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1216 | Political_positions_of_Paul_Ryan | …obsessing about climate change is avoiding a frank discussion about the here-and-now problems of budget deficits, the federal debt, school choice, entitlement reform, and so on. | Political positions of Paul Ryan The political positions of Paul Ryan , since 1999 the U.S. Representative from Wisconsin 's 1st congressional district and currently the 54th Speaker of the United States House of Representatives , are conservative and Republican with a focus on fiscal policy . Ryan was Chairman of the House Budget Committee from 2011 to 2015 and of Ways and Means in 2015 . Ryan was the Republican nominee for vice president as the running mate of Mitt Romney in the 2012 presidential election . Ryan supports eliminating the capital gains tax , the corporate income tax , the estate tax , and the Alternative Minimum Tax . In 1999 Ryan supported the Gramm -- Leach -- Bliley Act , which repealed some financial regulation of banks from the Glass -- Steagall Act of 1933 . During the economic recovery from the Great Recession of the late 2000s , Ryan supported the Troubled Asset Relief Program ( TARP ) , which authorized the Treasury to purchase toxic assets from banks and other financial institutions , and the auto industry bailout ; Ryan opposed the Credit CARD Act of 2009 , which expanded consumer protections regarding credit card plans , and the Dodd -- Frank Wall Street Reform and Consumer Protection Act , which strengthened financial regulation . Ryan believes federal poverty reduction programs are ineffective and supports cuts to welfare , child care , Pell Grants , food stamps , and other federal assistance programs . Ryan supports the privatization of social security and Medicare and block granting Medicaid to the states . Ryan supported the Medicare Part D prescription drug benefit , and opposes the Patient Protection and Affordable Care Act ( ACA ) , also known as `` Obamacare '' , and supports its repeal . Ryan is pro-life and opposes abortion rights . Ryan opposed the Lilly Ledbetter Fair Pay Act of 2009 , which bolstered women 's rights to equal pay for equal work . Ryan supports civil unions and opposes same-sex marriage . Ryan supports school vouchers , and supported the No Child Left Behind Act in 2001 and its repeal in 2015 . Ryan is unsure , and believes climate scientists are unsure , of the impact of human activity on climate change . Ryan supports tax incentives for the petroleum industry and opposes them for renewable energy . Ryan supports gun rights and opposes stricter gun control . Ryan supported the wars in Iraq and Afghanistan . |
1761 | Greenhouse_gas | Multiple lines of evidence make it very clear that the rise in atmospheric CO2 is due to human emissions. | 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 . |
983 | Effects_of_global_warming | 'The dry periods are drier and the wet periods are wetter,' said Jeffrey Mount, a water expert and senior fellow at the Public Policy Institute of California. | 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 . |
997 | Global_cooling | Ever since 2012, scientists have been debating a complex and frankly explosive idea about how a warming planet will alter our weather — one that, if it's correct, would have profound implications across the Northern Hemisphere and especially in its middle latitudes | Global cooling Global cooling was a conjecture during the 1970s of imminent cooling of the Earth 's surface and atmosphere culminating in a period of extensive glaciation . This hypothesis had little support in the scientific community , but gained temporary popular attention due to a combination of a slight downward trend of temperatures from the 1940s to the early 1970s and press reports that did not accurately reflect the full scope of the scientific climate literature , which showed a larger and faster-growing body of literature projecting future warming due to greenhouse gas emissions . The current scientific opinion on climate change is that the Earth has not durably cooled , but underwent global warming throughout the 20th century . |
1609 | Retreat_of_glaciers_since_1850 | Greenland has only lost a tiny fraction of its ice mass. | 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 . |
2564 | Sea_level_rise | This small warming is likely a result of the natural alterations in global ocean currents which are driven by ocean salinity variations. | 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 . |
1604 | Greenhouse_gas | CO2 increase is natural, not human-caused. | 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 . |
332 | Earth_shelter | Shelters in poorer countries are not repainted as often, and darker stations absorb more of the sun's energy. | Earth shelter An earth shelter is a structure (usually a house) with earth (soil) against the walls, on the roof, or that is entirely buried underground. Earth acts as thermal mass, making it easier to maintain a steady indoor air temperature and therefore reduces energy costs for heating or cooling. Earth sheltering became relatively popular after the mid 1970s, especially among environmentalists. However, the practice has been around for nearly as long as humans have been constructing their own shelters. |
74 | Global_warming_controversy | The models predicted about three times the amount of warming in the world we've seen since [1988]. | 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 . |
2488 | Global_warming | However, it is unable to explain the long term warming trend over the past few decades. | 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 . |
2130 | Proxy_(climate) | Plant stomata show higher and more variable CO2 levels | Proxy (climate) In the study of past climates ( `` paleoclimatology '' ) , climate proxies are preserved physical characteristics of the past that stand in for direct meteorological measurements and enable scientists to reconstruct the climatic conditions over a longer fraction of the Earth 's history . Reliable global records of climate only began in the 1880s , and proxies provide the only means for scientists to determine climatic patterns before record-keeping began . Examples of proxies include ice cores , tree rings , sub-fossil pollen , boreholes , corals , lake and ocean sediments , and carbonate speleothems . The character of deposition or rate of growth of the proxies ' material has been influenced by the climatic conditions of the time in which they were laid down or grew . Chemical traces produced by climatic changes , such as quantities of particular isotopes , can be recovered from proxies . Some proxies , such as gas bubbles trapped in ice , enable traces of the ancient atmosphere to be recovered and measured directly to provide a history of fluctuations in the composition of the Earth 's atmosphere . To produce the most precise results , systematic cross-verification between proxy indicators is necessary for accuracy in readings and record-keeping . Proxies can be combined to produce temperature reconstructions longer than the instrumental temperature record and can inform discussions of global warming . The distribution of proxy records , just like the instrumental record , is not at all uniform , with more records in the northern hemisphere . |
1055 | Global_warming | They do not make a definitive attribution statement, but the data are consistent with and strongly suggestive of human-driven warming as a root cause of the oxygen decline.'" | 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 . |
2034 | Kyoto_Protocol | Latest IPCC Reports (AR5) have shown global mean temperature forecasts from the 2005 IPCC report exceeded actual readings. | Kyoto Protocol The Kyoto Protocol is an international treaty which extends the 1992 United Nations Framework Convention on Climate Change ( UNFCCC ) that commits State Parties to reduce greenhouse gas emissions , based on the fact that ( a ) global warming exists and ( b ) human-made CO2 emissions have caused it . The Kyoto Protocol was adopted in Kyoto , Japan , on 11 December 1997 and entered into force on 16 February 2005 . There are currently 192 parties ( Canada withdrew effective December 2012 ) to the Protocol . The Kyoto Protocol implemented the objective of the UNFCCC to fight global warming by reducing greenhouse gas concentrations in the atmosphere to `` a level that would prevent dangerous anthropogenic interference with the climate system '' ( Art. 2 ) . The Protocol is based on the principle of common but differentiated responsibilities : it puts the obligation to reduce current emissions on developed countries on the basis that they are historically responsible for the current levels of greenhouse gases in the atmosphere . The Protocol 's first commitment period started in 2008 and ended in 2012 . A second commitment period was agreed on in 2012 , known as the Doha Amendment to the protocol , in which 37 countries have binding targets : Australia , the European Union ( and its 28 member states ) , Belarus , Iceland , Kazakhstan , Liechtenstein , Norway , Switzerland , and Ukraine . Belarus , Kazakhstan and Ukraine have stated that they may withdraw from the Protocol or not put into legal force the Amendment with second round targets . Japan , New Zealand and Russia have participated in Kyoto 's first-round but have not taken on new targets in the second commitment period . Other developed countries without second-round targets are Canada ( which withdrew from the Kyoto Protocol in 2012 ) and the United States ( which has not ratified the Protocol ) . As of July 2016 , 66 states have accepted the Doha Amendment , while entry into force requires the acceptances of 144 states . Of the 37 countries with binding commitments , 7 have ratified . Negotiations were held in the framework of the yearly UNFCCC Climate Change Conferences on measures to be taken after the second commitment period ends in 2020 . This resulted in the 2015 adoption of the Paris Agreement , which is a separate instrument under the UNFCCC rather than an amendment of the Kyoto protocol . |
2977 | Troposphere | According to the study, as carbon levels have risen, the cold air at high altitudes over the tropics has actually grown colder. | Troposphere The troposphere is the lowest portion of Earth 's atmosphere , and is also where nearly all weather takes place . It contains approximately 75 % of the atmosphere 's mass and 99 % of the total mass of water vapor and aerosols . The average depths of the troposphere are 20 km in the tropics , 17 km in the mid latitudes , and 7 km in the polar regions in winter . The lowest part of the troposphere , where friction with the Earth 's surface influences air flow , is the planetary boundary layer . This layer is typically a few hundred meters to 2 km deep depending on the landform and time of day . Atop the troposphere is the tropopause , which is the border between the troposphere and stratosphere . The tropopause is an inversion layer , where the air temperature ceases to decrease with height and remains constant through its thickness . The word troposphere derives from the for `` turn , turn toward , trope '' and '' - sphere '' ( as in , the Earth ) , reflecting the fact that rotational turbulent mixing plays an important role in the troposphere 's structure and behaviour . Most of the phenomena associated with day-to-day weather occur in the troposphere . |
2326 | Northwest_Passage | "In 2007, the Northern Hemisphere reached a record low in ice coverage and the Northwest Passage was opened. | 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 . |
2702 | Climate_change_mitigation | While it's true that any single country's CO2 emissions reductions will make little difference, only if every nation agrees to limit CO2 emissions can we achieve significant cuts on a global scale. | Climate change mitigation Climate change mitigation consists of actions to limit the magnitude or rate of long-term climate change . Climate change mitigation generally involves reductions in human ( anthropogenic ) emissions of greenhouse gases ( GHGs ) . Mitigation may also be achieved by increasing the capacity of carbon sinks , e.g. , through reforestation . Mitigation policies can substantially reduce the risks associated with human-induced global warming . According to the IPCC 's 2014 assessment report , `` Mitigation is a public good ; climate change is a case of the ` tragedy of the commons . Effective climate change mitigation will not be achieved if each agent ( individual , institution or country ) acts independently in its own selfish interest ( see international cooperation and emissions trading ) , suggesting the need for collective action . Some adaptation actions , on the other hand , have characteristics of a private good as benefits of actions may accrue more directly to the individuals , regions , or countries that undertake them , at least in the short term . Nevertheless , financing such adaptive activities remains an issue , particularly for poor individuals and countries . '' Examples of mitigation include phasing out fossil fuels by switching to low-carbon energy sources , such as renewable and nuclear energy , and expanding forests and other `` sinks '' to remove greater amounts of carbon dioxide from the atmosphere . Energy efficiency may also play a role , for example , through improving the insulation of buildings . Another approach to climate change mitigation is climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) . The ultimate objective of the UNFCCC is to stabilize atmospheric concentrations of GHGs at a level that would prevent dangerous human interference of the climate system . Scientific analysis can provide information on the impacts of climate change , but deciding which impacts are dangerous requires value judgments . In 2010 , Parties to the UNFCCC agreed that future global warming should be limited to below 2.0 ° C ( 3.6 ° F ) relative to the pre-industrial level . With the Paris Agreement of 2015 this was confirmed , but was revised with a new target laying down `` parties will do the best '' to achieve warming below 1.5 ° C . The current trajectory of global greenhouse gas emissions does not appear to be consistent with limiting global warming to below 1.5 or 2 ° C . Other mitigation policies have been proposed , some of which are more stringent or modest than the 2 ° C limit . |
3130 | Earth | "There are other possible causes for climate change which could be associated with solar activity or related to variations in the temperature of the liquid core of the Earth, which is about 5,400 degrees Celsius. | 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 . |
