大西洋海流の今後の可能性

Prof. Matt England @ProfMattEngland

Just published! Our new paper exploring the global climate response to a shutdown in the Atlantic Meridional Overturning Circulation. With @BryamOP and @AndreaTaschetto @ccrc_unsw @AntarcticSciAus nature.com/articles/s4155… (... my first ever🧵) pic.twitter.com/jEzXWk6Dpt

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Prof. Matt England @ProfMattEngland

In this study, we demonstrate the potential for far-reaching effects, including AMOC teleconnections to adjacent basins and into the Southern Hemisphere. It all starts with a build-up heat just south of the Equator in the Atlantic.... pic.twitter.com/L7U4Tqx9N0

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Prof. Matt England @ProfMattEngland

From there we show that an AMOC collapse can accelerate the Pacific trade winds and Walker circulation by leaving an excess of heat in the tropical South Atlantic, driving increased convection in the atmosphere there, and increased subsidence over the East Pacific pic.twitter.com/P6jfisLItV

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Prof. Matt England @ProfMattEngland

Further teleconnections include weakening of the Indian and South Atlantic subtropical highs, and deepening of the Amundsen Sea Low (ASL). See diagrams above or download a copy of our paper: nature.com/articles/s4155…

Prof. Matt England @ProfMattEngland

Motivation for our work is that global climate models predict a weakening // collapse of the AMOC, even before including the added effects of Greenland ice sheet melt. An AMOC slowdown would profoundly change distribution of heat in the Atlantic. But what about the atmosphere?

Prof. Matt England @ProfMattEngland

... and there is evidence that an AMOC slowdown is already well underway – e.g. see work led by @rahmstorf and colleagues, and others, such as nature.com/articles/nclim… nature.com/articles/s4156…

Prof. Matt England @ProfMattEngland

Might our climate of the past 30-40 years already contain an AMOC weakening signal in the Pacific and Antarctic regions? Maybe – Pacific trade winds have overall accelerated and the ASL has deepened in this time (although that is also consistent with IPO phase changes).

Prof. Matt England @ProfMattEngland

The mechanism we describe may have also played out during the LGM, when the AMOC was shallower and weaker, and when there was a relatively cold central equatorial Pacific and a stronger Walker circulation (e.g. see work by @mountain_gaucho and others) doi.org/10.1029/2010PA…

Prof. Matt England @ProfMattEngland

@danmiller999 @BryamOP @AndreaTaschetto @ccrc_unsw @AntarcticSciAus I’d defer to experts like @rahmstorf on AMOC projections but re. Antarctic ice sheet melt, a bigger threat there is subsurface ocean warming at the grounding lines. Which looks to be accelerating unfortunately

Prof. Matt England @ProfMattEngland

And here’s an open access link to a view-only version of the paper kindly provided free of charge by @NatureClimate rdcu.be/cO4rv

Prof. Matt England @ProfMattEngland

@Marcusgibson @BryamOP @AndreaTaschetto @ccrc_unsw @AntarcticSciAus Haha always happy to share reprint ☺️That’s an interesting point. Our tropical Pacific upwelling increases, but there’d be overall less nutrients being brought up from the abyss. Not sure which effect would prevail, I suspect Schmittner’s. We didn’t include BGC so cannot resolve

Prof. Matt England @ProfMattEngland

@PatrickAMazza @BryamOP @AndreaTaschetto @ccrc_unsw @AntarcticSciAus Good question! We find a more La Niña-like climate in response to AMOC shutdown. We have a follow-up study that goes into ENSO response in more detail. Will post about that when it’s ready

Prof. Matt England @ProfMattEngland

@grant_farquhar @BryamOP @AndreaTaschetto @ccrc_unsw @AntarcticSciAus Yes correct; AMOC slowdown linked to past ice age cycles, with evidence of the same teleconnection to the Pacific also occurring, consistent with our simulations

ギズモード・ジャパン @gizmodojapan

大西洋の大きい海流が止まってしまうと、世界規模の大災害が始まる dlvr.it/SSQ9V5

気候変動の向こう側 🇵🇸🇺🇦🏳️‍🌈 @Beyond_Climate

書きました。スローダウンが始まっている大西洋南北熱塩循環（AMOC）が、もしも止まってしまったら？『デイ・アフター・トゥモロー』「ヤンガードリアス期」の世界ですよね。⇒ 大西洋の大きい海流が止まってしまうと、世界規模の大災害が始まる gizmodo.jp/2022/06/amoc-a… #気候変動