What researchers found was a vast creation of carbon in the conversion of peatlands for Indonesian palm oil plantations and soy production in the Amazon. The research led Fargione to conclude that biofuel, if farmed from converted land, is not a practical replacement for fossil fuels.
Fargione also argues that the findings call into question the energy bill recently passed by Congress, which calls for increased biofuel production — 15 billion gallons by 2015.
"If you create a carbon tax or a low carbon fuel standard that penalizes fuel based on the amount of carbon it emits and then you miscalculate how much carbon biofuels are actually emitting, then biofuels are actually worse than the fossil fuels they replace," he said.
But according to the Renewable Fuels Association, a trade organization representing the U.S. ethanol industry, the studies failed to put biofuel production in context with fossil fuel production.
"Without biofuels and some increase in fuel economy, more and more petroleum will be required to meet the increasingly ravenous demand for liquid fuels around the world," Bob Dinneen, the association's president, said in a statement. "As the 'easy' sources of oil decline, development of exotic resources, like tar sands in Canada, are being pursued. Tar sands, by comparison, release some 300 percent more greenhouse gas emissions than traditional petroleum recovery."
For those committed to biofuel, there is hope, both sets of researchers said, in biofuel made from abandoned, depleted farmland and biomass waste, like unused parts of a corn plant.
"The holes from your Cheerios could be used for energy," Fargione said.
Still, Fargione maintains that biofuels aren't the only answer in the fight against global warming.
"It's worth doing, but it's not a silver bullet," he said.