interactions . Studies of ecosystem function have greatly improved human understanding of sustainable production of forage , fiber , fuel , and provision of water . Functional processes are mediated by regional-to-local level climate , disturbance , and management . Thus ecosystem ecology provides a powerful framework for identifying ecological mechanisms that interact with global environmental problems , especially global warming and degradation of surface water . This example demonstrates several important aspects of ecosystems : Ecosystem boundaries are often nebulous and may fluctuate in time Organisms within ecosystems are dependent on ecosystem level biological and physical processes Adjacent ecosystems closely interact and often are interdependent for maintenance of community structure and functional processes that maintain productivity and biodiversity These characteristics also introduce practical problems into natural resource management . Who will manage which ecosystem ? Will timber cutting in the forest degrade recreational fishing in the stream ? These questions are difficult for land managers to address while the boundary between ecosystems remains unclear ; even though decisions in one ecosystem will affect the other . We need better understanding of the interactions and interdependencies of these ecosystems and the processes that maintain them before we can begin to address these questions . Ecosystem ecology is an inherently interdisciplinary field of study . An individual ecosystem is composed of populations of organisms , interacting within communities , and contributing to the cycling of nutrients and the flow of energy . The ecosystem is the principal unit of study in ecosystem ecology . Population , community , and physiological ecology provide many of the underlying biological mechanisms influencing ecosystems and the processes they maintain . Flowing of energy and cycling of matter at the ecosystem level are often examined in ecosystem ecology , but , as a whole , this science is defined more by subject matter than by scale . Ecosystem ecology approaches organisms and abiotic pools of energy and nutrients as an integrated system which distinguishes it from associated sciences such as biogeochemistry . Biogeochemistry and hydrology focus on several fundamental ecosystem processes such as biologically mediated chemical cycling of nutrients and physical-biological cycling of water . Ecosystem ecology forms the mechanistic basis for regional or global processes encompassed by landscape-to-regional hydrology , global biogeochemistry , and earth system science . |
1971 | Renewable_energy | The carbon footprint on wind [energy] is significant. | Renewable energy Renewable energy is energy that is collected from renewable resources , which are naturally replenished on a human timescale , such as sunlight , wind , rain , tides , waves , and geothermal heat . Renewable energy often provides energy in four important areas : electricity generation , air and water heating/cooling , transportation , and rural ( off-grid ) energy services . Based on REN21 's 2016 report , renewables contributed 19.2 % to humans ' global energy consumption and 23.7 % to their generation of electricity in 2014 and 2015 , respectively . This energy consumption is divided as 8.9 % coming from traditional biomass , 4.2 % as heat energy ( modern biomass , geothermal and solar heat ) , 3.9 % hydro electricity and 2.2 % is electricity from wind , solar , geothermal , and biomass . Worldwide investments in renewable technologies amounted to more than US$ 286 billion in 2015 , with countries like China and the United States heavily investing in wind , hydro , solar and biofuels . Globally , there are an estimated 7.7 million jobs associated with the renewable energy industries , with solar photovoltaics being the largest renewable employer . As of 2015 worldwide , more than half of all new electricity capacity installed was renewable . Renewable energy resources exist over wide geographical areas , in contrast to other energy sources , which are concentrated in a limited number of countries . Rapid deployment of renewable energy and energy efficiency is resulting in significant energy security , climate change mitigation , and economic benefits . The results of a recent review of the literature concluded that as greenhouse gas ( GHG ) emitters begin to be held liable for damages resulting from GHG emissions resulting in climate change , a high value for liability mitigation would provide powerful incentives for deployment of renewable energy technologies . In international public opinion surveys there is strong support for promoting renewable sources such as solar power and wind power . At the national level , at least 30 nations around the world already have renewable energy contributing more than 20 percent of energy supply . National renewable energy markets are projected to continue to grow strongly in the coming decade and beyond . Some places and at least two countries , Iceland and Norway generate all their electricity using renewable energy already , and many other countries have the set a goal to reach 100 % renewable energy in the future . For example , in Denmark the government decided to switch the total energy supply ( electricity , mobility and heating/cooling ) to 100 % renewable energy by 2050 . While many renewable energy projects are large-scale , renewable technologies are also suited to rural and remote areas and developing countries , where energy is often crucial in human development . United Nations ' Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity . As most of renewables provide electricity , renewable energy deployment is often applied in conjunction with further electrification , which has several benefits : Electricity can be converted to heat ( where necessary generating higher temperatures than fossil fuels ) , can be converted into mechanical energy with high efficiency and is clean at the point of consumption . In addition to that electrification with renewable energy is much more efficient and therefore leads to a significant reduction in primary energy requirements , because most renewables do n't have a steam cycle with high losses ( fossil power plants usually have losses of 40 to 65 % ) . Renewable energy systems are rapidly becoming more efficient and cheaper . Their share of total energy consumption is increasing . Growth in consumption of coal and oil could end by 2020 due to increased uptake of renewables and natural gas . |
1815 | Neanderthal | Humans have been through climate changes before- but mostly cold ones and | Neanderthal Neanderthals , or more rarely Neandertals , ( -LSB- niˈændərˌtɑːl -RSB- , also -LSB- neɪ -RSB- - , - -LSB- ˈɑːndər -RSB- - , - -LSB- ˌtɔːl -RSB- , - -LSB- ˌθɔːl -RSB- named for the Neandertal region in Germany ) were a species or subspecies of archaic humans in the genus Homo that went extinct about 40,000 years ago . Neanderthals and modern humans share 99.7 % of their DNA and are hence closely related . ( By comparison , both modern humans and Neanderthals share 98.8 % of their DNA with their closest non-human living relatives , the chimpanzees . ) Neanderthals left bones and stone tools in Eurasia , from Western Europe to Central and Northern Asia . Fossil evidence suggests Neanderthals evolved in Europe , separate from modern humans in Africa for more than 400,000 years . They are considered either a distinct species , Homo neanderthalensis , or as a subspecies of Homo sapiens ( H. s. neanderthalensis ) . Hundreds of lithic assemblages were created by Neanderthals in Europe and Asia . Almost all of them are of the so-called Mousterian techno-complex , which begins c. 160,000 years ago when the makers started making fewer hand axes , and instead started to make tools out of flakes . Compared to modern humans , Neanderthals had a lower surface-to-volume ratio , with shorter legs and a bigger body , in conformance with Bergmann 's rule , as an energy-loss reduction adaptation to life in a high-latitude ( i.e. seasonally cold ) climate . Male Neanderthals had cranial capacities averaging 1600 cm3 , females 1300 cm3 , extending to 1736 cm3 in Amud 1 . This is notably larger than the 1250 to typical of modern humans . Males stood 164 to and females 152 to tall . The Neanderthal genome project published papers in 2010 and 2014 stating that Neanderthals contributed to the DNA of modern humans , including most humans outside sub-Saharan Africa , as well as a few populations in sub-Saharan Africa , through interbreeding , likely between 50,000 and 60,000 years ago . Recent studies also show that some Neanderthals mated with ancestors of modern humans long before the `` out of Africa migration '' of present day non-Africans , as early as 100,000 years ago . In 2016 , research indicated that there were three distinct episodes of interbreeding between modern humans and Neanderthals : the first encounter involved the ancestors of non-African modern humans , probably soon after leaving Africa ; the second , after the ancestral Melanesian group had branched off ( and subsequently had a unique episode of interbreeding with Denisovans ) ; and the third , involving the ancestors of East Asians only . Claims that Neanderthals deliberately buried their dead , and if they did , whether such burials had any symbolic meaning , are heavily contested . The debate on deliberate Neanderthal burials has been active since the 1908 discovery of the well-preserved Chapelle-aux-Saints 1 skeleton in a small hole in a cave in southwestern France . In this controversy 's most recent installment , a team of French researchers reinvestigated the Chapelle-aux-Saints cave and in January 2014 reasserted the century-old claim that the 1908 Neanderthal specimen had been deliberately buried , and this has in turn been heavily criticised . In 2013 , scientists sequenced the entire genome of a Neanderthal for the first time . The genome was extracted from the phalanx bone of a 50,000-year-old Neanderthal found in a Siberian cave . |
1445 | Electricity_sector_in_Argentina | CO2 emissions from all commercial operations in 2018 totaled 918 million metric tons—2.4% of global CO2 emissions from fossil fuel use. | Electricity sector in Argentina The electricity sector in Argentina constitutes the third largest power market in Latin America . It relies mostly on thermal generation ( 60 % of installed capacity ) and hydropower generation ( 36 % ) . The country still has a large untapped hydroelectric potential . The prevailing natural gas-fired thermal generation is at risk due to the uncertainty about future gas supply . Faced with rising electricity demand ( over 6 % annually ) and declining reserve margins , the government of Argentina is in the process of commissioning large projects , both in the generation and transmission sectors . To keep up with rising demand , it is estimated that about 1,000 MW of new generation capacity are needed each year . An important number of these projects are being financed by the government through trust funds , while independent private initiative is still limited as it has not fully recovered yet from the effects of the Argentine economic crisis . The electricity sector was unbundled in generation , transmission and distribution by the reforms carried out in the early 1990s . Generation occurs in a competitive and mostly liberalized market in which 75 % of the generation capacity is owned by private utilities . In contrast , the transmission and distribution sectors are highly regulated and much less competitive than generation . |
2029 | Climate_change_adaptation | Bill Gates claims pandemic's 'misery' will 'happen regularly' if climate change is not stopped | Climate change adaptation Climate change adaptation is a response to global warming and climate change , that seeks to reduce the vulnerability of social and biological systems to relatively sudden change and thus offset the effects of global warming . Even if emissions are stabilized relatively soon , global warming and its effects will last many years , and adaptation will be necessary to the resulting changes in climate . Adaptation is especially important in developing countries since those countries are predicted to bear the brunt of the effects of global warming . That is , the capacity and potential for humans to adapt ( called adaptive capacity ) is unevenly distributed across different regions and populations , and developing countries generally have less capacity to adapt ( Schneider et al. , 2007 ) . Furthermore , the degree of adaptation correlates to the situational focus on environmental issues . Therefore , adaptation requires the situational assessment of sensitivity and vulnerability to environmental impacts . Adaptive capacity is closely linked to social and economic development ( IPCC , 2007 ) . The economic costs of adaptation to climate change are likely to cost billions of dollars annually for the next several decades , though the amount of money needed is unknown . Donor countries promised an annual $ 100 billion by 2020 through the Green Climate Fund for developing countries to adapt to climate change . However , while the fund was set up during COP16 in Cancún , concrete pledges by developed countries have not been forthcoming . The adaptation challenge grows with the magnitude and the rate of climate change . Another response to climate change , known as climate change mitigation ( Verbruggen , 2007 ) is to reduce greenhouse gas ( GHG ) emissions and/or enhance the removal of these gases from the atmosphere ( through carbon sinks ) . Even the most effective reductions in emissions , however , would not prevent further climate change impacts , making the need for adaptation unavoidable ( Klein et al. , 2007 ) . In a literature assessment , Klein et al. ( 2007 ) assessed options for adaptation . They concluded , with very high confidence , that in the absence of mitigation efforts , the effects of climate change would reach such a magnitude as to make adaptation impossible for some natural ecosystems . Others are concerned that climate adaptation programs might interfere with the existing development programs and thus lead to unintended consequences for vulnerable groups . For human systems , the economic and social costs of unmitigated climate change would be very high . |
