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2132 | Julian_Assange | Freedom of Information (FOI) requests were ignored | Julian Assange Julian Paul Assange ( -LSB- əˈsɒnʒ -RSB- born Julian Paul Hawkins , 3 July 1971 ) is an Australian computer programmer and the founder of WikiLeaks , an organisation which he founded in 2006 . He has won accolades including the Sam Adams Award and Martha Gellhorn Prize for Journalism . Assange founded WikiLeaks in 2006 , but came to global prominence in 2010 , when WikiLeaks published a series of leaks provided by Chelsea Manning . These leaks included the Collateral Murder video ( April 2010 ) , the Afghanistan war logs ( July 2010 ) , the Iraq war logs ( October 2010 ) , and CableGate ( November 2010 ) . Following the 2010 leaks , the United States government launched a criminal investigation into WikiLeaks and asked allied nations for assistance . In November 2010 , a request was made for Assange 's extradition to Sweden , where he had been questioned months earlier over allegations of sexual assault and rape . Assange continued to deny the allegations , and expressed concern that he would be extradited from Sweden to the United States because of his perceived role in publishing secret American documents . Assange surrendered himself to UK police on 7 December 2010 , and was held for ten days in solitary confinement before being released on bail . He sought and was granted asylum by Ecuador in August 2012 . He has since remained in the Embassy of Ecuador in London , and is unable to leave without being arrested for breaching his bail conditions . On 19 May 2017 , the Swedish prosecutors dropped the investigation into rape accusations against Assange and applied to revoke his arrest warrant , although the Metropolitan Police have indicated that an arrest warrant is still in force for Assange 's failure to surrender himself to the British court . |
2620 | Climate_change_feedback | "...the largest of all the positive or temperature-amplifying feedbacks in the UN's arsenal is the water-vapor feedback. | Climate change feedback Climate change feedback is important in the understanding of global warming because feedback processes may amplify or diminish the effect of each climate forcing , and so play an important part in determining the climate sensitivity and future climate state . Feedback in general is the process in which changing one quantity changes a second quantity , and the change in the second quantity in turn changes the first . Positive feedback amplifies the change in the first quantity while negative feedback reduces it . The term `` forcing '' means a change which may `` push '' the climate system in the direction of warming or cooling . An example of a climate forcing is increased atmospheric concentrations of greenhouse gases . By definition , forcings are external to the climate system while feedbacks are internal ; in essence , feedbacks represent the internal processes of the system . Some feedbacks may act in relative isolation to the rest of the climate system ; others may be tightly coupled ; hence it may be difficult to tell just how much a particular process contributes . Forcings , feedbacks and the dynamics of the climate system determine how much and how fast the climate changes . The main positive feedback in global warming is the tendency of warming to increase the amount of water vapor in the atmosphere , which in turn leads to further warming . The main negative feedback comes from the Stefan -- Boltzmann law , the amount of heat radiated from the Earth into space changes with the fourth power of the temperature of Earth 's surface and atmosphere . Some observed and potential effects of global warming are positive feedbacks , which contribute directly to further global warming . The Intergovernmental Panel on Climate Change 's ( IPCC ) Fourth Assessment Report states that `` Anthropogenic warming could lead to some effects that are abrupt or irreversible , depending upon the rate and magnitude of the climate change . '' |
1374 | Global_warming | world temperatures, because they have gone up only very slowly, less than half as fast as the scientific consensus predicted in 1990 | 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 . |
2951 | Lucas_pseudoprime | The two most cited composites are PMOD and ACRIM. | Lucas pseudoprime Lucas pseudoprimes and Fibonacci pseudoprimes are composite integers that pass certain tests which all primes and very few composite numbers pass : in this case , criteria relative to some Lucas sequence . |
302 | Greenhouse_gas | In addition, [climate models] ignore the fact that enriching the atmosphere with CO2 is beneficial | 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 . |
1562 | Greenhouse_gas | Methane is the only cause of climate change. | 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 . |
282 | Intergovernmental_Panel_on_Climate_Change | The panel was forced to retract a statement in its 2007 report saying all Himalayan glaciers could melt entirely by 2035. | Intergovernmental Panel on Climate Change The Intergovernmental Panel on Climate Change ( IPCC ) is a scientific and intergovernmental body under the auspices of the United Nations , set up at the request of member governments , dedicated to the task of providing the world with an objective , scientific view of climate change and its political and economic impacts . It was first established in 1988 by two United Nations organizations , the World Meteorological Organization ( WMO ) and the United Nations Environment Programme ( UNEP ) , and later endorsed by the United Nations General Assembly through Resolution 43/53 . Membership of the IPCC is open to all members of the WMO and UNEP . The IPCC produces reports that support the United Nations Framework Convention on Climate Change ( UNFCCC ) , which is the main international treaty on climate change . The ultimate objective of the UNFCCC is to `` stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic -LSB- i.e. , human-induced -RSB- interference with the climate system '' . IPCC reports cover `` the scientific , technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change , its potential impacts and options for adaptation and mitigation . '' The IPCC does not carry out its own original research , nor does it do the work of monitoring climate or related phenomena itself . The IPCC bases its assessment on the published literature , which includes peer-reviewed and non-peer-reviewed sources . Thousands of scientists and other experts contribute ( on a voluntary basis , without payment from the IPCC ) to writing and reviewing reports , which are then reviewed by governments . IPCC reports contain a `` Summary for Policymakers '' , which is subject to line-by-line approval by delegates from all participating governments . Typically this involves the governments of more than 120 countries . The IPCC provides an internationally accepted authority on climate change , producing reports which have the agreement of leading climate scientists and the consensus of participating governments . The 2007 Nobel Peace Prize was shared , in equal parts , between the IPCC and Al Gore . |
1115 | Solar_particle_event | This "blocking" effect means extreme events can unfold." | Solar particle event A solar proton event ( SPE ) , or `` proton storm '' , occurs when particles ( mostly protons ) emitted by the Sun become accelerated either close to the Sun during a flare or in interplanetary space by CME shocks . The events can include other nuclei such as helium ions and HZE ions . These particles cause multiple effects . They can penetrate the Earth 's magnetic field and cause ionization in the ionosphere . The effect is similar to auroral events , except that protons rather than electrons are involved . Energetic protons are a significant radiation hazard to spacecraft and astronauts . |
148 | Cloud_feedback | Previous IPCC reports tended to assume that clouds would have a neutral impact because the warming and cooling feedbacks would cancel each other out. | Cloud feedback Cloud feedback is the coupling between cloudiness and surface air temperature where a surface air temperature change leads to a change in clouds , which could then amplify or diminish the initial temperature perturbation . Cloud feedbacks can affect the magnitude of internally generated climate variability or they can affect the magnitude of climate change resulting from external radiative forcings . Global warming is expected to change the distribution and type of clouds . Seen from below , clouds emit infrared radiation back to the surface , and so exert a warming effect ; seen from above , clouds reflect sunlight and emit infrared radiation to space , and so exert a cooling effect . Cloud representations vary among global climate models , and small changes in cloud cover have a large impact on the climate . Differences in planetary boundary layer cloud modeling schemes can lead to large differences in derived values of climate sensitivity . A model that decreases boundary layer clouds in response to global warming has a climate sensitivity twice that of a model that does not include this feedback . However , satellite data show that cloud optical thickness actually increases with increasing temperature . Whether the net effect is warming or cooling depends on details such as the type and altitude of the cloud ; details that are difficult to represent in climate models . |
3032 | Carbon_dioxide | Consequently, CO2 levels at around 1,000 to 2,300 ppm were actually low enough to promote glaciation in the southern continent of Gondwana. | 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 . |
1577 | Project_Steve | Over 31,000 scientists signed the OISM Petition Project. | Project Steve Project Steve is a list of scientists with the given name Stephen/Steven or a variation thereof ( e.g. , Stephanie , Stefan , Esteban , etc. ) who `` support evolution '' . It was originally created by the National Center for Science Education as a `` tongue-in-cheek parody '' of creationist attempts to collect a list of scientists who `` doubt evolution , '' such as the Answers in Genesis ' list of scientists who accept the biblical account of the Genesis creation narrative or the Discovery Institute 's A Scientific Dissent From Darwinism . The list pokes fun at such endeavors to make it clear that , `` We did not wish to mislead the public into thinking that scientific issues are decided by who has the longer list of scientists ! '' It also honors Stephen Jay Gould . However , at the same time the project is a genuine collection of scientists . Despite the list 's restriction to only scientists with names like `` Steve '' , which in the United States limits the list to roughly 1 percent of the total population , Project Steve is longer and contains many more eminent scientists than any creationist list . In particular , Project Steve contains many more biologists than the creationist lists , with about 51 % of the listed Steves being biologists . The `` List of Steves '' webpage provides an updated total of scientist `` Steves '' who have signed the list . , Project Steve has 1,416 signatories . |
363 | Humid_subtropical_climate | Monsoons in China fail, the great rivers of Asia virtually dry up, and rainfall in central America falls by half. | Humid subtropical climate A humid subtropical climate is a zone of climate characterised by hot and humid summers where tropical air masses dominate , and mild winters . These climates normally lie on the southeast side of all continents , generally between latitudes 25 ° and 40 ° and are adjacent to tropical climates to the south . While many subtropical climates tend to be located at coastal or near coastal locations . in some cases they extend inland , most notably in southern China and the southern United States . Under the Köppen climate classification , Cfa and Cwa climates are described as mild temperate climates . This climate features mean temperatures in the coldest month between 0 ° C and 18 ° C and mean temperatures in the warmest month 22 ° C or higher . The Trewartha system was a 1966 update of the Köppen climate classification , and sought to redefine middle latitude climates into smaller zones ( the original Köppen system grouped all middle latitude climates into a single zone ) . Under the Trewartha climate classification , climates are termed humid subtropical when they have monthly mean air temperatures higher than 10 ° C ( 50 ° F ) for eight or more months a year and at least one month with mean temperature below 18 ° C ( 64.4 ° F ) . Normally , humid subtropical climates occupy the southernmost portions of the temperate zone from 23.5 to 35.0 north and south latitude . Rainfall often shows a summer peak , especially where monsoons are well developed , as in Southeast Asia and Florida ( USA ) . Other areas have a more uniform or varying rainfall cycles . Most summer rainfall occurs during thunderstorms that build up due to the intense surface heating and strong subtropical sun angle . Weak tropical lows that move in from adjacent warm tropical oceans , as well as infrequent tropical storms often contribute to high sun ( summer ) seasonal rainfall peaks . Winter rainfall is often associated with large storms in the westerlies that have fronts that reach down into subtropical latitudes . However , many subtropical climates such as southeast Asia or Florida have very dry winters , with frequent brush fires and water shortages . |
1331 | Petroleum | 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 | Petroleum Petroleum ( from petra #Greek : `` rock '' + oleum #Latin : `` oil '' . ) is a naturally occurring , yellow-to-black liquid found in geological formations beneath the Earth 's surface , which is commonly refined into various types of fuels . Components of petroleum are separated using a technique called fractional distillation . It consists of hydrocarbons of various molecular weights and other organic compounds . The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil . A fossil fuel , petroleum is formed when large quantities of dead organisms , usually zooplankton and algae , are buried underneath sedimentary rock and subjected to both intense heat and pressure . Petroleum has mostly been recovered by oil drilling ( natural petroleum springs are rare ) . Drilling is carried out after studies of structural geology ( at the reservoir scale ) , sedimentary basin analysis , and reservoir characterization ( mainly in terms of the porosity and permeability of geologic reservoir structures ) have been completed . It is refined and separated , most easily by distillation , into a large number of consumer products , from gasoline ( petrol ) and kerosene to asphalt and chemical reagents used to make plastics and pharmaceuticals . Petroleum is used in manufacturing a wide variety of materials , and it is estimated that the world consumes about 95 million barrels each day . Concern over the depletion of the earth 's finite reserves of oil , and the effect this would have on a society dependent on it , is a concept known as peak oil . The use of fossil fuels , such as petroleum , will have a negative impact on Earth 's biosphere , damaging ecosystems through events such as oil spills and releasing a range of pollutants into the air including ground-level ozone and sulfur dioxide from sulfur impurities in fossil fuels . The burning of fossil fuels plays the major role in the current episode of global warming . |
