World's largest iceberg is on a collision path with remote islands

Megaberg A23a might be on the verge of running into South Georgia and surrounding islands in the South Atlantic. The result could spell trouble for wildlife on those islands, and A23a's movement is a predictor of more similar occurrences as climate change worsens.

The iceberg cometh

The spinning iceberg is approximately 1,500 square miles in size and located about 173 miles from the islands. If A23a grounds and wedges in the waters close to the islands, it "stands to endanger millions of penguins, seals and rare marine species not found anywhere else on Earth," said Science Alert. Specifically, the iceberg would block the animals' abilities to feed themselves and their young, which would lead to mass deaths.

This is not the first time an iceberg has posed a threat to South Georgia. In 2004, iceberg A38 "grounded on its continental shelf, leaving dead penguin chicks and seal pups on beaches as massive ice chunks blocked their access to feeding grounds," said the BBC. In 2023, iceberg A76 came close to grounding. "We are interested to see if it will take the same route the other large icebergs that have calved off Antarctica have taken. And more importantly what impact this will have on the local ecosystem," Andrew Meijers, an oceanographer at the British Antarctic Survey, said in a press release.

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A23a broke from the Filchner-Ronne Ice Shelf in 1986. It did not do much during the first few decades of its freedom. "Gradual melting allowed it to begin inching towards the Southern Ocean in 2020, breaking loose in 2023, only to become trapped by a swirling vortex of water," said Science Alert. "The circulating currents that result can make it difficult for icebergs to break free, but the trillion-ton A23a did just that, and scientists continue to closely monitor it."

Along with a risk to the island ecosystem, the iceberg can have a significant impact on the ocean ecosystem. As the iceberg moves, it melts slowly and surely. "Past research has shown a boost in iron from melting glaciers can increase phytoplankton levels, for example, trapping a portion of CO2 from the atmosphere," said Science Alert. The iceberg could reach the islands sometime in the coming weeks.

Watery predictions

Icebergs are notoriously unpredictable. There is a chance the iceberg will not even collide with South Georgia. "It could avoid the shelf and get carried into open water beyond South Georgia," said The Guardian. "Or it could strike the sloping bottom, getting stuck for months or break up into pieces." If it does wedge in the islands, "impacts are to be expected for both fisheries and wildlife," but "both have a great capacity to adapt," Mark Belchier, a marine ecologist who advises the South Georgia government, said to the BBC.

The region is known as "iceberg alley," so it is no stranger to icebergs, but that does not mean that there is no cause for concern. "This iceberg is a natural phenomenon, but it really does represent an increase in the ice loss of Antarctic ice shelves," Meijers said to Yahoo News. "Since 2020, the ice shelves have lost six trillion tons of ice," and "that's due to climate change."