Scientists nearly double sea level rise projections for 2100, because of Antarctica

By:  Brady Dennis and Chris Mooney

Sea levels could rise nearly twice as much as previously predicted by the end of this century if carbon dioxide emissions continue unabated, an outcome that could devastate coastal communities around the globe, according to new research published Wednesday. 

The startling findings, published in the journal Nature, paint a far grimmer picture than current consensus predictions, which have suggested that seas could rise by just under a meter at most by the year 2100. Those estimates relied on the notion that expanding ocean waters and the melting of relatively small glaciers would fuel the majority of sea level rise, rather than the massive ice sheets of Greenland and Antarctica.

The scientists behind Wednesday’s study used sophisticated computer models to decipher a longstanding riddle about Antarctica: how did it surrender so much ice during previous warm periods? They found that similar conditions in the future could lead to monumental and irreversible increases in sea levels. If high levels of greenhouse gas emissions continue, they concluded, oceans could rise by close to two meters in total (more than six feet) by the end of the century. The melting of ice on Antarctica alone could cause seas to rise more than 15 meters (49 feet) by 2500.

The projection “nearly doubles” prior estimates of sea level rise, which had relied on a “minimal contribution from Antarctica,” said Rob DeConto of University of Massachusetts, Amherst, who authored the study with  David Pollard of Penn State University.

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