Slashdot has an entry that ought to give us pause before betting the farm (literally in some cases) on biofuels as a replacement for fossil fuels. (The main link is to a Seattle Times article).
The benefits of biofuels have come under increasing attack in recent months, as scientists took a closer look at the global environmental cost of their production. These plant-based fuels were originally billed as better than fossil fuels because the carbon released when they were burned was balanced by the carbon absorbed when the plants grew. But that equation proved overly simplistic because the process of turning plants into fuels causes its own emissions — for refining and transport, for example. These studies… for the first time take a detailed, comprehensive look at the emissions effects of the huge amount of natural land that is being converted to cropland globally to support biofuels development.
In short, the studies suggest that the biofuels might produce more greenhouse gases than fossil fuels. Even if these studies are accurate, there might be short term reasons to prefer biofuels to fossil fuels – shortages of the latter, geopolitical reasons – our oil is buried under some pretty unstable countries; etc. But, we should keep looking for better energy sources.