Antarctic Waters Replicating Prehistoric Sea Level Rise

摘要

Current changes in the ocean around Antarctica are disturbingly close to conditions 14,000 years ago that contributed to the rapid melting of Antarctic ice and an abrupt global sea level rise of 3-4 metres. New research published in Nature Communications has found that in the past, when ocean temperatures around Antarctica became more layered - with a warm layer of water below a cold surface layer - ice sheets and glaciers melted much faster than when the cool and warm layers mixed more easily. This defined layering of temperatures is exactly what is happening now around the Antarctic. "The reason for the layering is that global warming in parts of Antarctica is causing land-based ice to melt, adding massive amounts of freshwater to the ocean surface," said co-author Prof Matthew England of the ARC Centre of Excellence for Climate System Science. "At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers on Pine Island and Totten. It appears global warming is replicating conditions that, in the past, triggered significant shifts in the stability of the Antarctic ice sheet."