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{{multiple image|align=right|direction=vertical|width=220|image1=Instrumental Temperature Record.png|caption1=Global mean surface temperature difference relative to the 1961–1990 average|image2=Satellite Temperatures.png|caption2=Comparison of ground based (blue) and satellite based (red: [[University of Alabama in Huntsville|UAH]]; green: [[Remote Sensing Systems|RSS]]) records of temperature variations since 1979. Trends plotted since January 1982.|image3=GISS temperature 2000-09 lrg.png|image4=GISS temperature palette.png|caption4=Mean surface temperature change for the period 2000 to 2009 relative to the average temperatures from 1951 to 1980.<ref>[http://earthobservatory.nasa.gov/IOTD/view.php?id=42392 2009 Ends Warmest Decade on Record]. [[NASA]] Earth Observatory Image of the Day, January 22, 2010.</ref>}}
{{multiple image|align=right|direction=vertical|width=220|image1=Instrumental Temperature Record.png|caption1=Global mean surface temperature difference relative to the 1961–1990 average|image2=Satellite Temperatures.png|caption2=Comparison of ground based (blue) and satellite based (red: [[University of Alabama in Huntsville|UAH]]; green: [[Remote Sensing Systems|RSS]]) records of temperature variations since 1979. Trends plotted since January 1982.|image3=GISS temperature 2000-09 lrg.png|image4=GISS temperature palette.png|caption4=Mean surface temperature change for the period 2000 to 2009 relative to the average temperatures from 1951 to 1980.<ref>[http://earthobservatory.nasa.gov/IOTD/view.php?id=42392 2009 Ends Warmest Decade on Record]. [[NASA]] Earth Observatory Image of the Day, January 22, 2010.</ref>}}


'''Global warming''' is the [[Instrumental temperature record|average]] warming of the [[Earth]]'s near-surface air and oceans since the 1950s and its expected continuation. A recent report says that the world's surface warmed 0.74&nbsp;±&nbsp;0.18&nbsp;°[[Celsius|C]] (1.33&nbsp;±&nbsp;0.32&nbsp;°[[Fahrenheit|F]]) sometime between 1900 AD - 2000 AD.<ref name="grida7"/>{{Cref2|A}} Most of the observed warmth since the [[attribution of recent climate change|1950s was caused]] by the rising levels of [[greenhouse gas]]es, which results from everyday actions [[anthropogenic|made by people]] such as [[deforestation|destroying forests]] and the burning of gasoline, fuel or diesel for cars, trucks, planes, cargo ships, and factories just to name a few.<ref>{{cite web|title=Understanding and Responding to Climate Change|url=http://americasclimatechoices.org/climate_change_2008_final.pdf|publisher=[[United States National Academy of Sciences]]|accessdate=30 May 2010|date=2008|quote=Most scientists agree that the warming in recent decades has been caused primarily by human activities that have increased the amount of greenhouse gases in the atmosphere.}}</ref>
'''Global warming''' is the increase in the [[Instrumental temperature record|average temperature]] of [[Earth]]'s near-surface air and oceans since the mid-[[20th century]] and its projected continuation. According to a report by the [[Intergovernmental Panel on Climate Change]] (IPCC) global surface temperature increased 0.74&nbsp;±&nbsp;0.18&nbsp;°[[Celsius|C]] (1.33&nbsp;±&nbsp;0.32&nbsp;°[[Fahrenheit|F]]) between the start and the end of the 20th century.<ref name="grida7"/>{{Cref2|A}} The climatology literature uniformly states that most of the observed temperature increase since the middle of the 20th century was [[attribution of recent climate change|caused]] by increasing concentrations of [[greenhouse gas]]es, which results from [[anthropogenic|human activity]] such as [[fossil fuel]] burning and [[deforestation]].<ref>{{cite web|title=Understanding and Responding to Climate Change|url=http://americasclimatechoices.org/climate_change_2008_final.pdf|publisher=[[United States National Academy of Sciences]]|accessdate=30 May 2010|date=2008|quote=Most scientists agree that the warming in recent decades has been caused primarily by human activities that have increased the amount of greenhouse gases in the atmosphere.}}</ref>


[[Climate model]] projections indicate that the global [[surface temperature]] is likely to rise a further {{nowrap|1.1 to 6.4&nbsp;°C}} {{nowrap|(2.0 to 11.5&nbsp;°F)}} during the 21st century.<ref name="grida7"/> The uncertainty in this estimate arises from the use of models with differing [[climate sensitivity|sensitivity to greenhouse gas concentrations]] and the use of differing [[Special Report on Emissions Scenarios|estimates of future greenhouse gas emissions]].<ref name="grida7"/> An increase in global temperature will cause [[sea level rise|sea levels to rise]] and will change the amount and pattern of [[precipitation (meteorology)|precipitation]], probably including expansion of [[Subtropics|subtropical]] [[desert]]s.<ref name="Lu-2007"/> Warming is expected to be [[Arctic shrinkage|strongest in the]] [[Arctic]] and would be associated with continuing [[retreat of glaciers since 1850|retreat of glaciers]], [[permafrost]] and [[sea ice]]. Other likely effects include changes in the frequency and intensity of [[extreme weather]] events, [[extinction risk from climate change|species extinctions]], and changes in [[agricultural yield]]s. Warming and related changes will vary from region to region around the globe, though the nature of these regional variations is uncertain.<ref name="IPCCSynthesisReport2007" />
[[Climate model]] projections summarized in the latest IPCC report indicate that the global [[surface temperature]] is likely to rise a further {{nowrap|1.1 to 6.4&nbsp;°C}} {{nowrap|(2.0 to 11.5&nbsp;°F)}} during the 21st century.<ref name="grida7"/> The uncertainty in this estimate arises from the use of models with differing [[climate sensitivity|sensitivity to greenhouse gas concentrations]] and the use of differing [[Special Report on Emissions Scenarios|estimates of future greenhouse gas emissions]].
An increase in global temperature will cause [[sea level rise|sea levels to rise]] and will change the amount and pattern of [[precipitation (meteorology)|precipitation]], probably including expansion of [[Subtropics|subtropical]] [[desert]]s.<ref name="Lu-2007"/> Warming is expected to be [[Arctic shrinkage|strongest in the Arctic]] and would be associated with continuing [[retreat of glaciers since 1850|retreat of glaciers]], [[permafrost]] and [[sea ice]]. Other likely effects include changes in the frequency and intensity of [[extreme weather]] events, [[extinction risk from climate change|species extinctions]], and changes in [[agricultural yield]]s. Warming and related changes will vary from region to region around the globe, though the nature of these regional variations is uncertain.<ref name="IPCCSynthesisReport2007" />


There is no longer any scholarly debate in regards to the legitmacy of human-caused global warming. The scientific consensus states that this phenomenon is real and happening today.<ref>Union of Concerned Scientists, 2009, [http://www.ucsusa.org/ssi/climate-change/scientific-consensus-on.html "Scientific Consensus on Global Warming"]</ref><ref>{{Citation| last = Oreskes| first = Naomi| author-link = Naomi Oreskes| title = BEYOND THE IVORY TOWER: The Scientific Consensus on Climate Change| journal = Science| volume = 306| pages = 1686| date = December 2004| url =http://www.sciencemag.org/cgi/content/full/306/5702/1686| year = 2004 | quote=Such statements suggest that there might be substantive disagreement in the scientific community about the reality of anthropogenic climate change. This is not the case. [...] Politicians, economists, journalists, and others may have the impression of confusion, disagreement, or discord among climate scientists, but that impression is incorrect. }}</ref> Nevertheless, [[Politics of global warming|political]] and [[global warming controversy|public]] debate continues.
The overwhelming scientific consensus is that human-made global warming is real.<ref>{{Citation| last = Oreskes| first = Naomi| author-link = Naomi Oreskes| title = BEYOND THE IVORY TOWER: The Scientific Consensus on Climate Change| journal = Science| volume = 306| pages = 1686| date = December 2004| url =http://www.sciencemag.org/cgi/content/full/306/5702/1686| year = 2004 | quote=Such statements suggest that there might be substantive disagreement in the scientific community about the reality of anthropogenic climate change. This is not the case. [...] Politicians, economists, journalists, and others may have the impression of confusion, disagreement, or discord among climate scientists, but that impression is incorrect. }}</ref><ref>Union of Concerned Scientists, 2009, [http://www.ucsusa.org/ssi/climate-change/scientific-consensus-on.html "Scientific Consensus on Global Warming"]</ref> Nevertheless, [[Politics of global warming|political]] and [[global warming controversy|public]] debate continues. Some oil companies have funded [[public relations]] campaigns and deeply flawed research studies<ref>{{Citation| last = Sanchez| first = Irene| title = Warming Study Draws Fire Harvard scientists accused of politicizing research| newspaper = The Harvard Crimson| location = Cambridge| date = 12 September 2003| url =http://www.thecrimson.com/article/2003/9/12/warming-study-draws-fire-a-study/}}</ref> intended to discredit the [[Scientific opinion on climate change|global scientific consensus]].<ref>{{Citation| last = Vidal| first = John| title = US oil company donated millions to climate sceptic groups, says Greenpeace| newspaper = The Guardian| location = London| date = 30 March 2010| url =http://www.guardian.co.uk/environment/2010/mar/30/us-oil-donated-millions-climate-sceptics }}</ref><ref>{{Citation| last = Sample| first = Ian| title = Scientists offered cash to dispute climate study| newspaper = The Guardian| location = London| date = 2 February 2007| url= http://www.guardian.co.uk/environment/2007/feb/02/frontpagenews.climatechange}}</ref>


