Thursday, July 16, 2015

Antarctic Ice Sheet not as stable in a warmer world

A new study lead by Ph.D. student Melissa Hansen published in Paleoceanography sheds light on the behavior of the East Antarctic Ice Sheet in a warming world. The Antarctic Ice Sheet is the largest in the world and it has some vulnerable areas where the ice lies below sea level. Today, under the current warming climate, Antarctica is gaining mass at the top due to an increase in snow accumulation, but it is melting from below where warmer ocean water melts the ice. In East Antarctica, snow accumulation exceeds the melt from below, but recent studies have suggested that the future may be different. Ms. Hansen and her co-authors show that when ocean temperatures around Antarctica rose to more than 3 degrees C during past warm periods, the ice mass changed from one purging icebergs into the ocean following glacial rhythms to one with a very different dynamic. These results confirm earlier studies that the East Antarctic Ice Sheet might not be as stable under warmer conditions with consequences for predictions of future sea level rise.