1143 | Global_warming_controversy | Skeptics have long pointed to ice gain in the Southern Hemisphere as evidence climate change wasn't occurring, but scientists warned that it was caused by natural variations and circulations in the atmosphere. | 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 . |
717 | Scientific_consensus_on_climate_change | Scientists used to think that ice sheets could take millennia to respond to changing climates | 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. |
2122 | Sea_surface_temperature | Dropped stations introduce warming bias | Sea surface temperature Sea surface temperature ( SST ) is the water temperature close to the ocean 's surface . The exact meaning of surface varies according to the measurement method used , but it is between 1 mm and 20 m below the sea surface . Air masses in the Earth 's atmosphere are highly modified by sea surface temperatures within a short distance of the shore . Localized areas of heavy snow can form in bands downwind of warm water bodies within an otherwise cold air mass . Warm sea surface temperatures are known to be a cause of tropical cyclogenesis over the Earth 's oceans . Tropical cyclones can also cause a cool wake , due to turbulent mixing of the upper 30 m of the ocean . SST changes diurnally , like the air above it , but to a lesser degree . There is less SST variation on breezy days than on calm days . In addition , ocean currents such as the Atlantic Multidecadal Oscillation ( AMO ) , can effect SST 's on multi-decadal time scales , a major impact results from the global thermohaline circulation , which affects average SST significantly throughout most of the world 's oceans . Coastal SSTs can cause offshore winds to generate upwelling , which can significantly cool or warm nearby landmasses , but shallower waters over a continental shelf are often warmer . Onshore winds can cause a considerable warm-up even in areas where upwelling is fairly constant , such as the northwest coast of South America . Its values are important within numerical weather prediction as the SST influences the atmosphere above , such as in the formation of sea breezes and sea fog . It is also used to calibrate measurements from weather satellites . |
2214 | Cooling_tower | "We found [U.S. weather] stations located next to the exhaust fans of air conditioning units, surrounded by asphalt parking lots and roads, on blistering-hot rooftops, and near sidewalks and buildings that absorb and radiate heat. | Cooling tower A cooling tower is a heat rejection device that rejects waste heat to the atmosphere through the cooling of a water stream to a lower temperature . Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or , in the case of closed circuit dry cooling towers , rely solely on air to cool the working fluid to near the dry-bulb air temperature . Common applications include cooling the circulating water used in oil refineries , petrochemical and other chemical plants , thermal power stations and HVAC systems for cooling buildings . The classification is based on the type of air induction into the tower : the main types of cooling towers are natural draft and induced draft cooling towers . Cooling towers vary in size from small roof-top units to very large hyperboloid structures ( as in the adjacent image ) that can be up to 200 m tall and 100 m in diameter , or rectangular structures that can be over 40 m tall and 80 m long . The hyperboloid cooling towers are often associated with nuclear power plants , although they are also used in some coal-fired plants and to some extent in some large chemical and other industrial plants . Although these large towers are very prominent , the vast majority of cooling towers are much smaller , including many units installed on or near buildings to discharge heat from air conditioning . |
1785 | El_Niño–Southern_Oscillation | Global surface temperatures have continued to rise steadily beneath short-term natural cooling effects, and the rise in global heat content has not slowed at all. | El Niño–Southern Oscillation El Niño -- Southern Oscillation ( ENSO ) is an irregularly periodical variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean , affecting much of the tropics and subtropics . The warming phase is known as El Niño and the cooling phase as La Niña . Southern Oscillation is the accompanying atmospheric component , coupled with the sea temperature change : El Niño is accompanied with high , and La Niña with low air surface pressure in the tropical western Pacific . The two periods last several months each ( typically occur every few years ) and their effects vary in intensity . The two phases relate to the Walker circulation , discovered by Gilbert Walker during the early twentieth century . The Walker circulation is caused by the pressure gradient force that results from a high pressure system over the eastern Pacific Ocean , and a low pressure system over Indonesia . When the Walker circulation weakens or reverses , an El Niño results , causing the ocean surface to be warmer than average , as upwelling of cold water occurs less or not at all . An especially strong Walker circulation causes a La Niña , resulting in cooler ocean temperatures due to increased upwelling . Mechanisms that cause the oscillation remain under study . The extremes of this climate pattern 's oscillations cause extreme weather ( such as floods and droughts ) in many regions of the world . Developing countries dependent upon agriculture and fishing , particularly those bordering the Pacific Ocean , are the most affected . |
2255 | Ice_age | And since the last ice age ended almost exactly 11,500 years ago…" (Ice Age Now) | 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 . |
2726 | Fossil_fuel | Humans are emitting 26 gigatonnes of CO2 into the atmosphere. | Fossil fuel Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms , containing energy originating in ancient photosynthesis . The age of the organisms and their resulting fossil fuels is typically millions of years , and sometimes exceeds 650 million years . Fossil fuels contain high percentages of carbon and include petroleum , coal , and natural gas . Other commonly used derivatives include kerosene and propane . Fossil fuels range from volatile materials with low carbon to hydrogen ratios like methane , to liquids like petroleum , to nonvolatile materials composed of almost pure carbon , like anthracite coal . Methane can be found in hydrocarbon fields either alone , associated with oil , or in the form of methane clathrates . The theory that fossil fuels formed from the fossilized remains of dead plants by exposure to heat and pressure in the Earth 's crust over millions of years was first introduced by Georgius Agricola in 1556 and later by Mikhail Lomonosov in the 18th century . The Energy Information Administration estimates that in 2007 the primary sources of energy consisted of petroleum 36.0 % , coal 27.4 % , natural gas 23.0 % , amounting to an 86.4 % share for fossil fuels in primary energy consumption in the world . Non-fossil sources in 2006 included nuclear 8.5 % , hydroelectric 6.3 % , and others ( geothermal , solar , tidal , wind , wood , waste ) amounting to 0.9 % . World energy consumption was growing about 2.3 % per year . Although fossil fuels are continually being formed via natural processes , they are generally considered to be non-renewable resources because they take millions of years to form and the known viable reserves are being depleted much faster than new ones are being made . The use of fossil fuels raises serious environmental concerns . The burning of fossil fuels produces around 21.3 billion tonnes ( 21.3 gigatonnes ) of carbon dioxide ( CO2 ) per year . It is estimated that natural processes can only absorb about half of that amount , so there is a net increase of 10.65 billion tonnes of atmospheric carbon dioxide per year . Carbon dioxide is a greenhouse gas that increases radiative forcing and contributes to global warming . A global movement towards the generation of renewable energy is underway to help reduce global greenhouse gas emissions . |
2494 | Global_warming | There is ample evidence that Earth's average temperature has increased in the past 100 years and the decline of mid- and high-latitude glaciers is a major piece of evidence. | 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 . |
2959 | Scientific_consensus_on_climate_change | Even if the warming were as big as the IPCC imagines, it would not be as dangerous as Mr. Brown suggests. | 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. |
551 | Oceanic_climate | Gone are the days when scientists drew a bright line dividing weather and climate. | Oceanic climate An oceanic climate ( also known as marine , west coast and maritime ) is the Köppen classification of the climate typical of west coasts in higher middle latitudes of continents , and generally features cool summers ( relative to their latitude ) and cool but not cold winters , with a relatively narrow annual temperature range and few extremes of temperature , with the exception for transitional areas to continental , subarctic and highland climates . Oceanic climates are defined as having a monthly mean temperature below 22 C in the warmest month , and above 0 C in the coldest month . It typically lacks a dry season , as precipitation is more evenly dispersed throughout the year . It is the predominant climate type across much of North Western Europe , the Pacific Northwest region of the United States and Canada , portions of southwestern South America and small areas of southeast Australia , and New Zealand as well as isolated locations elsewhere . Oceanic climates generally have cool summers and cool ( but not cold ) winters . They are characterised by a narrower annual range of temperatures than are encountered in other places at a comparable latitude , and generally do not have the extremely dry summers of Mediterranean climates or the hot summers of humid subtropical . Oceanic climates are most dominant in Europe , where they spread much farther inland than in other continents . Oceanic climates can have much storm activity as they are located in the belt of the stormy westerlies . Many oceanic climates have frequent cloudy or overcast conditions due to the near constant storms and lows tracking over or near them . The annual range of temperatures is smaller than typical climates at these latitudes due to the constant stable marine air masses that pass through oceanic climates , which lack both very warm and very cool fronts . |
1454 | Indian_Ocean | The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of more than 0.4 degrees Fahrenheit since 1969. | Indian Ocean The Indian Ocean is the third largest of the world 's oceanic divisions , covering 70,560,000 km2 ( approximately 20 % of the water on the Earth 's surface ) . It is bounded by Asia on the north , on the west by Africa , on the east by Australia , and on the south by the Southern Ocean or , depending on definition , by Antarctica . It is named after India . The Indian Ocean is known as Ratnākara , `` the mine of gems '' in ancient Sanskrit literature , and as Hind Mahāsāgar , in Hindi . |
127 | Climate_change_and_agriculture | Increased atmospheric carbon dioxide has helped raise global food production and reduce poverty. | 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 . |
2605 | United_Nations_Environment_Programme | "A United Nations report has identified the world's rapidly growing herds of cattle as the greatest threat to the climate, forests and wildlife. ... | United Nations Environment Programme The United Nations Environment Programme ( UN Environment ) is an agency of United Nations and coordinates its environmental activities , assisting developing countries in implementing environmentally sound policies and practices . It was founded by Maurice Strong , its first director , as a result of the United Nations Conference on the Human Environment ( Stockholm Conference ) in June 1972 and has its headquarters in the Gigiri neighbourhood of Nairobi , Kenya . UN Environment also has six regional offices and various country offices . UN Environment has overall responsibility for environmental problems among United Nations agencies but international talks on specialized issues , such as addressing global warming or combating desertification , are overseen by other UN organizations , like the Bonn-based Secretariat of the United Nations Framework Convention on Climate Change and the United Nations Convention to Combat Desertification . UN Environment activities cover a wide range of issues regarding the atmosphere , marine and terrestrial ecosystems , environmental governance and green economy . It has played a significant role in developing international environmental conventions , promoting environmental science and information and illustrating the way those can be implemented in conjunction with policy , working on the development and implementation of policy with national governments , regional institutions in conjunction with environmental non-governmental organizations ( NGOs ) . UN Environment has also been active in funding and implementing environment related development projects . UN Environment has aided in the formulation of guidelines and treaties on issues such as the international trade in potentially harmful chemicals , transboundary air pollution , and contamination of international waterways . The World Meteorological Organization and UN Environment established the Intergovernmental Panel on Climate Change ( IPCC ) in 1988 . UN Environment is also one of several Implementing Agencies for the Global Environment Facility ( GEF ) and the Multilateral Fund for the Implementation of the Montreal Protocol , and it is also a member of the United Nations Development Group . The International Cyanide Management Code , a program of best practice for the chemical 's use at gold mining operations , was developed under UN Environment 's aegis . |
1235 | Quaternary_glaciation | "During ice ages, caused by wobbles in the Earth's orbit, sea levels dropped more than 400 feet as ice piled up on land. | Quaternary glaciation The Quaternary glaciation , also known as the Pleistocene glaciation or the current ice age , is a series of glacial events separated by interglacial events during the Quaternary period from 2.58 Ma ( million years ago ) to present . During this period , ice sheets expanded , notably from out of Antarctica and Greenland , and fluctuating ice sheets occurred elsewhere ( for example , the Laurentide ice sheet ) . The major effects of the ice age are erosion and deposition of material over large parts of the continents , modification of river systems , creation of millions of lakes , changes in sea level , development of pluvial lakes far from the ice margins , isostatic adjustment of the crust , and abnormal winds . It affected oceans , flooding , and biological communities . The ice sheets themselves , by raising the albedo , affect a major feedback on climate cooling . |
626 | Sea_level_rise | The trend has been measured by a network of tidal gauges, many of which have been collecting data for over a century. | 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 . |
