The ‘world’s biggest iceberg’, “A23a iceberg“, which is more than twice the size of London, is drifting toward South Georgia Island, raising concerns among scientists that it could disrupt the feeding patterns of young penguins and seals.
The massive ice block is slowly moving from Antarctica and could collide with South Georgia, a vital wildlife breeding ground in the South Atlantic.
What is A23a iceberg?
The massive A23a iceberg, covering around 3,500 square kilometers (1,350 square miles), broke off from the Antarctic shelf in 1986 and remains the world’s largest and oldest iceberg.
After remaining stationary for more than three decades, it finally began moving in 2020, with its northward progression occasionally hindered by oceanic forces causing rotational movements.
Andrew Meijers, a physical oceanographer at the British Antarctic Survey, told news agency AFP that satellite observations indicate the “megabergs” has maintained its integrity, unlike previous large icebergs that typically fragment into smaller pieces whilst traversing the Southern Ocean.
Meijers noted that while the iceberg’s exact path remains uncertain, current projections suggest it could reach South Georgia’s continental shelf within two to four weeks.
What does it look like?
During a scientific expedition in late 2023, Meijers encountered the iceberg directly, describing it as “a huge white cliff, 40 or 50 metres high, that stretches from horizon to horizon”.
“It’s just like this white wall. It’s very sort of Game of Thrones-esque, actually,” he said, referencing the television series.
What might happen next?
The iceberg may drift past the continental shelf into open waters beyond South Georgia, a British overseas territory located about 1,400 kilometers (870 miles) east of the Falkland Islands.
Alternatively, it could collide with the sloping seabed, potentially becoming lodged for months or fragmenting into smaller pieces.
If the latter occurs, Meijers warned it could severely disrupt feeding and breeding for seals and penguins on the island.
“Icebergs have grounded there in the past and that has caused significant mortality to penguin chicks and seal pups,” he added.
Weighing just under a trillion tonnes, this colossal block of freshwater is being carried by the Antarctic Circumpolar Current, the world’s most powerful ocean jet stream.
What will happen if the ‘megaberg’ hits the Island?
During South Georgia’s summer, penguins and seals along the southern coast hunt in the icy waters to feed their young. “If the iceberg parks there, it’ll either block physically where they feed from, or they’ll have to go around it,” Meijers told AFP.
“That burns a huge amount of extra energy for them, so that’s less energy for the pups and chicks, which causes increased mortality,” he added.
However, their populations are already struggling due to a bird flu outbreak, and the approaching iceberg could further worsen the situation, the expert continued.
The iceberg’s eventual melting could benefit the ecosystem by releasing nutrients that promote phytoplankton growth, supporting whale populations and enabling research into carbon dioxide absorption patterns.
Whilst icebergs occur naturally, Meijers noted that Antarctica’s ice loss rate has increased, potentially due to anthropogenic climate change.
What are the chances of the iceberg hitting?
Raul Cordero, affiliated with Chile’s University of Santiago and the National Antarctic Research Committee, expressed confidence that A23a would avoid South Georgia.
“The island acts as an obstacle for ocean currents and therefore usually diverts the water long before it reaches the island,” he said.
“The iceberg is moved by that water flow, so the chances of it hitting are not that high,” though chunks could, he added.