Iceberg Twice the Size of New York City Breaks off From Antarctica

The event was expected and not linked to climate change, researchers say

a deep crack in ice
The crack called Chasm-1 had been dormant for decades until 2012. Now, it has created a new iceberg. British Antarctic Survey

A massive 600-square-mile iceberg separated from Antarctica last week in the second major break-away—or calving—from the area in the past two years. Scientists say the event was expected and not related to climate change, per a statement from the British Antarctic Survey (BAS).

“Large ice sheets around Antarctica do occasionally calve large icebergs, just as part of the natural process of the ice moving towards the sea,” Grant R. Bigg, an Earth systems scientist at the University of Sheffield in England, tells Newsweek’s Jess Thomson. “It has been known for some years a rupture would occur, and there have been significant size icebergs from this area before.”

Natural cracks had been forming in the region, known as the Brunt Ice Shelf, for years, but the iceberg finally broke free when a crack called Chasm-1 “fully extended through the ice shelf” on January 22, per the BAS. The crack had lain dormant for at least 35 years until 2012, when researchers began detecting changes. Out of concern for its nearby Halley VI Research Station, the BAS moved the site away from the chasm in 2016 to avoid it being cut off. Glaciologists say the station was unaffected by the recent calving event.

Map of Brunt Ice Shelf in Antarctica
Map of Brunt Ice Shelf in Antarctica British Antarctic Survey

The new iceberg, officially named A81, is slightly larger than A74, which detached from the same ice shelf in 2021 and drifted into the Weddell Sea. BAS researchers expect A81 will follow A74’s path in the Antarctic Coastal Current, which flows to the west. Prior to these two icebergs, the last large piece to break off the Brunt Ice Shelf calved in 1971, per BBC News’ Jonathan Amos. 

While a 600-square mile ice chunk weighing about 500 billion tons may seem enormous, “it is far from being the largest iceberg ever seen, which rivaled Long Island [about 1,400 square miles],” Ted Scambos, a senior research scientist at the University of Colorado at Boulder, tells the Washington Post’s Dan Stillman.

a large chunk breaks off of the Brunt Ice Shelf in Antarctica
Chasm-1 recently led to the breakoff of a 600-square-mile iceberg. European Union, Copernicus Sentinel-2 imagery

The breakoff of A81 was the result of natural processes, but climate change has made ice shelf disintegrations elsewhere in Antarctica more common. Last March, temperatures some 70 degrees Fahrenheit above normal contributed to the Conger Ice Shelf collapse on Eastern Antarctica. From 1995 to 2002, warm temperatures led to a series of disintegration events on the continent’s Larsen Ice Shelf, which shrank from 33,000 square miles down to 26,000 square miles during that time. 

At least one part of the remaining Brunt Ice Shelf is vulnerable to calving, per Newsweek, but researchers will continue to monitor it “to ensure it is safe and to maintain the delivery of the science we undertake at Halley,” Dominic Hodgson, a glaciologist with the BAS, says in the statement.

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