The world’s largest iceberg just vanished after wandering the ocean for 40 years

The world’s largest iceberg has broken into tiny pieces and melted away. The last fragments of A23a are no longer visible in satellite images, bringing the story of one of Earth’s most extraordinary ice giants to a quiet close after nearly 40 years.

When A23a first broke away from Antarctica’s Filchner Ice Shelf in 1986, it covered around 3,500 square kilometres — bigger than Goa, roughly twice the size of London, and nearly three times the size of New York City. Its weight was estimated to be close to one trillion tonnes.

Soon after separating from the ice shelf, A23a got stuck on the seabed in the Weddell Sea and remained there for almost three decades, barely moving. It finally came loose in 2022 and drifted more than 2,300 kilometres through Antarctic waters into the South Atlantic, with satellites tracking almost every stage of its journey.

By March this year, the iceberg had shrunk to just 170 square kilometres, a tiny fraction of what it once was. In April, satellites captured one of its last images; soon after, there was nothing left big enough to spot from space.

Image: Wikimedia Commons/by NASA MODIS Land Rapid Response Team