Chapter 7. Positive and Negative Impacts of Agricultural Production of Liquid Biofuels

Abstract

Agricultural production of liquid biofuels can have positive effects. It can decrease dependence on fossil fuels and increase farmers’ incomes. Agricultural production of mixed perennial biofuel crops may increase pollinator and avian richness. Most types of agricultural crop-based liquid biofuel production, however, have a negative effect on natural ecosystems and biodiversity. Comparisons of fossil fuels and liquid biofuels regarding their life cycle emissions of pollutants which are (eco)toxic or contribute to oxidizing smog, acidification or nutrification give mixed results. Fossil fuels often do better than biofuels as to emissions of acidifying and nutrifying substances, but often worse regarding ecotoxicity. A rapid increase in biofuel production can increase malnutrition due to its upward effect on food prices. Liquid biofuel lifecycles are linked to greater water consumption than their fossil fuel counterparts. Life cycle greenhouse gas emissions of liquid agricultural biofuels are currently often larger than those of their fossil fuel counterparts, when effects of land use on carbon stocks are included. An exception in this respect is current Brazilian sugarcane ethanol. When soil quality is to be maintained, there seems to be little scope to convert lignocellulosic harvest residues into liquid biofuels. Agricultural biofuels are much poorer converters of solar energy into usable energy than photovoltaic cells.