Corned grief: biofuels may increase CO2

In the March 2010 issue of BioScience, researchers present a sophisticated new analysis of the effects of boosting use of maize-derived ethanol on greenhouse gas emissions. The study, conducted by Thomas W. Hertel of Purdue University and five co-authors, focuses on how mandated increases in production of the biofuel in the United States will trigger land-use changes domestically and elsewhere. In response to the increased demand for maize, farmers convert additional land to crops, and this conversion can boost carbon dioxide emissions. The analysis combines ecological data with a global economic commodity and trade model to project the effects of US maize ethanol production on carbon dioxide emissions resulting from land-use changes in 18 regions across the globe. The researchers’ main conclusion is stark: These indirect, market-mediated effects on greenhouse gas emissions “are enough to cancel out the benefits the corn ethanol has on global warming.” The indirect effects of increasing production of maize ethanol were first addressed in 2008 by Timothy Searchinger and his coauthors, who presented a simpler calculation in Science. Searchinger concluded that burning maize ethanol...read more