ABSTRACT

Over 40 years ago, the glaciologist John Mercer warned that parts of the West Antarctic Ice Sheet were at risk of collapse due to the CO2 greenhouse effect. Mercer recognised the unique vulnerability of ice sheets resting on beds far below sea level (marine-based ice sheets), where an initial warming signal can initiate irreversible retreat. In this paper, we review recent work on evidence for ice sheet collapse in warmer periods of the recent geological past, the current behaviour of the ice sheet, and computer models used to predict future ice-sheet response to global warming. Much of this work points in the same direction: warming climates can indeed trigger collapse of marine-based portions of the West Antarctic Ice Sheet, and retreat in response to recent warming has brought parts of the ice sheet to the threshold of instability. Further retreat appears to be inevitable, but the rate of collapse depends critically on future emissions.

摘要

40多年前，冰川学家约翰·默瑟（John Mercer）警告说，由于二氧化碳温室效应，西部南极冰原的部分地区有倒塌的危险。美世公司认识到，放在远低于海平面的床上的冰盖（基于海洋的冰盖）存在独特的脆弱性，在那里初始的变暖信号会引发不可逆的撤退。在本文中，我们回顾了有关最近地质过去的较暖时期冰盖坍塌证据，冰盖当前行为以及用于预测未来冰盖对全球变暖反应的计算机模型的最新工作。大部分工作都指向同一方向：变暖的气候确实会引发南极西部冰原海基部分的崩塌，而由于近期变暖而退缩使部分冰原达到了不稳定的极限。