In a fascinating turn of events, the world’s largest and oldest iceberg, known as A23a, has run aground off the island of South Georgia.
This colossal block of ice, which is twice the size of Greater London, weighs nearly a trillion tons.
Its grounding has captured global attention as it rests on the continental shelf of the British overseas territory in the South Atlantic Ocean, home to a variety of wildlife including elephant seals, fur seals, king penguins, and many unique bird species.
A Journey Across the Southern Ocean
A23a, which originated from Antarctica’s Filchner Ice Shelf in 1986, spent over 30 years grounded on the ocean floor of the Weddell Sea before it started drifting in 2020.
The iceberg has since been carried by Southern Ocean currents towards South Georgia.
Due to the warming waters and the force of waves and tides, scientists predict that the iceberg will eventually break up into smaller chunks and melt over time.
Potential Hazards and Benefits for Local Wildlife
While fishing vessels operating in the region could face “potentially hazardous” conditions as the iceberg breaks into smaller pieces, there are positive side effects too.
Scientists believe that the nutrients released from the melting iceberg could have a beneficial impact on the local ecosystem, including providing a food boost for penguins and seals in the area.
Close Monitoring of A23a’s Impact
The British Antarctic Survey (BAS) has been keeping a close eye on A23a’s movements, especially since 2023 when it shifted from the Weddell Sea into the wider South Atlantic.
Before it grounded, the iceberg was stuck in a “Taylor column” for several months, which kept it spinning in place.
Since March 1, it has been completely stationary, grounded around 56 miles from South Georgia.
Impact on Fishing and Ecosystem
According to Dr. Andrew Meijers, an oceanographer with the BAS, the iceberg’s presence may not significantly affect the local wildlife if it stays grounded.
However, commercial fishing operations could face disruption as the iceberg breaks apart.
The nutrients released from the grounding and subsequent melt may stimulate the local food web, benefiting the region’s penguin and seal populations.
A Towering Iceberg
Icebergs of A23a’s size are relatively rare, and Dr. Meijers recalls that during a research trip aboard the RRS Sir David Attenborough (famously known as Boaty McBoatface), it took nearly a full day to sail along the length of the iceberg in 2023.
The sheer scale of the iceberg is awe-inspiring, with its towering wall stretching across the horizon.
The Bigger Picture
While the presence of megabergs like A23a is part of the natural lifecycle of Antarctic ice sheets, the role of human-driven climate change in accelerating the melting and loss of ice mass from these shelves cannot be ignored.
The ongoing impact of climate change is likely contributing to the instability of ice shelves and the increased frequency of large icebergs like A23a breaking off from Antarctica.