The case for Big Ag: industrial farming pollutes rivers, distorts politics, and hurts rural communities. But it might just save the rainforest.

• Author: Grunwald, Michael
• Position: SPECIAL REPORT

Once upon a time--actually, it was just two years ago--almost everyone in the scientific and environmental communities thought of farm-grown biofuels as a green alternative to gasoline, a renewable win-win solution that would decrease global warming as well as increase agricultural incomes. Then an environmental lawyer named Tim Searchinger had an epiphany, and proved that almost everyone was wrong.

Searchinger wasn't a scientist, an economist, or an agronomist, and he was new to energy issues. But he had spent years analyzing and litigating the ecological impacts of agriculture, especially its intrusions into natural habitats, and he wasn't the kind of enviro who assumed that something was good just because it was "renewable." So he dug into the literature. A slew of studies had concluded that crop-based fuels would slash carbon emissions, mainly because the act of growing crops removes carbon from the atmosphere. But Searchinger realized the studies had completely ignored the real-world implications of devoting crops to cars instead of people. This was his epiphany: in a world with 6.7 billion mouths to feed, when you use an acre of farmland to grow fuel, somewhere an acre of something else is probably going to be converted into new farmland to grow food, and that something else is likely to be forests or wetlands that store far more carbon than farmland ever could. It certainly isn't going to be a parking lot, which was the implicit assumption of the earlier studies.

And sure enough, when Searchinger and others began incorporating these indirect land-use effects into their green-house gas assessments, they found that when biofuels use productive land, the emissions created by induced deforestation outweigh the carbon benefits-while increasing hunger and decreasing biodiversity, to boot.

Oops!

"The most pungent critique I've had was a scientist who just said, 'No duh!,'" says Searchinger, now a scholar at Princeton. "It all seems so obvious in retrospect."

The impact of this analytical booboo has been staggering. The United States and Europe have already enacted strict mandates for biofuel usage that are ravaging the planet in the name of saving it, jump-starting a $100 billion global industry in renewable fuels, forcing beleaguered automakers to manufacture counterproductive "flex-fuel" vehicles, artificially boosting demand for grain, and creating a deadly competition between the 800 million (and rising) people with cars and the 800 million (and rising) people with hunger problems. The grain it takes to fill an SUV's tank could feed an adult for a year, and the United States is now diverting one-fourth of its corn crop to ethanol, which has helped spark riots to protest rising food prices in countries like Haiti, Mexico, and Pakistan.

It has also ratcheted up deforestation rates through a chain reaction that Searchinger and I witnessed on a visit to the Amazon last year: as U.S. soybean farmers switch to corn to take advantage of the ethanol boom, Brazilian...