2009 | Sarah_Palin | Top Scientist Hal Lewis Resigns Over Climate Change Corruption | Sarah Palin Sarah Louise Palin ( -LSB- ˈpeɪlᵻn -RSB- née Heath ; born February 11 , 1964 ) is an American politician , commentator , and author who served as the ninth Governor of Alaska from 2006 until her resignation in 2009 . As the Republican Party nominee for Vice President of the United States in the 2008 election alongside presidential nominee , Arizona Senator John McCain , she was the first Alaskan on the national ticket of a major political party and the first Republican woman selected as a vice presidential candidate . Also , her book Going Rogue has sold more than two million copies . She was elected to the Wasilla city council in 1992 and became mayor of Wasilla in 1996 . In 2003 , after an unsuccessful run for lieutenant governor , she was appointed chair of the Alaska Oil and Gas Conservation Commission , responsible for overseeing the state 's oil and gas fields for safety and efficiency . She was the youngest person and the first woman to be elected Governor of Alaska . Since her resignation as Governor , she has endorsed and campaigned for the Tea Party movement as well as several candidates in multiple election cycles , prominently including Donald Trump for President in 2016 . From 2010 to 2015 , she provided political commentary for Fox News . On April 3 , 2014 , Palin premiered her TV show , Amazing America with Sarah Palin , on the Sportsman Channel , which ran until February 12 , 2015 . On July 27 , 2014 , Palin launched the online news network called the Sarah Palin Channel , which was closed on July 4 , 2015 . |
2000 | Ted_Cruz | There is not a single candidate in the Republican primary that thinks we should do anything about climate change. | Ted Cruz Rafael Edward `` Ted '' Cruz -LSB- ˈkruːz -RSB- ( born December 22 , 1970 ) is an American politician and attorney , who has served as the junior United States Senator from Texas since 2013 . He was a candidate for the Republican nomination for President of the United States in the 2016 election . Cruz graduated from Princeton University , New Jersey , in 1992 , and from Harvard Law School , Massachusetts , in 1995 . From 1999 to 2003 , he served in various political appointee positions : the Director of the Office of Policy Planning at the Federal Trade Commission ( FTC ) , an Associate Deputy Attorney General at the United States Department of Justice , and a Domestic Policy Advisor to George W. Bush on the 2000 George W. Bush Presidential campaign . Cruz served as Solicitor General of Texas , from 2003 to 2008 , appointed by Texas Attorney General , Greg Abbott . He was the first Hispanic , and the longest-serving , Solicitor General in Texas history . From 2004 to 2009 , Cruz was an Adjunct Professor at the University of Texas School of Law in Austin , Texas , where he taught U.S. Supreme Court litigation . Cruz ran for the Senate seat vacated by fellow Republican Kay Bailey Hutchison and , in July 2012 , defeated Lieutenant Governor David Dewhurst during the Republican primary runoff , 57 -- 43 % . He defeated former State Representative Paul Sadler in the November 2012 general election , winning 56 -- 41 % . He is the first Hispanic American to serve as a U.S. Senator representing Texas , and is one of three senators of Cuban descent . He chairs the Senate Judiciary Subcommittee on Oversight , Federal Rights and Agency Activities , and is the Chairman of the Senate Commerce Subcommittee on Space , Science and Competitiveness . In November 2012 , he was appointed Vice-Chairman of the National Republican Senatorial Committee . Cruz began campaigning for the Republican presidential nomination in March 2015 . During the primary campaign , his base of support was strongest with `` women , white evangelical Protestants , people over the age of 50 , and those who identified themselves as conservatives '' , though he had crossover appeal to other factions within his party , including libertarian conservatives and millennials . Cruz 's victory in the February 2016 Iowa caucuses marked the first time a Hispanic person won a U.S. presidential caucus or primary . He eventually emerged as the main challenger to frontrunner Donald Trump . He suspended his campaign for president on May 3 , 2016 , after losing the Republican primary in Indiana to Trump . |
1616 | John_Christy | UAH atmospheric temperatures prove climate models and/or surface temperature data sets are wrong. | John Christy John Raymond Christy is a climate scientist at the University of Alabama in Huntsville ( UAH ) whose chief interests are satellite remote sensing of global climate and global climate change . He is best known , jointly with Roy Spencer , for the first successful development of a satellite temperature record . |
1083 | Rock_music | 'Getting hung up on the exact nature of the records is interesting, and there's lots of technical work that can be done there, but the main take-home response there is that the trends we've been seeing since the 1970s are continuing and have not paused in any way,' he said." | Rock music Rock music is a genre of popular music that originated as `` rock and roll '' in the United States in the early 1950s , and developed into a range of different styles in the 1960s and later , particularly in the United Kingdom and the United States . It has its roots in 1940s and 1950s rock and roll , a style which drew heavily on the African-American genres of blues and rhythm and blues , and from country music . Rock music also drew strongly on a number of other genres such as electric blues and folk , and incorporated influences from jazz , classical and other musical styles . Musically , rock has centered on the electric guitar , usually as part of a rock group with electric bass and drums and one or more singers . Typically , rock is song-based music usually with a 4/4 time signature using a verse-chorus form , but the genre has become extremely diverse . Like pop music , lyrics often stress romantic love but also address a wide variety of other themes that are frequently social or political . By the late 1960s `` classic rock '' period , a number of distinct rock music subgenres had emerged , including hybrids like blues rock , folk rock , country rock , raga rock , and jazz-rock , many of which contributed to the development of psychedelic rock , which was influenced by the countercultural psychedelic and hippie scene . New genres that emerged included progressive rock , which extended the artistic elements ; glam rock , which highlighted showmanship and visual style ; and the diverse and enduring subgenre of heavy metal , which emphasized volume , power , and speed . In the second half of the 1970s , punk rock reacted by producing stripped-down , energetic social and political critiques . Punk was an influence in the 1980s on new wave , post-punk and eventually alternative rock . From the 1990s alternative rock began to dominate rock music and break into the mainstream in the form of grunge , Britpop , and indie rock . Further fusion subgenres have since emerged , including pop punk , rap rock , and rap metal , as well as conscious attempts to revisit rock 's history , including the garage rock/post-punk and synth-pop revivals at the beginning of the 2000s ( decade ) . Rock music has also embodied and served as the vehicle for cultural and social movements , leading to major subcultures including mods and rockers in the UK and the hippie counterculture that spread out from San Francisco in the US in the 1960s . Similarly , 1970s punk culture spawned the goth and emo subcultures . Inheriting the folk tradition of the protest song , rock music has been associated with political activism as well as changes in social attitudes to race , sex and drug use , and is often seen as an expression of youth revolt against adult consumerism and conformity . |
508 | Future_of_Earth | Climate projections also assume that planet Earth is not dynamic | Future of Earth The biological and geological future of Earth can be extrapolated based upon the estimated effects of several long-term influences . These include the chemistry at Earth 's surface , the rate of cooling of the planet 's interior , the gravitational interactions with other objects in the Solar System , and a steady increase in the Sun 's luminosity . An uncertain factor in this extrapolation is the ongoing influence of technology introduced by humans , such as climate engineering , which could cause significant changes to the planet . The current Holocene extinction is being caused by technology and the effects may last for up to five million years . In turn , technology may result in the extinction of humanity , leaving the planet to gradually return to a slower evolutionary pace resulting solely from long-term natural processes . Over time intervals of hundreds of millions of years , random celestial events pose a global risk to the biosphere , which can result in mass extinctions . These include impacts by comets or asteroids with diameters of 5 -- or more , and the possibility of a massive stellar explosion , called a supernova , within a 100-light-year radius of the Sun , called a Near-Earth supernova . Other large-scale geological events are more predictable . If the long-term effects of global warming are disregarded , Milankovitch theory predicts that the planet will continue to undergo glacial periods at least until the Quaternary glaciation comes to an end . These periods are caused by variations in eccentricity , axial tilt , and precession of the Earth 's orbit . As part of the ongoing supercontinent cycle , plate tectonics will probably result in a supercontinent in 250 -- 350 million years . Some time in the next 1.5 -- 4.5 billion years , the axial tilt of the Earth may begin to undergo chaotic variations , with changes in the axial tilt of up to 90 ° . During the next four billion years , the luminosity of the Sun will steadily increase , resulting in a rise in the solar radiation reaching the Earth . This will result in a higher rate of weathering of silicate minerals , which will cause a decrease in the level of carbon dioxide in the atmosphere . In about 600 million years from now , the level of CO2 will fall below the level needed to sustain C3 carbon fixation photosynthesis used by trees . Some plants use the C4 carbon fixation method , allowing them to persist at concentrations as low as 10 parts per million . However , the long-term trend is for plant life to die off altogether . The extinction of plants will be the demise of almost all animal life , since plants are the base of the food chain on Earth . In about one billion years , the solar luminosity will be 10 % higher than at present . This will cause the atmosphere to become a `` moist greenhouse '' , resulting in a runaway evaporation of the oceans . As a likely consequence , plate tectonics will come to an end , and with them the entire carbon cycle . Following this event , in about 2 − 3 billion years , the planet 's magnetic dynamo may cease , causing the magnetosphere to decay and leading to an accelerated loss of volatiles from the outer atmosphere . Four billion years from now , the increase in the Earth 's surface temperature will cause a runaway greenhouse effect , heating the surface enough to melt it . By that point , all life on the Earth will be extinct . The most probable fate of the planet is absorption by the Sun in about 7.5 billion years , after the star has entered the red giant phase and expanded to cross the planet 's current orbit . |
474 | Arctic_ice_pack | Sea ice continued its declining trend, both in the Arctic and Antarctic. | Arctic ice pack The Arctic ice pack is the ice cover of the Arctic Ocean and its vicinity . The Arctic ice pack undergoes a regular seasonal cycle in which ice melts in spring and summer , reaches a minimum around mid-September , then increases during fall and winter . Summer ice cover in the Arctic is about 50 % of winter cover . Some of the ice survives from one year to the next . Currently 28 % of Arctic basin sea ice is multi-year ice , thicker than seasonal ice : up to 3 - thick over large areas , with ridges up to 20 m thick . As well as the regular seasonal cycle there has been an underlying trend of declining sea ice in the Arctic in recent decades . |
3131 | Effects_of_global_warming | We don't need a high heat flow - just a high temperature for the core to affect the surface climate. | 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 . |
1504 | Hurricane_Harvey | Climate scientists say that aspects of the case of Hurricane Harvey suggest global warming is making a bad situation worse. | 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 |
240 | Intergovernmental_Panel_on_Climate_Change | In 1990 the United Nation's Intergovernmental Panel on Climate Change (IPCC) predicted that temperatures would rise by 0.54F (0.3C) per decade. | Intergovernmental Panel on Climate Change The Intergovernmental Panel on Climate Change ( IPCC ) is a scientific and intergovernmental body under the auspices of the United Nations , set up at the request of member governments , dedicated to the task of providing the world with an objective , scientific view of climate change and its political and economic impacts . It was first established in 1988 by two United Nations organizations , the World Meteorological Organization ( WMO ) and the United Nations Environment Programme ( UNEP ) , and later endorsed by the United Nations General Assembly through Resolution 43/53 . Membership of the IPCC is open to all members of the WMO and UNEP . The IPCC produces reports that support the United Nations Framework Convention on Climate Change ( UNFCCC ) , which is the main international treaty on climate change . The ultimate objective of the UNFCCC is to `` stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic -LSB- i.e. , human-induced -RSB- interference with the climate system '' . IPCC reports cover `` the scientific , technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change , its potential impacts and options for adaptation and mitigation . '' The IPCC does not carry out its own original research , nor does it do the work of monitoring climate or related phenomena itself . The IPCC bases its assessment on the published literature , which includes peer-reviewed and non-peer-reviewed sources . Thousands of scientists and other experts contribute ( on a voluntary basis , without payment from the IPCC ) to writing and reviewing reports , which are then reviewed by governments . IPCC reports contain a `` Summary for Policymakers '' , which is subject to line-by-line approval by delegates from all participating governments . Typically this involves the governments of more than 120 countries . The IPCC provides an internationally accepted authority on climate change , producing reports which have the agreement of leading climate scientists and the consensus of participating governments . The 2007 Nobel Peace Prize was shared , in equal parts , between the IPCC and Al Gore . |
