1. The use of field artillery to destroy buildings along Van Ness Avenue is not widely noted in histories of the great San Francisco fire, even in the U.S. Army’s documentation of its role in the disaster. In the fire’s aftermath, great controversy surrounded the decision to destroy buildings to create firebreaks. For this reason, the use of artillery was likely downplayed. The army’s report on the dynamiting of buildings was prepared by Captain Le Vert Coleman, and is available from the San Francisco Museum at http://www.sfmuseum.org/1906/coleman.html. The account of the great San Francisco fire in these paragraphs is drawn largely from reports in The New York Times on April 19, 20, and 21, 1906, especially “Bombardment a Mile Long Fails to Save San Francisco: Mansions Wrecked by Cannon in Last Stand on Nob Hill,” New York Times, April 20, 1906, 1. For a fascinating recent treatment of the quake and fire, see Simon Winchester, A Crack in the Edge of the World: America and the Great California Earthquake of 1906 (New York: HarperCollins, 2005), especially, which explains how the quake caused the fire.
2. Rome’s ruins have inspired literature, art, and scholarly investigation for millennia. Perhaps most famously, Edward Gibbon said he was prompted to write his monumental history on October 15, 1764, as he “sat musing amidst the ruins of the Capitol, while the barefooted fryars were singing Vespers in the temple of Jupiter.” Unfortunately, modern scholars aren’t sure exactly where Gibbon was sitting at the time; there were no visible ruins of the Temple of Jupiter’s superstructure in the eighteenth century. Gibbon’s remark from his autobiography is quoted in David Womersley’s introduction to Edward Gibbon, The History of the Decline and Fall of the Roman Empire, edited and abridged by David Womersley (London: Penguin, 2000 [1776]), xvi.
3. See Joseph Tainter, “Post-Collapse Societies,” Companion Encyclopedia of Archaeology, Graeme Barker, ed. (London: Routledge, 1999), 988–1039. As we will see later in this book, there’s scholarly controversy about the extent to which one can say the Roman empire “fell,” “declined,” or “collapsed,” and also about whether people’s average standards of living fell.
1. James Burke writes marvelously about urban dwellers’ dependence on technologies that they don’t comprehend, their vulnerability to failure of these technologies, and the implications of a mass exodus from cities in the event of such failure. See Burke, Connections (Boston: Little, Brown, 1978), 4–7.
2. A survey article that provides a somewhat similar breakdown of stresses is Robert Kates and Thomas Parris, “Long-term Trends and a Sustainability Transition,” Proceedings of the National Academy of Sciences 100, no. 14 (July 8, 2003): 8062–67.
3. Harvard University’s John Holdren, a physicist and environmental scientist, notes, “Civilization remains dependent on nature, for most of the cycling of nutrients on which food production depends, for most of the regulation of crop pests and agents and vectors of human disease, for most of the detoxification and disposal of wastes, and for the maintenance of climate conditions within limits conducive to all these other environmental services and to the human enterprise more generally.” Holdren, “Environmental Change and the Human Condition,” Bulletin of the American Academy of Arts and Sciences 57, no. 1 (Fall 2003): 25.
4. Two good examples of such arguments are Jack Hollander, The Real Environmental Crisis: Why Poverty, Not Affluence, Is the Environment’s Number One Enemy (Berkeley: University of California Press, 2003); and Peter Huber, Hard Green: Saving the Environment from Environmentalists, a Conservative Manifesto (New York: Basic, 1999).
5. For a discussion of these constraints, see Thomas Homer-Dixon, The Ingenuity Gap: Facing the Economic, Environment, and Other Challenges of an Increasingly Complex and Unforgettable World (New York: Vintage, 2002).
6. Jared Diamond, “The Last Americans,” Harper’s Magazine (June 2003): 45.
7. Eric Hobsbawm, Age of Extremes: The Short Twentieth Century, 1914–1991 (London: Abacus, 1994), 15.
8. Christopher Chase-Dunn, Yukio Kawano, and Benjamin Brewer, “Trade Globalization Since 1795: Waves of Integration in the World-System,” American Sociological Review 65 (February 2000): 77–95.
9. In his autobiography, the Manhattan Project physicist Luis Alvarez writes, “With modern weapons-grade uranium, the background neutron rate is so low that terrorists, if they had such material, would have a good chance of setting off a high-yield explosion simply by dropping one half of the material onto the other half…. Even a high school kid could make a bomb in short order.” Alvarez, Alvarez: Adventures of a Physicist (New York: Basic Books, 1987), 125.
