Global warming

2013-01-01T18:34:19Z

Hensomm: Just some small changes on minor fact checking

[[Image:NASA-1024x933.jpg|thumb|right|250px|A composite map of [[Antarctica]] showing areas of greatest warming in red. The Wilkins Ice Shelf lies off the peninsula in the top left corner, and shows extensive warming. Overall, Antarctica shows little warming, and many areas to the East (right) are cooling Roberts, Greg. "Antarctic Ice is Growing, Not Melting Away." April 18, 2009. http://www.news.com.au/antarctic-ice-is-growing-not-melting-away/story-0-1225700043191</ref>.]]
Global warming is the rise in the average temperature of Earth's atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth's mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980.[2] Warming of the climate system is unequivocal, and scientists are more than 90% certain that it is primarily caused by increasing concentrations of greenhouse gases produced by human activities such as the burning of fossil fuels and deforestation.[3][4][5][6] These findings are recognized by the national science academies of all major industrialized nations.[7][A]
Climate model projections were summarized in the 2007 Fourth Assessment Report (AR4) by the Intergovernmental Panel on Climate Change (IPCC). They indicated that during the 21st century the global surface temperature is likely to rise a further 1.1 to 2.9 °C (2 to 5.2 °F) for their lowest emissions scenario and 2.4 to 6.4 °C (4.3 to 11.5 °F) for their highest.[8] The ranges of these estimates arise from the use of models with differing sensitivity to greenhouse gas concentrations.[9][10]
According to AR4, warming and related changes will vary from region to region around the globe.[11] The effects of an increase in global temperature include a rise in sea levels and a change in the amount and pattern of precipitation, as well a probable expansion of subtropical deserts.[12] Warming is expected to be strongest in the Arctic and would be associated with the continuing retreat of glaciers, permafrost and sea ice. Other likely effects of the warming include a more frequent occurrence of extreme-weather events including heat waves, droughts and heavy rainfall, 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 loss of habitat from inundation.[13][14]
Proposed policy responses to global warming include mitigation by emissions reduction, adaptation to its effects, and possible future geoengineering. Most countries are parties to the United Nations Framework Convention on Climate Change (UNFCCC),[15] whose ultimate objective is to prevent dangerous anthropogenic (i.e., human-induced) climate change.[16] Parties to the UNFCCC have adopted a range of policies designed to reduce greenhouse gas emissions[17]:10[18][19][20]:9 and to assist in adaptation to global warming.[17]:13[20]:10[21][22] Parties to the UNFCCC have agreed that deep cuts in emissions are required,[23] and that future global warming should be limited to below 2.0 °C (3.6 °F) relative to the pre-industrial level.[23][B] Reports published in 2011 by the United Nations Environment Programme[24] and the International Energy Agency[25] suggest that efforts as of the early 21st century to reduce emissions may be inadequate to meet the UNFCCC's 2 °C target.

==Science of Global Warming==
The Earth's average surface temperature rose by 0.74±0.18 °C over the period 1906–2005. The rate of warming over the last half of that period was almost double that for the period as a whole (0.13±0.03 °C per decade, versus 0.07±0.02 °C per decade). The urban heat island effect is very small, estimated to account for less than 0.002 °C of warming per decade since 1900.[27] Temperatures in the lower troposphere have increased between 0.13 and 0.22 °C (0.22 and 0.4 °F) 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.[28]
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.[29] Examples include sea level rise (water expands as it warms),[30] widespread melting of snow and ice,[31] increased heat content of the oceans,[29] increased humidity,[29] and the earlier timing of spring events,[32] e.g., the flowering of plants.[33] The probability that these changes could have occurred by chance is virtually zero.[29]
Recent estimates by NASA's Goddard Institute for Space Studies (GISS) and the National Climatic Data Center show that 2005 and 2010 tied for the planet's warmest year since reliable, widespread instrumental measurements became available in the late 19th century, exceeding 1998 by a few hundredths of a degree.[34][35][36] Estimates by the Climatic Research Unit (CRU) show 2005 as the second warmest year, behind 1998 with 2003 and 2010 tied for third warmest year, however, "the error estimate for individual years ... is at least ten times larger than the differences between these three years."[37] The World Meteorological Organization (WMO) statement on the status of the global climate in 2010 explains that, "The 2010 nominal value of +0.53 °C ranks just ahead of those of 2005 (+0.52 °C) and 1998 (+0.51 °C), although the differences between the three years are not statistically significant..."[38]

