Greenland may lose ice more rapidly in future than previously thought

Washington: A new study has provided the first comprehensive picture of how Greenland's glaciers have changed over the past decade.

The research at the University at Buffalo suggests that current ice sheet modeling studies are too simplistic to accurately predict the future contributions of the entire Greenland Ice Sheet to sea level rise and that Greenland may lose ice more rapidly in the near future than previously thought.

The Greenland Ice Sheet, which is the second-largest body of ice on Earth, covers an area about five times the size of New York State and Kansas combined, and if it melts completely, oceans could rise by 20 feet. Coastal communities from Florida to Bangladesh would suffer extensive damage.

Researcher Cornelis J. van der Veen said that this information is crucial for developing and validating numerical models that predict how the ice sheet may change and contribute to global sea level over the next few hundred years

The study had two major findings, first, the scientists were able to provide new estimates of annual ice loss at high spatial resolution (see below) and second, the current models fail to accurately capture how the entire Greenland Ice Sheet is changing and contributing to rising oceans.

Today's simulations use the activity of four well-studied glaciers, Jakobshavn,Helheim, Kangerlussuaq and Petermann, to forecast how the entire ice sheet will dump ice into the oceans.

But the new research shows that activity at these four locations may not be representative of what is happening with glaciers across the ice sheet, in fact, glaciers undergo patterns of thinning and thickening that current climate change simulations fail to address, geophysicist Beata Csatho says.

Csatho added that there are 242 outlet glaciers wider than 1.5 km on the Greenland Ice Sheet, and what they see is that their behavior is complex in space and time. The local climate, geological conditions and the local hydrology, all of these factors have an effect. The current models do not address this complexity.

An analysis found that the Greenland Ice Sheet lost about 243 metric gigatons of ice annually from 2003-09, the period for which the team had the most comprehensive data. This loss is estimated to have added about 0.68 millimeters of water to the oceans annually.

The results will be published on Dec. 15 in the Proceedings of the National Academy of Sciences.