Fears that the world’s biggest iceberg could hit island in the South Atlantic

The world’s largest iceberg is still on the move and there are fears that it could be headed north from Antarctica towards the island of South Georgia.

The iceberg, called A23a, was previously “trapped” spinning around an undersea mountain for several months, according to Andrew Meijers, a physical oceanographer at the British Antarctic Survey.

Now, it appears that it is moving with the prevailing current towards South Georgia, a British Overseas Territory in the southern Atlantic Ocean.

“It is presently in a meander of the current and not moving directly towards the island,” said Meijers in a statement sent to CNN Thursday. “But our understanding of the currents suggest that it is likely to again move towards the island soon.”

“Icebergs are inherently dangerous. I would be extraordinarily happy if it just completely missed us,” said sea captain Simon Wallace, who spoke to the BBC from the South Georgia government vessel Pharos.

“We have searchlights on all night to try to see ice – it can come from nowhere,” Wallace added.

The iceberg remains the largest in the world, according to measurements updated by the US National Ice Center earlier this month.

Spanning an area of 3,672 square kilometers (1,418-square-miles) when measured in August — slightly bigger than Rhode Island and more than twice the size of London — the A23a iceberg has been carefully tracked by scientists ever since it calved from the Filchner-Ronne ice shelf in 1986.

It remained grounded on the Antarctic’s Weddell Sea floor for more than 30 years, probably until it shrank just enough to loosen its grip on the seafloor.

Then, the iceberg was carried away by ocean currents before it became stuck again in a Taylor column – the name given to a spinning vortex of water caused by ocean currents hitting an underwater mountain.

In December, the iceberg broke free. Initially, scientists said they expected it to continue drifting along the ocean currents and towards warmer water.

At the time, the British Antarctic Survey said the iceberg would likely break up and eventually melt when it reached the remote island of South Georgia.

But for now, at least in satellite images, the iceberg appears to have maintained its structure and is yet to break up into smaller chunks, as previous “megabergs” have done, said Meijers.

It’s now a question of whether the iceberg will follow the current and head for the open South Atlantic or if it will run onto the continental shelf where it would become stuck for some time.

“If this happens, it could seriously impede access to feeding grounds for the wildlife – seals and penguins mostly – that breed on the island,” said Meijers.

Meanwhile, Mark Belchier, director of fisheries and environment for the government of South Georgia and the South Sandwich Islands, told CNN Thursday that he was keeping a close eye on the track of the iceberg. “Whilst they are common at South Georgia, they can cause issues for shipping and fishing vessels in the region,” Belchier added.

Belchier said any potential impacts to wildlife would likely be “highly localized and transient.”

South Georgia and the South Sandwich Islands have a rich biodiversity and are home to one of the world’s largest Marine Protected Areas.

Scientists have said that this particular iceberg probably broke away as part of the natural growth cycle of the ice shelf and not because of the fossil fuel-driven climate crisis. But global warming is driving worrying changes in Antarctica, with potentially devastating consequences for global sea level rise.

CNN’s Issy Ronald contributed reporting.

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