The Antarctic ice sheet is losing 36 cubic miles of ice a year – equal to 264 billion gallons of water, enough to satisfy U.S. water consumption for three months, say two University of Colorado at Boulder researchers.
“For the first time, we can come up with a number and say the Antarctic ice sheet is losing significant mass and contributing to a rising sea level,” said CU’s Isabella Velicogna, principal author of the study, published Thursday in the online issue of Science Express.
Antarctica contains 70 percent of Earth’s fresh-water resources.
The study is the first to quantify the decline of the ice sheet – which is twice as large as Australia – due to global warming.
In the past, scientists have only been able to estimate changes in parts of the ice sheet.
The melting ice is equivalent to a four-tenths of a millimeter rise in global sea levels annually.
“I can’t tell you New York City will be underwater in so many years, but you want to keep track of it,” said John Wahr, a CU physics professor who was co-author of the study. “If glacial discharge into the ocean accelerates, sea level could rise faster.”
A Delaware-size block of ice that disintegrated into the ocean four years ago uncorked a flow of glaciers toward the ocean, Wahr said.
There’s enough ice in the Antarctic ice sheet to raise sea level a catastrophic 150 to 200 feet, he said.
The CU researchers used data from twin NASA satellites orbiting Earth in tandem to calculate the total ice mass in Antarctica from April 2002 to August 2005.
The study challenges the belief by scientists that snowfall on the interior of the ice sheet counters glacial loss on the edges, Wahr said.
The Intergovernmental Panel on Climate Change predicted in 2001 that the Antarctic ice sheet would increase in mass in the 21st century because of increased snowfall.
Staff writer Dave Curtin can be reached at 303-820-1276 or dcurtin@denverpost.com.