2580 | Hekla | Volcanoes emit around 0.3 billion tonnes of CO2 per year. | Hekla Hekla ( -LSB- 3 = Is-Hekla_pronunciation . ogg -RSB- ) , or Hecla , is a stratovolcano in the south of Iceland with a height of 1491 m. Hekla is one of Iceland 's most active volcanoes ; over 20 eruptions have occurred in and around the volcano since 874 . During the Middle Ages , Europeans called the volcano the `` Gateway to Hell '' . Hekla is part of a volcanic ridge , 40 km long . The most active part of this ridge , a fissure about 5.5 km long named Heklugjá , is considered to be the volcano Hekla proper . Hekla looks rather like an overturned boat , with its keel being a series of craters , two of which are generally the most active . The volcano 's frequent large eruptions have covered much of Iceland with tephra and these layers can be used to date eruptions of Iceland 's other volcanos . 10 % of the tephra created in Iceland in the last thousand years has come from Hekla , amounting to 5 km3 . The volcano has produced one of the largest volumes of lava of any in the world in the last millennium , around 8 km3 . |
1486 | Greenhouse_gas | So that means that probably about half, maybe half of that nine-tenths of the degree of total warming might be caused by greenhouse gases. | Greenhouse gas A greenhouse gas ( abbrev . GHG ) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range . This process is the fundamental cause of the greenhouse effect . The primary greenhouse gases in Earth 's atmosphere are water vapor , carbon dioxide , methane , nitrous oxide , and ozone . Without greenhouse gases , the average temperature of Earth 's surface would be about -18 ° C , rather than the present average of 15 ° C . In the Solar System , the atmospheres of Venus , Mars and Titan also contain gases that cause a greenhouse effect . Human activities since the beginning of the Industrial Revolution ( taken as the year 1750 ) have produced a 40 % increase in the atmospheric concentration of carbon dioxide , from 280 ppm in 1750 to 406 ppm in early 2017 . This increase has occurred despite the uptake of a large portion of the emissions by various natural `` sinks '' involved in the carbon cycle . Anthropogenic carbon dioxide emissions ( i.e. , emissions produced by human activities ) come from combustion of fossil fuels , principally coal , oil , and natural gas , along with deforestation , soil erosion and animal agriculture . It has been estimated that if greenhouse gas emissions continue at the present rate , Earth 's surface temperature could exceed historical values as early as 2047 , with potentially harmful effects on ecosystems , biodiversity and the livelihoods of people worldwide . Recent estimates suggest that on the current emissions trajectory the Earth could pass a threshold of 2 ° C global warming , which the United Nations ' IPCC designated as the upper limit to avoid `` dangerous '' global warming , by 2036 . |
901 | Exhaust_gas | CO2 is colorless, odorless and completely non-toxic. | Exhaust gas Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas , gasoline , petrol , biodiesel blends , diesel fuel , fuel oil , or coal . According to the type of engine , it is discharged into the atmosphere through an exhaust pipe , flue gas stack , or propelling nozzle . It often disperses downwind in a pattern called an exhaust plume . It is a major component of motor vehicle emissions ( and from stationary internal combustion engines ) , which can also include : Crankcase blow-by Evaporation of unused gasoline Motor vehicle emissions contribute to air pollution and are a major ingredient in the creation of smog in some large cities . A 2013 study by MIT indicates that 53,000 early deaths occur per year in the United States alone because of vehicle emissions . According to another study from the same university , traffic fumes alone cause the death of 5,000 people every year just in the United Kingdom . |
763 | Cyanobacteria | And some plants – like algae which use carbon for photosynthesis – may even benefit. | Cyanobacteria Cyanobacteria -LSB- saɪˌænoʊbækˈtɪəriə -RSB- , also known as Cyanophyta , is a phylum of bacteria that obtain their energy through photosynthesis , and are the only photosynthetic prokaryotes able to produce oxygen . The name `` cyanobacteria '' comes from the color of the bacteria ( κυανός ( kyanós ) = blue ) . Cyanobacteria used to be incorrectly called blue-green algae , but being prokaryotes , the term `` algae '' in modern usage refers to eukaryotes . Like other prokaryotes , cyanobacteria have no membrane-sheathed organelles . Photosynthesis is performed in distinctive folds in the outer membrane of the cell ( unlike green plants which use chloroplasts for this purpose ) . Biologists commonly agree that chloroplasts found in eukaryotes have their ancestry in cyanobacteria , via a process called endosymbiosis . By producing oxygen as a byproduct of photosynthesis , cyanobacteria are thought to have converted the early oxygen-poor , reducing atmosphere , into an oxidizing one , causing the `` rusting of the Earth '' and the Great Oxygenation Event , that dramatically changed the composition of life forms and led to the near-extinction of anaerobic organisms . Cyanobacteria are thought to eventually have evolved into plastids found in eukaryotic plants , which later differentiated into specialized organelles like the etioplast , leucoplast and the chloroplast . |
2522 | Earth | The effect of this disparity is that thermal radiation escaping to space comes mostly from the cold upper atmosphere, while the surface is maintained at a substantially warmer temperature. | Earth Earth ( from Eorðe -LSB- Γαῖα , Gaia -RSB- Terra ) , otherwise known as the World or the Globe , is the third planet from the Sun and the only object in the Universe known to harbor life . It is the densest planet in the Solar System and the largest of the four terrestrial planets . According to radiometric dating and other sources of evidence , Earth formed about 4.54 billion years ago . Earth 's gravity interacts with other objects in space , especially the Sun and the Moon , Earth 's only natural satellite . During one orbit around the Sun , Earth rotates about its axis over 365 times ; thus , an Earth year is about 365.26 days long . Earth 's axis of rotation is tilted , producing seasonal variations on the planet 's surface . The gravitational interaction between the Earth and Moon causes ocean tides , stabilizes the Earth 's orientation on its axis , and gradually slows its rotation . Earth 's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years . About 71 % of Earth 's surface is covered with water , mostly by its oceans . The remaining 29 % is land consisting of continents and islands that together have many lakes , rivers and other sources of water that contribute to the hydrosphere . The majority of Earth 's polar regions are covered in ice , including the Antarctic ice sheet and the sea ice of the Arctic ice pack . Earth 's interior remains active with a solid iron inner core , a liquid outer core that generates the Earth 's magnetic field , and a convecting mantle that drives plate tectonics . Within the first billion years of Earth 's history , life appeared in the oceans and began to affect the Earth 's atmosphere and surface , leading to the proliferation of aerobic and anaerobic organisms . Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago . Since then , the combination of Earth 's distance from the Sun , physical properties , and geological history have allowed life to evolve and thrive . In the history of the Earth , biodiversity has gone through long periods of expansion , occasionally punctuated by mass extinction events . Over 99 % of all species that ever lived on Earth are extinct . Estimates of the number of species on Earth today vary widely ; most species have not been described . Over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival . Humans have developed diverse societies and cultures ; politically , the world has about 200 sovereign states . |
267 | Bjerknes_Centre_for_Climate_Research | Yet a study published just this week, by the Bjerknes Centre for Climate Research in Bergen, Norway, found that the natural climate system can change abruptly, without the need for any external forces. | Bjerknes Centre for Climate Research The Bjerknes Centre for Climate Research is a climate research centre in Bergen , Norway . The centre has a special focus on Northern Europe and the Polar regions . The centre was started in 2000 and is a co-operation between University of Bergen , Institute of Marine Research , the Nansen Environmental and Remote Sensing Center and Uni Research . The centre was part of Research Council of Norway 's Centre of Excellence program from 2003 to 2013 . Eystein Jansen headed the centre from 2000 to 2013 , while Tore Furevik has been director since 2014 . Researchers from the Bjerknes Centre have taken part in the Intergovernmental Panel on Climate Change assessment reports ; Eystein Jansen as one of the lead authors in the fourth report and upcoming fifth report . It is named after Vilhelm Bjerknes and his son Jacob Bjerknes . |
2794 | Svante_Arrhenius | But his results are evidence that the actual climate sensitivity is about 3°C for a doubling of atmospheric CO2. | Svante Arrhenius Svante August Arrhenius ( 19 February 1859 -- 2 October 1927 ) was a Nobel-Prize winning Swedish scientist , originally a physicist , but often referred to as a chemist , and one of the founders of the science of physical chemistry . He received the Nobel Prize for Chemistry in 1903 , becoming the first Swedish Nobel laureate , and in 1905 became director of the Nobel Institute where he remained until his death . His lasting contributions to science are exemplified and memorialized by the Arrhenius equation , Arrhenius definition of an acid , lunar crater Arrhenius , the mountain of Arrheniusfjellet and the Arrhenius Labs at Stockholm University , all named after him . He was the first to use basic principles of physical chemistry to calculate estimates of the extent to which increases in atmospheric carbon dioxide increase Earth 's surface temperature through the Arrhenius effect , leading Keeling to conclude that human-caused carbon dioxide emissions are large enough to cause global warming . |
2897 | Antarctic_ice_sheet | A new article in Nature Geoscience describes an innovative approach employed to derive ice-mass changes from GRACE data. | Antarctic ice sheet The Antarctic ice sheet is one of the two polar ice caps of the Earth . It covers about 98 % of the Antarctic continent and is the largest single mass of ice on Earth . It covers an area of almost 14 e6km2 and contains 26.5 e6km3 of ice . Approximately 61 percent of all fresh water on the Earth is held in the Antarctic ice sheet , an amount equivalent to about 58 m of sea-level rise . In East Antarctica , the ice sheet rests on a major land mass , but in West Antarctica the bed can extend to more than 2,500 m below sea level . Much of the land in this area would be seabed if the ice sheet were not there . In contrast to the melting of the Arctic sea ice , sea ice around Antarctica was expanding . The reasons for this are not fully understood , but suggestions include the climatic effects on ocean and atmospheric circulation of the ozone hole , and/or cooler ocean surface temperatures as the warming deep waters melt the ice shelves . |
2374 | Global_warming | Water vapour is the most dominant greenhouse gas. | Global warming Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years . In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing . Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years . Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) , whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change . Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned . |
3134 | Global_warming | Over the last decade, heatwaves are five times more likely than if there had been no global warming. | Global warming Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years . In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing . Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years . Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) , whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change . Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned . |
138 | Human_overpopulation | As a result, half of the people surveyed around the world last year said they thought climate change would make humanity extinct. | Human overpopulation Human overpopulation occurs when the ecological footprint of a human population in a specific geographical location exceeds the carrying capacity of the place occupied by that group . Overpopulation can further be viewed , in a long term perspective , as existing when a population can not be maintained given the rapid depletion of non-renewable resources or given the degradation of the capacity of the environment to give support to the population . The term human overpopulation refers to the relationship between the entire human population and its environment : the Earth , or to smaller geographical areas such as countries . Overpopulation can result from an increase in births , a decline in mortality rates , an increase in immigration , or an unsustainable biome and depletion of resources . It is possible for very sparsely populated areas to be overpopulated if the area has a meagre or non-existent capability to sustain life ( e.g. a desert ) . Advocates of population moderation cite issues like quality of life , carrying capacity , and risk of starvation as a basis to argue against continuing high human population growth and for population decline . Scientists suggest that the human impact on the environment as a result of overpopulation , profligate consumption and proliferation of technology has pushed the planet into a new geological epoch known as the Anthropocene . |
