Global warming is one of the most serious challenges humankind has ever faced. The U.S. National Academy of Sciences, the U.N. Intergovernmental Panel on Climate Change (Parry et al. 2007), and scientific academies of 10 nations have all stated that human activity is changing our climate at an unprecedented rate. Every time we drive a car, use electricity from coal-fired power plants, or heat our homes with oil or natural gas, we release carbon dioxide (CO₂) and other heat-trapping gases into the air. We therefore have a fundamental responsibility to future generations to address this profound threat to the natural...

Currently, many stakeholders at the state, federal, and international levels are working to develop improved systems for estimating emissions of CO₂ and other heat-trapping gases from transportation fuels including biofuels. California’s regulatory agencies, for example, are working with stakeholders to develop such a system for the state’s Low Carbon Fuel Standard, and a similar effort led by the U.S. Environmental Protection Agency (EPA) is beginning to take shape at the federal level. European countries such as the Netherlands and United Kingdom are developing tools to assess individual biofuel supply chains more consistently.

These governmental agencies are all struggling to develop...

Biofuels may have the potential to displace up to one-quarter of the United States’ transportation fuels over the next two decades, depending on advances in vehicle and fuel technologies and policies (English et al. 2006, Perlack et al. 2005). But without requirements to minimize global warming pollution and ensure sustainable fuel production, a significant expansion of biofuels could lead to increased global warming pollution, loss of open space and biodiversity, and other harmful impacts.

As discussed in the previous chapter, a better route must start with an understanding of the carbon footprint of all fuels. Using this information, we can...

Low-carbon biofuels have the potential to help our nation increase its energy security, promote economic development, and decrease global warming pollution. Biofuels have a significant advantage over higher-carbon alternatives, but only when viewed in terms of life cycle emissions.

In the agriculture sector, increased demand for lower-carbon biofuels will create new markets for biomass crops and new demand for old by-products. The U.S. economy as a whole will benefit from the development and deployment of new technologies, which provide new job opportunities for scientists, engineers, construction workers, and many others. And most important, low-carbon biofuels combined with sound economic incentives...