I'm all for alternative, non-petroleum-based fuel sources. I look happily forward to a future fueled by wind, solar, geothermal and hydrogen.
While biofuels have their advantages, they might be making the supposed "global warming" problem worse. The reason is simple: massive deforestation is taking place to meet the explosive demand for land for biofuel crops.
This is not a newly recognized problem. Environmentalists have been watching this happen for several years now and have tried to point this out, but no one seems to want to hear about it.
Here's just one article on the subject.