Environmental Science: How green are biofuels?

Abstract

Global warming and escalating petroleum costs are creating an urgent need to find ecologically friendly fuels. Biofuels-such as ethanol from corn (maize) and sugarcane-have been increasingly heralded as a possible savior (1, 2). But others have argued that biofuels will consume vast swaths of farmland and native habitats, drive up food prices, and result in little reduction in greenhouse-gas emissions (3-5). An innovative study by Zah et al. (6), commissioned by the Swiss government, could help to resolve this debate by providing a detailed assessment of the environmental costs and benefits of different transport biofuels.