10. In the 1970s, the Italian electrical engineer and futurist Roberto Vacca presented an argument about breakdown in complex systems that’s similar in some respects to the one offered in these pages, especially in its focus on interactions between stresses and the possibility of “coincident breakdown.” According to Vacca, systems break down when their complexity and congestion exceed managers’ control. Although his argument doesn’t reflect recent research on self-organizing complex systems, it still bears close attention. Vacca has developed considerable renown for his ability to predict system failures, including the collapse of the Soviet Union. See Vacca, The Coming Dark Age: What Will Happen When Modern Technology Breaks Down, trans. J. S. Whale (Garden City, NY: Anchor, 1974).
11. James Howard Kunstler makes an argument along these lines in The Long Emergency: Surviving the Converging Catastrophes of the Twenty-First Century (New York: Atlantic Monthly Press, 2005).
12. Jack Goldstone, Revolution and Rebellion in the Early Modern World (Berkeley: University of California Press, 1991).
13. This is especially true because such events might not be independent of each other: in some circumstances, the occurrence of one kind of shock could boost the likelihood of others.
14. For instance, the American writer Gregg Easterbrook contends that concerns about the rising likelihood of social breakdown are simply a product of “collapse anxiety”—a generalized fear in rich countries that high standards of living can’t be sustained. He thus manages to disparage such concerns by labeling them a psy-chopathology, without really explaining their source. See Easterbrook, The Progress Paradox: How Life Gets Better While People Feel Worse (New York: Random House, 2003).
15. Some thoughtful people have reached similar conclusions about our future. See, for example, Martin Rees, Our Final Hour: A Scientist’s Warning: How Terror, Error, and Environmental Disaster Threaten Humankind’s Future in This Century—On Earth and Beyond (New York: Basic, 2003); Robert Harvey, Global Disorder: How to Avoid a Fourth World War (New York: Carroll & Graf, 2003); Jared Diamond, Collapse: How Societies Choose to Fail or Succeed (New York: Viking, 2005); and Didier Sornette,“2050: The End of the Growth Era,” chapter 10 in Why Stock Markets Crash: Critical Events in Complex Financial Systems (Princeton: Princeton University Press, 2003).
16. In statistical terms, catastrophic events lie in the tail of a “power-law frequency distribution.” This means they’re very rare but not impossible. As we’ll see in chapter 5, the same is true of highly connected hubs in scale-free networks. Richard Posner uses cost-benefit analysis (technically, expected value calculations) to argue that it makes economic sense to invest in preventing rare, large-scale catastrophes. See Posner, Catastrophe: Risk and Response (New York: Oxford, 2005).
17. Amory Lovins and Hunter Lovins, Brittle Power: Energy Strategy for National Security (Andover, MA: Brick House, 1982), 1.
18. Amory Lovins, correspondence with the author, July 23, 2002. Permission granted for quotation.
19. The word catagenesis is also used in petroleum geology: categenesis happens when organic compounds are “cracked” or broken down into oil under conditions of high pressure and temperature deep underground.
20. For a thorough survey of the history of systems thinking, see Charles François, “Systemics and Cybernetics in a Historical Perspective,” Systems Research and Behavioral Science, Syst. Res. 16 (1999): 203–19.
21. We’ll learn in chapter 2 that complex adaptive systems are orderly, thermodynamically open, and far from thermodynamic equilibrium, that their parts are diverse and specialized, and that they exhibit self-organization. In chapter 5, we’ll learn that the parts of complex systems are often connected together in dense, scale-free networks that produce feedbacks and synergies. A serviceable indicator of a system’s complexity is its “algorithmic complexity,” which is the length of a computer program, or algorithm, that can reproduce the system’s behavior (the longer the algorithm, the more complex the system). On measures of complexity, see Homer-Dixon, The Ingenuity Gap, 115–16.
22. A good overview of this research is C. S. Holling, “Understanding the Complexity of Economic, Ecological, and Social Systems,” Ecosystems 4 (2001): 390–405. See also Lance Gunderson and C. S. Holling, Panarchy: Understanding Transformations in Human and Natural Systems (Washington, DC: Island Press, 2002).
23. The notion of constrained breakdown may seem odd because most of us assume that breakdown has to be—almost by definition—sudden, thoroughgoing, and catastrophic. But in reality there are lots of gradations along a continuum between catastrophic collapse at one extreme and straight-line stability at the other.
24. When small changes produce very large effects, specialists say the system is “sensitive to initial conditions.” Such sensitivity is a key feature of systems that exhibit chaotic behavior.
25. Figures from the Internet Systems Consortium, available at http://www.isc.org/ index.pl?/ops/ds/.
26. Henry Mintzberg surveys the dismal record of our best forecasters in “The Performance of Forecasting,” in The Rise and Fall of Strategic Planning: Reconceiving Roles for Planning, Plans, and Planners (New York: Free Press, 1994), 228–30.
