Black carbon from burning woodland magnifies melting caused by global warming
Billows of black carbon rising from forest fires in the Northern Hemisphere can swaddle the snow on Greenland’s ice sheet and hasten the frozen country’s melt.
Similar to asphalt radiating the sun’s heat, the dark particles of carbon can raise the surface temperature of snow, which relies on reflective powers to stay cold. Thus black carbon, part of the soot formed in wildfires, could speed the ice sheet’s thaw by melting snow atop the ice sheet, a new study suggests. That resulting meltwater then trickles into the ice sheet’s frozen core.
The study, led by Kaitlin Keegan of Dartmouth College, examined climate data and cores of Greenland’s snowy layers during the country’s biggest recorded thaws, in 1889 and 2012. The researchers found that those years experienced relatively warm temperatures as well as heavy blankets of black carbon, which combined to cause rare snow-surface melting on up to 97 percent of the ice sheet. The findings appear May 19 in the Proceedings of the National Academy of Sciences.
Climate change, fueled by greenhouse gas emissions, continues to warm the globe and provoke more and bigger wild fires. Using simulations of future climate conditions, the researchers predict that by 2100 Greenland will face extensive snowmelts every year.
K. M. Keegan et al. Climate change and forest fires synergistically drive widespread melt events of the Greenland ice sheet. Proceedings of the National Academy of Sciences. Published online May 19, 2014. doi:10.1073/pnas.1405397111.
B. Mole. Glacial microbes gobble methane. Science News Online, April 25, 2014.