A team led by Stan Jacobs of Columbia University’s Lamont-Doherty Earth Observatory compared data on the glacier gathered in 2009 with previous measurements made in 1994. The scientists found that the ice shelf is currently melting at a rate of about 80 cubic kilometres a year, 50 per cent faster than it was during the early 1990s. The rise in regional ocean temperatures – about 0.2°C – is not enough to account for this increase, the scientists say.

Images sent back by a robot submarine from beneath the ice revealed the presence of an underwater ridge. Some time during the 1970s, the glacier detached from this ridge, allowing warm water rising from the deep ocean to gain access to deeper parts of the glacier, thinning the ice. The reduction of friction between the ice shelf and the sea floor accelerated the glacier’s slide into the sea. 

According to the scientists, an increase in windiness in Antarctica has changed local circulation patterns, causing more warm water from the deep ocean to rise onto the continental shelf, speeding up glacial thinning.

August 2011