The Straits Times

Estimated icecap loss halved
The Straits Times

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.

In the last two years, several teams have estimated Greenland is shedding roughly 230 gigatonnes of ice, or 230 billion tonnes, per year and West Antarctica around 132 gigatonnes annually.

But, according to the new study, published in the Sept issue of the journal Nature Geoscience, the ice estimates fail to correct for a phenomenon known as glacial isostatic adjustment.

This is the term for the rebounding of Earth’s crust following the last Ice Age. Glaciers that were kilometers thick smothered Antarctica and most of the northern hemisphere for tens of thousands of years, compressing the elastic crust beneath it with their titanic weight.

With glacial isostatic adjustment modelled in, the loss from Greenland is put at 104 gigatonnes, plus or minus 23 gigatonnes, and 64 gigatonnes from West Antarctica, plus or minus 32 gigatonnes. ‘We have concluded that the Greenland and West Antarctica ice caps are melting at approximately half the speed originally predicted,’ said Mr Vermeersen.