27. An informative attempt at long-range forecasting is the State of the Future project of the Millennium Project of the American Council for the United Nations University. This project produces annual reports that are among the best efforts at synthesizing large amounts of data and expert opinion on humankind’s future. Once again, though, forecasts tend to be straight-line extrapolations of current trends. Further information is available at http://www.acunu.org.
28. James William Sullivan, “The Future Is a Fancyland Palace,” in Dave Walter, ed., Today Then: America’s Best Minds Look 100 Years into the Future on the Occasion of the 1893 World’s Columbian Exposition (Helena, MT: American & World Geographic Publishing, 1992), 27.
1. The architectural historian Frank Sear writes, “[The voussoir arch] was not a Roman invention. Probably of eastern origin, it was making a tentative appearance in Hellenistic and Etruscan architecture by the fourth century.” According to Jean-Pierre Adam, “It can be established that the technique of the true arch arrived in the Italian peninsula gradually and that the Greeks and the Etruscans, more advanced in the art of stone-work, worked out the first models known to the Romans.” See Sear, Roman Architecture, revised edition (London: B. T. Batsford, 1989), 17–18; and Adam, Roman Building: Materials and Techniques, trans. Anthony Mathews (London: Routledge, 2001), 158–63.
2. Travertine has a density of about 2.7 grams per cubic centimeter, giving a mass of 2.7 metric tons per cubic meter. I estimated that the keystone in question was about 2.1 cubic meters in volume, giving a total mass of 5.7 metric tons.
3. Rabun Taylor, Roman Builders: A Study in Architectural Process (Cambridge: Cambridge University Press, 2003), 135.
4. Ibid., 8, 134.
5. Stone clamps were made of forged iron; after their insertion, molten lead was poured in the void around them to fix them in place and deter rusting.
6. The data and calculations for stone, concrete, and brick can be found at www.theupsideofdown.com/rome/colosseum. The figure for the number of tons of marble was taken from John Pearson, Arena: The Story of the Colosseum (London: Thames and Hudson, 1973), 84, and that for the quantity of metal from Sear, Roman Architecture, 138.
7. Joseph Tainter, subsection II, “Energy Basis of Ancient Societies,” in “Sociopolitical Collapse, Energy and,” Encyclopedia of Energy, Cutler Cleveland, ed. (San Diego: Academic Press/Elsevier Science, 2004), 529–43.
8. “The history of human culture can be viewed as the progressive development of new energy sources and their associated conversion technologies.” Charles Hall et al., “Hydrocarbons and the Evolution of Human Culture,” Nature 426, no. 6964 (November 20, 2003): 318–22. See also Alfred Crosby, Children of the Sun: A History of Humanity’s Unappeasable Appetite for Energy (New York: Norton, 2006).
9. M. S. Spurr, Arable Cultivation in Roman Italy: c. 200 B.C.-c. A.D. 100 (London: Society for the Promotion of Roman Studies, 1986), 1–16.
10. Ian Graham and Joseph Tainter generously contributed to the ideas and text in the following paragraphs. The Swedish human ecologist Alf Hornborg develops an argument similar to the argument in this subsection in The Power of the Machine: Global Inequalities of Economy, Technology, and Environment (Walnut Creek, CA: AltaMira Press, 2001).
11. An early statement of this argument can be found in Leslie White, The Science of Culture: A Study of Man and Civilization (New York: Farrar, Straus and Giroux, 1949 [1969]), especially chapter 13, “Energy and the Evolution of Culture,” 363–93, in particular 367.
12. There is a vast amount of heat energy in the ground—heat that has been absorbed from the sun above or that has percolated from Earth’s core below—but we can’t use it to power our cars or light our streets. We can use it to heat our buildings, but we first need a high-quality form of energy, like electricity, to drive a heat pump (basically a refrigerator operating in reverse) to concentrate the ground’s diffuse heat into useful building heat.
13. There are at least three independent concepts of energy quality. First, and perhaps most fundamental, is energy quality in terms of capacity to do work—or what physicists call “exergy”—as measured by some thermodynamic indicator like Gibbs free energy. Energy quality, by this conception, depends in part on physical context, especially the boundary conditions between two systems. For instance, the amount of work that can be done by energy flowing from a heat source to a heat sink is proportional to the temperature difference between the two systems. A second concept is energy quality in terms of energy density, as defined by a measure like calories/unit of mass or calories/unit of volume. And third is energy quality in terms of usability of the energy resource, which is a function of human technology. Oil wasn’t a high-quality energy resource until human beings developed the technologies to exploit it. This tripartite distinction means that we can have a degradation of energy quality in a system in thermodynamic terms, while energy quality in parts of the system nevertheless increases in terms of density and usability. For discussions of energy quality, see Charles Hall, Cutler Cleveland, and Robert Kauffman, Energy and Resource Quality: The Ecology of the Economic Process (Niwot, Colorado: University Press of Colorado, 1992); Howard Odum, Environment, Power, and Society (New York: Wiley-Interscience, 1971); and Joseph Tainter et al., “Resource Transitions and Energy Gain: Contexts of Organization,” Conservation Ecology 7, no. 3 (2003), available at www.ecologyandsociety.org/v0l7/iss3/art4/print.pdf.