530 | South_Australia | South Australia is winning: it has the most unreliable grid in the world outside Africa and the most expensive electricity. | South Australia South Australia ( abbreviated as SA ) is a state in the southern central part of Australia . It covers some of the most arid parts of the country . With a total land area of 983482 km2 , it is the fourth-largest of Australia 's states and territories . It has a total of 1.7 million people , and its population is the most highly centralised of any state in Australia , with more than 75 percent of South Australians living in the capital , Adelaide , or its environs . Other population centres in the state are relatively small . South Australia shares borders with all of the other mainland states , and with the Northern Territory ; it is bordered to the west by Western Australia , to the north by the Northern Territory , to the north-east by Queensland , to the east by New South Wales , to the south-east by Victoria , and to the south by the Great Australian Bight . The state comprises less than 8 percent of the Australian population and ranks fifth in population among the six states and two territories . The majority of its people reside in Adelaide . Most of the remainder are settled in fertile areas along the south-eastern coast and River Murray . The state 's colonial origins are unique in Australia as a freely settled , planned British province , rather than as a convict settlement . Official settlement began on 28 December 1836 , when the colony was proclaimed at the Old Gum Tree by Governor John Hindmarsh . As with the rest of the continent , the region had been long occupied by Aboriginal peoples , who were organised into numerous tribes and languages . The first British settlement to be established was Kingscote , Kangaroo Island , on 26 July 1836 , five months before Adelaide was founded . The guiding principle behind settlement was that of systematic colonisation , a theory espoused by Edward Gibbon Wakefield that was later employed by the New Zealand Company . The goal was to establish the province as a centre of civilisation for free immigrants , promising civil liberties and religious tolerance . Although its history is marked by economic hardship , South Australia has remained politically innovative and culturally vibrant . Today , it is known for its fine wine and numerous cultural festivals . The state 's economy is dominated by the agricultural , manufacturing and mining industries . The state has an increasingly significant finance sector as well . |
1638 | Intergovernmental_Panel_on_Climate_Change | Worry about global warming impacts in the next 100 years, not an ice age in over 10,000 years. | 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 . |
2193 | Global_warming | In the last 35 years of global warming, the sun has shown a slight cooling trend. | 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 . |
220 | Houston | Hurricane Harvey gave Houston and the surrounding region a $125 billion lesson about the costs of misjudging the potential for floods | Houston Houston ( -LSB- ˈhjuːstən -RSB- ) is the most populous city in the state of Texas and the fourth-most populous city in the United States . With a census-estimated 2014 population of 2.239 million within an area of 667 sqmi , it is also the largest city in the southern United States and the seat of Harris County . Located in Southeast Texas near the Gulf of Mexico , it is the principal city of the Greater Houston metro area , which is the fifth-most populated MSA in the United States . Houston was founded on August 28 , 1836 , near the banks of Buffalo Bayou ( now known as Allen 's Landing ) and incorporated as a city on June 5 , 1837 . The city was named after former General Sam Houston , who was president of the Republic of Texas and had commanded and won at the Battle of San Jacinto 25 mi east of where the city was established . The burgeoning port and railroad industry , combined with oil discovery in 1901 , has induced continual surges in the city 's population . In the mid-20th century , Houston became the home of the Texas Medical Center -- the world 's largest concentration of healthcare and research institutions -- and NASA 's Johnson Space Center , where the Mission Control Center is located . Houston 's economy has a broad industrial base in energy , manufacturing , aeronautics , and transportation . Leading in health care sectors and building oilfield equipment , outside of New York City , Houston has more Fortune 500 headquarters than any other U.S. municipality within its city limits . The Port of Houston ranks first in the United States in international waterborne tonnage handled and second in total cargo tonnage handled . Nicknamed the `` Space City '' , Houston is a global city , with strengths in business , international trade , entertainment , culture , media , fashion , science , sports , technology , education , medicine , and research . The city has a population from various ethnic and religious backgrounds and a large and growing international community . Houston is the most diverse city in Texas and has been described as the most racially and ethnically diverse major metropolis in the U.S. . It is home to many cultural institutions and exhibits , which attract more than 7 million visitors a year to the Museum District . Houston has an active visual and performing arts scene in the Theater District and offers year-round resident companies in all major performing arts . |
1127 | El_Niño | This means it is possible that by some yardsticks, 2016 will be declared as hot as 2015 or even slightly hotter – because El Nino did not vanish until the middle of the year. | El Niño El Niño -LSB- ɛl_ˈniːnjoʊ -RSB- ( -LSB- el ˈniɲo -RSB- ) is the warm phase of the El Niño Southern Oscillation ( commonly called ENSO ) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific ( between approximately the International Date Line and 120 ° W ) , including off the Pacific coast of South America . El Niño Southern Oscillation refers to the cycle of warm and cold temperatures , as measured by sea surface temperature , SST , of the tropical central and eastern Pacific Ocean . El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific . The cool phase of ENSO is called `` La Niña '' with SST in the eastern Pacific below average and air pressures high in the eastern and low in western Pacific . The ENSO cycle , both El Niño and La Niña , cause global changes of both temperatures and rainfall . Developing countries that are dependent upon agriculture and fishing , particularly those bordering the Pacific Ocean , are usually most affected . In American Spanish , the capitalized term `` El Niño '' refers to `` the little boy '' , so named because the pool of warm water in the Pacific near South America is often at its warmest around Christmas . The original name , `` El Niño de Navidad '' , traces its origin centuries back to Peruvian fisherman , who named the weather phenomenon in reference to the newborn Christ . `` La Niña '' , chosen as the ` opposite ' of El Niño , literally translates to `` the little girl '' . |
939 | Sea_level_rise | "Recent computer forecasts suggest that if greenhouse gas emissions continue at a high level, parts of Antarctica could break up rapidly, causing the ocean to rise six feet or more by the end of this 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 . |
1075 | Sea_ice | "At the bottom of the world, sea ice is also at all-time record low levels around Antarctica, the data center said. | Sea ice Sea ice arises as seawater freezes . Because ice is less dense than water , it floats on the ocean 's surface ( as does fresh water ice , which has an even lower density ) . Sea ice covers about 7 % of the Earth 's surface and about 12 % of the world 's oceans . Much of the world 's sea ice is enclosed within the polar ice packs in the Earth 's polar regions : the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean . Polar packs undergo a significant yearly cycling in surface extent , a natural process upon which depends the Arctic ecology , including the ocean 's ecosystems . Due to the action of winds , currents and temperature fluctuations , sea ice is very dynamic , leading to a wide variety of ice types and features . Sea ice may be contrasted with icebergs , which are chunks of ice shelves or glaciers that calve into the ocean . Depending on location , sea ice expanses may also incorporate icebergs . |
1435 | Sea_level_rise | An area of coastal ecosystems larger than New York City is destroyed every year, removing an important buffer from extreme weather for coastal communities and releasing carbon dioxide into the atmosphere. | 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 . |
1397 | Climate_change_denial | alarmists here are taking overwhelmingly good news about global warming improving plant health and making it seem like this good news is actually bad news because healthier plants mean more pollen. | Climate change denial Climate change denial , or global warming denial , is part of the global warming controversy . It involves denial , dismissal , unwarranted doubt or contrarian views which strongly depart from the scientific opinion on climate change , including the extent to which it is caused by humans , its impacts on nature and human society , or the potential of adaptation to global warming by human actions . Some deniers do endorse the term , but others often prefer the term climate change skepticism , although this is a misnomer for those who deny anthropogenic global warming . In effect , the two terms form a continuous , overlapping range of views , and generally have the same characteristics : both reject , to a greater or lesser extent , mainstream scientific opinion on climate change . Climate change denial can also be implicit , when individuals or social groups accept the science but fail to come to terms with it or to translate their acceptance into action . Several social science studies have analyzed these positions as forms of denialism . Campaigning to undermine public trust in climate science has been described as a `` denial machine '' of industrial , political and ideological interests , supported by conservative media and skeptical bloggers in manufacturing uncertainty about global warming . In the public debate , phrases such as climate skepticism have frequently been used with the same meaning as climate denialism . The labels are contested : those actively challenging climate science commonly describe themselves as `` skeptics '' , but many do not comply with common standards of scientific skepticism and , regardless of evidence , persistently deny the validity of human caused global warming . Although scientific opinion on climate change is that human activity is extremely likely to be the primary driver of climate change , the politics of global warming have been affected by climate change denial , hindering efforts to prevent climate change and adapt to the warming climate . Those promoting denial commonly use rhetorical tactics to give the appearance of a scientific controversy where there is none . Of the world 's countries , the climate change denial industry is most powerful in the United States . Since January 2015 , the United States Senate Committee on Environment and Public Works has been chaired by oil lobbyist and climate change denier Jim Inhofe . Inhofe is notorious for having called climate change `` the greatest hoax ever perpetrated against the American people '' and for having claimed to have debunked the alleged hoax in February 2015 when he brought a snowball with him in the Senate chamber and tossed it across the floor . Organised campaigning to undermine public trust in climate science is associated with conservative economic policies and backed by industrial interests opposed to the regulation of emissions . Climate change denial has been associated with the fossil fuels lobby , the Koch brothers , industry advocates and libertarian think tanks , often in the United States . More than 90 % of papers sceptical on climate change originate from right-wing think tanks . The total annual income of these climate change counter-movement-organizations is roughly $ 900 million . Between 2002 and 2010 , nearly $ 120 million ( # 77 million ) was anonymously donated via the Donors Trust and Donors Capital Fund to more than 100 organisations seeking to undermine the public perception of the science on climate change . In 2013 the Center for Media and Democracy reported that the State Policy Network ( SPN ) , an umbrella group of 64 U.S. think tanks , had been lobbying on behalf of major corporations and conservative donors to oppose climate change regulation . Since the late 1970s , oil companies have published research broadly in line with the standard views on global warming . Despite this , oil companies organized a climate change denial campaign to disseminate public disinformation for several decades , a strategy that has been compared to the organized denial of the hazards of tobacco smoking by tobacco companies . |
2552 | Triassic | The geologic record provides us with abundant evidence for such perpetual natural climate variability, from icecaps reaching almost to the equator to none at all, even at the poles. | Triassic The Triassic ( -LSB- prontraɪˈæsɪk -RSB- ) is a geologic period and system which spans 50.9 million years from the end of the Permian Period million years ago ( Mya ) , to the beginning of the Jurassic Period Mya . The Triassic is the first period of the Mesozoic Era . Both the start and end of the period are marked by major extinction events . The Triassic began in the wake of the Permian -- Triassic extinction event , which left the earth 's biosphere impoverished ; it would take well into the middle of this period for life to recover its former diversity . Therapsids and archosaurs were the chief terrestrial vertebrates during this time . A specialized subgroup of archosaurs , called dinosaurs , first appeared in the Late Triassic but did not become dominant until the succeeding Jurassic Period . The first true mammals , themselves a specialized subgroup of Therapsids , also evolved during this period , as well as the first flying vertebrates , the pterosaurs , who like the dinosaurs were a specialized subgroup of archosaurs . The vast supercontinent of Pangaea existed until the mid-Triassic , after which it began to gradually rift into two separate landmasses , Laurasia to the north and Gondwana to the south . The global climate during the Triassic was mostly hot and dry , with deserts spanning much of Pangaea 's interior . However , the climate shifted and became more humid as Pangaea began to drift apart . The end of the period was marked by yet another major mass extinction , the Triassic-Jurassic extinction event , that wiped out many groups and allowed dinosaurs to assume dominance in the Jurassic . The Triassic was named in 1834 by Friedrich von Alberti , after the three distinct rock layers ( tri meaning `` three '' ) that are found throughout Germany and northwestern Europe -- red beds , capped by marine limestone , followed by a series of terrestrial mud - and sandstones -- called the `` Trias '' . |
2763 | Little_Ice_Age | The long term trend from albedo is of cooling. | Little Ice Age The Little Ice Age ( LIA ) was a period of cooling that occurred after the Medieval Warm Period . Although it was not a true ice age , the term was introduced into scientific literature by François E. Matthes in 1939 . It has been conventionally defined as a period extending from the 16th to the 19th centuries , but some experts prefer an alternative timespan from about 1300 to about 1850 . Climatologists and historians working with local records no longer expect to agree on either the start or end dates of the period , which varied according to local conditions . The NASA Earth Observatory notes three particularly cold intervals : one beginning about 1650 , another about 1770 , and the last in 1850 , all separated by intervals of slight warming . The Intergovernmental Panel on Climate Change Third Assessment Report considered the timing and areas affected by the Little Ice Age suggested largely-independent regional climate changes rather than a globally-synchronous increased glaciation . At most , there was modest cooling of the Northern Hemisphere during the period . Several causes have been proposed : cyclical lows in solar radiation , heightened volcanic activity , changes in the ocean circulation , variations in Earth 's orbit and axial tilt ( orbital forcing ) , inherent variability in global climate , and decreases in the human population . |
