Accelerating ice loss from the Antarctic icesheet could be due in part to active volcanoes under the frozen continent’s eastern part, a study said on Sunday. From 2002 to 2011, the average annual rate of Antarctic icesheet loss increased from about 30 billion tonnes to about 147 billion tonnes, the UN’s panel of climate scientists reported in September. The icesheet is a mass of glacial land ice — one such sheet covers most of Greenland and the other Antarctica, and together they contain most of the freshwater on Earth. The sheets are constantly moving, slowly flowing downhill and seawards under their own weight.