14. This first law of thermodynamics is a special case of the more general principle of the interchangeability of matter and energy stated by Albert Einstein in his special theory of relativity, E = mc2.
15. I’m assuming here that the physical processes in question are not “reversible,” which is almost always true. In special circumstances, however, some processes are reversible: for instance, chemical reactions, if run slowly enough, can be reversible, and some coherent quantum-mechanical processes like tunneling and superconductivity are reversible. In these cases, entropy stays constant. See Seth Lloyd, “Going into Reverse,” Nature 430, no. 7003 (August 26, 2004): 971.
16. Bruce Frier, “Demography,” chapter 27 in Alan Bowman, Peter Garnsey, and Dominic Rathbone, The Cambridge Ancient History, Second Edition, Vol. XI, The High Empire, A.D. 70–192 (Cambridge: Cambridge University Press, 2000), 787–816, especially 793.
17. A classic discussion is Ludwig von Bertalanffy, “An Outline of General System Theory,” British Journal for the Philosophy of Science 1, no. 2 (August 1950): 134–165, especially 162. Bertalanffy distinguishes between “catamorphosis” (the inevitable degradation of inorganic matter) and “anamorphosis” (the spontaneous creation of complexity and diversity in living nature).
18. The relatively new branch of physics of non-equilibrium thermodynamics studies how orderly, complex, and self-organizing systems are possible. Classical thermodynamics assumes that things happen slowly and that the flow of energy in and out of a system is very small relative to the energy inside the system itself. The system is in equilibrium with its surrounding environment, which means, in simplest terms, that it has the same temperature as that environment. But non-equilibrium systems like steel mills, societies, or ecosystems take in and expel vast amounts of energy and have a much higher temperature than their surroundings. Physicists call such systems “dissipative structures” because the energy that sustains them is dissipated to waste heat. The great theoretical physicist Erwin Schrödinger pioneered non-equilibrium thermodynamics. For a lay account, see his book, What Is Life? (Cambridge: Cambridge University Press, 1944), especially chapter 6, “Order, Disorder and Entropy,” 72–80. For more technical details, see Grégoire and Ilya Prigogine, Self-Organization in Nonequilibrium Systems (New York: John Wiley and Sons, 1977). The field of non-equilibrium thermodynamics remains contentious, and some scientists argue it explains little. For a skeptical review, see Philip Anderson and Daniel Stein, “Broken Symmetry, Emergent Properties, Dissipative Structures, Life: Are They Related?” in F. Eugene Yates, ed., Self-Organizing Systems: The Emergence of Order (New York: Plenum Press, 1987), 445–57. In contrast, Eric Schneider and James Kay argue that self-organization functions to increase the rate of energy degradation, which in turn helps move the overall system back toward thermodynamic equilibrium. “No longer is the emergence of coherent self-organizing structures a surprise, but rather it is an expected response of the system as it attempts to resist and dissipate externally applied [energy] gradients which would move the system away from equilibrium.” See their article, “Complexity and Thermodynamics: Towards a New Ecology,” Futures 26, no. 6 (1994): 626–47.
19. For a fascinating account of the emergence of an early form of the corporation in the form of societas publicanorum or “society of publicans,” see Ulrike Malmendier, “Roman Shares,” in William Goetzmann and K. Geert Rouwenhorst, eds., The Origins of Value: The Financial Innovations That Created Modern Capital Markets (Oxford: Oxford University Press, 2005), 31–42.
20. “Many once-proud ancient cultures have collapsed, in part, because of their inability to maintain energy resources and societal complexity.” Hall et al., “Hydrocarbons.”
21. Further details on these calculations can be found at www.theupsideofdown.com/rome/colosseum.
22. Similarly, the lime used in concrete was slaked in wood-fired kilns.
23. Jean-Pierre Adam provides a wonderfully detailed and illustrated account of Roman techniques for cutting rock in “Materials,” chapter 2 of Roman Building, 22–40.
