The reputation of black carbon, aka the particles that make up soot, just got a whole lot dirtier, thanks to a four-year study of its impact on global warning. The analysis, compiled by 31 authors, found that black carbon's contribution to climate change is double what it was believed to have been, a finding that bumps it above methane as the second-biggest human factor in global warming. The Washington Post reports it is now second only to carbon dioxide, and has about two-thirds the impact of that gas.
Black carbon is emitted by things like diesel engines and wood-burning stoves, and exacts woe on the planet through its ability to absorb heat when airborne; it can also fall on snow and ice and darken it, thereby ramping up glacier melt. The US has made strides in cutting these emissions; the same can't be said for Southeast Asia and China. The study's authors assert that further cuts could provide an immediate boon, cutting temps by almost one degree Fahrenheit in the short-term. Doing so could give human health a boost, too, as the fine particles contribute to heart and respiratory problems. But carbon dioxide remains enemy No. 1: As the New York Times explains, it lingers in the atmosphere for decades; black carbon's lifespan is only about 10 days. (Read more global warming stories.)