An ice sheet in West Antarctica is breaking from the inside out.
(From Scientific American / by Scott Waldman)– The significant new findings published yesterday in Geophysical Research Letters show that the ocean is melting the interior of the Pine Island Glacier, which is about the size of Texas. The crack seems to be accelerating, said Ian Howat, associate professor of earth sciences at Ohio State University and the study’s lead author. The findings are the first confirmation of something glaciologists have long suspected was happening, he said.
“It’s showing a new weakness in the ice shelf, and it’s showing the weakness may be extending far up the glacier,” he said. “That’s the alarming thing from our standpoint.”
Higher ocean temperatures are causing the ice to shrink at an accelerating rate, and it’s eroding the ice fringing the continent. That, in turn, opens the ice sheet to further contact with warmer ocean water and increases the amount of ice running into the ocean, the researchers found.
“More importantly, it gives us a mechanism for even faster retreat in the future. Before, we used to have a slow retreat at the edges of the ice shelf,” Howat said. “The ocean had to nibble away at it on the edges. This allows the ice shelf to break apart way further inland from the inside out.”
This latest retreat is particularly noteworthy because it’s farther inland than anything scientists have previously observed, he said. It also shows that the region could be more vulnerable than previously thought.
If Antarctica were not covered in ice, it would be a series of islands. That means much of the ice in the region is already under constant pressure from the ocean, as its movements dislodge the ice that covers the area between the land masses. Cracking is more likely to occur in the valleys located on the ice sheet, where the ocean is in closer contact with the ice, researchers found.
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