[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]
The corn growing in fields across the Midwest will find a variety of uses after harvest this fall. Much will become food, either as classic corn on the cob, or the high fructose corn syrup in soft drinks, or as the animal feed that makes burgers.
But some will be fermented into the alcohol we know as ethanol and, by government mandate, blended into the nation's transportation fuel supply. The U.S. hopes to get 15 billion gallons of ethanol by 2015.
That may be good news for farmers but it doesn't help the world's eaters. Competition between food and fuel last year when oil reached $145 a barrel provoked riots from Mexico to Bangladesh.
And the potential for a crop price bonanza drives the cutting down of rainforests and heavy fertilizer application causing climate change and oceanic dead zones respectively.
Those problems might or might not be solved by more advanced biofuels, such as those made from the non-food or cellulosic parts of crop plants or even non-food crops such as switchgrass or algae. And a recent study found that burning such biomass to produce electricity delivered more environmental benefits than transforming it into liquid fuels.
So it seems that biofuels might not be the best solution for weaning the world off oil.