Editing Greenland (section)

===Climate change===
{{See also|Climate change in the Arctic|Sea level rise}}{{Multiple image
| image1            = Greenland Meltdown 08072012 12072012.jpg
| image2            = Höning 2023 GIS thresholds.jpg
| caption1          = 2012 NASA graphics show the extent of a then-record melting event
| caption2          = Potential equilibrium states of the ice sheet in response to different equilibrium carbon dioxide concentrations in parts per million, 2023<ref name="Höning2023">{{Cite journal |last1=Höning |first1=Dennis |last2=Willeit |first2=Matteo |last3=Calov |first3=Reinhard |last4=Klemann |first4=Volker |last5=Bagge |first5=Meike |last6=Ganopolski |first6=Andrey |date=27 March 2023 |title=Multistability and Transient Response of the Greenland Ice Sheet to Anthropogenic CO2 Emissions |journal=Geophysical Research Letters |volume=50 |issue=6 |page=e2022GL101827 |doi=10.1029/2022GL101827 |s2cid=257774870}}</ref>
}}

The Greenland ice sheet always loses some mass from [[ice calving]] at its coasts, but it used to balance this on average by the accumulation of snowfall.<ref name="Noël2021">{{Cite journal |last1=Noël |first1=B. |last2=van Kampenhout |first2=L. |last3=Lenaerts |first3=J. T. M. |last4=van de Berg |first4=W. J. |last5=van den Broeke |first5=M. R. |date=19 January 2021 |title=A 21st Century Warming Threshold for Sustained Greenland Ice Sheet Mass Loss |journal=Geophysical Research Letters |volume=48 |issue=5 |page=e2020GL090471 |doi=10.1029/2020GL090471 |bibcode=2021GeoRL..4890471N |hdl=2268/301943 |s2cid=233632072 |hdl-access=free}}</ref> However, Greenland has been warming since around 1900,<ref>{{Cite journal |last1=Kjeldsen |first1=Kristian K. |last2=Korsgaard |first2=Niels J. |last3=Bjørk |first3=Anders A. |last4=Khan |first4=Shfaqat A. |last5=Box |first5=Jason E. |last6=Funder |first6=Svend |last7=Larsen |first7=Nicolaj K. |last8=Bamber |first8=Jonathan L. |last9=Colgan |first9=William |last10=van den Broeke |first10=Michiel |last11=Siggaard-Andersen |first11=Marie-Louise |last12=Nuth |first12=Christopher |last13=Schomacker |first13=Anders |last14=Andresen |first14=Camilla S. |last15=Willerslev |first15=Eske |last16=Kjær |first16=Kurt H. |date=16 December 2015 |title=Spatial and temporal distribution of mass loss from the Greenland Ice Sheet since AD 1900 |journal=Nature |language=en |volume=528 |issue=7582 |pages=396–400 |doi=10.1038/nature16183 |pmid=26672555 |bibcode=2015Natur.528..396K |hdl=1874/329934 |s2cid=4468824 |hdl-access=free}}</ref> and starting in the 1980s, the losses became larger than the gains.<ref name="Mouginot2019">{{cite journal |last1=Mouginot |first1=Jérémie |last2=Rignot |first2=Eric |last3=Bjørk |first3=Anders A. |last4=van den Broeke |first4=Michiel |last5=Millan |first5=Romain |last6=Morlighem |first6=Mathieu |last7=Noël |first7=Brice |last8=Scheuchl |first8=Bernd |last9=Wood |first9=Michael |title=Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018 |journal=Proceedings of the National Academy of Sciences |date=20 March 2019 |volume=116 |issue=19 |pages=9239–9244 |doi=10.1073/pnas.1904242116 |pmid=31010924 |pmc=6511040 |bibcode=2019PNAS..116.9239M |doi-access=free}}</ref> After 1996, Greenland has not had a single year when it did not lose mass on average.<ref name="CB2022">{{cite web |last1=Stendel |first1=Martin |last2=Mottram |first2=Ruth |date=22 September 2022 |title=Guest post: How the Greenland ice sheet fared in 2022 |url=https://www.carbonbrief.org/guest-post-how-the-greenland-ice-sheet-fared-in-2022/ |website=[[Carbon Brief]] |access-date=2022-10-22 |archive-date=22 October 2022 |archive-url=https://web.archive.org/web/20221022153851/https://www.carbonbrief.org/guest-post-how-the-greenland-ice-sheet-fared-in-2022/ |url-status=live}}</ref> In the 2010s, the Greenland ice sheet melted at its fastest rate during at least the past 12,000 years, and is on track to exceed that later in the century.