The studies are out in this week's Science: when one takes account of the impact of land use, bio-fuels can generate more greenhouse gases than they save.
It seems the only biofuels that help are those made from agricultural waste.
Think about it: even if no new land is cleared to grow crops for biofuels, people growing those crops are going to have to a) clear new land to grow food or b) import their food from somewhere else. And soils are being depleted even more rapidly in middle America as the conventional rotation of corn and soy is being abandoned for corn, corn, corn and corn. Meanwhile rainforests in the global south are begin destroyed to grow the soy beans for our imported pig feed.
What is wrong with this picture?
A spokesperson for the UN Energy Program is quoted in the NY Times this week confessing the error of "dressing up biofuels as the silver bullet of climate change."
Suppose there is no silver bullet (and no Lone Ranger or Tonto either) - we are then left with accepting our planet's limits, and reducing our energy usage.
The carbon cycle just IS folks - and there are no long term ways to affect it, change it, short circuit it, whatever. I want to think I am oversimplifying - but harking back to college courses in ecology, I doubt it. There are limits to what we humans can do can change the basic nature of reality, and it seems to me that using our wits and technological acumen to reduce energy usage from carbon in dead plants (whether dead yesterday or eons ago), while at the same time building community that is both strongly local and connected, is the only sane alternative.