The most nauseating moment of spring: when black gunk from car tailpipes forms a crispy crust atop snow melting beside the road.

As it turns out, that soot from vehicle exhaust doesn't just foul the snow -- it plays an active role in melting the snow.  Black particles absorb the sun's heat, acting like tiny radiators that melt the ice.

The same phenomenon is happening on a massive scale at the earth's poles.  And the role of sooty air pollution in melting the world's ice, and driving up sea levels in the Chesapeake Bay and elsewhere, turns out to be much greater than the role of carbon dioxide, according to a new article in Scientific American, which draws upon a study published by University of California, Irvine, climate physicist Charlie Zender in the Journal of Geophysical Research.

Here's a link to the article: http://www.sciam.com/article.cfm?articleID=0BB80100-E7F2-99DF-3243FADB64A2D768&chanID=sa003 

"Black carbon in snow causes about three times the temperature change as carbon dioxide in the atmosphere," Zender says in the article.

Although forest fires contribute to the soot, at least 80 percent of it comes from human industry -- smokestacks of power plants, tailpipes of cars and trucks, and the exhaust vents of trains and ships.

This last factor -- pollution from ships -- creates a feedback loop.  As polar ice melts, more ships can make the once-impossible voyage over the top of Canada and Russia.  And their sooty exhaust dirties the snow around them, making it melt even faster.

The impact here in Maryland is obvious. Low lying sections of the Eastern Shore, like Hooper's Island, are being steadily eroded by rising water levels caused in part by the melting of the Greenland ice cap and glaciers.  

In a more immediate context, microscopic soot from coal-burning power plants also causes an estimated 30,000 deaths a year in the U.S. from heart attacks and asthma hospitalizations. Baltimore has one of the worst asthma hospitalization rates in America.

All this suggests that shifting away from coal as a source of power could potentially achieve two goods.  It could save our lungs, and it could clean up the snow.  And whiter snow could slow the flooding of Maryland's Eastern Shore and Baltimore's Inner Harbor, among other waterfront areas.