Wed Sep 23, 1:01 pm ET
WASHINGTON 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
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.
These new measurements, based on 50 million laser readings from a NASA
satellite, confirm what some of the more pessimistic scientists
thought: The melting along the crucial edges of the two major ice
sheets is accelerating and is in a self-feeding loop. The more the ice
melts, the more water surrounds and eats away at the remaining ice.