White Roof Alliance. The simple explanation is this: much of the worlds industrial (and personal) roofing is black as are our roadways. Black surfaces trap heat, warm up, and create heat islands. And it's not only black roofs! So the idea is to change the color of our rooftops and road surfaces and thereby cool things down. Of course they explain it much better than I do, along with the science, but it makes a lot of sense me thinks.
According to the site permanently changing the worlds rooftops would have the same effect as cutting out a full year of man made CO2 (in decreased cooling and heating costs). Cool.
Check it out.