Brad Plumer highlights a GAO report against corn ethanol:
There's ample evidence that the ongoing corn- and soy-ethanol frenzy in the United States and Europe has indirectly fostered deforestation and jacked up food prices. A 2008 Science study found that these "first-generation" biofuels produce nearly twice as many greenhouse-gas emissions as gasoline, once you factor in all the indirect land-use effects. Alas, Congress is tilted toward rural and farm interests by design, which means corn ethanol isn't slinking away anytime soon. Still, we could at least start with small stepsthere's really no need for these subsidies, which total some $4 billion per year (and will rise to $6.75 billion per year by 2015).