氷河の融解が加速し、淡水源は減少、海面上昇は加速する(As glaciers melt faster, freshwater sources dwindle and sea-level rise accelerates)

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2025-02-19 アリゾナ大学

アリゾナ大学の研究者を含む国際研究チームは、世界中の氷河が急速に融解し、地域の淡水資源の減少と地球規模の海面上昇を加速させていることを明らかにしました。この研究によれば、氷河は過去20年間で年間平均2730億トンの氷を失い、融解速度は36%増加しています。特に、2000年から2023年の間に氷河は合計7211億トンの氷を失い、全球の海面上昇に約1.9センチ寄与しました。この氷河の質量損失は、グリーンランドや南極の氷床によるものを上回り、海面上昇の主要因の一つとなっています。さらに、氷河の融解は中央アジアや中央アンデスなどの地域で重要な淡水資源の喪失を意味し、これらの地域社会に深刻な影響を及ぼす可能性があります。

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2000年から2023年までの世界の氷河量の変化をコミュニティが予測 Community estimate of global glacier mass changes from 2000 to 2023

The GlaMBIE Team
Nature  Published:19 February 2025
DOI:https://doi.org/10.1038/s41586-024-08545-z

氷河の融解が加速し、淡水源は減少、海面上昇は加速する(As glaciers melt faster, freshwater sources dwindle and sea-level rise accelerates)

Abstract

Glaciers are indicators of ongoing anthropogenic climate change1. Their melting leads to increased local geohazards2, and impacts marine3 and terrestrial4,5 ecosystems, regional freshwater resources6, and both global water and energy cycles7,8. Together with the Greenland and Antarctic ice sheets, glaciers are essential drivers of present9,10 and future11,12,13 sea-level rise. Previous assessments of global glacier mass changes have been hampered by spatial and temporal limitations and the heterogeneity of existing data series14,15,16. Here we show in an intercomparison exercise that glaciers worldwide lost 273 ± 16 gigatonnes in mass annually from 2000 to 2023, with an increase of 36 ± 10% from the first (2000–2011) to the second (2012–2023) half of the period. Since 2000, glaciers have lost between 2% and 39% of their ice regionally and about 5% globally. Glacier mass loss is about 18% larger than the loss from the Greenland Ice Sheet and more than twice that from the Antarctic Ice Sheet17. Our results arise from a scientific community effort to collect, homogenize, combine and analyse glacier mass changes from in situ and remote-sensing observations. Although our estimates are in agreement with findings from previous assessments14,15,16 at a global scale, we found some large regional deviations owing to systematic differences among observation methods. Our results provide a refined baseline for better understanding observational differences and for calibrating model ensembles12,16,18, which will help to narrow projection uncertainty for the twenty-first century11,12,18.

1702地球物理及び地球化学
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