Scientists working at Mendenhall Glacier near Juneau -- historically far from the biggest sources of human-caused air pollution -- believe they are finding clues to the spread of carbon soot through the atmosphere during the Industrial Revolution. Red Orbit reports on new research in which carbon dating lets scientists link soot deposited on glaciers by snow and rain to the burning of fossil fuels and forests far away.
Globally, glacier ice loss is accelerating, driven in part by the deposition of carbon in the form of soot or "black carbon," which darkens glacier surfaces and increases their absorption of light and heat. The burning of biomass - trees, leaves and other vegetation around the globe, often in fires associated with deforestation - and fossil fuel combustion are the major sources of black carbon.
[Robert Spencer of the Woods Hole Research Center in Massachusetts] and his fellow scientists have conducted much of their research at the Mendenhall Glacier near Juneau. Mendenhall and other glaciers that end their journey in the Gulf of Alaska receive a high rate of precipitation, which exacerbates the deposition of soot, but also makes for a good research site.
"We are finding this human derived signature in a corner of the U.S. that is traditionally viewed as being exceptionally pristine," Spencer notes. "The burning of biomass and fossil fuels has an impact we can witness in these glacier systems although they are distant from industrial centers, and it highlights that the surface biogeochemical cycles of today are universally post-industrial in a way we do not fully appreciate."