The Ecological Impact of Biofuels

Abstract

The ecological impact of biofuels is mediated through their effects on land, air, and water. In 2008, about 33.3 million ha were used to produce food-based biofuels and their coproducts. Biofuel production from food crops is expected to increase 170% by 2020. Economic model estimates for land-use change (LUC) associated with food-based biofuels are 67–365 ha 10−6 l−1, leading to increased greenhouse gas emissions for decades compared to business as usual. Biodiversity is reduced by about 60% in U.S. corn and soybean fields and by about 85% in Southeast Asian oil palm plantations compared to unconverted habitat. Consequently, the largest ecological impact of biofuel production may well come from market-mediated LUC. Mitigating this impact requires targeting biofuel production to degraded and abandoned cropland and rangeland; increasing crop yields and livestock production efficiency; use of wastes, residues, and wildlife-friendly crops; and compensatory offsite mitigation for residual direct and indirect impacts.