I've written a fair bit about black carbon, a form of soot created by incompletely burning biomass. Wood cookstoves in the developing world are one big culprit. The dark soot particles settle on snow and ice and absorb more sunlight; recent studies have found they contribute quite a bit to Arctic ice-melt and the wilting of Himalayan glaciers. All told, black carbon is estimated to be responsible for about 20 percent of current man-made global warming—behind only CO2, which currently accounts for about half.

The good news, though, is that the soot only lingers in the atmosphere for a few weeks (unlike CO2, which stays in the air for about 100 years on average), so there's an opportunity to make quick headway on climate change. That was the theme at a House hearing on the subject yesterday, at least. Veerabhadran Ramanathan, a climate expert at the Scripps Institute of Oceanography, told Congress: "Reducing black carbon emissions by fifty percent today will lead to a fifty percent reduction in the heat trapped by them within a few months."

Not bad. And the fixes are readily available: filters on diesel engines to capture soot, plus more efficient cook stoves for the developing world. What's largely needed are a few new diesel regulations in rich countries, plus some financing for soot-reduction projects abroad. (One expert pointed out that the EPA currently has the authority under the Clean Air Act to retrofit diesel engines in the United States, but the program doesn't have nearly enough funds to keep up with requests.) The climate payoff would be quick, and there'd be substantial health benefits too—soot pollution has been linked to rash of respiratory infections, and by some counts causes 7 percent of child deaths worldwide.

Indeed, mopping up black carbon such a no-brainer that not even conservatives really object. At the hearing, James Sensenbrenner, the committee's ranking Republican, agreed that both parties should support soot-removal. But he then went a step further and said we have a choice between tackling black carbon and tackling CO2, and we can only do one, so black carbon it is. Most of the scientists on the panel pointed out (politely) that Sensenbrenner's either-or view wasn't even remotely logical, and that both black carbon and CO2 needed to be addressed. Still, getting rid of black carbon is a smart short-term fix, and it's nice to see that that, at least, has support across the board.

(Flickr photo credit: Manny Pabla)