Global warming suspected in rapid thinning of antarctic ice

Global warming is thought to be behind the rapid thinning of a previously stable ice sheet on the Southern Antarctic Peninsula.

The sudden increase in ice melt from multiple glaciers along some 750 kilometres of coastline since 2009 was detected by European scientists using satellite data.

“To date, the glaciers have added roughly 300 cubic kilometres of water to the ocean.

That’s the equivalent of the volume of nearly 350,000 Empire State Buildings combined,” said Bert Wouters from the University of Bristol in Britain, who led the study, published in the Washington-based journal Science.

Sea levels worldwide have risen as a result, German Press Agency dpa reported.

The scientists see the likely cause of the ice loss to be warming ocean currents in the region due to climate change.

“The warming first melts the underside of the (floating) shelf ice, which up to now has stabilized the inland ice,” explained Veit Helm, a geophysicist from the Bremerhaven-based Alfred Wegener Institute (AWI) for Polar and Marine Research who took part in the study.
This, he said, reduces the buttressing effect of the shelf ice on the glaciers’ slow flow into the ocean, causing the inland ice to thin out with increasing speed.

“The system has become unstable,” Helm remarked. Ice cover on the Southern Antarctic Peninsula had previously been considered stable compared with other regions on the continent.

According to the scientists, the thickness of some of the glaciers is now decreasing by as much as four metres a year.

The ice loss is so large that a pair of NASA satellites have detected small changes in the Earth’s gravitational field.

“The fact that so many glaciers in such a large region suddenly started to lose ice came as a surprise to us,” Wouters said.