Scientists have found two hidden gateways underneath the largest glacier in East Antarctica letting in warm seawater and causing melt.
Research, published in the journal Nature Geoscience today, shows a five kilometre-wide sub-glacial trough which forms a gateway, and another tunnel, extending from beneath the Totten Glacier to the coastline.
There is enough ice in the Totten Glacier to raise global sea levels by 3.5 metres.
The study follows findings from a marine science voyage to the glacier earlier this year which detected glacial melt water.
Jason Roberts, a glaciologist with the Australian Antarctic Division, says the deep trenches were uncovered by airborne geophysical surveys.
“The Totten Glacier is the most rapidly thinning glacier in East Antarctica and this melt has the potential to drive substantial regional ice loss,” Dr Roberts says.
“The study identifies direct pathways for warm ocean water to reach under the glacier; a likely reason for the observed thinning.”
Lead author of the study, Jamin Greenbaum, a PhD student from the University of Texas at Austin, says much of the Totten catchment includes extensive regions where ice is grounded below sea level.
“The glacier catchment reaches as deep as 1.7 kilometers below sea level and is covered by up to four kilometers of ice,” Greenbaum says.
“The large catchment is vulnerable to rapid ice loss if warm ocean currents breach the thin coastal ice.
“While the Totten melt may take many centuries, once change has begun our analysis reveals it would likely be irreversible.”
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