The Conger ice shelf has collapsed just before a record-setting Antarctic heat wave, concerning scientists about what is to come.

East Antarctica saw record temperatures in mid-March. Concordia station, the French-Italian research facility on one of the summits of the Antarctic Ice Sheet more than three kilometers high, recorded a record high temperature for the site on March 18. The -11.8C temperature is over 40 degrees Celsius higher than typical for the southern autumn, and higher even than the previous summer record of -12.6 C.

The collapse of the Conger ice shelf, a sheet of ice covering nearly 500 square miles, was just a few days before that, on March 15. Both events were linked to an atmospheric river bringing warm, moist air down from the southern ocean and trapping it above the continent.

The Conger ice shelf was floating ice, so there is no danger of it raising sea levels, but floating ice shelves have a very important role – they restrain inland ice, slowing its flow into the ocean. As ice shelves continue to erode, the immense quantities of ice that blanket Antarctica, nearly two miles thick in many places, will flow faster into the sea. And that will cause sea level rise. Fortunately, the glacier behind Conger is a relatively small one.

“[This collapse] won’t have huge effects, most likely, but it’s a sign of what might be coming,” said Dr. Catherine Colello Walker, a planetary scientist at NASA and the Woods Hole Oceanographic Institution. According to Walker, the Conger ice shelf shrank by half between January and March, before the collapse.

“Ice shelves lose mass as part of their natural behavior – but the large-scale collapse of an ice shelf is a very unusual event,” said Professor Andrew Mackintosh, of Monash University. “This seems to be a collapse rather than normal behavior.”

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