極端な気候下でも大西洋の転覆循環が続いている.
J A Baker1, M J Bell2, L C Jackson2
1Met Office, Exeter, UK. jonathan.baker@metoffice.gov.uk.
Nature
|February 26, 2025
まとめ
アトランティック南回流 (AMOC) は 今世紀には崩壊する可能性は低い. 南洋の上流は 極端な気候変動のシナリオでも AMOCを安定させ 崩壊を防ぎます
科学分野:
- 気候科学
- 海洋学
- 地球システム科学
背景:
- 大西洋の南回転循環 (AMOC) は,地球温暖化に不可欠です.
- 地球温暖化によるAMOCの弱体化が予測されているため,気候変動への影響が懸念されています.
- AMOCの弱体化と崩壊の可能性については不確実性があります.
研究 の 目的:
- 極端な気候条件下でのAMOCの回復力を調査する.
- 温室効果ガスと淡水の変化に反応して,AMOCの崩壊の可能性を決定する.
- AMOCを安定させるメカニズムを特定する.
主な方法:
- 極端な温室効果ガスと北大西洋の淡水圧迫をシミュレートした34の気候モデルを分析した.
- 南洋の上流の調査とAMOCの安定性への影響
- 南太平洋の逆転循環 (PMOC) が南洋の上昇を補う役割の評価
主要な成果:
- AMOCは34の気候モデル全体で 極端な強制への耐性を示しています
- 南大洋の上流は,弱まったAMOCを一貫して維持し,完全な崩壊を防ぐ.
- ほとんどのモデルでは補償的なPMOCが出現しますが,南洋の上流を完全に均衡させるには不十分です.
結論:
- AMOCの崩壊は,安定化メカニズムのため,今世紀では起こりそうにない.
- 南洋とインド太平洋の循環は,将来のAMOC変化を予測する重要な要因です.
- これらの循環を理解することは,生態系と海洋生物化学への影響を予測するために不可欠です.
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