A large scale scientific project has confirmed fears that a major glacier in west-Antarctica is disappearing more quickly than previously thought because of warmer ocean waters.
The melting of the Thwaites Glacier, sometimes referred to as the Doomsday Glacier, which is the size of Great Britain, already accounts for four per cent of the rise in global sea levels.
Scientists from the UK and US are studying the glacier's changes as part of the International Thwaites Glacier Collaboration.
The BBC's chief environment correspondent Justin Rowlatt visited the project and observed what he described as "the chaos of broken ice at the front".
That broken ice spread almost 160km wide with hundreds of billions of tonnes of melt water is pouring into the sea.
Thwaites contains enough water to raise world sea levels by half a metre, with the west-Antartic ice sheet containing three metres more - enough to swamp many cities.
But scientists are mapping the ground beneath the glacier, which is located in one of the most remote places in the world. It is the stormiest part of the most stormy continent making work their difficult.
But University of Oregon's Kiya Riverman told the BBC, "If we're thinking about what is sea level going to be like in 10 years, this glacier is the place to be and this is the location to be asking these questions at."
It's taken huge resources and five weeks to get the scientists and their equipment to the front of the glacier.
Scientists for the first time drilled into the ice, but deploying instruments into the ice is the only way to make accurate predictions of how sea level will rise in the future.
This year's work has already confirmed their fears though - warm ocean water that circles Antarctica is flowing to the coast and because the seabed slopes downwards, as the ice melts it will expose increasingly more ice to that water, meaning the glacier could retreat increasingly rapidly.