Despite ongoing controversies and setbacks, the future of biofuels looks bright.
Working with Nature Conservancy scientist Joseph Fargione, Tilman and Hill set about determining exactly how much CO2 is released by clearing land for crop biofuels, which involves burning vegetation and plowing carbon-rich soil. The results were shocking: The team found it could take decades—or even centuries—of biofuel production to make up for the amount of CO2 released during land conversion, what they called the carbon debt. For instance, it will take 93 years to make up for the carbon debt resulting from digging up central grasslands in the United States to produce corn ethanol. To repay the carbon debt for clearing peatland rainforest for oil palm biodiesel in Indonesia and Malaysia: 423 years. The only biofuel with zero carbon debt? Bioethanol from prairie biomass grown on marginal cropland.
carbon debt
The cumulative reduction of the carbon dioxide absorption or storage capacity of ecosystems, e.g. by converting land from a natural ecosystem to agricultural uses.
The results solidified Tilman’s hopes for a new type of biofuel that circumvents the problems of corn ethanol, such as fuel from switchgrass or algae. “Biofuels, if used properly, can help us balance our need for food, energy, and a habitable and sustainable environment,” Tilman wrote to the country in a 2007 opinion piece in the Washington Post. “We have the knowledge and the technology to start solving these problems.”
Select References:
Fargione, J., et al. (2008). Land clearing and the biofuel carbon debt. Science, 319(5867): 1235–1238.
Russelle, M. P., et al. (2007). Comment on “Carbon-Negative Biofuels from Low-Input High-Diversity Grassland Biomass.” Science, 316(5831):1567.
Tilman, D., et al. (2007). Response to Comment on “Carbon-Negative Biofuels from Low-Input High-Diversity Grassland Biomass.” Science, 316(5831): 1567.
Tilman, D., et al. (2006). Biodiversity and ecosystem stability in a decade-long grassland experiment. Nature, 441(7093): 629–632.
Tilman, D., et al. (2006). Carbon-negative biofuels from low-input high-diversity grassland biomass. Science, 314(5805): 1598–1600.
PERSONAL CHOICES THAT HELP
Biofuels represent a potential replacement for fossil fuels and might be especially important fuels for transportation. Despite the promise of biofuel use, there are also trade-offs, such as the fossil fuel inputs needed to grow fuel crops. Developing new biofuel technologies may help us meet the energy needs of the future.
Individual Steps
Visit ecogeek.org to find information on experiments and new advances in biofuel technology.
Review Infographic 32.6 and take steps to make your vehicle and driving more fuel efficient; make the investment in a hybrid or electric vehicle if you can.
Group Action
Host a movie night to watch FUEL, an award-winning film that looks at the history of biofuels as well as possible solutions for the future.
Follow the Veggie Van Organization on Facebook and Twitter to see which schools they are visiting and to see how they use their biofuel vehicles for education.
Policy Change
Use the Advanced Biofuels USA site (advancedbiofuelsusa.info) to learn about sustainable biofuel options and stay current on proposed biofuel legislation.
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