There's a long and thorough post over on the Huffington post about biofuel. Does'nt like the idea of it basically because it will do bad things to Brazil. It seems to miss one or two thoughts:
Lets talk about fuel economy. Brazilian ethanol could come to the US if the tariff is removed, which could happen in 2008 at the earliest. And this could see more of the Amazon jungle turned over to sugar cane, and Brazilian grasslands too. (It was OK for the US to plough the prairie, though, apparently).
Alternatively, the US could grow more corn and convert that to ethanol, and in both cases expensive oil would stay in the ground for a little longer. Both of these scenarios also mean that there will be increasing demand for water. who will have the rights to the water? Farmers or people who live in towns and villages?
Or how about US Consumers decide that they would like less power and more miles per gallon from their cars? If fuel efficiency were to be increased then the incremental rise in demand for gasloine would slow and may possibly fall.