New Data Show Ice Loss in Greenland Accelerating
Without an agreement that reduces climate changing emissions, coastal communities around the world are at risk of rising sea levels. New data confirm the Greenland ice sheet is losing mass at an accelerating rate. The calculations, based on state-of-the-art satellite observations combined with computer models of Greenland's changing icescape, are further evidence, scientists say, of the impact of global warming.
The calculations are considered the most reliable to date because they combine data from the twin Gravity Recovery and Climate Experiment satellites, known as GRACE, with computer models of Greenland's changing icescape. GRACE detects alterations in gravity caused by reductions in the ice sheet. But the calculations do not tell scientists what is causing the ice cap to shrink, says Michiel van den Broeke, a professor of polar meteorology at Utrecht University in the Netherlands. Van den Broeke and colleagues created a model he says indicates the formation of icebergs and melting ice play equal roles in reducing the size of the Greenland Ice Sheet.
The study by van den Broeke and colleagues traces the beginning of Greenland's ice loss to 1996. Some experts believe if current trends continue, global sea levels will rise by a meter or more by the end of the century. Steve Nerem, a professor of aerospace engineering sciences at the University of Colorado in Boulder says that is why it is important to refine predictions of what the Greenland Ice Sheet is going to do.
If the entire Greenland ice sheet were to melt, Nerem says it contains enough water to cause a global sea-level rise of seven meters. For low-lying countries to prepare, Nerem says, scientists need to know how quickly the Greenland ice mass is melting.
"If the meter in sea level rise were to happen very rapidly, say in 50 years, it will be very hard to build the infrastructure, you know the dykes – and the other things to hold back the water – quickly enough to prevent the inundation that would occur with a meter of sea-level rise. If it were to take hundreds of years, then that would probably be enough time for populated areas to build the protections that they need to combat this."
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