The problem isn't with the cars, the problem is with what it takes to grow the biofuel in the first place. Clearing the land, harvesting, and refining the crops, plus the loss of forest and wild lands and habitats, amounts to creating a carbon footprint worse than fossil fuels. According to the Science article which, admittedly, posits an extreme scenario, it would take 423 years to even out the carbon debt if Indonesia's peat lands were converted to palm oil fields.
The research is starting to give some people pause, such as the folks at the European Union who declared they wanted ten-percent of the block's transport fuel to come from plants. And Joe Fargione of the U.S. Nature Conservancy asks, "Is it worth it? ...[S]urprisingly the answer is 'no'. These natural areas store a lot of carbon, so converting them to crops results in tons of carbon emitted into the atmosphere."
Thanks for the tip, Zo!
[Source: MSN Money]