PLEA Network

15 February 2016, Climate News Network, Warmer seas speed up Antarctic ice melt. New scientific studies provide a further warning of the increasing vulnerability of Antarctic glaciers to faster melting as temperatures rise in the Southern Ocean. European researchers have once again warned that the thinning of the Antarctic ice shelf means that the flow of glaciers on the frozen continent could accelerate, with a consequent rise in sea levels. They examine, in two separate studies, the increasingly precarious state of some of the ice shelf. When the shelf, consisting of ice floating on the ocean, melts, it makes no difference to sea levels. But the floating ice does have an effect on the land. It serves as a brake on the pace of glaciers on their journey down to the sea – and the combined impact of warmer atmospheres and warmer seas in the Southern Ocean are rapidly thinning much of the ice shelf. Johannes Fürst, a researcher at the University of Erlangen-Nuremberg’s Institute of Geography in Germany, and colleagues report in Nature Climate Change that they analysed years of ice thickness data from European Space Agency satellites and airborne measurements. Land-borne ice They calculated that only 13% of the total ice shelf area of Antarctica could be called “passive” ice − that is, it plays no role in buttressing or slowing the land-borne ice. But in the last 20 years, observers have measured the successive losses to large areas of the Larsen ice shelf off the Antarctic Peninsula, and these have resulted in an alarming acceleration of glacial flow on land, even though Antarctica remains the coldest continent on Earth. In some cases, the speed of flow has increased eightfold. “If the ocean temperature rises by more than 2°C compared with today, the marine-based West Antarctic ice sheet will be irreversibly lost”. Dr Fürst says: “In contrast to the situation in Greenland, the loss of inland ice in West Antarctica is not caused by melting. It is much too cold for that to happen. The decrease is due to the glaciers flowing into the sea at a faster rate than 20 years ago − what we call dynamic ice loss. Read More here