Antarctica is losing six times more ice than it did 40 years ago, a new study shows.
Scientists have used aerial photographs, satellite measurements and computer models to track how fast the sourthern-most continent has been melting since 1979 in 176 individual basins.
They found the ice is melting six times faster than it did in the 1980s.
They found that the dramatic acceleration is a key indicator of human-caused climate change.
The study also revealed that since 2009, Antarctica has lost almost 252 metric tons of ice a year.
In the 1980s, it was losing 40 billion metric tons a year.
The recent melting rate is 15 percent higher than what a study found last year.
Eric Rignot, a University of California, Irvine, ice scientist, was the lead author on the new study in Monday's Proceedings of the National Academy of Sciences.
He said the big difference is that his satellite-based study found East Antarctica, which used to be considered stable, is losing 51 billion metric tons of ice a year.
Last year's study, which took several teams' work into consideration, found little to no loss in East Antarctica recently and gains in the past.
Melting in West Antarctica and the Antarctica Peninsula account for about four-fifths of the ice loss.
East Antarctica's melting "increases the risk of multiple metre (more than 10 feet) sea level rise over the next century or so," Rignot said.
Richard Alley, a Pennsylvania State University scientist not involved in Rignot's study, called it "really good science."
