The Thwaites Glacier is one of five recently identified unstable Antarctic glaciers which have doubled their rate of ice loss in just six years. The glacial melting risks crossing a tipping point where it could cause an unstoppable 50cm rise in global sea levels, warns new research.
The Nasa-funded study claims the Thwaites Glacier is heading towards an ‘instability’ which could see the entire icy contents float out into the sea within 150 years. This means that there will probably come a point when it was impossible to stop it flowing into the sea. Other Antarctic glaciers are likely to be similarly unstable.
Study leader Dr Alex Robel, Assistant Professor in Georgia Institute of Technology’s School of Earth and Atmospheric Sciences, said: “If you trigger this instability, you don’t need to continue to force the ice sheet by cranking up temperatures.
“It will keep going by itself, and that’s the worry.
“Climate variations will still be important after that tipping point because they will determine how fast the ice will move.”
The Thwaites glacier, part of the West Antarctic ice sheet, is believed to pose the greatest risk for rapid future sea level rise.
Nasa scientist Helene Seroussi added: “After reaching the tipping point, Thwaites Glacier could lose all of its ice in a period of 150 years. That would make for a sea level rise of about half a metre (1.64 feet).”
The researchers found a precise estimate of how much ice the glacier would shed in the next 50 to 800 years was not possible due to unpredictable climate fluctuations and data limitations. However, 500 simulations of different scenarios pointed to it losing stability. This increased uncertainty about future sea level rise but made the worst-case scenarios more likely.
According to the Guardian, Antarctic sea ice had been gradually increasing during 40 years of measurement and reached a record maximum in 2014, before falling markedly.