A new study (subscription required) in Science shows that the ice sheets of Greenland are melting at a fast and accelerating rate. This is yet another example of how the latest science is showing that the effects of climate change are moving faster than even the worst-case scenarios of the IPCC's 2007 consensus report.
The report, based on satellite observations, states that the Greenland ice sheet lost approximately 1500 gigatons of ice mass from 2000-2008. This is about 0.46 millimeters per year of global sea level rise. And, the rate of loss is increasing. Since 2006, high summer melt rates have increased Greenland ice sheet mass loss to 273 gigatons per year (0.75 millimeters per year of equivalent sea level rise).
Importantly, this article appears to resolve much of the uncertainty about how much the ice sheet is melting. The article used two independent methods, one based on observations and the other on remote gravity measurements made by satellites. By getting these two approaches to agree, we can get a clearer, more precise view of what is actually happening. I have said before that policymakers are asking for better science. Unfortunately, its not pretty.
Whether we can keep the Greenland ice sheet intact will be an important factor in keeping Bangladesh, the Maldives, or New York above rising sea levels. The water contained in these ice sheets could account for 7 meters of sea level rise.