Where will the world’s largest iceberg end up?

(Paris) Tracked by satellites, the largest iceberg in the world – 80 kilometers long – is currently drifting from Antarctica towards a remote island where it could, in the worst case, run aground and block the penguins and sea lions who are reproduce there.

This immense ice plateau – 30 times larger than Paris – which has been moving away from Antarctica for years, is now heading towards the British island of South Georgia, an important site for the reproduction of wildlife.

The iceberg, unlike previous giant icebergs, does not seem to be breaking up into smaller pieces as it drifts, Andrew Meijers, an oceanographer at the British Antarctic Survey, told AFP on Friday.

According to the expert, it is difficult to accurately predict its trajectory, but prevailing currents suggest that this colossus will reach the edge of the continental shelf around South Georgia within two to four weeks.

What might happen next remains unclear.

The iceberg could avoid the continental shelf and be carried into the deep waters of the South Atlantic, beyond South Georgia, a British Overseas Territory located about 1,400 km east of the Falkland Islands .

But it could also hit the inclined bottom, remain stuck for months, or even break into several pieces and create obstacles for sea lions and penguins.

“It would be quite dramatic, but not unprecedented,” said the expert. “Icebergs have run aground here in the past, causing significant mortality among penguin chicks and young sea lions.”

But for a Chilean expert interviewed by AFP, Raul Cordero of the University of Santiago, “the chances of collision are not very high”, of the order of “less than 50%”, the island having a tendency to deflect water and ocean currents which, in turn, could deflect the iceberg.

“Pieces” could perhaps hit the island “but the iceberg as a whole, that would be astonishing,” judges this member of the Chilean Antarctic research program.

No worries even from Soledad Tiranti, a glaciologist specializing in nautical safety, currently aboard the Argentine icebreaker ARA Almirante Irízar, in the middle of the Antarctic summer campaign.

“They are very deep blocks of ice and generally before approaching an island or continent, they run aground due to the simple fact that near the island there is less depth,” says the Argentinian glaciologist at the ‘AFP.

“Huge white cliff”

Spanning approximately 3,500 square kilometers, the iceberg called A23a is the oldest in the world. It broke away from the Antarctic ice shelf in 1986.

It then remained stuck on the seafloor for more than 30 years before breaking free in 2020, beginning its slow drift northward. It remained several months in 2024 in the same place, rotating on itself.

Andrew Meijers, who observed A23a up close in late 2023, describes it as “a huge white cliff, 40 to 50 meters high, stretching as far as the eye can see.”

“It’s like a gigantic white wall that reminds us “Game of Thrones”, it feels like it’s endless,” he added.

The gigantic block of fresh water is driven by the world’s most powerful ocean current, the Antarctic Circumpolar Current, at 20 centimeters per second, according to the British Antarctic Survey.

The iceberg follows “more or less a straight line” to South Georgia, says Andrew Meijers.

An obstacle for animals

The researcher’s fear is linked to the fact that during the austral summer, along the southern coasts of South Georgia, penguins and sea lions go on expeditions into cold waters to bring back enough food for their young.

“If the iceberg gets stuck there,” explains Andrew Meijers, “the animals might be forced to go around it. This would cause them to expend much more energy, which means fewer resources for the young and therefore an increase in mortality. »

Especially since the island’s sea lions and penguins are already experiencing a “bad season” due to avian flu.

When A23a eventually melts, it could generate smaller icebergs, but still dangerous for fishermen.

However, it will also bring nutrients into the water, promoting phytoplankton, an essential food source for whales and other marine life.

Although the formation of icebergs is a natural phenomenon, Andrew Meijers believes that their accelerated loss in Antarctica is likely due to human-caused climate change.