Icecap Melting At Half Of IPCC Estimated Rate

From "New study slashes estimate of icecap loss" AFP - Wednesday, September 8:

Estimates of the rate of ice loss from Greenland and West Antarctica, one of the most worrying questions in the global warming debate, should be halved, according to Dutch and US scientists.

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When the glaciers started to retreat around 20,000 years ago, the crust started to rebound, and is still doing so.

This movement, though, is not just a single vertical motion, lead researcher Bert Vermeersen of Delft Technical University, in the Netherlands, said in phone interview with AFP.

"A good analogy is that it's like a mattress after someone has been sleeping on it all night," he said.

The weight of the sleeper creates a hollow as the material compress downwards and outwards. When the person gets up, the mattress starts to recover. This movement, seen in close-up, is both upwards and downwards and also sideways, too, as the decompressed material expands outwards and pulls on adjacent stuffing.

Often ignored or considered a minor factor in previous research, post-glacial rebound turns out to be important, says the paper.

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"The corrections for deformations of the Earth's crust have a considerable effect on the amount of ice that is estimated to be melting each year," said Vermeersen, whose team worked with NASA's Jet Propulsation Laboratory and the Netherlands Institute for Space Research.

"We have concluded that the Greenland and West Antarctica ice caps are melting at approximately half the speed originally predicted."

Read the complete article here.