24. Sear, Roman Architecture, 139. It has also been estimated that 292,000 cartloads were required to transport the materials to build the Colosseum. Over five years, assuming 220 working days a year, this translates into about 265 cartloads for each working day. See William MacDonald, The Architecture of the Roman Empire: I. An Introductory Study (London: Yale University Press, 1965), 148; and Pearson, Arena, 84.
25. Janet DeLaine points out that Roman “concrete” was really mortared rubble construction. The Romans didn’t combine mortar with aggregate and then pour the mixture into forms, as do modern builders. Instead they built walls, for instance, by first using mortar and something like brick to make the two faces of the wall; after the faces dried to create a permanent form, they then laid between them “alternate layers of rubble and a stiff mortar” to form the wall’s core. See DeLaine, “Bricks and Mortar: Exploring the Economics of Building Techniques at Rome and Ostia,” chapter 11 in David Mattingly and John Salmon, eds., Economies beyond Agriculture in the Classical World (London: Routledge, 2001), 230–68.
26. Adam, Roman Building, 174–77.
27. On Roman cranes in general, see Adam, Roman Builders, 43–48.
28. Ibid., 43.
29. Taylor, Roman Builders, 170–72.
30. Karen broke down the building’s three-dimensional volume into smaller geometric forms, like cubes, cylinders, sections of cones, and three-dimensional ellipses. The pillars of the arch containing my keystone, for example, were two rectangular cubes standing on end, while the arch itself was another rectangular cube laid across the top of the pillars with a cross-sectional slice of a cylinder subtracted to account for the arch’s open space. Then, by calculating the volume of each of these geometric objects and multiplying the volume by travertine’s mass per cubic meter, she estimated the arch’s total mass. Finally, by adding up the mass of all the building’s components made of the same material, she produced an estimate of the Colosseum’s total mass of travertine.
31. To keep a steady stream of materials coming into the Colosseum, we assumed that two oxen were on the road to the Colosseum for every ox making the return journey to the quarry.
32. Pearson, Arena, 85. On the guilds involved in Roman construction in general, see MacDonald, The Architecture of the Roman Empire, 144.
33. We based these calculations on detailed estimates of the labor requirements in Roman construction developed by the Oxford scholar of Roman engineering Janet DeLaine. See DeLaine, The Baths of Caracalla: A Study in the Design, Construction, and Economics of Large-scale Building Projects in Imperial Rome (Portsmouth, RI: Journal of Roman Archaeology, Supplementary Series no. 25, 1997).
34. On the number of fountains, see Taylor, Roman Building, 143–44.
35. The standard unit of human energy consumption is the kilocalorie, which is sometimes called the Calorie (in upper case) by human nutrition specialists. The kilocalorie corresponds to 1,000 calories (in lower case), where a calorie is the amount of heat required to raise one gram of water one degree Celsius. Dieters commonly talk about calories, and so do just about all media commentators on dieting and human health, but they’re really referring to kilocalories (or Calories).
36. A number of important assumptions are implicit in these figures. For instance, we assumed that the resting caloric consumption, which specialists call “the basal metabolic rate,” is 1,694 kilocalories a day for human beings and 6,261 kilocalories a day for oxen, while the heavy-work caloric consumption is 3,015 kilocalories for human beings and 11,144 kilocalories for oxen. We also assumed frictional coefficients of 0.1 for cart transport offsite and 0.3 for sliding of materials on site; an efficiency of conversion of calories to work of 40 percent for both humans and oxen; and a general inefficiency factor of 50 percent for all hoisting and sliding by laborers. To ascertain the robustness of our conclusions in the event of changes in some of these assumptions, we conducted a sensitivity analysis that varied both the inefficiency factor and frictional coefficients. For further details, see www.theupsideofdown.com/rome/colosseum. Calculations of basal metabolic rate and adjustments for activity level are based on Vaclav Smil, Feeding the World: A Challenge for the Twenty-First Century (Cambridge, MA: MIT Press, 2000), 149, 215–23.
37. Scholars generally believe that the complex of chambers and passageways under the arena’s floor was added after the building’s initial construction, probably by Emperor Domitian, Vespasian’s younger son.
38. “Wheat was the staple diet of the vast majority of the people, and far and away the largest item in their food bill.” A. H. M. Jones, The Roman Economy: Studies in Ancient Economic and Administrative History, P. A. Brunt ed. (Totawa, NJ: Rowman and Littlefield, 1974), 192.
39. See M. P. Cato, chapter 54 of Cato, The Censor, On Farming [De agricultura], trans. Ernest Brehaut (New York: Octagon Books, 1966), 77–78.
40. The value of alfalfa as fodder in Roman times is discussed in Michael Russelle, “Alfalfa,” American Scientist 89, no. 3 (May-June 2001): 252, available at www.americanscientist.org/template/AssetDetail/assetid/14349/page/1;jsessionid=aaa94U-2fac3-m.
