Polar ice melt accelerating rapidly, raising sea level

A new study from University of California has suggested that the pace at which the Greenland and Antarctic ice sheets are melting is 'accelerating rapidly' and raising the global sea level.
 
The findings suggest that the ice sheets have become "the dominant contributor to global sea level rise, much sooner than model forecasts have predicted".
 
This study, the longest to date examining changes to polar ice sheet mass, combined two decades of monthly satellite measurements with regional atmospheric climate model data to study changes in mass.
 
"That ice sheets will dominate future sea level rise is not surprising - they hold a lot more ice mass than mountain glaciers," News.com.au quoted lead author Eric Rignot, jointly of NASA's Jet Propulsion Laboratory and the University of California, Irvine, as saying.
 
"What is surprising is this increased contribution by the ice sheets is already happening," he said.
 
Under the current trends, sea level is likely to be "significantly higher" than levels projected by the United Nations climate change panel in 2007, he said.
 
Isabella Velicogna, co-author of the study, said that the ice sheets lose mass by melting or by breaking apart in blocks of ice, which float into the ocean.
 
The study showed that in 2006, a year in which comparable results for loss from mountain glaciers and ice caps are available, the Greenland and Antarctic ice sheets lost enough mass to raise global sea level by an average of 1.3mm per year.
 
"The authors conclude that, if current ice sheet melting rates continue for the next four decades, their cumulative loss could raise sea level by 15cm by 2050," said the report.
 
The findings have been published in the Geophysical Research Letters.