2794 | Global_warming | But his results are evidence that the actual climate sensitivity is about 3°C for a doubling of atmospheric CO2. | Global warming Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years . In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing . Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years . Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) , whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change . Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned . |
512 | Greenhouse_gas | water vapour has been the main greenhouse gas and carbon dioxide has had a minuscule effect on global climate | Greenhouse gas A greenhouse gas ( abbrev . GHG ) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range . This process is the fundamental cause of the greenhouse effect . The primary greenhouse gases in Earth 's atmosphere are water vapor , carbon dioxide , methane , nitrous oxide , and ozone . Without greenhouse gases , the average temperature of Earth 's surface would be about -18 ° C , rather than the present average of 15 ° C . In the Solar System , the atmospheres of Venus , Mars and Titan also contain gases that cause a greenhouse effect . Human activities since the beginning of the Industrial Revolution ( taken as the year 1750 ) have produced a 40 % increase in the atmospheric concentration of carbon dioxide , from 280 ppm in 1750 to 406 ppm in early 2017 . This increase has occurred despite the uptake of a large portion of the emissions by various natural `` sinks '' involved in the carbon cycle . Anthropogenic carbon dioxide emissions ( i.e. , emissions produced by human activities ) come from combustion of fossil fuels , principally coal , oil , and natural gas , along with deforestation , soil erosion and animal agriculture . It has been estimated that if greenhouse gas emissions continue at the present rate , Earth 's surface temperature could exceed historical values as early as 2047 , with potentially harmful effects on ecosystems , biodiversity and the livelihoods of people worldwide . Recent estimates suggest that on the current emissions trajectory the Earth could pass a threshold of 2 ° C global warming , which the United Nations ' IPCC designated as the upper limit to avoid `` dangerous '' global warming , by 2036 . |
454 | Greenhouse_gas | Man-made greenhouse gases play only an insignificant role." | Greenhouse gas A greenhouse gas ( abbrev . GHG ) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range . This process is the fundamental cause of the greenhouse effect . The primary greenhouse gases in Earth 's atmosphere are water vapor , carbon dioxide , methane , nitrous oxide , and ozone . Without greenhouse gases , the average temperature of Earth 's surface would be about -18 ° C , rather than the present average of 15 ° C . In the Solar System , the atmospheres of Venus , Mars and Titan also contain gases that cause a greenhouse effect . Human activities since the beginning of the Industrial Revolution ( taken as the year 1750 ) have produced a 40 % increase in the atmospheric concentration of carbon dioxide , from 280 ppm in 1750 to 406 ppm in early 2017 . This increase has occurred despite the uptake of a large portion of the emissions by various natural `` sinks '' involved in the carbon cycle . Anthropogenic carbon dioxide emissions ( i.e. , emissions produced by human activities ) come from combustion of fossil fuels , principally coal , oil , and natural gas , along with deforestation , soil erosion and animal agriculture . It has been estimated that if greenhouse gas emissions continue at the present rate , Earth 's surface temperature could exceed historical values as early as 2047 , with potentially harmful effects on ecosystems , biodiversity and the livelihoods of people worldwide . Recent estimates suggest that on the current emissions trajectory the Earth could pass a threshold of 2 ° C global warming , which the United Nations ' IPCC designated as the upper limit to avoid `` dangerous '' global warming , by 2036 . |
1817 | Carbon_Pollution_Reduction_Scheme | Environment Minister Greg Hunt the Coalition's emissions reduction fund, at $13.95 per tonne of carbon, is around 1 per cent of the cost of reducing carbon under the former Labor government's carbon pricing scheme, which he cost $1,300 a tonne. | Carbon Pollution Reduction Scheme The Carbon Pollution Reduction Scheme ( or CPRS ) was a cap-and-trade emissions trading scheme for anthropogenic greenhouse gases proposed by the Rudd government , as part of its climate change policy , which had been due to commence in Australia in 2010 . It marked a major change in the energy policy of Australia . The policy began to be formulated in April 2007 , when the federal Labor Party was in Opposition and the six Labor-controlled states commissioned an independent review on energy policy , the Garnaut Climate Change Review , which published a number of reports . After Labor won the 2007 federal election and formed government , it published a Green Paper on climate change for discussion and comment . The Federal Treasury then modelled some of the financial and economic impacts of the proposed CPRS scheme . The Rudd government published a final White Paper on 15 December 2008 , and announced that legislation was intended to take effect in July 2010 ; but the legislation for the CPRS ( aka ETS ) failed to gain the numbers in the Senate and was twice rejected creating a double dissolution election trigger . A bitter political debate within the Coalition Opposition saw Opposition leader Malcolm Turnbull lose the leadership to the anti-CPRS Tony Abbott . The Rudd government did not call an election and in April 2010 , Rudd deferred plans for the CPRS . After the 2010 federal election , the Gillard Government was able to get the Carbon Pricing Mechanism ( CPM ) passed into law as part of the Clean Energy Futures Package ( CEF ) in 2011 , and became effective on 1 July 2012 . However , after the 2013 federal election there was a change in government , and the Abbott Government repealed the CEF package on 17 July 2014 . Due to the great deal of policy uncertainty surrounding the scheme , organizations in Australia responded in a rather informal and tepid manner and largely withheld from making any large-scale investments in emissions reductions technology during the scheme 's operation . |
77 | Proxima_Centauri | [S]unspot activity on the surface of our star has dropped to a new low. | Proxima Centauri Proxima Centauri or Alpha Centauri C is a red dwarf , a small low-mass star , about 4.25 light-years from the Sun in the constellation of Centaurus . It was discovered in 1915 by the Scottish astronomer Robert Innes , the Director of the Union Observatory in South Africa , and is the nearest-known star to the Sun . With an apparent magnitude of 11.05 , it is too faint to be seen with the naked eye . Proxima Centauri forms a third component of the Alpha Centauri binary star system , currently with a separation of about AU and an orbital period of 550,000 years . Because of Proxima Centauri 's proximity to Earth , its angular diameter can be measured directly . It is about one-seventh the diameter of the Sun . It has a mass about an eighth of the Sun 's mass , and its average density is about 40 times that of the Sun . Although it has a very low average luminosity , Proxima is a flare star that undergoes random dramatic increases in brightness because of magnetic activity . The star 's magnetic field is created by convection throughout the stellar body , and the resulting flare activity generates a total X-ray emission similar to that produced by the Sun . The mixing of the fuel at Proxima Centauri 's core through convection and its relatively low energy-production rate mean that it will be a main-sequence star for another four trillion years , or nearly 300 times the current age of the universe . In 2016 , the European Southern Observatory announced the discovery of Proxima b , a planet orbiting the star at a distance of roughly 0.05 AU with an orbital period of approximately 11.2 Earth days . Its estimated mass is at least 1.3 times that of the Earth . The equilibrium temperature of Proxima b is estimated to be within the range where water could exist as liquid on its surface , thus placing it within the habitable zone of Proxima Centauri , although because Proxima Centauri is a red dwarf and a flare star , whether it could support life is disputed . Previous searches for orbiting companions had ruled out the presence of brown dwarfs and supermassive planets . |
108 | Sea_level_rise | sea-level rise is not accelerating. | Sea level rise A sea level rise is an increase in the volume of water in the world 's oceans , resulting in an increase in global mean sea level . Sea level rise is usually attributed to global climate change by thermal expansion of the water in the oceans and by melting of Ice sheets and glaciers on land . Melting of floating ice shelves or icebergs at sea raises sea levels only slightly . Sea level rise at specific locations may be more or less than the global average . Local factors might include tectonic effects , subsidence of the land , tides , currents , storms , etc. . Sea level rise is expected to continue for centuries . Because of the slow inertia , long response time for parts of the climate system , it has been estimated that we are already committed to a sea-level rise of approximately 2.3 m for each degree Celsius of temperature rise within the next 2,000 years . IPCC Summary for Policymakers , AR5 , 2014 , indicated that the global mean sea level rise will continue during the 21st century , very likely at a faster rate than observed from 1971 to 2010 . Projected rates and amounts vary . A January 2017 NOAA report suggests a range of GMSL rise of 0.3 -- 2.5 m possible during the 21st century . Sea level rises can considerably influence human populations in coastal and island regions and natural environments like marine ecosystems . |
1866 | Earth | Climate scientists have predicted global temperatures would increase more than one degree Celsius by 2020," but observed temperatures have been only half as high. | Earth Earth ( from Eorðe -LSB- Γαῖα , Gaia -RSB- Terra ) , otherwise known as the World or the Globe , is the third planet from the Sun and the only object in the Universe known to harbor life . It is the densest planet in the Solar System and the largest of the four terrestrial planets . According to radiometric dating and other sources of evidence , Earth formed about 4.54 billion years ago . Earth 's gravity interacts with other objects in space , especially the Sun and the Moon , Earth 's only natural satellite . During one orbit around the Sun , Earth rotates about its axis over 365 times ; thus , an Earth year is about 365.26 days long . Earth 's axis of rotation is tilted , producing seasonal variations on the planet 's surface . The gravitational interaction between the Earth and Moon causes ocean tides , stabilizes the Earth 's orientation on its axis , and gradually slows its rotation . Earth 's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years . About 71 % of Earth 's surface is covered with water , mostly by its oceans . The remaining 29 % is land consisting of continents and islands that together have many lakes , rivers and other sources of water that contribute to the hydrosphere . The majority of Earth 's polar regions are covered in ice , including the Antarctic ice sheet and the sea ice of the Arctic ice pack . Earth 's interior remains active with a solid iron inner core , a liquid outer core that generates the Earth 's magnetic field , and a convecting mantle that drives plate tectonics . Within the first billion years of Earth 's history , life appeared in the oceans and began to affect the Earth 's atmosphere and surface , leading to the proliferation of aerobic and anaerobic organisms . Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago . Since then , the combination of Earth 's distance from the Sun , physical properties , and geological history have allowed life to evolve and thrive . In the history of the Earth , biodiversity has gone through long periods of expansion , occasionally punctuated by mass extinction events . Over 99 % of all species that ever lived on Earth are extinct . Estimates of the number of species on Earth today vary widely ; most species have not been described . Over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival . Humans have developed diverse societies and cultures ; politically , the world has about 200 sovereign states . |
