600-square-mile iceberg, about the size of two New York cities, breaks off from Antarctica’s ice shelf

One of the planet’s most closely monitored ice shelves has just undergone a major transformation. A huge chunk of the Antarctic Brunt Ice Shelf — a chunk the size of two New York cities — broke loose on Sunday.

The British Antarctic Survey said Monday the iceberg is 1,550 square kilometers, or just under 600 square miles.

This is the second major ice shelf break-off, called calving, in two years, although scientists have long predicted it. According to the British Antarctic Survey, cracks have been developing naturally throughout the ice shelf for a decade.

The Brunt Ice Shelf faces the Weddell Sea from the site of another headline-grabbing ice shelf, the Larsen C Ice Shelf on the Antarctic Peninsula. Last year, the Larsen C Ice Shelf – which was about the size of New York City and long considered stable – plunged into the sea.

It was the first time in human history that Antarctica had such a collapse. It happened after one atmospheric flow brought unusually warm air to the region, and many pointed to climate change as a possible contributing factor.

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This map of Antarctica shows the location of various Antarctic ice shelves.

Agnieszka Gautier, National Data Center for Snow and Ice


But according to BAS glaciologist Dominic Hodgson, Brunt’s recent iceberg break-off “is not linked to climate change”.

“This calving event was expected and is part of the natural behavior of the Brunt Ice Shelf,” Dodgson said.

A large crack in the Brunt Shelf known as the Chasm had been dormant for decades, but in 2012 scientists discovered a major change. As of 2015, it was growing steadily, and by December last year, researchers said it “extended the entire ice shelf.”

This is the second time in two years that an iceberg has calved from the ice shelf.

The last one, known as A74, was formed in February 2021 – not even 5 years after a new crack called Halloween Crack formed. It is slightly smaller than the last crash and has since drifted into the Weddell Sea.

The newest iceberg is named by the US National Ice Center. Researchers think it will likely follow the path of the A74 into the sea.

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