Chapter 2. Beyond the Oil Peak: The Oil Intensity of Food
Modern agriculture depends heavily on the use of gasoline and diesel fuel in tractors for plowing, planting, cultivating, and harvesting. Irrigation pumps use diesel fuel, natural gas, and coal-fired electricity. Fertilizer production is also energy-intensive: the mining, manufacture, and international transport of phosphates and potash all depend on oil. Natural gas, however, is used to synthesize the basic ammonia building block in nitrogen fertilizers. 16
In the United States, for which reliable historical data are available, the combined use of gasoline and diesel fuel in agriculture has fallen from its historical high of 7.7 billion gallons in 1973 to 4.6 billion in 2002, a decline of 40 percent. For a broad sense of the fuel efficiency trend in U.S. agriculture, the gallons of fuel used per ton of grain produced dropped from 33 in 1973 to 13 in 2002, an impressive decrease of 59 percent. 17
One reason for this was a shift to minimum and no-till cultural practices on roughly two fifths of U.S. cropland. No-till cultural practices are now used on roughly 95 million hectares worldwide, nearly all of them concentrated in the United States, Brazil, Argentina, and Canada. The United States—with 25 million hectares of minimum or no-till—leads the field, closely followed by Brazil. 18
While U.S. agricultural use of gasoline and diesel has been declining, in many developing countries it is rising as the shift from draft animals to tractors continues. A generation ago, for example, cropland in China was tilled largely by animals. Today much of the plowing is done with tractors. 19
Fertilizer accounts for 20 percent of U.S. farm energy use. Worldwide, the figure may be slightly higher. On average, the world produces 13 tons of grain for each ton of fertilizer used. But this varies widely among countries. For example, in China a ton of fertilizer yields 9 tons of grain, in India it yields 11 tons, and in the United States, 18 tons. 20
U.S. fertilizer efficiency is high because U.S. farmers routinely test their soils to precisely determine crop nutrient needs and because the United States is also the leading producer of soybeans, a leguminous crop that fixes nitrogen in the soil. Soybeans, which rival corn for area planted in the United States, are commonly grown in rotation with corn and, to a lesser degree, with winter wheat. Since corn has a voracious appetite for nitrogen, alternating corn and soybeans in a two-year rotation substantially reduces the nitrogen fertilizer needed for the corn. 21
Urbanization increases demand for fertilizer. As rural people migrate to cities, it becomes more difficult to recycle the nutrients in human waste back into the soil. Beyond this, the growing international food trade can separate producer and consumer by thousands of miles, further disrupting the nutrient cycle. The United States, for example, exports some 80 million tons of grain per year—grain that contains large quantities of basic plant nutrients: nitrogen, phosphorus, and potassium. The ongoing export of these nutrients would slowly drain the inherent fertility from U.S. cropland if the nutrients were not replaced in chemical form. 22
Factory farms, like cities, tend to separate producer and consumer, making it difficult to recycle nutrients. Indeed, the nutrients in animal waste that are an asset to farmers become a liability in large feeding operations, often with costly disposal. As oil, and thus fertilizer, become more costly, the economics of factory farms may become less attractive.
Irrigation, another major energy claimant, is taking more and more energy worldwide. In the United States, close to 19 percent of agricultural energy use is for pumping water. In the other two large food producers—China and India—the number is undoubtedly much higher, since irrigation figures so prominently in both countries. 23
Since 1950 the world’s irrigated area has tripled, climbing from 94 million hectares to 277 million hectares in 2002. In addition, the shift from large dams with gravity-fed canal systems that dominated the last century’s third quarter to drilled wells that tap underground water resources has also boosted irrigation fuel use. 24
Some trends, such as the shift to no tillage, are making agriculture less oil-intensive. But rising fertilizer use, the spread of farm mechanization, and falling water tables are making food production more oil-dependent. This helps explain why farmers are becoming involved in the production of biofuels, both ethanol to replace gasoline and biodiesel to replace diesel. (Renewed interest in these fuels is discussed later in this chapter.)
