Greenland Ice to Contribute Far More to Sea Level Rise Than Previously Thought

Greenland's ice may be more susceptible to warming temperatures than we thought. Scientists have revealed that, because of Greenland's unique topography, its glaciers may retreat far faster and far further than initially thought.

Since the 1970s, researchers have only collected limited ice thickness data by using radar pinging off of the boundary between the ice and the bedrock in Greenland. Yet along the coastline, rough surface ice and pockets of water cluttered the radar sounded and effectively made large regions invisible. Yet thanks to NASA's Operation IceBridge flights, data has improved. Now, scientists have taken a step further in learning more about Greenland's ice sheet.

The researchers designed a novel "mass conservation algorithm" that combines the previous ice thickness measurements with information on the velocity and direction of the ice's movement and estimates of snowfall and surface melt. Using this information, the scientists found that what appeared to be shallow glaciers at the edges of Greenland are actually long, deep fingers that stretch inland.

"The glaciers of Greenland are likely to retreat faster and farther inland than anticipated-and for much longer-according to this very different topography we've discovered beneath the ice," said Mathieu Morlighem, one of the researchers, in a news release. "This has major implications, because the glacier melt will contribute much more to rising seas around the globe."

In fact, ice melt has already accelerated as warmer currents from the ocean have migrated northward. Now, it seems as if this melt will continue as seawater seeps into these finger-like trenches where the glaciers are located-even though researchers previously assumed that these glaciers would reach higher ground and ocean-induced melting would halt.

"We anticipate that these results will have a profound and transforming impact on computer models of ice sheet evolution in Greenland in a warming climate," stated the researchers in a news release.

The findings are published in the journal Nature Geoscience.