Environment: In 2005, America used 15% of its corn crop to replace just 2% of its gasoline. Two new studies say use of biofuels will leave the world a warmer and hungrier place.The law of unintended consequences has reared its ugly head once again, with a study published in the Feb. 7 issue of the journal Science. According to University of Minnesota ecologist and study co-author David Tilman, converting the grasslands of the U.S. to corn for ethanol releases excess CO2 emissions of 134 metric tons per hectare (equal to 2.47 acres). The reason is that plants, from grasses to...