Scientists have discovered a series of worrying weaknesses in the ice shelf holding back one of Antarctica’s most dangerous glaciers, suggesting that this important buttress against sea level rise could shatter within the next three to five years.
Until recently, the ice shelf was seen as the most stable part of Thwaites Glacier (shown on the left of the image above). Because of this brace, the eastern portion of Thwaites flowed more slowly than the rest.
Satellite images show several large, diagonal cracks extending across the floating ice wedge.
These weak spots are like cracks in a windshield, said Oregon State University glaciologist Erin Pettit. One more blow and they could spiderweb across the entire ice shelf surface. “This eastern ice shelf is likely to shatter into hundreds of icebergs,” she said. “Suddenly the whole thing would collapse.”
Even if the fractures don’t cause the shelf to disintegrate, it is likely to become completely unmoored from the seafloor within the next decade.
But when the shelf fails, the eastern third of Thwaites Glacier will triple in speed, spitting formerly landlocked ice into the sea. Total collapse of Thwaites could result in several feet of sea level rise, scientists say, endangering millions of people in coastal areas.
Without its protective ice shelf, scientists fear that Thwaites may become vulnerable to ice cliff collapse, a process in which towering walls of ice that directly overlook the ocean start to crumble into the sea. This process hasn’t been observed in Antarctica.