2282 | Glacier | While there are isolated cases of growing glaciers, the overwhelming trend in glaciers worldwide is retreat. | Glacier A glacier ( -LSB- pronˈɡleɪʃər -RSB- or -LSB- ˈɡlæsiə -RSB- ) is a persistent body of dense ice that is constantly moving under its own weight ; it forms where the accumulation of snow exceeds its ablation ( melting and sublimation ) over many years , often centuries . Glaciers slowly deform and flow due to stresses induced by their weight , creating crevasses , seracs , and other distinguishing features . They also abrade rock and debris from their substrate to create landforms such as cirques and moraines . Glaciers form only on land and are distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water . On Earth , 99 % of glacial ice is contained within vast ice sheets in the polar regions , but glaciers may be found in mountain ranges on every continent except Australia , and on a few high-latitude oceanic islands . Between 35 ° N and 35 ° S , glaciers occur only in the Himalayas , Andes , Rocky Mountains , a few high mountains in East Africa , Mexico , New Guinea and on Zard Kuh in Iran . Glaciers cover about 10 percent of Earth 's land surface . Continental glaciers cover nearly 5 e6sqmi or about 98 percent of Antarctica 's 5.1 e6sqmi , with an average thickness of 7,000 ft. Greenland and Patagonia also have huge expanses of continental glaciers . Glacial ice is the largest reservoir of fresh water on Earth . Many glaciers from temperate , alpine and seasonal polar climates store water as ice during the colder seasons and release it later in the form of meltwater as warmer summer temperatures cause the glacier to melt , creating a water source that is especially important for plants , animals and human uses when other sources may be scant . Within high altitude and Antarctic environments , the seasonal temperature difference is often not sufficient to release meltwater . Because glacial mass is affected by long-term climatic changes , e.g. , precipitation , mean temperature , and cloud cover , glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level . A large piece of compressed ice , or a glacier , appears blue as large quantities of water appear blue . This is because water molecules absorb other colors more efficiently than blue . The other reason for the blue color of glaciers is the lack of air bubbles . Air bubbles , which give a white color to ice , are squeezed out by pressure increasing the density of the created ice . |
503 | Winter_1985_cold_wave | "During the sunless winter, a heatwave raised concerns that the polar vortex may be eroding. | Winter 1985 cold wave The Winter 1985 cold wave was a meteorological event , the result of the shifting of the polar vortex further south than is normally seen . Blocked from its normal movement , polar air from the north pushed into nearly every section of the eastern half of the United States and Canada , shattering record lows in a number of areas . The event was preceded by unusually warm weather in the eastern U.S. in December 1984 , suggesting that there was a build-up of cold air that was suddenly released from the Arctic , a meteorological event known as a Mobile Polar High , a weather process identified by Professor Marcel Leroux . |
2508 | Climate_variability | "The Pacific Decadal Oscillation (PDO) is a temperature pattern in the Pacific Ocean that spends roughly 20-30 years in the cool phase or the warm phase. | Climate variability Climate variability includes all the variations in the climate that last longer than individual weather events, whereas the term climate change only refers to those variations that persist for a longer period of time, typically decades or more. In the time since the industrial revolution the climate has increasingly been affected by human activities that are causing global warming and climate change.The climate system receives nearly all of its energy from the sun. The climate system also radiates energy to outer space. The balance of incoming and outgoing energy, and the passage of the energy through the climate system, determines Earth's energy budget. When the incoming energy is greater than the outgoing energy, earth's energy budget is positive and the climate system is warming. If more energy goes out, the energy budget is negative and earth experiences cooling. The energy moving through Earth's climate system finds expression in weather, varying on geographic scales and time. Long-term averages and variability of weather in a region constitute the region's climate. Such changes can be the result of "internal variability", when natural processes inherent to the various parts of the climate system alter the distribution of energy. Examples include variability in ocean basins such as the Pacific decadal oscillation and Atlantic multidecadal oscillation. Climate variability can also result from external forcing, when events outside of the climate system's components nonetheless produce changes within the system. Examples include changes in solar output and volcanism. Climate variability has consequences for sea level changes, plant life, and mass extinctions; it also affects human societies. |
2142 | Cross-correlation | Soares finds lack of correlation between CO2 and temperature | Cross-correlation In signal processing , cross-correlation is a measure of similarity of two series as a function of the displacement of one relative to the other . This is also known as a sliding dot product or sliding inner-product . It is commonly used for searching a long signal for a shorter , known feature . It has applications in pattern recognition , single particle analysis , electron tomography , averaging , cryptanalysis , and neurophysiology . For continuous functions f and g , the cross-correlation is defined as : where denotes the complex conjugate of , and is the displacement , also known as lag , although a positive value of actually means that leads . Similarly , for discrete functions , the cross-correlation is defined as : The cross-correlation is similar in nature to the convolution of two functions . In an autocorrelation , which is the cross-correlation of a signal with itself , there will always be a peak at a lag of zero , and its size will be the signal energy . In probability and statistics , the term cross-correlations is used for referring to the correlations between the entries of two random vectors X and Y , while the correlations of a random vector X are considered to be the correlations between the entries of X itself , those forming the correlation matrix ( matrix of correlations ) of X . If each of X and Y is a scalar random variable which is realized repeatedly in temporal sequence ( a time series ) , then the correlations of the various temporal instances of X are known as autocorrelations of X , and the cross-correlations of X with Y across time are temporal cross-correlations . Furthermore , in probability and statistics the definition of correlation always includes a standardising factor in such a way that correlations have values between − 1 and +1 . If and are two independent random variables with probability density functions f and g , respectively , then the probability density of the difference is formally given by the cross-correlation ( in the signal-processing sense ) ; however this terminology is not used in probability and statistics . In contrast , the convolution ( equivalent to the cross-correlation of f ( t ) and g ( − t ) ) gives the probability density function of the sum . |
1255 | Retreat_of_glaciers_since_1850 | the first scientists to show that the thick icecap that once covered the Arctic ocean was beginning to thin and shrink. | Retreat of glaciers since 1850 The retreat of glaciers since 1850 affects the availability of fresh water for irrigation and domestic use , mountain recreation , animals and plants that depend on glacier-melt , and , in the longer term , the level of the oceans . Studied by glaciologists , the temporal coincidence of glacier retreat with the measured increase of atmospheric greenhouse gases is often cited as an evidentiary underpinning of global warming . Mid-latitude mountain ranges such as the Himalayas , Alps , Rocky Mountains , Cascade Range , and the southern Andes , as well as isolated tropical summits such as Mount Kilimanjaro in Africa , are showing some of the largest proportionate glacial losses . Glacier mass balance is the key determinant of the health of a glacier . If the amount of frozen precipitation in the accumulation zone exceeds the quantity of glacial ice lost due to melting or in the ablation zone a glacier will advance ; if the accumulation is less than the ablation , the glacier will retreat . Glaciers in retreat will have negative mass balances , and if they do not find an equilibrium between accumulation and ablation , will eventually disappear . The Little Ice Age was a period from about 1550 to 1850 when the world experienced relatively cooler temperatures compared to the present . Subsequently , until about 1940 , glaciers around the world retreated as the climate warmed substantially . Glacial retreat slowed and even reversed temporarily , in many cases , between 1950 and 1980 as global temperatures cooled slightly . Since 1980 , a significant global warming has led to glacier retreat becoming increasingly rapid and ubiquitous , so much so that some glaciers have disappeared altogether , and the existences of many of the remaining glaciers are threatened . In locations such as the Andes of South America and Himalayas in Asia , the demise of glaciers in these regions has the potential to affect water supplies in those areas . The retreat of mountain glaciers , notably in western North America , Asia , the Alps and tropical and subtropical regions of South America , Africa and Indonesia , provide evidence for the rise in global temperatures since the late 19th century . The acceleration of the rate of retreat since 1995 of key outlet glaciers of the Greenland and West Antarctic ice sheets may foreshadow a rise in sea level , which would affect coastal regions . |
132 | Effects_of_global_warming | Climate change is not making natural disasters worse | Effects of global warming The effects of global warming are the environmental and social changes caused ( directly or indirectly ) by human emissions of greenhouse gases . There is a scientific consensus that climate change is occurring , and that human activities are the primary driver . Many impacts of climate change have already been observed , including glacier retreat , changes in the timing of seasonal events ( e.g. , earlier flowering of plants ) , and changes in agricultural productivity . Future effects of climate change will vary depending on climate change policies and social development . The two main policies to address climate change are reducing human greenhouse gas emissions ( climate change mitigation ) and adapting to the impacts of climate change . Geoengineering is another policy option . Near-term climate change policies could significantly affect long-term climate change impacts . Stringent mitigation policies might be able to limit global warming ( in 2100 ) to around 2 ° C or below , relative to pre-industrial levels . Without mitigation , increased energy demand and extensive use of fossil fuels might lead to global warming of around 4 ° C. Higher magnitudes of global warming would be more difficult to adapt to , and would increase the risk of negative impacts . |
1477 | Global_warming_controversy | Human-produced carbon might be one of the factors of climate change, but there's simply no evidence that it is a significant one. | Global warming controversy The global warming controversy concerns the public debate over whether global warming is occurring , how much has occurred in modern times , what has caused it , what its effects will be , whether any action should be taken to curb it , and if so what that action should be . In the scientific literature , there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases . No scientific body of national or international standing disagrees with this view , though a few organizations with members in extractive industries hold non-committal positions . Disputes over the key scientific facts of global warming are more prevalent in the media than in the scientific literature , where such issues are treated as resolved , and such disputes are more prevalent in the United States than globally . Political and popular debate concerning the existence and cause of climate change includes the reasons for the increase seen in the instrumental temperature record , whether the warming trend exceeds normal climatic variations , and whether human activities have contributed significantly to it . Scientists have resolved these questions decisively in favour of the view that the current warming trend exists and is ongoing , that human activity is the cause , and that it is without precedent in at least 2000 years . Public disputes that also reflect scientific debate include estimates of how responsive the climate system might be to any given level of greenhouse gases ( climate sensitivity ) , how global climate change will play out at local and regional scales , and what the consequences of global warming will be . Global warming remains an issue of widespread political debate , often split along party political lines , especially in the United States . Many of the issues that are settled within the scientific community , such as human responsibility for global warming , remain the subject of politically or economically motivated attempts to downplay , dismiss or deny them -- an ideological phenomenon categorised by academics and scientists as climate change denial . The sources of funding for those involved with climate science -- both supporting and opposing mainstream scientific positions -- have been questioned by both sides . There are debates about the best policy responses to the science , their cost-effectiveness and their urgency . Climate scientists , especially in the United States , have reported official and oil-industry pressure to censor or suppress their work and hide scientific data , with directives not to discuss the subject in public communications . Legal cases regarding global warming , its effects , and measures to reduce it have reached American courts . The fossil fuels lobby has been identified as overtly or covertly supporting efforts to undermine or discredit the scientific consensus on global warming . |
