the amount of grain needed to make enough ethanol to fill a 25-gallon SUV tank "would feed one person for a full year. If the United States converted its entire grain harvest into ethanol, it would satisfy less than 16 percent of its automotive needs." Brown said the ongoing ethanol boom in the U.S. was "setting the stage for an epic competition. In a narrow sense, it is one between the world's supermarkets and its service stations." More broadly, "it is a battle between the world's 800 million automobile owners, who want to maintain their mobility, and the world's 2 billion poorest people, who simply want to survive."

Avery says that even if the U.S. adopted biofuels as the antidote for imported crude oil, "It would take more than 546 million acres of U.S. farmland to replace all of our current gasoline use with corn ethanol."

That's a huge area, especially considering that the total amount of American cropland covers about 440 million acres.