World's Largest Iceberg A23a Rapidly Disintegrating After Years at Sea

A photograph obtained from social media shows the world's largest iceberg, A23a, in Antarctica on January 14, 2024. Earlier this year, the iceberg weighed nearly a trillion tonnes and was more than twice the size of Greater London.

The massive iceberg, composed of frozen freshwater, posed a brief threat to penguin feeding grounds on a remote island in the South Atlantic Ocean. However, it has since moved on.

According to analysis of satellite images, A23a is now less than half its original size, but still measures 1,770 square kilometers and 60 km at its widest point. Large chunks have broken off in recent weeks, with smaller pieces scattered around it, posing a potential hazard to ships.

Andrew Meijers, a physical oceanographer from the British Antarctic Survey, noted that the iceberg is "breaking up fairly dramatically" as it drifts further north. He believes it is "rotting underneath" due to the warmer water and expects it to continue melting, potentially becoming unidentifiable within weeks.

A23a originated from the Antarctic shelf in 1986 but became grounded in the Weddell Sea, remaining stuck for over three decades. It finally broke free in 2020 and was carried into the South Atlantic Ocean by the Antarctic Circumpolar Current.

Around March, the iceberg ran aground near South Georgia island, raising concerns about disrupting penguin and seal colonies. However, it dislodged in late May and continued its journey. Satellite images show that the iceberg has been accelerating, sometimes traveling up to 20 km per day.

Exposed to warmer waters and large waves, A23a has been rapidly disintegrating. Scientists were surprised by its longevity, as most icebergs do not travel as far. However, once icebergs leave the cold waters of Antarctica, they are destined to melt.

Iceberg calving is a natural process, but scientists believe the rate of loss from Antarctica is increasing, likely due to human-caused climate change.