2290 | Cosmic_ray | Hypothetically, an increasing solar magnetic field could deflect galactic cosmic rays, which hypothetically seed low-level clouds, thus decreasing the Earth's reflectivity and causing global warming. | Cosmic ray Cosmic rays are high-energy radiation , mainly originating outside the Solar System . Upon impact with the Earth 's atmosphere , cosmic rays can produce showers of secondary particles that sometimes reach the surface . Composed primarily of high-energy protons and atomic nuclei , they are of mysterious origin . Data from the Fermi Space Telescope ( 2013 ) have been interpreted as evidence that a significant fraction of primary cosmic rays originate from the supernovae explosions of stars . Active galactic nuclei probably also produce cosmic rays . |
377 | Atmosphere_of_Earth | If we halve the carbon dioxide content of the atmosphere, all life dies. | Atmosphere of Earth The atmosphere of Earth is the layer of gases , commonly known as air , that surrounds the planet Earth and is retained by Earth 's gravity . The atmosphere of Earth protects life on Earth by absorbing ultraviolet solar radiation , warming the surface through heat retention ( greenhouse effect ) , and reducing temperature extremes between day and night ( the diurnal temperature variation ) . By volume , dry air contains 78.09 % nitrogen , 20.95 % oxygen , 0.93 % argon , 0.04 % carbon dioxide , and small amounts of other gases . Air also contains a variable amount of water vapor , on average around 1 % at sea level , and 0.4 % over the entire atmosphere . Air content and atmospheric pressure vary at different layers , and air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is found only in Earth 's troposphere and in artificial atmospheres . The atmosphere has a mass of about 5.15 kg , three quarters of which is within about 11 km of the surface . The atmosphere becomes thinner and thinner with increasing altitude , with no definite boundary between the atmosphere and outer space . The Kármán line , at 100 km , or 1.57 % of Earth 's radius , is often used as the border between the atmosphere and outer space . Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km . Several layers can be distinguished in the atmosphere , based on characteristics such as temperature and composition . The study of Earth 's atmosphere and its processes is called atmospheric science ( aerology ) . Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann . |
2912 | Climate | temperature under the ice is fixed at -2C. Thus elevated winter air temperatures | Climate Climate is the statistics of weather , usually over a 30-year interval . It is measured by assessing the patterns of variation in temperature , humidity , atmospheric pressure , wind , precipitation , atmospheric particle count and other meteorological variables in a given region over long periods of time . Climate differs from weather , in that weather only describes the short-term conditions of these variables in a given region . A region 's climate is generated by the climate system , which has five components : atmosphere , hydrosphere , cryosphere , lithosphere , and biosphere . The climate of a location is affected by its latitude , terrain , and altitude , as well as nearby water bodies and their currents . Climates can be classified according to the average and the typical ranges of different variables , most commonly temperature and precipitation . The most commonly used classification scheme was the Köppen climate classification . The Thornthwaite system , in use since 1948 , incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it . The Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region . Paleoclimatology is the study of ancient climates . Since direct observations of climate are not available before the 19th century , paleoclimates are inferred from proxy variables that include non-biotic evidence such as sediments found in lake beds and ice cores , and biotic evidence such as tree rings and coral . Climate models are mathematical models of past , present and future climates . Climate change may occur over long and short timescales from a variety of factors ; recent warming is discussed in global warming . Global warming results in redistributions . For example , `` a 3 ° C change in mean annual temperature corresponds to a shift in isotherms of approximately 300 -- 400 km in latitude ( in the temperate zone ) or 500 m in elevation . Therefore , species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones '' . |
2445 | 20th_century | When all forcings are combined, they show good correlation to global temperature throughout the 20th century including the mid-century cooling period. | 20th century The 20th century was a century that began on January 1 , 1901 and ended on December 31 , 2000 . It was the tenth and final century of the 2nd millennium . It is distinct from the century known as the 1900s which began on January 1 , 1900 , and ended on December 31 , 1999 . The 20th century was dominated by a chain of events that heralded significant changes in world history as to redefine the era : World War I and World War II , nuclear power and space exploration , nationalism and decolonization , the Cold War and post-Cold War conflicts ; intergovernmental organizations and cultural homogenization through developments in emerging transportation and communications technology ; poverty reduction and world population growth , awareness of environmental degradation , ecological extinction ; and the birth of the Digital Revolution . It saw great advances in communication and medical technology that by the late 1980s allowed for near-instantaneous worldwide computer communication and genetic modification of life . The term `` short twentieth century '' was coined to represent the events from 1914 to 1991 . Global total fertility rates , sea level rise and ecological collapses increased ; the resulting competition for land and dwindling resources accelerated deforestation , water depletion . and the mass extinction of half the world 's estimated nine million unique species and wildlife population ; consequences which are now being dealt with . It took all of human history up to 1804 for the world 's population to reach 1 billion ; world population reached an estimated 2 billion in 1927 ; by late 1999 , the global population reached 6 billion . Global literacy averaged 80 % ; global lifespan-averages exceeded 40 + years for the first time in history , with over half achieving 70 + years ( three decades longer than it was a century ago ) . |
2502 | Theory | Fundamental physics and global climate models both make testable predictions as to how the global climate should change in response to anthropogenic warming. | Theory A theory is a contemplative and rational type of abstract or generalizing thinking , or the results of such thinking . Depending on the context , the results might , for example , include generalized explanations of how nature works . The word has its roots in ancient Greek , but in modern use it has taken on several different related meanings . Theories guide the enterprise of finding facts rather than of reaching goals , and are neutral concerning alternatives among values . A theory can be a body of knowledge , which may or may not be associated with particular explanatory models . To theorize is to develop this body of knowledge . As already in Aristotle 's definitions , theory is very often contrasted to `` practice '' ( from Greek praxis , πρᾶξις ) a Greek term for doing , which is opposed to theory because pure theory involves no doing apart from itself . A classical example of the distinction between `` theoretical '' and `` practical '' uses the discipline of medicine : medical theory involves trying to understand the causes and nature of health and sickness , while the practical side of medicine is trying to make people healthy . These two things are related but can be independent , because it is possible to research health and sickness without curing specific patients , and it is possible to cure a patient without knowing how the cure worked . It is possible to distinguish between three types of theories . Explanatory theory , also known as descriptive or empirical , helps to explain why and under what conditions , certain situations take place . The second type is interpretive theory or constitutive theory and this imposes meaning on events and issues with the objective to understand , instead of explaining , the world . The last one is called normative theory , also referred to as prescriptive , which prescribes values and standards of conduct : that means dealing with how the world should be instead of what it is . In modern science , the term `` theory '' refers to scientific theories , a well-confirmed type of explanation of nature , made in a way consistent with scientific method , and fulfilling the criteria required by modern science . Such theories are described in such a way that any scientist in the field is in a position to understand and either provide empirical support ( `` verify '' ) or empirically contradict ( `` falsify '' ) it . Scientific theories are the most reliable , rigorous , and comprehensive form of scientific knowledge , in contrast to more common uses of the word `` theory '' that imply that something is unproven or speculative ( which is better characterized by the word ` hypothesis ' ) . Scientific theories are distinguished from hypotheses , which are individual empirically testable conjectures , and from scientific laws , which are descriptive accounts of how nature behaves under certain conditions . |
1539 | CLOUD_experiment | Climate change is due to cosmic rays. | CLOUD experiment Cosmics Leaving Outdoor Droplets or CLOUD is an experiment being run at CERN by a group of researchers led by Jasper Kirkby to investigate the microphysics between galactic cosmic rays ( GCRs ) and aerosols under controlled conditions . The experiment began operation in November 2009 . The primary goal is to understand the influence of galactic cosmic rays ( GCRs ) on aerosols and clouds , and their implications for climate . Although its design is optimised to address the cosmic ray question , ( as posed by Henrik Svensmark and colleagues in 1997 ) CLOUD allows as well to measure aerosol nucleation and growth under controlled laboratory conditions . Atmospheric aerosols and their effect on clouds are recognised by the IPCC as main source of uncertainty in present radiative forcing and climate models . |
549 | Hurricane_Harvey | The extent of climate change's influence on the jet stream is an intense subject of research. | Hurricane Harvey The name Harvey has been used for five tropical cyclones in the Atlantic Ocean . Hurricane Harvey ( 1981 ) - threatened Bermuda but turned away before striking , no damage . Hurricane Harvey ( 1993 ) - short-lived storm that threatened no land . Tropical Storm Harvey ( 1999 ) - struck Florida , causing $ 15 million in damage . Tropical Storm Harvey ( 2005 ) - earliest eighth-storm formation in the Atlantic Ocean since record-keeping began , breaking the old record set in 1936 by 12 days . Threatened Bermuda . Tropical Storm Harvey ( 2011 ) - record eighth-storm failing to reach hurricane strength , in a single season , since reliable records began . Strong tropical storm that affected parts of Central America . Category : Atlantic hurricane disambiguation pages |
1116 | Global_storm_activity_of_2010 | Severe 'snowmageddon' winters are now strongly linked to soaring polar temperatures, say researchers, with deadly summer heatwaves and torrential floods also probably linked. | Global storm activity of 2010 The global storm activity of 2010 includes major meteorological events in the Earth 's atmosphere during the year , including winter storms ( blizzards , ice storms , European windstorms ) , hailstorms , out of season monsoon rain storms , extratropical cyclones , gales , microbursts , flooding , rainstorms , tropical cyclones , and other severe weather events . The thunderstorm season for the Northern Hemisphere began this time of year , beginning on March 1 , and ending on August 31 . |
742 | Climate_change_and_agriculture | Global human emissions are only 3 per cent of total annual emissions. | Climate change and agriculture -RSB- Climate change and agriculture are interrelated processes , both of which take place on a global scale . Climate change affects agriculture in a number of ways , including through changes in average temperatures , rainfall , and climate extremes ( e.g. , heat waves ) ; changes in pests and diseases ; changes in atmospheric carbon dioxide and ground-level ozone concentrations ; changes in the nutritional quality of some foods ; and changes in sea level . Climate change is already affecting agriculture , with effects unevenly distributed across the world . Future climate change will likely negatively affect crop production in low latitude countries , while effects in northern latitudes may be positive or negative . Climate change will probably increase the risk of food insecurity for some vulnerable groups , such as the poor . Agriculture contributes to climate change by ( 1 ) anthropogenic emissions of greenhouse gases ( GHGs ) , and ( 2 ) by the conversion of non-agricultural land ( e.g. , forests ) into agricultural land . Agriculture , forestry and land-use change contributed around 20 to 25 % to global annual emissions in 2010 . There are a range of policies that can reduce the risk of negative climate change impacts on agriculture , and to reduce GHG emissions from the agriculture sector . |
