Rising temperatures combined with ash from forest in the Northern Hemisphere could be the cause of the accelerated melting of the Greenland ice sheet.
This process could cause annual melting of the ice sheet's surface by the year 2100, a National Science Foundation news release reported.
Melting in the dry snow of the region does not cause sea level rise, but it moves into the snowpack and refreezes; this process can cause less light to be reflected, potentially leading towards even more melting.
"Forest fires burning far from Greenland provided the ash that, along with the warm temperatures, caused widespread melting of the Greenland Ice Sheet," Kaitlin Keegan, the lead author of the paper, said in the news release.
"It required the combination of both of these effects--lowered snow albedo from ash and unusually warm temperatures--to push the ice sheet over the threshold," Keegan said. "With both the frequency of forest fires and warmer temperatures predicted to increase with climate change, widespread melt events are likely to happen much more frequently in the future."
The presence of this ash along with ammonium indicate the source of the substances were in Siberia and North America between June and July of 2012.
The Greenland ice sheet usually melts along the coastline in July, but surface melting is rare during this time; in 2012 more than 97 percent of the ice sheet experienced melting. Analysis of ice cores showed the last time such as widespread melt occurred was in 1889.
"Our Earth is a system of systems; improved understanding of the complexity of the linkages and feedbacks, as in this paper, is one challenge facing the next generation of engineers and scientists--people like Kaitlin," Mary Albert, director of the NSF-supported Ice Drilling Program Office at the Thayer School of Engineering and Keegan's doctoral adviser, said in the news release.
