重新审视海洋冰崖不稳定引起的南极冰损失
文章标题：Revisiting Antarctic ice loss due to marine ice-cliff instability
文章作者：Tamsin L. Edwards, Mark A. Brandon, Gael Durand, Neil R.Edwards, Nicholas R. Golledge, Philip B. Holden, Isabel J. Nias, Antony J.Payne, Catherine Ritz & Andreas Wernecke
DOI:
https://doi.org/10.1038/s41586-019-0901-4
原文链接：
https://www.nature.com/articles/s41586-019-0901-4
内容提要：由于来自南极洲的融化，科学家对本世纪海平面上升的预测范围从零到一米多。最高的预测是由有争议的海洋冰崖不稳定性（MICI）假设得出，该假设认为，由于全球变暖引起的地表和次冰架融化，沿海冰崖在冰架崩解后会迅速坍塌。但是现在人们尚未观察到MICI，并且尚不清楚是否需要再现过去地质时期的海平面变化。本文量化了原始MICI研究的冰盖建模不确定性，并显示概率分布倾向于较低的值（在非常高的温室气体浓度下，最可能的值是45厘米）。然而在上新世中期、末次间冰期或1992~2017年间，MICI并不需要因南极冰盖损失而重现海平面变化；研究发现排除MICI的预测结果与先前的研究一致（95%的概率小于43厘米）。该研究得出结论，以前对这些MICI预测的解释高估了本世纪海平面的上升趋势；因为MICI假设没有得到很好的约束，对MICI进行预测的需要更大范围的观测约束，以模拟冰架脆弱性和冰崖崩塌。
论文摘要：Predictions for sea-level rise this century due to melt from Antarctica range from zero to more than one metre. The highest predictions are driven by the controversial marine ice-cliff instability (MICI) hypothesis, which assumes that coastal ice cliffs can rapidly collapse after ice shelves disintegrate, as a result of surface and sub-shelf melting caused by global warming. But MICI has not been observed in the modern era and it remains unclear whether it is required to reproduce sea-level variations in the geological past. Here we quantify ice-sheet modelling uncertainties for the original MICI study and show that the probability distributions are skewed towards lower values (under very high greenhouse gas concentrations, the most likely value is 45 centimetres). However, MICI is not required to reproduce sea-level changes due to Antarctic ice loss in the mid-Pliocene epoch, the last interglacial period or 1992–2017; without it we find that the projections agree with previous studies (all 95th percentiles are less than 43 centimetres). We conclude that previous interpretations of these MICI projections over-estimate sea-level rise this century; because the MICI hypothesis is not well constrained, confidence in projections with MICI would require a greater range of observationally constrained models of ice-shelf vulnerability and ice-cliff collapse.
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