2289 | Mercury_(planet) | In fact, in recent years when cosmic rays should have been having their largest cooling effect on record, temperatures have been at their highest on record. | Mercury (planet) Mercury is the smallest and innermost planet in the Solar System . Its orbital period around the Sun of 88 days is the shortest of all the planets in the Solar System . It is named after the Roman deity Mercury , the messenger to the gods . Like Venus , Mercury orbits the Sun within Earth 's orbit as an inferior planet , so it can only be seen visually in the morning or the evening sky , and never exceeds 28 ° away from the Sun . Also , like Venus and the Moon , the planet displays the complete range of phases as it moves around its orbit relative to Earth . Seen from Earth , this cycle of phases reoccurs approximately every 116 days , the so-called synodic period . Although Mercury can appear as a bright star-like object when viewed from Earth , its proximity to the Sun often makes it more difficult to see than Venus . Mercury is tidally or gravitationally locked with the Sun in a 3:2 resonance , and rotates in a way that is unique in the Solar System . As seen relative to the fixed stars , it rotates on its axis exactly three times for every two revolutions it makes around the Sun . As seen from the Sun , in a frame of reference that rotates with the orbital motion , it appears to rotate only once every two Mercurian years . An observer on Mercury would therefore see only one day every two years . Mercury 's axis has the smallest tilt of any of the Solar System 's planets ( about degree ) , and its orbital eccentricity is the largest of all known planets in the Solar System . At aphelion , Mercury is about 1.5 times as far from the Sun as it is at perihelion . Mercury 's surface appears heavily cratered and is similar in appearance to the Moon 's , indicating that it has been geologically inactive for billions of years . Having almost no atmosphere to retain heat , it has surface temperatures that vary diurnally more than on any other planet in the Solar System , ranging from 100 K at night to 700 K during the day across the equatorial regions . The polar regions are constantly below 180 K . The planet has no known natural satellites . Two spacecraft have visited Mercury : flew by in 1974 and 1975 ; and MESSENGER , launched in 2004 , orbited Mercury over 4,000 times in four years before exhausting its fuel and crashing into the planet 's surface on April 30 , 2015 . |
1991 | United_States | The United States is the leading nation in the world "with the highest amount of doubt about the conventional wisdom of climate change." | United States The United States of America ( USA ) , commonly known as the United States ( U.S. ) or America , is a constitutional federal republic composed of 50 states , a federal district , five major self-governing territories , and various possessions . Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico . The state of Alaska is in the northwest corner of North America , bordered by Canada to the east and across the Bering Strait from Russia to the west . The state of Hawaii is an archipelago in the mid-Pacific Ocean . The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea . Nine time zones are covered . The geography , climate and wildlife of the country are extremely diverse . At 3.8 million square miles ( 9.8 million km2 ) and with over 324 million people , the United States is the world 's third - or fourth-largest country by total area , third-largest by land area , and the third-most populous . It is one of the world 's most ethnically diverse and multicultural nations , and is home to the world 's largest immigrant population . The capital is Washington , D.C. , and the largest city is New York City ; nine other major metropolitan areas -- each with at least 4.5 million inhabitants and the largest having more than 13 million people -- are Los Angeles , Chicago , Dallas , Houston , Philadelphia , Miami , Atlanta , Boston , and San Francisco . Paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago . European colonization began in the 16th century . The United States emerged from 13 British colonies along the East Coast . Numerous disputes between Great Britain and the colonies following the Seven Years ' War led to the American Revolution , which began in 1775 . On July 4 , 1776 , during the course of the American Revolutionary War , the colonies unanimously adopted the Declaration of Independence . The war ended in 1783 with recognition of the independence of the United States by Great Britain , representing the first successful war of independence against a European power . The current constitution was adopted in 1788 , after the Articles of Confederation , adopted in 1781 , were felt to have provided inadequate federal powers . The first ten amendments , collectively named the Bill of Rights , were ratified in 1791 and designed to guarantee many fundamental civil liberties . The United States embarked on a vigorous expansion across North America throughout the 19th century , displacing Native American tribes , acquiring new territories , and gradually admitting new states until it spanned the continent by 1848 . During the second half of the 19th century , the American Civil War led to the end of legal slavery in the country . By the end of that century , the United States extended into the Pacific Ocean , and its economy , driven in large part by the Industrial Revolution , began to soar . The Spanish -- American War and confirmed the country 's status as a global military power . The United States emerged from as a global superpower , the first country to develop nuclear weapons , the only country to use them in warfare , and a permanent member of the United Nations Security Council . The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the world 's sole superpower . The U.S. is a founding member of the United Nations , World Bank , International Monetary Fund , Organization of American States ( OAS ) , and other international organizations . The United States is a highly developed country , with the world 's largest economy by nominal GDP and second-largest economy by PPP . Though its population is only 4.3 % of the world total , Americans hold nearly 40 % of the total wealth in the world . The United States ranks among the highest in several measures of socioeconomic performance , including average wage , human development , per capita GDP , and productivity per person . While the U.S. economy is considered post-industrial , characterized by the dominance of services and knowledge economy , the manufacturing sector remains the second-largest in the world . Accounting for approximately a quarter of global GDP and a third of global military spending , the United States is the world 's foremost economic and military power . The United States is a prominent political and cultural force internationally , and a leader in scientific research and technological innovations . |
559 | Deforestation_and_climate_change | And there is a lot of evidence that climate change is diminishing biodiversity, which can be seen in these alpine meadows as well. | Deforestation and climate change Deforestation is one of the main contributors to climate change . It is the second largest anthropogenic source of carbon dioxide to the atmosphere , after fossil fuel combustion . Deforestation and forest degradation contribute to atmospheric greenhouse gas emissions through combustion of forest biomass and decomposition of remaining plant material and soil carbon . It used to account for more than 20 % of carbon dioxide emissions , but it 's currently somewhere around the 10 % mark . By 2008 , deforestation was 12 % of total , or 15 % if peatlands are included . These proportions are likely to have fallen since given the continued rise of fossil fuel use . Averaged over all land and ocean surfaces , temperatures warmed roughly 1.53 ° F ( 0.85 ° C ) between 1880 and 2012 , according to the Intergovernmental Panel on Climate Change . In the Northern Hemisphere , 1983 to 2012 were the warmest 30-year period of the last 1400 years . |
2924 | Global_warming_controversy | The long-term correlation between CO2 and temperature is well established. | Global warming controversy The global warming controversy concerns the public debate over whether global warming is occurring , how much has occurred in modern times , what has caused it , what its effects will be , whether any action should be taken to curb it , and if so what that action should be . In the scientific literature , there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases . No scientific body of national or international standing disagrees with this view , though a few organizations with members in extractive industries hold non-committal positions . Disputes over the key scientific facts of global warming are more prevalent in the media than in the scientific literature , where such issues are treated as resolved , and such disputes are more prevalent in the United States than globally . Political and popular debate concerning the existence and cause of climate change includes the reasons for the increase seen in the instrumental temperature record , whether the warming trend exceeds normal climatic variations , and whether human activities have contributed significantly to it . Scientists have resolved these questions decisively in favour of the view that the current warming trend exists and is ongoing , that human activity is the cause , and that it is without precedent in at least 2000 years . Public disputes that also reflect scientific debate include estimates of how responsive the climate system might be to any given level of greenhouse gases ( climate sensitivity ) , how global climate change will play out at local and regional scales , and what the consequences of global warming will be . Global warming remains an issue of widespread political debate , often split along party political lines , especially in the United States . Many of the issues that are settled within the scientific community , such as human responsibility for global warming , remain the subject of politically or economically motivated attempts to downplay , dismiss or deny them -- an ideological phenomenon categorised by academics and scientists as climate change denial . The sources of funding for those involved with climate science -- both supporting and opposing mainstream scientific positions -- have been questioned by both sides . There are debates about the best policy responses to the science , their cost-effectiveness and their urgency . Climate scientists , especially in the United States , have reported official and oil-industry pressure to censor or suppress their work and hide scientific data , with directives not to discuss the subject in public communications . Legal cases regarding global warming , its effects , and measures to reduce it have reached American courts . The fossil fuels lobby has been identified as overtly or covertly supporting efforts to undermine or discredit the scientific consensus on global warming . |
1775 | Venus | Venus very likely underwent a runaway or 'moist' greenhouse phase earlier in its history, and today is kept hot by a dense CO2 atmosphere. | Venus Venus is the second planet from the Sun , orbiting it every 224.7 Earth days . It has the longest rotation period ( 243 days ) of any planet in the Solar System and rotates in the opposite direction to most other planets . It has no natural satellites . It is named after the Roman goddess of love and beauty . It is the second-brightest natural object in the night sky after the Moon , reaching an apparent magnitude of − 4.6 , bright enough to cast shadows at night and , though rare , occasionally be visible in broad daylight . Because Venus orbits within Earth 's orbit it is an inferior planet and never appears to venture far from the Sun ; its maximum angular distance from the Sun ( elongation ) is 47.8 ° . Venus is a terrestrial planet and is sometimes called Earth 's `` sister planet '' because of their similar size , mass , proximity to the Sun , and bulk composition . It is radically different from Earth in other respects . It has the densest atmosphere of the four terrestrial planets , consisting of more than 96 % carbon dioxide . The atmospheric pressure at the planet 's surface is 92 times that of Earth , or roughly the pressure found 900 m underwater on Earth . Venus is by far the hottest planet in the Solar System , with a mean surface temperature of 735 K , even though Mercury is closer to the Sun . Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid , preventing its surface from being seen from space in visible light . It may have had water oceans in the past , but these would have vaporized as the temperature rose due to a runaway greenhouse effect . The water has probably photodissociated , and the free hydrogen has been swept into interplanetary space by the solar wind because of the lack of a planetary magnetic field . Venus 's surface is a dry desertscape interspersed with slab-like rocks and is periodically resurfaced by volcanism . As one of the brightest objects in the sky , Venus has been a major fixture in human culture for as long as records have existed . It has been made sacred to gods of many cultures , and has been a prime inspiration for writers and poets as the `` morning star '' and `` evening star '' . Venus was the first planet to have its motions plotted across the sky , as early as the second millennium BC . As the closest planet to Earth , Venus has been a prime target for early interplanetary exploration . It was the first planet beyond Earth visited by a spacecraft ( Mariner 2 in 1962 ) , and the first to be successfully landed on ( by Venera 7 in 1970 ) . Venus 's thick clouds render observation of its surface impossible in visible light , and the first detailed maps did not emerge until the arrival of the Magellan orbiter in 1991 . Plans have been proposed for rovers or more complex missions , but they are hindered by Venus 's hostile surface conditions . |