41. See M. P. Cato, chapter 54, On Farming [De agricultura], in Roman Farm Management: The Treatises of Cato and Varro done into English, with Notes of Modern Instances by a Virginia Farmer, trans. and ed. Fairfax Harrison (New York: MacMillan, 1918), 45.
42. Geoffrey Rickman, chapter 5, “The Corn Lands,” in The Corn Supply of Ancient Rome (Oxford: Clarendon Press, 1980), 94–119; and Greg Aldrete and David J. Mattingly, “Feeding the City: The Organization, Operation, and Scale of the Supply System for Rome,” in D. S. Potter and D. J. Mattingly, eds., Life, Death, and Entertainment in the Roman Empire (Ann Arbor: University of Michigan Press, 1999), 171–204. See also Emin Tengström, Bread for the People: Studies of the Corn-Supply of Rome during the Late Empire (Stockholm: Paul Aströms Förlag, 1974).
43. Despite Rome’s outstanding road system, overland transport of grain was prohibitively expensive. The Roman historian A. H. M. Jones writes, “Wheat seems in fact rarely or never to have been transported any distance by land, except by the imperial government, which did not have to count the cost.” According to Michael Fulford, however, archaeological evidence indicates there were substantial shipments of grain by sea around the Mediterranean basin, and not just to the city of Rome. See Fulford, “Economic Interdependence among Urban Communities of the Roman Mediterranean,” World Archaeology 19 (1987): 58–75; and Jones, The Roman Economy, 37. On the role of Etruria, Campania, and Latium in supplying food to Rome, see Rickman, The Corn Supply of Ancient Rome, 14.
44. A. H. M. Jones, The Later Roman Empire, 284–602: A Social, Economic, and Administrative Survey, Vol. 1 (Baltimore: Johns Hopkins University Press, 1964), 698. Aldrete and Mattingly, “Feeding the City,” 179–84.
45. Jérôme Carcopino, Daily Life in Ancient Rome: The People and the City at the Height of the Empire, edited with bibliography and notes by Henry Rowell and translated by E. O. Lorimer (New Haven: Yale University Press), 18. On the logistics of grain storage, see Rickman, chapter 6, “Transport, Storage, and Prices,” The Corn Supply of Ancient Rome, 120–55.
46. On wheat yields, see M. T. Varro, Book I, Chapter 64 of On Farming (Rerum rusticarum), trans. Lloyd Storr-Best (London: G. Bell and Sons, Ltd., 1912), 92 and the calculations at www.theupsideofdown.com/rome/colosseum. Our estimate of wheat yields, based on Varro, is high compared with some other authors and therefore leads to a conservative estimate of the land needed to build the Colosseum. For instance, Smil provides a figure of 400 kilograms of wheat per hectare, and Jones interprets tax and rent records in Roman Egypt to suggest yields around 1,000 kilograms. See Table A3.9, “Labor Requirements and Energy Costs of European Wheat Harvests, 200–1800,” in Vaclav Smil, Energy in World History (Boulder: Westview, 1994), 89; and Jones, The Roman Economy, 83. On alfalfa yields, see Purdue University, Centre for New Crops and Plants Products, “Medicago sativa L.,” sections on “Energy” and “Yields and Economics,” based on James A. Duke, “Handbook of Energy Crops,” unpublished, 1983, available from http://www.hort.purdue.edu/newcrop/duke_energy/Medicago_sativa.html.
47. Our calculations assumed that 10 percent of the grain produced in any year was held back for seed for the following year’s planting, and 30 percent of the grain produced was lost to spoilage and pests. The estimate of holdback for seed is likely conservative; for instance, during the Middle Ages farmers in Europe usually put aside at least a third of their crop for this purpose. Our spoilage estimate is drawn from Vaclav Smil’s discussion. In modern-day agriculture, Smil writes, cumulative losses—from harvesting and threshing through storage, transport, and milling— range “from well below 10 percent to as much as 40 percent (and even higher figures [have been] reported for some African crops).” See Smil, Feeding the World, 185–86.
48. We estimated that a kilogram of wheat contains 3,420 kilocalories, while a kilogram of dry alfalfa contains 2,557 kilocalories. For the caloric content of wheat, see USDA Agricultural Research Service, Nutrient Data Laboratory. USDA National Nutrient Database for Standard Reference. Release 18, 2006, “Wheat, hard white,” NDB no. 20074, available from http://www.ars.usda.gov/main/ site_main.htm?modecode=12354500. For caloric content of alfalfa hay, see Douglas M. Considine, ed., “Feedstuffs,” Foods and Food Production Encyclopedia (New York: Van Nostrand Reinhold, 1982), 616–63, especially 621.
