Doomsday Glacier

Thwaites Glacier, in West Antarctica, is roughly the size of Florida. This glacier alone contributes four percent of the global rise in sea levels, and if it melted completely oceans would be 65cm higher – hence its alternative name, the Doomsday Glacier.

Thwaites Glacier from space
NASA, Public domain, via Wikimedia Commons

Most of the world’s fresh water is locked up in Antarctic ice. By volume, East Antarctica is the giant: if it melted, the oceans would be fifty metres higher (!) than they are now. But by risk, West Antarctica is the immediate threat: it’s warmer, less stable, and the glaciers here are calving off huge amounts of water right now.

The key to West Antarctica is Thwaites Glacier. It’s huge, close to the size of Florida or Great Britain. If it were an island, it would be the 11th largest island in the world (bigger than Java, Newfoundland, or Cuba). It’s the widest glacier in the world. And it’s melting.

In East Antarctica, ice shelves sit between the glaciers and the ocean. These ice shelves protect the glaciers from the worst of the ocean’s attacks. West Antartica lacks those ice shelves. The pointy edge of Thwaites Glacier, the Thwaites Ice Tongue pictured above, extends right out into the Amundsen Sea. And the warm water currents from that sea are undercutting it.

The water flows under the iceberg, carving out an underwater cavern. This flow loosens the grip of the iceberg on the underlying rock and accelerates its slide towards the sea. At the moment, fifty billion tons of ice is lost from Thwaites Glacier every year. Thwaites Glacier is the perfect storm of climate change risk. It’s huge, it’s vulnerable, and it’s changing more than any other glacier in Antarctica. Scientists call it the Doomsday Glacier. If/when sea levels rise catastrophically, this glacier will be the one to watch/blame.

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