The world’s largest iceberg, A23a, is drifting toward South Georgia Island, a remote and ecologically vital wildlife haven.
This massive block of ice, about the size of Rhode Island, poses a significant threat to the delicate ecosystem of the island, home to penguins and seals.
Satellite images, including recent data captured by NOAA’s GOES East satellite on Jan. 22, 2025, are closely monitoring the iceberg’s slow journey through the Southern Ocean, where it could soon reach the shallow waters surrounding South Georgia.
Breaking free
Iceberg A23a has been a concern for scientists since it broke away from the Antarctic ice shelf in 1986. After remaining immobile for over three decades, the iceberg finally broke free in 2020 and began drifting northward.
Measuring roughly 1,350 square miles (3,500 square kilometers) across, A23a is the world’s largest and oldest iceberg according to AFP News. Its imposing size and slow, steady movement have captivated oceanographers and researchers alike, though predicting its exact path has proven difficult due to the unpredictable forces of ocean currents.
Unlike many previous “megabergs” that crumble into smaller chunks, A23a has shown little sign of breaking apart, which has only intensified concerns over its collision with South Georgia Island.
According to Andrew Meijers, a physical oceanographer at the British Antarctic Survey, the iceberg is currently moving northeastward, but prevailing currents suggest that it could strike the shallow continental shelf around South Georgia in two to four weeks. If it does, the consequences could be dire for the island’s wildlife Meijers told AFP News.
Potential impact
The potential impact on South Georgia Island’s ecosystem is worrying. Penguins, seals, and other marine animals depend on the island’s surrounding waters for food and breeding. If A23a grounds itself on the continental shelf or disrupts the currents, it could block access to essential feeding areas.
Meijers warned that icebergs have previously grounded near the island, causing significant mortality among penguin chicks and seal pups, particularly when their feeding grounds were cut off by the ice. Such a scenario could hinder the survival of these already vulnerable species, especially during the crucial breeding season.
Hit or miss?
Despite these concerns, there is still a degree of uncertainty surrounding the iceberg’s path. It’s possible that A23a could avoid the shelf and drift into open water, bypassing South Georgia altogether.
Alternatively, the iceberg could become stuck for months or break apart into smaller pieces, both of which could seriously impede seals and penguins trying to feed and raise young on the island, according to Meijers.
Raul Cordero from Chile’s University of Santiago and part of the National Antarctic Research Committee said he was confident the iceberg would not impact South Georgia.
“The island acts as an obstacle for ocean currents and therefore usually diverts the water long before it reaches the island,” Cordero told AFP News.
“The iceberg is moved by that water flow, so the chances of it hitting are not that high,” though chunks could, Cordero said.
Glaciologist Soledad Tiranti, who is currently part of an Argentinian exploration mission in Antarctica, explained that icebergs like A23a are so massive that they typically become grounded on the seabed before reaching an island or the mainland, according to AFP News.
The situation remains fluid, and scientists are keeping a close eye on the iceberg’s progress with regular satellite imagery and ocean monitoring.