A new study shows that pollution from automobiles and coal-fired power plants is contributing to the melting of mountain snowpacks up to a month early, exacerbating water shortages and polluting streams in the arid West.
We’ve all seen it. That white fluffy blanket of snow that looked so nice after it fell a couple weeks back is no longer white and fluffy. It has been capped with a layer of dark sooty particulate matter, turning it from white to gray to black. Having grown up in the Boston area, this was the reality of virtually every snowstorm I can recall from my youth. But that dark, sooty particulate matter that builds up on the stale snow is not only an aesthetically unpleasing feature of urban landscapes in the winter, it happens in the North American snowscapes of the Rockies, the Sierra Nevadas and the Cascades - with far more serious consequences.A peer-reviewed study conducted by scientists at the Department of Energy’s Pacific Northwest National Laboratory, is the first to explore changes to snowmelt caused by soot pollution at a regional level. The study, authored by Qian, Gustafson, Leung and Ghan, is scheduled to be published next month in the Journal of Geophysical Research-Atmospheres.
The study found that particulate emissions from automobile tailpipes and industry smokestacks settles on snow-covered mountains and covers them with a dark layer that absorbs more sunlight and melts the snow faster.
“Soot acts like tiny toaster ovens in the snowpack, and when the sun hits them, they heat up and melt the snow,” said Charles Zender in an article at Energy & Environment (Sub$cription req’d.), an atmospheric physicist at the University of
In a previous paper about the effects of dust layers on snowmelt, researchers found that dust affecting the San Juan Mountains snowpack originated in the
The implications of the study’s findings range from ecological to economic and political.
The expedited rate of snowmelt makes those dry summers of the American West that much tougher to stomach without rainfall. And because concentrations of the particulate matter are so high in the summer months the effects on water quality could have devastating ecological impacts.
So, not only is there less water in summer months, the water that is available will have higher concentrations of dirt, ash and soot from as far away as China.“The important thing is the change in timing of available water,” explained William Gustafson, an atmospheric scientist at the Pacific Northwest National Laboratory and one of the study’s primary authors. In essence, there will be plenty of water in the early spring, when water availability is never a problem. But come late summer, rivers are losing their water much earlier than before.
But faster runoff also means less water for farming and residential use, less potential for hydroelectric energy, shorter rafting and skiing seasons and less-than stellar fishing conditions. For Rocky Mountain states like