<ref name="Briner2020">{{cite journal |last1=Briner |first1=Jason P. |last2=Cuzzone |first2=Joshua K. |last3=Badgeley |first3=Jessica A. |last4=Young |first4=Nicolás E. |last5=Steig |first5=Eric J. |last6=Morlighem |first6=Mathieu |last7=Schlegel |first7=Nicole-Jeanne |last8=Hakim |first8=Gregory J. |last9=Schaefer |first9=Joerg M. |last10=Johnson |first10=Jesse V. |last11=Lesnek |first11=Alia J. |last12=Thomas |first12=Elizabeth K. |last13=Allan |first13=Estelle |last14=Bennike |first14=Ole |last15=Cluett |first15=Allison A. |last16=Csatho |first16=Beata |last17=de Vernal |first17=Anne |last18=Downs |first18=Jacob |last19=Larour |first19=Eric |last20=Nowicki |first20=Sophie |date=30 September 2020 |title=Rate of mass loss from the Greenland Ice Sheet will exceed Holocene values this century |journal=Nature |volume=586 |issue=7827 |pages=70–74 |doi=10.1038/s41586-020-2742-6 |pmid=32999481 |bibcode=2020Natur.586...70B |s2cid=222147426}}</ref> In 2012, 2019 and 2021, so-called "massive melting events" occurred, when practically the entire surface of the ice sheet was melting and no accumulation took place.<ref>{{cite web |date=23 September 2013 |title=Greenland enters melt mode |url=http://www.sciencenews.org/view/generic/id/342767/title/Greenland_enters_melt_mode |work=Science News |access-date=14 August 2012 |archive-date=5 August 2012 |archive-url=https://web.archive.org/web/20120805043523/http://www.sciencenews.org/view/generic/id/342767/title/Greenland_enters_melt_mode |url-status=live}}</ref><ref name="phys-Greenland">{{cite news |title=Record melt: Greenland lost 586 billion tons of ice in 2019 |url=https://phys.org/news/2020-08-greenland-lost-billion-tons-ice.html |access-date=6 September 2020 |work=phys.org |language=en |archive-date=13 September 2020 |archive-url=https://web.archive.org/web/20200913083740/https://phys.org/news/2020-08-greenland-lost-billion-tons-ice.html |url-status=live}}</ref><ref name="MeltEvents">{{Cite web |last=Barnes |first=Adam |date=9 August 2021 |title='Massive melting event' torpedoes billions of tons of ice the whole world depends on |url=https://thehill.com/changing-america/sustainability/climate-change/566950-massive-melting-event-torpedoes-billions-of |work=The Hill |quote=Ice cores show that these widespread melt events were really rare prior to the 21st century, but since then, we have had several melt seasons. |access-date=24 August 2021 |archive-date=25 August 2021 |archive-url=https://web.archive.org/web/20210825031801/https://thehill.com/changing-america/sustainability/climate-change/566950-massive-melting-event-torpedoes-billions-of |url-status=live}}</ref> During the 2021 event, rain fell at Greenland's highest point for the first time in recorded history, an event so unexpected that the research station at the summit had no [[rain gauge]]s for the occasion.<ref name="waPoRain">{{Cite news |last=Patel |first=Kasha |date=19 August 2021 |title=Rain falls at the summit of Greenland Ice Sheet for first time on record |url=https://www.washingtonpost.com/weather/2021/08/19/greenland-melt-august-summit-rain/ |newspaper=Washington Post |quote=Rain fell on and off for 13 hours at the station, but staff are not certain exactly how much rain fell...there are no rain gauges at the summit because no one expected it to rain at this altitude. |access-date=24 August 2021 |archive-date=19 August 2021 |archive-url=https://web.archive.org/web/20210819221317/https://www.washingtonpost.com/weather/2021/08/19/greenland-melt-august-summit-rain/ |url-status=live}}</ref>

