One of Greenland鈥檚 largest glaciers is crashing into the sea dramatically faster than before, reigniting fears about the stability of the island鈥檚 ice sheet in the face of local warming.
Gordon Hamilton, a glaciologist at the University of Maine in Orono, measured the flow of the Kangerdlugssuaq glacier in eastern Greenland from on board the Greenpeace ship Arctic Sunrise last week. He says that it is flowing into the sea at 1.6 metres an hour, three times as fast as when it was last measured in 1988, and almost as fast as the world鈥檚 speediest glacier, west Greenland鈥檚 Jakobshavn Isbrae.
Glaciologists are worried by the change in Kangerdlugssuaq because, as reported four years ago, the glacier is also becoming thinner. Many Greenland glaciers surge periodically, says David Vaughan of the British Antarctic Survey in Cambridge, UK, but faster flow combined with thinning is unusual. It suggests that the glacier is speeding up because melting ice is lubricating the rock beneath, and reducing friction where they meet. 鈥淚f this is occurring on neighbouring glaciers, the case for a climate influence would be strong,鈥� says Vaughan.
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The Greenland ice sheet holds enough ice to raise sea levels by 7 metres, and these two speedy glaciers between them drain 10 per cent of Greenland鈥檚 ice. Unless the melting ice is replaced with greater snowfall inland, which appears unlikely, it will raise sea levels worldwide.
