If a Tree Falls in the Forest, Are Biofuels To Blame? It's Not Easy Being Green

By STEPHEN POWER

Biofuels are under siege from critics who say they crowd out food production. Now these fuels made from grass and grain, long touted as green, are being criticized as bad for the planet.
At issue is whether oil alternatives -- such as ethanol distilled from corn and fuels made from inedible stuff like switch grass -- actually make global warming worse through their indirect impact on land use around the world.

For example, if farmers in Brazil burn and clear more rainforest to grow food because farmers in the U.S. are using their land to grow grain for fuel, that could mean a net increase in emissions of carbon dioxide, the main "greenhouse gas" linked to climate change.
The issue has been heating up for months in scientific, corporate and environmental circles. Now, the Environmental Protection Agency has indicated it plans to measure each biofuel's emissions based partly on the ripple effect that its production in the U.S. can have overseas, and is preparing to seek comments on a proposal. Some scientists, as well as General Motors Corp., DuPont Co., Archer-Daniels-Midland Co. and other companies with an interest in the outcome, are warning of a muddled calculus.
"If population grows in America and therefore ... we need to build a new Wal-Mart, are we going to debit that pregnant woman with the indirect life-cycle greenhouse-gas footprint of her decision to have that child?" says Michael Parr, a senior government affairs manager at DuPont.
Environmental groups say disclosing the emissions levels associated with land-use change caused by biofuels is critical to determining which fuels will best help the U.S. reduce its dependence on oil.
A study published in February in the journal Science found that U.S. production of corn-based ethanol increases emissions by 93%, compared with using gasoline, when expected world-wide land-use changes are taken into account. Applying the same methodology to biofuels made from switch grass grown on soil diverted from raising corn, the study found that greenhouse-gas emissions would rise by 50%.
Previous studies have found that substituting biofuels for gasoline reduces greenhouse gases. Those studies generally didn't account for the carbon emissions that occur as farmers world-wide respond to higher food prices and convert forest and grassland to cropland.
But some scientists and many biofuel proponents have challenged the Science study, saying it relied on unrealistic assumptions. And there is disagreement among scientists and economists over how to measure the impact of land-use changes in one country on land-use changes in another. When a Brazilian farmer chops down rainforest to grow a crop, for instance, how can the EPA be sure his decision wasn't influenced by local factors, such as the construction of a new highway that made it easier to bring the crop to market?
DuPont, ADM, GM and representatives of the biotechnology industry have asked that the EPA hold off on quantifying the greenhouse-gas impacts of so-called indirect land-use change, and instead seek comment on the methodology the agency plans to use. The companies, along with some scientists, say that methods for measuring such indirect effects are still new, and that trying to assess emissions levels based on immature methods could lead to unwarranted conclusions that would discourage investment in biofuels.
An EPA spokesman declined to speculate on "what is or isn't" going to be in the administration's proposal. The agency's efforts are driven by a 2007 energy law that says the EPA, in determining each fuel's "lifecycle greenhouse-gas emissions," must consider "direct emissions and significant indirect emissions such as significant emissions from land use changes."
Bruce Dale, a chemical-engineering professor at Michigan State University, says he is skeptical that policy makers can establish an accurate system for gauging the indirect effect of biofuel production on overseas land use. "All this stuff is accounting," which in turns depends on data and "assumptions you make about how the world works," he says.
Nathanael Greene, director of renewable-energy policy at the Natural Resources Defense Council, acknowledges the difficulty of quantifying emissions levels associated with indirect land-use change. But he says that isn't a valid reason for not trying to measure them.
If anything, Mr. Greene says, biofuels producers -- particularly those that specialize in making fuels that don't come from corn -- stand to benefit from new regulations, because such standards will "inoculate" the industry against the kinds of criticisms that have buffeted food-based biofuel crops.
"This industry, like many other industries, relies on government subsidies," Mr. Greene says. "If public opinion turns against [advanced biofuel producers] because they're associated with clear-cutting forests and harming endangered species ... those incentives and that public support are going to evaporate."
Write to Stephen Power at stephen.power@wsj.com