2455 | Ice_age | When CO2 levels were higher in the past, solar levels were also lower. | Ice age An ice age is a period of long-term reduction in the temperature of Earth 's surface and atmosphere , resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers . Within a long-term ice age , individual pulses of cold climate are termed `` glacial periods '' ( or alternatively `` glacials '' or `` glaciations '' or colloquially as `` ice age '' ) , and intermittent warm periods are called `` interglacials '' . In the terminology of glaciology , ice age implies the presence of extensive ice sheets in both northern and southern hemispheres . By this definition , we are in an interglacial period -- the Holocene -- of the ice age . The ice age began 2.6 million years ago at the start of the Pleistocene epoch , because the Greenland , Arctic , and Antarctic ice sheets still exist . |
2692 | Climate_system | Volcanoes, solar variations, clouds, methane, aerosols - these all change the way energy enters and/or leaves our climate. | Climate system Earth's climate arises from the interaction of five major climate system components: the atmosphere (air), the hydrosphere (water), the cryosphere (ice and permafrost), the lithosphere (earth's upper rocky layer) and the biosphere (living things). Climate is the average weather, typically over a period of 30 years, and is determined by a combination of processes in the climate system, such as ocean currents and wind patterns. Circulation in the atmosphere and oceans is primarily driven by solar radiation and transports heat from the tropical regions to regions that receive less energy from the Sun. The water cycle also moves energy throughout the climate system. In addition, different chemical elements, necessary for life, are constantly recycled between the different components. The climate system can change due to internal variability and external forcings. These external forcings can be natural, such as variations in solar intensity and volcanic eruptions, or caused by humans. Accumulation of heat-trapping greenhouse gases, mainly being emitted by people burning fossil fuels, is causing global warming. Human activity also releases cooling aerosols, but their net effect is far less than that of greenhouse gases. Changes can be amplified by feedback processes in the different climate system components. |
1689 | Evidence-based_medicine | Evidence is building that net cloud feedback is likely positive and unlikely to be strongly negative. | Evidence-based medicine Evidence-based medicine ( EBM ) is an approach to medical practice intended to optimize decision-making by emphasizing the use of evidence from well-designed and well-conducted research . Although all medicine based on science has some degree of empirical support , EBM goes further , classifying evidence by its epistemologic strength and requiring that only the strongest types ( coming from meta-analyses , systematic reviews , and randomized controlled trials ) can yield strong recommendations ; weaker types ( such as from case-control studies ) can yield only weak recommendations . The term was originally used to describe an approach to teaching the practice of medicine and improving decisions by individual physicians about individual patients . Use of the term rapidly expanded to include a previously described approach that emphasized the use of evidence in the design of guidelines and policies that apply to groups of patients and populations ( `` evidence-based practice policies '' ) . It has subsequently spread to describe an approach to decision-making that is used at virtually every level of health care as well as other fields ( evidence-based practice ) . Whether applied to medical education , decisions about individuals , guidelines and policies applied to populations , or administration of health services in general , evidence-based medicine advocates that to the greatest extent possible , decisions and policies should be based on evidence , not just the beliefs of practitioners , experts , or administrators . It thus tries to assure that a clinician 's opinion , which may be limited by knowledge gaps or biases , is supplemented with all available knowledge from the scientific literature so that best practice can be determined and applied . It promotes the use of formal , explicit methods to analyze evidence and makes it available to decision makers . It promotes programs to teach the methods to medical students , practitioners , and policy makers . |
1771 | Scientific_consensus_on_climate_change | Peer-reviewed research, physics, and math all tell us that a grand solar minimum would have no more than a 0.3°C cooling effect, barely enough to put a dent in human-caused global warming. | Scientific consensus on climate change There is currently a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports. Nearly all actively publishing climate scientists (97–98%) support the consensus on anthropogenic climate change, and the remaining 2% of contrarian studies either cannot be replicated or contain errors. |
2520 | Second_law_of_thermodynamics | According to the second law of thermodynamics such a planetary machine can never exist." | Second law of thermodynamics The second law of thermodynamics states that the total entropy of an isolated system can only increase over time . It can remain constant in ideal cases where the system is in a steady state ( equilibrium ) or undergoing a reversible process . The increase in entropy accounts for the irreversibility of natural processes , and the asymmetry between future and past . Historically , the second law was an empirical finding that was accepted as an axiom of thermodynamic theory . Statistical thermodynamics , classical or quantum , explains the microscopic origin of the law . The second law has been expressed in many ways . Its first formulation is credited to the French scientist Sadi Carnot in 1824 , who showed that there is an upper limit to the efficiency of conversion of heat to work in a heat engine . |
132 | Climate_change_adaptation | Climate change is not making natural disasters worse | Climate change adaptation Climate change adaptation is a response to global warming and climate change , that seeks to reduce the vulnerability of social and biological systems to relatively sudden change and thus offset the effects of global warming . Even if emissions are stabilized relatively soon , global warming and its effects will last many years , and adaptation will be necessary to the resulting changes in climate . Adaptation is especially important in developing countries since those countries are predicted to bear the brunt of the effects of global warming . That is , the capacity and potential for humans to adapt ( called adaptive capacity ) is unevenly distributed across different regions and populations , and developing countries generally have less capacity to adapt ( Schneider et al. , 2007 ) . Furthermore , the degree of adaptation correlates to the situational focus on environmental issues . Therefore , adaptation requires the situational assessment of sensitivity and vulnerability to environmental impacts . Adaptive capacity is closely linked to social and economic development ( IPCC , 2007 ) . The economic costs of adaptation to climate change are likely to cost billions of dollars annually for the next several decades , though the amount of money needed is unknown . Donor countries promised an annual $ 100 billion by 2020 through the Green Climate Fund for developing countries to adapt to climate change . However , while the fund was set up during COP16 in Cancún , concrete pledges by developed countries have not been forthcoming . The adaptation challenge grows with the magnitude and the rate of climate change . Another response to climate change , known as climate change mitigation ( Verbruggen , 2007 ) is to reduce greenhouse gas ( GHG ) emissions and/or enhance the removal of these gases from the atmosphere ( through carbon sinks ) . Even the most effective reductions in emissions , however , would not prevent further climate change impacts , making the need for adaptation unavoidable ( Klein et al. , 2007 ) . In a literature assessment , Klein et al. ( 2007 ) assessed options for adaptation . They concluded , with very high confidence , that in the absence of mitigation efforts , the effects of climate change would reach such a magnitude as to make adaptation impossible for some natural ecosystems . Others are concerned that climate adaptation programs might interfere with the existing development programs and thus lead to unintended consequences for vulnerable groups . For human systems , the economic and social costs of unmitigated climate change would be very high . |
207 | Climate_of_Mars | Each of the six major past ice ages began when the atmospheric carbon dioxide content was far higher than at present. | Climate of Mars The climate of Mars has been an issue of scientific curiosity for centuries , in part because Mars is the only terrestrial planet whose surface can be directly observed in detail from the Earth with help from a telescope . Although Mars is smaller than the Earth , at 11 % of Earth 's mass , and 50 % farther from the Sun than the Earth , its climate has important similarities , such as the polar ice caps , seasonal changes and the observable presence of weather patterns . It has attracted sustained study from planetologists and climatologists . While Mars 's climate has similarities to Earth 's , including periodic ice ages , there are also important differences , such as much lower thermal inertia . Mars ' atmosphere has a scale height of approximately 11 km , 60 % greater than that on Earth . The climate is of considerable relevance to the question of whether life is or was present on the planet . The climate briefly received more interest in the news due to NASA measurements indicating increased sublimation of the south polar icecap leading to some popular press speculation that Mars was undergoing a parallel bout of global warming , although Mars ' average temperature has actually cooled in recent decades . Mars has been studied by Earth-based instruments since the 17th century but it is only since the exploration of Mars began in the mid-1960s that close-range observation has been possible . Flyby and orbital spacecraft have provided data from above , while direct measurements of atmospheric conditions have been provided by a number of landers and rovers . Advanced Earth orbital instruments today continue to provide some useful `` big picture '' observations of relatively large weather phenomena . The first Martian flyby mission was Mariner 4 which arrived in 1965 . That quick two-day pass ( July 14 -- 15 , 1965 ) was limited and crude in terms of its contribution to the state of knowledge of Martian climate . Later Mariner missions ( Mariner 6 , and Mariner 7 ) filled in some of the gaps in basic climate information . Data-based climate studies started in earnest with the Viking program in 1975 and continues with such probes as the Mars Reconnaissance Orbiter . This observational work has been complemented by a type of scientific computer simulation called the Mars general circulation model . Several different iterations of MGCM have led to an increased understanding of Mars as well as the limits of such models . |
2067 | North_Pole | Arctic, Antarctic and Greenland ice loss is accelerating due to global warming. | North Pole The North Pole , also known as the Geographic North Pole or Terrestrial North Pole , is ( subject to the caveats explained below ) defined as the point in the Northern Hemisphere where the Earth 's axis of rotation meets its surface . The North Pole is the northernmost point on the Earth , lying diametrically opposite the South Pole . It defines geodetic latitude 90 ° North , as well as the direction of true north . At the North Pole all directions point south ; all lines of longitude converge there , so its longitude can be defined as any degree value . Along tight latitude circles , counterclockwise is east and clockwise is west . The North Pole is at the center of the Northern Hemisphere . While the South Pole lies on a continental land mass , the North Pole is located in the middle of the Arctic Ocean amid waters that are almost permanently covered with constantly shifting sea ice . This makes it impractical to construct a permanent station at the North Pole ( unlike the South Pole ) . However , the Soviet Union , and later Russia , constructed a number of manned drifting stations on a generally annual basis since 1937 , some of which have passed over or very close to the Pole . Since 2002 , the Russians have also annually established a base , Barneo , close to the Pole . This operates for a few weeks during early spring . Studies in the 2000s predicted that the North Pole may become seasonally ice-free because of Arctic ice shrinkage , with timescales varying from 2016 to the late 21st century or later . The sea depth at the North Pole has been measured at 4261 m by the Russian Mir submersible in 2007 and at 4,087 m ( 13,410 ft ) by USS Nautilus in 1958 . The nearest land is usually said to be Kaffeklubben Island , off the northern coast of Greenland about 700 km away , though some perhaps non-permanent gravel banks lie slightly closer . The nearest permanently inhabited place is Alert in the Qikiqtaaluk Region , Nunavut , Canada , which is located 817 km from the Pole . |
