Surprising strategy to fight global warming: Cut down on soot

A quick hit way to slow the pace of global warming may be to tackle soot emissions from things such as diesel cars and coal-burning cookstoves, according to a new study that finds the black carbon these devices emit is the second-biggest contributor to global climate change.

All told, soot has about two-thirds the effect on warming as the best-known greenhouse gas, carbon dioxide. The findings push methane, which is emitted by everything from belching cattle to fracking operations, from the No. 2 spot.