The contribution of Antarctica to sea-level rise is highly uncertain. One important source of uncertainty is a lack of consensus on which mechanisms act during the demise of Antarctic ice masses. A particularly debated mechanism is that of marine ice cliff instability (MICI), where the formation of tall ice cliffs could lead to a rapid collapse of ice sheets.

In their study, Mathieu Morlighem from Dartmouth College and colleagues from the USA and the UK used a new parametrization of MICI in three ice-sheet models to assess the risks of MICI after a hypothetical loss of the ice shelves in the Amundsen Sea Embayment. They find that the ice cliffs do not collapse even if the currently stabilizing ice shelves in front of them are removed. Similarly, a collapse is not seen in simulations in which the authors impose a grounding-line retreat and then expose substantially higher ice cliffs, as the enhanced ice discharge is stabilized by an increase in ice flow and ice thinning. These findings indicate that while West Antarctica is still at high risk of rapid melt under global warming, it might not be vulnerable to MICI in the near future.

南极洲对海平面上升的贡献高度不确定。不确定性的一个重要来源是对于南极冰块消亡期间哪些机制起作用缺乏共识。一个特别有争议的机制是海洋冰崖不稳定（MICI），其中高冰崖的形成可能导致冰盖迅速崩塌。

在他们的研究中，达特茅斯学院的 Mathieu Morlighem 以及来自美国和英国的同事在三个冰盖模型中使用了 MICI 的新参数化，以评估假设阿蒙森海湾冰架消失后 MICI 的风险。他们发现，即使当前稳定的冰架被移除，冰崖也不会崩塌。类似地，在作者实施接地线撤退然后暴露出更高的冰崖的模拟中也没有看到崩塌，因为冰流量的增加和冰变薄可以稳定增强的冰排放。这些发现表明，虽然西南极洲在全球变暖的情况下仍然面临快速融化的高风险，但在不久的将来可能不会受到 MICI 的影响。