49. The EROI concept was first introduced in Cutler Cleveland, Robert Costanza, Charles Hall, and Robert Kaufmann, “Energy and the U. S. Economy: A Biophysical Perspective,” Science 255 (1984): 890–97. See also Hall, Cleveland, and Kauffman, Energy and Resource Quality, 27–29. Calculating an EROI raises some difficult issues of aggregation across different qualities of energy. For a discussion, see Cutler Cleveland, “Net Energy from the Extraction of Oil and Gas in the United States,” Energy 30, no. 5 (April 2005): 769–82.
50. Hall, “Hydrocarbons,” 320.
51. Chris Wickham, “The Other Transition: From the Ancient World to Feudalism,” Past and Present 103, (May 1984): 3–36, especially 6.
52. M. S. Spurr, “Arable Cultivation in Roman Italy, c.200B.C.-c. A.D. 100,”Journal of Roman Studies, Monograph no. 3.(London: Society for the Promotion of Roman Studies, 1986): 138–39.
53. The difference in EROIs for wheat and alfalfa partly explains why Romans preferred to use, wherever possible, draft animals like oxen rather than slaves or laborers to work. The EROI figures provided here for wheat are considerably lower than those suggested by other scholars, such as Smil. The latter’s calculations, however, apparently do not include losses due to spoilage and vermin or the need to put aside a portion of the harvest for the subsequent year’s seeding; nor do they take into account the energy cost of keeping laborers alive on off days. See Table A3.9, “Labor Requirements and Energy Costs of European Wheat Harvests, 200–1800,” in Smil, Energy in World History, 89.
54. This estimate is conservative: the actual amount the Romans needed was almost certainly larger. As mentioned earlier in this chapter, a number of things were left out of the calculation of the energy needed to build the Colosseum. Also, the calculation of the amount of grain needed to supply this energy excludes the energy needed to move that grain itself. In a sense, the calculation implicitly assumes that the food grew right next to the construction site. But, in reality, transporting it from Africa, Egypt, Sicily, and Spain—or even from Etruria—would have required a great deal of work. This is, once again, an open system problem: not only did the grain have to be shipped but the shippers had to be fed, as did the people who fed the shippers, and the people who constructed the shippers’ boats and carts, and so on.
55. The details of these calculations can be found at www.theupsideofdown.com/rome/colosseum. The figures in this paragraph incorporate the assumption that at any one time 50 percent of the land had to be left fallow to maintain its fertility. To calculate the farm area needed to carve, move, and place the keystone, we assumed that the food energy for these tasks was generated over one growing season only.
56. Rome was the “most urbanized state of the Western world before modern times.” Roger S. Bagnall and Bruce W. Frier, The Demography of Roman Egypt (Cambridge: Cambridge University Press, 1994), 56.
57. See Lewis Mumford’s marvelous discussion of Rome in “The Natural History of Urbanization,” in William L. Thomas Jr., ed., Man’s Role in Changing the Face of the Earth (Chicago and London: University of Chicago Press, 1956), available at http://habitat.aq.upm.es/boletin/n21/almum.en.html. See also Sander van der Leeuw and Bert de Vries, “Empire: The Romans in the Mediterranean,” chapter 7 in Bert de Vries and Johan Goudsblom, eds., Mappae Mundi: Humans and Their Habitats in a Long-Term Socio-Ecological Perspective: Myths, Maps and Models (Amsterdam: RIVM, Amsterdam University Press, 2002), 209–56.
58. The maximum size of the city’s population is open to dispute. Estimates range from a low of 250,000 to a high of 1.6 million. After a balanced assessment, Carcopino arrives at an estimate in the middle of the range. “The available data,” he writes, “combine to force us to conclude that the inhabitants of Rome must have reached nearly a million.” See Carcopino, Daily Life in Ancient Rome, 10–21, especially 18. Walter Scheidel identifies the consensus estimate: “[A] million is conventionally taken to represent a credible peak value….” See Scheidel, “Progress and Problems in Roman Demography,” in Debating Roman Demography, ed. Walter Scheidel (Leiden: Brill, 2001), 51.
59. For an excellent account of these difficulties, see Pierre Salmon, Population et depopulation dans l’Émpire romain (Brussels: Latomus, Revue d’études Latines, 1974); Salmon lists the most important scholarly estimates of the city of Rome’s population (up to the date of his writing).
60. Bruce Frier, “Demography,” in The Cambridge Ancient History, 813–14. See also Bruce Frier, “Roman Demography,” in Potter and Mattingly, eds., Life, Death, and Entertainment in the Roman Empire, 101.
