GLACIERS are melting six times faster today than they were in the 1970s, prompting scientists to warn sea-level rise could be far faster than the already catastrophic projections.
New research from the University of California at Irvine (UCI) and NASA found the Antarctic lost 40 billion tonnes of melting ice to the ocean each year from 1979 to 1989. That figure rose to 252 billion tonnes lost per year from 2009 through 2017.
The scientists combined 40 years of satellite images and climate modelling and found the East Antarctic Ice Sheet – considered largely insulated from the ravages of climate change – may also be melting at an accelerating rate.
It takes 360 billion tons of ice to produce one millimetre of global sea-level rise. In total the melting of the Antarctic ice sheet has caused global sea levels to rise by at least 13.8 millimetres over the past 40 years.
If the results from the latest study, published Monday in the Proceedings of the National Academy of Sciences, are correct, the additional ice melt could dramatically alter current projections for sea level rise.
Climate scientist Michael Oppenheimer of Princeton University, told Science magazine it “changes the ball game for sea level rise in this century.”
Professor Eric Rignot, lead author and chair of Earth system science at UCI, said they were surprised to find the melting they detected was far more significant than scientists originally believed, especially in the East Antarctica sheet – the largest ice sheet on the planet.
“I don’t want to be alarmist,” Rignot told The Washington Post. “The places undergoing changes in Antarctica are not limited to just a couple places. They seem to be more extensive than what we thought. That, to me, seems to be reason for concern.”
A 2018 report from the UN Intergovernmental Panel on Climate Change warned the world could expect to see sea level rises of up to three feet by 2100 if our current carbon output continues unabated. This new data from the Antarctic could push that even further.
The destruction from just a couple of feet would be devastating. Island nations will disappear under water, millions of people will be displaced from their homes causing severe climate migration, habitats will be destroyed, and drinking water supplies will be threatened.
All of the ice of Antarctica holds the capacity for 57.2 metres of sea-level rise.
While the West Antarctic Ice Sheet has long been known to be losing ice, the colder temperatures and with a base mostly above sea level, scientist believed the East sheet would be immune to global changes.
But a shift in wind patterns around Antarctica, induced by climate change, has led some to believe warm water carried by a circular current off the continental shelf has started invading the ice.
The team compared the buildup of snow on the Antarctic Ice Sheet with the amount of ice that glaciers slough off into the Southern Ocean between 1979 and 2017 using aerial photographs, radar measurements taken from space and Landsat satellite imagery.
The study showed, rather than minimal contribution to ice melt, the East Ice Sheet actually, particularly the area known as Wilkes Land, was responsible for more than 30 percent of Antarctica’s contribution to sea level rise.
“This region is probably more sensitive to climate [change] than has traditionally been assumed,” Rignot said in a statement.
“As climate warming and ozone depletion send more ocean heat toward those sectors, they will continue to contribute to sea level rise from Antarctica in decades to come.”