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Global warming and climate change are terms for 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.〔(【引用サイトリンク】url=http://epa.gov/climatechange/endangerment/myths-facts.html )The U.S. Global Change Research Program, the National Academy of Sciences, and the Intergovernmental Panel on Climate Change (IPCC) have each independently concluded that warming of the climate system in recent decades is 'unequivocal'. This conclusion is not drawn from any one source of data but is based on multiple lines of evidence, including three worldwide temperature datasets showing nearly identical warming trends as well as numerous other independent indicators of global warming (e.g., rising sea levels, shrinking Arctic sea ice).〕 Although the increase of near-surface atmospheric temperature is the measure of global warming often reported in the popular press, most of the additional energy stored in the climate system since 1970 has gone into ocean warming. The remainder has melted ice, and warmed the continents and atmosphere. Many of the observed changes since the 1950s are unprecedented over decades to millennia.〔IPCC, Climate Change 2013: The Physical Science Basis - Summary for Policymakers, Observed Changes in the Climate System, (p. 2 ), in . "Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia."〕 Scientific understanding of global warming is increasing. The Intergovernmental Panel on Climate Change (IPCC) reported in 2014 that scientists were more than 95% certain that global warming is being caused mostly by increasing concentrations of greenhouse gases and other human (anthropogenic) activities.〔 〕 Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further for their lowest emissions scenario using stringent mitigation and for their highest.〔Stocker ''et al.'', (Technical Summary ), in .〕 These findings have been recognized by the national science academies of the major industrialized nations〔(【引用サイトリンク】title=Joint Science Academies' Statement )〕 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.〔 , in 〕〔Solomon ''et al.'', (Technical Summary ), (Section TS.5.3: Regional-Scale Projections ), in .〕 Anticipated effects include warming global temperature, rising sea levels, changing precipitation, and expansion of deserts in the subtropics.〔 〕 Warming is expected to be 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, and heavy snowfall;〔On snowfall: * * * (【引用サイトリンク】title=Does record snowfall disprove global warming? )〕 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 flooding. 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),〔. Most countries in the world are Parties to the United Nations Framework Convention on Climate Change (UNFCCC), which has adopted the target. As of 25 November 2011, there are 195 parties (194 states and 1 regional economic integration organization (the European Union)) to the UNFCCC.〕 whose ultimate objective is to prevent dangerous anthropogenic climate change.〔(【引用サイトリンク】work=The United Nations Framework Convention on Climate Change ), excerpt from the founding international treaty that took force on 21 March 1994.〕 The UNFCCC have adopted a range of policies designed to reduce greenhouse gas emissions〔 〕〔Gupta, S. ''et al''. (13.2 Climate change and other related policies ), in .〕〔 , in (pp.175-186 of PDF) 〕〔 〕 and to assist in adaptation to global warming.〔〔〔Adger, ''et al.'', (Chapter 17: Assessment of adaptation practices, options, constraints and capacity, ) (Executive summary ), in .〕〔(6. Generating the funding needed for mitigation and adaptation (PDF) ), in 〕 Parties to the UNFCCC have agreed that deep cuts in emissions are required,〔 "(...) deep cuts in global greenhouse gas emissions are required according to science, and as documented in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, with a view to reducing global greenhouse gas emissions so as to hold the increase in global average temperature below above preindustrial levels"〕 and that future global warming should be limited to below relative to the pre-industrial level.}} On 12 November 2015, NASA scientists reported that human-made carbon dioxide (CO2) continues to increase above levels not seen in hundreds of thousands of years: currently, about half of the carbon dioxide released from the burning of fossil fuels remains in the atmosphere and is not absorbed by vegetation and the oceans.〔〔〔〔 == Observed temperature changes == (詳細はto 1.06 ) °C in the period 1880 to 2012, based on multiple independently produced datasets. Earth's average surface temperature rose by over the period 1906–2005. The rate of warming almost doubled for the last half of that period (, versus ).〔(【引用サイトリンク】title=Climate Change 2007: Working Group I: The Physical Science Basis )〕 The average temperature of the lower troposphere has increased between per decade since 1979, according to satellite temperature measurements. Climate proxies show the temperature to have been relatively stable over the one or two thousand years before 1850, with regionally varying fluctuations such as the Medieval Warm Period and the Little Ice Age.〔Jansen ''et al.'', (Ch. 6, Palaeoclimate ), (Section 6.6.1.1: What Do Reconstructions Based on Palaeoclimatic Proxies Show? ), (pp. 466–478 ), in .〕 The warming that is evident in the instrumental temperature record is consistent with a wide range of observations, as documented by many independent scientific groups.〔 〕 Examples include sea level rise,〔 〕 widespread melting of snow and land ice,〔 , in 〕 increased heat content of the oceans,〔 increased humidity,〔 and the earlier timing of spring events,〔 , in 〕 e.g., the flowering of plants.〔 , in 〕 The probability that these changes could have occurred by chance is virtually zero.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Global warming」の詳細全文を読む スポンサード リンク
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