The World's Largest Iceberg Is On The Move Again!

After spending months spinning in the Antarctic waters, A23a, the world’s largest iceberg, is on the move again. This massive chunk of ice covers 1,418 square miles (3,673 sq. km). This is more than twice the size of the city of London. It weighs over a trillion tons and is about 1,312 feet (400 m) thick.

A23a is one of three pieces of a larger iceberg called A23, which broke off from Antarctica's Filchner Ice Shelf in 1986. The other two floated away and eventually melted. But A23a got stuck in the Weddell Sea in the Southern Ocean for over 30 years. In 2020, the iceberg finally broke loose and began moving at about three miles (4.8 km) daily.

Scientists expected A23a to drift into "iceberg alley" in the South Atlantic and melt. However, in August 2024, it became trapped again — this time in a spinning column of water in the Southern Ocean. The iceberg rotated about 15 miles a day, but otherwise remained in place.

A23a finally broke free in December 2024 and began heading toward the island of South Georgia in the South Atlantic. This remote island is home to a wide variety of animals, including vast colonies of four penguin species, as well as fur seals and elephant seals. Once again, researchers expected the iceberg to break up and melt long before reaching South Georgia. However, satellite images from January 24, 2025, showed that the iceberg was intact.

"A23a is the iceberg that just refuses to die," said Professor Mark Brandon, an Open University polar scholar. "Usually, you think of icebergs as being transient things; they fragment and melt away. But not this one."

A23a is expected to reach the shallow continental shelf near South Georgia within two to four weeks. It could then either follow the ocean currents into the open South Atlantic or collide with the continental shelf and get stuck again. If this happens, A23a will trap South Georgia's animals, preventing them from getting food in the open water.

However, Raul Cordero from Chile's University of Santiago is confident the iceberg will bypass South Georgia without causing harm.

"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."

Hopefully, Cordero is right, and A23a will be carried away by ocean currents and melt safely in the South Atlantic.

Resources: CNN.com, CBSnews.com, BBC.com