Further reading for the interested:

- "All studies indicated that current corn ethanol technologies are much less petroleum-intensive than gasoline but have greenhouse gas emissions similar to those of gasoline. However, many important environmental effects of biofuel production are poorly understood. New metrics that measure specific resource inputs are developed, but further research into environmental metrics is needed. Nonetheless, it is already clear that large-scale use of ethanol for fuel will almost certainly require cellulosic technology. " http://www.sciencemag.org/content/311/5760/506

- "[Prior] analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. " http://www.whrc.org/resources/publications/pdf/Searchingeret...

This second citation is key. Most of my friends who aren't studying this stuff all the time aren't aware of the critical role land use changes (e.g. deforestation) plays in global carbon emissions, and biofuel's perturbation of international food markets tends to accelerate these deleterious trends.