UNIVERSITY PARK, Pa. -- An ice sheet model that includes previously underappreciated processes indicates that sea level may rise almost 50 feet by 2500 due to Antarctic ice sheet melting if greenhouse gas emissions continue unabated, according to researchers from Penn State and University of Massachusetts, Amherst.
"In this case the atmospheric warming will soon become the dominant driver of ice loss, but prolonged ocean warming will delay the recovery for thousands of years," the researchers report in the Mar. 31 issue of Nature.
Antarctica was the primary contributor to sea level rise in the past and may be the primary contributor in the future because much of its ice sits on ground. Floating ice, like that of the Arctic Ocean, is already in the water and if it melts, does not raise sea level. The Antarctic contribution will also probably dominate melt from the smaller Greenland Ice Sheet. While only parts of Antarctica will melt in the worst case scenario, the melting suggested by the model would be sufficient to double the recent estimates by the Intergovernmental Panel on Climate Change for future sea-level rise over the next 100 years.
"Recently we looked at the long-standing problem posed by geological evidence that suggests sea level rose dramatically in the past, possibly up to 10 to 20 meters around 3 million years ago in the Pliocene," said David Pollard, senior scientist in Earth and Environmental Systems Institute, Penn State. "Existing models couldn't simulate enough ice sheet melting to explain that."