697 | Machine_learning | While many scientists have acknowledged the mismatch between model predictions and actual temperature observations, few have really challenged the validity of the models themselves. | Machine learning Machine learning is the subfield of computer science that , according to Arthur Samuel in 1959 , gives `` computers the ability to learn without being explicitly programmed . '' Evolved from the study of pattern recognition and computational learning theory in artificial intelligence , machine learning explores the study and construction of algorithms that can learn from and make predictions on data -- such algorithms overcome following strictly static program instructions by making data-driven predictions or decisions , through building a model from sample inputs . Machine learning is employed in a range of computing tasks where designing and programming explicit algorithms with good performance is difficult or unfeasible ; example applications include email filtering , detection of network intruders or malicious insiders working towards a data breach , optical character recognition ( OCR ) , learning to rank and computer vision . Machine learning is closely related to ( and often overlaps with ) computational statistics , which also focuses on prediction-making through the use of computers . It has strong ties to mathematical optimization , which delivers methods , theory and application domains to the field . Machine learning is sometimes conflated with data mining , where the latter subfield focuses more on exploratory data analysis and is known as unsupervised learning . Machine learning can also be unsupervised and be used to learn and establish baseline behavioral profiles for various entities and then used to find meaningful anomalies . Within the field of data analytics , machine learning is a method used to devise complex models and algorithms that lend themselves to prediction ; in commercial use , this is known as predictive analytics . These analytical models allow researchers , data scientists , engineers , and analysts to `` produce reliable , repeatable decisions and results '' and uncover `` hidden insights '' through learning from historical relationships and trends in the data . , machine learning is a buzzword , and according to the Gartner hype cycle of 2016 , at its peak of inflated expectations . Because finding patterns is hard , often not enough training data is available , and also because of the high expectations it often fails to deliver . |
2826 | Cloud | A drop of volcanic activity in the early 20th century may have had a warming effect. | Cloud In meteorology , a cloud is an aerosol comprising a visible mass of minute liquid droplets , frozen crystals , or particles suspended in the atmosphere above the surface of a planetary body . The droplets and crystals may be made of water or various chemicals . On Earth , clouds are formed as a result of saturation of the air when it is cooled to its dew point , or when it gains sufficient moisture ( usually in the form of water vapor ) from an adjacent source to raise the dew point to the ambient temperature . They are seen in the Earth 's homosphere ( which includes the troposphere , stratosphere , and mesosphere ) . Nephology is the science of clouds which is undertaken in the cloud physics branch of meteorology . There are two systems of naming clouds in their respective layers of the atmosphere ; Latin in the troposphere and mostly alpha-numeric above the troposphere . Cloud types in the troposphere , the atmospheric layer closest to Earth 's surface , have Latin names due to the universal adaptation of Luke Howard 's nomenclature . Formally proposed in 1802 , it became the basis of a modern international system that classifies clouds into five physical forms and three altitude levels ( formerly known as étages ) . These physical types , in approximate ascending order of convective activity , include stratiform sheets , cirriform wisps and patches , stratocumuliform layers ( mainly structured as rolls , ripples , and patches ) , cumuliform heaps , and very large cumulonimbiform heaps that often show complex structure . The physical forms are cross-classified by the altitude levels to produce ten basic genus-types , most of which can be divided into species , and subdivided into varieties . Two cirriform clouds that form higher up in the stratosphere and mesosphere have common names for their main types , but are sub-classified alpha-numerically . They are relatively uncommon and are mostly seen in the polar regions of Earth . Clouds have been observed in the atmospheres of other planets and moons in the Solar System and beyond . However , due to their different temperature characteristics , they are often composed of other substances such as methane , ammonia , and sulfuric acid as well as water . Homospheric types determined by cross-classification of forms and levels . '' Homospheric types include the ten tropospheric genera and two additional major types above the troposphere . The cumulus genus includes three variants as defined by vertical size . |
2609 | Global_warming | Individual carbon dioxide molecules have a short life time of around 5 years in the atmosphere. | 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 . |
2243 | Greenhouse_effect | The CO2 amplifies the warming and mixes through the atmosphere, spreading warming throughout the planet. | Greenhouse effect The greenhouse effect is the process by which radiation from a planet 's atmosphere warms the planet 's surface to a temperature above what it would be without its atmosphere . If a planet 's atmosphere contains radiatively active gases ( i.e. , greenhouse gases ) the atmosphere will radiate energy in all directions . Part of this radiation is directed towards the surface , warming it . The downward component of this radiation -- that is , the strength of the greenhouse effect -- will depend on the atmosphere 's temperature and on the amount of greenhouse gases that the atmosphere contains . On Earth , the atmosphere is warmed by absorption of infrared thermal radiation from the underlying surface ( heated by the sun ) , absorption of shorter wavelength radiant energy from the sun , and convective heat fluxes from the surface . Greenhouse gases in the atmosphere radiate energy , some of which is directed to the surface and lower atmosphere . The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect . Earth 's natural greenhouse effect is critical to supporting life . Human activities , primarily the burning of fossil fuels and clearing of forests , have intensified the natural greenhouse effect , causing global warming . The mechanism is named after a faulty analogy with the effect of solar radiation passing through glass and warming a greenhouse . The way a greenhouse retains heat is fundamentally different , as a greenhouse works by reducing airflow and retaining warm air inside the structure . |
3049 | Global_warming | that atmospheric CO2 increase that we observe is a product of temperature increase, and not the other way around, meaning it is a product of natural variation... | 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 . |
470 | Instrumental_temperature_record | According to NASA, the globally averaged temperature of the land and ocean was 0.9˚C (1.62˚F) above the 20th century average. | Instrumental temperature record The instrumental temperature record provides the temperature of Earth 's climate system from the historical network of in situ measurements of surface air temperatures and ocean surface temperatures . Data are collected at thousands of meteorological stations , buoys and ships around the globe . The longest-running temperature record is the Central England temperature data series , that starts in 1659 . The longest-running quasi-global record starts in 1850 . In recent decades more extensive sampling of ocean temperatures at various depths have begun allowing estimates of ocean heat content but these do not form part of the global surface temperature datasets . |
1223 | Retreat_of_glaciers_since_1850 | Ice cap is disappearing far more rapidly than previously estimated, and is part of a long-term trend, new research shows | 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 . |
724 | Sustainable_energy | A fast transition away from fossil fuels in the next few decades could be enough to put off rapid sea-level rise for centuries. | Sustainable energy Sustainable energy is energy that is consumed at insignificant rates compared to its supply and with manageable collateral effects , especially environmental effects . Another common definition of sustainable energy is an energy system that serves the needs of the present without compromising the ability of future generations to meet their needs . The organizing principle for sustainability is sustainable development , which includes the four interconnected domains : ecology , economics , politics and culture . Sustainability science is the study of sustainable development and environmental science . Technologies promote sustainable energy including renewable energy sources , such as hydroelectricity , solar energy , wind energy , wave power , geothermal energy , bioenergy , tidal power and also technologies designed to improve energy efficiency . Costs have fallen dramatically in recent years , and continue to fall . Most of these technologies are either economically competitive or close to being so . Increasingly , effective government policies support investor confidence and these markets are expanding . Considerable progress is being made in the energy transition from fossil fuels to ecologically sustainable systems , to the point where many studies support 100 % renewable energy . |
1519 | Earth | The Earth's climate is changing in response to increasing concentrations of greenhouse gases (GHGs) and particulate matter in the atmosphere, largely as the result of human activities. | 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 . |
2591 | Carbon_dioxide | We now know that the planetary energy balance is determined by the upper levels of the troposphere and that the saturation of the absorption at the central frequency does not preclude the possibility to absorb more energy. | 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 . |
1120 | Arctic_sea_ice_decline | The connection between the vanishing Arctic ice and extreme summer weather in the northern hemisphere is probable, according to scientists, but not yet as certain as the winter link. | Arctic sea ice decline Arctic sea ice decline is the sea ice loss observed in recent decades in the Arctic Ocean . The Intergovernmental Panel on Climate Change ( IPCC ) Fourth Assessment Report states that greenhouse gas forcing is largely , but not wholly , responsible for the decline in Arctic sea ice extent . A study from 2011 suggested that internal variability enhanced the greenhouse gas forced sea ice decline over the last decades . A study from 2007 found the decline to be `` faster than forecasted '' by model simulations . The IPCC Fifth Assessment Report concluded with high confidence that sea ice continues to decrease in extent , and that there is robust evidence for the downward trend in Arctic summer sea ice extent since 1979 . It has been established that the region is at its warmest for at least 40,000 years and the Arctic-wide melt season has lengthened at a rate of 5 days per decade ( from 1979 to 2013 ) , dominated by a later autumn freezeup . Sea ice changes have been identified as a mechanism for polar amplification . |
2187 | Climatology | Scientific analysis of past climates shows that greenhouse gasses, principally CO2, have controlled most ancient climate changes. | Climatology Climatology ( from Greek κλίμα , klima , `` place , zone '' ; and - λογία , - logia ) or climate science is the study of climate , scientifically defined as weather conditions averaged over a period of time . This modern field of study is regarded as a branch of the atmospheric sciences and a subfield of physical geography , which is one of the Earth sciences . Climatology now includes aspects of oceanography and biogeochemistry . Basic knowledge of climate can be used within shorter term weather forecasting using analog techniques such as the El Niño -- Southern Oscillation ( ENSO ) , the Madden -- Julian oscillation ( MJO ) , the North Atlantic oscillation ( NAO ) , the Northern Annular Mode ( NAM ) which is also known as the Arctic oscillation ( AO ) , the Northern Pacific ( NP ) Index , the Pacific decadal oscillation ( PDO ) , and the Interdecadal Pacific Oscillation ( IPO ) . Climate models are used for a variety of purposes from study of the dynamics of the weather and climate system to projections of future climate . Weather is known as the condition of the atmosphere over a period of time . While Climate has to do with the atmospheric condition over an extended to indefinite period of time . |
1506 | Climate_change_and_ecosystems | Most likely the primary control knob on climate change is the ocean waters and this environment that we live in. | Climate change and ecosystems This article is about climate change and ecosystems . |
3024 | Negative_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. | Negative feedback Negative feedback occurs when some function of the output of a system , process , or mechanism is fed back in a manner that tends to reduce the fluctuations in the output , whether caused by changes in the input or by other disturbances . Whereas positive feedback tends to lead to instability via exponential growth , oscillation or chaotic behavior , negative feedback generally promotes stability . Negative feedback tends to promote a settling to equilibrium , and reduces the effects of perturbations . Negative feedback loops in which just the right amount of correction is applied with optimum timing can be very stable , accurate , and responsive . Negative feedback is widely used in mechanical and electronic engineering , but it also occurs naturally within living organisms , and can be seen in many other fields from chemistry and economics to physical systems such as the climate . General negative feedback systems are studied in control systems engineering . |
1917 | Global_warming | May 2018 marked the 401st straight month of global temperatures exceeding the 20th century average. | 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 . |
1722 | Carbon_dioxide | Humans are small but powerful, and human CO2 emissions are causing global warming. | 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 . |
1141 | Antarctica | "While record low sea ice is nothing new in the Arctic, this is a surprising turn of events for the Antarctic. | Antarctica Antarctica ( UK English -LSB- ænˈtɑːktɪkə -RSB- or -LSB- ænˈtɑːtɪkə -RSB- , US English -LSB- æntˈɑːrktɪkə -RSB- ) is Earth 's southernmost continent . It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere , almost entirely south of the Antarctic Circle , and is surrounded by the Southern Ocean . At 14000000 km2 , it is the fifth-largest continent . For comparison , Antarctica is nearly twice the size of Australia . About 98 % of Antarctica is covered by ice that averages 1.9 km in thickness , which extends to all but the northernmost reaches of the Antarctic Peninsula . Antarctica , on average , is the coldest , driest , and windiest continent , and has the highest average elevation of all the continents . Antarctica is a desert , with annual precipitation of only 200 mm ( 8 in ) along the coast and far less inland . The temperature in Antarctica has reached − 89.2 ° C ( − 128.6 ° F ) , though the average for the third quarter ( the coldest part of the year ) is − 63 ° C ( − 81 ° F ) . Anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent . Organisms native to Antarctica include many types of algae , bacteria , fungi , plants , protista , and certain animals , such as mites , nematodes , penguins , seals and tardigrades . Vegetation , where it occurs , is tundra . Although myths and speculation about a Terra Australis ( `` Southern Land '' ) date back to antiquity , Antarctica is noted as the last region on Earth in recorded history to be discovered and colonised by humans , being only first sighted in 1820 by the Russian expedition of Fabian Gottlieb von Bellingshausen and Mikhail Lazarev on Vostok and Mirny , who sighted the Fimbul ice shelf . The continent , however , remained largely neglected for the rest of the 19th century because of its hostile environment , lack of easily accessible resources , and isolation . In 1895 , the first confirmed landing was conducted by a team of Norwegians . Antarctica is a de facto condominium , governed by parties to the Antarctic Treaty System that have consulting status . Twelve countries signed the Antarctic Treaty in 1959 , and thirty-eight have signed it since then . The treaty prohibits military activities and mineral mining , prohibits nuclear explosions and nuclear waste disposal , supports scientific research , and protects the continent 's ecozone . Ongoing experiments are conducted by more than 4,000 scientists from many nations . |