As with the ice loss elsewhere, the melting of Greenland contributes to sea level rise. Between 2012 and 2017, this melting added an average of 0.68&nbsp;mm per year,<ref name="Shepherd2020">{{Cite journal |last1=Shepherd |first1=Andrew |last2=Ivins |first2=Erik |last3=Rignot |first3=Eric |last4=Smith |first4=Ben |last5=van den Broeke |first5=Michiel |last6=Velicogna |first6=Isabella |author-link6=Isabella Velicogna |last7=Whitehouse |first7=Pippa |last8=Briggs |first8=Kate |last9=Joughin |first9=Ian |last10=Krinner |first10=Gerhard |last11=Nowicki |first11=Sophie |date=12 March 2020 |title=Mass balance of the Greenland Ice Sheet from 1992 to 2018 |journal=Nature |language=en |volume=579 |issue=7798 |pages=233–239 |doi=10.1038/s41586-019-1855-2 |pmid=31822019 |hdl=2268/242139 |s2cid=219146922 |issn=1476-4687 |url=https://orbi.uliege.be/handle/2268/242139 |access-date=23 October 2022 |archive-date=23 October 2022 |archive-url=https://web.archive.org/web/20221023151210/https://orbi.uliege.be/handle/2268/242139 |url-status=live |hdl-access=free}}</ref> equal to 37% of sea level rise from land ice sources (excluding thermal expansion of water from the continual increase in the [[ocean heat content]]).<ref name="Bamber2018">{{cite journal |last1=Bamber |first1=Jonathan L |last2=Westaway |first2=Richard M |last3=Marzeion |first3=Ben |last4=Wouters |first4=Bert |title=The land ice contribution to sea level during the satellite era |journal=Environmental Research Letters |date=1 June 2018 |volume=13 |issue=6 |page=063008 |doi=10.1088/1748-9326/aac2f0 |bibcode=2018ERL....13f3008B |doi-access=free |hdl=1983/58218615-dedd-43a8-a8ea-79fb83130613 |hdl-access=free}}</ref> By the end of the century, the melting of Greenland alone will add between ~{{cvt|6|cm|in|frac=2}} if the temperature change is kept below {{convert|2|C-change|F-change}}, to around {{cvt|13|cm|in|frac=2}} if the most intense [[climate change scenario]] with ever-increasing [[greenhouse gas emissions]] is followed.<ref name="IPCC AR6 WG1 Ch.9">{{Cite book |last1=Fox-Kemper |first1=B. |last2=Hewitt |first2=H.T. |author2-link=Helene Hewitt |last3=Xiao |first3=C. |last4=Aðalgeirsdóttir |first4=G. |last5=Drijfhout |first5=S.S. |last6=Edwards |first6=T.L. |last7=Golledge |first7=N.R. |last8=Hemer |first8=M. |last9=Kopp |first9=R.E. |last10=Krinner |first10=G. |last11=Mix |first11=A. |date=2021 |editor-last=Masson-Delmotte |editor-first=V. |editor2-last=Zhai |editor2-first=P. |editor3-last=Pirani |editor3-first=A. |editor4-last=Connors |editor4-first=S.L. |editor5-last=Péan |editor5-first=C. |editor6-last=Berger |editor6-first=S. |editor7-last=Caud |editor7-first=N. |editor8-last=Chen |editor8-first=Y. |editor9-last=Goldfarb |editor9-first=L. |chapter=Chapter 9: Ocean, Cryosphere and Sea Level Change |title=Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |chapter-url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter09.pdf |publisher=Cambridge University Press, Cambridge, UK and New York, NY, US |access-date=22 October 2022 |archive-date=24 October 2022 |archive-url=https://web.archive.org/web/20221024162651/https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter09.pdf |url-status=live}}</ref>{{rp|1302}} Under this scenario, the worst case for Greenland melting could reach {{cvt|33|cm|in|frac=2}} of sea level rise equivalent.<ref name="Aschwanden2019">{{Cite journal |last1=Aschwanden |first1=Andy |last2=Fahnestock |first2=Mark A. |last3=Truffer |first3=Martin |last4=Brinkerhoff |first4=Douglas J. |last5=Hock |first5=Regine |last6=Khroulev |first6=Constantine |last7=Mottram |first7=Ruth |last8=Khan |first8=S. Abbas |date=19 June 2019 |title=Contribution of the Greenland Ice Sheet to sea level over the next millennium |journal=Science Advances |volume=5 |issue=6 |pages=218–222 |language=EN |doi=10.1126/sciadv.aav9396 |pmid=31223652 |pmc=6584365 |bibcode=2019SciA....5.9396A}}</ref> The large quantities of fresh [[meltwater]] also affect the [[Atlantic meridional overturning circulation]] (AMOC) by diluting key currents, slowing it down.