claim: Barack Obama and Joe Biden will establish a 10 percent federal Renewable Portfolio Standard (RPS) to require that 10 percent of electricity consumed in the U.S. is derived from clean, sustainable energy sources, like solar, wind and geothermal by 2012.
evidence: IPCC AR4 WG1 Ch9 2007, p. 690: "Recent estimates indicate a relatively small combined effect of natural forcings on the global mean temperature evolution of the second half of the 20th century, with a small net cooling from the combined effects of solar and volcanic forcings."