Research press release


Nature Geoscience

Geoscience: Partial Eurasian ice sheet collapse may have led to rapid sea level rise

ユーラシア氷床の一部が約1万4650年前に崩壊し、400年未満の間に、全球海水準の12から14メートルの上昇に大きく寄与したすることを示した論文が、Nature Geoscience に掲載される。


今回、Jo Brendryenたちは、ノルウェー海で得られた堆積物コアの年代データに基づいてこれらの事象の時期を分析した。詳細に年代を再現した結果から、ユーラシア氷床の一部(現在の西南極氷床の大きさに匹敵)が融解したのは、融水パルス1A事象と同時期であり、氷床の崩壊は500年以内の期間に急速に発生したことが示された。著者たちは、ユーラシア氷床のこの後期の融解が、12〜14メートルの急速な全球海水面上昇の20〜60%に寄与した可能性を示唆している。


Portions of the Eurasian Ice Sheet collapsed around 14,650 years ago, and substantially contributed to a 12- to 14-metre global sea-level rise in fewer than 400 years, according to a paper published in Nature Geoscience.

The Last Glacial Maximum was a period in Earth’s history that began around 33,000 years ago and was characterized by low global temperatures and vast ice sheets that covered much of the Northern Hemisphere. During this period the Eurasian Ice Sheet’s maximum ice volume was approximately three times greater than that of the modern-day Greenland Ice Sheet. It was the third-largest ice sheet at that time. However, much of the Eurasian Ice Sheet was thought to have melted too early to contribute to the rapid sea-level rise some 14,600 years ago, known as the Meltwater Pulse 1A event, that coincided with a period of abrupt climate warming.

Jo Brendryen and colleagues analysed the timing of these events based on age data of sediment cores from the Norwegian Sea. The detailed age reconstruction showed that the melting of part of the Eurasian Ice Sheet — which is comparable in size to the modern West Antarctic Ice Sheet — was coincident with the Meltwater Pulse 1A event, and that the ice-sheet collapse was fast, occurring over a period of less than 500 years. The authors suggest that this later melting of the Eurasian Ice Sheet may have contributed 20–60% of the rapid 12- to 14-metre global sea-level rise.

These findings may provide a better understanding of the vulnerability of modern ice sheets to such rapid collapse today.

doi: 10.1038/s41561-020-0567-4


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