Warming oceans are causing Antarctica’s ice sheet to melt from underneath, according to a new study. The results suggest climate change is having a bigger impact on ice loss in Antarctica than was previously thought.
Researchers found that between 2010 and 2016, warmer ocean temperatures caused Antarctica’s underwater ice to shrink by 1,463 square kilometres, an area as large as Greater London. The research was led by the UK Centre for Polar Observation and Modelling (CPOM) at the University of Leeds and was published on Monday in Nature Geoscience.
The study produced the first complete map of Antarctica’s underwater ice sheet and tripled the coverage of previous surveys. By combining satellite data with measurements of Antarctica’s “grounding line,” or the bottom edge of submarine ice, researchers were able to determine how much of Antarctica’s underwater ice is melting.
The largest declines in ice thickness were found in west Antarctica, More than a fifth of the ice sheet in this area has retreated on the sea floor at a faster rate than deglaciation above.
“Our study provides clear evidence that retreat is happening across the ice sheet due to ocean melting at its base, and not just at the few spots that have been mapped before now,” said Dr Hannes Konrad, a research fellow at the University of Leeds who led the research.
Dr Konrad warned of the effects this has on other areas. “This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise.”
“What’s happening is that Antarctica is being melted away at its base. We can’t see it, because it’s happening below the sea surface,” study co-author Professor Andrew Shepherd told The Guardian.
“The changes mean that very soon the sea-level contribution from Antarctica could outstrip that from Greenland,” Shepherd said, adding that the findings “should give people more cause for concern.”
A recent study led by scientists at Dartmouth College in New Hampshire found that the West Greenland Ice Sheet is melting at a faster rate than at any point over the last 450 years. Greenland’s ice loss currently contributes a millimetre to sea-level rise each year.
The Antarctica study’s findings are likely to spur an increase in global sea-level rise estimates, according to The Guardian. Previous projections were based on data from Thwaites Glacier and Pine Island Glacier in the West. In light of the new research, such measurements do not provide an accurate picture of the net ice melt that is occurring across the ice sheet.
Professor Shepherd underscored the role satellite technology played in tracking the movements of Antarctica’s grounding lines to provide the new insights, and highlighted the technology’s potential for future environmental research.
“They are impossible places to access from below, and usually invisible on the ground, so it’s a fantastic illustration of the value of satellite measurements for identifying and understanding environmental change,” he said.