海洋温暖化が南極氷河流動の加速を引き起こす(Ocean Warming Drives Acceleration of Glacier Flow in Antarctica)

2026-04-17 中国科学院(CAS)

中国科学院西北生態環境資源研究院の研究チームは、南極半島ベアスコチェア湾の氷河加速の主因が上層海洋の温暖化であることを明らかにした。2015~2025年に101氷河の流速を高精度で観測した結果、2018年以降に広範で持続的な加速が確認され、気候システムの転換点の可能性が示された。従来想定されていた融解水ではなく、水深0~300mの海洋熱が氷河流動を支配する主要因と判明した。また氷河は外部温暖化への感受性が高まり、構造的脆弱性も増大している。本研究は氷床動態や海氷相互作用の理解を深め、海面上昇予測や気候モデル改善に重要な知見を提供する。

<関連情報>

南極半島における上層海洋温暖化による氷河流の10年規模の加速 Decadal glacier flow acceleration caused by upper ocean warming in the Antarctic Peninsula

Yulong Kang, Shichang Kang, Tanuj Shukla, Wanqin Guo, Tao Che, Zongli Jiang
International Journal of Applied Earth Observation and Geoinformation  Available online: 30 March 2026
DOI:https://doi.org/10.1016/j.jag.2026.105268

海洋温暖化が南極氷河流動の加速を引き起こす(Ocean Warming Drives Acceleration of Glacier Flow in Antarctica)

Highlights

  • Widespread acceleration of glacier flow occurred since 2018, with the fastest reaching 4.04 ± 0.50% yr⁻¹ in this period.
  • Identifies 0–300 m upper ocean warming as the dominant driver of sustained glacier acceleration in the Antarctic Peninsula, distinguishing atmospheric and oceanic forcing roles.
  • Provides a quantitative basis for reassessing ice-sheet instability and sea-level rise projections under ongoing climate warming.

Abstract

Mass loss from the Antarctic Ice Sheet has increased sharply in recent decades, driven largely by dynamically imbalanced flow of marine-terminating glaciers. Previous studies have linked short-lived glacier speed-ups to surface meltwater drainage or episodic ocean intrusions, yet it remains unclear whether persistent ocean warming can maintain regional acceleration. Using a decade of Sentinel-1 observations (May 2015–April 2025), we quantify surface velocities for 101 glaciers draining into Beascochea Bay and demonstrate that dynamic imbalance and sustained ice flow acceleration now coexist at regional scale. Mean summer glacier velocities increased by 1.81 ± 0.65%, approximately 0.88% higher than winter month values, and peak summer speeds rose by 6.44 ± 0.74%. Widespread acceleration of glacier flow occurred since 2018, with the fastest reaching 4.04 ± 0.50% yr⁻1 in this period. Further analyses identify upper-ocean warming at 0–300 m depth as the dominant factor, linking sustained acceleration to shallow subsurface heat rather than atmospheric melt. These results reveal a decadal-scale transition from transient to ocean-associated glacier dynamics, in which ocean thermal forcing sustains long-term acceleration even as mechanical stability declines, thereby enhancing the Antarctic Peninsula’s contribution to sea-level rise.

1702地球物理及び地球化学
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