A glacier larger than Spain could raise sea levels dramatically after scientists found more of it is floating than previously thought.
Antarctica’s Totten Glacier could increase sea levels by about three metres (9.8ft) if it all melted, scientists from the Australian Antarctic Division warned.
After spending the southern hemisphere’s summer on the glacier, scientists discovered more of the ice is floating on the ocean than initially thought.
Totten is one of the fastest-flowing and largest glaciers in Antarctica so scientists wanted to keep an eye on how fast it is melting due to the massive amounts of water it could unleash.
Using artificially created seismic waves to see through the ice, researchers found parts which they thought were on solid ground were actually floating on ice, meaning they risk melting faster.
Recent research had already found Totten’s underbelly was being eroded by warm, salty sea water flowing hundreds of miles inland through underwater gateways.
“In some locations we thought were grounded, we detected the ocean below indicating that the glacier is in fact floating,” said Paul Winberry from Central Washington University, who spent the summer studying the glacier.
He said the discovery could help explain recent periods of accelerated melting.
“It also means the Totten might be more sensitive to climate variations in the future,” he added.
Glaciers hold most of the Earth’s fresh water and as they move down valleys, mountains and slopes over many centuries they melt into the water causing sea levels to rise.
Between 2002 and 2016, Antarctica lost 125 gigatonnes of ice annually, causing global sea levels to rise by 0.35mm a year, NASA found.
Ben Galton-Fenzi, from the Australian Antarctic Division, said: “Since the 1900s the global sea level has risen by around 20cm and by the end of the century it’s projected to rise by up to one metre or more, but this is subject to high uncertainty which is why studying glaciers such as the Totten is important.
“These precise measurements of Totten Glacier are vital to monitoring changes and understanding them in the context of natural variations, and the research is an important step in assessing the potential impact on sea-level under various future scenarios.”
The team has left instruments on the glacier to measure flow, speed and thickness over the next 12 months.