The front of a 鈥渄oomsday glacier鈥� in Antarctica is expected to see 鈥渄ramatic changes鈥� within 10 years that will accelerate its break-up and contribution to sea level rise, according to findings presented at a meeting of the American Geophysical Union on 13 December.
Thwaites glacier is about the size of Great Britain and sheds 50 billion tonnes of ice per year. While that is small in terms of contributing to sea level rise, the tongue of ice is closely watched by researchers because of the buttressing effect it has in holding back the entire West Antarctic ice sheet, which has the potential to raise seas by more than 3 metres.
That disastrous outcome isn鈥檛 guaranteed and may not unfold for centuries. But major changes to the ice sheet could come much sooner. at Oregon State University said at a press conference that Thwaites glacier will imminently lose its grip on a 15 kilometre-long 鈥減inning point鈥�, where its floating front is held in place by a seamount under the water.聽
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鈥淚t鈥檚 [already seen] a very significant decrease in contact area [between the glacier and seamount],鈥� she said. 鈥淲e are predicting if it continues on its current trend, using current processes ongoing, we expect it will reduce down to near zero contact within a decade.鈥澛�
鈥淭here鈥檚 going to be a dramatic change in the front of the glacier, probably in less than a decade,鈥� said at the University of Colorado Boulder, speaking at the same event. 鈥淲hen that happens, the fast flow-apart of Thwaites is likely to widen because the bracing on the east side will be gone. It will widen the dangerous part of the glacier.鈥�
Thwaites is being undermined from underneath by warm water linked to climate change. The glacier has gradually been losing its grip on the stabilising seamount since 2004 and, , that connection will 鈥渂e gone by 2030鈥�.
Still, Pettit cautions that the process is unlikely to be linear. 鈥淚t could increase more rapidly or slow down and stick around, and we might have another mode of failure,鈥� she said.
One of the other ways Thwaites鈥檚 collapse could speed up is through fracturing, as large cracks propagate across its surface. Pettit said she expects that to happen in less than five years鈥� time, sooner than the loss of grip with the seamount.
Scambos said he hopes that a growing number of field observations of Thwaites, from above and below using everything from remote-operated vehicles to seals outfitted with temperature and salinity monitors, will help narrow the wide range of projections of future sea level rise from the region.聽
搁别蹿别谤别苍肠别:听The Cryosphere,聽DOI:
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