Avg. Global Annual Net Ice Loss - 385 Billion Tons - Filling Lake Erie Eight Times Over [View all]

[hatrack]

There isn’t a doubt in the world (among serious scientists, anyway) that the sea has been rising for the past century, by about eight inches in total since 1900. There’s little doubt, either, that the rise has been speeding up over the past couple of decades — the water has been inching up about as twice as fast lately as it was for most of the 20th century.

All of that is a powerful confirmation of what thermometers tell us: that the Earth is warming — the result, say those same serious scientists, of human-generated, heat-trapping greenhouse gases. That heat makes seawater expand, and it also transforms land-based ice into even more water that swells the oceans further.

What nobody has firmly pinned down so far, though, is just how big a contribution all that new water makes to the rising seas. They’ve come up with an estimate, by calculating how much should come from heat expansion then blaming the rest on melting ice: about 1.8 millimeters per year, says University of Colorado physicist John Wahr. But that’s not as convincing as a direct measurement, and it doesn’t solve the mystery of where all the ice is disappearing from.

Now, however, thanks to Wahr and three other scientists, the measurement question and the mystery have both been answered. Using a high-flying pair of satellites known collectively as GRACE, the Gravity Recovery and Climate Experiment mission, they’ve been watching carefully since 2002 to see, among other things, which of the planet’s glaciers and ice sheets are shrinking and by how much. The answer, just reported in Nature: between 2003 and 2010, about 385 billion tons of ice have vanished into the sea each year — enough, says Wahr, “to fill Lake Erie with water eight times over, or cover the entire U.S. with water to a depth of a foot and a half.”

EDIT

http://www.climatecentral.org/news/how-much-ice-is-vanishing-into-the-seas-you-dont-want-to-know/