Editing Climate (section)

==Climate change==
[[File:Change in Average Temperature With Fahrenheit.svg|thumb|upright=1.35|right|Surface air temperature change over the past 50 years.<ref>{{Cite web |title=GISS Surface Temperature Analysis (v4) |url=https://data.giss.nasa.gov/gistemp/maps/index_v4.html |access-date=12 January 2024 |website=NASA}}</ref>]]
[[File:Global Temperature And Forces With Fahrenheit.svg|thumb|upright=1.35|right|Observed temperature from NASA<ref name="nasa temperatures">{{cite web |title=Global Annual Mean Surface Air Temperature Change |url=https://data.giss.nasa.gov/gistemp/graphs_v4/ |publisher=NASA |access-date=23 February 2020 |archive-date=16 April 2020 |archive-url=https://web.archive.org/web/20200416074510/https://data.giss.nasa.gov/gistemp/graphs_v4/ |url-status=live }}.</ref> vs the 1850–1900 average used by the IPCC as a pre-industrial baseline.<ref name="ipcc pre industrial baseline">{{harvnb|IPCC AR5 SYR Glossary|2014|page=124}}.</ref> The primary driver for increased global temperatures in the industrial era is human activity, with natural forces adding variability.<ref name="USGCRP Chapter 3 Figure 3-1 panel 2">{{harvnb|USGCRP Chapter 3|2017}} [https://science2017.globalchange.gov/chapter/3#fig-3-1 Figure 3.1 panel 2] {{Webarchive|url=https://web.archive.org/web/20180409042234/https://science2017.globalchange.gov/chapter/3/#fig-3-1 |date=2018-04-09 }}, [https://science2017.globalchange.gov/chapter/3#fig-3-3 Figure 3.3 panel 5] {{Webarchive|url=https://web.archive.org/web/20180409042234/https://science2017.globalchange.gov/chapter/3/#fig-3-3 |date=2018-04-09 }}.</ref>]]
{{Main|Climate change}}
{{See also|Global temperature record|List of weather records|Extreme event attribution}}
Climate change is the variation in global or regional climates over time.<ref>{{Cite web |title=Climate Change {{!}} National Geographic Society |url=https://education.nationalgeographic.org/resource/climate-change |access-date=2022-06-28 |website=Education {{!}} National Geographic Society |archive-date=2022-07-30 |archive-url=https://web.archive.org/web/20220730092254/https://education.nationalgeographic.org/resource/climate-change/ |url-status=live }}</ref> It reflects changes in the variability or average state of the atmosphere over time scales ranging from decades to millions of years. These changes can be caused by processes internal to the [[Earth]], external forces (e.g. variations in sunlight intensity) or human activities, as found recently.<ref>Arctic Climatology and Meteorology. [http://nsidc.org/arcticmet/glossary/climate_change.html Climate change.] {{webarchive|url=https://web.archive.org/web/20100118201820/http://nsidc.org/arcticmet/glossary/climate_change.html |date=2010-01-18 }} Retrieved on 2008-05-19.</ref><ref name="NYT-20151128-jg">{{cite news |last=Gillis |first=Justin |title=Short Answers to Hard Questions About Climate Change |url=https://www.nytimes.com/interactive/2015/11/28/science/what-is-climate-change.html |date=28 November 2015 |work=[[The New York Times]] |access-date=29 November 2015 |archive-date=22 September 2020 |archive-url=https://web.archive.org/web/20200922100003/https://www.nytimes.com/interactive/2015/11/28/science/what-is-climate-change.html/ |url-status=live }}</ref>  Scientists have identified [[Earth's Energy Imbalance]] (EEI) to be a fundamental metric of the status of global change.<ref>{{cite journal |last1=von Schuckman |first1=K. |last2=Palmer |first2=M. D. |last3=Trenberth |first3=K. E. |last4=Cazenave |first4=A. |last5=Chambers |first5=D. |last6=Champollion |first6=N. |last7=Hansen |first7=J. |last8=Josey |first8=S. A. |last9=Loeb |first9=N |last10=Mathieu |first10=P. P. |last11=Meyssignac |first11=B. |last12=Wild |first12=N. |title=An imperative to monitor Earth's energy imbalance |journal=Nature Climate Change |date=27 January 2016 |doi=10.1038/NCLIMATE2876 |volume=6 |issue=2 |pages=138–144 |bibcode=2016NatCC...6..138V |url=http://nora.nerc.ac.uk/id/eprint/512751/1/vonSchuckmannPostprint.pdf }}</ref>

In recent usage, especially in the context of [[environmental policy]], the term "climate change" often refers only to changes in modern climate, including the rise in average surface [[temperature]] known as [[global warming]]. In some cases, the term is also used with a presumption of human causation, as in the [[United Nations]] [[UNFCCC|Framework Convention on Climate Change]] (UNFCCC). The UNFCCC uses "climate variability" for non-human caused variations.<ref>{{cite web|url=http://www.grida.no/climate/ipcc_tar/wg1/518.htm |title=Glossary |work=Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change |access-date=2008-05-22 |date=2001-01-20 |publisher=[[Intergovernmental Panel on Climate Change]] |url-status=dead |archive-url=https://web.archive.org/web/20170126132100/http://www.grida.no/climate/ipcc_tar/wg1/518.htm |archive-date=2017-01-26 }}</ref>

Earth has undergone periodic climate shifts in the past, including four major [[ice age]]s. These consist of glacial periods where conditions are colder than normal, separated by [[interglacial]] periods. The accumulation of snow and ice during a glacial period increases the surface [[albedo]], reflecting more of the Sun's energy into space and maintaining a lower atmospheric temperature. Increases in [[greenhouse gas]]es, such as by [[Volcanic impacts on the oceans|volcanic activity]], can increase the global temperature and produce an interglacial period. Suggested causes of ice age periods include the positions of the [[continent]]s, variations in the Earth's orbit, changes in the solar output, and volcanism.<ref>Illinois State Museum (2002). [http://www.museum.state.il.us/exhibits/ice_ages/ Ice Ages.] {{Webarchive|url=https://web.archive.org/web/20100326000124/http://www.museum.state.il.us/exhibits/ice_ages/ |date=2010-03-26 }} Retrieved on 2007-05-15.</ref> However, these naturally caused changes in climate occur on a much slower time scale than the present rate of change which is caused by the emission of greenhouse gases by human activities.<ref>{{Cite journal |last1=Joos |first1=Fortunat |last2=Spahni |first2=Renato |date=2008-02-05 |title=Rates of change in natural and anthropogenic radiative forcing over the past 20,000 years |journal=Proceedings of the National Academy of Sciences |language=en |volume=105 |issue=5 |pages=1425–1430 |doi=10.1073/pnas.0707386105 |issn=0027-8424 |pmc=2234160 |pmid=18252830|bibcode=2008PNAS..105.1425J |doi-access=free }}</ref>

According to the EU's Copernicus Climate Change Service, average global air temperature has passed 1.5C of warming the period from February 2023 to January 2024.<ref>{{Cite news |date=2024-02-08 |title=World's first year-long breach of key 1.5C warming limit |url=https://www.bbc.com/news/science-environment-68110310 |access-date=2024-02-10 |language=en-GB}}</ref>