The Amundsen Sea sector of the West Antarctic Ice Sheet has most likely been destabilized and ice retreat is unstoppable for the current conditions. No further acceleration in climate change is necessary to trigger the collapse of the rest of the West Antarctic Ice Sheet on decadal time scales. Antarctica has the potential to contribute more than a metre of sea-level rise by 2100. A large fraction of West Antarctic basin ice could be gone within two centuries, causing a 3–5 metre sea level rise. Mechanisms similar to those causing deglaciation in West Antarctica are now also found in East Antarctica. Partial deglaciation of the East Antarctic ice sheet is likely for the current level of atmospheric carbon dioxide, contributing to 10 metres of more of sea level rise in the longer run, and 5 metres in the first 200 years. INTRODUCTION The West Antarctic Ice Sheet (WAIS), […]