As The New York Times reported yesterday, two new studies suggest that the harvesting, production and use, or lifecycle, of biofuels like ethanol may yield more greenhouse gas emissions than fossil fuels.

Our friends at Envirovore are all over the ecological angle on this one, but there is a troubling policy story here as well. Under the Energy Policy Act of 2005, 7.5 billion gallons of renewable fuels must be blended into gasoline by 2012. It’s unclear where their numbers come from, but EPA maintains that biodiesel and E85 ethanol reduce GHG emissions by up to 50 and 20 percent, respectively, when harvesting, production and use are considered.

Something clearly doesn’t add up here, but it looks like our gas tanks will get their fill of “cleaner” fuels anyway.