1271 | Ice_sheet | Greenland ice sheet … would balloon sea levels by around 7m should it disintegrate | Ice sheet An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50000 km2 , thus also known as continental glacier . The only current ice sheets are in Antarctica and Greenland ; during the last glacial period at Last Glacial Maximum ( LGM ) the Laurentide ice sheet covered much of North America , the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South America . Ice sheets are bigger than ice shelves or alpine glaciers . Masses of ice covering less than 50,000 km2 are termed an ice cap . An ice cap will typically feed a series of glaciers around its periphery . Although the surface is cold , the base of an ice sheet is generally warmer due to geothermal heat . In places , melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly . This process produces fast-flowing channels in the ice sheet -- these are ice streams . The present-day polar ice sheets are relatively young in geological terms . The Antarctic Ice Sheet first formed as a small ice cap ( maybe several ) in the early Oligocene , but retreating and advancing many times until the Pliocene , when it came to occupy almost all of Antarctica . The Greenland ice sheet did not develop at all until the late Pliocene , but apparently developed very rapidly with the first continental glaciation . This had the unusual effect of allowing fossils of plants that once grew on present-day Greenland to be much better preserved than with the slowly forming Antarctic ice sheet . |
609 | Post-glacial_rebound | That's because as Antarctica's mass shrinks, the ice sheet's gravitational pull on the ocean relaxes somewhat, and the seas travel back across the globe to pile up far away — with U.S. coasts being one prime destination." | Post-glacial rebound Post-glacial rebound ( also called either isostatic rebound or crustal rebound ) is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period , through a process known as isostatic depression . Post-glacial rebound and isostatic depression are different parts of a process known as either glacial isostasy , glacial isostatic adjustment , or glacioisostasy . Glacioisostasy is the solid Earth deformation associated with changes in ice mass distribution . The most obvious and direct effects of post-glacial rebound are readily apparent in parts of Northern Eurasia , Northern America , Patagonia , and Antarctica . However , through processes known as ocean siphoning and continental levering , the effects of post-glacial rebound on sea level are felt globally far from the locations of current and former ice sheets . |
2378 | Mitigation_(law) | The costs of inaction far outweigh the costs of mitigation. | Mitigation (law) Mitigation in law is the principle that a party who has suffered loss ( from a tort or breach of contract ) has to take reasonable action to minimize the amount of the loss suffered . As stated by the Canadian Federal Court of Appeal in Redpath Industries Ltd. v.Cisco ( The ) , `` It is well established that a party who suffers damages as a result of a breach of contract has a duty to mitigate those damages , that is to say that the wrongdoer can not be called upon to pay for avoidable losses which would result in an increase in the quantum of damages payable to the injured party . '' The onus on showing a failure to mitigate damages is on the defendant . For example , consider a tenant who signs an agreement to rent a house for a year , but moves out ( and stops paying rent ) after only one month . The landlord may be able to sue the tenant for breach of contract : however the landlord must mitigate damages by making a reasonable attempt to find a replacement tenant for the remainder of the year . The landlord may not simply let the house lie empty for eleven months and then sue the tenant for eleven months ' rent . The actions of the defendant may also result in the mitigation of damages which would otherwise have been due to the successful plaintiff . For example , the Civil Law ( Wrongs ) Act 2002 ( ACT ) provides that mitigation of damages for the publication of defamatory matter may result from any apology made by a defendant and any correction published ( s. 139I ) . The issue of what is reasonable is especially contentious in personal injury cases where the plaintiff refuses medical advice . This can be seen in cases such as Janiak v. Ippolito . The antonym of mitigation is aggravation . |
2712 | Climate_change_in_the_Arctic | The news of expanding Antarctic sea ice stole headlines from global warming alarmists who asserted Arctic sea ice had reached its lowest extent since 1979.' | 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 . |
104 | Carbon_dioxide | Increases in atmospheric CO2 followed increases in temperature. | 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 . |
1986 | Environmental_policy_of_the_Donald_Trump_administration | The Obama administration "has been constrained by the Oil Pollution Act of 1990, which basically gives the responsible party the lead role in trying to not only fix the problem, but contain the problem." | Environmental policy of the Donald Trump administration The environmental policy of the Donald Trump administration represents a shift from the policy priorities and goals of his predecessor , Barack Obama . During the campaign Trump often described environmental regulations as an impediment to business . He promised to roll back many regulations and end a moratorium on the leasing of federal coal reserves . Immediately upon his inauguration , the White House released an `` America First Energy Plan '' , which focused on fossil fuels and did not mention renewable energy . The plan would repeal many Obama policies including the Climate Action Plan and the Waters of the U.S. rule , and limit the Environmental Protection Agency 's mission to protecting air and water quality . Within days of taking office he signed executive orders to approve two controversial pipelines and to require federal review of the Clean Water Rule and the Clean Power Plan . He also invited American manufacturers to suggest what regulations should be eliminated ; industry leaders submitted 168 comments , of which nearly half targeted Environmental Protection Agency rules . In March 2017 he released a proposed 2018 budget which would cut funding for the EPA by 31 % . In May 2017 Congress approved a budget for the balance of the 2017-18 year which cuts the EPA 's funding by 1 % and eliminates no jobs . Trump 's appointments to key agencies dealing in energy and environmental policy reflected his commitment to deregulation , particularly of the fossil fuel industry . Several of his cabinet picks , such as Rick Perry as Secretary of Energy and Scott Pruitt as Administrator of the Environmental Protection Agency , were of people with a history of opposition to the agency they were named to head . |
1474 | Greenhouse_gas | Etna has already put more than 10,000 times the CO2 into the atmosphere than mankind has in our entire time on the Earth. | 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 . |
3004 | Tibetan_calendar | "The solar system oscillates with a 60-year cycle due to the Jupiter/Saturn three-synodic cycle and to a Jupiter/Saturn beat tidal cycle... | Tibetan calendar The Tibetan calendar is a lunisolar calendar , that is , the Tibetan year is composed of either 12 or 13 lunar months , each beginning and ending with a new moon . A thirteenth month is added every two or three years , so that an average Tibetan year is equal to the solar year . The Tibetan New Year celebration is Losar . According to almanacs the year starts with the third Hor month . There were many different traditions in Tibet to fix the beginning of the year . The dates of Mongolian calendar are all the same with it . |
2927 | Climate_sensitivity | CO2 changes are closely related to temperature. | 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 . |
31 | Permian–Triassic_extinction_event | Discovery Of Massive Volcanic CO2 Emissions Discredits Global Warming Theory | Permian–Triassic extinction event The Permian -- Triassic ( P -- Tr or P -- T ) extinction event , colloquially known as the Great Dying , the End-Permian Extinction or the Great Permian Extinction , occurred about 252 Ma ( million years ) ago , forming the boundary between the Permian and Triassic geologic periods , as well as the Paleozoic and Mesozoic eras . It is the Earth 's most severe known extinction event , with up to 96 % of all marine species and 70 % of terrestrial vertebrate species becoming extinct . It is the only known mass extinction of insects . Some 57 % of all families and 83 % of all genera became extinct . Because so much biodiversity was lost , the recovery of life on Earth took significantly longer than after any other extinction event , possibly up to 10 million years . Studies in Bear Lake County near the Idaho city of Paris showed a quick and dynamic rebound in a marine ecosystem , illustrating the remarkable resiliency of life . There is evidence for one to three distinct pulses , or phases , of extinction . Suggested mechanisms for the latter include one or more large meteor impact events , massive volcanism such as that of the Siberian Traps , and the ensuing coal or gas fires and explosions , and a runaway greenhouse effect triggered by sudden release of methane from the sea floor due to methane clathrate dissociation or methane-producing microbes known as methanogens ; possible contributing gradual changes include sea-level change , increasing anoxia , increasing aridity , and a shift in ocean circulation driven by climate change . |
126 | Sea_level_rise | El Niño drove record highs in global temperatures suggesting rise may not be down to man-made emissions. | 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 . |
1544 | Arctic_ice_pack | Arctic icemelt is a natural cycle. | 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 . |
2262 | Proxy_(climate) | Since the hockey stick paper in 1998, there have been a number of proxy studies analysing a variety of different sources including corals, stalagmites, tree rings, boreholes and ice cores. | Proxy (climate) In the study of past climates ( `` paleoclimatology '' ) , climate proxies are preserved physical characteristics of the past that stand in for direct meteorological measurements and enable scientists to reconstruct the climatic conditions over a longer fraction of the Earth 's history . Reliable global records of climate only began in the 1880s , and proxies provide the only means for scientists to determine climatic patterns before record-keeping began . Examples of proxies include ice cores , tree rings , sub-fossil pollen , boreholes , corals , lake and ocean sediments , and carbonate speleothems . The character of deposition or rate of growth of the proxies ' material has been influenced by the climatic conditions of the time in which they were laid down or grew . Chemical traces produced by climatic changes , such as quantities of particular isotopes , can be recovered from proxies . Some proxies , such as gas bubbles trapped in ice , enable traces of the ancient atmosphere to be recovered and measured directly to provide a history of fluctuations in the composition of the Earth 's atmosphere . To produce the most precise results , systematic cross-verification between proxy indicators is necessary for accuracy in readings and record-keeping . Proxies can be combined to produce temperature reconstructions longer than the instrumental temperature record and can inform discussions of global warming . The distribution of proxy records , just like the instrumental record , is not at all uniform , with more records in the northern hemisphere . |
484 | Deforestation | "We almost take forests as a given but we lose forest every year, which means we are diminishing them as a carbon sink. | Deforestation Deforestation , clearance or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use . Examples of deforestation include conversion of forestland to farms , ranches , or urban use . The most concentrated deforestation occurs in tropical rainforests . About 30 % of Earth 's land surface is covered by forests . Deforestation occurs for multiple reasons : trees are cut down to be used for building or sold as fuel , ( sometimes in the form of charcoal or timber ) , while cleared land is used as pasture for livestock and plantation . The removal of trees without sufficient reforestation has resulted in damage to habitat , biodiversity loss and aridity . It has adverse impacts on biosequestration of atmospheric carbon dioxide . Deforestation has also been used in war to deprive the enemy of vital resources and cover for its forces . Modern examples of this were the use of Agent Orange by the British military in Malaya during the Malayan Emergency and the United States military in Vietnam during the Vietnam War . As of 2005 , net deforestation rates have ceased to increase in countries with a per capita GDP of at least US$ 4,600 . Deforested regions typically incur significant adverse soil erosion and frequently degrade into wasteland . Disregard of ascribed value , lax forest management and deficient environmental laws are some of the factors that allow deforestation to occur on a large scale . In many countries , deforestation , both naturally occurring and human-induced , is an ongoing issue . Deforestation causes extinction , changes to climatic conditions , desertification , and displacement of populations as observed by current conditions and in the past through the fossil record . More than half of all plant and land animal species in the world live in tropical forests . Between 2000 and 2012 , 2.3 e6sqkm of forests around the world were cut down . As a result of deforestation , only 6.2 e6km2 remain of the original 16 e6km2 of forest that formerly covered the Earth . |
100 | Global_warming | 'Global warming' is a myth — so say 80 graphs from 58 peer-reviewed scientific papers published in 2017. | 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 . |
