Giant Iceberg Twice the Size of New York City Breaks from Antarctica

A gargantuan iceberg twice the size of New York City has broken off from an ice sheet in Antarctica.

The iceberg, which has an area of nearly 600 square miles, finally broke away from the 490-foot-thick Brunt ice shelf in Antarctica sometime between 2:00 PM and 3:00 PM ET on Sunday.

This "calving," as the break-away of icebergs is known, came after years of cracks naturally forming on the ice sheet. The final blow occurred when a crack called Chasm-1 fully broke through the entire layer of ice.

new iceberg Antarctica
A picture of the Brunt ice shelf (left) and a satellite image of the shelf from space, with the rough area of the new iceberg that broke off drawn on in red, following the path of Chasm-1. The exact shape of the new iceberg will be confirmed by satellite in the coming days. British Antarctic Survey / NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey.

Antarctica is the coldest and driest continent on Earth, containing around 70 percent of the planet's freshwater frozen inside enormous ice sheets. Antarctica is considered a desert, receiving only around 8 inches of precipitation each year at the coasts, with even less inland. It holds the record for the coldest place on planet Earth, with temperatures of -128.6 F having been measured on July 21, 1983, on the Antarctic Plateau, at the then-Soviet-operated Vostok station. Coastal temperatures can rise as high as 50 F in summer months.

"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 emeritus professor of Earth system science at the University of Sheffield in the U.K., told Newsweek.

The breakaway of this section has been expected for a while, so its eventual occurrence comes as no surprise.

"It has been known for some years a rupture would occur, and there have been significant size icebergs from this area before," Bigg said.

At nearly 600 square miles across, this iceberg is nearly twice as large as New York City, which has an area of 302.6 square miles.

brunt ice sheet on January 30, 1986
brunt ice sheet on January 23, 2019
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NASA satellite images showing the growth of the Brunt ice shelf between January 30, 1986 and January 23, 2019.

"A piece of ice the size of Greater London might seem enormous, but this is actually a medium-sized iceberg by Antarctic standards. I recall we have seen a few similar sized ones in the last couple of years," Adrian Luckman, a professor of glaciology and remote sensing at Swansea University in the U.K, told Newsweek.

A similarly sized iceberg, named A74, broke off from the sheet in February 2021, further to the east. According to the British Antarctic Survey, A74, which measured 490 square miles, has now drifted into the Weddell Sea.

The largest iceberg ever recorded was named B-15, and broke off from Ross Ice Shelf of Antarctica in March 2000 measuring a massive 4,247 square miles, about the same size as the island of Jamaica.

The calving of icebergs like this from large ice sheets can sometimes trigger other chunks to free themselves too.

"Whether this calving has any impact on the ice sheet itself will depend upon how the rest of the shelf reacts to the changes that have just occurred. In any event the impact is likely to be small and will take some time to be felt," Luckman said.

Luckman explained that there is at least one part of the remaining shelf, about half of the size of the new iceberg that is now vulnerable to calving.

"We will be watching closely to see if that stabilizes, or more likely also calves away in the next few weeks," he said.

The rest of the ice sheet will be relatively unaffected, however.

"This is unlikely to have a large impact on the grounded part of the ice sheet," Hilmar Gudmundsson, a professor of glaciology at Northumbria University in the U.K., told Newsweek.

"It might cause some changes in [ice flow] velocities across the ice shelf, but I'm not expecting this to have an impact on the upstream grounded ice feeding the ice shelf."

While climate change and the warming atmosphere have led to many cases of glaciers and ice sheets melting prematurely, experts agree that this particular calving is part of the natural cycle of the Antarctic ice sheet. Indeed, the Brunt ice shelf had reached a larger size than it had for many years, meaning that a significant calving was due.

"Brunt ice shelf has just transitioned from one of its largest known extents to one of its smallest," Luckmann said. "But this is just the way that ice shelves work, and there is no evidence that climate change has hastened this particular calving event."

Gudmundsson agreed: "Ice shelves lose mass by periodically large chunks breaking off. This is a natural and regular occurrence."

The new iceberg is due to be named by the U.S. National Ice Center, and is likely to follow the path of A74 as it drifts into the ocean.

Scientists in Antarctica will monitor the ice sheet for any further activity.

"Our science and operational teams continue to monitor the ice shelf in real-time to ensure it is safe, and to maintain the delivery of the science we undertake at Halley [Research Station]," Dominic Hodgson, a British Antarctic Survey glaciologist, said in a statement.

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Update 01/24/23, 9:18 a.m. ET: This article was updated with a statement from Dominic Hodgson.