Biofuel Research Suffers From Gaps

After a review of a decade’s worth of biofuels research, scientists with the Environmental Protection Agency have concluded that significant knowledge gaps will likely prevent experts from adequately assessing biofuels’ full environmental impacts (Environ. Sci. Technol., DOI: 10.1021/es2023253). While researchers have paid substantial attention to greenhouse gas emissions, the new study says, they have focused little on how the production and use of biofuels affects biodiversity and human health.

“The last 10 years or so of research may have left us short of understanding what biofuels really may do to global economies, the environment, and society,” says Caroline Ridley, an ecologist with the EPA’s National Center for Environmental Assessment, in Arlington, Va., who led the study.

Interest in biofuels has grown in part because the U.S. government has mandated aggressive expansion of their production. One job of Ridley’s group is to synthesize available information on such environmental policies.

She and her colleagues searched literature databases to identify more than 1,600 biofuels research citations from 2000 to 2009. They assigned each study to one of four themes, such as the environment or economics, and then to topics within those themes, such as greenhouse gas emissions or costs of production. They also looked at each study’s geographical focus and whether the papers connected different topics.

The team found that the most common topics, with a few hundred papers each, were fuel production, feedstock production, and greenhouse gas emissions. Near the bottom of the list, 80 studies examined how biofuel production affects biodiversity, for example how local species fare after farmers clear large stretches of land to grow corn, switchgrass, palm oil, or other biofuel feedstocks. And only 15 studied the human health impacts of increasing levels of air pollutants produced by burning biofuel ethanol.

The team also found that researchers have focused largely on the environmental consequences in the Northern Hemisphere even though regions in the Southern Hemisphere, such as Indonesia, will probably grow most of the feedstock crops.

Jason Hill, an environmental scientist at the University of Minnesota, Twin Cities, who was a coauthor of a recent National Academy of Sciences biofuels report, finds the EPA team’s review refreshing because it identifies what he calls an unbalanced focus on greenhouse gas emissions in biofuels research. The impacts on biodiversity and human health “are at least as large as the potential damage from climate change,” he says.

Ridley and her team warn that these holes in biofuels research mean that expanded biofuels use could lead to unanticipated problems. As a result, she suggests her team’s results could offer a useful guide to decision makers in allotting research funds. Hill agrees and sees the review as a call for scientists to fill in the gaps.