What inspired this tirade was an E.P.A. draft proposal showing how it intended to measure the greenhouse gas emissions from corn ethanol and other renewable fuels. The agency said it will not make any final rules until it completes further research, but its preliminary findings were not flattering to corn ethanol.
The E.P.A. was only doing what Congress ordered in the 2007 energy bill, which required a quadrupling of annual ethanol production to 36 billion gallons by 2022. In practical terms, this meant more traditional corn ethanol, until other more advanced forms of ethanol could make their way out of the labs. Scientists believe that various grasses and scrub trees that do not compete with food crops can someday be turned into fuel.
Congress hoped the ethanol mandate would produce a more climate-friendly fuel that could help reduce oil imports. But just to make sure, it stipulated that ethanol from any source be cleaner than conventional gasoline. It handed the job of measuring emissions to the E.P.A., and told it to consider the fuel's entire life cycle.
This included counting the greenhouse gases released when forests or grasslands are plowed under and planted to make up for the crops used to make ethanol. When the E.P.A.'s scientists counted these indirect effects, corn ethanol emitted more greenhouse gases than gasoline over a 30-year period.
The E.P.A. says its analysis needs refinement, and in any case the 2007 bill grandfathers in existing corn ethanol plants or those under construction. That means there will not be any reduction in corn ethanol production; indeed, there could be more. Mr. Peterson and his farm bill colleagues are still steamed, because any adverse finding diminishes corn ethanol's appeal.
Lisa Jackson, the E.P.A. administrator, can expect heavy pressure in the months ahead. The ethanol industry and its Congressional champions will argue that the science is unclear, that indirect effects cannot be measured accurately, and so on.
Ms. Jackson should stand her ground. Biofuels have an important role to play, and some will eventually be produced without pushing up food prices or increasing emissions. It is the E.P.A.'s duty to give the most unbiased accounting it can of their strengths and defects.
- The New York Times