A 2.7-square-mile (7-square-kilometer) section has broken off Greenland's Jakobshavn Isbrae glacier, NASA scientists report. Greenland's ice sheet, which is 2 miles (3.2 km) thick and covers an area about the size of Mexico, has been losing ice mass at an accelerating rate over the last decade. The ice sheet discharges much of its ice through fast moving glaciers that flow into the sea, with large chunks breaking off into the ocean. This most recent breakup last week pushed the calving front – where the ice sheet meets the ocean – back nearly a mile (1.5 km) in one day. The front is now farther inland than at any time previously observed.
The U.S. National Snow and Ice Data Centre, the Colorado-based institute that tracks the annual cycle of winter ice buildup and summer thaw, says in its latest report that June's rapid melt - which followed a similar record-setting retreat in May - means the polar ice cover remained on pace to shrink more than it did in 2007, when an unprecedented loss of ice first prompted scientists to raise alarms about the Arctic as a harbinger of global climate change.
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