1394 | Mountain_pine_beetle | U.S. Forest Service data show pine beetle infestations have recently declined dramatically throughout the western United States. | Mountain pine beetle The mountain pine beetle Dendroctonus ponderosae , is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia . It has a hard black exoskeleton , and measures approximately 5 mm , about the size of a grain of rice . In western North America , the current outbreak of the mountain pine beetle and its microbial associates has destroyed wide areas of lodgepole pine forest , including more than 16 million of the 55 million hectares of forest in British Columbia . The current outbreak in the Rocky Mountain National Park began in 1996 and has caused the destruction of millions of acres of ponderosa and lodgepole pine trees . According to an annual assessment by the state 's forest service , 264,000 acres of trees in Colorado were infested by the mountain pine beetle at the beginning of 2013 . This was much smaller than the 1.15 million acres that were affected in 2008 because the beetle has already killed off most of the vulnerable trees ( Ward ) . Mountain pine beetles inhabit ponderosa , whitebark , lodgepole , Scotch , jack pine , and limber pine trees . Normally , these insects play an important role in the life of a forest , attacking old or weakened trees , and speeding development of a younger forest . However , unusually hot , dry summers and mild winters throughout the region during the last few years , along with forests filled with mature lodgepole pine , have led to an unprecedented epidemic . It may be the largest forest insect blight ever seen in North America . Climate change , monocultural replanting , and a century of forest fire suppresion have contributed to the size and severity of the outbreak , and the outbreak itself may , with similar infestations , have significant effects on the capability of northern forests to remove greenhouse gas ( CO2 ) from the atmosphere . Because of its impact on forestry , the transcriptome and the genome have been sequenced . This is only the second beetle genome to be sequenced as of 2013 . |
44 | Global_warming_controversy | Human-produced carbon might be one of the factors [of climate change], but there's simply no evidence that it is a significant one. | Global warming controversy The global warming controversy concerns the public debate over whether global warming is occurring , how much has occurred in modern times , what has caused it , what its effects will be , whether any action should be taken to curb it , and if so what that action should be . In the scientific literature , there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases . No scientific body of national or international standing disagrees with this view , though a few organizations with members in extractive industries hold non-committal positions . Disputes over the key scientific facts of global warming are more prevalent in the media than in the scientific literature , where such issues are treated as resolved , and such disputes are more prevalent in the United States than globally . Political and popular debate concerning the existence and cause of climate change includes the reasons for the increase seen in the instrumental temperature record , whether the warming trend exceeds normal climatic variations , and whether human activities have contributed significantly to it . Scientists have resolved these questions decisively in favour of the view that the current warming trend exists and is ongoing , that human activity is the cause , and that it is without precedent in at least 2000 years . Public disputes that also reflect scientific debate include estimates of how responsive the climate system might be to any given level of greenhouse gases ( climate sensitivity ) , how global climate change will play out at local and regional scales , and what the consequences of global warming will be . Global warming remains an issue of widespread political debate , often split along party political lines , especially in the United States . Many of the issues that are settled within the scientific community , such as human responsibility for global warming , remain the subject of politically or economically motivated attempts to downplay , dismiss or deny them -- an ideological phenomenon categorised by academics and scientists as climate change denial . The sources of funding for those involved with climate science -- both supporting and opposing mainstream scientific positions -- have been questioned by both sides . There are debates about the best policy responses to the science , their cost-effectiveness and their urgency . Climate scientists , especially in the United States , have reported official and oil-industry pressure to censor or suppress their work and hide scientific data , with directives not to discuss the subject in public communications . Legal cases regarding global warming , its effects , and measures to reduce it have reached American courts . The fossil fuels lobby has been identified as overtly or covertly supporting efforts to undermine or discredit the scientific consensus on global warming . |
31 | Paleocene–Eocene_Thermal_Maximum | Discovery Of Massive Volcanic CO2 Emissions Discredits Global Warming Theory | Paleocene–Eocene Thermal Maximum The Paleocene -- Eocene Thermal Maximum ( PETM ) , alternatively ( ETM1 ) , and formerly known as the `` Initial Eocene '' or '' '' was a time period with more than 8 ° C warmer global average temperature than today . This climate event began at the time boundary between the Paleocene and Eocene geological epochs . The exact age and duration of the event is uncertain but it is estimated to have occurred around 55.5 million years ago . The associated period of massive carbon injection into the atmosphere has been estimated to have lasted no longer than 20,000 years . The entire warm period lasted for about 200,000 years . Global temperatures increased by 5 -- 8 ° C . The carbon dioxide was likely released in two pulses , the first lasting less than 2,000 years . Such a repeated carbon release is in line with current global warming . A main difference is that during the Paleocene -- Eocene Thermal Maximum , the planet was essentially ice-free . The onset of the Paleocene -- Eocene Thermal Maximum has been linked to an initial 5 ° C temperature rise and to extreme changes in Earth 's carbon cycle . The period is marked by a prominent negative excursion in carbon stable isotope records from around the globe ; more specifically , there was a large decrease in 13C/12C ratio of marine and terrestrial carbonates and organic carbon . Stratigraphic sections of rock from this period reveal numerous other changes . Fossil records for many organisms show major turnovers . For example , in the marine realm , a mass extinction of benthic foraminifera , a global expansion of subtropical dinoflagellates , and an appearance of excursion , planktic foraminifera and calcareous nanofossils all occurred during the beginning stages of PETM . On land , modern mammal orders ( including primates ) suddenly appear in Europe and in North America . Sediment deposition changed significantly at many outcrops and in many drill cores spanning this time interval . At least since 1997 , the Paleocene -- Eocene Thermal Maximum has become a focal point of considerable geoscience research because it probably provides the best past analog by which to understand impacts of global climate warming and of massive carbon input to the ocean and atmosphere , including ocean acidification . Although it is now widely accepted that the PETM represents a `` case study '' for global warming and massive carbon input to Earth 's surface , the cause , details and overall significance of the event remain perplexing . |
2378 | Risk_management | The costs of inaction far outweigh the costs of mitigation. | Risk management Risk management is the identification , assessment , and prioritization of risks ( defined in ISO 31000 as the effect of uncertainty on objectives ) followed by coordinated and economical application of resources to minimize , monitor , and control the probability and/or impact of unfortunate events or to maximize the realization of opportunities . Risk management 's objective is to assure uncertainty does not deflect the endeavor from the business goals . Risks can come from various sources including uncertainty in financial markets , threats from project failures ( at any phase in design , development , production , or sustainment life-cycles ) , legal liabilities , credit risk , accidents , natural causes and disasters , deliberate attack from an adversary , or events of uncertain or unpredictable root-cause . There are two types of events i.e. negative events can be classified as risks while positive events are classified as opportunities . Several risk management standards have been developed including the Project Management Institute , the National Institute of Standards and Technology , actuarial societies , and ISO standards . Methods , definitions and goals vary widely according to whether the risk management method is in the context of project management , security , engineering , industrial processes , financial portfolios , actuarial assessments , or public health and safety . Strategies to manage threats ( uncertainties with negative consequences ) typically include avoiding the threat , reducing the negative effect or probability of the threat , transferring all or part of the threat to another party , and even retaining some or all of the potential or actual consequences of a particular threat , and the opposites for opportunities ( uncertain future states with benefits ) . Certain aspects of many of the risk management standards have come under criticism for having no measurable improvement on risk ; whereas the confidence in estimates and decisions seem to increase . For example , it has been shown that one in six IT projects experience cost overruns of 200 % on average , and schedule overruns of 70 % . |
2288 | Cosmic_ray | While the link between cosmic rays and cloud cover is yet to be confirmed, more importantly, there has been no correlation between cosmic rays and global temperatures over the last 30 years of global warming. | Cosmic ray Cosmic rays are high-energy radiation , mainly originating outside the Solar System . Upon impact with the Earth 's atmosphere , cosmic rays can produce showers of secondary particles that sometimes reach the surface . Composed primarily of high-energy protons and atomic nuclei , they are of mysterious origin . Data from the Fermi Space Telescope ( 2013 ) have been interpreted as evidence that a significant fraction of primary cosmic rays originate from the supernovae explosions of stars . Active galactic nuclei probably also produce cosmic rays . |
1674 | 20th_century | Early 20th century warming is due to several causes, including rising CO2. | 20th century The 20th century was a century that began on January 1 , 1901 and ended on December 31 , 2000 . It was the tenth and final century of the 2nd millennium . It is distinct from the century known as the 1900s which began on January 1 , 1900 , and ended on December 31 , 1999 . The 20th century was dominated by a chain of events that heralded significant changes in world history as to redefine the era : World War I and World War II , nuclear power and space exploration , nationalism and decolonization , the Cold War and post-Cold War conflicts ; intergovernmental organizations and cultural homogenization through developments in emerging transportation and communications technology ; poverty reduction and world population growth , awareness of environmental degradation , ecological extinction ; and the birth of the Digital Revolution . It saw great advances in communication and medical technology that by the late 1980s allowed for near-instantaneous worldwide computer communication and genetic modification of life . The term `` short twentieth century '' was coined to represent the events from 1914 to 1991 . Global total fertility rates , sea level rise and ecological collapses increased ; the resulting competition for land and dwindling resources accelerated deforestation , water depletion . and the mass extinction of half the world 's estimated nine million unique species and wildlife population ; consequences which are now being dealt with . It took all of human history up to 1804 for the world 's population to reach 1 billion ; world population reached an estimated 2 billion in 1927 ; by late 1999 , the global population reached 6 billion . Global literacy averaged 80 % ; global lifespan-averages exceeded 40 + years for the first time in history , with over half achieving 70 + years ( three decades longer than it was a century ago ) . |
2921 | National_Oceanic_and_Atmospheric_Administration | The tax-payer funded National Oceanic and Atmospheric Administration (NOAA) has become mired in fresh global warming data scandal involving numbers for the Great Lakes region that substantially ramp up averages." | National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration ( NOAA ; pronounced -LSB- ˈnoʊ.ə -RSB- , like `` Noah '' ) is an American scientific agency within the United States Department of Commerce focused on the conditions of the oceans and the atmosphere . NOAA warns of dangerous weather , charts seas , guides the use and protection of ocean and coastal resources , and conducts research to improve understanding and stewardship of the environment . In addition to its civilian employees , over 11,000 as of 2015 , NOAA research and operations are supported by 379 uniformed service members who make up the NOAA Commissioned Officer Corps . NOAA traces its history to the Coast Survey established by President Thomas Jefferson in 1807 . In its present form , it combined several scientific agencies in 1970 . The Acting Under Secretary of Commerce for Oceans and Atmosphere at the Department of Commerce and the agency 's interim administrator has been Benjamin Friedman since the end of the Obama administration on January 20 , 2017 . |
2289 | Instrumental_temperature_record | In fact, in recent years when cosmic rays should have been having their largest cooling effect on record, temperatures have been at their highest on record. | 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 . |
2641 | Scientific_consensus_on_climate_change | In a paper published online this week in the Journal of Geophysical Research-Atmosphere, economics professor Ross McKitrick says the resulting discrepancies may be leading to an overstatement of the role of greenhouse gases in the atmosphere. | 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. |
2618 | Complex_system | It fails to explain how we can have short-term positive feedback and long-term negative feedback. | Complex system A complex system is a system composed of many components which may interact with each other . In many cases it is useful to represent such a system as a network where the nodes represent the components and the links their interactions . Examples of complex systems are Earth 's global climate , organisms , the human brain , social and economic organizations ( like cities ) , an ecosystem , a living cell , and ultimately the entire universe . |