<ref name=PhysorgJan2016>{{cite web |date=22 January 2016 |title=Melting Greenland ice sheet may affect global ocean circulation, future climate |url=http://phys.org/news/2016-01-greenland-ice-sheet-affect-global.html |publisher=Phys.org |access-date=25 January 2016 |archive-date=19 August 2023 |archive-url=https://web.archive.org/web/20230819184753/https://phys.org/news/2016-01-greenland-ice-sheet-affect-global.html |url-status=live}}</ref><ref>{{cite journal |last1=Yang |first1=Qian |last2=Dixon |first2=Timothy H. |last3=Myers |first3=Paul G. |last4=Bonin |first4=Jennifer |last5=Chambers |first5=Don |last6=van den Broeke |first6=M. R. |last7=Ribergaard |first7=Mads H. |last8=Mortensen |first8=John |title=Recent increases in Arctic freshwater flux affects Labrador Sea convection and Atlantic overturning circulation |journal=Nature Communications |date=22 January 2016 |volume=7 |page=10525 |doi=10.1038/ncomms10525 |pmid=26796579 |pmc=4736158 |bibcode=2016NatCo...710525Y}}</ref> Due to this meltwater input, the circulation may even collapse outright with widespread detrimental effects, although research suggests this is likely only if the highest possible warming is sustained for multiple centuries.<ref>{{Cite journal |last1=Bakker |first1=P |last2=Schmittner |first2=A |last3=Lenaerts |first3=JT |last4=Abe-Ouchi |first4=A |last5=Bi |first5=D |last6=van den Broeke |first6=MR |last7=Chan |first7=WL |last8=Hu |first8=A |last9=Beadling |first9=RL |last10=Marsland |first10=SJ |last11=Mernild |first11=SH |last12=Saenko |first12=OA |last13=Swingedouw |first13=D |last14=Sullivan |first14=A |last15=Yin |first15=J |date=11 November 2016 |title=Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting |journal=Geophysical Research Letters |volume=43 |issue=23 |pages=12,252–12,260 |doi=10.1002/2016GL070457 |bibcode=2016GeoRL..4312252B |hdl=10150/622754 |s2cid=133069692 |hdl-access=free}}</ref><ref>{{Cite book |last1=Canadell |first1=J.G. |last2=Monteiro |first2=P.M.S. |last3=Costa |first3=M.H. |last4=Cotrim da Cunha |first4=L. |last5=Cox |first5=P.M. |last6=Eliseev |first6=A.V. |last7=Henson |first7=S. |last8=Ishii |first8=M. |last9=Jaccard |first9=S. |last10=Koven |first10=C. |last11=Lohila |first11=A. |editor-last=Masson-Delmotte |editor-first=V. |editor2-last=Zhai |editor2-first=P. |editor3-last=Piran |editor3-first=A. |editor4-last=Connors |editor4-first=S.L. |editor5-last=Péan |editor5-first=C. |editor6-last=Berger |editor6-first=S. |editor7-last=Caud |editor7-first=N. |editor8-last=Chen |editor8-first=Y. |editor9-last=Goldfarb |editor9-first=L. |chapter=Global Carbon and Other Biogeochemical Cycles and Feedbacks |chapter-url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter05.pdf |title=Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |year=2021 |pages=673–816 |doi=10.1017/9781009157896.007 |bibcode=2021AGUFM.U13B..05K |access-date=20 March 2024 |archive-date=6 April 2023 |archive-url=https://web.archive.org/web/20230406183849/https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter05.pdf |url-status=live}}</ref>

Greenland's ice sheet has a volume of ~{{convert|2900000|km3|cumi|-3}}. This means that if it were all to melt, global sea level would increase by ~{{convert|7.4|m|ft|0|abbr=on}} from that event alone.<ref name="BBC2017">{{cite web |title=How Greenland would look without its ice sheet |date=14 December 2017 |url=https://www.bbc.com/news/science-environment-42260580 |publisher=[[BBC News]] |access-date=7 December 2023 |archive-date=7 December 2023 |archive-url=https://web.archive.org/web/20231207201039/https://www.bbc.com/news/science-environment-42260580 |url-status=live}}</ref> However, it also means that it will take at least 1,000 years for the ice sheet to disappear even with very high rates of global warming,<ref name="Aschwanden2019" /> and in around 10,000 years under lower rates of warming which still cross the threshold for the ice sheet's disappearance.