Thirty-two experts will spend more than two months on board an American research ship to explore the crucial area where the enormous, melting Thwaites Glacier meets the sea.

The Britain-sized glacier has earned the nickname the "doomsday glacier" because of the threat its melting would pose to the world, with the potential to raise sea levels eventually by more than two feet.

It is already shedding around 50 billion tons of ice into the water a year and the British Antarctic Survey says it is responsible for 4% of global sea rise.

Given its potential to profoundly impact all parts of the world, the US and the UK are in the midst of a joint £37m mission to study Thwaites, the widest glacier in the world by land and sea.

It lies east of Antarctica's peninsula, far from any of the continent's research stations.

"Thwaites is the main reason I would say that we have so large an uncertainty in the projections of future sea level rise and that is because it's a very remote area, difficult to reach," said Anna Wahlin, an oceanographer from the University of Gothenburg in Sweden.

Speaking from the Research Vessel Nathaniel B Palmer, which was scheduled to leave its port in Chile hours later, she added: "It is configured in a way so that it's potentially unstable. And that is why we are worried about this."

The glacier is particularly vulnerable to melt because it is being melted from beneath by warming ocean water, it is losing its grip on the area where it attaches to the seabed, and it is breaking into hundreds of fractures, with some as long as six miles.

Ms Wahlin's team will use two robot ships - her own large one called Ran which she used in 2019 and the more agile Boaty McBoatface, the crowdsource named drone that could go further under the area of Thwaites that protrudes over the ocean - to get under the glacier.

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