Study: Greenland glaciers moving slower than thought

New research looking into the speed at which Greenland’s glaciers are slipping into the ocean suggests that previously predicted rises in sea-levels are unlikely. The team from the University of Washington found that although Greenland’s ice loss has increased by 30 percent, the glaciers are not melting into the sea as quickly as many thought.

Due to the complexity of the way in which glaciers are formed and dissolved, previous predictions of melting and subsequent sea-level rises have been both controversial and contradictory. The new team is, however, the first to use satellite images to map the progress of 200 specific glaciers over a 10-year period.

“Previous studies only had a couple of observations from big glaciers,” Twila Moon, who led the research, said in a report by The Guardian. “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.”

Although much of Greenland’s ice loss is due to meltwater running into the sea as temperatures rise, the new study looked at how the increased flow of glaciers is causing more to break off. “We found, contrary to conventional wisdom, that glaciers have rapid and large changes in speed,” said Moon.

University of Bristol glaciologist Jonathan Bamber told the British newspaper that, “The study provides a lot of rich detail about the variability in ice sheet dynamics, but does not dramatically change our overall understanding. The new work shows the situation is not as bad as the worst possible case, but it is still serious for future sea level rise and is certainly more complex than many of the models suggest.”

Previous studies have suggested that the increasing speed of Greenland’s glaciers could raise global sea levels by between 80cms and two metres by 2100. However, the new research suggest that glacier acceleration is “well below” even the lowest estimates.

“Ten years is still a short time when studying glaciers. There is no reason to think we won’t get to the 80cm level. And even small rises in sea level will have very big impact in some places, as storm surges hit coasts. If you raise the floor of a basketball court by just a few inches, you will see many more slam dunks,” said Moon.