Although attention commonly focuses on energy use on the farm, this accounts for only one fifth of total food system energy use in the United States. Transport, processing, packaging, marketing, and kitchen preparation of food account for nearly four fifths of food system energy use. Indeed, my colleague Danielle Murray notes that the U.S. food economy uses as much energy as France does in its entire economy. 25
The 14 percent of energy used in the food system to move goods from farmer to consumer is roughly equal to two thirds of the energy used to produce the food. And an estimated 16 percent of food system energy use is devoted to processing—canning, freezing, and drying food—everything from frozen orange juice concentrate to canned peas. 26
Food staples, such as wheat, have traditionally moved over long distances by ship, traveling from the United States to Europe, for example. What is new is the shipment of fresh fruits and vegetables over vast distances by air. Few economic activities are more energy-intensive. 27
Food miles—the distance food travels from producer to consumer—have risen with cheap oil. Among the longest hauls are the flights during the northern hemisphere winter that carry fresh produce, such as blueberries from New Zealand to the United Kingdom. At my local supermarket in downtown Washington, D.C., the fresh grapes in winter typically come by plane from Chile, traveling almost 5,000 miles. Occasionally they come from South Africa, in which case the distance from grape arbor to dining room table is 8,000 miles, nearly a third of the way around the earth. 28
One of the most routine long-distance movements of fresh produce is from California to the heavily populated U.S. East Coast. Most of this produce moves by refrigerated trucks. In assessing the future of long-distance produce transport, one oil analyst observed that the days of the 3,000-mile Caesar salad may be numbered. 29
Packaging is also surprisingly energy-intensive, accounting for 7 percent of food system energy use. It is not uncommon for the energy invested in packaging to exceed that of the food it contains. And worse, nearly all the packaging in a modern supermarket is designed to be discarded after one use. 30
The most energy-intensive segment of the food chain is the kitchen. Much more energy is used to refrigerate and prepare food in the home than is used to produce it in the first place. The big energy user in the food system is the kitchen refrigerator, not the farm tractor. 31
While the use of oil dominates the production end of the food system, electricity (usually produced from coal or gas) dominates the consumption end. The oil-intensive modern food system that evolved when oil was cheap will not survive as it is now structured with higher energy prices. Among the principal adjustments will be more local food production and movement down the food chain as consumers react to rising food prices by buying fewer high-cost livestock products.
16. Danielle Murray, “Oil and Food: A Rising Security Challenge,” Eco-Economy Update (Washington, DC: Earth Policy Institute, 9 May 2005), p. 2 and data charts; irrigation data sources include U.S.
Department of Agriculture (USDA), “Chapter 5: Energy Use in Agriculture,” U.S. Agriculture and Forestry Greenhouse Gas Inventory: 1990–2001, Technical Bulletin No. 1907 (Washington, DC: Global Change Program Office, Office of the Chief Economist, 2004), p. 94.
17. James Duffield, USDA, e-mail to Danielle Murray, Earth Policy Institute, 31 March 2005; USDA, Production, Supply & Distribution, electronic database, at www.fas.usda.gov/psd, updated 13 September 2005.
18. Conservation Technology Information Center (CTIC), “Conservation Tillage and Other Tillage Types in the United States—1990–2004,” 2004 National Crop Residue Management Survey (West Lafayette,
IN: Purdue University, 2004); CTIC, “Top Ten Benefits of Conservation Tillage,” at www.ctic.purdue.edu/Core4/CT/CTSurvey/10Benefits.html, viewed 27 July 2005; Rolf Derpsch, “Extent of No-Tillage Adoption Worldwide,” to be presented at the III World Congress on Conservation Agriculture, Nairobi, Kenya, 3–7 October 2005, e-mail to Danielle Murray, Earth Policy Institute, 9 August 2005.
19. Duffield, op. cit. note 17; tractor use and horse stocks from U.N. Food and Agriculture Organization (FAO), FAOSTAT Statistics Database, at apps.fao.org, updated 4 April 2005.
20. Fertilizer energy use data from Duffield, op. cit. note 17; DOE, EIA, Annual Energy Outlook 2003 (Washington, DC: 2004); John Miranowski, “Energy Demand and Capacity to Adjust in U.S.