==Temperature changes==
==Temperature changes==
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|accessdate=2010-04-17}}</ref> The most common measure of global warming is the trend in globally averaged temperature near the Earth's surface. Expressed as a [[linear]] trend, this temperature rose by 0.74&nbsp;±&nbsp;0.18&nbsp;°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&nbsp;±&nbsp;0.03&nbsp;°C per decade, versus 0.07&nbsp;°C ± 0.02&nbsp;°C per decade). The [[urban heat island]] effect is estimated to account for about 0.002&nbsp;°C of warming per decade since 1900.<ref>{{Cite book|last=Trenberth|first=Kevin E.|coauthors=''et al.''|title=IPCC Fourth Assessment Report|url=http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf|format=PDF|year=2007|publisher=Cambridge University Press|location=Cambridge, United Kingdom and New York, NY, USA|page=244|chapter=Chapter 3: Observations: Surface and Atmospheric Climate Change|chapterurl=http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter3.pdf}}</ref> Temperatures in the lower [[troposphere]] have increased between 0.13 and 0.22&nbsp;°C (0.22 and 0.4&nbsp;°F) per decade since 1979, according to [[satellite temperature measurements]]. Temperature is believed to have been relatively stable over the [[Temperature record of the past 1000 years|one or two thousand years]] before 1850, with regionally varying fluctuations such as the [[Medieval Warm Period]] and the [[Little Ice Age]].<ref>{{cite book |last1= Jansen |first1= E., J. Overpeck |first2= K.R. |last2= Briffa |first3= J.-C. |last3=Duplessy |first4= F. |last4=Joos|first5=V. |last5=Masson-Delmotte|first6=D. |last6=Olago|first7=B. |last7=Otto-Bliesner|first8=W.R. |last8=Peltier|first9=S. |last9=Rahmstorf|first10= R. |last10=Ramesh|first11=D. |last11=Raynaud |first12=D. |last12=Rind|first13=O. |last13=Solomina|first15=R. |last14=Villalba |first16=D. |last15=Zhang |editor1-last=Solomon |editor1-first= S. |editor2-first= D. |editor2-last= Qin |editor3-first=M. |editor3-last= Manning |editor3-first=Z. |editor4-last= Chen |editor4-first=M. |editor5-last= Marquis |editor6-first=K.B. |editor6-last= Averyt |editor7-first=M. |editor7-last= Tignor |editor8-first=H.L. |editor8-last= Miller |title= Climate Change 2007: The Physical Science Basis : contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change |url= http://www.worldcat.org/title/climate-change-2007-the-physical-science-basis-contribution-of-working-group-i-to-the-fourth-assessment-report-of-the-intergovernmental-panel-on-climate-change/oclc/132298563 |series= [[IPCC Fourth Assessment Report]] |date= 2007-02-11 |publisher= Cambridge University Press |location= Cambridge and New York |isbn= 978-0521705967 |oclc= 132298563 |pages= 466-478 |chapter= Palaeoclimate |chapterurl= http://www.ipcc-wg1.unibe.ch/publications/wg1-ar4/ar4-wg1-chapter6.pdf }} </ref>
|accessdate=2010-04-17}}</ref> The most common measure of global warming is the trend in globally averaged temperature near the Earth's surface. Expressed as a [[linear]] trend, this temperature rose by 0.74&nbsp;±&nbsp;0.18&nbsp;°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&nbsp;±&nbsp;0.03&nbsp;°C per decade, versus 0.07&nbsp;°C ± 0.02&nbsp;°C per decade). The [[urban heat island]] effect is estimated to account for about 0.002&nbsp;°C of warming per decade since 1900.<ref>{{Cite book|last=Trenberth|first=Kevin E.|coauthors=''et al.''|title=IPCC Fourth Assessment Report|url=http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf|format=PDF|year=2007|publisher=Cambridge University Press|location=Cambridge, United Kingdom and New York, NY, USA|page=244|chapter=Chapter 3: Observations: Surface and Atmospheric Climate Change|chapterurl=http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter3.pdf}}</ref> Temperatures in the lower [[troposphere]] have increased between 0.13 and 0.22&nbsp;°C (0.22 and 0.4&nbsp;°F) per decade since 1979, according to [[satellite temperature measurements]]. Temperature is believed to have been relatively stable over the [[Temperature record of the past 1000 years|one or two thousand years]] before 1850, with regionally varying fluctuations such as the [[Medieval Warm Period]] and the [[Little Ice Age]].<ref>{{cite book |last1= Jansen |first1= E., J. Overpeck |first2= K.R. |last2= Briffa |first3= J.-C. |last3=Duplessy |first4= F. |last4=Joos|first5=V. |last5=Masson-Delmotte|first6=D. |last6=Olago|first7=B. |last7=Otto-Bliesner|first8=W.R. |last8=Peltier|first9=S. |last9=Rahmstorf|first10= R. |last10=Ramesh|first11=D. |last11=Raynaud |first12=D. |last12=Rind|first13=O. |last13=Solomina|first15=R. |last14=Villalba |first16=D. |last15=Zhang |editor1-last=Solomon |editor1-first= S. |editor2-first= D. |editor2-last= Qin |editor3-first=M. |editor3-last= Manning |editor3-first=Z. |editor4-last= Chen |editor4-first=M. |editor5-last= Marquis |editor6-first=K.B. |editor6-last= Averyt |editor7-first=M. |editor7-last= Tignor |editor8-first=H.L. |editor8-last= Miller |title= Climate Change 2007: The Physical Science Basis : contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change |url= http://www.worldcat.org/title/climate-change-2007-the-physical-science-basis-contribution-of-working-group-i-to-the-fourth-assessment-report-of-the-intergovernmental-panel-on-climate-change/oclc/132298563 |series= [[IPCC Fourth Assessment Report]] |date= 2007-02-11 |publisher= Cambridge University Press |location= Cambridge and New York |isbn= 978-0521705967 |oclc= 132298563 |pages= 466-478 |chapter= Palaeoclimate |chapterurl= http://www.ipcc-wg1.unibe.ch/publications/wg1-ar4/ar4-wg1-chapter6.pdf }} </ref>


Estimates by [[NASA]]'s [[Goddard Institute for Space Studies]] and the [[National Climatic Data Center]] show that 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree.<ref>{{Cite web|url=http://data.giss.nasa.gov/gistemp/2005/|last=Hansen|first=James E.|authorlink=James E. Hansen|coauthors=''et al.''|title=Goddard Institute for Space Studies, GISS Surface Temperature Analysis|accessdate=2007-01-17|date=2006-01-12|publisher=NASA Goddard Institute for Space Studies}}</ref><ref>{{Cite web|url=http://www.ncdc.noaa.gov/sotc/?report=global&year=2009&month=13|last=|first=|authorlink=|coauthors=|title=NOAA/NCDC 2009 climate|accessdate=2010-02-15|date=|publisher=}}</ref> Estimates prepared by the [[World Meteorological Organization]] and the [[Climatic Research Unit]] show 2005 as the second warmest year, behind 1998.<ref>{{Cite web|url=http://www.cru.uea.ac.uk/cru/press/2005-12-WMO.pdf|title=Global Temperature for 2005: second warmest year on record|accessdate=2007-04-13|date=2005-12-15|publisher=Climatic Research Unit, School of Environmental Sciences, University of East Anglia|format=PDF}}</ref><ref>{{Cite web|url=http://www.wmo.int/pages/prog/wcp/wcdmp/statement/documents/WMO998_E.pdf|format=PDF|title=WMO statement on the status of the global climate in 2005|accessdate=2009-04-24|date=2005-12-15|publisher=World Meteorological Organization}}</ref> Temperatures in 1998 were unusually warm because the strongest [[El Niño-Southern Oscillation|El Niño]] in the past century occurred during that year.<ref name="Changnon2000">{{Cite book|title=El Niño, 1997–1998: The Climate Event of the Century|last=Changnon|first=Stanley A.|coauthors=Bell, Gerald D.|year=2000|publisher=Oxford University Press|location=London|isbn=0195135520}}</ref> Global temperature is subject to short-term fluctuations that can temporarily mask long-term trends. The relative stability in temperature from 2002 to 2009 is consistent with such an episode.<ref>{{Cite journal|url=http://www.metoffice.gov.uk/corporate/pressoffice/2009/global_temperatures_09.pdf|title=Do Global Temperature Trends Over the Last Decade Falsify Climate Predictions? [in "State of the Climate in 2008"]|first=J.|last=Knight|first2=J.J.|last2=Kenney|first3=C.|last3=Folland|first4=G.|last4=Harris|first5=G.S.|last5=Jones|first6=M.|last6=Palmer|first7=D.|last7=Parker|first8=A.|last8=Scaife|first9=P.|last9=Stott|work=Bull.Amer.Meteor.Soc.|volume=90|issue=8|pages=S75–S79|date=August 2009|format=PDF|accessdate=2009-09-08}}</ref><ref>{{Cite book|title=Global temperature slowdown&nbsp;— not an end to climate change|publisher=UK Met Office|url=http://www.metoffice.gov.uk/climatechange/policymakers/policy/slowdown.html|accessdate=2009-09-08}}</ref>
Estimates by [[NASA]]'s [[Goddard Institute for Space Studies]] and the [[National Climatic Data Center]] show that 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree.<ref>{{Cite web|url=http://data.giss.nasa.gov/gistemp/2005/|last=Hansen|first=James E.|authorlink=James E. Hansen|coauthors=''et al.''|title=Goddard Institute for Space Studies, GISS Surface Temperature Analysis|accessdate=2007-01-17|date=2006-01-12|publisher=NASA Goddard Institute for Space Studies}}</ref><ref>{{Cite web|url=http://www.ncdc.noaa.gov/sotc/?report=global&year=2009&month=13|last=|first=|authorlink=|coauthors=|title=NOAA/NCDC 2009 climate|accessdate=2010-02-15|date=|publisher=}}</ref> Estimates prepared by the [[World Meteorological Organization]] and the [[Climatic Research Unit]] show 2005 as the second warmest year, behind 1998.<ref>{{Cite web|url=http://www.cru.uea.ac.uk/cru/press/2005-12-WMO.pdf|title=Global Temperature for 2005: second warmest year on record|accessdate=2007-04-13|date=2005-12-15|publisher=Climatic Research Unit, School of Environmental Sciences, University of East Anglia|format=PDF}}</ref><ref>{{Cite web|url=http://www.wmo.int/pages/prog/wcp/wcdmp/statement/documents/WMO998_E.pdf|format=PDF|title=WMO statement on the status of the global climate in 2005|accessdate=2009-04-24|date=2005-12-15|publisher=World Meteorological Organization}}</ref> Temperatures in 1998 were unusually warm because the strongest [[El Niño-Southern Oscillation|El Niño]] in the past century occurred during that year.<ref name="Changnon2000">{{Cite book|title=El Niño, 1997–1998: The Climate Event of the Century|last=Changnon|first=Stanley A.|coauthors=Bell, Gerald D.|year=2000|publisher=Oxford University Press|location=London|isbn=0195135520}}</ref> 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.<ref>{{Cite journal|url=http://www.metoffice.gov.uk/corporate/pressoffice/2009/global_temperatures_09.pdf|title=Do Global Temperature Trends Over the Last Decade Falsify Climate Predictions? [in "State of the Climate in 2008"]|first=J.|last=Knight|first2=J.J.|last2=Kenney|first3=C.|last3=Folland|first4=G.|last4=Harris|first5=G.S.|last5=Jones|first6=M.|last6=Palmer|first7=D.|last7=Parker|first8=A.|last8=Scaife|first9=P.|last9=Stott|work=Bull.Amer.Meteor.Soc.|volume=90|issue=8|pages=S75–S79|date=August 2009|format=PDF|accessdate=2009-09-08}}</ref><ref>{{Cite book|title=Global temperature slowdown&nbsp;— not an end to climate change|publisher=UK Met Office|url=http://www.metoffice.gov.uk/climatechange/policymakers/policy/slowdown.html|accessdate=2009-09-08}}</ref>


Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25&nbsp;°C per decade against 0.13&nbsp;°C per decade).<ref>{{Cite web|url=http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter3.pdf|format=PDF|title=IPCC Fourth Assessment Report, Chapter 3|accessdate=2009-03-14|date=2007-02-05|pages=237}}</ref> 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.<ref>{{Cite journal|title=Land/sea warming ratio in response to climate change: IPCC AR4 model results and comparison with observations|author=Rowan T. Sutton, Buwen Dong, Jonathan M. Gregory|journal=Geophysical Research Letters|volume=34|url=http://www.agu.org/pubs/crossref/2007/2006GL028164.shtml|doi=10.1029/2006GL028164|year=2007|accessdate=2007-09-19|pages=L02701}}</ref> 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.<ref>{{Cite book|chapterurl=http://www.grida.no/publications/other/ipcc_tar/?src=/CLIMATE/IPCC_TAR/WG1/127.htm|title=Climate Change 2001: The Scientific Basis|chapter=Atmospheric Chemistry and Greenhouse Gases|url=http://www.grida.no/publications/other/ipcc_tar/?src=/CLIMATE/IPCC_TAR/WG1/|author=Intergovernmental Panel on Climate Change|authorlink=Intergovernmental Panel on Climate Change|publisher=Cambridge University Press|location=Cambridge, UK|year=2001|isbn=0521014956}}</ref>
Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25&nbsp;°C per decade against 0.13&nbsp;°C per decade).<ref>{{Cite web|url=http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter3.pdf|format=PDF|title=IPCC Fourth Assessment Report, Chapter 3|accessdate=2009-03-14|date=2007-02-05|pages=237}}</ref> 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.<ref>{{Cite journal|title=Land/sea warming ratio in response to climate change: IPCC AR4 model results and comparison with observations|author=Rowan T. Sutton, Buwen Dong, Jonathan M. Gregory|journal=Geophysical Research Letters|volume=34|url=http://www.agu.org/pubs/crossref/2007/2006GL028164.shtml|doi=10.1029/2006GL028164|year=2007|accessdate=2007-09-19|pages=L02701}}</ref> 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.<ref>{{Cite book|chapterurl=http://www.grida.no/publications/other/ipcc_tar/?src=/CLIMATE/IPCC_TAR/WG1/127.htm|title=Climate Change 2001: The Scientific Basis|chapter=Atmospheric Chemistry and Greenhouse Gases|url=http://www.grida.no/publications/other/ipcc_tar/?src=/CLIMATE/IPCC_TAR/WG1/|author=Intergovernmental Panel on Climate Change|authorlink=Intergovernmental Panel on Climate Change|publisher=Cambridge University Press|location=Cambridge, UK|year=2001|isbn=0521014956}}</ref>
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==Views and reactions==
==Views on global warming==


{{Main|Global warming controversy|Politics of global warming}}
{{Main|Global warming controversy|Politics of global warming}}
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|isbn=9780521568548
|doi=10.2277/0521568544}}</ref> These competing views weigh the benefits of limiting emissions of greenhouse gases against the costs. In general, it seems likely that climate change will impose greater damages and risks in poorer regions.<ref>Banuri ''et al.'', 1996, p.&nbsp;83</ref>
|doi=10.2277/0521568544}}</ref> These competing views weigh the benefits of limiting emissions of greenhouse gases against the costs. In general, it seems likely that climate change will impose greater damages and risks in poorer regions.<ref>Banuri ''et al.'', 1996, p.&nbsp;83</ref>

=== Oil industry reaction ===
{{undue-section}}
As human-caused global warming reached [[Scientific opinion on climate change|global scientific consensus]] and public attention, some oil companies such as, [[ExxonMobil]] and [[Koch Industries]] have reacted by funding think-tanks, organizations, [[Lobbying|lobbyists]] and [[Political Campaign|political campaigns]] that attempt to deny the facts<ref name=exxoncontinues>{{Citation| last = Adam| first = David| title = ExxonMobil continuing to fund climate sceptic groups, records show| newspaper = The Guardian| location = London| date = 1 July 2009| url= http://www.guardian.co.uk/environment/2009/jul/01/exxon-mobil-climate-change-sceptics-funding}}</ref><ref name=koch>{{Citation| last = Vidal| first = John| title = US oil company donated millions to climate sceptic groups, says Greenpeace| newspaper = The Guardian| location = London| date = 30 March 2010| url =http://www.guardian.co.uk/environment/2010/mar/30/us-oil-donated-millions-climate-sceptics }}</ref>. The organizations continue to publish [[Climate change denial|global warming denials]], oppose government environmental regulations, publish the risks to business if climate change action is taken, advocate for inaction, and claim that the ''reduction'' of air pollutants would be bad for public health.<ref name=koch/>

From 2005-2008, Koch Industries has directly or indirectly funded the following organizations: [[Mercatus Center]] ($9.2 million), [[Americans for prosperity]] ($5.17 million), [[Institute for Humane Studies]] ($1.96 million), [[Heritage foundation]] ($1.62 million), [[Cato Institute]] ($1.02 million), [[Manhattan Institute for Policy Research|Manhattan Institute]] ($800,000), [[Washington Legal Foundation]] ($655,000), [[Federalist Society|Federalist society for law]] ($542,000), [[National center for policy analysis]] ($130,000), [[American council on science and health]] ($113,800).<ref name=koch/>

[[Naomi Oreskes]], an award-winning<ref>{{Citation| last =Naomi| first =Oreskes| title = Profile - Department of History| url =http://historyweb.ucsd.edu/oreskes/pages/profile.html}}</ref> professor of history and science has written a book based on her research called [http://www.bloomsburypress.com/books/catalog/merchants_of_doubt_hc_104 ''Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming]. She describes how a small group of scientists for example, [[Fred Seitz]], [[Fred Singer]] and [[William Nierenberg|Bill Nierenberg]], are hired again and again by companies to cast doubt on issues of scientific consensus such as, human-caused global warming, tobacco causing cancer, the depletion of the ozone layer and many other extremely serious topics. "[The [[Advancement of Sound Science Center]]] is operated by [[Steven Milloy]], a self-described [[libertarianism|libertarian]] and columnist at [[Fox News Channel|FoxNews.com]]. Milloy once wrote an article blasting the [[Arctic Climate Impact Assessment]]...[at] the time, it was not revealed that Milloy got money from [[ExxonMobil]]."<ref>{{Citation| last = Brown| first = Seth| title = 'Merchants of Doubt' delves into contrarian scientists| newspaper = USA TODAY| location = McLean| date = 1 June 2010| url= http://www.usatoday.com/money/books/reviews/2010-06-01-deathmerchants01_ST_N.htm?csp=34tech&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+usatoday-TechTopStories+%28Tech+-+Top+Stories%29}}</ref>


=== Politics ===
=== Politics ===
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|publisher=American Institute of Physics website
|accessdate=2010-05-05}}</ref>{{page number}}
|accessdate=2010-05-05}}</ref><ref>{{cite web
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|author=SEPP
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|url=http://www.sepp.org/FAQ/faq.html
|publisher=Science & Environmental Policy Project (SEPP) website
|accessdate=2010-05-05}}</ref>


Organizations such as the libertarian [[Competitive Enterprise Institute]], conservative commentators, and companies such as [[ExxonMobil]] have challenged IPCC climate change scenarios, funded scientists who disagree with the [[Scientific opinion on climate change|scientific consensus]], and provided their own projections of the economic cost of stricter controls.<ref>{{Cite news
Organizations such as the libertarian [[Competitive Enterprise Institute]], conservative commentators, and companies such as [[ExxonMobil]] have challenged IPCC climate change scenarios, funded scientists who disagree with the [[Scientific opinion on climate change|scientific consensus]], and provided their own projections of the economic cost of stricter controls.<ref>{{Cite news

Revision as of 17:15, 5 June 2010

Global mean surface temperature difference relative to the 1961–1990 average
Comparison of ground based (blue) and satellite based (red: UAH; green: RSS) records of temperature variations since 1979. Trends plotted since January 1982.
Mean surface temperature change for the period 2000 to 2009 relative to the average temperatures from 1951 to 1980.[1]

Global warming is the increase in the average temperature of Earth's near-surface air and oceans since the mid-20th century and its projected continuation. According to a report by the Intergovernmental Panel on Climate Change (IPCC) global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) between the start and the end of the 20th century.[2][A] The climatology literature uniformly states that most of the observed temperature increase since the middle of the 20th century was caused by increasing concentrations of greenhouse gases, which results from human activity such as fossil fuel burning and deforestation.[3]

Climate model projections summarized in the latest IPCC report indicate that the global surface temperature is likely to rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the 21st century.[2] The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts.[4] Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost and sea ice. Other likely effects include changes in the frequency and intensity of extreme weather events, species extinctions, and changes in agricultural yields. Warming and related changes will vary from region to region around the globe, though the nature of these regional variations is uncertain.[5]

The overwhelming scientific consensus is that human-made global warming is real.[6][7] Nevertheless, political and public debate continues. Some oil companies have funded public relations campaigns and deeply flawed research studies[8] intended to discredit the global scientific consensus.[9][10]

Temperature changes

Two millennia of mean surface temperatures according to different reconstructions, each smoothed on a decadal scale. The instrumental record and the unsmoothed annual value for 2004 are shown in black.

