27 January 2025

The world’s largest iceberg, A23a, is heading for South Georgia Island, the home of millions of penguins including king penguins (Aptenodytes patagonicus) shown above, and macaroni penguins (Eudyptes chrysolophus) listed as Vulnerable and pictured below. If the iceberg gets trapped near the island while it melts, it may block their access to food.

A23a iceberg broke off of Antarctica in 1986 but it didn’t move for about 30 years while it was hung up on the bottom of the Weddell Sea. When it floated free it was captured by a spinning current called a Taylor column. Finally in 2024 it broke free again and started to move.

It’s hard to imagine the size of this iceberg without comparisons. Right now it’s nearly the same size as Rhode Island.

And its ice is 920 feet thick, which is taller than Pittsburgh’s US Steel Tower at 841 feet. I’ve added a yellow arrow to this photo to approximate the additional height.

Though it is huge, A23a is following the typical iceberg path to the South Atlantic. It floated in the Weddell Sea gyre, skirted the Antarctic Peninsula that points at South America, then was captured by the Antarctic Circumpolar Current that sends it toward South Georgia Island.

As it approaches South Georgia on 12 December 2024 you can see how huge it is compared to the island. Yow!

If A23a clogs the shore of South Georgia while it disintegrates, adult penguins and seals with young on the island will have to travel farther to get to food, which could cause their young to starve. This video explains what the iceberg is up to and how it could affect wildlife.

For an interactive view of the iceberg and its path, see the BBC article –> A23a: Tracking the world’s biggest iceberg as it drifts towards oblivion.