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[[File:Sgubin2017 spg amoc collapse.jpg|thumb|Modelled 21st century warming under the [[Representative Concentration Pathway#RCP 4.5|"intermediate" climate change scenario]] (top). The potential collapse of the subpolar gyre in this scenario (middle). The collapse of the entire AMOC (bottom).]]
{{See also|Tipping points in the climate system}}
Unlike the [[AMOC]], the observations of Labrador Sea outflow showed no negative trend from 1997 to 2009,<ref>{{Cite journal |last1=Fischer |first1=Jürgen |last2=Visbeck |first2=Martin |last3=Zantopp |first3=Rainer |last4=Nunes |first4=Nuno |date=31 December 2010 |title=Interannual to decadal variability of outflow from the Labrador Sea
Some [[climate model]]s indicate that the deep convection in [[Labrador Sea|Labrador]]-[[Irminger Sea|Irminger]] Seas could collapse under certain [[global warming]] scenarios, which would then collapse the entire circulation in the North [[subpolar gyre]]. It is considered unlikely to recover even if the temperature is returned to a lower level, making it an example of a climate tipping point. This would result in rapid cooling, with implications for economic sectors, agriculture industry, water resources and energy management in Western Europe and the East Coast of the United States.<ref>{{cite journal|title=Abrupt cooling over the North Atlantic in modern climate models|journal=Nature Communications|volume=8|doi=10.1038/ncomms14375|pmid=28198383|pmc=5330854|author=Sgubin |display-authors=etal |year=2017 |bibcode=
A 2021 study found that this collapse occurs in only four [[CMIP6]] models out of 35 analyzed. However, only 11 models out of 35 can simulate North Atlantic Current with a high degree of accuracy, and this includes all four models which simulate collapse of the subpolar gyre. As the result, the study estimated the risk of an abrupt cooling event over Europe caused by the collapse of the current at 36.4%, which is lower than the 45.5% chance estimated by the previous generation of models <ref>{{Cite journal |last1=Swingedouw |first1=Didier |last2=Bily |first2=Adrien |last3=Esquerdo |first3=Claire |last4=Borchert |first4=Leonard F. |last5=Sgubin |first5=Giovanni |last6=Mignot |first6=Juliette |last7=Menary |first7=Matthew |date=2021 |title=On the risk of abrupt changes in the North Atlantic subpolar gyre in CMIP6 models |url=https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/nyas.14659 |journal=Annals of the New York Academy of Sciences |volume=1504 |issue=1 |pages=187–201 |doi=10.1111/nyas.14659|pmid=34212391 |bibcode=2021NYASA1504..187S |s2cid=235712017 |hdl=10447/638022 |hdl-access=free }}</ref> In 2022, a paper suggested that previous disruption of subpolar gyre was connected to the [[Little Ice Age]].<ref>{{Cite journal |last1=Arellano-Nava |first1=Beatriz |last2=Halloran |first2=Paul R. |last3=Boulton |first3=Chris A. |last4=Scourse |first4=James |last5=Butler |first5=Paul G. |last6=Reynolds |first6=David J. |last7=Lenton |first7=Timothy |date=25 August 2022 |title=Destabilisation of the Subpolar North Atlantic prior to the Little Ice Age |journal=Nature Communications |volume=13 |issue=1 |page=5008 |doi=10.1038/s41467-022-32653-x |pmid=36008418 |pmc=9411610 |bibcode=2022NatCo..13.5008A }}</ref>
A 2022 [[Science Magazine]] review study on climate tipping points noted that in the scenarios where this convection collapses, it is most likely to be triggered by 1.8 degrees of global warming. However, model differences mean that the required warming may be as low as 1.1 degrees or as high as 3.8 degrees. Once triggered, the collapse of the current would most likely take 10 years from start to end, with a range between 5 and 50 years. The loss of this convection is estimated to lower the global temperature by up to 0.5 degrees, while the [https://upload.wikimedia.org/wikipedia/commons/thumb/c/cd/Sgubin2017_spg_amoc_collapse.jpg/220px-Sgubin2017_spg_amoc_collapse.jpg average temperature in certain regions of the North Atlantic decreases by around 3 degrees]. There are also substantial impacts on regional [[precipitation]].<ref>{{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 }}</ref><ref>{{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}}</ref>
A 2023 study warns that the collapse could already happen by mid century.<ref>{{Cite journal |last1=Ditlevsen |first1=Peter|last2=Ditlevsen |first2=Susanne |date=25 July 2023 |title=Warning of a forthcoming collapse of the Atlantic meridional overturning circulation |url=https://www.nature.com/articles/s41467-023-39810-w |journal=Nature |language=en |volume=14 |issue=1 |pages=4254 |doi=10.1038/s41467-023-39810-w |pmid=37491344|arxiv=2304.09160 }}</ref>
== See also ==
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