By Sid Perkins
From San Francisco, at a meeting of the American Geophysical Union
In today’s warming climate, the significant melting of the ice sheets capping Greenland and Antarctica garners a lot of attention. However, the ongoing melting of glaciers and other small ice masses worldwide actually makes a larger contribution to the rise in sea level, a new study suggests.
Sea level is now rising about 3 millimeters each year, says W. Tad Pfeffer, a glaciologist at the University of Colorado at Boulder. While some of that increase comes from the expansion of ocean water as it gets warmer, most of the boost is caused by meltwater from land-based ice. The melting of icebergs and of the floating ice shelves that fringe Antarctica doesn’t raise sea level.