Agricultural Production,” presentation at Agricultural Outlook Forum 2005, Arlington, VA, 24 February 2005; fertilizer-to-grain ratios from USDA, op. cit. note 17; Patrick Heffer, Short Term Prospects for World Agriculture and Fertilizer Demand 2003/04–2004/05 (Paris: International Fertilizer Industry Association (IFA), 2005); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: 2001).
21. U.S. grain production data from USDA, op. cit. note 17.
22. Brian Halweil, Eat Here (New York: W.W. Norton & Company, 2004), p. 29; USDA, op. cit. note 17.
23. Compiled by Earth Policy Institute from Duffield, op. cit. note 17; DOE, EIA, op. cit. note 20; USDA, National Agricultural Statistics Service, “Table 20: Energy Expenses for On-Farm Pumping of Irrigation Water by Water Source and Type of Energy: 2003 and 1998,” 2003 Farm & Ranch Irrigation Survey, Census of Agriculture (Washington, DC: 2004); irrigation and land use data from FAO, op. cit. note 19.
24. Data for 1950 from Sandra Postel, “Water for Food Production: Will There Be Enough in 2025?” BioScience, August 1998; irrigation and land use data from FAO, op. cit. note 19; Mark Rosengrant, Ximing Cai, and Sarah Cline, World Water and Food to 2025: Dealing with Scarcity (Washington, DC, and Battaramulla, Sri Lanka: International Food Policy Research Institute and International Water Management Institute, 2002), p. 155.
25. Murray, op. cit. note 16.
26. Ibid., p. 3; M. Heller and G. Keoleian, Life-Cycle Based Sustainability Indicators for Assessment of the U.S. Food System (Ann Arbor, MI: Center for Sustainable Systems, University of Michigan, 2000), p. 42.
27. Halweil, op. cit. note 22, p. 37; Stacy Davis and Susan Diegel, “Chapter 2: Energy,” Transportation Energy Data Book: 24th Edition (Washington, DC: DOE, Energy Efficiency and Renewable Energy, 2004), pp. 2–17; DOE, EIA, “Chapter 5: Transportation Sector,” Measuring Energy Efficiency in the United States Economy: A Beginning (Washington, DC: 1995), p. 31; U.S. Department of Transportation, Bureau of Transportation Statistics (BTS), Freight Shipments in America (Washington, DC: 2004), pp. 9–10; Andy Jones, Eating Oil—Food in a Changing Climate (London: Sustain and Elm Farm Research Centre, 2001), p. 2 of summary.
28. Jones, op. cit. note 27, pp. 1–2 of summary; Charlie Pye-Smith, “The Long Haul,” Race to the Top Web site, www.racetothetop.org/ case/case4.htm (London: International Institute for Environment and Development, 25 July 2002).
29. BTS and U.S. Census Bureau, “Table 14. Shipment Characteristics by Three-Digit Commodity and Mode of Transportation: 2002,” 2002 Commodity Flow Survey (Washington, DC: December 2004); Jones, op. cit. note 27; James Howard Kunstler, author of Geography of Nowhere, in The End of Suburbia: Oil Depletion and the Collapse of The American Dream, documentary film (Toronto, ON: The Electric Wallpaper Co., 2004).
30. Heller and Keoleian, op. cit. note 26, p. 42; food energy content and packaging content calculated by Danielle Murray, Earth Policy Institute, using USDA nutritional information and packaging energy costs from David Pimentel and Marcia Pimentel, Food, Energy and Society (Boulder, CO: University Press of Colorado, 1996), cited in Manuel Fuentes, “Alternative Energy Report,” Oxford Brookes University and the Millennium Debate, 1997; Leo Horrigan, Robert S. Lawrence, and Polly Walker, “How Sustainable Agriculture Can Address the Environmental and Human Health Harms of Industrial Agriculture,” Environmental Health Perspectives, vol. 110, no. 5 (May 2002), p. 448.
31. Murray, op. cit. note 16, pp. 1, 3; Duffield, op. cit. note 17; DOE, EIA, op. cit. note 20; USDA, op. cit. note 23; Miranowski, op. cit. note 20, p. 11.
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