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Author(s): Joseph Fargione, Jason Hill, David Tilman, Stephen Polasky, and Peter Hawthorne
Timothy Searchinger, Ralph Heimlich, R. A. Houghton, Fengxia Dong, Amani Elobeid, Jacinto Fabiosa, Simla Tokgoz, Dermot Hayes, and Tun-Hsiang Yu
Citation: Science 29 February 2008: 1235-1238
Science 29 February 2008: 1238-1240
URL: http://www.sciencemag.org/cgi/content/full/319/5867/1235 (Full Text of Fargione et al)
URL: http://www.sciencemag.org/cgi/content/full/319/5867/1238 (Full Text of Searchinger et al)
URL: http://www.sciencemag.org/cgi/content/full/319/5867/1238
Although biofuels have the potential to reduce CO2 emissions, secondary effects of biofuel production must also be considered, such as how much CO2 is released by the conversion of land to the production of biofuel stock. Fargione et al. analyze the carbon balance of the conversion of a variety of carbon-rich land types to food-based biofuel croplands and find that the carbon debt incurred by the conversion process can be as much as 420 times that of the annual greenhouse gas emission reductions that result from the displacement of fossil fuels from the energy generation process. Biofuels made from waste biomass, or grown on abandoned agricultural lands, can avoid most, or even all, of that carbon debt, however. Searchinger et al. have modeled greenhouse gas emissions in the production of corn-based ethanol. Instead of generating a roughly 20% reduction in greenhouse gases, as typically is claimed, emissions would approximately double during the first 30 years of implementation and create an emission increase that would take more than 160 years to recoup.
This Document is classified within these Core Themes:
Health and Environment
Environment
Energy
Agriculture
Impacts and response
Using large data sets
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