1962 | Water_on_Mars | Surface temperatures on Earth "have stabilized." | Water on Mars Almost all water on Mars today exists as ice , though it also exists in small quantities as vapor in the atmosphere and occasionally as low-volume liquid brines in shallow Martian soil . The only place where water ice is visible at the surface is at the north polar ice cap . Abundant water ice is also present beneath the permanent carbon dioxide ice cap at the Martian south pole and in the shallow subsurface at more temperate latitudes . More than five million cubic kilometers of ice have been identified at or near the surface of modern Mars , enough to cover the whole planet to a depth of 35 meters . Even more ice is likely to be locked away in the deep subsurface . Some liquid water may occur transiently on the Martian surface today , but only under certain conditions . No large standing bodies of liquid water exist , because the atmospheric pressure at the surface averages just 600 Pa -- about 0.6 % of Earth 's mean sea level pressure -- and because the global average temperature is far too low ( 210 K ) , leading to either rapid evaporation ( sublimation ) or rapid freezing . Before about 3.8 billion years ago , Mars may have had a denser atmosphere and higher surface temperatures , allowing vast amounts of liquid water on the surface , possibly including a large ocean that may have covered one-third of the planet . Water has also apparently flowed across the surface for short periods at various intervals more recently in Mars ' history . On December 9 , 2013 , NASA reported that , based on evidence from the Curiosity rover studying Aeolis Palus , Gale Crater contained an ancient freshwater lake that could have been a hospitable environment for microbial life . Many lines of evidence indicate that water is abundant on Mars and has played a significant role in the planet 's geologic history . The present-day inventory of water on Mars can be estimated from spacecraft imagery , remote sensing techniques ( spectroscopic measurements , radar , etc. ) , and surface investigations from landers and rovers . Geologic evidence of past water includes enormous outflow channels carved by floods , ancient river valley networks , deltas , and lakebeds ; and the detection of rocks and minerals on the surface that could only have formed in liquid water . Numerous geomorphic features suggest the presence of ground ice ( permafrost ) and the movement of ice in glaciers , both in the recent past and present . Gullies and slope lineae along cliffs and crater walls suggest that flowing water continues to shape the surface of Mars , although to a far lesser degree than in the ancient past . Although the surface of Mars was periodically wet and could have been hospitable to microbial life billions of years ago , the current environment at the surface is dry and subfreezing , probably presenting an insurmountable obstacle for living organisms . In addition , Mars lacks a thick atmosphere , ozone layer , and magnetic field , allowing solar and cosmic radiation to strike the surface unimpeded . The damaging effects of ionizing radiation on cellular structure is another one of the prime limiting factors on the survival of life on the surface . Therefore , the best potential locations for discovering life on Mars may be in subsurface environments . On November 22 , 2016 , NASA reported finding a large amount of underground ice on the planet Mars -- the volume of water detected is equivalent to the volume of water in Lake Superior . Understanding water on Mars is vital to assess the planet 's potential for harboring life and for providing usable resources for future human exploration . For this reason , ` Follow the Water ' was the science theme of NASA 's Mars Exploration Program ( MEP ) in the first decade of the 21st century . Discoveries by the 2001 Mars Odyssey , Mars Exploration Rovers ( MERs ) , Mars Reconnaissance Orbiter ( MRO ) , and Mars Phoenix lander have been instrumental in answering key questions about water 's abundance and distribution on Mars . The ESA 's Mars Express orbiter has also provided essential data in this quest . The Mars Odyssey , Mars Express , MER Opportunity rover , MRO , and Mars Science Lander Curiosity rover are still sending back data from Mars , and discoveries continue to be made . |
1796 | Natural_environment | Natural cycles superimposed on a linear warming trend can be mistaken for step changes, but the underlying warming is caused by the external radiative forcing. | Natural environment The natural environment encompasses all living and non-living things occurring naturally , meaning in this case not artificial . The term is most often applied to the Earth or some parts of Earth . This environment encompasses the interaction of all living species , climate , weather , and natural resources that affect human survival and economic activity . The concept of the natural environment can be distinguished by components : Complete ecological units that function as natural systems without massive civilized human intervention , including all vegetation , microorganisms , soil , rocks , atmosphere , and natural phenomena that occur within their boundaries and their nature Universal natural resources and physical phenomena that lack clear-cut boundaries , such as air , water , and climate , as well as energy , radiation , electric charge , and magnetism , not originating from civilized human activity In contrast to the natural environment is the built environment . In such areas where man has fundamentally transformed landscapes such as urban settings and agricultural land conversion , the natural environment is greatly modified into a simplified human environment . Even acts which seem less extreme , such as building a mud hut or a photovoltaic system in the desert , modify the natural environment into an artificial one . Though many animals build things to provide a better environment for themselves , they are not human , hence beaver dams and the works of Mound-building termites are thought of as natural . People seldom find absolutely natural environments on Earth , and naturalness usually varies in a continuum , from 100 % natural in one extreme to 0 % natural in the other . More precisely , we can consider the different aspects or components of an environment , and see that their degree of naturalness is not uniform . If , for instance , in an agricultural field , the mineralogic composition and the structure of its soil are similar to those of an undisturbed forest soil , but the structure is quite different . Natural environment is often used as a synonym for habitat . For instance , when we say that the natural environment of giraffes is the savanna . |
1981 | Environmental_policy_of_the_Donald_Trump_administration | The EPA director under Obama said the Clean Power Initiative would have no effect on man-made CO2 emissions. | Environmental policy of the Donald Trump administration The environmental policy of the Donald Trump administration represents a shift from the policy priorities and goals of his predecessor , Barack Obama . During the campaign Trump often described environmental regulations as an impediment to business . He promised to roll back many regulations and end a moratorium on the leasing of federal coal reserves . Immediately upon his inauguration , the White House released an `` America First Energy Plan '' , which focused on fossil fuels and did not mention renewable energy . The plan would repeal many Obama policies including the Climate Action Plan and the Waters of the U.S. rule , and limit the Environmental Protection Agency 's mission to protecting air and water quality . Within days of taking office he signed executive orders to approve two controversial pipelines and to require federal review of the Clean Water Rule and the Clean Power Plan . He also invited American manufacturers to suggest what regulations should be eliminated ; industry leaders submitted 168 comments , of which nearly half targeted Environmental Protection Agency rules . In March 2017 he released a proposed 2018 budget which would cut funding for the EPA by 31 % . In May 2017 Congress approved a budget for the balance of the 2017-18 year which cuts the EPA 's funding by 1 % and eliminates no jobs . Trump 's appointments to key agencies dealing in energy and environmental policy reflected his commitment to deregulation , particularly of the fossil fuel industry . Several of his cabinet picks , such as Rick Perry as Secretary of Energy and Scott Pruitt as Administrator of the Environmental Protection Agency , were of people with a history of opposition to the agency they were named to head . |
373 | Human_impact_on_the_environment | Like countless other organisms, we move and adapt when the environment changes. | Human impact on the environment Human impact on the environment or anthropogenic impact on the environment includes impacts on biophysical environments , biodiversity , and other resources . The term anthropogenic designates an effect or object resulting from human activity . The term was first used in the technical sense by Russian geologist Alexey Pavlov , and was first used in English by British ecologist Arthur Tansley in reference to human influences on climax plant communities . The atmospheric scientist Paul Crutzen introduced the term `` Anthropocene '' in the mid-1970s . The term is sometimes used in the context of pollution emissions that are produced as a result of human activities but applies broadly to all major human impacts on the environment . |
2799 | Global_dimming | satellites confirmed measurements from ground stations show a considerable, and naturally-occurring, global brightening from 1983-2001 (Pinker et al., 2005). | Global dimming Global dimming is the gradual reduction in the amount of global direct irradiance at the Earth 's surface that was observed for several decades after the start of systematic measurements in the 1950s . The effect varies by location , but worldwide it has been estimated to be of the order of a 4 % reduction over the three decades from 1960 -- 1990 . However , after discounting an anomaly caused by the eruption of Mount Pinatubo in 1991 , a very slight reversal in the overall trend has been observed . Global dimming is thought to have been caused by an increase in particulates such as sulfate aerosols in the atmosphere due to human action . It has interfered with the hydrological cycle by reducing evaporation and may have reduced rainfall in some areas . Global dimming also creates a cooling effect that may have partially counteracted the effect of greenhouse gases on global warming . |
1618 | 20th_century | We didn't have global warming during the Industrial Revolution. | 20th century The 20th century was a century that began on January 1 , 1901 and ended on December 31 , 2000 . It was the tenth and final century of the 2nd millennium . It is distinct from the century known as the 1900s which began on January 1 , 1900 , and ended on December 31 , 1999 . The 20th century was dominated by a chain of events that heralded significant changes in world history as to redefine the era : World War I and World War II , nuclear power and space exploration , nationalism and decolonization , the Cold War and post-Cold War conflicts ; intergovernmental organizations and cultural homogenization through developments in emerging transportation and communications technology ; poverty reduction and world population growth , awareness of environmental degradation , ecological extinction ; and the birth of the Digital Revolution . It saw great advances in communication and medical technology that by the late 1980s allowed for near-instantaneous worldwide computer communication and genetic modification of life . The term `` short twentieth century '' was coined to represent the events from 1914 to 1991 . Global total fertility rates , sea level rise and ecological collapses increased ; the resulting competition for land and dwindling resources accelerated deforestation , water depletion . and the mass extinction of half the world 's estimated nine million unique species and wildlife population ; consequences which are now being dealt with . It took all of human history up to 1804 for the world 's population to reach 1 billion ; world population reached an estimated 2 billion in 1927 ; by late 1999 , the global population reached 6 billion . Global literacy averaged 80 % ; global lifespan-averages exceeded 40 + years for the first time in history , with over half achieving 70 + years ( three decades longer than it was a century ago ) . |
2488 | Phenology | However, it is unable to explain the long term warming trend over the past few decades. | Phenology Phenology is the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate , as well as habitat factors ( such as elevation ) . The word , coined by the Belgian botanist Charles Morren around 1849 , is derived from the Greek φαίνω ( phainō ) , `` to show , to bring to light , make to appear '' + λόγος ( logos ) , amongst others `` study , discourse , reasoning '' and indicates that phenology has been principally concerned with the dates of first occurrence of biological events in their annual cycle . Examples include the date of emergence of leaves and flowers , the first flight of butterflies and the first appearance of migratory birds , the date of leaf colouring and fall in deciduous trees , the dates of egg-laying of birds and amphibia , or the timing of the developmental cycles of temperate-zone honey bee colonies . In the scientific literature on ecology , the term is used more generally to indicate the time frame for any seasonal biological phenomena , including the dates of last appearance ( e.g. , the seasonal phenology of a species may be from April through September ) . Because many such phenomena are very sensitive to small variations in climate , especially to temperature , phenological records can be a useful proxy for temperature in historical climatology , especially in the study of climate change and global warming . For example , viticultural records of grape harvests in Europe have been used to reconstruct a record of summer growing season temperatures going back more than 500 years . In addition to providing a longer historical baseline than instrumental measurements , phenological observations provide high temporal resolution of ongoing changes related to global warming . |
1619 | James_Hansen | Hansen predicted in 1988 the West Side Highway would be underwater in 20 years. | James Hansen James Edward Hansen ( born 29 March 1941 ) is an American adjunct professor in the Department of Earth and Environmental Sciences at Columbia University . He is best known for his research in climatology , his 1988 Congressional testimony on climate change that helped raise broad awareness of global warming , and his advocacy of action to avoid dangerous climate change . In recent years he has become a climate activist to mitigate the effects of climate change , on a few occasions leading to his arrest . In 2000 , Hansen advanced an alternative view of global warming over the last 100 years , arguing that during that time frame the negative forcing via aerosols and the positive forcing via largely balanced each other out , and that the 0.74 ± 0.18 ° C net rise in average global temperatures could mostly be explained by greenhouse gases other than carbon dioxide , such as methane and chlorofluorocarbons . However , even then he wrote `` the future balance of forcings is likely to shift toward dominance of CO2 over aerosols '' |