NOAA graph of Global Annual Temperature Anomalies 1950–2011, showing the El Niño-Southern Oscillation
Temperatures in 1998 were unusually warm because global temperatures are affected by the El Niño-Southern Oscillation (ENSO), and the strongest El Niño in the past century occurred during that year.[39] Global temperature is subject to short-term fluctuations that overlay long term trends and can temporarily mask them. The relative stability in temperature from 2002 to 2009 is consistent with such an episode.[40][41] 2010 was also an El Niño year. On the low swing of the oscillation, 2011 as an La Niña year was cooler but it was still the 11th warmest year since records began in 1880. Of the 13 warmest years since 1880, 11 were the years from 2001 to 2011. Over the more recent record, 2011 was the warmest La Niña year in the period from 1950 to 2011, and was close to 1997 which was not at the lowest point of the cycle.[42]
Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 °C per decade against 0.13 °C per decade).[43] Ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation.[44] The northern hemisphere warms faster than the southern hemisphere because it has more land and because it has extensive areas of seasonal snow and sea-ice cover subject to ice-albedo feedback. Although more greenhouse gases are emitted in the Northern than Southern Hemisphere this does not contribute to the difference in warming because the major greenhouse gases persist long enough to mix between hemispheres.[45]
The thermal inertia of the oceans and slow responses of other indirect effects mean that climate can take centuries or longer to adjust to changes in forcing. Climate commitment studies indicate that even if greenhouse gases were stabilized at 2000 levels, a further warming of about 0.5 °C (0.9 °F) would still occur.[46]

===Green House Gas===
The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in the atmosphere warm a planet's lower atmosphere and surface. It was proposed by Joseph Fourier in 1824 and was first investigated quantitatively by Svante Arrhenius in 1896.[52]

Annual world greenhouse gas emissions, in 2005, by sector.

Bubble diagram showing the share of global cumulative energy-related carbon dioxide emissions for major emitters between 1890-2007.[53]
Naturally occurring amounts of greenhouse gases have a mean warming effect of about 33 °C (59 °F).[54][C] The major greenhouse gases are water vapor, which causes about 36–70% of the greenhouse effect; carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone (O3), which causes 3–7%.[55][56][57] Clouds also affect the radiation balance through cloud forcings similar to greenhouse gases.
Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs and nitrous oxide. The concentrations of CO2 and methane have increased by 36% and 148% respectively since 1750.[58] These levels are much higher than at any time during the last 800,000 years, the period for which reliable data has been extracted from ice cores.[59][60][61][62] Less direct geological evidence indicates that CO2 values higher than this were last seen about 20 million years ago.[63] Fossil fuel burning has produced about three-quarters of the increase in CO2 from human activity over the past 20 years. The rest of this increase is caused mostly by changes in land-use, particularly deforestation.[64]
Over the last three decades of the 20th century, gross domestic product per capita and population growth were the main drivers of increases in greenhouse gas emissions.[65] CO2 emissions are continuing to rise due to the burning of fossil fuels and land-use change.[66][67]:71 Emissions can be attributed to different regions, e.g., see the figure opposite. Attribution of emissions due to land-use change is a controversial issue.[68][69]:289
Emissions scenarios, estimates of changes in future emission levels of greenhouse gases, have been projected that depend upon uncertain economic, sociological, technological, and natural developments.[70] In most scenarios, emissions continue to rise over the century, while in a few, emissions are reduced.[71][72] Fossil fuel reserves are abundant, and will not limit carbon emissions in the 21st century.[73] Emission scenarios, combined with modelling of the carbon cycle, have been used to produce estimates of how atmospheric concentrations of greenhouse gases might change in the future. Using the six IPCC SRES "marker" scenarios, models suggest that by the year 2100, the atmospheric concentration of CO2 could range between 541 and 970 ppm.[74] This is an increase of 90–250% above the concentration in the year 1750.
The popular media and the public often confuse global warming with ozone depletion, i.e., the destruction of stratospheric ozone by chlorofluorocarbons.[75][76] Although there are a few areas of linkage, the relationship between the two is not strong. Reduced stratospheric ozone has had a slight cooling influence on surface temperatures, while increased tropospheric ozone has had a somewhat larger warming effect.[77]

