How an iceberg’s ‘final dance’ tells a story about our past and future
One of the biggest icebergs in recent memory is melting out of existence. Its silent fate mirrors the neglect of our biosphere

A23a was one of the largest “megabergs” to be spawned in our lifetimes. When it broke away from the Filchner Ice Shelf into the Weddell Sea in Western Antarctica in 1986, it covered an area of around 4,000 sq km – about the size of Hong Kong and Shenzhen combined.
In contrast to such stars, A23a has led a reclusive life, twisting and turning unnoticed across the South Atlantic. For its first 30 years, it was jammed in the Weddell Sea in Western Antarctica, a major source of the continent’s big icebergs. But then A23a was caught in “Iceberg Alley” and carried up to South Orkney. From there, it was roiled in a giant rotating vortex called the Taylor Column. It spun on the spot for eight months, but eventually broke north towards South Georgia, which is the graveyard for most of Antarctica’s icebergs.