2588 | Carbon_dioxide_in_Earth's_atmosphere | However, satellite and surface measurements observe an enhanced greenhouse effect at the wavelengths that CO2 absorb energy. | Carbon dioxide in Earth's atmosphere Carbon dioxide is an important trace gas in Earth 's atmosphere . Currently it constitutes about 0.041 % ( equal to 410 parts per million ; ppm ) by volume of the atmosphere . Despite its relatively small concentration is a potent greenhouse gas and plays a vital role in regulating Earth 's surface temperature through radiative forcing and the greenhouse effect . Reconstructions show that concentrations of in the atmosphere have varied , ranging from as high as 7,000 ppm during the Cambrian period about 500 million years ago to as low as 180 ppm during the Quaternary glaciation of the last two million years . Carbon dioxide is an integral part of the carbon cycle , a biogeochemical cycle in which carbon is exchanged between the Earth 's oceans , soil , rocks and the biosphere . Plants and other photoautotrophs use solar energy to produce carbohydrate from atmospheric carbon dioxide and water by photosynthesis . Almost all other organisms depend on carbohydrate derived from photosynthesis as their primary source of energy and carbon compounds . The current episode of global warming is attributed to increasing emissions of and other greenhouse gases into Earth 's atmosphere . The global annual mean concentration of in the atmosphere has increased by more than 40 % since the start of the Industrial Revolution , from 280 ppm , the level it had for the last 10,000 years leading up to the mid-18th century , to 399 ppm as of 2015 . The present concentration is the highest in at least the past 800,000 years and likely the highest in the past 20 million years . The increase has been caused by anthropogenic sources , particularly the burning of fossil fuels and deforestation . The daily average concentration of atmospheric CO2 at Mauna Loa Observatory first exceeded 400 ppm on 10 May 2013 . It is currently rising at a rate of approximately 2 ppm/year and accelerating . An estimated 30 -- 40 % of the released by humans into the atmosphere dissolves into oceans , rivers and lakes , which contributes to ocean acidification . |
67 | Beringia | Fifty-five thousand years ago the whole world was 2°C warmer than it is today[...] | Beringia Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia ; on the east by the Mackenzie River in Canada ; on the north by 72 degrees north latitude in the Chukchi Sea ; and on the south by the tip of the Kamchatka Peninsula . It includes the Chukchi Sea , the Bering Sea , the Bering Strait , the Chukchi and Kamchatka Peninsulas in Russia as well as Alaska in the United States . The area includes land lying on the North American Plate and Siberian land east of the Chersky Range . Historically , it formed a land bridge that was up to 1000 km wide at its greatest extent and which covered an area as large as British Columbia and Alberta together , totaling at approximately 1600000 km2 . Today , the only land that is visible from the central part of the Bering land bridge are the Diomede Islands , the Pribilof Islands of St. Paul and St. George , St. Lawrence Island , and King Island . The term Beringia was coined by the Swedish botanist Eric Hultén in 1937 . During the ice ages , Beringia , like most of Siberia and all of North and Northeast China , was not glaciated because snowfall was very light . It was a grassland steppe , including the land bridge , that stretched for hundreds of kilometres into the continents on either side . It is believed that a small human population of at most a few thousand arrived in Beringia from eastern Siberia during the Last Glacial Maximum before expanding into the settlement of the Americas sometime after 16,500 years ago during the Late Glacial Maximum as the American glaciers blocking the way southward melted , but before the bridge was covered by the sea about 11,000 years BP . Before European colonization , Beringia was inhabited by the Yupik peoples on both sides of the straits . This culture remains in the region today along with others . In 2012 , the governments of Russia and the United States announced a plan to formally establish `` a transboundary area of shared Beringian heritage '' . Among other things this agreement would establish close ties between the Bering Land Bridge National Preserve and the Cape Krusenstern National Monument in the United States and the planned Beringia National Park in Russia . |
741 | Geology | For that, we have to work on other types of marine organisms so that we clearly understand what took place in the sediment over geological time" | Geology Geology ( from the Ancient Greek γῆ , gē , i.e. `` earth '' and - λoγία , - logia , i.e. `` study of , discourse '' ) is an earth science concerned with the solid Earth , the rocks of which it is composed , and the processes by which they change over time . Geology can also refer generally to the study of the solid features of any terrestrial planet ( such as the geology of the Moon or Mars ) . Geology gives insight into the history of the Earth by providing the primary evidence for plate tectonics , the evolutionary history of life , and past climates . Geology is important for mineral and hydrocarbon exploration and exploitation , evaluating water resources , understanding of natural hazards , the remediation of environmental problems , and for providing insights into past climate change . Geology also plays a role in geotechnical engineering and is a major academic discipline . |
2222 | Cretaceous–Paleogene_extinction_event | A large number of ancient mass extinction events have been strongly linked to global climate change. | Cretaceous–Paleogene extinction event The Cretaceous -- Paleogene ( K -- Pg ) extinction event , also known as the Cretaceous -- Tertiary ( K -- T ) extinction , was a mass extinction of some three-quarters of the plant and animal species on Earth that occurred over a geologically short period of time approximately 65 million years ago . With the exception of some ectothermic species like the leatherback sea turtle and crocodiles , no tetrapods weighing more than 25 kg survived . It marked the end of the Cretaceous period and with it , the entire Mesozoic Era , opening the Cenozoic Era that continues today . In the geologic record , the K -- Pg event is marked by a thin layer of sediment called the K -- Pg boundary , which can be found throughout the world in marine and terrestrial rocks . The boundary clay shows high levels of the metal iridium , which is rare in the Earth 's crust but abundant in asteroids . As originally proposed in 1980 by a team of scientists led by Luis Alvarez , it is now generally thought that the K -- Pg extinction was caused by a massive comet or asteroid impact , estimated to be 10 km wide , 66 million years ago and its catastrophic effects on the global environment , including a lingering impact winter that made it impossible for plants and plankton to carry out photosynthesis . The impact hypothesis , also known as the Alvarez hypothesis , was bolstered by the discovery of the 180 km Chicxulub crater in the Gulf of Mexico in the early 1990s , which provided conclusive evidence that the K -- Pg boundary clay represented debris from an asteroid impact . The fact that the extinctions occurred at the same time as the impact provides strong situational evidence that the K -- Pg extinction was caused by the asteroid . It was possibly accelerated by the creation of the Deccan Traps . However , some scientists maintain the extinction was caused or exacerbated by other factors , such as volcanic eruptions , climate change , or sea level change , separately or together . A wide range of species perished in the K -- Pg extinction . The best-known victims are the non-avian dinosaurs . However , the extinction also destroyed a plethora of other terrestrial organisms , including certain mammals , pterosaurs , birds , lizards , insects , and plants . In the oceans , the K -- Pg extinction killed off plesiosaurs and the giant marine lizards ( Mosasauridae ) and devastated fish , sharks , mollusks ( especially ammonites , which became extinct ) and many species of plankton . It is estimated that 75 % or more of all species on Earth vanished . Yet the devastation caused by the extinction also provided evolutionary opportunities . In the wake of the extinction , many groups underwent remarkable adaptive radiations -- a sudden and prolific divergence into new forms and species within the disrupted and emptied ecological niches resulting from the event . Mammals in particular diversified in the Paleogene , producing new forms such as horses , whales , bats , and primates . Birds , fish and perhaps lizards also radiated . |
2497 | Sierra_Madre_Occidental | Without the forests' humidity, previously moisture-laden winds blew dry. | Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera , that runs northwest -- southeast through Northwestern and Western Mexico , and along the Gulf of California . The Sierra Madre is part of the American Cordillera , a chain of mountain ranges ( cordillera ) that consists of an almost continuous sequence of mountain ranges that form the western `` backbone '' of North America , Central America , South America and Antarctica . |
2880 | Solar_power | For example, geothermal energy is available at all times, concentrated solar thermal energy has storage capability, and wind energy can be stored in compressed air. | Solar power Solar power is the conversion of energy from sunlight into electricity , either directly using photovoltaics ( PV ) , or indirectly using concentrated solar power . Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam . Photovoltaic cells convert light into an electric current using the photovoltaic effect . Photovoltaics were initially solely used as a source of electricity for small and medium-sized applications , from the calculator powered by a single solar cell to remote homes powered by an off-grid rooftop PV system . Commercial concentrated solar power plants were first developed in the 1980s . The 392 MW Ivanpah installation is the largest concentrating solar power plant in the world , located in the Mojave Desert of California . As the cost of solar electricity has fallen , the number of grid-connected solar PV systems has grown into the millions and utility-scale solar power stations with hundreds of megawatts are being built . Solar PV is rapidly becoming an inexpensive , low-carbon technology to harness renewable energy from the Sun . The current largest photovoltaic power station in the world is the 850 MW Longyangxia Dam Solar Park , in Qinghai , China . The International Energy Agency projected in 2014 that under its `` high renewables '' scenario , by 2050 , solar photovoltaics and concentrated solar power would contribute about 16 and 11 percent , respectively , of the worldwide electricity consumption , and solar would be the world 's largest source of electricity . Most solar installations would be in China and India . Currently , as of 2016 , solar power provides just 1 % of total worldwide electricity production but growing 33 % per annum . |
457 | Global_warming | temperatures rise and they fall, and they rise and they fall… and for the last 400 years we've had a gentle warming as we've been coming out of the little ice age. | 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 . |
822 | List_of_ecoregions_in_North_America_(CEC) | Climate policy must compete with other long-term threats for always-scarce resources." | List of ecoregions in North America (CEC) This list of ecoregions of North America provides an overview of North American ecoregions designated by the Commission for Environmental Cooperation ( CEC ) in its North American Environmental Atlas . It should not be confused with Wikipedia articles based on the classification system developed by the World Wildlife Fund , such as List of ecoregions ( WWF ) and Lists of ecoregions by country . The commission was established in 1994 by the member states of Canada , Mexico , and the United States to address regional environmental concerns under the North American Agreement on Environmental Cooperation ( NAAEC ) , the environmental side accord to the North American Free Trade Agreement ( NAFTA ) . The Commission 's 1997 report , Ecological Regions of North America , provides a framework that may be used by government agencies , non-governmental organizations , and academic researchers as a basis for risk analysis , resource management , and environmental study of the continent 's ecosystems . Ecoregions may be identified by similarities in geology , physiography , vegetation , climate soils , land use , wildlife distributions , and hydrology . The classification system has four levels . Only the first three levels are shown on this list . `` Level I '' divides North America into 15 broad ecoregions . `` Level II '' subdivides the continent into 52 smaller ecoregions . `` Level III '' subdivides those regions again into 182 ecoregions . `` Level IV '' is a further subdivision of Level III ecoregions . Level IV mapping is still underway but is complete across most of the United States . For an example of Level IV data , see List of ecoregions in Oregon and the associated articles . |
1430 | 2006_European_heat_wave | Seventeen of the 18 warmest years have occurred since 2000. | 2006 European heat wave The 2006 European heat wave was a period of exceptionally hot weather that arrived at the end of June 2006 in certain European countries . The United Kingdom , France , Belgium , the Netherlands , Luxembourg , Italy , Poland , the Czech Republic , Hungary , Germany and western parts of Russia were most affected . Several records were broken . In the Netherlands , Belgium , Germany , Ireland and the United Kingdom , July 2006 was the warmest month since official measurements began . |
1818 | Hydrofluorocarbon | HFCs (hydrofluorocarbons) are tens of thousands of times more polluting than carbon dioxide. | Hydrofluorocarbon Hydrofluorocarbons ( HFCs ) , organic compounds that contain fluorine and hydrogen atoms , are the most common type of organofluorine compounds . They are commonly used in air conditioning and as refrigerants in place of the older chlorofluorocarbons such as R-12 and hydrochlorofluorocarbons such as R-21 . They do not harm the ozone layer as much as the compounds they replace ; however , they do contribute to global warming . Their atmospheric concentrations and contribution to anthropogenic greenhouse gas emissions are rapidly increasing , causing international concern about their radiative forcing . Fluorocarbons with few C -- F bonds behave similarly to the parent hydrocarbons , but their reactivity can be altered significantly . For example , both uracil and 5-fluorouracil are colourless , high-melting crystalline solids , but the latter is a potent anti-cancer drug . The use of the C-F bond in pharmaceuticals is predicated on this altered reactivity . Several drugs and agrochemicals contain only one fluorine center or one trifluoromethyl group . Unlike other greenhouse gases in the Paris Agreement , hydrofluorocarbons have other international negotiations . In September 2016 , the so-called New York Declaration urged a global reduction in the use of HFCs . On 15 October 2016 , due to these chemicals ' contribution to climate change , negotiators from 197 nations meeting at the summit of the United Nations Environment Programme in Kigali , Rwanda reached a legally-binding accord to phase out hydrofluorocarbons ( HFCs ) in an amendment to the Montreal Protocol . |
