Greenland will contribute almost a foot to sea level rise

The Greenland ice sheet is set to lose more than three percent of its mass, which will cause nearly a foot of sea-level rise, according to a study published today in the journal Nature Climate Change. The experts report that 3.3 percent of the ice sheet – the equivalent 110 trillion tons of ice – is now doomed. 

Study co-author William Colgan is a glaciologist at the Geological Survey of Denmark and Greenland. He explained that the culprit is “zombie ice,” which is no longer being fed by larger glaciers.

“It’s dead ice. It’s just going to melt and disappear from the ice sheet,” Colgan said in an interview. “This ice has been consigned to the ocean, regardless of what climate (emissions) scenario we take now.”

For the investigation, study lead author Professor Jason Box collaborated with scientists in Belgium, Denmark, Finland, Norway, the Netherlands, Switzerland and the United States. The experts set out to predict the minimum volume of ice that will be lost from the Greenland ice sheet as human-driven climate change continues.

The team estimated an inevitable loss of ten inches, or 27 centimeters, from zombie ice alone. This is more than double the amount of sea level rise that has been previously predicted from the melting of the Greenland ice sheet. Furthermore, Professor Box emphasized that the latest estimate is actually quite conservative. 

“It is a very conservative rock-bottom minimum. Realistically, we will see this figure more than double within this century,” said Professor Box. “In the foreseeable scenario that global warming will only continue, the contribution of the Greenland Ice Sheet to sea level rise will only continue increasing. 

“When we take the extreme melt year 2012 and take it as a hypothetical average constant climate later this century, the committed mass loss from the Greenland Ice Sheet more than doubles to 78 cm.”

The research is unique in that it has produced a minimum figure for Greenland ice loss based on two decades worth of actual measurements, rather than depending on highly uncertain computer models.

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By Chrissy Sexton, Earth.com Staff Writer