Evidence for warming of the climate system includes observed increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.[11][12][13][14][15] The most common measure of global warming is the trend in globally averaged temperature near the Earth's surface. Expressed as a linear trend, this 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 °C ± 0.02 °C per decade). The urban heat island effect is estimated to account for about 0.002 °C of warming per decade since 1900.[16] 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. Temperature is believed 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.[17]

Estimates by NASA's Goddard Institute for Space Studies and the National Climatic Data Center show that 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree.[18][19] Estimates prepared by the World Meteorological Organization and the Climatic Research Unit show 2005 as the second warmest year, behind 1998.[20][21] Temperatures in 1998 were unusually warm because the strongest El Niño in the past century occurred during that year.[22] 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.[23][24]

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).[25] 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.[26] 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.[27]

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.[28]

External forcings

External forcing refers to processes external to the climate system (though not necessarily external to Earth) that influence climate. Climate responds to several types of external forcing, such as radiative forcing due to changes in atmospheric composition (mainly greenhouse gas concentrations), changes in solar luminosity, volcanic eruptions, and variations in Earth's orbit around the Sun.[29] Attribution of recent climate change focuses on the first three types of forcing. Orbital cycles vary slowly over tens of thousands of years and thus are too gradual to have caused the temperature changes observed in the past century.

Greenhouse gases

The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in the atmosphere are purported to 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.[30] The question in terms of global warming is how the strength of the presumed greenhouse effect changes when human activity increases the concentrations of greenhouse gases in the atmosphere.

Naturally occurring greenhouse gases have a mean warming effect of about 33 °C (59 °F).[31][C] The major greenhouse gases are water vapor, which causes about 36–70 percent of the greenhouse effect; carbon dioxide (CO2), which causes 9–26 percent; methane (CH4), which causes 4–9 percent; and ozone (O3), which causes 3–7 percent.[32][33][34] Clouds also affect the radiation balance, but they are composed of liquid water or ice and so have different effects on radiation from water vapor.

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.[35] These levels are much higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from ice cores.[36][37][38] Less direct geological evidence indicates that CO2 values higher than this were last seen about 20 million years ago.[39] Fossil fuel burning has produced about three-quarters of the increase in CO2 from human activity over the past 20 years. Most of the rest is due to land-use change, particularly deforestation.[40]

CO2 concentrations are continuing to rise due to burning of fossil fuels and land-use change. The future rate of rise will depend on uncertain economic, sociological, technological, and natural developments. Accordingly, the IPCC Special Report on Emissions Scenarios gives a wide range of future CO2 scenarios, ranging from 541 to 970 ppm by the year 2100 (an increase by 90-250% since 1750).[41] Fossil fuel reserves are sufficient to reach these levels and continue emissions past 2100 if coal, tar sands or methane clathrates are extensively exploited.[42]

The destruction of stratospheric ozone by chlorofluorocarbons is sometimes mentioned in relation to global warming. Although there are a few areas of linkage, the relationship between the two is not strong. Reduction of stratospheric ozone has a cooling influence, but substantial ozone depletion did not occur until the late 1970s.[43] Ozone in the troposphere (the lowest part of the Earth's atmosphere) does contribute to surface warming.[44]

Aerosols and soot

Ship tracks over the Atlantic Ocean on the east coast of the United States. The climatic impacts from aerosol forcing could have a large effect on climate through the indirect effect.

Global dimming, a gradual reduction in the amount of global direct irradiance at the Earth's surface, has partially counteracted global warming from 1960 to the present.[45] The main cause of this dimming is aerosols produced by volcanoes and pollutants. These aerosols exert a cooling effect by increasing the reflection of incoming sunlight. James E. Hansen and colleagues have proposed that the effects of the products of fossil fuel combustion—CO2 and aerosols—have largely offset one another in recent decades, so that net warming has been driven mainly by non-CO2 greenhouse gases.[46]

In addition to their direct effect by scattering and absorbing solar radiation, aerosols have indirect effects on the radiation budget.[47] Sulfate aerosols act as cloud condensation nuclei and thus lead to clouds that have more and smaller cloud droplets. These clouds reflect solar radiation more efficiently than clouds with fewer and larger droplets.[48] This effect also causes droplets to be of more uniform size, which reduces growth of raindrops and makes the cloud more reflective to incoming sunlight.[49]

Soot may cool or warm, depending on whether it is airborne or deposited. Atmospheric soot aerosols directly absorb solar radiation, which heats the atmosphere and cools the surface. In isolated areas with high soot production, such as rural India, as much as 50% of surface warming due to greenhouse gases may be masked by atmospheric brown clouds.[50] When deposited, especially on glaciers or on ice in arctic regions, the lower surface albedo can also directly heat the surface.[51] The influences of aerosols, including black carbon, are most pronounced in the tropics and sub-tropics, particularly in Asia, while the effects of greenhouse gases are dominant in the extratropics and southern hemisphere.[52]

Solar variation

Solar variation over the last thirty years.

Variations in solar output have been the cause of past climate changes.[53] The consensus among climate scientists is that changes in solar forcing probably had a slight cooling effect in recent decades. This result is less certain than some others, with a few papers suggesting a warming effect.[29][54][55][56]

Greenhouse gases and solar forcing affect temperatures in different ways. While both increased solar activity and increased greenhouse gases are expected to warm the troposphere, an increase in solar activity should warm the stratosphere while an increase in greenhouse gases should cool the stratosphere.[29] Observations show that temperatures in the stratosphere have been cooling since 1979, when satellite measurements became available. Radiosonde (weather balloon) data from the pre-satellite era show cooling since 1958, though there is greater uncertainty in the early radiosonde record.[57]

A related hypothesis, proposed by Henrik Svensmark, is that magnetic activity of the sun deflects cosmic rays that may influence the generation of cloud condensation nuclei and thereby affect the climate.[58] Other research has found no relation between warming in recent decades and cosmic rays.[59][60] A recent study concluded that the influence of cosmic rays on cloud cover is about a factor of 100 lower than needed to explain the observed changes in clouds or to be a significant contributor to present-day climate change.[61]

Feedback

Feedback is a 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. Feedback is important in the study of global warming because it may amplify or diminish the effect of a particular process. The main positive feedback in global warming is the tendency of warming to increase the amount of water vapor in the atmosphere, a significant greenhouse gas. The main negative feedback is radiative cooling, which increases as the fourth power of temperature; the amount of heat radiated from the Earth into space increases with the temperature of Earth's surface and atmosphere. Imperfect understanding of feedbacks is a major cause of uncertainty and concern about global warming.

Climate models

The main tools for projecting future climate changes are mathematical models based on physical principles including fluid dynamics, thermodynamics and radiative transfer. Although they attempt to include as many processes as possible, simplifications of the actual climate system are inevitable because of the constraints of available computer power and limitations in knowledge of the climate system. All modern climate models are in fact combinations of models for different parts of the Earth. These include an atmospheric model for air movement, temperature, clouds, and other atmospheric properties; an ocean model that predicts temperature, salt content, and circulation of ocean waters; models for ice cover on land and sea; and a model of heat and moisture transfer from soil and vegetation to the atmosphere. Some models also include treatments of chemical and biological processes.[62] Warming due to increasing levels of greenhouse gases is not an assumption of the models; rather, it is an end result from the interaction of greenhouse gases with radiative transfer and other physical processes.[63] Although much of the variation in model outcomes depends on the greenhouse gas emissions used as inputs, the temperature effect of a specific greenhouse gas concentration (climate sensitivity) varies depending on the model used. The representation of clouds is one of the main sources of uncertainty in present-generation models.[64]

Global climate model projections of future climate most often have used estimates of greenhouse gas emissions from the IPCC Special Report on Emissions Scenarios (SRES). In addition to human-caused emissions, some models also include a simulation of the carbon cycle; this generally shows a positive feedback, though this response is uncertain. Some observational studies also show a positive feedback.[65][66][67] Including uncertainties in future greenhouse gas concentrations and climate sensitivity, the IPCC anticipates a warming of 1.1 °C to 6.4 °C (2.0 °F to 11.5 °F) by the end of the 21st century, relative to 1980–1999.[2]

Models are also used to help investigate the causes of recent climate change by comparing the observed changes to those that the models project from various natural and human-derived causes. Although these models do not unambiguously attribute the warming that occurred from approximately 1910 to 1945 to either natural variation or human effects, they do indicate that the warming since 1970 is dominated by man-made greenhouse gas emissions.[29]

The physical realism of models is tested by examining their ability to simulate current or past climates.[68] Current climate models produce a good match to observations of global temperature changes over the last century, but do not simulate all aspects of climate.[40] Not all effects of global warming are accurately predicted by the climate models used by the IPCC. For example, observed Arctic shrinkage has been faster than that predicted.[69]

Attributed and expected effects

Global warming may be detected in natural, ecological or social systems as a change having statistical significance.[70] Attribution of these changes e.g., to natural or human activities, is the next step following detection.[71]

Natural systems

Sparse records indicate that glaciers have been retreating since the early 1800s. In the 1950s measurements began that allow the monitoring of glacial mass balance, reported to the WGMS and the NSIDC.