356 | Risk | This requires us to work towards avoiding catastrophic possibilities rather than looking at probabilities, as learning from mistakes is not an option when it comes to existential risks. | Risk Risk is the potential of gaining or losing something of value . Values ( such as physical health , social status , emotional well-being , or financial wealth ) can be gained or lost when taking risk resulting from a given action or inaction , foreseen or unforeseen . Risk can also be defined as the intentional interaction with uncertainty . Uncertainty is a potential , unpredictable , and uncontrollable outcome ; risk is a consequence of action taken in spite of uncertainty . Risk perception is the subjective judgment people make about the severity and probability of a risk , and may vary person to person . Any human endeavor carries some risk , but some are much riskier than others . |
1798 | Global_warming | A few degrees of global warming has a huge impact on ice sheets, sea levels and other aspects of climate. | 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 . |
564 | Paris_Agreement | This could mean the landmark Paris Climate Agreement – which seeks to limit global warming to 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels – may not be enough to ward off catastrophe. | Paris Agreement The Paris Agreement ( Accord de Paris ) is an agreement within the United Nations Framework Convention on Climate Change ( UNFCCC ) dealing with greenhouse gas emissions mitigation , adaptation and finance starting in the year 2020 . The language of the agreement was negotiated by representatives of 195 countries at the 21st Conference of the Parties of the UNFCCC in Paris and adopted by consensus on 12 December 2015 . It was opened for signature on 22 April 2016 ( Earth Day ) at a ceremony in New York . As of May 2017 , 195 UNFCCC members have signed the treaty , 147 of which have ratified it . After several European Union states ratified the agreement in October 2016 , there were enough countries that had ratified the agreement that produce enough of the world 's greenhouse gases for the agreement to enter into force . The agreement went into effect on 4 November 2016 . The head of the Paris Conference , France 's foreign minister Laurent Fabius , said this `` ambitious and balanced '' plan is a `` historic turning point '' in the goal of reducing global warming . One year on , the ratification of the Paris Agreement was celebrated by the Mayor of Paris Anne Hidalgo by illuminating the Eiffel Tower and the Arc de Triomphe , Paris ' most iconic monuments , in green . |
534 | Paris_Agreement | Domino-effect of climate events could move Earth into a 'hothouse' state | Paris Agreement The Paris Agreement ( Accord de Paris ) is an agreement within the United Nations Framework Convention on Climate Change ( UNFCCC ) dealing with greenhouse gas emissions mitigation , adaptation and finance starting in the year 2020 . The language of the agreement was negotiated by representatives of 195 countries at the 21st Conference of the Parties of the UNFCCC in Paris and adopted by consensus on 12 December 2015 . It was opened for signature on 22 April 2016 ( Earth Day ) at a ceremony in New York . As of May 2017 , 195 UNFCCC members have signed the treaty , 147 of which have ratified it . After several European Union states ratified the agreement in October 2016 , there were enough countries that had ratified the agreement that produce enough of the world 's greenhouse gases for the agreement to enter into force . The agreement went into effect on 4 November 2016 . The head of the Paris Conference , France 's foreign minister Laurent Fabius , said this `` ambitious and balanced '' plan is a `` historic turning point '' in the goal of reducing global warming . One year on , the ratification of the Paris Agreement was celebrated by the Mayor of Paris Anne Hidalgo by illuminating the Eiffel Tower and the Arc de Triomphe , Paris ' most iconic monuments , in green . |
1227 | Salt_marsh | These tidal floods are often just a foot or two deep, but they can stop traffic, swamp basements, damage cars, kill lawns and forests, and poison wells with salt. | Salt marsh A salt marsh or saltmarsh , also known as a coastal salt marsh or a tidal marsh , is a coastal ecosystem in the upper coastal intertidal zone between land and open salt water or brackish water that is regularly flooded by the tides . It is dominated by dense stands of salt-tolerant plants such as herbs , grasses , or low shrubs . These plants are terrestrial in origin and are essential to the stability of the salt marsh in trapping and binding sediments . Salt marshes play a large role in the aquatic food web and the delivery of nutrients to coastal waters . They also support terrestrial animals and provide coastal protection . |
1477 | Scientific_consensus_on_climate_change | Human-produced carbon might be one of the factors of climate change, but there's simply no evidence that it is a significant one. | 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. |
1620 | Crown-of-thorns_starfish | Great Barrier Reef is in good shape. | Crown-of-thorns starfish The crown-of-thorns starfish , Acanthaster planci , is a large , multiple-armed starfish that usually preys upon hard , or stony , coral polyps ( Scleractinia ) . The crown-of-thorns starfish receives its name from venomous thorn-like spines that cover its upper surface , resembling the biblical crown of thorns . It is one of the largest starfish in the world . A. planci has a very wide Indo-Pacific distribution . It is perhaps most common in Australia , but can occur at tropical and subtropical latitudes from the Red Sea and the east African coast across the Indian Ocean , and across the Pacific Ocean to the west coast of Central America . It occurs where coral reefs or hard coral communities occur in this region . |
2591 | Heat_transfer | 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. | Heat transfer Heat transfer is a discipline of thermal engineering that concerns the generation , use , conversion , and exchange of thermal energy and heat between physical systems . Heat transfer is classified into various mechanisms , such as thermal conduction , thermal convection , thermal radiation , and transfer of energy by phase changes . Engineers also consider the transfer of mass of differing chemical species , either cold or hot , to achieve heat transfer . While these mechanisms have distinct characteristics , they often occur simultaneously in the same system . Heat conduction , also called diffusion , is the direct microscopic exchange of kinetic energy of particles through the boundary between two systems . When an object is at a different temperature from another body or its surroundings , heat flows so that the body and the surroundings reach the same temperature , at which point they are in thermal equilibrium . Such spontaneous heat transfer always occurs from a region of high temperature to another region of lower temperature , as described by the second law of thermodynamics . Heat convection occurs when bulk flow of a fluid ( gas or liquid ) carries heat along with the flow of matter in the fluid . The flow of fluid may be forced by external processes , or sometimes ( in gravitational fields ) by buoyancy forces caused when thermal energy expands the fluid ( for example in a fire plume ) , thus influencing its own transfer . The latter process is often called `` natural convection '' . All convective processes also move heat partly by diffusion , as well . Another form of convection is forced convection . In this case the fluid is forced to flow by use of a pump , fan or other mechanical means . Thermal radiation occurs through a vacuum or any transparent medium ( solid or fluid ) . It is the transfer of energy by means of photons in electromagnetic waves governed by the same laws . |
1555 | El_Niño | Climate change is because of El Niño. | El Niño El Niño -LSB- ɛl_ˈniːnjoʊ -RSB- ( -LSB- el ˈniɲo -RSB- ) is the warm phase of the El Niño Southern Oscillation ( commonly called ENSO ) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific ( between approximately the International Date Line and 120 ° W ) , including off the Pacific coast of South America . El Niño Southern Oscillation refers to the cycle of warm and cold temperatures , as measured by sea surface temperature , SST , of the tropical central and eastern Pacific Ocean . El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific . The cool phase of ENSO is called `` La Niña '' with SST in the eastern Pacific below average and air pressures high in the eastern and low in western Pacific . The ENSO cycle , both El Niño and La Niña , cause global changes of both temperatures and rainfall . Developing countries that are dependent upon agriculture and fishing , particularly those bordering the Pacific Ocean , are usually most affected . In American Spanish , the capitalized term `` El Niño '' refers to `` the little boy '' , so named because the pool of warm water in the Pacific near South America is often at its warmest around Christmas . The original name , `` El Niño de Navidad '' , traces its origin centuries back to Peruvian fisherman , who named the weather phenomenon in reference to the newborn Christ . `` La Niña '' , chosen as the ` opposite ' of El Niño , literally translates to `` the little girl '' . |
482 | IPCC_Fourth_Assessment_Report | It is expected the report will focus on required changes to the energy system, rather than forests. | IPCC Fourth Assessment Report Climate Change 2007 , the Fourth Assessment Report ( AR4 ) of the United Nations Intergovernmental Panel on Climate Change ( IPCC ) , is the fourth in a series of reports intended to assess scientific , technical and socio-economic information concerning climate change , its potential effects , and options for adaptation and mitigation . The report is the largest and most detailed summary of the climate change situation ever undertaken , produced by thousands of authors , editors , and reviewers from dozens of countries , citing over 6,000 peer-reviewed scientific studies . It supersedes the Third Assessment Report ( 2001 ) , and is superseded by the Fifth Assessment Report . The headline findings of the report were : `` warming of the climate system is unequivocal '' , and `` most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations . '' |
1912 | Julia_Gillard | Julia Gillard her decision not to argue against a fixed carbon price being labelled a "carbon tax" hurt her terribly politically. | Julia Gillard Julia Eileen Gillard , ( born 29 September 1961 ) is a former Australian politician who was the 27th Prime Minister of Australia from 2010 to 2013 , as leader of the Australian Labor Party . She was previously the 13th Deputy Prime Minister of Australia , and held the cabinet positions of Minister for Education , Minister for Employment and Workplace Relations and Minister for Social Inclusion from 2007 to 2010 . She was the first and to date only woman to hold the positions of deputy prime minister , prime minister and leader of a major party in Australia . Born in Barry , Wales , in the United Kingdom , Gillard migrated with her family to Adelaide , South Australia , in 1966 . She attended Mitcham Demonstration School and Unley High School . Subsequently , Gillard studied at the University of Adelaide , but cut short her courses to move to Melbourne , Victoria , in 1982 , where she worked with the Australian Union of Students and was the organisation 's president from 1983 to 1984 . Gillard later graduated from the University of Melbourne , with a Bachelor of Laws degree ( 1986 ) and a Bachelor of Arts degree ( 1989 ) . In 1987 , she joined the law firm Slater & Gordon and became a partner in 1990 , specialising in industrial law . A departure from the law firm in 1996 saw Gillard serve as chief of staff to the Leader of the Opposition in Victoria John Brumby , which preceded her own entry into federal politics . Gillard was first elected to the Australian House of Representatives at the 1998 federal election for the seat of Lalor . Following the 2001 federal election , she was elected to the Shadow Cabinet and was given the portfolio of Population and Immigration . In 2003 , she took on the responsibility for both Reconciliation and Indigenous Affairs and Health . In December 2006 , when Kevin Rudd was elected as Labor Leader and became Leader of the Opposition , Gillard was elected unopposed as his deputy . Upon Labor 's victory in the 2007 federal election , Gillard became the first female Deputy Prime Minister of Australia , and held the cabinet portfolios of Minister for Education , Minister for Employment and Workplace Relations and Minister for Social Inclusion . On , after Rudd lost the support of his party and resigned , Gillard was elected unopposed as the Leader of the Labor Party , thus becoming the 27th Prime Minister of Australia . The subsequent 2010 federal election saw the first hung parliament since the 1940 federal election . Gillard was able to form a minority government with the support of a Green MP and three independent MPs . On 26 June 2013 , after a leadership spill , Gillard lost the leadership of the Labor Party to Rudd . Her resignation as Prime Minister took effect the following day . Gillard retired from politics on 5 August 2013 , before the impending federal election . Following her departure from politics , in August 2013 Gillard became an honorary visiting professor at the University of Adelaide , and a nonresident senior fellow at the Brookings Institution 's Center for Universal Education in October . Gillard released her political memoirs , My Story , in September 2014 . She has been on the board of the mental health organisation beyondblue since December 2014 , and was made an honorary fellow of Aberystwyth University in June 2015 . In addition to her various appointments , Gillard has served as the chairwoman of the Global Partnership for Education since February 2014 . |
1715 | Climate_change_feedback | Theory, models and direct measurement confirm CO2 is currently the main driver of climate change. | 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 . '' |
95 | Effects_of_global_warming | [climate scientists] say that aspects of the case of Hurricane Harvey suggest global warming is making a bad situation worse. | Effects of global warming The effects of global warming are the environmental and social changes caused ( directly or indirectly ) by human emissions of greenhouse gases . There is a scientific consensus that climate change is occurring , and that human activities are the primary driver . Many impacts of climate change have already been observed , including glacier retreat , changes in the timing of seasonal events ( e.g. , earlier flowering of plants ) , and changes in agricultural productivity . Future effects of climate change will vary depending on climate change policies and social development . The two main policies to address climate change are reducing human greenhouse gas emissions ( climate change mitigation ) and adapting to the impacts of climate change . Geoengineering is another policy option . Near-term climate change policies could significantly affect long-term climate change impacts . Stringent mitigation policies might be able to limit global warming ( in 2100 ) to around 2 ° C or below , relative to pre-industrial levels . Without mitigation , increased energy demand and extensive use of fossil fuels might lead to global warming of around 4 ° C. Higher magnitudes of global warming would be more difficult to adapt to , and would increase the risk of negative impacts . |
113 | Global_warming_controversy | The temperature is not rising nearly as fast as the alarmist computer models predicted. | 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 . |
