Obama supports subsidies on corn-based ethanol. Why? Because Illinois is a corn-producer. So he says.
He also says he’s interested in contributing to climate change mitigation and adapation.
Dr Timothy Searchinger and colleagues (“Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change”, Science 29 February 2008, Vol. 319. no. 5867, pp. 1238 – 1240: http://www.sciencemag.org/cgi/content/abstract/1151861 ): “Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years.