3024 | Positive_feedback | Unlike the simple example of positive feedback we learned in high school, the increase from every round of feedback gets smaller and smaller, in the case of the enhanced greenhouse effect. | Positive feedback Positive feedback is a process that occurs in a feedback loop in which the effects of a small disturbance on a system include an increase in the magnitude of the perturbation . That is , A produces more of B which in turn produces more of A . In contrast , a system in which the results of a change act to reduce or counteract it has negative feedback . Both concepts play an important role in science and engineering , including biology , chemistry , and cybernetics . Mathematically , positive feedback is defined as a positive loop gain around a closed loop of cause and effect . That is , positive feedback is in phase with the input , in the sense that it adds to make the input larger . Positive feedback tends to cause system instability . When the loop gain is positive and above 1 , there will typically be exponential growth , increasing oscillations , chaotic behavior or other divergences from equilibrium . System parameters will typically accelerate towards extreme values , which may damage or destroy the system , or may end with the system latched into a new stable state . Positive feedback may be controlled by signals in the system being filtered , damped , or limited , or it can be cancelled or reduced by adding negative feedback . Positive feedback is used in digital electronics to force voltages away from intermediate voltages into ' 0 ' and ' 1 ' states . On the other hand , thermal runaway is a positive feedback that can destroy semiconductor junctions . Positive feedback in chemical reactions can increase the rate of reactions , and in some cases can lead to explosions . Positive feedback in mechanical design causes tipping-point , or ` over-centre ' , mechanisms to snap into position , for example in switches and locking pliers . Out of control , it can cause bridges to collapse . Positive feedback in economic systems can cause boom-then-bust cycles . A familiar example of positive feedback is the loud squealing or howling sound produced by audio feedback in public address systems : the microphone picks up sound from its own loudspeakers , amplifies it , and sends it through the speakers again . |
997 | Scientific_consensus_on_climate_change | Ever since 2012, scientists have been debating a complex and frankly explosive idea about how a warming planet will alter our weather — one that, if it's correct, would have profound implications across the Northern Hemisphere and especially in its middle latitudes | Scientific consensus on climate change There is currently a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports. Nearly all actively publishing climate scientists (97–98%) support the consensus on anthropogenic climate change, and the remaining 2% of contrarian studies either cannot be replicated or contain errors. |
2500 | Climate_change_denial | Believers think the warming is man-made, while the skeptics believe the warming is natural and contributions from man are minimal and certainly not potentially catastrophic à la Al Gore.' | Climate change denial Climate change denial , or global warming denial , is part of the global warming controversy . It involves denial , dismissal , unwarranted doubt or contrarian views which strongly depart from the scientific opinion on climate change , including the extent to which it is caused by humans , its impacts on nature and human society , or the potential of adaptation to global warming by human actions . Some deniers do endorse the term , but others often prefer the term climate change skepticism , although this is a misnomer for those who deny anthropogenic global warming . In effect , the two terms form a continuous , overlapping range of views , and generally have the same characteristics : both reject , to a greater or lesser extent , mainstream scientific opinion on climate change . Climate change denial can also be implicit , when individuals or social groups accept the science but fail to come to terms with it or to translate their acceptance into action . Several social science studies have analyzed these positions as forms of denialism . Campaigning to undermine public trust in climate science has been described as a `` denial machine '' of industrial , political and ideological interests , supported by conservative media and skeptical bloggers in manufacturing uncertainty about global warming . In the public debate , phrases such as climate skepticism have frequently been used with the same meaning as climate denialism . The labels are contested : those actively challenging climate science commonly describe themselves as `` skeptics '' , but many do not comply with common standards of scientific skepticism and , regardless of evidence , persistently deny the validity of human caused global warming . Although scientific opinion on climate change is that human activity is extremely likely to be the primary driver of climate change , the politics of global warming have been affected by climate change denial , hindering efforts to prevent climate change and adapt to the warming climate . Those promoting denial commonly use rhetorical tactics to give the appearance of a scientific controversy where there is none . Of the world 's countries , the climate change denial industry is most powerful in the United States . Since January 2015 , the United States Senate Committee on Environment and Public Works has been chaired by oil lobbyist and climate change denier Jim Inhofe . Inhofe is notorious for having called climate change `` the greatest hoax ever perpetrated against the American people '' and for having claimed to have debunked the alleged hoax in February 2015 when he brought a snowball with him in the Senate chamber and tossed it across the floor . Organised campaigning to undermine public trust in climate science is associated with conservative economic policies and backed by industrial interests opposed to the regulation of emissions . Climate change denial has been associated with the fossil fuels lobby , the Koch brothers , industry advocates and libertarian think tanks , often in the United States . More than 90 % of papers sceptical on climate change originate from right-wing think tanks . The total annual income of these climate change counter-movement-organizations is roughly $ 900 million . Between 2002 and 2010 , nearly $ 120 million ( # 77 million ) was anonymously donated via the Donors Trust and Donors Capital Fund to more than 100 organisations seeking to undermine the public perception of the science on climate change . In 2013 the Center for Media and Democracy reported that the State Policy Network ( SPN ) , an umbrella group of 64 U.S. think tanks , had been lobbying on behalf of major corporations and conservative donors to oppose climate change regulation . Since the late 1970s , oil companies have published research broadly in line with the standard views on global warming . Despite this , oil companies organized a climate change denial campaign to disseminate public disinformation for several decades , a strategy that has been compared to the organized denial of the hazards of tobacco smoking by tobacco companies . |
538 | Climate_change_in_the_Arctic | Previous studies have shown that weakening carbon sinks will add 0.25°C, forest dieback will add 0.11°C, permafrost thaw will add 0.9°C and increased bacterial respiration will add 0.02°C. | Climate change in the Arctic The effects of global warming in the Arctic , or climate change in the Arctic include rising temperatures , loss of sea ice , and melting of the Greenland ice sheet with a related cold temperature anomaly , observed in recent years . Potential methane release from the region , especially through the thawing of permafrost and methane clathrates , is also a concern . The Arctic warms twice as fast compared to the rest of the world . The pronounced warming signal , the amplified response of the Arctic to global warming , it is often seen as a leading indicator of global warming . The melting of Greenland 's ice sheet is linked to polar amplification . According to a study published in 2016 , about 0.5 ◦ C of the warming in the Arctic has been attributed to reductions in sulfate aerosols in Europe since 1980 . |
2967 | Waste_heat | The contribution of waste heat to the global climate is 0.028 W/m2. | Waste heat Waste heat is by necessity produced both by machines that do work and in other processes that use energy , for example in a refrigerator warming the room air or a combustion engine releasing heat into the environment . The need for many systems to reject heat as a by-product of their operation is fundamental to the laws of thermodynamics . Waste heat has lower utility ( or in thermodynamics lexicon a lower exergy or higher entropy ) than the original energy source . Sources of waste heat include all manner of human activities , natural systems , and all organisms . Instead of being `` wasted '' by release into the ambient environment , sometimes waste heat ( or cold ) can be utilized by another process ( such as using hot engine coolant to heat a vehicle ) , or a portion of heat that would otherwise be wasted can be reused in the same process if make-up heat is added to the system ( as with heat recovery ventilation in a building ) . Thermal energy storage , which includes technologies both for short - and long-term retention of heat or cold , can create or improve the utility of waste heat ( or cold ) . One example is waste heat from air conditioning machinery stored in a buffer tank to aid in night time heating . Another is seasonal thermal energy storage ( STES ) at a foundry in Sweden . The heat is stored in the bedrock surrounding a cluster of heat exchanger equipped boreholes , and is used for space heating in an adjacent factory as needed , even months later . An example of using STES to utilize natural waste heat is the Drake Landing Solar Community in Alberta , Canada , which , by using a cluster of boreholes in bedrock for interseasonal heat storage , obtains 97 percent of its year-round heat from solar thermal collectors on the garage roofs . Another STES application is storing winter cold underground , for summer air conditioning . On a biological scale , all organisms reject waste heat as part of their metabolic processes , and will die if the ambient temperature is too high to allow this . Anthropogenic waste heat is thought by some to contribute to the urban heat island effect . The biggest point sources of waste heat originate from machines ( such as electrical generators or industrial processes , such as steel or glass production ) and heat loss through building envelopes . The burning of transport fuels is a major contribution to waste heat . |
814 | Climate | Global Ocean Circulation Appears To Be Collapsing Due To A Warming Planet | Climate Climate is the statistics of weather , usually over a 30-year interval . It is measured by assessing the patterns of variation in temperature , humidity , atmospheric pressure , wind , precipitation , atmospheric particle count and other meteorological variables in a given region over long periods of time . Climate differs from weather , in that weather only describes the short-term conditions of these variables in a given region . A region 's climate is generated by the climate system , which has five components : atmosphere , hydrosphere , cryosphere , lithosphere , and biosphere . The climate of a location is affected by its latitude , terrain , and altitude , as well as nearby water bodies and their currents . Climates can be classified according to the average and the typical ranges of different variables , most commonly temperature and precipitation . The most commonly used classification scheme was the Köppen climate classification . The Thornthwaite system , in use since 1948 , incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it . The Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region . Paleoclimatology is the study of ancient climates . Since direct observations of climate are not available before the 19th century , paleoclimates are inferred from proxy variables that include non-biotic evidence such as sediments found in lake beds and ice cores , and biotic evidence such as tree rings and coral . Climate models are mathematical models of past , present and future climates . Climate change may occur over long and short timescales from a variety of factors ; recent warming is discussed in global warming . Global warming results in redistributions . For example , `` a 3 ° C change in mean annual temperature corresponds to a shift in isotherms of approximately 300 -- 400 km in latitude ( in the temperate zone ) or 500 m in elevation . Therefore , species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones '' . |
1286 | Arctic_methane_emissions | Arctic greening was recently cited, in a major report by the U.S. Geological Survey, as the central reason that the state of Alaska, despite worsening wildfires and more thaw of permafrost, might still be able to stow away more carbon than it loses over the course of the 21st century." | Arctic methane emissions Arctic methane release is the release of methane from seas and soils in permafrost regions of the Arctic . While a long-term natural process , it is exacerbated by global warming . This results in a positive feedback effect , as methane is itself a powerful greenhouse gas . The Arctic region is one of the many natural sources of the greenhouse gas methane . Global warming accelerates its release , due to both release of methane from existing stores , and from methanogenesis in rotting biomass . Large quantities of methane are stored in the Arctic in natural gas deposits , permafrost , and as undersea clathrates . Permafrost and clathrates degrade on warming , thus large releases of methane from these sources may arise as a result of global warming . Other sources of methane include submarine taliks , river transport , ice complex retreat , submarine permafrost and decaying gas hydrate deposits . Concentrations in the Arctic atmosphere are higher by 8 -- 10 % than that in the Antarctic atmosphere . During cold glacier epochs , this gradient decreases to practically insignificant levels . Land ecosystems are considered the main sources of this asymmetry , although it has been suggested that `` the role of the Arctic Ocean is significantly underestimated . '' Soil temperature and moisture levels have been found to be significant variables in soil methane fluxes in tundra environments . |
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