Change measurements (meters per yr) are median filtered (10-km radius), spatially averaged (5-km radius) and gridded to 3 km over the period 2003–2007

New satellite information shows that ice sheets in Greenland and western Antarctica continue to shrink faster than scientists thought and in some places are already in runaway melt mode.

British scientists for the first time calculated changes in the height of the vulnerable but massive ice sheets and found them especially worse at their edges. That’s where warmer water eats away from below. In some parts of Antarctica, ice sheets have been losing 30 feet a year in thickness since 2003, according to a paper published online Thursday in the journal Nature.

Some of those areas are about a mile thick, so they’ve still got plenty of ice to burn through. But the drop in thickness is speeding up. In parts of Antarctica, the yearly rate of thinning from 2003 to 2007 is 50 percent higher than it was from 1995 to 2003. (Read More @ Associated Press)

Pritchard HD, Arthern RJ, Vaughan DG, Edwards LA (2009) Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets. Nature doi:10.1038/nature08471