Greenland ice loss less than forecast


RISES IN sea levels are unlikely to be as high as worst-case scenarios have forecast, according to research that shows Greenland’s glaciers are slipping into the sea more slowly than previously thought.

But the scientists warned that ice loss had still sped up by 30 per cent over the past decade and was driving rises in sea levels that endanger low-lying coasts.

Along with Antarctica, the loss of ice from the huge Greenland ice cap is the biggest direct contributor to rising sea levels, pouring 250 billion tonnes of water into the oceans each year. But the complexity of glacier dynamics has meant that predictions of future losses as global warming continues have been wide-ranging and controversial.

The new research used satellite data for the first time to track the progress of more than 200 Greenland glaciers between 2000 and 2010. “Previous studies only had a couple of observations from big glaciers,” said Twila Moon of the University of Washington in Seattle, who led the research.

“We found we are certainly not on the worst-case scenario, but the glaciers are speeding up and we see no sign of that stopping.”

Half of the ice lost from Greenland is due to simple melting, where water flows into the sea as temperatures rise, while the other half is due to the increased flow of glaciers, which leads to more icebergs caving into the sea.

The new study, published in the journal Science, focused on the latter effect.

Other recent satellite science has revealed complexities in other parts of the world, with the world’s greatest peaks in the Himalayan mountain chain revealed as having lost no ice in the past decade. Another study showed the Karakoram glaciers as having grown during the same period.

However, the contribution to sea level rise of these and other mountain chains such as the Andes and Alps are dwarfed by Greenland and Antarctica. – (Guardian service)