A collapse in Antarctic ice sheets could raise sea levels by 2 metres by 2100

The Guardian reports, 30th March 2016: Sea levels could rise far more rapidly than expected in coming decades, according to new research that reveals Antarctica’s vast ice cap is less stable than previously thought.

The UN’s climate science body had predicted up to a metre of sea level rise this century — but it did not anticipate any significant contribution from Antarctica, where increasing snowfall was expected to keep the ice sheet in balance.

According a study, published in the journal Nature, collapsing Antarctic ice sheets are expected to double sea-level rise to two metres by 2100, if carbon emissions are not cut.

Previously, only the passive melting of Antarctic ice by warmer air and seawater was considered but the new work added active processes, such as the disintegration of huge ice cliffs.

“This [doubling] could spell disaster for many low-lying cities,” said Prof Robert DeConto, at the University of Massachusetts Amherst, who led the work. He said that if global warming was not halted, the rate of sea-level rise would change from millimetres per year to centimetres a year. “At that point it becomes about retreat [from cities], not engineering of defences.”

The cities most at risk in richer nations include Miami, Boston and Nagoya, while cities in China, Vietnam, Bangladesh and Ivory Coast are among those most in danger in less wealthy countries.

Prof David Vaughan, at the British Antarctic Survey and not part of the research team, said: “The new model includes for the first time a projection of how in future, the Antarctic ice sheet may to lose ice through processes that today we only see occurring in Greenland.

“I have no doubt that on a century to millennia timescale, warming will make these processes significant in Antarctica and drive a very significant Antarctic contribution to sea level rise. The big question for me is, how soon could this all begin. I’m not sure, but these guys are definitely asking the right questions.”

Source: The Guardian, 30th March 2016. For the full details, see:
www.theguardian.com/environment/2016/mar/30/sea-levels-set-to-rise-far-more-rapidly-than-expected


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