2012 Greenland Ice Melt Strongest On Record, More to Come

New data shows that melting of the vast ice sheet that covers more than three-quarters of Greenland is the strongest ever seen -- and there are still four weeks to go in the melting season.

Marco Tedesco, a researcher at the City College of New York, says the melting that scientists have observed in 2012 has already outstripped the melt in 2010. The melting season typically lasts from June to early September.

"With more yet to come in August, this year's overall melting will fall way above the old records," Tedesco said in a statement Monday.

"That's a goliath year, the greatest melt since satellite recording began in 1979."

This latest observation has not yet been published in a peer-reviewed journal, but Tedesco and his colleagues have a forthcoming paper looking at models projecting gains and losses to the ice sheet throughout the rest of this century.

NASA announced in July that its Earth Observation satellites (Modis, Aqua, Terra) had found that about 97 percent of the ice sheet's 660,000 square-mile surface had undergone melting.

This latest data from Tedesco and his colleagues jives with that finding. They used data from microwave satellite sensors in order to calculate the cumulative melting index, which gauges the "strength" of the melting season.

The index is generated by multiplying the number of days the ice sheet has melted by the total area of the ice sheet that has melted.

Rutgers University in Greenland

Åsa Rennermalm, a Rutgers University Hydrologist and researcher unaffiliated with the current project, studies the streams and rivers both on the ice sheet and those that are fed by meltwater.

She says the residents of Kangerlussauq, a town near her research site, confirm that this season's melt is the biggest they remember.

Kangerlussauq, which contains Greenland's major airport, was directly impacted by the higher melt on July 11, when a major bridge was destroyed by rising river, fed by melt-water.

"It was pretty dramatic," Rennermalm said.

Byrd Polar Research centre

Tedesco's colleague Jason Box, a researcher at Ohio State University's Byrd Polar Research Center, says there's a positive feedback mechanism at play in the ice sheet's melting; as the surface melts, it gets darker, which absorbs more heat from the sun.

In a downward spiraling action, the melted surfaces absorb more heat and this encourages further melting.