Global warming has been detected in a number of systems. Some of these changes, e.g., based on the instrumental temperature record, have been described in the section on temperature changes. Rising sea levels and observed decreases in snow and ice extent are consistent with warming.[15] Most of the increase in global average temperature since the mid-20th century is, with high probability,[D] atttributable to human-induced changes in greenhouse gas concentrations.[72]

Even with current policies to reduce emissions, global emissions are still expected to continue to grow over the coming decades.[73] Over the course of the 21st century, increases in emissions at or above their current rate would very likely induce changes in the climate system larger than those observed in the 20th century.

In the IPCC Fourth Assessment Report, across a range of future emission scenarios, model-based estimates of sea level rise for the end of the 21st century (the year 2090-2099, relative to 1980-1999) range from 0.18 to 0.59 m. These estimates, however, were not given a likelihood due to a lack of scientific understanding, nor was an upper bound given for sea level rise. Over the course of centuries to millennia, the melting of ice sheets could result in sea level rise of 4–6 m or more.[74]

Changes in regional climate are expected to include greater warming over land, with most warming at high northern latitudes, and least warming over the Southern Ocean and parts of the North Atlantic Ocean.[73] Snow cover area and sea ice extent are expected to decrease. The frequency of hot extremes, heat waves and heavy precipitation will very likely increase.

Ecological systems

In terrestrial ecosystems, the earlier timing of spring events, and poleward and upward shifts in plant and animal ranges, have been linked with high confidence to recent warming.[15] Future climate change is expected to particularly affect certain ecosystems, including tundra, mangroves, and coral reefs.[73] It is expected that most ecosystems will be affected by higher atmospheric CO2 levels, combined with higher global temperatures.[75] Overall, it is expected that climate change will result in the extinction of many species and reduced diversity of ecosystems.[76]

Social systems

There is some evidence of regional climate change affecting systems related to human activities, including agricultural and forestry management activities at higher latitudes in the Northern Hemisphere.[15] Future climate change is expected to particularly affect some sectors and systems related to human activities.[73] These include:

  • Water resources in some dry regions at mid-latitudes, the dry tropics, and areas that depend on snow and ice melt
  • Agriculture in low latitudes
  • Low-lying coastal systems
  • Human health in populations with limited capacity to adapt to climate change

It is expected that some regions will be particularly affected by climate change, including the Arctic, Africa, small islands, and Asian and African megadeltas. Some people, such as the poor, young children, and the elderly, are particularly at risk, even in high-income areas.

Responses to global warming

Carbon capture and storage (CCS) is an approach to mitigation. Emissions may be sequestered from fossil fuel power plants, or removed during processing in hydrogen production. When used on plants, it is known as bio-energy with carbon capture and storage.

Reducing the amount of future climate change is called mitigation of climate change. The IPCC defines mitigation as activities that reduce greenhouse gas (GHG) emissions, or enhance the capacity of carbon sinks to absorb GHGs from the atmosphere.[77] Many countries, both developing and developed, are aiming to use cleaner, less polluting, technologies.[78] Use of these technologies aids mitigation and could result in substantial reductions in CO2 emissions. Policies include targets for emissions reductions, increased use of renewable energy, and increased energy efficiency. Studies indicate substantial potential for future reductions in emissions.[79]

Other policy responses include adaptation to climate change. Adaptation to climate change may be planned, e.g., by local or national government, or spontaneous, i.e., done privately without government intervention.[80] The ability to adapt (called "adaptive capacity") is closely linked to social and economic development.[79] Even societies with high capacities to adapt are still vulnerable to climate change. Planned adaptation is already occurring on a limited basis. The barriers, limits, and costs of future adaptation are not fully understood.

Another policy response is engineering of the climate (geoengineering). This policy response is sometimes grouped together with mitigation.[81] Geoengineering is largely unproven, and reliable cost estimates for it have not yet been published.[82]

UNFCCC

Most countries are Parties to the United Nations Framework Convention on Climate Change (UNFCCC).[83] The ultimate objective of Convention is the prevent "dangerous" human interference of the climate system.[84] As is stated in the Convention, this requires that GHGs are stabilized in the atmosphere at a level where:

  • ecosystems can adapt naturally to climate change;
  • food production is not threatened;
  • economic development can proceed in a sustainable fashion.

The UNFCCC recognizes differences among countries in their responsibility to act on climate change.[85] In the Kyoto Protocol to the UNFCCC, most developed countries (listed in Annex I of the treaty) took on legally binding commitments to reduce their emissions.[86] Policy measures taken in response to these commitments have reduced emissions.[87] For many developing (non-Annex I) countries, reducing poverty is their overriding aim.[88]

At the 15th UNFCCC Conference of the Parties, held in 2009 at Copenhagen, several UNFCCC Parties produced the Copenhagen Accord.[89] Parties agreeing with the Accord aim to limit the future increase in global mean temperature to below 2 °C.[90]

Views on global warming

There are different views over what the appropriate policy response to climate change should be.[91][92] These competing views weigh the benefits of limiting emissions of greenhouse gases against the costs. In general, it seems likely that climate change will impose greater damages and risks in poorer regions.[93]

Politics

Developing and developed countries have made different arguments over who should bear the burden of costs for cutting emissions. Developing countries often concentrate on per capita emissions, that is, the total emissions of a country divided by its population.[94] Per capita emissions in the industrialized countries are typically as much as ten times the average in developing countries.[95] This is used to make the argument that the real problem of climate change is due to the profligate and unsustainable lifestyles of those living in rich countries.[94] On the other hand, commentators from developed countries more often point out that it is total emissions that matter.[94] In 2008, developing countries made up around half of the world's total emissions of CO2 from cement production and fossil fuel use.[96]

The Kyoto Protocol, which came into force in 2005, sets legally binding emission limitations for most developed countries.[86] Developing countries are not subject to limitations. This exemption led the U.S. (under President George W. Bush) and a previous Australian Government to decide not to ratify the treaty.[97][98] At the time, almost all world leaders expressed their disappointment over President Bush's decision.[98] Australia has since ratified the Kyoto protocol.[99]

Public opinion

In 2007–2008 Gallup Polls surveyed 127 countries. Over a third of the world's population was unaware of global warming, with people in developing countries less aware than those in developed, and those in Africa the least aware. Of those aware, Latin America leads in belief that temperature changes are a result of human activities while Africa, parts of Asia and the Middle East, and a few countries from the Former Soviet Union lead in the opposite belief.[100] In the Western world, opinions over the concept and the appropriate responses are divided. Nick Pidgeon of Cardiff University finds that "results show the different stages of engagement[clarification needed] about global warming on each side of the Atlantic"; where Europe debates the appropriate responses while the United States debates whether climate change is happening.[101][102][vague][dubiousdiscuss]

Other views

Most scientists accept that humans are contributing to observed climate change.[103][104] National science academies have called on world leaders for policies to cut global emissions.[105] There are, however, some scientists and non-scientists who question aspects of climate change science.[106][107]

Organizations such as the libertarian Competitive Enterprise Institute, conservative commentators, and companies such as ExxonMobil have challenged IPCC climate change scenarios, funded scientists who disagree with the scientific consensus, and provided their own projections of the economic cost of stricter controls.[108][109][110][111] Environmental organizations and public figures have emphasized changes in the current climate and the risks they entail, while promoting adaptation to changes in infrastructural needs and emissions reductions.[112] Some fossil fuel companies have scaled back their efforts in recent years,[113] or called for policies to reduce global warming.[114]

Many studies link population growth with emissions and the effect of climate change.[115][116]

See also

Notes

  1. ^
    Increase is for years 1905 to 2005. Global surface temperature is defined in the IPCC Fourth Assessment Report as the average of near-surface air temperature over land and sea surface temperature. These error bounds are constructed with a 90% confidence interval.
  2. ^
  3. ^
    Note that the greenhouse effect produces an average worldwide temperature increase of about 33 °C (59 °F) compared to black body predictions without the greenhouse effect, not an average surface temperature of 33 °C (91 °F). The average worldwide surface temperature is about 14 °C (57 °F).
  4. ^
    In the IPCC Fourth Assessment Report, published in 2007, this attribution is given a probability of greater than 90%, based on expert judgement.[117] According to the US National Research Council Report – Understanding and Responding to Climate Change - published in 2008, "[most] scientists agree that the warming in recent decades has been caused primarily by human activities that have increased the amount of greenhouse gases in the atmosphere."[103]