==References==
IEA (2009), World Energy Outlook 2009, Paris, France: International Energy Agency (IEA), ISBN 978-92-64-06130-9
IPCC AR4 SYR (2007), Core Writing Team; Pachauri, R.K; and Reisinger, A., ed., Climate Change 2007: Synthesis Report, Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC, ISBN 92-9169-122-4
IPCC AR4 WG1 (2007), Solomon, S.; Qin, D.; Manning, M.; Chen, Z.; Marquis, M.; Averyt, K.B.; Tignor, M.; and Miller, H.L., ed., Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 978-0-521-88009-1 (pb: 978-0-521-70596-7)
IPCC AR4 WG2 (2007), Parry, M.L.; Canziani, O.F.; Palutikof, J.P.; van der Linden, P.J.; and Hanson, C.E., ed., Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 978-0-521-88010-7 (pb: 978-0-521-70597-4)
IPCC AR4 WG3 (2007), Metz, B.; Davidson, O.R.; Bosch, P.R.; Dave, R.; and Meyer, L.A., ed., Climate Change 2007: Mitigation of Climate Change, Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 978-0-521-88011-4 (pb: 978-0-521-70598-1)
IPCC SAR SYR (1996), Climate Change 1995: A report of the Intergovernmental Panel on Climate Change, Second Assessment Report of the Intergovernmental Panel on Climate Change, IPCC pdf. The "Full Report", consisting of "The IPCC Second Assessment Synthesis of Scientific-Technical Information Relevant to Interpreting Article 2 of the UN Framework Convention on Climate Change" and the Summaries for Policymakers of the three Working Groups.
IPCC SAR WG3 (1996), Bruce, J.P.; Lee, H.; and Haites, E.F., ed., Climate Change 1995: Economic and Social Dimensions of Climate Change, Contribution of Working Group III to the Second Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 0-521-56051-9 (pb: 0-521-56854-4) pdf.
IPCC TAR WG1 (2001), Houghton, J.T.; Ding, Y.; Griggs, D.J.; Noguer, M.; van der Linden, P.J.; Dai, X.; Maskell, K.; and Johnson, C.A., ed., Climate Change 2001: The Scientific Basis, Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 0-521-80767-0 (pb: 0-521-01495-6)
IPCC TAR WG2 (2001), McCarthy, J. J.; Canziani, O. F.; Leary, N. A.; Dokken, D. J.; and White, K. S., ed., Climate Change 2001: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 0-521-80768-9 (pb: 0-521-01500-6)
IPCC TAR WG3 (2001), Metz, B.; Davidson, O.; Swart, R.; and Pan, J., ed., Climate Change 2001: Mitigation, Contribution of Working Group III to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 0-521-80769-7 (pb: 0-521-01502-2)
IPCC TAR SYR (2001), Watson, R. T.; and the Core Writing Team, ed., Climate Change 2001: Synthesis Report, Contribution of Working Groups I, II, and III to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 0-521-80770-0 (pb: 0-521-01507-3)
National Research Council (2010), America's Climate Choices: Panel on Advancing the Science of Climate Change;, Washington, D.C.: The National Academies Press, ISBN 0-309-14588-0
This article incorporates public domain material from the US Global Change Research Program (USGCRP) document: USGCRP (2009), Karl, T.R.; Melillo. J.; Peterson, T.; Hassol, S.J., ed., Global Climate Change Impacts in the United States, Cambridge University Press, ISBN 978-0-521-14407-0. Public-domain status of this report can be found on p.4 of PDF
US NRC (2008), Understanding and responding to climate change: Highlights of National Academies Reports, 2008 edition, produced by the US National Research Council (US NRC), Washington, D.C., USA: National Academy of Sciences
US NRC (2012), Climate Change: Evidence, Impacts, and Choices, US National Research Council (US NRC). Also available as PDF
Further reading

