interesting article from sciam.com: A Deep Thaw: How Much Will Vanishing Glaciers Raise Sea Levels?
Greenland, the world's largest island, holds enough ice to raise global sea levels by 23 feet (seven meters). Add the ice sheets of Antarctica and the oceans would deepen more than 200 feet (60 meters). Satellite measurements from space and speed measurements on land confirm that Greenland's glaciers are melting and on the move. And although the picture is less clear in Antarctica, the global warming seems to be having an impact there, too.
So the question is: How muchand how soonwill sea level rise?
New research from glaciologist Tad Pfeffer of the University of Colorado at Boulder and colleagues published in Science attempts to better estimate the possible sea level rise over the next century by measuring the speed at which the world's glaciersin Greenland and Antarctica but also the many mountain ice sheets throughout the globeare actually speeding to the sea as well as how swiftly they may melt.
"What would the flow velocities of the ocean-ending outlet glaciers have to be," if Greenland alone was to raise sea level by just six feet (two meters)? "The answer turned out to be huge: about 49 kilometers [30 miles] per year, 70 times faster than those glaciers move today," Pfeffer says, "and three times faster than we've ever observed an outlet glacier to move."