The brighter the clouds, the cooler the planet?

Could the process of "brightening" clouds help curb the effects of global warming? Or would tinkering with the earth’s atmosphere lead to an even more frightening future?

From "cloud brighetening," where power plants suck carbon dioxide directly from the air, to spraying sulfur into the upper atmosphere, Popular Science's Jacob Ward explores the controversial world of geoengineering for an upcoming America Tonight special report.