Mercy! One-third. That's a lot.
A team of U.S. scientists has found that "dirty snow" is a surprisingly significant contributor to global warming, and is urging Canada - as "custodian" of a vast, snowbound nation - to lead an international cleanup effort.
The researchers have measured, in the first comprehensive study of its kind, how snowy landscapes tainted by carbon particles from inefficiently burned fuels and forest fires are absorbing more of the sun's heat than the less sooty snow cover of centuries past.
"Snow becomes dirty when soot from tailpipes, smokestacks and forest fires enters the atmosphere and falls to the ground," the team explains. "Soot-infused snow is darker than natural snow. Dark surfaces absorb sunlight and cause warming, while bright surfaces reflect heat back into space and cause cooling."
Even a slightly darkened surface impairs the natural reflective properties of snow crystals, say the scientists, who calculated that dirty snow accounts for one-third of rising temperatures in the Arctic over the past two centuries.
Monday, June 11, 2007
The problem with dirty snow
It's always something, isn't it? Here's one more example of how our behavior causes global warming. It's from an article entitled "'Dirty snow' warming Earth, study finds":