clipped from: freakonomics.blogs.nytimes.com   
two newly-released studies reported that the net environmental effect of using biofuels may be even more harmful than burning the gasoline they were created to replace.
The first study
found that replacing fossil fuels with corn-based ethanol could actually double greenhouse gas emissions for the next thirty years.
The second study,
found that by switching to biofuels, we could essentially be worsening climate change for the next 93 years

So in a matter of days, biofuels go from a celebrated fossil fuels alternative to a rainforest-killing disaster, with scientists already calling for government reform on biofuel policies. If anything, this provides a window into how little we actually know about this issue, and the wide lengths left to go in reaching a viable solution.