Satellite images show near-collision of giant iceberg in Antarctica

The drifting iceberg could have triggered the release of an even bigger one, scientists say

Holly Bancroft
Tuesday 24 August 2021 09:30
Iceberg nearly collides with Antarctic ice shelf
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An iceberg, one and a half times the size of Paris, narrowly avoided colliding with its parent ice shelf in Antarctica, a series of satellite photos show.

The near-miss prevented the release of an even bigger berg, which is still precariously attached to the rest of the ice.

The iceberg calved from Antarctica's Brunt Ice Shelf in February of this year after a dramatic crack formed on the shelf in November 2020.

It was the third major split to tear across the ice shelf in the last decade. The iceberg, called A74, has been sticking close to the shelf for six months due to ocean currents, the European Space Agency said in a statement.

New images from the agency showed the iceberg swinging near the shelf, which has already been weakened by severe cracks and rifts.

Announcing the close shave, The European Space Agency (ESA) said: “In early August, strong easterly winds have spun the iceberg around the western tip of Brunt, brushing slightly against the ice shelf before continuing southwards.

“Had the drifting iceberg hit the unstable ice shelf with severe force, it may have triggered the release of a new 1,700 square kilometer [656 square mile]-sized iceberg”, even bigger that the A74.

ESA’s Mark Drinkwater said: “The nose-shaped piece of the ice shelf, which is even larger than A74 remains connected to the Brunt Ice Shelf, but barely. If the berg had collided more violently with this piece, it could have accelerated the fracture of the remaining ice bridge, causing it to break away.”

Despite the close shave, dangers to the Brunt Ice Shelf continue. The glacial region that narrowly escaped being hit by the A74 iceberg is “tenuously attached” to the seabed, according to the ESA.

Glaciologists are studying the area and watching rifts and chasms in the ice shelf.

“With the ice shelf deemed unsafe due to the encroaching cracks in 2017, the British Antarctic Survey closed their Halley VI Research Station and re-positioned it to a more secure location,” The ESA said. “Halley is made up of eight interlinked pods built on skis, which allows the pods to be easily moved in case of unstable ice or new chasms forming on the ice shelf.”

The entire region is under threat from global warming and temperatures are up to 3 degrees Celsius higher than in the 1950s. However scientists don’t think these particular events were directly caused by climate change.

Laura Gerrish, a researcher at the British Antarctic Survey, said: “A74 [is] just part of the natural cycles on ice shelves that hadn’t calved anything big for decades. It’s important to monitor the frequency of all iceberg carving, but these are all expected for now.”

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