WASHINGTON - Antarctica is melting at an astonishing pace, losing three trillion tons of ice since 1992, a global team of scientists has concluded in a new assessment of the effects of global warming on Earth's southernmost continent.
The scientists said that between 1992 and 2011, Antarctica lost 76 billion (metric) tons of ice annually. They said the melting had increased to 219 billion (metric) tons a year as of 2012.
One of the study's 88 co-authors, the University of California Irvine's Isabella Velicogna, said, "I think we should be worried. That doesn't mean we should be desperate. Things are happening. They are happening faster than we expected."
Lead author Andrew Shepherd of the University of Leeds in England said it is possible that Antarctica's melting alone could add 16 centimeters to sea level rise across the globe by the end of this century.
"Under natural conditions, we don't expect the ice sheet to lose ice at all," Shepherd said. "There are no other plausible signals to be driving this other than climate change."
Shepherd said the melting is mostly caused by warmer waters. He said the southern ocean is affected by shifting winds, which are connected to global warming from the burning of coal, oil and natural gas.
Co-author Ian Joughin of the University of Washington said part of West Antarctica, where 70 percent of the recent melt has occurred, "is in a state of collapse."
A U.S. space agency scientist, co-lead author Eric Rignot, said, "We now have an unequivocal picture of what's happening in Antarctica. We view these results as another ringing alarm for action to slow the warming of our planet."
The scientists drew their conclusions from two decades of satellite data, 24 separate space-based surveys to track the loss of Antarctica's ice.
The study was published Wednesday in the journal Nature.