The one-time world’s largest iceberg has run aground in shallow waters off the remote British island of South Georgia.
The iceberg, known as A23a and approximately twice the size of Greater London, appears to be stuck and is expected to break apart along the island’s south-west shores.
Fishermen fear they may face significant challenges navigating through the vast chunks of ice, and there are concerns it could disrupt the feeding patterns of macaroni penguins in the area.
However, scientists in Antarctica suggest that the iceberg could also bring ecological benefits. As it melts, the ice will release vast amounts of nutrients into the ocean, potentially triggering a surge in marine life.
The iceberg’s grounding marks the latest development in a nearly 40-year journey. A23a originally broke away from the Filchner-Ronne Ice Shelf in 1986. For decades, it remained trapped on the sea floor and then in an ocean vortex until it finally began moving northwards in December last year.
Satellite images have tracked the iceberg’s progress through “iceberg alley”-a region of warmer waters-where it has remained remarkably intact. At one point, it appeared to spin in place before accelerating in mid-February, travelling at approximately 20 miles (30 km) per day.
This image from NASA, taken on 21 February 2025 shows the iceberg approaching South Georgia, where it struck the shallow continental shelf.
Once measuring 3,900 sq km (1,500 sq miles), it has steadily shrunk as it moves through warmer waters and is now estimated to be 3,234 sq km.
The tides will continue to lift and lower the iceberg, causing it to grind against the continental shelf. This movement is expected to further erode both the ice and the underlying rock.
