When considering the lifecycle impacts of biofuels, assessment of greenhouse gas emissions is not enough, according to two recent reports. According to the reports from the United Nations Environment Program and the U.S. Government Accountability Office a complete lifecycle analysis of environmental impacts of biofuels is necessary, including implications for air and water quality, water consumption, and wildlife habitat.
Under current U.S. law the Environmental Protection Agency (EPA) is only required to consider the lifecycle greenhouse gas emissions of biofuels. According to a renewable fuel standard mandated by the Energy Independence and Security Act of 2007, biofuels must contribute 20 percent fewer greenhouse gas emissions over their lifetime than petroleum fuels. Cellulosic biofuels would have to achieve a 60 percent reduction in emissions.
The collective environmental impacts of biofuels could extend well beyond their contribution to climate change, as reported in the October 2009 issue of BioScience. Joseph Fargione and colleagues consider the consequences of increasing bioenergy production on grassland wildlife in their article, “Bioenergy and Wildlife: Threats and Opportunities for Grassland Conservation.” As noted in the article, domestic production of bioenergy is expected to increase 740 percent between 2006 and 2022. The manner in which those fuels are produced will have large impacts on wildlife. The choice of crop type, plant diversity, fertilizer and pesticide use, harvest frequency, and other factors will greatly influence the value of habitat provided to wildlife in agricultural landscapes. Additionally, the loss of native and reclaimed prairie habitat for crop production could have dramatic impacts on grassland birds and mammals. The authors report that the loss of lands protected under the U.S. Department of Agriculture’s Conservation Reserve Program in North and South Dakota alone would result in the loss of two million grassland birds of five species.
The protection of wildlife habitat during biofuel production could come at cost to carbon emissions, the authors report. Agricultural practices that spare native prairie may increase lifecycle greenhouse gas emissions of the fuel by decreasing crop yield. Furthermore, increasing production of domestic biofuels could cause changes in land use internationally as other nations clear forests to grow crops to compensate for decreased U.S. exports. The EPA was criticized by some industry groups for considering these indirect carbon emissions in their draft renewable fuel standard released in May 2009. Pressure by lawmakers recently resulted in the EPA conceding to reflect the uncertainty of these emissions in their final rulemaking.
Fargione et al. provide several recommendations for producing bioenergy in a more sustainable manner. They recommend using biomass sources that are currently waste products in agriculture, forestry, or industry or using invasive species as sources of biomass. Algae, which would not require new agricultural lands, could also be cultivated. Additionally, the use of native prairie plants, such as switchgrass, grown in their naturally diverse stands, would preserve valuable wildlife habitat.
Meanwhile, the domestic production of cellulosic biofuel is projected to fall far short of congressionally mandated production volumes in coming years. The Biotechnology Industry Organization, a biotechnology advocacy organization, estimates that 12 million gallons will be produced next year, much less than the 100 million gallons mandated.
To read the UNEP report, please visit http://www.unep.fr/scp/rpanel/pdf/AssessingBiofuelsFullReport.pdf. To read the GAO report, please visit http://www.gao.gov/new.items/d09446.pdf. To read the BioScience article, please visit http://www.aibs.org/bioscience/bioscienceonline_2009.html.
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