A kayak trip through a glacier 1:54
(CNN) -
Deep channels discovered under Antarctica's so-called "Doomsday Glacier" may be allowing warm ocean water to melt the bottom of the ice, according to scientists collecting data from an area crucial to understanding the rise in ice. sea level.
Findings published in the journal
The Cryosphere
show that the ocean floor is deeper than previously thought, with deeper channels leading to the
shoreline
where the ice meets the bed.
The ice that drains from the gigantic Thwaites Glacier into the Amundsen Sea in West Antarctica already accounts for about 4% of global sea level rise, and scientists say it is highly susceptible to climate change.
View from the Nathaniel B. Palmer icebreaker en route to the Thwaites Glacier.
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Over the past three decades, the rate of ice loss from Thwaites, which is roughly the size of Great Britain or the state of Florida, and its neighboring glaciers has multiplied by more than five times.
If Thwaites were to collapse it could cause a rise in sea level of around 64 centimeters, and researchers are trying to find out how soon this is likely to happen.
Scientists from the International Thwaites Glacier Collaboration (ITGC) collected data by flying over the glacier in a British Antarctic Survey (BAS) Twin Otter aircraft and mapping the seafloor from the RV Nathaniel B. Palmer icebreaker of the US Antarctic Program.
Drone photo.
The hidden cavities under the ice shelf are likely the route through which warm ocean water passes under the ice shelf to the grounding line, they said.
"The Thwaites Glacier itself is probably one of the most important glaciers in West Antarctica, because it's so big, because we can see that it's changing today," Dr. Tom Jordan, a BAS aerogeophysicist who led the research, told CNN. aerial.
“And also, we know that its bed goes down, and it gets deeper and deeper under the ice sheet, which means that, theoretically, a process called sea ice sheet instability can occur.
And once it starts to retreat, it keeps going backwards.
Cliffs of the Thwaites Glacier, which accounts for 4% of global sea level rise.
"A big step"
Jordan said the next phase was to incorporate the data from the channels, some of them 800 meters deep, into simulations of how the ice sheet will respond in the future.
Until now, he said, the ITGC had not been able to accurately quantify sea level rise in West Antarctica "because there was so much uncertainty about understanding ice sheet processes and how glaciers will respond over time."
"I think this is a great step to help understand that," he added.
Jordan said the geoengineering and channel blocking suggestions are not logistically feasible at such a remote site.
A simpler solution would be 'tackling climate change'.
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"Ultimately, we will be able to tell governments and policy makers, this is what is going to happen ... in fact we will have a fair and very limited estimate of what will happen to the Thwaites Glacier," Jordan said.
Once scientists can demonstrate the expected sea level rise related to West Antarctica, he said, they will have more evidence when they call for action to mitigate climate change.
The team collected data from the glacier and the adjacent Dotson and Crosson ice shelves from January to March 2019. The exceptional breakdown of sea ice in early 2019 allowed the icebreaker to survey more than 2,000 square kilometers of seafloor in front of glacier ice.
The studied area had been hidden under part of the floating ice shelf that extends from the Thwaites Glacier, which broke in 2002, and was then often inaccessible due to thick sea ice.
Glacier