Tuesday, January 24, 2017

Giant iceberg set to calve from Larsen C Ice Shelf

n ice shelf is a floating extension of land-based glaciers which flow into the ocean. Because they already float in the ocean, their melting does not directly contribute to sea-level rise. However, ice shelves act as buttresses holding back glaciers flowing down to the coast. Larsen A and B ice shelves, which were situated further north on the Antarctic Peninsula, collapsed in 1995 and 2002, respectively. This resulted in the dramatic acceleration of glaciers behind them, with larger volumes of ice entering the ocean and contributing to sea-level rise.
The largest icebergs known have all calved from ice shelves. In 1956, a huge iceberg of roughly 32,000 km² – bigger than Belgium – was spotted in the Ross Sea by a US Navy icebreaker. However, since there were no satellites in orbit at this point, its exact size was not verified. In 1986, a section of the Filchner ice shelf roughly the size of Wales calved – but this iceberg broke into three pieces almost immediately. The largest iceberg recorded by satellites calved from the Ross ice shelf in 2001, and was roughly the size of Jamaica at 11,000 km².
The below video shows footage from the breakup of the Wilkins ice shelf, also on the Antarctic Peninsula, in 2008.