🤖 AI Summary
Atlantic大循環の崩壊が以前よりも著しく可能性が高いことが、最新の研究によって明らかになりました。この研究はGlobal Science Advances誌に発表され、気候モデルで最大の緩和を予測する那些が最も現実的であると判断されました。科学者たちは新しい見解を「非常に懸念すべき」ものとしています。大西洋経時熱帯移動循環（AMOC）は、既に1600年間で最弱とされているグローバル気候システムの一部です。アラスカの急速な温暖化による流れの遅延が主要因で、温かい水は密度が低く深層へ沈みにくくなるため、表面積雪が増加し、さらに沈降を遅らせるフィードバックループを作ります。
2100年までに42%から58%の緩和が予想され、これにより多くの人々が食糧生産に依存する熱帯雨量 belts の移動、ヨーロッパ西部への極端な寒冷化と夏場の乾燥、そして大西洋周辺の海面上昇に50-100cm増加が予想されます。この研究は海洋観測データとモデルを組み合わせることで実現しました。
An anonymous reader quotes a report from the Guardian: The critical Atlantic current system appears significantly more likely to collapse than previously thought after new research found that climate models predicting the biggest slowdown are the most realistic. Scientists called the new finding "very concerning" as a collapse would have catastrophic consequences for Europe, Africa and the Americas. The Atlantic meridional overturning circulation (Amoc) is a major part of the global climate system and was already known to be at its weakest for 1,600 years as a result of the climate crisis. Scientists spotted warning signs of a tipping point in 2021 and know that the Amoc has collapsed in the Earth's past.
Climate scientists use dozens of different computer models to assess the future climate. However, for the complex Amoc system, these produce widely varying results, ranging from some that indicate no further slowdown by 2100 to those suggesting a huge deceleration of about 65%, even when carbon emissions from fossil fuel burning are gradually cut to net zero. The research combined real-world ocean observations with the models to determine the most reliable, and this hugely reduced the spread of uncertainty. They found an estimated slowdown of 42% to 58% in 2100, a level almost certain to end in collapse.
The Amoc is a major part of the global climate system and brings sun-warmed tropical water to Europe and the Arctic, where it cools and sinks to form a deep return current. A collapse would shift the tropical rainfall belt on which many millions of people rely to grow their food, plunge western Europe into extreme cold winters and summer droughts, and add 50-100cm to already rising sea levels around the Atlantic. The slowdown has to do with the Arctic's rapidly rising temperatures from global warming. "Warmer water is less dense and therefore sinks into the depths more slowly," explains the Guardian. "This slowing allows more rainfall to accumulate in the salty surface waters, also making it less dense, and further slowing the sinking and forming an Amoc feedback loop."
The new research has been published in the journal Science Advances.
Read more of this story at Slashdot.
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