Black carbon persists across the planet, accelerating glacial melt

June 30 (UPI) -- New research shows black carbon deposits vary across the planet, but persist in a variety of glacial ecosystems.

Black carbon is the soot-like particulate matter released by the combustion of fossil fuels, biofuel and biomass -- through man-made processes, like the burning of coal, and natural means, like wildfires.

Climate scientists are interested in black carbon because deposits among snow and glaciers affect melting rates. Black soot absorbs more energy than white snow and ice.

Scientists at the University of Colorado, Boulder recently conducted a global survey of black carbon deposits. Molecular analysis of the deposits helped scientists trace the sources of black carbon deposits and measure changes in deposition rates.

On Greenland's ice sheet, researchers found evidence of an uptick in black carbon. The sooty deposits were carried by winds from wildfires raging a few thousand miles away in the Canadian Arctic.

"We could tell that the carbon was fresh from these fires," Alia Khan, a post-doctoral researcher at Colorado's National Snow and Ice Data Center, said in a news release. "The molecular signature from these samples was distinctly different from the rest of our dataset."

If global warming encourages an uptick in the size and frequency of wildfires in the coming decades, as expected, the rise in black carbon deposits will likely accelerate glacial melt.

Researchers were able to detail how sun exposure alters the chemical structures in older black carbon deposits. They also showed glaciers, ice sheets and melted water can transport black carbon particles.

"The influence of distant forest fires on melt events on the Greenland ice sheet is inherently challenging to demonstrate and these clear chemical results provide another line of evidence for this connection," said Diane McKnight, a professor at Boulder.

Scientists published their findings in the journal Geophysical Research Letters.