Association of British Insurers (2005–06) (PDF). Financial Risks of Climate Change.
Ammann, Caspar; et al. (2007). "Solar influence on climate during the past millennium: Results from transient simulations with the NCAR Climate Simulation Model" (PDF). Proceedings of the National Academy of Sciences of the United States of America 104 (10): 3713–3718. Bibcode 2007PNAS..104.3713A. doi:10.1073/pnas.0605064103. PMC 1810336. PMID 17360418. "Simulations with only natural forcing components included yield an early 20th century peak warming of ≈0.2 °C (≈1950 AD), which is reduced to about half by the end of the century because of increased volcanism"
Barnett, Tim P.; Adam, JC; Lettenmaier, DP; Adam, J. C.; Lettenmaier, D. P. (17 November 2005). "Potential impacts of a warming climate on water availability in snow-dominated regions" (abstract). Nature 438 (7066): 303–309. Bibcode 2005Natur.438..303B. doi:10.1038/nature04141. PMID 16292301.
Behrenfeld, Michael J.; O'malley, RT; Siegel, DA; Mcclain, CR; Sarmiento, JL; Feldman, GC; Milligan, AJ; Falkowski, PG et al.; et al. (7 December 2006). "Climate-driven trends in contemporary ocean productivity" (PDF). Nature 444 (7120): 752–755. Bibcode 2006Natur.444..752B. doi:10.1038/nature05317. PMID 17151666.
Choi, Onelack; Fisher, Ann (May 2005). "The Impacts of Socioeconomic Development and Climate Change on Severe Weather Catastrophe Losses: Mid-Atlantic Region (MAR) and the U.S". Climate Change 58 (1–2): 149–170. doi:10.1023/A:1023459216609.
Dyurgerov, Mark B.; Meier, Mark F. (2005) (PDF). Glaciers and the Changing Earth System: a 2004 Snapshot. Institute of Arctic and Alpine Research Occasional Paper #58. ISSN 0069-6145.
Emanuel, Kerry A. (4 August 2005). "Increasing destructiveness of tropical cyclones over the past 30 years" (PDF). Nature 436 (7051): 686–688. Bibcode 2005Natur.436..686E. doi:10.1038/nature03906. PMID 16056221.
Hansen, James; et al. (3 June 2005). "Earth's Energy Imbalance: Confirmation and Implications" (PDF). Science 308 (5727): 1431–1435. Bibcode 2005Sci...308.1431H. doi:10.1126/science.1110252. PMID 15860591.
Hinrichs, Kai-Uwe; Hmelo, Laura R.; Sylva, Sean P. (21 February 2003). "Molecular Fossil Record of Elevated Methane Levels in Late Pleistocene Coastal Waters". Science 299 (5610): 1214–1217. Bibcode 2003Sci...299.1214H. doi:10.1126/science.1079601. PMID 12595688.
Hirsch, Tim (11 January 2006). "Plants revealed as methane source". BBC.
Hoyt, Douglas V.; Schatten, Kenneth H. (1993–11). "A discussion of plausible solar irradiance variations, 1700–1992". Journal of Geophysical Research 98 (A11): 18,895–18,906. Bibcode 1993JGR....9818895H. doi:10.1029/93JA01944.
Karnaukhov, A. V. (2001). "Role of the Biosphere in the Formation of the Earth's Climate: The Greenhouse Catastrophe" (PDF). Biophysics 46 (6).
Kenneth, James P.; et al. (14 February 2003). Methane Hydrates in Quaternary Climate Change: The Clathrate Gun Hypothesis. American Geophysical Union.
Keppler, Frank; et al. (18 January 2006). "Global Warming – The Blame Is not with the Plants". Max Planck Society.
