Antarctic loss could double expected sea level rise by 2100, scientists say
Antarctic loss could double expected sea level rise by 2100, scientists say
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.
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DeConto RM, Pollard D. Contribution of Antarctica to past and future sea-level rise. Nature 2016;531(7596):591-7. http://www.nature.com/nature/journal/v531/n7596/full/nature17145.html
Polar temperatures over the last several million years have, at times, been slightly warmer than today, yet global mean sea level has been 6–9 metres higher as recently as the Last Interglacial (130,000 to 115,000 years ago) and possibly higher during the Pliocene epoch (about three million years ago). In both cases the Antarctic ice sheet has been implicated as the primary contributor, hinting at its future vulnerability. Here we use a model coupling ice sheet and climate dynamics—including previously underappreciated processes linking atmospheric warming with hydrofracturing of buttressing ice shelves and structural collapse of marine-terminating ice cliffs—that is calibrated against Pliocene and Last Interglacial sea-level estimates and applied to future greenhouse gas emission scenarios. Antarctica has the potential to contribute more than a metre of sea-level rise by 2100 and more than 15 metres by 2500, if emissions continue unabated. In this case atmospheric warming will soon become the dominant driver of ice loss, but prolonged ocean warming will delay its recovery for thousands of years.
Antarctic loss could double expected sea level rise by 2100, scientists say
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.
…
DeConto RM, Pollard D. Contribution of Antarctica to past and future sea-level rise. Nature 2016;531(7596):591-7. http://www.nature.com/nature/journal/v531/n7596/full/nature17145.html
Polar temperatures over the last several million years have, at times, been slightly warmer than today, yet global mean sea level has been 6–9 metres higher as recently as the Last Interglacial (130,000 to 115,000 years ago) and possibly higher during the Pliocene epoch (about three million years ago). In both cases the Antarctic ice sheet has been implicated as the primary contributor, hinting at its future vulnerability. Here we use a model coupling ice sheet and climate dynamics—including previously underappreciated processes linking atmospheric warming with hydrofracturing of buttressing ice shelves and structural collapse of marine-terminating ice cliffs—that is calibrated against Pliocene and Last Interglacial sea-level estimates and applied to future greenhouse gas emission scenarios. Antarctica has the potential to contribute more than a metre of sea-level rise by 2100 and more than 15 metres by 2500, if emissions continue unabated. In this case atmospheric warming will soon become the dominant driver of ice loss, but prolonged ocean warming will delay its recovery for thousands of years.

