Pity the scientist who actually strives for the truth. She will receive no mercy from the raging hordes who troll the Net, ready to denounce any findings that contradict their own preconceptions as paid propaganda delivered by corporate tools. Case in point: On Wednesday, writing in the Wall Street Journal's Energy Blog, Keith Johnson cited the research of two University of California professors who had calculated some distressing numbers for the greenhouse gas emissions generated by corn-based ethanol production.

One of the selling points of ethanol and other biofuels has been their purported environmental friendliness relative to fossil fuels. But if you take into account the land use changes that will occur, globally, as a result of increased ethanol production in the U.S., wrote Alex Farrell and Michael O'Hare in a January 12 memo to the California Air Resources Board, corn-based ethanol could be worse than gasoline.

From the Journal:

The University of California at Berkeley's Transportation Sustainability Research Center told the California Air Resources Board that ethanol could be twice as bad as gasoline, from a carbon-emissions point of view. How? Basically by turning land now covered with trees, grass, and other natural "carbon sinks" into farmland for corn and other crops used for ethanol....

"Simply said, ethanol production today using U.S. corn contributes to the conversion of grasslands and rainforest to agriculture, causing very large GHG emissions... Even if only a small fraction of the emissions calculated in this crude way [through land use change] are added to estimates of direct emissions for corn ethanol, total emissions for corn ethanol are higher than for fossil fuels."

Farrell and O'Hare's assertions upset some commenters on the blog. The second comment:

I would like to know who are backers of The University of California at Berkeley's Transportation Sustainability Research Center? Exxon, Shell and Chevron?

And it only got worse after that. Others attacked Farrell and O'Hare for spewing "anti-agribusiness drivel" or called their report "twisted and defective... based on generalizations and false assumptions."

I had the opposite reaction as soon as I saw Farrell's name. In January 2006 I wrote about research published by Farrell and several co-authors in Science that found corn-based ethanol was more energy-efficient than some of ethanol's leading critics had long contended. Energy efficiency and greenhouse gas emissions are different beasts, of course, but the point is that his research in early 2006 gave fuel to supporters of ethanol, and his current research is pointing out some of its drawbacks. This predisposes me to trust him, a trust that is only amplified upon reading the memo, which appears to be a model of careful science.

Alex Farrell is also co-director of the team of U.C. researchers in charge of coming up with the specifications for California's "Low Carbon Fuel Standard" -- a key element in the state's ambitious attempt to minimize the greenhouse gas emissions generated by automobiles. Farrell's research, conducted explicitly on behalf of the state of California, focuses on determining "the protocols for measuring the 'life-cycle carbon intensity' of transportation fuels."

It is critically important to get this right. Reuters reported on Thursday that ethanol production capacity in the U.S. jumped by 45 percent in 2007, to nearly 7.9 billion gallons per year. Meanwhile, across the Atlantic, the European Commission unveiled a plan to combat climate change which requires any biofuels consumed in Europe produce 35 percent less greenhouse gas emissions than gasoline.

Corn-based ethanol need not apply.