Meltwater could undermine the walls of ice holding back Antarctica’s glaciers, scientists reported on Wednesday, a finding that underscores concern about the potential for a significant sea level rise. The ice shelves, formed over thousands of years, serve as dams to prevent much of the continent’s snow and ice from flowing toward the ocean. Scientists found that about 60% of the ice shelf area is vulnerable to a process call hydrofracturing, in which meltwater seeps into the shelves’ crevasses, some of which are hundreds of meters deep, and triggers collapse.
“This meltwater is heavier than ice, so it can penetrate through the entire ice thickness, just like a knife,” said climate scientist Ching-Yao Lai at Colombia University. The new study, published in the journal Nature, used AI to identify ice-fracture features in nearly 260 satellite images of 50 ice shelves across the continent. Those ice shelves surround about 75% of the Antarctic coastline. Finding vulnerabilities in the ice shelves buttressing the glaciers above was a surprise, Lai said. “Previously, we thought there are going to be places vulnerable to hydrofracture, but that those places might not matter at all for the ice sheet,” Lai said.
In Antarctica, if “we start seeing the collapse of some of this ice that is there like a wall holding back everything behind it, it’s just going to accelerate the pace of sea level rise beyond what we’re probably predicting right now,” said Alexandra Isern, head of Antarctic studies for the U.S. National Science Foundation who was not involved in the study. Once gone, the ice shelves wouldn’t be able to form again “in any time we’ll ever see,” Isern said. “It took a long time to make them, and it maybe isn’t going to take as long to get rid of them.”
Source: Trust
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