President Bush promised to expand American biofuel production but the result seems to be causing more harm than good. Some believe that corn is a poor source for energy - growing it and other staples as fuel has caused food prices worldwide to explode, even as the scarcity of flex-fuel vehicles means no significant increase in U.S. biofuel use. Now the U.N. is worried about rising food costs, while environmentalists see entire regions torn up to grow fuel crops. The great ethanol boom of 2007 goes bust, this week on Global Pulse. SOURCES: Once Noticias, Latinoamerica News, Mexico; BBC, U.K.; Fox News, NBC News, ABC News, U.S.