北極圏の気候と極端気象が加速する新メカニズムを解明(Increasing Heat is Super-Charging Arctic Climate and Weather Extremes)

2025-10-21 ノースカロライナ州立大学(NCState)

ノースカロライナ州立大学の研究者を中心とする国際チームは、北極の気候変動が新たな「臨界状態」に達し、極端気象が加速していることを明らかにした。2000年以降、大気・海洋・氷床の各システムで極端事象が急増しており、熱波発生確率は20%、大西洋層の高温事象76%、海氷損失83%、グリーンランド氷床融解68%増加した。研究は「推進・誘発メカニズム」を提示し、長期的温暖化がシステムを不安定化させ、内部変動が極端現象を誘発する仕組みを示した。大規模な気圧配置や海洋循環が熱と水蒸気の北極流入を強化し、氷床温度上昇とさらなる極端化を引き起こしている。今後も人為的温暖化が続けば、北極の夏季無氷化が今世紀半ばに現実化する可能性が高いと警告している。

<関連情報>

変化する北極の気象と気候の極端 Weather and climate extremes in a changing Arctic

Xiangdong Zhang,Timo Vihma,Annette Rinke,G. W. K. Moore,Han Tang,Cecilia Äijälä,Alice DuVivier,Jianbin Huang,Laura Landrum,Chao Li,Jing Zhang,Linette Boisvert,Bin Cheng,Judah Cohen,Dörthe Handorf,Edward Hanna,Katharina Hartmuth,Marius O. Jonassen,Yong Luo,Sonja Murto,James E. Overland,Chelsea Parker,William Perrie,Kirstin Schulz,… Minghong Zhang
Nature Reviews Earth & Environment  Published:21 October 2025
DOI:https://doi.org/10.1038/s43017-025-00724-4

北極圏の気候と極端気象が加速する新メカニズムを解明(Increasing Heat is Super-Charging Arctic Climate and Weather Extremes)

Abstract

Weather and climate extremes are increasingly occurring in the Arctic. In this Review, we evaluate historical and projected changes in rare Arctic extremes across the atmosphere, cryosphere and ocean and elucidate their driving mechanisms. Clear shifts occur in mean and extreme distributions after ~2000. For instance, pre-2000 to post-2000 observational probabilities of 1.5 standard deviation events increase by 20% for atmospheric heat waves, 76.7% for Atlantic layer warm events, 83.5% for Arctic sea ice loss and 62.9% for Greenland Ice Sheet melt extent — in many cases, low probability, rare extreme events in the early period become the norm in the latter period. These observed changes can be explained using a ‘pushing and triggering’ concept, representing interplay between external forcing and internal variability: long-term warming destabilizes the climate system and ‘pushes’ it to a new state, allowing subsequent variability associated with large-scale atmosphere–ocean–ice interactions and synoptic systems to ‘trigger’ extreme events over different timescales. Ongoing anthropogenic warming is expected to further increase the frequency and magnitude of extremes, such that simulated probabilities of 1.5 standard deviation events increase by 72.6% for atmospheric heat waves, 68.7% for Atlantic layer warm events and 93.3% for Greenland Ice Sheet melt rate between historic (1984–2014) and future (2069–2099) periods under a very high emission scenario. Future research should prioritize the development of physically based metrics, enhance high-resolution observation and modelling capabilities and improve understanding of multiscale Arctic climate drivers.

1702地球物理及び地球化学
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