1084 | Non-renewable_resource | [Jonathan Overpeck:] 'No doubt about it anymore — humans, mainly by burning fossil fuels, are cooking the planet,' Overpeck said. | Non-renewable resource A non-renewable resource ( also called a finite resource ) is a resource that does not renew itself at a sufficient rate for sustainable economic extraction in meaningful human time-frames . An example is carbon-based , organically-derived fuel . The original organic material , with the aid of heat and pressure , becomes a fuel such as oil or gas . Earth minerals and metal ores , fossil fuels ( coal , petroleum , natural gas ) and groundwater in certain aquifers are all considered non-renewable resources , though individual elements are almost always conserved . In contrast , resources such as timber ( when harvested sustainably ) and wind ( used to power energy conversion systems ) are considered renewable resources , largely because their localized replenishment can occur within time frames meaningful to humans . |
1317 | Global_warming | "…climate change will also reduce the number of cold days and cold spells. | 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 . |
532 | Fossil_fuel_power_station | Never mind that the emissions of carbon dioxide to make and maintain a wind or solar industrial complex are far greater than they will ever save. | Fossil fuel power station A fossil fuel power station is a power station which burns fossil fuel such as coal , natural gas , or petroleum to produce electricity . Central station fossil fuel power plants are designed on a large scale for continuous operation . In many countries , such plants provide most of the electrical energy used . Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy , which then operates an electrical generator . The prime mover may be a steam turbine , a gas turbine or , in small plants , a reciprocating internal combustion engine . All plants use the energy extracted from expanding gas , either steam or combustion gases . Very few MHD generators have been built which directly convert the energy of hot , moving water into electricity . MHD means Magnetohydrodynamics , which is the study of the magnetic properties of electrically conducting fluids . Examples of such magnetofluids include plasmas , liquid metals , salt water and electrolytes . By-products of thermal power plant operation must be considered in their design and operation . Waste heat energy , which remains due to the finite efficiency of the Carnot , Rankine , or Diesel power cycle , is released directly to the atmosphere or river/lake water , or indirectly to the atmosphere using a cooling tower with river or lake water used as a cooling medium . The flue gas from combustion of the fossil fuels is discharged to the air . This gas contains carbon dioxide and water vapor , as well as other substances such as nitrogen oxides ( NOx ) , sulfur oxides ( SOx ) , mercury , traces of other metals , and , for coal-fired plants , fly ash . Solid waste ash from coal-fired boilers must also be removed . Some coal ash can be recycled for building materials . Fossil fueled power stations are major emitters of carbon dioxide ( CO2 ) , a greenhouse gas which according to a consensus opinion of scientific organisations is a contributor to global warming . The results of a recent study show that the net income available to shareholders of large companies could see a significant reduction from the greenhouse gas emissions liability related to only natural disasters in the U.S. from a single coal-fired power plant . However , as of 2015 , no such cases have awarded damages in the U.S. Per unit of electric energy , brown coal emits nearly two times as much CO2 as natural gas , and black coal emits somewhat less than brown . Carbon capture and storage of emissions is not currently available . |
235 | Jupiter | The planet's average ground temperature has risen by around 1.62F (0.9C) | Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System . It is a giant planet with a mass one-thousandth that of the Sun , but two and a half times that of all the other planets in the Solar System combined . Jupiter and Saturn are gas giants ; the other two giant planets , Uranus and Neptune are ice giants . Jupiter has been known to astronomers since antiquity . The Romans named it after their god Jupiter . When viewed from Earth , Jupiter can reach an apparent magnitude of − 2.94 , bright enough for its reflected light to cast shadows , and making it on average the third-brightest object in the night sky after the Moon and Venus . Jupiter is primarily composed of hydrogen with a quarter of its mass being helium , though helium comprises only about a tenth of the number of molecules . It may also have a rocky core of heavier elements , but like the other giant planets , Jupiter lacks a well-defined solid surface . Because of its rapid rotation , the planet 's shape is that of an oblate spheroid ( it has a slight but noticeable bulge around the equator ) . The outer atmosphere is visibly segregated into several bands at different latitudes , resulting in turbulence and storms along their interacting boundaries . A prominent result is the Great Red Spot , a giant storm that is known to have existed since at least the 17th century when it was first seen by telescope . Surrounding Jupiter is a faint planetary ring system and a powerful magnetosphere . Jupiter has at least 67 moons , including the four large Galilean moons discovered by Galileo Galilei in 1610 . Ganymede , the largest of these , has a diameter greater than that of the planet Mercury . Jupiter has been explored on several occasions by robotic spacecraft , most notably during the early Pioneer and Voyager flyby missions and later by the Galileo orbiter . In late February 2007 , Jupiter was visited by the New Horizons probe , which used Jupiter 's gravity to increase its speed and bend its trajectory en route to Pluto . The latest probe to visit the planet is Juno , which entered into orbit around Jupiter on July 4 , 2016 . Future targets for exploration in the Jupiter system include the probable ice-covered liquid ocean of its moon Europa . |
2464 | Intergovernmental_Panel_on_Climate_Change | While natural forcings can account for much of the early 20th Century warming, humans played a role as well. | Intergovernmental Panel on Climate Change The Intergovernmental Panel on Climate Change ( IPCC ) is a scientific and intergovernmental body under the auspices of the United Nations , set up at the request of member governments , dedicated to the task of providing the world with an objective , scientific view of climate change and its political and economic impacts . It was first established in 1988 by two United Nations organizations , the World Meteorological Organization ( WMO ) and the United Nations Environment Programme ( UNEP ) , and later endorsed by the United Nations General Assembly through Resolution 43/53 . Membership of the IPCC is open to all members of the WMO and UNEP . The IPCC produces reports that support the United Nations Framework Convention on Climate Change ( UNFCCC ) , which is the main international treaty on climate change . The ultimate objective of the UNFCCC is to `` stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic -LSB- i.e. , human-induced -RSB- interference with the climate system '' . IPCC reports cover `` the scientific , technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change , its potential impacts and options for adaptation and mitigation . '' The IPCC does not carry out its own original research , nor does it do the work of monitoring climate or related phenomena itself . The IPCC bases its assessment on the published literature , which includes peer-reviewed and non-peer-reviewed sources . Thousands of scientists and other experts contribute ( on a voluntary basis , without payment from the IPCC ) to writing and reviewing reports , which are then reviewed by governments . IPCC reports contain a `` Summary for Policymakers '' , which is subject to line-by-line approval by delegates from all participating governments . Typically this involves the governments of more than 120 countries . The IPCC provides an internationally accepted authority on climate change , producing reports which have the agreement of leading climate scientists and the consensus of participating governments . The 2007 Nobel Peace Prize was shared , in equal parts , between the IPCC and Al Gore . |
2571 | Google_Scholar | The error was incorrect citation, failing to mention the peer-reviewed papers where the data came from. | Google Scholar Google Scholar is a freely accessible web search engine that indexes the full text or metadata of scholarly literature across an array of publishing formats and disciplines . Released in beta in November 2004 , the Google Scholar index includes most peer-reviewed online academic journals and books , conference papers , theses and dissertations , preprints , abstracts , technical reports , and other scholarly literature , including court opinions and patents . While Google does not publish the size of Google Scholar 's database , third-party researchers estimated it to contain roughly 160 million documents as of May 2014 and an earlier statistical estimate published in PLOS ONE using a Mark and recapture method estimated approximately 80-90 % coverage of all articles published in English with an estimate of 100 million . This estimate also determined how many documents were freely available on the web . Google Scholar is similar in function to the freely available CiteSeerX and getCITED . It also resembles the subscription-based tools , Elsevier 's Scopus and Thomson Reuters ' Web of Science . |
342 | Attribution_of_recent_climate_change | While members of the media may nod along to such claims [about changes in weather extremes], the evidence paints a different story | Attribution of recent climate change Attribution of recent climate change is the effort to scientifically ascertain mechanisms responsible for recent climate changes on Earth , commonly known as ` global warming ' . The effort has focused on changes observed during the period of instrumental temperature record , when records are most reliable ; particularly in the last 50 years , when human activity has grown fastest and observations of the troposphere have become available . The dominant mechanisms are anthropogenic , i.e. , the result of human activity . They are : increasing atmospheric concentrations of greenhouse gases global changes to land surface , such as deforestation increasing atmospheric concentrations of aerosols . There are also natural mechanisms for variation including climate oscillations , changes in solar activity , and volcanic activity . According to the Intergovernmental Panel on Climate Change ( IPCC ) , it is `` extremely likely '' that human influence was the dominant cause of global warming between 1951 and 2010 . The IPCC defines `` extremely likely '' as indicating a probability of 95 to 100 % , based on an expert assessment of all the available evidence . Multiple lines of evidence support attribution of recent climate change to human activities : A basic physical understanding of the climate system : greenhouse gas concentrations have increased and their warming properties are well-established . Historical estimates of past climate changes suggest that the recent changes in global surface temperature are unusual . Computer-based climate models are unable to replicate the observed warming unless human greenhouse gas emissions are included . Natural forces alone ( such as solar and volcanic activity ) can not explain the observed warming . The IPCC 's attribution of recent global warming to human activities is a view shared by the scientific community , and is also supported by 196 other scientific organizations worldwide ( see also : scientific opinion on climate change ) . |
1183 | Kiribati | "suggest that residents are fleeing atolls swiftly sinking into the sea. | Kiribati Kiribati ( -LSB- ˌkɪrɪˈbæs -RSB- or -LSB- ˌkɪrɪˈbɑːti -RSB- ) , officially the Republic of Kiribati ( Gilbertese : Ribaberiki Kiribati ) , is an island nation in the central Pacific Ocean . The permanent population is just over 100,000 ( 2011 ) , more than half of whom live on Tarawa Atoll . The nation comprises 33 atolls and reef islands and one raised coral island , Banaba . They have a total land area of 800 km2 and are dispersed over 3.5 million square kilometres ( 1,351,000 square miles ) . Their spread straddles the equator and the 180th meridian , although the International Date Line is indented to bring the Line Islands in the same day as the Kiribati Islands . The International Date Line circumscribes Kiribati by swinging far to the east , almost reaching the 150 ° W meridian . Kiribati 's easternmost islands , the southern Line Islands , south of Hawaii , have the most advanced time on Earth , UTC +14 hours . Kiribati became independent from the United Kingdom in 1979 . The capital and now most populated area , South Tarawa , consists of a number of islets , connected by a series of causeways . These comprise about half the area of Tarawa Atoll . Kiribati is a member of the Commonwealth of Nations , the IMF and the World Bank , and became a full member of the United Nations in 1999 . |
3017 | East_Antarctic_Ice_Sheet | Some of the regions in which GRACE claims ice loss in East Antarctica average colder than -30°C during the summer, and never, ever get above freezing. | East Antarctic Ice Sheet The East Antarctic Ice Sheet ( EAIS ) is one of two large ice sheets in Antarctica , and the largest on the entire planet . The EAIS lies between 45 ° west and 168 ° east longitudinally . The EAIS is considerably larger in area and mass than the West Antarctic Ice Sheet ( WAIS ) . It is separated from the WAIS by the Transantarctic Mountains . The EAIS rests upon a large land mass , contrary to that of the WAIS , which rests mainly on bedrock below sea level . The EAIS is also home to the thickest ice on the frozen white continent , at 15,700 ft ( 4,800 m ) . More well known , however , is that the EAIS is home to the geographic South Pole as well as of the Amundsen-Scott South Pole Station . |
38 | Ice_age | Scientists studying Antarctica sea ice warn a rise in accumulation could spark the next ice age. | 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 . |
449 | Global_warming_controversy | So it's clear now we're not seeing dangerous global warming, and the climate models are wrong. | 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 . |