1056 | Ozone_depletion | Because oxygen in the global ocean is not evenly distributed, the 2 percent overall decline means there is a much larger decline in some areas of the ocean than others. | Ozone depletion Ozone depletion describes two distinct but related phenomena observed since the late 1970s : a steady decline of about four percent in the total amount of ozone in Earth 's stratosphere ( the ozone layer ) , and a much larger springtime decrease in stratospheric ozone around Earth 's polar regions . The latter phenomenon is referred to as the ozone hole . In addition to these well-known stratospheric phenomena , there are also springtime polar tropospheric ozone depletion events . The details of polar ozone hole formation differ from that of mid-latitude thinning but the most important process in both is catalytic destruction of ozone by atomic halogens . The main source of these halogen atoms in the stratosphere is photodissociation of man-made halocarbon refrigerants , solvents , propellants , and foam-blowing agents ( chlorofluorocarbon ( CFCs ) , HCFCs , freons , halons ) . These compounds are transported into the stratosphere by winds after being emitted at the surface . Both types of ozone depletion were observed to increase as emissions of halocarbons increased . CFCs and other contributory substances are referred to as ozone-depleting substances ( ODS ) . Since the ozone layer prevents most harmful UVB wavelengths ( 280 -- 315 nm ) of ultraviolet light ( UV light ) from passing through the Earth 's atmosphere , observed and projected decreases in ozone generated worldwide concern , leading to adoption of the Montreal Protocol that bans the production of CFCs , halons , and other ozone-depleting chemicals such as carbon tetrachloride and trichloroethane . It is suspected that a variety of biological consequences such as increases in sunburn , skin cancer , cataracts , damage to plants , and reduction of plankton populations in the ocean 's photic zone may result from the increased UV exposure due to ozone depletion . |
2611 | Carbon_price | The final amount of extra CO2 that remains in the atmosphere stays there on a time scale of centuries. | Carbon price Carbon pricing -- the method favored by many economists for reducing global-warming emissions -- charges those who emit carbon dioxide ( CO2 ) for their emissions . That charge , called a carbon price , is the amount that must be paid for the right to emit one tonne of CO2 into the atmosphere . Carbon pricing usually takes the form either of a carbon tax or a requirement to purchase permits to emit , generally known as cap-and-trade , but also called `` allowances '' . Carbon pricing solves the economic problem that , a known greenhouse gas , is what economics calls a negative externality -- a detrimental product that is not priced ( charged for ) by any market . As a consequence of not being priced , there is no market mechanism responsive to the costs of CO2 emitted . The standard economic solution to problems of this type , first proposed by Arthur Pigou in 1920 , is for the product - in this case , CO2 emissions - to be charged at a price equal to the monetary value of the damage caused by the emissions . This should result in the economically optimal ( efficient ) amount of CO2 emissions . Many practical concerns mar the theoretical simplicity of this picture : for example , the exact monetary damage caused by a tonne of CO2 is uncertain . The economics of carbon pricing is much the same for taxes and cap-and-trade . Both prices are efficient ; they have the same social cost and the same effect on profits if permits are auctioned . However , some economists argue that caps prevent non-price policies , such as renewable energy subsidies , from reducing carbon emissions , while carbon taxes do not . Others argue that an enforced cap is the only way to guarantee that carbon emissions will actually be reduced ; a carbon tax will not prevent those who can afford to do so from continuing to generate emissions . The choice of pricing approach , a tax or cap-and-trade , has been controversial . A carbon tax is generally favored on economic grounds for its simplicity and stability , while cap-and-trade is often favored on political grounds . Recently ( 2013 − 14 ) economic opinion has been shifting more heavily toward taxes as national policy measures , and toward a neutral carbon-price-commitment position for the purpose of international climate negotiations . |
104 | Greenhouse_gas | Increases in atmospheric CO2 followed increases in temperature. | 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 . |
1919 | Arctic | Measurements indicating that 2017 had relatively more sea ice in the Arctic and less melting of glacial ice in Greenland casts scientific doubt on the reality of global warming. | 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 . |
1455 | Greenland_ice_sheet | The Greenland and Antarctic ice sheets have decreased in mass. | Greenland ice sheet The Greenland ice sheet ( Grønlands indlandsis , Sermersuaq ) is a vast body of ice covering 1710000 km ² , roughly 80 % of the surface of Greenland . It is the second largest ice body in the world , after the Antarctic ice sheet . The ice sheet is almost 2400 km long in a north-south direction , and its greatest width is 1100 km at a latitude of 77 ° N , near its northern margin . The mean altitude of the ice is 2135 m . The thickness is generally more than 2 km and over 3 km at its thickest point . It is not the only ice mass of Greenland -- isolated glaciers and small ice caps cover between 76000 and around the periphery . If the entire 2850000 km3 of ice were to melt , it would lead to a global sea level rise of 7.2 m . The Greenland Ice Sheet is sometimes referred to under the term inland ice , or its Danish equivalent , indlandsis . It is also sometimes referred to as an ice cap . |
846 | Arctic | In other words, we have, trapped in Arctic permafrost, twice as much carbon as is currently wrecking the atmosphere of the planet, all of it scheduled to be released at a date that keeps getting moved up, partially in the form of a gas that multiplies its warming power 86 times over. | 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 . |
988 | Indo-Aryan_migration | The unlikely scenarios are now, all of a sudden, becoming more probable than they once were thought to be,' says Sweet." | Indo-Aryan migration The Indo-Aryan migrations were the migrations into the Indian subcontinent of Indo-Aryan peoples, an ethnolinguistic group that spoke Indo-Aryan languages, the predominant languages of today's North India, Pakistan, Nepal, Bangladesh, Sri Lanka and the Maldives. Indo-Aryan population movements into the region and Anatolia (ancient Mitanni) from Central Asia are considered to have started after 2000 BCE, as a slow diffusion after the Late Harappan period, which led to a language shift in the northern Indian subcontinent. The Iranian languages were brought into the Iranian plateau by the Iranians, who were closely related to the Indo-Aryans. |
2100 | IPCC_Fourth_Assessment_Report | IPCC were wrong about Himalayan glaciers | IPCC Fourth Assessment Report Climate Change 2007 , the Fourth Assessment Report ( AR4 ) of the United Nations Intergovernmental Panel on Climate Change ( IPCC ) , is the fourth in a series of reports intended to assess scientific , technical and socio-economic information concerning climate change , its potential effects , and options for adaptation and mitigation . The report is the largest and most detailed summary of the climate change situation ever undertaken , produced by thousands of authors , editors , and reviewers from dozens of countries , citing over 6,000 peer-reviewed scientific studies . It supersedes the Third Assessment Report ( 2001 ) , and is superseded by the Fifth Assessment Report . The headline findings of the report were : `` warming of the climate system is unequivocal '' , and `` most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations . '' |
1541 | Sea_level | Sea level rise due to global warming is exaggerated. | Sea level Mean sea level ( MSL ) ( abbreviated simply sea level ) is an average level of the surface of one or more of Earth 's oceans from which heights such as elevations may be measured . MSL is a type of vertical datuma standardised geodetic reference pointthat is used , for example , as a chart datum in cartography and marine navigation , or , in aviation , as the standard sea level at which atmospheric pressure is measured in order to calibrate altitude and , consequently , aircraft flight levels . A common and relatively straightforward mean sea-level standard is the midpoint between a mean low and mean high tide at a particular location . Sea levels can be affected by many factors and are known to have varied greatly over geological time scales . The careful measurement of variations in MSL can offer insights into ongoing climate change , and sea level rise has been widely quoted as evidence of ongoing global warming . The term above sea level generally refers to above mean sea level ( AMSL ) . |
236 | Global_warming | global temperatures have risen between 0.23F (0.13C) and 0.34F (0.19C) per decade | 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 . |
1517 | Global_warming | Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver. | 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 . |
582 | Norway | On the other side of the Atlantic ocean, climates are typically milder as a result of the cooling from the Gulf Stream. | Norway Norway ( -LSB- Norgehelp = no -RSB- ( Bokmål ) or ( Nynorsk ) ) , officially the Kingdom of Norway , is a sovereign state and unitary monarchy whose territory comprises the western portion of the Scandinavian Peninsula plus the island Jan Mayen and the archipelago of Svalbard . The Antarctic Peter I Island and the sub-Antarctic Bouvet Island are dependent territories and thus not considered part of the Kingdom . Norway also lays claim to a section of Antarctica known as Queen Maud Land . Until 1814 , the kingdom included the Faroe Islands , Greenland and Iceland . It also included Bohuslän until 1658 , Jämtland and Härjedalen until 1645 , Shetland and Orkney until 1468 , and the Hebrides and Isle of Man until 1266 . Norway has a total area of 385252 km2 and a population of 5,258,317 ( as of January 2017 ) . The country shares a long eastern border with Sweden ( 1,619 km or 1,006 mi long ) . Norway is bordered by Finland and Russia to the north-east , and the Skagerrak Strait to the south , with Denmark on the other side . Norway has an extensive coastline , facing the North Atlantic Ocean and the Barents Sea . King Harald V of the Dano-German House of Glücksburg is the current King of Norway . Erna Solberg became Prime Minister in 2013 , replacing Jens Stoltenberg . A constitutional monarchy , Norway divides state power between the Parliament , the Cabinet and the Supreme Court , as determined by the 1814 Constitution . The kingdom is established as a merger of several petty kingdoms . By the traditional count from the year 872 , the kingdom has existed continuously for 1,144 years and the list of Norwegian monarchs includes over sixty kings and earls . Norway has both administrative and political subdivisions on two levels : counties and municipalities . The Sámi people have a certain amount of self-determination and influence over traditional territories through the Sámi Parliament and the Finnmark Act . Norway maintains close ties with the European Union and the United States . Norway is a founding member of the United Nations , NATO , the Council of Europe , the Antarctic Treaty and the Nordic Council ; a member of the European Economic Area , the WTO and the OECD ; and is also a part of the Schengen Area . The country maintains a combination of market economy and a Nordic welfare model with universal health care and a comprehensive social security system . Norway has extensive reserves of petroleum , natural gas , minerals , lumber , seafood , fresh water and hydropower . The petroleum industry accounts for around a quarter of the country 's gross domestic product ( GDP ) . On a per-capita basis , Norway is the world 's largest producer of oil and natural gas outside the Middle East . The country has the fourth-highest per capita income in the world on the World Bank and IMF lists . On the CIA 's GDP ( PPP ) per capita list ( 2015 estimate ) which includes territories and some regions , Norway ranks as number eleven . From 2001 to 2006 , and then again from 2009 to 2017 , Norway had the highest Human Development Index ranking in the world . It also has the highest inequality-adjusted ranking . Norway ranks first on the World Happiness Report , the OECD Better Life Index , the Index of Public Integrity and the Democracy Index . |
2036 | Attribution_of_recent_climate_change | The global surface mean temperature-change data no longer have any scientific value and are nothing more than a propaganda tool to the public. | 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 ) . |
1451 | Fahrenheit | The planet's average surface temperature has risen about 1.62 degrees Fahrenheit (0.9 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide and other human-made emissions into the atmosphere. | Fahrenheit Fahrenheit is a temperature scale based on one proposed in 1724 by Amsterdam-based physicist Daniel Gabriel Fahrenheit ( 1686 -- 1736 ) , after whom the scale is named . It uses the degree Fahrenheit ( symbol ° F ) as the unit . Several accounts of how he originally defined his scale exist . The lower defining point , 0 ° F , was established as the temperature of a solution of brine made from equal parts of ice and salt . Further limits were established as the melting point of ice ( 32 ° F ) and his best estimate of the average human body temperature ( 96 ° F , about 2.6 ° F less than the modern value due to a later redefinition of the scale ) . The scale is now usually defined by two fixed points : the temperature at which water freezes into ice is defined as 32 ° F , and the boiling point of water is defined to be 212 ° F , a 180 ° F separation , as defined at sea level and standard atmospheric pressure . By the end of the 20th century , Fahrenheit was used as the official temperature scale only in the United States ( including its unincorporated territories ) , its freely associated states in the Western Pacific ( Palau , the Federated States of Micronesia and the Marshall Islands ) , the Bahamas , Belize , and the Cayman Islands . All other countries in the world now use the Celsius scale , defined since 1954 by absolute zero being − 273.15 ° C and the triple point of water being at 0.01 ° C. |
2609 | Carbon_dioxide | Individual carbon dioxide molecules have a short life time of around 5 years in the atmosphere. | 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 . |
