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Scientists have discovered deep seabed channels beneath the Thwaites Glacier that could help them understand how the massive sheet of ice known as the “Doomsday Glacier” will contribute to future global sea level rises.
Researchers from the UK and US International Thwaites Glacier Collaboration (ITGC) gathered data from ice shelves in West Antarctica from January to March last year.
At 192,000 square kilometres, the Thwaites Glacier is the size of Great Britain or the US state of Florida. But according to the scientists, the large mass is particularly vulnerable to climate and ocean changes.
The study, which was published in the journal The Cryosphere, revealed that ice draining from Thwaites into the Amundsen Sea already accounts for about four percent of global sea-level rise.
A runaway collapse of the glacier could lead to a significant increase in sea levels of around 65 cm (25 inches), said the researchers.
“For the first time we have a clear view of the pathways along which warm water can reach the underside of the glacier, causing it to melt and contribute to global sea-level rise,” said lead author, and marine geophysicist at the British Antarctic Survey (BAS), Dr Kelly Hogan.
“We found the coastal sea floor, which is incredibly rugged, is a really good analogue for the bed beneath the present-day Thwaites Glacier both in terms of its shape and rock type.
“By examining retreat patterns over this sea-floor terrain we will be able to help numerical modellers and glaciologists in their quest to predict future retreat.
“This research has filled a critical data gap. Together the new coastal sea floor maps and the cavity maps track the deep channels for over 100 km to where the glacier sits on the bed. ”
While one team collected airborne data flying over the glacier and ice shelf in a BAS Twin Otter aircraft, the other mapped the sea floor at the ice front from the US Antarctic Program icebreaker RV Nathaniel B Palmer.
Dave Porter at LDEO Columbia University, said: “Flying over the recently-collapsed ice tongue and being able to see first-hand the changes occurring at Thwaites Glacier was both awe inspiring and disconcerting, but also gratifying to know the airborne data we were collecting would help reveal the hidden structures below.”
The team of scientists concluded that the sea floor is deeper and it has more deep channels leading towards the grounding line under the ice shelf than was previously thought.
Lead author Dr Tom Jordan, an aero-geophysicist at BAS, who led the airborne survey, added: “It was fantastic to be able to map the channels and cavity system hidden beneath the ice shelf; they are deeper than expected – some are more than 800 metres deep. They form the critical link between the ocean and the glacier.
“The offshore channels, along with the adjacent cavity system, are very likely to be the route by which warm ocean water passes underneath the ice shelf up to the grounding line, where the ice meets the bed.”
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Glacier, Thwaites Glacier, Antarctica, British Antarctic Survey
World news – GB – Map of channels ‘links Thwaites Glacier to future sea level rise’