377 | Atmosphere_of_Venus | If we halve the carbon dioxide content of the atmosphere, all life dies. | Atmosphere of Venus The atmosphere of Venus is the layer of gases surrounding Venus . It is composed primarily of carbon dioxide and is much denser and hotter than that of Earth . The temperature at the surface is 740 K ( 467 ° C , 872 ° F ) , and the pressure is 93 bar ( 9.3 MPa ) , roughly the pressure found 900 m underwater on Earth . The Venusian atmosphere supports opaque clouds made of sulfuric acid , making optical Earth-based and orbital observation of the surface impossible . Information about the topography has been obtained exclusively by radar imaging . Aside from carbon dioxide , the other main component is nitrogen . Other chemical compounds are present only in trace amounts . Mikhail Lomonosov was the first person to hypothesize the existence of an atmosphere on Venus based on his observation of the transit of Venus of 1761 in a small observatory near his house in Saint Petersburg , Russia . Aside from the very surface layers , the atmosphere is in a state of vigorous circulation . The upper layer of troposphere exhibits a phenomenon of super-rotation , in which the atmosphere circles the planet in just four Earth days , much faster than the planet 's sidereal day of 243 days . The winds supporting super-rotation blow at a speed of 100 m/s ( ~ 360 km/h or 220 mph ) or more . Winds move at up to 60 times the speed of the planet 's rotation , while Earth 's fastest winds are only 10 % to 20 % rotation speed . On the other hand , the wind speed becomes increasingly slower as the elevation from the surface decreases , with the breeze barely reaching the speed of 10 km/h ( 2.8 m/s ) on the surface . Near the poles are anticyclonic structures called polar vortices . Each vortex is double-eyed and shows a characteristic S-shaped pattern of clouds . Above there is an intermediate layer of mesosphere which separates the troposphere from the thermosphere . The thermosphere is also characterized by strong circulation , but very different in its nature - the gases heated and partially ionized by sunlight in the sunlit hemisphere migrate to the dark hemisphere where they recombine and downwell . Unlike Earth , Venus lacks a magnetic field . Its ionosphere separates the atmosphere from outer space and the solar wind . This ionised layer excludes the solar magnetic field , giving Venus a distinct magnetic environment . This is considered Venus 's induced magnetosphere . Lighter gases , including water vapour , are continuously blown away by the solar wind through the induced magnetotail . It is speculated that the atmosphere of Venus up to around 4 billion years ago was more like that of the Earth with liquid water on the surface . A runaway greenhouse effect may have been caused by the evaporation of the surface water and subsequent rise of the levels of other greenhouse gases . Despite the harsh conditions on the surface , the atmospheric pressure and temperature at about 50 km to 65 km above the surface of the planet is nearly the same as that of the Earth , making its upper atmosphere the most Earth-like area in the Solar System , even more so than the surface of Mars . Due to the similarity in pressure and temperature and the fact that breathable air ( 21 % oxygen , 78 % nitrogen ) is a lifting gas on Venus in the same way that helium is a lifting gas on Earth , the upper atmosphere has been proposed as a location for both exploration and colonization . On January 29 , 2013 , ESA scientists reported that the ionosphere of the planet Venus streams outwards in a manner similar to `` the ion tail seen streaming from a comet under similar conditions . '' |
770 | Global_warming | [CO2] has increased 43 percent above the pre-industrial level so far | 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 . |
1390 | Temperate_climate | "Lyme Disease is much more common in northern, cooler regions of the United States than in southern, warmer regions. | Temperate climate In geography , temperate or tepid latitudes of Earth lie between the tropics and the polar regions . The temperatures in these regions are generally relatively moderate , rather than extremely hot or cold , and the changes between summer and winter are also usually moderate . |
1588 | Arctic | Melting ice isn't warming the Arctic. | Arctic The Arctic ( -LSB- ˈɑrktɪk -RSB- or -LSB- ˈɑrtɪk -RSB- ) is a polar region located at the northernmost part of Earth . The Arctic consists of the Arctic Ocean , adjacent seas , and parts of Alaska ( United States ) , Canada , Finland , Greenland ( Denmark ) , Iceland , Norway , Russia and Sweden . Land within the Arctic region has seasonally varying snow and ice cover , with predominantly treeless permafrost-containing tundra . Arctic seas contain seasonal sea ice in many places . The Arctic region is a unique area among Earth 's ecosystems . For example , the cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions . In recent years , Arctic sea ice decline has been caused by global warming . Life in the Arctic includes organisms living in the ice , zooplankton and phytoplankton , fish and marine mammals , birds , land animals , plants and human societies . Arctic land is bordered by the subarctic . |
366 | Vietnam_War | Armed conflicts over resources may become a reality, and have the potential to escalate into nuclear war. | Vietnam War The Vietnam War ( Chiến tranh Việt Nam ) , also known as the Second Indochina War , and known in Vietnam as Resistance War Against America ( Kháng chiến chống Mỹ ) or simply the American War , was a war that occurred in Vietnam , Laos , and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975 . It was the second of the Indochina Wars and was officially fought between North Vietnam and the government of South Vietnam . The North Vietnamese army was supported by the Soviet Union , China and other communist allies and the South Vietnamese army was supported by the United States , South Korea , Australia , Thailand and other anti-communist allies . The war is therefore considered a Cold War-era proxy war . The Viet Cong ( also known as the National Liberation Front , or NLF ) , a South Vietnamese communist common front aided by the North , fought a guerrilla war against anti-communist forces in the region , while the People 's Army of Vietnam , also known as the North Vietnamese Army ( NVA ) , engaged in more conventional warfare , at times committing large units to battle . As the war continued , the military actions of the Viet Cong decreased as the role and engagement of the NVA grew . U.S. and South Vietnamese forces relied on air superiority and overwhelming firepower to conduct search and destroy operations , involving ground forces , artillery , and airstrikes . In the course of the war , the U.S. conducted a large-scale strategic bombing campaign against North Vietnam . The North Vietnamese government and the Viet Cong were fighting to reunify Vietnam . They viewed the conflict as a colonial war and a continuation of the First Indochina War against forces from France and later on the United States . The U.S. government viewed its involvement in the war as a way to prevent a communist takeover of South Vietnam . This was part of the domino theory of a wider containment policy , with the stated aim of stopping the spread of communism worldwide . Beginning in 1950 , American military advisors arrived in what was then French Indochina.The Military Assistance Advisory Group , Indochina ( with an authorized strength of 128 men ) was set up in September 1950 with a mission to oversee the use and distribution of US military equipment by the French and their allies . U.S. involvement escalated in the early 1960s , with troop levels tripling in 1961 and again in 1962 . U.S. involvement escalated further following the 1964 Gulf of Tonkin incident , in which a U.S. destroyer clashed with North Vietnamese fast attack craft , which was followed by the Gulf of Tonkin Resolution , which gave the U.S. president authorization to increase U.S. military presence . Regular U.S. combat units were deployed beginning in 1965 . Operations crossed international borders : bordering areas of Laos and Cambodia were heavily bombed by U.S. forces as American involvement in the war peaked in 1968 , the same year that the communist side launched the Tet Offensive . The Tet Offensive failed in its goal of overthrowing the South Vietnamese government , but became the turning point in the war , as it persuaded a large segment of the U.S. population that its government 's claims of progress toward winning the war were illusory despite many years of massive U.S. military aid to South Vietnam . Gradual withdrawal of U.S. ground forces began as part of `` Vietnamization '' , which aimed to end American involvement in the war while transferring the task of fighting the communists to the South Vietnamese themselves . Despite the Paris Peace Accord , which was signed by all parties in January 1973 , the fighting continued . In the U.S. and the Western world , a large anti-Vietnam War movement developed as part of a larger counterculture . The war changed the dynamics between the Eastern and Western Blocs , and altered North -- South relations . Direct U.S. military involvement ended on 15 August 1973 . The capture of Saigon by the North Vietnamese Army in April 1975 marked the end of the war , and North and South Vietnam were reunified the following year . The war exacted a huge human cost in terms of fatalities ( see Vietnam War casualties ) . Estimates of the number of Vietnamese soldiers and civilians killed vary from 966,000 to 3.8 million . Some 240,000 -- 300,000 Cambodians , 20,000 -- 62,000 Laotians , and 58,220 U.S. service members also died in the conflict , and a further 1,626 remain missing in action . |
2329 | Northwest_Passage | We know the Northwest Passage had been open before." | Northwest Passage The Northwest Passage is a sea route connecting the northern Atlantic and Pacific Oceans through the Arctic Ocean , along the northern coast of North America via waterways through the Canadian Arctic Archipelago . The various islands of the archipelago are separated from one another and from the Canadian mainland by a series of Arctic waterways collectively known as the Northwest Passages or Northwestern Passages . For centuries , European explorers sought a navigable passage as a possible trade route to Asia . An ice-bound northern route was discovered in 1850 by the Irish explorer Robert McClure ; however , it was through a more southerly opening in an area explored by the Scotsman John Rae in 1854 that Norwegian Roald Amundsen made the first complete passage in 1903 -- 1906 . Until 2009 , the Arctic pack ice prevented regular marine shipping throughout most of the year . Arctic sea ice decline has rendered the waterways more navigable . The contested sovereignty claims over the waters may complicate future shipping through the region : the Canadian government considers the Northwestern Passages part of Canadian Internal Waters , but the United States and various European countries maintain they are an international strait and transit passage , allowing free and unencumbered passage . If , as has been claimed , parts of the eastern end of the Passage are barely 15 m deep , the route 's viability as a Euro-Asian shipping route is reduced . However , a Chinese shipping line is planning regular voyages of cargo ships using the passage to the eastern United States and Europe , after a successful passage by Nordic Orion of 73,500 tonnes deadweight tonnage in September 2013 . Fully loaded , Nordic Orion was too large to sail through the Panama Canal . |
1145 | Climate_change_in_the_Arctic | For what appears to be the first time since scientists began keeping track, sea ice in the Arctic and the Antarctic are at record lows this time of year. | 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 . |
1265 | 2007_United_Kingdom_floods | Some, however, bristle at the belief that because floods and storms have always occurred, they should not be linked to climate change" | 2007 United Kingdom floods A series of destructive floods occurred in parts of the United Kingdom during the summer of 2007 . The worst of the flooding occurred across Scotland on 14 June ; East Yorkshire and The Midlands on 15 June ; Yorkshire , The Midlands , Gloucestershire , Herefordshire and Worcestershire on 25 June ; and Gloucestershire , Herefordshire , Worcestershire , Oxfordshire , Berkshire and South Wales on 28 July 2007 . June was one of the wettest months on record in Britain ( see List of weather records ) . Average rainfall across the country was 140 mm ; more than double the June average . Some areas received a month 's worth of precipitation in 24 hours . It was Britain 's wettest May -- July since records began in 1776 . July had unusually unsettled weather and above-average rainfall through the month , peaking on 20 July as an active frontal system dumped more than 120 mm of rain in southern England . Civil and military authorities described the June and July rescue efforts as the biggest in peacetime Britain . The Environment Agency described the July floods as critical and expected them to exceed the 1947 benchmark . |
2048 | Carbon_dioxide | CO2 is a greenhouse gas but is clearly subordinate to water vapour and other more significant factors determining global climate. | 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 . |
556 | Climate_of_Chicago | The April low temperatures here are now about 6 degrees Fahrenheit warmer than they used to be. | Climate of Chicago The climate of Chicago is classified as humid continental ( Köppen Dfa ) , with all four seasons distinctly represented : wet , cool springs ; somewhat hot , and often humid , summers ; pleasantly mild autumns ; and cold winters . Annual precipitation in Chicago is average , and reaches its lowest points in the months of January and February , and peaks in the months of May and June . Chicago 's weather is influenced by the nearby presence of Lake Michigan during all four seasons . |
2071 | Hazard | Carbon pollution is a health hazard. | Hazard A hazard is a situation that poses a level of threat to life , health , property , or environment . Hazards can be dormant or potential , with only a theoretical risk of harm ; however , once a hazard becomes `` active '' , it can create an emergency . A hazardous situation that has come to pass is called an incident . Hazard , consequence and probability interact together to create risk . Identification of hazard risks is the first step in performing a risk assessment . |
1806 | Global_warming | The IPCC 95% confidence that humans are responsible for most of the current global warming is simply a summary of the peer-reviewed scientific research. | 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 . |
2246 | Climate_change_feedback | "His [Dr Spencer's] latest research demonstrates that – in the short term, at any rate – the temperature feedbacks that the IPCC imagines will greatly amplify any initial warming caused by CO2 are net-negative, attenuating the warming they are supposed to enhance. | Climate change feedback Climate change feedback is important in the understanding of global warming because feedback processes may amplify or diminish the effect of each climate forcing , and so play an important part in determining the climate sensitivity and future climate state . Feedback in general is the process in which changing one quantity changes a second quantity , and the change in the second quantity in turn changes the first . Positive feedback amplifies the change in the first quantity while negative feedback reduces it . The term `` forcing '' means a change which may `` push '' the climate system in the direction of warming or cooling . An example of a climate forcing is increased atmospheric concentrations of greenhouse gases . By definition , forcings are external to the climate system while feedbacks are internal ; in essence , feedbacks represent the internal processes of the system . Some feedbacks may act in relative isolation to the rest of the climate system ; others may be tightly coupled ; hence it may be difficult to tell just how much a particular process contributes . Forcings , feedbacks and the dynamics of the climate system determine how much and how fast the climate changes . The main positive feedback in global warming is the tendency of warming to increase the amount of water vapor in the atmosphere , which in turn leads to further warming . The main negative feedback comes from the Stefan -- Boltzmann law , the amount of heat radiated from the Earth into space changes with the fourth power of the temperature of Earth 's surface and atmosphere . Some observed and potential effects of global warming are positive feedbacks , which contribute directly to further global warming . The Intergovernmental Panel on Climate Change 's ( IPCC ) Fourth Assessment Report states that `` Anthropogenic warming could lead to some effects that are abrupt or irreversible , depending upon the rate and magnitude of the climate change . '' |
