"Urban transport systems based on a combination of rail lines, bus lines, bicycle pathways, and pedestrian walkways offer the best of all possible worlds in providing mobility, low-cost transportation, and a healthy urban environment." –Lester R. Brown, Plan B 4.0: Mobilizing to Save Civilization.
Chapter 2. Deteriorating Oil and Food Security: The Changing Food Prospect
The world grain harvest has more than tripled since 1950, climbing from 630 million to 2 billion tons. The most rapid growth came between 1950 and 1973, when the grain harvest doubled. In 23 years, farmers expanded the grain harvest by as much as during the 11,000 preceding years, from the beginning of agriculture until 1950. 37
The mid-twentieth century marked an abrupt transition point in world agriculture as the frontiers of agricultural settlement largely disappeared. Prior to then, increases in the harvest came largely from expanding the cropped area, as farmers moved from valley to valley and eventually from continent to continent. Yield increases were typically so slow as to be imperceptible within a human life span. In contrast, since 1950 four fifths of the world grain harvest growth has come from raising land productivity, with much of the rise dependent on oil. 38
Between 1950 and 1990, the systematic application of science to agriculture helped raise grain yields from less than 1.1 tons per hectare to close to 2.5 tons. Grainland productivity worldwide increased 2.1 percent a year. Since 1990, however, the rise has slowed to 1.2 percent a year. By 1990, most of the easy steps to raise grain yields had already been taken. 39
The growth in land productivity since 1950 was driven by three trends: a near-tripling of the world irrigated area, a 10-fold growth in world fertilizer use, and the rapid dissemination of high-yielding varieties that centered on hybrid corn in the United States and the high-yielding dwarf wheats and rices in Asia. 40
While world grain production has expanded continuously, it has slowed in recent decades, falling below the growth in world population after 1984. As a result, grain production per person peaked in 1984 at 342 kilograms, dropping to 302 kilograms in 2006. A 12-percent drop in the grain harvested per person could be expected to lead to a dramatic increase in world hunger, but it did not. The number of hungry people in the world, which was greatly reduced from 1950 to 1984, continued to decline until the late 1990s before turning upward. 41
The fall in grain production per person did not automatically translate into more hunger because of the enormous growth in the world soybean harvest—from 68 million tons in 1984 to 222 million tons in 2007. The growing use of soybean meal, the high-protein meal left after the oil is extracted, as a supplement to grain in livestock, poultry, and fish rations both substituted for some of the grain used for feed and greatly increased the efficiency with which the grain itself was converted into animal protein. Feed rations containing roughly four fifths grain and one fifth soybean meal are now standard fare in livestock, poultry, and fish feeding. This allowed the global diet to improve even as the grain supply per person was declining. 42
Originally domesticated by farmers in central China some 5,000 years ago, the soybean now occupies a dominant position in world agriculture. The growth in soybean production has been meteoric. In both Brazil and Argentina, soybean production took off after 1980. By 2005 the soybean harvest in each country was rivaling or exceeding the grain harvest. By 1990, more U.S. land was planted to soybeans than to wheat. 43
In the end, however, the world food prospect depends heavily on the expansion of the “big three” grains—wheat, rice, and corn. In seven of the last eight years, world grain production has fallen short of consumption, dropping world carryover stocks of grain to their lowest level in 34 years. The world’s farmers—already struggling to expand fast enough to feed 70 million more people each year and to allow billions of low-income consumers to move up the food chain—are now being further challenged by the exploding demand for grain to produce fuel ethanol for cars. 44
Farmers are facing new constraints as they attempt to meet record growth in the demand for grain. While the irrigated area was growing throughout the last half-century, supplies of irrigation water in this new century are beginning to shrink in some countries as wells go dry and scarce water is diverted to cities. And for the first time, harvests in large countries like China are being reduced by water shortages. This is most evident with wheat, produced mainly in the more arid northern half of China, where water tables are falling and wells are going dry. China’s wheat harvest peaked in 1997 at 123 million tons and has now dropped to scarcely 100 million tons, a fall of nearly 20 percent. 45
The wildcard in the food prospect is climate change. Crop ecologists estimate that for each 1-degree-Celsius rise in temperature above the norm during the growing season, we can expect a 10-percent decline in grain yields. With higher global temperatures, we can expect more extreme weather events, including more-destructive floods and more-intense droughts. 46
Putting further pressure on farmers is the conversion of cropland to nonfarm uses. This is gaining momentum in many parts of the world, particularly in countries with urban sprawl, such as the United States, and in densely populated, rapidly industrializing countries like China. From the central valley of California to the Yangtze River basin in China, construction of homes, factories, roads, highways, and parking lots is devouring some of the world’s most productive farmland.
37. 1950–59 data from Worldwatch Institute, Signposts 2001, CD-Rom (Washington, DC: 2001); 1960–2006 data from USDA, Production, Supply and Distribution, op. cit. note 6.
38. 1950–59 grain data from Worldwatch Institute, op. cit. note 37; 1960–2006 data from USDA, Production, Supply and Distribution, op. cit. note 6.
39. Worldwatch Institute, Signposts 2002, CD-Rom (Washington, DC: 2002); USDA, Production, Supply and Distribution, op. cit. note 6.
40. Lester R. Brown, Outgrowing the Earth (New York: W. W. Norton & Company, 2004), pp. 60–69.
41. USDA, Production, Supply and Distribution, op. cit. note 6; U. N. Population Division, World Population Prospects, op. cit. note 2; FAO, FAOSTAT Food Security, electronic database, at www.fao.org/faostat, updated 30 June 2006.
42. USDA, Production, Supply and Distribution, op. cit. note 6; Brown, op. cit. note 40, p. 50.
43. USDA, Production, Supply and Distribution, op. cit. note 6; Kelly Day Rubenstein et al., Crop Genetic Resources: An Economic Appraisal (Washington, DC: USDA Economic Research Service, May 2005), p. 19.
44. USDA, Production, Supply and Distribution, op. cit. note 6; U.N. Population Division, World Population Prospects, op. cit. note 2.
45. USDA, Production, Supply and Distribution, op. cit. note 6; U.N. Population Division, World Population Prospects, op. cit. note 2; Michael Ma, “Northern Cities Sinking as Water Table Falls,” South China Morning Post, 11 August 2001; share of China’s grain harvest from the North China Plain based on Hong Yang and Alexander Zehnder, “China’s Regional Water Scarcity and Implications for Grain Supply and Trade,” Environment and Planning A, vol. 33 (2001), and on USDA, Production, Supply and Distribution, op. cit. note 6.
46. Shaobing Peng et al., “Rice Yields Decline with Higher Night Temperature from Global Warming,” Proceedings of the National Academy of Sciences, 6 July 2004, pp. 9971–75; Intergovernmental Panel on Climate Change, Summary for Policymakers in Climate Change 2007: Impacts, Adaptation, and Vulnerability (New York: Cambridge University Press, 2007), pp. 15–16.
Copyright © 2008 Earth Policy Institute