This Antarctic glacier is cracking from the inside out — and that’s bad news for all of us

A massive glacier at the edge of the West Antarctic Ice Sheet is cracking from the inside out at accelerating speed. That’s alarming because this glacier — and others — function like corks in a bottle: they keep the ice from flowing into the sea, which would raise sea levels by several feet.

The glacier, which is described in a paper published yesterday in Geophysical Research Letters, is called Pine Island Glacier. In 2015, a 224-square-mile iceberg broke off from the glacier. After studying satellite images before and after the event, researchers at Ohio State University found that in 2013, a rift formed at the base of the ice shelf, 20 miles inland. The rift worked its way up for two years until it caused the iceberg to break off.

Icebergs do separate from ice sheets in the Antarctic on a fairly regular basis. This one, though, is special. It confirmed what glaciologists have long been suspecting: that the ice shelf is weakening. But it also shows that the ice retreat is happening farther inland than scientists had previously observed.

“It’s generally accepted that it’s no longer a question of whether the West Antarctic Ice Sheet will melt, it’s a question of when,” study leader Ian Howat, associate professor of Earth sciences at Ohio State, said in a statement. If things continue the way they are, glaciers will keep melting, and West Antarctica will significantly collapse “in our lifetimes.”