Two new studies published in Science (here and here) suggest that the use and production of biofuels substantially increases greenhouse gas emissions, particularly if such fuels are produced from food crops. Unlike prior studies, these reports sought to account for the loss of carbon storage due to the land conversion necessary to grow biofuel feedstocks. Once this factor is taken into account, both studies found, conversion to biofuels are big greenhouse losers. As the New York Times reported:

The destruction of natural ecosystems — whether rain forest in the tropics or grasslands in South America — not only releases greenhouse gases into the atmosphere when they are burned and plowed, but also deprives the planet of natural sponges to absorb carbon emissions. Cropland also absorbs far less carbon than the rain forests or even scrubland that it replaces.

Together the two studies offer sweeping conclusions: It does not matter if it is rain forest or scrubland that is cleared, the greenhouse gas contribution is significant. More important, they discovered that, taken globally, the production of almost all biofuels resulted, directly or indirectly, intentionally or not, in new lands being cleared, either for food or fuel.

"When you take this into account, most of the biofuel that people are using or planning to use would probably increase greenhouse gasses substantially," said Timothy Searchinger, lead author of one of the studies and a researcher in environment and economics at Princeton University. "Previously there's been an accounting error: land use change has been left out of prior analysis."

The actual studies are not all bad news for biofuels, however. Both suggest that the production of biofuels from waste products could produce greenhouse gas reductions, and one of the studies suggests potential GHG emission savings from the production of biofuels from perennial grasses. Neither study has anything good to say about corn-based ethanol.

If we want to know the full environmental toll of biofuels there are additional factors to consider. Particularly when biofuel production requires the use or conversion of cropland, as with corn-based ethanol, these costs include increased water use (which is becoming a problem in parts of the midwest) and the loss of migratory bird habitat. The bottom line is that the energy "solution" most favored by the political class is no solution at all.