Study Halves Projected Sea Rise if Antarctic Ice Sheets Melt

The disintegration of Antarctica’s vast western ice sheets would cause seas to rise only half as much as previously estimated, according to a new report. While previous studies projected that a partial or total collapse of Antarctica’s massive western sheets would raise seas by about 20 feet, a new report published in the journal Science suggests that sea levels would rise by only about 11 feet. The study combined computer modeling with measurements of the ice and the underlying bedrock. “Our calculations show those [earlier] estimates are much too large, even on a thousand-year timescale,” said the study’s lead author, Jonathan Bamber, of the University of Bristol. Scientists consider West Antarctica vulnerable to collapse because so much of the ice sits on bedrock well below sea level. But while the new report is less dire than earlier projections, the authors called for renewed investment in satellite monitoring to clarify the global risk. They predict seas will rise 25 percent more on both U.S. coasts because shifting such a mass of ice would alter gravity locally and cause water to build up in the northern oceans.