Thursday, August 29, 2013

East Antarctic Ice Sheet could be more vulnerable to climate change than previously thought

Durham University News: The world’s largest ice sheet could be more vulnerable to the effects of climate change than previously thought, according to new research from Durham University. A team from the Department of Geography used declassified spy satellite imagery to create the first long-term record of changes in the terminus of outlet glaciers – where they meet the sea – along 5,400km of the East Antarctic Ice Sheet’s coastline. The imagery covered almost half a century from 1963 to 2012.

Using measurements from 175 glaciers, the researchers were able to show that the glaciers underwent rapid and synchronised periods of advance and retreat which coincided with cooling and warming. The researchers said this suggested that large parts of the ice sheet, which reaches thicknesses of more than 4km, could be more susceptible to changes in air temperatures and sea-ice than was originally believed.

Current scientific opinion suggests that glaciers in East Antarctica are at less risk from climate change than areas such as Greenland or West Antarctica due to its extremely cold temperatures which can fall below minus 30°C at the coast, and much colder further inland.

But the Durham team said there was now an urgent need to understand the vulnerability of the East Antarctic Ice Sheet, which holds the vast majority of the world’s ice and enough to raise global sea levels by over 50m. The findings are published in the prestigious scientific journal Nature.

Dr Chris Stokes, in Durham’s Department of Geography, said: “We know that these large glaciers undergo cycles of advance and retreat that are triggered by large icebergs breaking off at the terminus, but this can happen independently from climate change. “It was a big surprise therefore to see rapid and synchronous changes in advance and retreat, but it made perfect sense when we looked at the climate and sea-ice data....

A 1913 shot of Adelie Land, from the National Library of Australia

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