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Sunday, May 17, 2009

17 Million Bangladeshis to be displaced: Sea level rise due to meltdown of West Antarctic ice

17 Million Bangladeshis to be displaced: Sea level rise due to meltdown of West Antarctic ice

Staff Reporter, The New Nation, Bangladesh, May x, 2009

More than 17 million people in Bangladesh would be displaced by a sea level rise of 1.5 metres, warned Jonathan Bamber, a professor at Bristol University in England, disclosing a study report which found that a collapse of the ice sheet of West Antarctica would push up world sea levels by 3.3 metres (11 ft.) over hundreds of years.

"The consequences for the planet and stability of society as a whole for even a 1-2 metres rise is very, very serious," he said in Friday's edition in the journal Science.

Bamber set aside a previous projection that a meltdown of West Antarctica's ice sheet would raise sea levels by 5-6 metres and said the rise can be 3.3 metres but the impact would still be catastrophic, especially for U.S. coastal cities.

Sea levels of North America would rise more than anywhere else under the new projections, Bamber and experts at University of Durham in England and Delft University of Technology in the Netherlands, said.

"Antarctica's vast mass exerts a gravitational tug that raises water levels in the Southern Ocean. If that ice were to melt, computer models project that sea levels would rise fastest around North America, while falling in the Southern Ocean."

"Levels on the U.S. seaboards would rise 25% more than the global average and threaten cities like New York, Washington DC, and San Francisco," the University of Colorado at Boulder, where Bamber is now a visiting fellow, said in a statement.

The study found that West Antarctica is also vulnerable because much of its ice rests on bedrock below sea level. Global warming, blamed by the United Nations Panel on Climate Change on human use of fossil fuels, could let water seep in under the ice and make giant chunks buoyant.

Any such collapse would probably last hundreds of years, leaving West Antarctica as a series of islands, Bamber said, adding there was evidence that West Antarctica had collapsed in the past, perhaps as recently as 400,000 years ago.

The vast East Antarctic sheet, equivalent to about 50 metres of sea level rise, and Greenland, equivalent to 7 metres, rest on bedrock above sea level.

About 10 ice shelves further north on the Antarctic Peninsula have broken up in recent years, most recently part of the Wilkins Ice Shelf shattered into icebergs last month.

The U.N. Climate Panel projected in a 2007 report that world sea levels would rise by between 18 and 59 cm (7-24 inches) this century because of global warming -- excluding any accelerating thaw of Antarctica or Greenland.

Bamber's study, which updated data from a 1978 report that estimated a 5-6-metre rise, looked solely at the risks of collapse of West Antarctica. The pattern of sea level rise would be different -- especially in the Atlantic -- if Greenland shrank simultaneously.

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