2000 | Republican_Party_(United_States) | There is not a single candidate in the Republican primary that thinks we should do anything about climate change. | Republican Party (United States) The Republican Party , commonly referred to as the GOP ( abbreviation for Grand Old Party ) , is one of the two major contemporary political parties in the United States , the other being its historic rival , the Democratic Party . The party is named after republicanism , the dominant value during the American Revolution . Founded by anti-slavery activists , modernists , ex-Whigs , and ex-Free Soilers in 1854 , the Republicans dominated politics nationally and in the majority of northern States for most of the period between 1860 and 1932 . There have been 19 Republican presidents , the most from any one party . The first was 16th president Abraham Lincoln , who served from 1861 to 1865 , when he was assassinated , and the most recent being 45th and current president Donald Trump , who took office on January 20 , 2017 . The Republican Party 's current ideology is American conservatism , which contrasts with the Democrats ' more progressive platform ( also called modern liberalism ) . Further , its platform involves support for free market capitalism , free enterprise , fiscal conservatism , a strong national defense , deregulation , and restrictions on labor unions . In addition to advocating for conservative economic policies , the Republican Party is socially conservative , and seeks to uphold traditional values based largely on Judeo-Christian ethics . The GOP was strongly committed to protectionism and tariffs from its founding until the 1930s , when it was based in the industrial Northeast and Midwest . Since 1952 there has been a reversal against protectionism and the party 's core support since the 1990s comes chiefly from the South , the Great Plains , the Mountain States and rural districts in the North . as well as from conservative Catholics , Mormons , and Evangelicals nationwide . As of 2017 , the Republican Party is documented as being at its strongest position politically since 1928 . In addition to holding the Presidency ( via Trump and Vice President Mike Pence ) , the Republicans control the 115th United States Congress , having majorities in both the House of Representatives and the Senate . The party also holds a majority of governorships ( 33/50 ) and state legislatures ( full control of 32/50 , split control of six others ) . |
805 | Bushfires_in_Australia | The answer lies in the summer's record-breaking heat, say wildfire experts. | Bushfires in Australia Bushfires in Australia are frequent events during the warmer months of the year , due to Australia 's mostly hot , dry climate . Each year , such fires impact extensive areas . On one hand , they can cause property damage and loss of human life . On the other hand , certain native flora in Australia have evolved to rely on bushfires as a means of reproduction , and fire events are an interwoven and an essential part of the ecology of the continent . For thousands of years , Indigenous Australians have used fire to foster grasslands for hunting and to clear tracks through dense vegetation . Major firestorms that result in severe loss of life are often named based on the day on which they occur , such as Ash Wednesday and Black Saturday . Some of the most intense , extensive and deadly bushfires commonly occur during droughts and heat waves , such as the 2009 Southern Australia heat wave , which precipitated the conditions during the 2009 Black Saturday bushfires in which 173 people lost their lives . Other major conflagrations include the 1983 Ash Wednesday bushfires , the 2003 Eastern Victorian alpine bushfires and the 2006 December Bushfires . Global warming is increasing the frequency and severity of bushfires . |
311 | Effects_of_global_warming_on_human_health | there has been no systematic increase in the frequency of extreme weather events, | Effects of global warming on human health The effects of global warming include effects on human health . The observed and projected increased frequency and severity of climate related impacts will further exacerbate the effects on human health . This article describes some of those effects on individuals and populations . |
614 | Köppen_climate_classification | The Rio Grande is a classic "feast or famine" river, with a dry year or two typically followed by a couple of wet years that allow for recovery. | Köppen climate classification Köppen climate classification is one of the most widely used climate classification systems . It was first published by Russian German climatologist Wladimir Köppen in 1884 , with several later modifications by Köppen , notably in 1918 and 1936 . Later , German climatologist Rudolf Geiger ( 1954 , 1961 ) collaborated with Köppen on changes to the classification system , which is thus sometimes called the Köppen -- Geiger climate classification system . The Köppen climate classification system has been further modified , within the Trewartha climate classification system in the middle 1960s ( revised in 1980 ) . The Trewartha system sought to create a more refined middle latitude climate zone , which was one of the criticisms of the Köppen system ( the C climate group was too broad ) . |
678 | Beef | In the process, the cows will emit much greenhouse gas, and they will consume far more calories in beans than they will yield in meat, meaning far more clearcutting of forests to farm cattle feed than would be necessary if the beans above were simply eaten by people." | Beef Beef is the culinary name for meat from cattle , particularly skeletal muscle . Humans have been eating beef since prehistoric times . Beef is an excellent source of high-quality protein and essential nutrients . Beef skeletal muscle meat can be cut into roasts , short ribs or steak ( filet mignon , sirloin steak , rump steak , rib steak , rib eye steak , hanger steak , etc. ) . Some cuts are processed ( corned beef or beef jerky ) , and trimmings , usually mixed with meat from older , leaner cattle , are ground , minced or used in sausages . The blood is used in some varieties of blood sausage . Other parts that are eaten include other muscles and offal , such as the oxtail , liver , tongue , tripe from the reticulum or rumen , glands ( particularly the pancreas and thymus , referred to as sweetbread ) , the heart , the brain ( although forbidden where there is a danger of bovine spongiform encephalopathy , BSE ) , the kidneys , and the tender testicles of the bull ( known in the United States as calf fries , prairie oysters , or Rocky Mountain oysters ) . Some intestines are cooked and eaten as-is , but are more often cleaned and used as natural sausage casings . The bones are used for making beef stock . Beef from steers and heifers is very similar . According to the most recent National Beef Quality Audit , heifer carcasses had slightly more marbling than steer carcasses , but USDA quality grade was not significantly different . Depending on economics , the number of heifers kept for breeding varies . The meat from older bulls is usually tougher , so it is frequently used for mince ( known as ground beef in the United States ) . Cattle raised for beef may be allowed to roam free on grasslands , or may be confined at some stage in pens as part of a large feeding operation called a feedlot ( or concentrated animal feeding operation ) , where they are usually fed a ration of grain , protein , roughage and a vitamin/mineral preblend . Beef is the third most widely consumed meat in the world , accounting for about 25 % of meat production worldwide , after pork and poultry at 38 % and 30 % respectively . In absolute numbers , the United States , Brazil , and the People 's Republic of China are the world 's three largest consumers of beef ; Uruguay , however , has the highest beef and veal consumption per capita , followed by Argentina and Brazil . According to the data from OECD , the average Uruguayan ate over 42 kg of beef or veal in 2014 , representing the highest beef/veal consumption per capita in the world . In comparison , the average American consumed only about 24 kg beef or veal in the same year , while African countries , such as Mozambique , Ghana , and Nigeria , consumed the least beef or veal per capita . Cows are considered holy in the culture of India and there are restrictions on selling and consumption of beef in much of India . Though India is the largest producer and exporter of buffalo meat in the world . In 2015 , the world 's largest exporters of beef , ( including buffalo meat ) , were India , Brazil and Australia . Beef production is also important to the economies of Uruguay , Canada , Paraguay , Mexico , Argentina , Belarus and Nicaragua . |
763 | Carbon_dioxide | And some plants – like algae which use carbon for photosynthesis – may even benefit. | 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 . |
1789 | Climate_change_mitigation | CO2 limits won't cool the planet, but they can make the difference between continued accelerating global warming to catastrophic levels vs. slowing and eventually stopping the warming at hopefully safe levels. | Climate change mitigation Climate change mitigation consists of actions to limit the magnitude or rate of long-term climate change . Climate change mitigation generally involves reductions in human ( anthropogenic ) emissions of greenhouse gases ( GHGs ) . Mitigation may also be achieved by increasing the capacity of carbon sinks , e.g. , through reforestation . Mitigation policies can substantially reduce the risks associated with human-induced global warming . According to the IPCC 's 2014 assessment report , `` Mitigation is a public good ; climate change is a case of the ` tragedy of the commons . Effective climate change mitigation will not be achieved if each agent ( individual , institution or country ) acts independently in its own selfish interest ( see international cooperation and emissions trading ) , suggesting the need for collective action . Some adaptation actions , on the other hand , have characteristics of a private good as benefits of actions may accrue more directly to the individuals , regions , or countries that undertake them , at least in the short term . Nevertheless , financing such adaptive activities remains an issue , particularly for poor individuals and countries . '' Examples of mitigation include phasing out fossil fuels by switching to low-carbon energy sources , such as renewable and nuclear energy , and expanding forests and other `` sinks '' to remove greater amounts of carbon dioxide from the atmosphere . Energy efficiency may also play a role , for example , through improving the insulation of buildings . Another approach to climate change mitigation is climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) . The ultimate objective of the UNFCCC is to stabilize atmospheric concentrations of GHGs at a level that would prevent dangerous human interference of the climate system . Scientific analysis can provide information on the impacts of climate change , but deciding which impacts are dangerous requires value judgments . In 2010 , Parties to the UNFCCC agreed that future global warming should be limited to below 2.0 ° C ( 3.6 ° F ) relative to the pre-industrial level . With the Paris Agreement of 2015 this was confirmed , but was revised with a new target laying down `` parties will do the best '' to achieve warming below 1.5 ° C . The current trajectory of global greenhouse gas emissions does not appear to be consistent with limiting global warming to below 1.5 or 2 ° C . Other mitigation policies have been proposed , some of which are more stringent or modest than the 2 ° C limit . |
815 | Shutdown_of_thermohaline_circulation | Evidence is growing that the comparatively cold zone within the Northern Atlantic could be due to a slowdown of this global ocean water circulation. | Shutdown of thermohaline circulation A shutdown or slowdown of the thermohaline circulation is an effect of global warming on a major ocean circulation . Data from 2010 NASA suggested that the Atlantic Meridional Overturning Circulation has not slowed down , but may have actually sped up slightly in the recent past . However , this has been superseded by a 2015 study that suggests ` that the Gulf Stream has weakened by 15-20 % ' |
2447 | Global_dimming | The main reason behind this mid-century cooling was global dimming due to anthropogenic sulfate aerosol emissions. | Global dimming Global dimming is the gradual reduction in the amount of global direct irradiance at the Earth 's surface that was observed for several decades after the start of systematic measurements in the 1950s . The effect varies by location , but worldwide it has been estimated to be of the order of a 4 % reduction over the three decades from 1960 -- 1990 . However , after discounting an anomaly caused by the eruption of Mount Pinatubo in 1991 , a very slight reversal in the overall trend has been observed . Global dimming is thought to have been caused by an increase in particulates such as sulfate aerosols in the atmosphere due to human action . It has interfered with the hydrological cycle by reducing evaporation and may have reduced rainfall in some areas . Global dimming also creates a cooling effect that may have partially counteracted the effect of greenhouse gases on global warming . |
2552 | Mesozoic | The geologic record provides us with abundant evidence for such perpetual natural climate variability, from icecaps reaching almost to the equator to none at all, even at the poles. | Mesozoic The Mesozoic Era ( -LSB- pronˌmɛsəˈzoʊɪk , _ ˌmiː - , _ - soʊ - -RSB- or -LSB- ˌmɛzəˈzoʊɪk , _ ˌmiː - , _ - soʊ - -RSB- ) is an interval of geological time from about . It is also called the Age of Reptiles , a phrase introduced by the 19th century paleontologist Gideon Mantell who viewed it as dominated by diapsids such as Iguanodon , Megalosaurus , Plesiosaurus and Pterodactylus . This Era is also called from a paleobotanist view the Age of Conifers . Mesozoic means `` middle life '' , deriving from the Greek prefix meso - / μεσο - for `` between '' and zōon / ζῷον meaning `` animal '' or `` living being '' . It is one of three geologic eras of the Phanerozoic Eon , preceded by the Paleozoic ( `` ancient life '' ) and succeeded by the Cenozoic ( `` new life '' ) . The era is subdivided into three major periods : the Triassic , Jurassic , and Cretaceous , which are further subdivided into a number of epochs and stages . The era began in the wake of the Permian -- Triassic extinction event , the largest well-documented mass extinction in Earth 's history , and ended with the Cretaceous -- Paleogene extinction event , another mass extinction which is known for having killed off non-avian dinosaurs , as well as other plant and animal species . The Mesozoic was a time of significant tectonic , climate and evolutionary activity . The era witnessed the gradual rifting of the supercontinent Pangaea into separate landmasses that would eventually move into their current positions . The climate of the Mesozoic was varied , alternating between warming and cooling periods . Overall , however , the Earth was hotter than it is today . Dinosaurs appeared in the Late Triassic and became the dominant terrestrial vertebrates early in the Jurassic , occupying this position for about 135 million years until their demise at the end of the Cretaceous . Birds first appeared in the Jurassic , having evolved from a branch of theropod dinosaurs . The first mammals also appeared during the Mesozoic , but would remain small -- less than 15 kg ( 33 lb ) -- until the Cenozoic . |
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