References

  1. ^ 2009 Ends Warmest Decade on Record. NASA Earth Observatory Image of the Day, January 22, 2010.
  2. ^ a b c IPCC (2007-05-04). "Summary for Policymakers" (PDF). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Retrieved 2009-07-03.
  3. ^ "Understanding and Responding to Climate Change" (PDF). United States National Academy of Sciences. 2008. Retrieved 30 May 2010. Most scientists agree that the warming in recent decades has been caused primarily by human activities that have increased the amount of greenhouse gases in the atmosphere.
  4. ^ Lu, Jian (2007). "Expansion of the Hadley cell under global warming" (PDF). Geophysical Research Letters. 34: L06805. doi:10.1029/2006GL028443. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  5. ^ IPCC (2007). 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 (Full free text). [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. Geneva, Switzerland: IPCC.
  6. ^ Oreskes, Naomi (December 2004), "BEYOND THE IVORY TOWER: The Scientific Consensus on Climate Change", Science, 306: 1686, Such statements suggest that there might be substantive disagreement in the scientific community about the reality of anthropogenic climate change. This is not the case. [...] Politicians, economists, journalists, and others may have the impression of confusion, disagreement, or discord among climate scientists, but that impression is incorrect.{{citation}}: CS1 maint: date and year (link)
  7. ^ Union of Concerned Scientists, 2009, "Scientific Consensus on Global Warming"
  8. ^ Sanchez, Irene (12 September 2003), "Warming Study Draws Fire Harvard scientists accused of politicizing research", The Harvard Crimson, Cambridge
  9. ^ Vidal, John (30 March 2010), "US oil company donated millions to climate sceptic groups, says Greenpeace", The Guardian, London
  10. ^ Sample, Ian (2 February 2007), "Scientists offered cash to dispute climate study", The Guardian, London
  11. ^ Joint science academies’ statement (2007). "Joint science academies' statement: sustainability, energy efficiency and climate protection". UK Royal Society website. Retrieved 2010-04-17. {{cite web}}: |author= has generic name (help); Unknown parameter |day= ignored (help); Unknown parameter |month= ignored (help)
  12. ^ NRC (2008). "Understanding and Responding to Climate Change" (PDF). Board on Atmospheric Sciences and Climate, US National Academy of Sciences. p. 4. Retrieved 2009-05-20. {{cite web}}: External link in |publisher= (help)
  13. ^ Slingo, J. (n.d.). "Explaining the evidence of climate change". UK Met Office website. Retrieved 2010-04-17.
  14. ^ USGRCP (n.d.). "Key Findings. On (website): Global Climate Change Impacts in the United States". U.S. Global Change Research Program website. Retrieved 2010-04-17.
  15. ^ a b c d IPCC (2007). "1. Observed changes in climate and their effects. In (section): Summary for Policymakers. In (book): 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 (Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.))". Book publisher: IPCC, Geneva, Switzerland. This version: IPCC website. Retrieved 2010-04-17.
  16. ^ Trenberth, Kevin E. (2007). "Chapter 3: Observations: Surface and Atmospheric Climate Change". IPCC Fourth Assessment Report (PDF). Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press. p. 244. {{cite book}}: External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  17. ^ Jansen, E., J. Overpeck; Briffa, K.R.; Duplessy, J.-C.; Joos, F.; Masson-Delmotte, V.; Olago, D.; Otto-Bliesner, B.; Peltier, W.R.; Rahmstorf, S.; Ramesh, R.; Raynaud, D.; Rind, D.; Solomina, O.; Villalba; Zhang, R. (2007-02-11). "Palaeoclimate". In Solomon, S.; Qin, D.; Manning, Z.; Chen, M.; Marquis; Averyt, K.B.; Tignor, M.; Miller, H.L. (eds.). Climate Change 2007: The Physical Science Basis : contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. IPCC Fourth Assessment Report. Cambridge and New York: Cambridge University Press. pp. 466–478. ISBN 978-0521705967. OCLC 132298563. {{cite book}}: |first16= missing |last16= (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)CS1 maint: multiple names: authors list (link)
  18. ^ Hansen, James E. (2006-01-12). "Goddard Institute for Space Studies, GISS Surface Temperature Analysis". NASA Goddard Institute for Space Studies. Retrieved 2007-01-17. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  19. ^ "NOAA/NCDC 2009 climate". Retrieved 2010-02-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  20. ^ "Global Temperature for 2005: second warmest year on record" (PDF). Climatic Research Unit, School of Environmental Sciences, University of East Anglia. 2005-12-15. Retrieved 2007-04-13.
  21. ^ "WMO statement on the status of the global climate in 2005" (PDF). World Meteorological Organization. 2005-12-15. Retrieved 2009-04-24.
  22. ^ Changnon, Stanley A. (2000). El Niño, 1997–1998: The Climate Event of the Century. London: Oxford University Press. ISBN 0195135520. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  23. ^ Knight, J.; Kenney, J.J.; Folland, C.; Harris, G.; Jones, G.S.; Palmer, M.; Parker, D.; Scaife, A.; Stott, P. (August 2009). "Do Global Temperature Trends Over the Last Decade Falsify Climate Predictions? [in "State of the Climate in 2008"]" (PDF). Bull.Amer.Meteor.Soc. 90 (8): S75–S79. Retrieved 2009-09-08.
  24. ^ Global temperature slowdown — not an end to climate change. UK Met Office. Retrieved 2009-09-08.
  25. ^ "IPCC Fourth Assessment Report, Chapter 3" (PDF). 2007-02-05. p. 237. Retrieved 2009-03-14.
  26. ^ Rowan T. Sutton, Buwen Dong, Jonathan M. Gregory (2007). "Land/sea warming ratio in response to climate change: IPCC AR4 model results and comparison with observations". Geophysical Research Letters. 34: L02701. doi:10.1029/2006GL028164. Retrieved 2007-09-19.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  27. ^ Intergovernmental Panel on Climate Change (2001). "Atmospheric Chemistry and Greenhouse Gases". Climate Change 2001: The Scientific Basis. Cambridge, UK: Cambridge University Press. ISBN 0521014956. {{cite book}}: External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
  28. ^ Meehl, Gerald A. (2005-03-18). "How Much More Global Warming and Sea Level Rise" (PDF). Science. 307 (5716): 1769–1772. doi:10.1126/science.1106663. PMID 15774757. Retrieved 2007-02-11. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  29. ^ a b c d Hegerl, Gabriele C. (2007). "Understanding and Attributing Climate Change" (PDF). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. IPCC. Recent estimates indicate a relatively small combined effect of natural forcings on the global mean temperature evolution of the second half of the 20th century, with a small net cooling from the combined effects of solar and volcanic forcings. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  30. ^ Weart, Spencer (2008). "The Carbon Dioxide Greenhouse Effect". The Discovery of Global Warming. American Institute of Physics. Retrieved 21 April 2009.
  31. ^ IPCC (2007). "Chapter 1: Historical Overview of Climate Change Science" (PDF). IPCC WG1 AR4 Report. IPCC. pp. p97 (PDF page 5 of 36). Retrieved 21 April 2009. To emit 240 W m–2, a surface would have to have a temperature of around −19 °C. This is much colder than the conditions that actually exist at the Earth's surface (the global mean surface temperature is about 14 °C). Instead, the necessary −19 °C is found at an altitude about 5 km above the surface. {{cite web}}: |pages= has extra text (help)
  32. ^ Kiehl, J.T.; Trenberth, K.E. (1997). "Earth's Annual Global Mean Energy Budget" (PDF). Bulletin of the American Meteorological Society. 78 (2): 197–208. doi:10.1175/1520-0477(1997)078<0197:EAGMEB>2.0.CO;2. Retrieved 21 April 2009.
  33. ^ Schmidt, Gavin (6 Apr 2005). "Water vapour: feedback or forcing?". RealClimate. Retrieved 21 April 2009.{{cite web}}: CS1 maint: year (link)
  34. ^ Russell, Randy (May 16, 2007). "The Greenhouse Effect & Greenhouse Gases". University Corporation for Atmospheric Research Windows to the Universe. Retrieved Dec 27, 2009.
  35. ^ EPA (2007). "Recent Climate Change: Atmosphere Changes". Climate Change Science Program. United States Environmental Protection Agency. Retrieved 21 April 2009.
  36. ^ Spahni, Renato (2005). "Atmospheric Methane and Nitrous Oxide of the Late Pleistocene from Antarctic Ice Cores". Science. 310 (5752): 1317–1321. doi:10.1126/science.1120132. PMID 16311333. Retrieved 27 December 2009. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  37. ^ Siegenthaler, Urs (2005). "Stable Carbon Cycle–Climate Relationship During the Late Pleistocene" (PDF). Science. 310 (5752): 1313–1317. doi:10.1126/science.1120130. PMID 16311332. Retrieved 27 December 2009. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  38. ^ Petit, J. R. (3 June 1999). "Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica" (PDF). Nature. 399 (6735): 429–436. doi:10.1038/20859. Retrieved 27 December 2009. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  39. ^ Pearson, PN; Palmer, MR (2000). "Atmospheric carbon dioxide concentrations over the past 60 million years". Nature. 406 (6797): 695–699. doi:10.1038/35021000. PMID 10963587. {{cite journal}}: More than one of |author= and |last1= specified (help)
  40. ^ a b IPCC (2001). "Summary for Policymakers" (PDF). Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. IPCC. Retrieved 21 April 2009.
  41. ^ Prentice, I.C.; et al. (2001). "The Carbon Cycle and Atmospheric Carbon Dioxide: SRES scenarios and their implications for future CO2 concentration". Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. IPCC. Retrieved 21 April 2009. {{cite web}}: Explicit use of et al. in: |author= (help)