2214 | Grissom_Air_Reserve_Base | "We found [U.S. weather] stations located next to the exhaust fans of air conditioning units, surrounded by asphalt parking lots and roads, on blistering-hot rooftops, and near sidewalks and buildings that absorb and radiate heat. | Grissom Air Reserve Base Grissom Air Reserve Base is a United States Air Force base , located about 12 mi north of Kokomo in Cass County , Indiana and Miami County , Indiana . The facility was established as Naval Air Station Bunker Hill in 1942 and an active Air Force installation from 1954 to 1994 . Since then it is a joint-use civil airport/military base with the Grissom Aeroplex providing general aviation and charter service . The base is named in memory of astronaut and Indiana native Virgil I. `` Gus '' Grissom , who , along with fellow astronauts Ed White and Roger Chaffee , perished in the Apollo 1 fire at Cape Canaveral Air Force Station Launch Complex 34 in 1967 . |
1069 | Atlantic_Ocean | "There is now less sea ice on Earth than at any time on record. | Atlantic Ocean The Atlantic Ocean is the second largest of the world 's oceans with a total area of about 106,460,000 km2 . It covers approximately 20 percent of the Earth 's surface and about 29 percent of its water surface area . It separates the `` Old World '' from the `` New World '' . The Atlantic Ocean occupies an elongated , S-shaped basin extending longitudinally between Eurasia and Africa to the east , and the Americas to the west . As one component of the interconnected global ocean , it is connected in the north to the Arctic Ocean , to the Pacific Ocean in the southwest , the Indian Ocean in the southeast , and the Southern Ocean in the south ( other definitions describe the Atlantic as extending southward to Antarctica ) . The Equatorial Counter Current subdivides it into the North Atlantic Ocean and South Atlantic Ocean at about 8 ° N. Scientific explorations of the Atlantic include the Challenger expedition , the German Meteor expedition , Columbia University 's Lamont-Doherty Earth Observatory and the United States Navy Hydrographic Office . |
1347 | Global_warming | Scientists say the recent climate agreement negotiated in Paris is not remotely ambitious enough to forestall a significant melting of Greenland and Antarctica, though if fully implemented, it may slow the pace somewhat." | 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 . |
1325 | Hyperthermia | "The Lancet researchers found that about 0.5%—half a percent—of all deaths are associated with heat, not only from acute problems like heat stroke, but also increased mortality from cardiac events and dehydration. | Hyperthermia Hyperthermia is elevated body temperature due to failed thermoregulation that occurs when a body produces or absorbs more heat than it dissipates . Extreme temperature elevation then becomes a medical emergency requiring immediate treatment to prevent disability or death . The most common causes include heat stroke and adverse reactions to drugs . The former is an acute temperature elevation caused by exposure to excessive heat , or combination of heat and humidity , that overwhelms the heat-regulating mechanisms . The latter is a relatively rare side effect of many drugs , particularly those that affect the central nervous system . Malignant hyperthermia is a rare complication of some types of general anesthesia . Hyperthermia differs from fever in that the body 's temperature set point remains unchanged . The opposite is hypothermia , which occurs when the temperature drops below that required to maintain normal metabolism . The term is from Greek ὑπέρ , hyper , meaning `` above '' or `` over '' , and θέρμος , thermos , meaning `` heat '' . |
2838 | Snow | The data is being reported by the University of Illinois's Arctic Climate Research Center, and is derived from satellite observations of the Northern and Southern hemisphere polar regions (Daily Tech). | Snow Snow pertains to frozen crystalline water throughout its life cycle , starting when it precipitates from clouds and accumulates on surfaces , then metamorphoses in place , and ultimately melts , slides or sublimates away . Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air . Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets , which freeze in hexagonal-shaped crystals . Snowflakes take on a variety of shapes , basic among these are platelets , needles , columns and rime . As snow accumulates into a snowpack , it may blow into drifts . Over time , accumulated snow metamorphoses , by sintering , sublimation and freeze-thaw . Where the climate is cold enough for year-to-year accumulation , a glacier may form . Otherwise , snow typically melts seasonally , causing runoff into streams and rivers and recharging groundwater . Major snow-prone areas include the polar regions , the upper half of the Northern Hemisphere and mountainous regions worldwide with sufficient moisture and cold temperatures . In the Southern Hemisphere , snow is confined primarily to mountainous areas , apart from Antarctica . Snow affects such human activities as transportation : creating the need for keeping roadways , wings , and windows clear ; agriculture : providing water to crops and safeguarding livestock ; such sports as skiing , snowboarding , snowmachine travel ; and warfare : impairing target acquisition , degrading the performance of combatants and materiel , and impeding mobility . Snow affects ecosystems , as well , by providing an insulating layer during winter under which plants and animals are able to survive the cold . |
2034 | Effects_of_global_warming | Latest IPCC Reports (AR5) have shown global mean temperature forecasts from the 2005 IPCC report exceeded actual readings. | 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 . |
1790 | Climate_sensitivity | Study finds low probability of both very low and very high climate sensitivities, and its lower estimate (as compared to the IPCC) is based on a new temperature reconstruction of the Last Glacial Maximum that may or may not withstand the test of time. | Climate sensitivity Climate sensitivity is the equilibrium temperature change in response to changes of the radiative forcing . Therefore , climate sensitivity depends on the initial climate state , but potentially can be accurately inferred from precise palaeoclimate data . Slow climate feedbacks , especially changes of ice sheet size and atmospheric CO2 , amplify the total Earth system sensitivity by an amount that depends on the time scale considered . Although climate sensitivity is usually used in the context of radiative forcing by carbon dioxide ( CO2 ) , it is thought of as a general property of the climate system : the change in surface air temperature ( ΔTs ) following a unit change in radiative forcing ( RF ) , and thus is expressed in units of ° C / ( W/m2 ) . For this to be useful , the measure must be independent of the nature of the forcing ( e.g. from greenhouse gases or solar variation ) ; to first order this is indeed found to be so . The climate sensitivity specifically due to is often expressed as the temperature change in ° C associated with a doubling of the concentration of carbon dioxide in Earth 's atmosphere . For coupled atmosphere-ocean global climate models ( e.g. CMIP5 ) the climate sensitivity is an emergent property : it is not a model parameter , but rather a result of a combination of model physics and parameters . By contrast , simpler energy-balance models may have climate sensitivity as an explicit parameter . The terms represented in the equation relate radiative forcing ( RF ) to linear changes in global surface temperature change ( ΔTs ) via the climate sensitivity λ . It is also possible to estimate climate sensitivity from observations ; however , this is difficult due to uncertainties in the forcing and temperature histories . |
952 | Carbon_dioxide_in_Earth's_atmosphere | The Alaskan tundra is warming so quickly it has become a net emitter of carbon dioxide ahead of schedule, a new study finds | Carbon dioxide in Earth's atmosphere Carbon dioxide is an important trace gas in Earth 's atmosphere . Currently it constitutes about 0.041 % ( equal to 410 parts per million ; ppm ) by volume of the atmosphere . Despite its relatively small concentration is a potent greenhouse gas and plays a vital role in regulating Earth 's surface temperature through radiative forcing and the greenhouse effect . Reconstructions show that concentrations of in the atmosphere have varied , ranging from as high as 7,000 ppm during the Cambrian period about 500 million years ago to as low as 180 ppm during the Quaternary glaciation of the last two million years . Carbon dioxide is an integral part of the carbon cycle , a biogeochemical cycle in which carbon is exchanged between the Earth 's oceans , soil , rocks and the biosphere . Plants and other photoautotrophs use solar energy to produce carbohydrate from atmospheric carbon dioxide and water by photosynthesis . Almost all other organisms depend on carbohydrate derived from photosynthesis as their primary source of energy and carbon compounds . The current episode of global warming is attributed to increasing emissions of and other greenhouse gases into Earth 's atmosphere . The global annual mean concentration of in the atmosphere has increased by more than 40 % since the start of the Industrial Revolution , from 280 ppm , the level it had for the last 10,000 years leading up to the mid-18th century , to 399 ppm as of 2015 . The present concentration is the highest in at least the past 800,000 years and likely the highest in the past 20 million years . The increase has been caused by anthropogenic sources , particularly the burning of fossil fuels and deforestation . The daily average concentration of atmospheric CO2 at Mauna Loa Observatory first exceeded 400 ppm on 10 May 2013 . It is currently rising at a rate of approximately 2 ppm/year and accelerating . An estimated 30 -- 40 % of the released by humans into the atmosphere dissolves into oceans , rivers and lakes , which contributes to ocean acidification . |
2205 | Global_warming | "In fact global warming has stopped and a cooling is beginning. | 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 . |
2666 | Snow | Far from contradicting global warming, record snowfall is predicted by climate models and consistent with our expectation of more extreme precipitation events. | Snow Snow pertains to frozen crystalline water throughout its life cycle , starting when it precipitates from clouds and accumulates on surfaces , then metamorphoses in place , and ultimately melts , slides or sublimates away . Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air . Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets , which freeze in hexagonal-shaped crystals . Snowflakes take on a variety of shapes , basic among these are platelets , needles , columns and rime . As snow accumulates into a snowpack , it may blow into drifts . Over time , accumulated snow metamorphoses , by sintering , sublimation and freeze-thaw . Where the climate is cold enough for year-to-year accumulation , a glacier may form . Otherwise , snow typically melts seasonally , causing runoff into streams and rivers and recharging groundwater . Major snow-prone areas include the polar regions , the upper half of the Northern Hemisphere and mountainous regions worldwide with sufficient moisture and cold temperatures . In the Southern Hemisphere , snow is confined primarily to mountainous areas , apart from Antarctica . Snow affects such human activities as transportation : creating the need for keeping roadways , wings , and windows clear ; agriculture : providing water to crops and safeguarding livestock ; such sports as skiing , snowboarding , snowmachine travel ; and warfare : impairing target acquisition , degrading the performance of combatants and materiel , and impeding mobility . Snow affects ecosystems , as well , by providing an insulating layer during winter under which plants and animals are able to survive the cold . |
313 | Global_warming_controversy | Let's find out by comparing the actual temperatures since 1979 with what the 32 families of climate models used in the latest U.N. report on climate science predicted they would be. | 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 . |
2953 | Modular_multiplicative_inverse | In particular, PMOD alters the data from the Nimbus7/ERB record from 1989 to 1991. | Modular multiplicative inverse In mathematics , in particular , the area of number theory , a modular multiplicative inverse of an integer is an integer such that the product is congruent to 1 with respect to the modulus . In the standard notation of modular arithmetic this congruence is written as which is the shorthand way of writing the statement that divides ( evenly ) the quantity , or , put another way , the remainder after dividing by the integer is 1 . If does have an inverse modulo there are an infinite number of solutions of this congruence which form a congruence class with respect to this modulus . Furthermore , any integer that is congruent to ( i.e. , in 's congruence class ) will have any element of 's congruence class as a modular multiplicative inverse . Using the notation of to indicate the congruence class containing , this can be expressed by saying that the modulo multiplicative inverse of the congruence class is the congruence class such that : where the symbol denotes the multiplication of equivalence classes modulo . Written in this way the analogy with the usual concept of a multiplicative inverse in the set of rational or real numbers is clearly represented , replacing the numbers by congruence classes and altering the binary operation appropriately . As with the analogous operation on the real numbers , a fundamental use of this operation is in solving , when possible , linear congruences of the form , Finding modular multiplicative inverses also has practical applications in the field of cryptography , i.e. public-key cryptography and the RSA Algorithm . A benefit for the computer implementation of these applications is that there exists a very fast algorithm ( the extended Euclidean algorithm ) that can be used for the calculation of modular multiplicative inverses . In mathematical theory , assumptions about the properties of binary operators ( for example the associative property and the commutative property ) are often used as axioms in fields of study such as number theory and also two sub-disciplines of abstract algebra , group theory and ring theory . |
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