Two Antarctic glaciers are breaking free from their respective areas, increasing the threat of large-scale sea-level rise.
Located along the coast of the Amundsen Sea in West Antarctica, the enormous Pine Island and Thwaites glaciers already contribute around 5% of global sea-level rise. The survival of Thwaites has been deemed so critical that the U.S. and U.K. have launched a targeted multimillion-dollar research mission to the glacier. The loss of the glaciers could trigger the broader collapse of the West Antarctic ice sheet, which contains enough ice to eventually raise seas by about 10 feet, the Washington Post noted.
The Thwaites glacier on its own has the potential to raise global sea levels by more than two feet, according to NASA estimates.
The new findings, published Monday in the Proceedings of the National Academy of Sciences, come from an analysis of satellite images. Concerns grow as the natural buffer system that prevents the glaciers from flowing outward rapidly is breaking down, potentially unleashing far more ice into the sea.
The glaciers shear margins where their floating ice shelves experience high levels of friction are weakening and breaking into pieces.
Stef Lhermitte, a satellite expert at Delft University of Technology in the Netherlands, told the Post that “the stresses that slow down the glacier, they are no longer in place, so the glacier is speeding up.”
Lhermitte added, “We already knew that these were glaciers that might matter in the future, but these images to me indicate that these ice shelves are in a very bad state.”
Deep channels discovered under the glaciers are allowing warm ocean water to melt the underside of the ice, CNN reported.
The findings, published in the British Antarctic Survey, show the ocean floor is deeper than previously thought, with more deep channels leading towards the grounding line, where the ice meets the bed.
Dr. Tom Jordan, an aero-geophysicist at British Antarctic Survey, told CNN, “Thwaites Glacier itself is probably one of the most significant glaciers in West Antarctica, because it’s so large, because we can see it’s changing today.”
“We know that its bed dips down, and it gets deeper and deeper underneath the ice sheet, which means that, theoretically, you can get a process called marine ice-sheet instability. And once it starts to retreat, it will just keep retreating,” Jordan said.
The next phase of testing is to incorporate the data from channels — some of them 2,600 feet deep — into simulations of how the ice sheet will respond in the future.
The International Thwaites Glacier Collaboration has not been able to precisely measure the sea-level rise in West Antarctica.