<ref name="ArmstrongMcKay2022">{{Cite journal |last1=Armstrong McKay |first1=David |last2=Abrams |first2=Jesse |last3=Winkelmann |first3=Ricarda |last4=Sakschewski |first4=Boris |last5=Loriani |first5=Sina |last6=Fetzer |first6=Ingo |last7=Cornell |first7=Sarah |last8=Rockström |first8=Johan |last9=Staal |first9=Arie |last10=Lenton |first10=Timothy |date=9 September 2022 |title=Exceeding 1.5°C global warming could trigger multiple climate tipping points |url=https://www.science.org/doi/10.1126/science.abn7950 |journal=Science |language=en |volume=377 |issue=6611 |pages=eabn7950 |doi=10.1126/science.abn7950 |pmid=36074831 |hdl=10871/131584 |s2cid=252161375 |issn=0036-8075 |hdl-access=free |access-date=22 October 2022 |archive-date=14 November 2022 |archive-url=https://web.archive.org/web/20221114143835/https://www.science.org/doi/10.1126/science.abn7950 |url-status=live}}</ref><ref name="ArmstrongMcKay2022Explainer">{{Cite web |last=Armstrong McKay |first=David |date=9 September 2022 |title=Exceeding 1.5°C global warming could trigger multiple climate tipping points – paper explainer |url=https://climatetippingpoints.info/2022/09/09/climate-tipping-points-reassessment-explainer/ |access-date=2 October 2022 |website=climatetippingpoints.info |language=en |archive-date=18 July 2023 |archive-url=https://web.archive.org/web/20230718085705/https://climatetippingpoints.info/2022/09/09/climate-tipping-points-reassessment-explainer/ |url-status=live}}</ref> This threshold likely lies for between {{convert|1.7|C-change|F-change}} and {{convert|2.3|C-change|F-change}}. Reducing the warming back to {{convert|1.5|C-change|F-change}} or lower above preindustrial levels (such as through large-scale [[carbon dioxide removal]]) would arrest the losses, but still cause greater ultimate sea level rise than if the threshold had never been exceeded.<ref name="Bochow2023">{{cite journal |last1=Bochow |first1=Nils |last2=Poltronieri |first2=Anna |last3=Robinson |first3=Alexander |last4=Montoya |first4=Marisa |last5=Rypdal |first5=Martin |last6=Boers |first6=Niklas |date=18 October 2023 |title=Overshooting the critical threshold for the Greenland ice sheet |journal=Nature |volume=622 |issue=7983 |pages=528–536 |bibcode=2023Natur.622..528B |doi=10.1038/s41586-023-06503-9 |pmc=10584691 |pmid=37853149}}</ref> Further, {{convert|1.5|C-change|F-change}} itself appears to commit the Greenland ice sheet to {{cvt|1.4|m|ft|frac=2}} of sea level rise.<ref name="Christ2023">{{Cite journal |last1=Christ |first1=Andrew J. |last2=Rittenour |first2=Tammy M. |last3=Bierman |first3=Paul R. |last4=Keisling |first4=Benjamin A. |last5=Knutz |first5=Paul C. |last6=Thomsen |first6=Tonny B. |last7=Keulen |first7=Nynke |last8=Fosdick |first8=Julie C. |last9=Hemming |first9=Sidney R. |last10=Tison |first10=Jean-Louis |last11=Blard |first11=Pierre-Henri |last12=Steffensen |first12=Jørgen P. |last13=Caffee |first13=Marc W. |last14=Corbett |first14=Lee B. |last15=Dahl-Jensen |first15=Dorthe |last16=Dethier |first16=David P. |last17=Hidy |first17=Alan J. |last18=Perdrial |first18=Nicolas |last19=Peteet |first19=Dorothy M. |last20=Steig |first20=Eric J. |last21=Thomas |first21=Elizabeth K. |date=20 July 2023 |title=Deglaciation of northwestern Greenland during Marine Isotope Stage 11 |journal=Science |volume=381 |issue=6655 |pages=330–335 |doi=10.1126/science.ade4248 |pmid=37471537 |bibcode=2023Sci...381..330C |osti=1992577 |s2cid=259985096}}</ref>

A study published in January 2025 in the ''[[Proceedings of the National Academy of Sciences of the United States of America|Proceedings of the National Academy of Sciences]]'' reported an "abrupt, coherent, climate-driven transformation" from "blue" (more transparent) to "brown" (less transparent) states of lakes in Greenland after a season of both record heat and rainfall drove a [[Tipping points in the climate system|state change]] in these systems.<ref name=PNAS_20250121/> This change was said to alter "numerous physical, chemical, and biological lake features", and the state changes were said to be unprecedented.<ref name=PNAS_20250121>{{cite journal |last1=Saros |first1=Jasmine E. |last2=Hazukova |first2=Vaclava |last3=Northington |first3=Robert M. |last4=McGowan |first4=Suzanne |title=Abrupt transformation of West Greenland lakes following compound climate extremes associated with atmospheric rivers |journal=Proceedings of the National Academy of Sciences of the United States of America |date=21 January 2025 |volume=122 |issue=4 |page=e2413855122 |doi=10.1073/pnas.2413855122 |pmid=39835905 |pmc=11789078 |bibcode=2025PNAS..12213855S}}</ref>