  42. ^ Nakicenovic., N.; et al. (2001). "An Overview of Scenarios: Resource Availability". IPCC Special Report on Emissions Scenarios. IPCC. Retrieved 21 April 2009. {{cite web}}: Explicit use of et al. in: |author= (help)
  43. ^ Sparling, Brien (May 30, 2001). "Ozone Depletion, History and politics". NASA. Retrieved 2009-02-15.
  44. ^ Shindell, Drew; Faluvegi, Greg; Lacis, Andrew; Hansen, James; Ruedy, Reto; Aguilar, Elliot (2006). "Role of tropospheric ozone increases in 20th-century climate change". Journal of Geophysical Research. 111: D08302. doi:10.1029/2005JD006348.
  45. ^ Mitchell, J.F.B.; et al. (2001). "Detection of Climate Change and Attribution of Causes: Space-time studies". Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. IPCC. Retrieved 21 April 2009. {{cite web}}: Explicit use of et al. in: |author= (help)
  46. ^ Hansen, J; Sato, M; Ruedy, R; Lacis, A; Oinas, V (2000). "Global warming in the twenty-first century: an alternative scenario". Proc. Natl. Acad. Sci. U.S.A. 97 (18): 9875–80. doi:10.1073/pnas.170278997. PMC 27611. PMID 10944197. {{cite journal}}: More than one of |author= and |last1= specified (help)
  47. ^ Lohmann, U. & J. Feichter (2005). "Global indirect aerosol effects: a review". Atmos. Chem. Phys. 5: 715–737.
  48. ^ Twomey, S. (1977). "Influence of pollution on shortwave albedo of clouds". J. Atmos. Sci. 34: 1149–1152. doi:10.1175/1520-0469(1977)034<1149:TIOPOT>2.0.CO;2.
  49. ^ Albrecht, B. (1989). "Aerosols, cloud microphysics, and fractional cloudiness". Science. 245 (4923): 1227–1239. doi:10.1126/science.245.4923.1227. PMID 17747885.
  50. ^ Ramanathan, V.; Chung, C; Kim, D; Bettge, T; Buja, L; Kiehl, JT; Washington, WM; Fu, Q; Sikka, DR (2005). "Atmospheric brown clouds: Impacts on South Asian climate and hydrological cycle". Proc. Natl. Acad. Sci. 102 (15): 5326–5333. doi:10.1073/pnas.0500656102. PMC 552786. PMID 15749818. {{cite journal}}: More than one of |first1= and |first= specified (help); More than one of |last1= and |last= specified (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  51. ^ Ramanathan, V.; et al. (2008). "Report Summary" (PDF). Atmospheric Brown Clouds: Regional Assessment Report with Focus on Asia. United Nations Environment Programme. {{cite web}}: Explicit use of et al. in: |author= (help)
  52. ^ Ramanathan, V.; et al. (2008). "Part III: Global and Future Implications" (PDF). Atmospheric Brown Clouds: Regional Assessment Report with Focus on Asia. United Nations Environment Programme. {{cite web}}: Explicit use of et al. in: |author= (help)
  53. ^ National Research Council (1994). Solar Influences On Global Change. Washington, D.C.: National Academy Press. p. 36. ISBN 0-309-05148-7.
  54. ^ Duffy, Santer and Wigley, "Solar variability does not explain late-20th-century warming" Physics Today, January, 2009, pp 48-49. The authors respond to recent assertions by Nicola Scafetta and Bruce West that solar forcing "might account" for up to about half of 20th-century warming.
  55. ^ Hansen, J. (2002). "Climate". Journal of Geophysical Research. 107: 4347. doi:10.1029/2001JD001143. {{cite journal}}: Unknown parameter |unused_data= ignored (help)
  56. ^ Hansen, J. (2005). "Efficacy of climate forcings". Journal of Geophysical Research. 110: D18104. doi:10.1029/2005JD005776.
  57. ^ Randel, William J.; Shine, Keith P.; Austin, John; Barnett, John; Claud, Chantal; Gillett, Nathan P.; Keckhut, Philippe; Langematz, Ulrike; Lin, Roger (2009). "An update of observed stratospheric temperature trends". Journal of Geophysical Research. 114: D02107. doi:10.1029/2008JD010421.
  58. ^ Marsh, Nigel (2000). "Cosmic Rays, Clouds, and Climate" (PDF). Space Science Reviews. 94 (1–2): 215–230. doi:10.1023/A:1026723423896. Retrieved 2007-04-17. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  59. ^ Lockwood, Mike (2007). "Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature" (PDF). Proceedings of the Royal Society A. 463: 2447. doi:10.1098/rspa.2007.1880. Retrieved 2007-07-21. Our results show that the observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever of the mechanisms is invoked and no matter how much the solar variation is amplified {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  60. ^ T Sloan and A W Wolfendale (2008). "Testing the proposed causal link between cosmic rays and cloud cover". Environ. Res. Lett. 3: 024001. doi:10.1088/1748-9326/3/2/024001. {{cite journal}}: More than one of |pages= and |page= specified (help)
  61. ^ Pierce, J.R. and P.J. Adams (2009). "Can cosmic rays affect cloud condensation nuclei by altering new particle formation rates?". Geophysical Research Letters. 36: L09820. doi:10.1029/2009GL037946.
  62. ^ Denman, K.L.; et al. (2007). "Chapter 7, Couplings Between Changes in the Climate System and Biogeochemistry" (PDF). Fourth Assessment Report of the Intergovernmental Panel on Climate Change. IPCC. Retrieved 2008-02-21. {{cite web}}: Explicit use of et al. in: |author= (help)
  63. ^ Hansen, James (2000). Climatic Change: Understanding Global Warming. Health Press. Retrieved 2007-08-18. {{cite book}}: |work= ignored (help)
  64. ^ Stocker, Thomas F. (2001). "7.2.2 Cloud Processes and Feedbacks". Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. IPCC. Retrieved 2007-03-04. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  65. ^ Torn, Margaret (2006). "Missing feedbacks, asymmetric uncertainties, and the underestimation of future warming". Geophysical Research Letters. 33 (10): L10703. doi:10.1029/2005GL025540. L10703. Retrieved 2007-03-04. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  66. ^ Harte, John (2006). "Shifts in plant dominance control carbon-cycle responses to experimental warming and widespread drought". Environmental Research Letters. 1 (1): 014001. doi:10.1088/1748-9326/1/1/014001. 014001. Retrieved 2007-05-02. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  67. ^ Scheffer, Marten (2006). "Positive feedback between global warming and atmospheric CO2 concentration inferred from past climate change" (PDF). Geophysical Research Letters. 33: L10702. doi:10.1029/2005gl025044. Retrieved 2007-05-04. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  68. ^ Randall, D.A.; et al. (2007). "Chapter 8, Climate Models and Their Evaluation" (PDF). Fourth Assessment Report of the Intergovernmental Panel on Climate Change. IPCC. Retrieved 2009-03-21. {{cite web}}: Explicit use of et al. in: |author= (help)
  69. ^ Stroeve, J.; et al. (2007). "Arctic sea ice decline: Faster than forecast". Geophysical Research Letters. 34: L09501. doi:10.1029/2007GL029703. {{cite journal}}: Explicit use of et al. in: |author= (help)
  70. ^ IPCC (2007d). "1.1 Observations of climate change. In (section): Synthesis Report. In (book): 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 (Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.))". Book version: IPCC, Geneva, Switzerland. This version: IPCC website. Retrieved 2010-04-26.
  71. ^ IPCC (2007d). "2.4 Attribution of climate change. In (section): Synthesis Report. In (book): 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 (Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.))". Book version: IPCC, Geneva, Switzerland. This version: IPCC website. Retrieved 2010-04-26.
  72. ^ IPCC (2007d). "2. Causes of change. In (section): Summary for Policymakers. In (book): 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 (Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.))". Book version: IPCC, Geneva, Switzerland. This version: IPCC website. Retrieved 2010-04-26.
  73. ^ a b c d IPCC (2007d). "3. Projected climate change and its impacts. In (section): Summary for Policymakers. In (book): 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 (Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.))". Book version: IPCC, Geneva, Switzerland. This version: IPCC website. Retrieved 2010-04-26.
  74. ^ IPCC (2007b). "Magnitudes of impact. In (section): Summary for Policymakers. In (book): Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds.)". Book version: Cambridge University Press, Cambridge, UK. This version: IPCC website. Retrieved 2010-04-26.
  75. ^ Fischlin, A., G.F. Midgley, J.T. Price, R. Leemans, B. Gopal, C. Turley, M.D.A. Rounsevell, O.P. Dube, J. Tarazona, A.A. Velichko (2007). "Executive Summary. In (book chapter): Ecosystems, their properties, goods and services. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds.)" (PDF). Book version: Cambridge University Press, Cambridge, UK. This version: IPCC website. p. 213. Retrieved 2010-04-26.{{cite web}}: CS1 maint: multiple names: authors list (link)
  76. ^ Schneider, S.H., S. Semenov, A. Patwardhan, I. Burton, C.H.D. Magadza, M. Oppenheimer, A.B. Pittock, A. Rahman, J.B. Smith, A. Suarez and F. Yamin (2007). "19.3.4 Ecosystems and biodiversity. In (book chapter): Assessing Key Vulnerabilities and the Risk from Climate Change. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds.)". Book version: Cambridge University Press, Cambridge, UK. This version: IPCC website. Retrieved 2010-04-26.{{cite web}}: CS1 maint: multiple names: authors list (link)
  77. ^ Verbruggen, A. (ed.) (2007). Glossary J-P. In (book section): Annex I. In: Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds.)). Print version: Cambridge University Press, Cambridge, U.K., and New York, N.Y., U.S.A.. This version: IPCC website. ISBN 9780521880114. Retrieved 2010-04-23. {{cite book}}: |author= has generic name (help)
  78. ^ World Bank (2010). Chapter 4: Energizing Development without Compromising the Climate. In: World Development Report 2010: Development and Climate Change. The International Bank for Reconstruction and Development / The World Bank, 1818 H Street NW, Washington DC 20433. p. 192. doi:10.1596/978-0-8213-7987-5. ISBN 9780821379875. Retrieved 2010-04-06.
