Biofuels may boost pollution

The process of turning coal into liquid (liquefaction by hydrogenation) actually produces nearly double the level of carbon dioxide emissions that conventional gasoline does, and it is considered by many environmentalists as a huge step backward for combating global warming. Other popular alternative fuels, such as corn ethanol, can also be more polluting. Whether corn ethanol is more or less polluting than gasoline will depend on how it the cord is grown, the study reports, and how the ethanol is produced.