WorldChanging is running an in-depth series on biofuels, which is moderately pro-.

The first installment discusses this study and another one:

WorldChanging: Growing Sustainable Biofuels: Common Sense on Biofuels

Biofuels received a fresh surge of bad publicity with recent publication of two studies in Science that looked at the greenhouse gas releases caused by land use changes connected to biofuels production.  

The studies make complex and nuanced statements that were predictably mangled by the press, with headlines easily interpreted as a general condemnation of biofuels. Typical was the New York Times, "Biofuels Deemed a Greenhouse Threat," The studies were creating new uncertainties even among biofuels supporters and tipping others toward a skeptical position.  At very least the studies add to substantial public perception problems facing biofuels.  

So it is crucial to line out exactly what the studies say, what they do not say, and what the critics are saying about the studies.  

The second part is more interesting, and makes the very important point that it's all about soil:

WorldChanging: Growing Sustainable Biofuels: Common Sense on Biofuels, part 2

The future of the Earth could well hinge on the future of earth, the soil beneath our feet.

One statistic makes clear why - soils and plants growing on them contain 2.7 times more carbon than the atmosphere.  Outside the oceans they represent the Earth's largest store of biological carbon.  Using soils and plants in ways that release carbon intensifies climate change.  This is the second greatest source of climate-disrupting greenhouse gases after fossil-fuel burning.  

On the other hand, employing the land to soak up atmospheric carbon increasingly appears central to averting global climate meltdown, quite literally.  Carbon levels in the atmosphere may have already reached a point where simply stopping the increase in greenhouse gas concentrations may not be enough to stop the worst climate change impacts. Whether massive loss of polar ice and sea level rises measured in the tens of feet can be prevented may very well depend on the skill of farmers and foresters in growing soil carbon.  

My gripe about this is that even sustainable, cellulosic biofuels are not going to add up to enough oil. Maybe a 10% target could be reached, but that's still a partial and not a long-term solution. Perhaps algal biofuels will have more potential, but those are even more hypothetical, and are in comparison still far less effective than solar. At the same time, with oil you keep the ambient emissions from the internal combustion engine.

The money available for public investment in green technologies is unfortunately limited, and I would prefer to see it spent on the most promising solutions, which means not on biofuels or, for another example, carbon capture and storage, but on concentrated solar, photovoltaics, wind, tidal, electricity storage either in batteries or by other means.