Arguments in favor of bioethanol (and other biofuels) tend to mix some (or all) of four key points, variously worded, and with different degrees of urgency:

• Fossil energy resources are finite and may become seriously depleted before 2050 (the “peak oil” argument — see chapter 5, section 5.6).

• Biofuels avoid dependency on oil imports (the “energy security” argument).

• Biofuels augment sustainable development across the globe, more efficiently utilizing agricultural wastes (the “long-term environmental” argument).

• Biofuels can reduce greenhouse gas and other harmful emissions (the “acute climatic” argument).

Economists and socioeconomists tend to concentrate the first two cases, whereas biological scientists are far more comfortable with the latter two arguments. So far, the present discussion has touched on topics pertinent to the “energy security” problem, but conflicting data and conclusions have been apparent for nearly three decades on how biofuels (and bioethanol in particular) may — or may not — be solu­tions to the global energy supply and the ecological crisis of global warming caused by greenhouse gas emissions.