New York-sized ice shelf collapses in previously stable East Antarctica

An ice floe the size of New York has collapsed in East Antarctica, an area long thought to be stable and little affected by climate change, worried scientists said on Friday.

The collapse, captured by satellite images, marked the first time in human history that the frigid region has experienced a sea ice collapse. It came at the start of a monstrous heat spell last week, when temperatures soared more than 40C above normal in parts of East Antarctica.

Satellite photos show the area has shrunk rapidly over the past two years, and now scientists say they are wondering if they have overestimated East Antarctica’s stability and resilience to the warming climate that has caused quickly melt the ice on the short west side and the vulnerable peninsula.

The pack ice, about 1,200 square kilometers holding the Conger and Glenzer glaciers back from warmer water, collapsed between March 14 and 16, said ice scientist Catherine Walker of the Woods Hole Oceanographic Institute. She said scientists had never seen this happen in this part of the continent and it was worrying.

“The Glenzer Conger Ice Shelf was probably there for thousands of years and it will never be there again,” said University of Minnesota ice scientist Peter Neff.

The problem is not the amount of ice lost in this collapse, Neff and Walker said. It is negligible. But it’s more about where it happened.

Neff said he was concerned that previous assumptions about the stability of East Antarctica were not so accurate. And that’s important because frozen water in East Antarctica if it melted – and it’s a process that lasts millennia if not longer – would raise seas around the world by more than 50 metres. That’s more than five times the ice of the more vulnerable West Antarctic Ice Sheet, where scientists have focused much of their research.

Scientists had seen the sea ice shrink quite a bit since the 1970s, Neff said. Then in 2020, shelf ice loss accelerated to lose about half of itself every month or so, Walker said.

“We’re probably seeing the result of long-standing increased ocean warming there,” Walker said. “it just melted and melted.”

And then last week’s warming “is probably something like, you know, the last straw on the camel’s back.”