Azara Blog: Greenland ice sheet melting faster than previously thought

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Date published: 2006/02/17

The BBC says:

Greenland's glaciers are sliding towards the sea much faster than previously believed, scientists have told a conference in St Louis, US.

It was thought the entire Greenland ice sheet could melt in about 1,000 years, but the latest evidence suggests that could happen much sooner.

It implies that sea levels will rise a great deal faster as well.

Details of the study, by Nasa and University of Kansas researchers, are also reported in the journal Science.

The comprehensive analysis found that the amount of ice dumped into the Atlantic Ocean has doubled in the last five years.

If the Greenland ice sheet melted completely, it would raise global sea levels by about 7m.

Greenland's contribution to global sea level rise today is two to three times greater than it was in 1996.

"We are concerned because we know that sea levels have been able to rise much faster in the past - 10 times faster. This is a big gorilla. If sea level rise is multiplied by 10 or more, I'm not sure we can deal with that," co-author Eric Rignot, from the US space agency's (Nasa) Jet Propulsion Laboratory in California, told the BBC News website.

Previous estimates suggested it would take many hundreds of years for the Greenland ice sheet to melt completely. The new data will cut this timescale, but by how much is uncertain.

"It depends on how fast the glaciers can go and how sustainable the acceleration can be," said Dr Rignot.

He added: "It takes a long time to build and melt an ice sheet, but glaciers can react quickly to temperature changes."

In 1996, Greenland was losing about 100 cubic km per year in mass from its ice sheet. In 2005, this had increased to about 220 cubic km. By comparison, the city of Los Angeles uses about one cubic km of water per year.

Well we are getting such stories almost every week these days, so nobody should be really surprised by any of this. The only question, as usual, is what should be done in the near term. The global economy is not going to stop tomorrow even if it was guaranteed the sea level were to rise by 7m in a few centuries. You can be sure that most people who attended the conference where these results were discussed came by airplane. So the scientists are not so worried as to change their own behaviour yet.

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