The Winter Wonderland Could be a Thing of the Past

A NASA funded satellite study has revealed that ice sheets in Greenland and the Antarctic are melting three times faster than mountain glaciers and ice caps throughout the rest of the world. The research also suggested that climate change was contributing to rising sea levels at a much more rapid pace than forecasts are predicting.

Research compiled over almost 20 years has revealed that in 2006 the ice sheets in Greenland and the Antarctic lost a combined mass of 475 gigatonnes, which is enough to raise sea levels by half an inch. Ice sheets, which are defined as sheets of ice larger than 50,000 square kilometers and are only found in Greenland and the Antarctic and are said to be decreasing in size at an alarming rate.

Researchers found that over the 20 years, the ice sheets were losing an average mass of 36.3 gigatonnes each year, while ice caps had a comparable average yearly mass reduction that was three times smaller than that of ice sheets.

The study, which was led by Eric Rignot, of the University of California, Irvine and NASA’s Jet Propulsion Laboratory in Pasadena is due to be published in this month’s Geophysical Research Letters, which is a journal of the American Geophysical Union. "That ice sheets will dominate future sea level rise is not surprising. They hold a lot more ice mass than mountain glaciers. What is surprising is this increased contribution by the ice sheets is already happening. If present trends continue, sea level is likely to be significantly higher than levels projected by the United Nations Intergovernmental Panel on Climate Change in 2007. Our study helps reduce uncertainties in near-term projections of sea level rise," said Rignot, who is the lead author of the study.

The research team used almost two decades of NASA satellite measurement images with advanced models of atmospheric climate data to evaluate the speed at which the mass of ice sheets and ice caps were disappearing at.
During the research, the team used two different techniques to review the data. Interferometric synthetic aperture radar data was taken from European, Japanese and Canadian satellites in order to measure the ice sheets and climate atmospheric models were taken from the University of Utrecht. The second technique was used by gathering NASA data from Gravity Recovery and Climate Experiment satellites or GRACE satellites that tracked ice movements.

“These are two totally independent techniques, so it is a major achievement that the results agree so well. It demonstrates the tremendous progress that's being made in estimating how much ice the ice sheets are gaining and losing, and in analyzing Grace's time-variable gravity data." said Isabella Velicogna, the co-author, who also works with the University of California, Irvine and NASA’s Jet Propulsion Laboratory.

Photo Credit: Hgrobe