  79. ^ a b IPCC (2007). 4. Adaptation and mitigation options. In (book section): Summary for Policymakers. In: 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 (Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)). Print version: IPCC, Geneva, Switzerland. This version: IPCC website. ISBN 9291691224. Retrieved 2010-04-26.
  80. ^ Smit, B. and O. Pilifosova. Lead Authors: I. Burton, B. Challenger, S. Huq, R.J.T. Klein, G. Yohe. Contributing Authors: N. Adger, T. Downing, E. Harvey, S. Kane, M. Parry, M. Skinner, J. Smith, J. Wandel. Review Editors: A. Patwardhan and J.-F. Soussana (2001). 18.2.3. Adaptation Types and Forms. In (book chapter): Adaptation to Climate Change in the Context of Sustainable Development and Equity. In: Climate Change 2001: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change (J.J. McCarthy, O.F. Canziani, N.A. Leary, D.J. Dokken, K.S. White (eds.)). Print version: Cambridge University Press, Cambridge, U.K., and New York, N.Y., U.S.A.. This version: GRID-Arendal website. ISBN 0521807689. Retrieved 2010-01-10. {{cite book}}: |author= has generic name (help)CS1 maint: multiple names: authors list (link)
  81. ^ Barker, T., I. Bashmakov, A. Alharthi, M. Amann, L. Cifuentes, J. Drexhage, M. Duan, O. Edenhofer, B. Flannery, M. Grubb, M. Hoogwijk, F. I. Ibitoye, C. J. Jepma, W.A. Pizer, K. Yamaji (2007). 11.2.2 Ocean fertilization and other geo-engineering options. In (book chapter): Mitigation from a cross-sectoral perspective. In: Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)). Print version: Cambridge University Press, Cambridge, U.K., and New York, N.Y., U.S.A.. This version: IPCC website. ISBN 9780521880114. Retrieved 2010-04-05.{{cite book}}: CS1 maint: multiple names: authors list (link)
  82. ^ IPCC (2007). C. Mitigation in the short and medium term (until 2030). In (book section): Summary for Policymakers. In: Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)). Print version: Cambridge University Press, Cambridge, U.K., and New York, N.Y., U.S.A.. This version: IPCC website. ISBN 9780521880114. Retrieved 2010-05-15.
  83. ^ UNFCCC (n.d.). "Essential Background". UNFCCC website. Retrieved 2010-05-18.
  84. ^ UNFCCC (n.d.). "Full text of the Convention, Article 2". UNFCCC website. Retrieved 2010-05-18.
  85. ^ UNFCCC (n.d.). "Full text of the Convention, start". UNFCCC website. Retrieved 2010-05-18.
  86. ^ a b Liverman, D.M. (2008). "Conventions of climate change: constructions of danger and the dispossession of the atmosphere" (PDF). Journal of Historical Geography. 35: 12–14. doi:10.1016/j.jhg.2008.08.008. Retrieved 2009-08-08.
  87. ^ UNFCCC (2007). "Compilation and synthesis of fourth national communications. Executive summary. Note by the secretariat. Document code: FCCC/SBI/2007/INF.6". United Nations Office at Geneva, Switzerland. p. 11. Retrieved 2010-05-17. {{cite web}}: Unknown parameter |day= ignored (help); Unknown parameter |month= ignored (help)
  88. ^ UNFCCC (2005). "Sixth compilation and synthesis of initial national communications from Parties not included in Annex I to the Convention. Note by the secretariat. Executive summary. Document code: FCCC/SBI/2005/18". United Nations Office at Geneva, Switzerland. p. 6. Retrieved 2010-05-17. {{cite web}}: Unknown parameter |day= ignored (help); Unknown parameter |month= ignored (help)
  89. ^ Müller, B. (2010). Copenhagen 2009: Failure or final wake-up call for our leaders? EV 49 (PDF). Dr Benito Müller's web page on the Oxford Institute for Energy Studies website. p. i. ISBN 978190755046. Retrieved 2010-05-18. {{cite book}}: Check |isbn= value: length (help); Unknown parameter |month= ignored (help)
  90. ^ UNFCCC (2010). "Decision 2/CP. 15 Copenhagen Accord. In: Report of the Conference of the Parties on its fifteenth session, held in Copenhagen from 7 to 19 December 2009. Addendum. Part Two: Action taken by the Conference of the Parties at its fifteenth session" (PDF). United Nations Office at Geneva, Switzerland. p. 5. Retrieved 2010-05-17. {{cite web}}: Unknown parameter |day= ignored (help); Unknown parameter |month= ignored (help)
  91. ^ Rogner, H.-H., D. Zhou, R. Bradley. P. Crabbé, O. Edenhofer, B.Hare, L. Kuijpers, M. Yamaguchi (2007). "Executive Summary. In (book chapter): Introduction. In: Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds))". Print version: Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Web version: IPCC website. Retrieved 2010-05-05.{{cite web}}: CS1 maint: multiple names: authors list (link)
  92. ^ Banuri, T., K. Göran-Mäler, M. Grubb, H.K. Jacobson and F. Yamin (1996). Equity and Social Considerations. In: 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 (J.P. Bruce, H. Lee and E.F. Haites, (eds.)) (PDF). This version: Printed by Cambridge University Press, Cambridge, U.K., and New York, N.Y., U.S.A.. PDF version: IPCC website. p. 87. doi:10.2277/0521568544. ISBN 9780521568548.{{cite book}}: CS1 maint: multiple names: authors list (link)
  93. ^ Banuri et al., 1996, p. 83
  94. ^ a b c Banuri et al., 1996, pp. 94-95
  95. ^ Grubb, M. (July–September 2003). "The Economics of the Kyoto Protocol" (PDF). World Economics. 4 (3): 144. Retrieved 2010-03-25.{{cite journal}}: CS1 maint: date format (link)
  96. ^ PBL (2009). "Global CO2 emissions: annual increase halves in 2008". Netherlands Environmental Assessment Agency (PBL) website. Retrieved 2010-05-05. {{cite web}}: Unknown parameter |day= ignored (help); Unknown parameter |month= ignored (help)
  97. ^ IEA (2005). "Energy Policies of IEA Countries - Australia- 2005 Review". International Energy Agency (IEA), Head of Publications Service, 9 rue de la Fédération, 75739 Paris Cedex 15, France. p. 51. Retrieved 2010-04-29. {{cite web}}: line feed character in |publisher= at position 65 (help)
  98. ^ a b Dessai, S. (2001). "The climate regime from The Hague to Marrakech: Saving or sinking the Kyoto Protocol? Tyndall Centre Working Paper 12". Tyndall Centre website. pp. 5–6. Retrieved 2010-05-05.
  99. ^ UNFCCC (2009). "Report of the in-depth review of the fourth national assessment communication of Australia". United Nations Office at Geneva, Switzerland. p. 3. Retrieved 2010-05-05. {{cite web}}: Unknown parameter |day= ignored (help); Unknown parameter |month= ignored (help)
  100. ^ Pelham, Brett (2009-04-22). "Awareness, Opinions About Global Warming Vary Worldwide". Gallup. Retrieved 2009-07-14.
  101. ^ "Summary of Findings". Little Consensus on Global Warming. Partisanship Drives Opinion. Pew Research Center. 2006-07-12. Retrieved 2007-04-14.
  102. ^ More in Europe worry about climate than in U.S., poll shows - Health & Science - International Herald Tribune
  103. ^ a b NRC, 2008, p. 2
  104. ^ Wallace, D. and J. Houghton (2005). "A guide to facts and fictions about climate change". UK Royal Society website. pp. 3–4. Retrieved 2010-05-05. {{cite web}}: Unknown parameter |month= ignored (help)
  105. ^ Academia Brasileira de Ciéncias (Brazil), Royal Society of Canada, Chinese Academy of Sciences, Académie des Sciences (France), Deutsche Akademie der Naturforscher Leopoldina (Germany), Indian National Science Academy, Accademia Nazionale dei Lincei (Italy), Science Council of Japan, Academia Mexicana de Ciencias, Russian Academy of Sciences, Academy of Science of South Africa, Royal Society (United Kingdom), National Academy of Sciences (United States of America) (2009). "G8+5 Academies' joint statement: Climate change and the transformation of energy technologies for a low carbon future" (PDF). US National Academies website. Retrieved 2010-05-05. {{cite web}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  106. ^ Weart, S. (2009). "The Public and Climate Change (cont. – since 1980). Section: After 1988". American Institute of Physics website. Retrieved 2010-05-05. {{cite web}}: Unknown parameter |month= ignored (help)
  107. ^ SEPP (n.d.). "Frequently Asked Questions About Climate Change". Science & Environmental Policy Project (SEPP) website. Retrieved 2010-05-05.
  108. ^ Begley, Sharon (2007-08-13). "The Truth About Denial". Newsweek. Retrieved 2007-08-13.
  109. ^ Adams, David (2006-09-20). "Royal Society tells Exxon: stop funding climate change denial". The Guardian. Retrieved 2007-08-09.
  110. ^ "Exxon cuts ties to global warming skeptics". MSNBC. 2007-01-12. Retrieved 2007-05-02.
  111. ^ Sandell, Clayton (2007-01-03). "Report: Big Money Confusing Public on Global Warming". ABC. Retrieved 2007-04-27.
  112. ^ "New Report Provides Authoritative Assessment of National, Regional Impacts of Global Climate Change" (PDF) (Press release). U.S. Global Change Research Program. June 6, 2009. Retrieved 2009-06-27.
  113. ^ Reuters (May 18, 2007). "Greenpeace: Exxon still funding climate skeptics". USA Today. Retrieved Jan 21, 2010. {{cite news}}: |author= has generic name (help)
  114. ^ "Global Warming Resolutions at U.S. Oil Companies Bring Policy Commitments from Leaders, and Record High Votes at Laggards" (Press release). Ceres. May 13, 2004. Retrieved 2010-03-04.
  115. ^ John T. Houghton (2004)."Global warming: the complete briefing". Cambridge University Press. p.326. ISBN 0521528747
  116. ^ "Once taboo, population enters climate debate". The Independent. December 5, 2009. Retrieved Jan 21, 2010.
  117. ^ IPCC (2007d). "Introduction. In (section): Synthesis Report. In (book): 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 (Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.))". Book version: IPCC, Geneva, Switzerland. This version: IPCC website. Retrieved 2010-04-26.

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