E-Letter responses to:

reports: Timothy Searchinger, Ralph Heimlich, R. A. Houghton, Fengxia Dong, Amani Elobeid, Jacinto Fabiosa, Simla Tokgoz, Dermot Hayes, and Tun-Hsiang Yu Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change Science 2008; 319: 1238-1240 [Abstract] [Full text] [PDF]

E-Letters: Submit a response to this article

Published E-Letter responses:

Food, Land Use Changes, and Biofuels

Steven A. Kolmes   (25 March 2008)

Food, Land Use Changes, and Biofuels 25 March 2008
Steven A. Kolmes, Professor University of Portland Respond to this E-Letter: Re: Food, Land Use Changes, and Biofuels	T. Searchinger et al. [as well as Fargione et al. (1)] make the case that whether biofuel production has a net greenhouse gas benefit depends on land use changes as large new areas are converted to agricultural uses and a carbon debt is incurred. Alternatively, dietary changes in the United States could free vast areas for biofuel production without converting more land to agricultural use. Beef requires 13 kg of grain and 30 kg of forage per kg of meat produced; broiler chickens, 2.3 kg of grain per kg of meat. Additionally, beef production requires 57 kcal of fossil fuel for each kcal of food gained, while broiler chickens have a 4:1 ratio (2). The FAO estimates cattle rearing and processing accounts for 18% of global greenhouse gas emissions (3). The U.S. grows slightly under 40 million hectares of corn and roughly 25 million hectares of soybeans (4). A little over half the corn we grow goes into animal feed (5). Over half the soybeans grown in the U.S. are crushed for soymeal and oil, and approximately 90% of the soymeal produced goes into livestock feed for meat (6). A lacto-ovo-vegetarian diet (dairy, eggs, plants) also requires animal feed, but about half as much as a meat-heavy American diet (2). If the U.S. consumed less red meat, millions of hectares in corn or soy production could be used for ethanol or biodiesel, with no undesirable land use alterations and hence no additional carbon debt. Fossil fuel demand would also be reduced if we moved away from the 57:1 ratio mentioned above. Additionally, livestock produce methane, a potent greenhouse gas. Moderating our carnivory could therefore help reduce what are presently abnormally high atmospheric methane levels (7). We don’t need to wait for technological advances in lignocellulosic ethanol to make biofuel production an important component of atmospheric carbon reduction. We just need to eat as though we live on a finite planet. Steven A. Kolmes Environmental Studies Program, University of Portland, Portland, Oregon 97203, USA. References 1. J. Fargione, J. Hill, D. Tilman, S. Polasky, P. Hawthorne, Science 319, 1235 (2008). 2. D. Pimentel, M. Pimentel, Am. J. Clinical Nutrition 78, 660S (2003). 3. H. Steinfeld et al., Livestock’s Long Shadow, Environmental Issues and Options, Food and Agriculture Organization of the United Nations, ISBN 978- 92-5-105571-1 (2006) (available at http://www.virtualcentre.org/en/library/key_pub/longshad/A0701E00.pdf). 4. National Agricultural Statistics Service, USDA, Report Released June 29, 2007 (available at http://www.usda.gov/nass/PUBS/TODAYRPT/acrg0607.txt). 5. E. Leibtag, Amberwaves (2008) (available at http://www.ers.usda.gov/AmberWaves/February08/Features/CornPrices.htm). 6. Soy Stats, 2007, available at http://www.soystats.com/2007/Default- frames.htm (Sponsored by the Illinois Soybean Association, Indiana Soybean Alliance, Minnesota Soybean Research & Promotion Council, North Dakota Soybean Council, Ohio Soybean Council, Iowa Soybean Association, South Dakota Soybean Research & Promotion Council, and the Kentucky Soybean Board.) 7. J. R. Petit et al., Nature 399, 429 (1999).