World’s largest iceberg A23A breaks apart in Antarctic death spiral, unlikely to survive past November

The world’s largest and longest-lasting iceberg, known as A23A, is breaking apart, shrinking steadily, and is unlikely to survive beyond November, scientists say. As per an AP report, the colossal ice formation, which has drifted from Antarctica for decades, is now fracturing into smaller pieces in what experts describe as a “death spiral.”

“It’s an interesting thing to watch, certainly not unprecedented,” said University of Colorado ice scientist Ted Scambos in an interview with The Associated Press Thursday. “But every time these happen, it’s sort of a big spectacular event.”

While the melting of floating ice shelves like A23A does not directly raise sea levels, their disappearance accelerates the flow of land-based glaciers into the ocean, which contributes to rising seas over time.


A23A originally calved from the Filchner-Ronne Ice Shelf in Antarctica in 1986, along a massive crack known as the “Grand Chasm,” first observed in the 1950s. For decades, it hovered near the continent, largely stable, until recent years when it began drifting north to the waters around South Georgia Island, a region scientists describe as a final resting place for massive icebergs.

Earlier this year, A23A was roughly the size of Rhode Island and weighed a trillion tons. It has now shrunk to the size of Houston and continues to lose mass rapidly. The world’s largest iceberg today is D15A, which is nearly twice the size of the diminished A23A, according to Andrew Meijers of the British Antarctic Survey.

A23A has already produced smaller offshoots, designated A23D, A23E, and A23F. NASA satellite imagery Thursday captured these fragments, along with the main body, only days before further detachment.

“It’s still quite thick, but it’s a lot thinner than it was when it left the continent,” Scambos said. “And so now it’s being flexed by long-period waves, by tides, which sweep across the area. And with that flexing, even though it’s incredibly gentle and subtle, it’s finding weak spots in the iceberg, and those are breaking off.”

Meijers warned that the iceberg’s fragmentation will accelerate. “As the iceberg moves further north and the Antarctic spring begins, by the end of the season, A23A will likely rapidly fall apart into chunks too small to track,” he said via email.

Scambos added that if A23A survives the Antarctic spring, the summer heat could trigger an even more dramatic collapse. “It will look sort of like an avalanche that’s floating and could even fall apart in a single day,” he said.

Back in January, Meijers, who visited A23A at the end of 2023, described it as a staggering sight. “The iceberg itself is colossal and it stretches from horizon to horizon … It’s a huge wall, a Game of Thrones style wall of ice that towers above the ship,” he said.

Both Meijers and Scambos emphasised that the birth and decay of megabergs is a natural, long-standing process. The breaking apart of icebergs near South Georgia Island is driven by currents and warmer waters, a cycle that has been occurring for centuries.

With inputs from agencies