Soot Suspect in Mid-1800s Alps Glacier Retreat

Sep. 2, 2013 — Scientists have uncovered strong evidence that soot, or black carbon, sent into the air by a rapidly industrializing Europe, likely caused the abrupt retreat of mountain glaciers in the European Alps.
 
When black carbon particles settle on snow, they darken the surface. This melts the snow and exposes the underlying glacier ice to sunlight and relatively warm air earlier in the year, allowing more and faster melt.

To determine how much black carbon was in the atmosphere and the snow when the Alps glaciers began to retreat, the researchers studied ice cores drilled from high up on several European mountain glaciers. 

By measuring the levels of carbon particles trapped in the ice core layers and taking into consideration modern observations of the distribution of pollutants in the Alps, they could estimate how much black carbon was deposited on glacial surfaces at lower elevations, where levels of black carbon tend to be highest.

The team then ran computer models of glacier behavior, starting with recorded weather conditions and adding the impact of lower-elevation black carbon. By including this impact, the simulated glacier mass loss and timing finally were consistent with the historic record of glacial retreat, despite the cool temperatures of the time.

"This study uncovers some likely human fingerprints on our changing environment," Abdalati, Director of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder, said. "It's a reminder that the actions we take have far-reaching impacts on the environment in which we live."

http://www.sciencedaily.com/releases/2013/09/130902162752.htm