New data released by climate scientists shows that Greenland’s ice sheet is melting faster than ever, predicting a greater sea level rise than previously thought.
The study, published on Jan. 4 in the scientific journal Nature-Climate Change, found that Greenland’s permanent ice sheet, which is between 1.5 and 2 kilometers (1.2 miles) thick at its deepest points, is losing 8,000 tons of mass each second, according to Radio Canada International. This marks a 30 percent increase in water loss over previous estimates, according to glaciologist William Colgan, an assistant professor at York University’s Lassonde School of Engineering in Toronto.
The changes that have resulted from the melting of the ice sheet have been dramatic, Colgan observed.
“[I would] see no rivers one year, and the next... [I saw] rivers extending ten or twenty kilometers inland and in places they had never been seen before,” Colgan said.
The changes in Greenland’s ice sheet have come about as the result of a natural phenomenon previously overlooked by scientists. Snow that falls onto the ice sheet creates a compacted layer of new ice, known as “firn." Traditionally, researchers believed that during periods of surface melting, water would sink down through the snow and be absorbed as ice by the firn layer.
However, the Jan. 4 study - which was conducted jointly by York University, the Geological Survey of Denmark and Greenland and the University of Colorado at Boulder in 2012, 2013 and 2015 - found that instead of forming ice as part of the firn, melting water would sink through the snow and bounce off of a solid ice layer formed during an extreme melt in 2012. This means that instead of re-forming, Greenland’s ice sheet is losing water at an unprecedented rate.
According to Colgan, this process is most likely occurring in other areas of the Arctic as well. Researchers studying rising sea levels will have to incorporate the new data into their studies going forward.