Lean, Judith L.; Wang, Y.M.; Sheeley, N.R. (2002–12). "The effect of increasing solar activity on the Sun's total and open magnetic flux during multiple cycles: Implications for solar forcing of climate" (abstract). Geophysical Research Letters 29 (24): 2224. Bibcode 2002GeoRL..29x..77L. doi:10.1029/2002GL015880.
Lerner, K. Lee; Lerner, K. Lee; Wilmoth, Brenda (26 July 2006). Environmental issues: essential primary sources. Thomson Gale. ISBN 1-4144-0625-8.
McKibben, Bill (2011). The Global Warming Reader. OR Books. ISBN 978-1-935928-36-2.
Muscheler, Raimund, R; Joos, F; Müller, SA; Snowball, I; et al. (28 July 2005). "Climate: How unusual is today's solar activity?" (PDF). Nature 436 (7012): 1084–1087. Bibcode 2005Natur.436E...3M. doi:10.1038/nature04045. PMID 16049429.
Oerlemans, J. (29 April 2005). "Extracting a Climate Signal from 169 Glacier Records" (PDF). Science 308 (5722): 675–677. Bibcode 2005Sci...308..675O. doi:10.1126/science.1107046. PMID 15746388.
Purse, Bethan V.; Mellor, PS; Rogers, DJ; Samuel, AR; Mertens, PP; Baylis, M; et al. (February 2005). "Climate change and the recent emergence of bluetongue in Europe" (abstract). Nature Reviews Microbiology 3 (2): 171–181. doi:10.1038/nrmicro1090. PMID 15685226.
Revkin, Andrew C (5 November 2005). "Rise in Gases Unmatched by a History in Ancient Ice". The New York Times.
Royal Society (2005). "Joint science academies' statement: Global response to climate change". Retrieved 19 April 2009.
Ruddiman, William F. (15 December 2005). Earth's Climate Past and Future. New York: Princeton University Press. ISBN 0-7167-3741-8.
Ruddiman, William F. (1 August 2005). Plows, Plagues, and Petroleum: How Humans Took Control of Climate. New Jersey: Princeton University Press. ISBN 0-691-12164-8.
Solanki, Sami K.; Usoskin, IG; Kromer, B; Schüssler, M; Beer, J; et al. (23 October 2004). "Unusual activity of the Sun during recent decades compared to the previous 11,000 years" (PDF). Nature 431 (7012): 1084–1087. Bibcode 2004Natur.431.1084S. doi:10.1038/nature02995. PMID 15510145.
Solanki, Sami K.; et al. (28 July 2005). "Climate: How unusual is today's solar activity? (Reply)" (PDF). Nature 436 (7050): E4–E5. Bibcode 2005Natur.436E...4S. doi:10.1038/nature04046.
Sowers, Todd (10 February 2006). "Late Quaternary Atmospheric CH4 Isotope Record Suggests Marine Clathrates Are Stable". Science 311 (5762): 838–840. Bibcode 2006Sci...311..838S. doi:10.1126/science.1121235. PMID 16469923.
Svensmark, Henrik; et al. (8 February 2007). "Experimental evidence for the role of ions in particle nucleation under atmospheric conditions". Proceedings of the Royal Society A (FirstCite Early Online Publishing) 463 (2078): 385–396. Bibcode 2007RSPSA.463..385S. doi:10.1098/rspa.2006.1773.(online version requires registration)
Walter, K. M.; Zimov, SA; Chanton, JP; Verbyla, D; Chapin Fs, 3rd; et al. (7 September 2006). "Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming". Nature 443 (7107): 71–75. Bibcode 2006Natur.443...71W. doi:10.1038/nature05040. PMID 16957728.
Wang, Y.-M.; Lean, J.L.; Sheeley, N.R. (20 May 2005). "Modeling the sun's magnetic field and irradiance since 1713" (PDF). Astrophysical Journal 625 (1): 522–538. Bibcode 2005ApJ...625..522W. doi:10.1086/429689.

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