World's Largest Iceberg, Weighing Nearly 1 Trillion Tons, Runs Aground Near Sub-Antarctic Island

Mar. 15, 2025

The world’s largest iceberg has run aground off the coast of a remote island in the Atlantic Ocean, according to British researchers.

TheBritish Antarctic Survey(BAS) announced on Tuesday, March 4 that the A23a iceberg is currently grounded on the continental shelf about 90 kilometers (56 miles) from the island of South Georgia in the sub-Antarctic area.

The A23a iceberg is twice the size of Greater London, and slightly smaller than Rhode Island, according toCNN.

Dr. Andrew Meijers, an oceanographer at BAS, said experts do not expect the iceberg, which weighs nearly a trillion tons, to disrupt local wildlife if it remains aground, per BAS. However, he added, it could make operations “more difficult and potentially hazardous” for commercial fisheries.

“It will be interesting to see what will happen now,” Meijers explained. “From a scientific perspective we are keen to see how the iceberg will affect the local ecosystem.”

The A23a iceberg was grounded for more than 30 years after splitting from Antarctica’s Filchner Ice Shelf in 1986, according to BAS.

Meijers said the iceberg “appears to be maintaining its structure and has not yet broken up into smaller chunks, as previous ‘megabergs’ have done.”

“Now it’s grounded, it is even more likely to break up due to the increased stresses, but this is practically impossible to predict.,” Meijers explained. “Large bergs have made it a long way north before … but they all inevitably break up and melt quickly after.”

The A23a iceberg before it ran aground in March 2025.IAN STRACHAN/EYOS Expeditions/AFP via Getty

IAN STRACHAN/EYOS Expeditions/AFP via Getty

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There “could be an upside” to the iceberg running aground, according to Meijers. “If the berg is stimulating ocean productivity, this could actually boost populations of local predators like seals and penguins,” he explained.

“It’s like dropping a nutrient bomb into the middle of an empty desert,” said Professor Nadine Johnston, perBBC News.

Ice shelves have lost around 6 trillion tons of mass since the year 2000, Meijers said, per BAS.

The loss of ice shelf mass, he added, “has significant implications” on the ocean’s circulation “due to the addition of freshwater, acceleration of sea level rise … and possible irreversible ‘tipping points’, particularly in the vulnerable west Antarctic.”

“It’s very surprising to see that A23a has lasted this long and only lost about a quarter of its area," Griffiths said.

source: people.com