The black stuff

摘要

If carbon dioxide is the bete noire of climate change, how do we feel about the really black stuff, black carbon? We're pretty much in the dark, say some in the environmental movement who would like to see more notice taken of it. Black carbon is particulate matter that gets put into the atmosphere: it's basically soot, and some of it is in large particle form and some is very small indeed. What it does, says Kathye Henderson, marketing manager at the particulate filter manufacturer Eminox, is a two-part effect. "When it's in the atmosphere, it absorbs solar radiation and that has the effect of warming the atmosphere," she says. "And then when it settles, particularly if it falls on snow or ice, it reduces the reflectivity of the white surfaces and therefore they absorb more heat and melt more quickly. This last part is generally known as the albedo effect."