61. Bagnall and Frier argue that Alexandria (with a population of around half a million, one of the largest cities in the empire after Rome) and the other cities in Egypt together made up an urban population of 1.75 million out of a total provincial population in the neighborhood of 4.75 million, for a rate of urbanization that was approximately 37 percent. Although they acknowledge that the figure seems high, they conclude that a third of Egypt’s population is likely to have lived in cities. Egypt exhibited, they write, “a degree of urbanization … that was high even by the standards of the Roman empire.…” Russell convincingly argues that the population of the Italian peninsula in the time of Augustus was around 7 million. If Rome’s population was around 1 million, and that of each of Italy’s other urban areas totaled around half a million, the region’s level of urbanization would have been over 20 percent. See Bagnall and Frier, The Demography of Roman Egypt, 56; and J. C. Russell, “Late Ancient and Medieval Population,” Transactions of the American Philosophical Society, New Ser., 48, no. 3. (1958): 1–152, specifically 72–73.
62. Walter Scheidel, “Progress and Problems in Roman Demography” in Debating Roman Demography, ed. Walter Scheidel (Leiden: Brill, 2001), 51. Historical demographers Richard Lawton and Robert Lee write, “By 1750 nearly nine million people lived in the 261 European cities of over 10,000 inhabitants. By then one-third was in central European towns, over one-quarter (28.7 per cent) in northern and western Europe and only 35.8 per cent in the Mediterranean: moreover, the percentage of the total population in such towns in these three regions was 7.5, 13.6, and 11.8, respectively, a substantial growth in the urbanized population of north-west and central Europe, but a relative fall in the Mediterranean.” See Lawton and Lee, chapter 1, “Introduction: The Framework of Comparative Urban Population Studies in Western Europe, c. 1750–1920,” in Richard Lawton and Robert Lee, eds. Urban Population Development in Western Europe (Liverpool: Liverpool University Press, 1989), 1.
63. E. A. Wrigley, “Brake or Accelerator? Urban Growth and Population Growth before the Industrial Revolution,” chapter 7 in Ad van der Woude, Akira Hayami, and Jan de Vries, Urbanization in History: A Process of Dynamic Interactions (Oxford: Clarendon Press, 1990), 101–12.
64. Some of the most impressive construction took place in the vicinity of the port of Ostia, at the mouth of the Tiber. Greg Aldrete and David Mattingly write, “About four kilometers north of Ostia, Claudius excavated out of the coastline a gigantic basin over 1,000 meters wide. He also cut canals connecting the new harbor with the Tiber and had two moles [earthworks] built up to shelter the harbor from the sea. Even in this new harbor … ships were still not immune from storms…. The problem of storms was finally solved by Trajan, who excavated a hexagonal inner harbor basin 700 meters in diameter.” Aldrete and Mattingly, “Feeding the City,” 179.
65. “The wheat supply of Rome would necessitate a minimum of 948 shiploads of wheat each year.” The shipping was done by the private sector, though the government offered incentives: “The state did not seek initially to develop its own merchant fleet, relying instead on private shipping agencies to transport the goods to Rome. It is clear, however, that a number of inducements were offered to encourage this trade….” Aldrete and Mattingly, “Feeding the City,” 177, 193. See also Rickman, The Corn Supply of Ancient Rome, 17.
66. Jones, The Roman Economy, 228–56 and 405–406. See also van der Leeuw and de Vries, “Empire: The Romans in the Mediterranean,” 234–36.
67. Jones, The Roman Economy, 83. For a discussion of the importance of the agricultural tax to the empire’s finances, see Jones, The Later Roman Empire, Vol. 1, 464–65.
1. The emperor Antoninus Pius even minted coins embellished with the words felicitas temporum, literally “the happiness of the times.”
2. Edward Luttwak, The Grand Strategy of the Roman Empire: From the First Century A.D. to the Third (Baltimore: Johns Hopkins University Press, 1976), 128–29. See also A. H. M. Jones, The Later Roman Empire, 284–602: A Social, Economic, and Administrative Survey, Vol. 1 (Baltimore: Johns Hopkins University Press, 1964), 14–36.
3. David Whitehouse, “Archaeology and the Pirenne Thesis,” in Charles Redman, ed., Medieval Archaeology: Papers of the Seventeenth Annual Conference of the Center for Medieval and Early Renaissance Studies (Binghamton: State University of New York at Binghamton, 1989), 6–7.
4. Roberto Luciani, Roma Sotterranae (Rome: Fratelli Palombi, 1984), 9; Jérôme Carcopino, Daily Life in Ancient Rome: The People and the City at the Height of the Empire, ed. Henry Rowell, trans. E. O. Lorimer (New Haven: Yale University Press, 1940), 16–21; Whitehouse, “Archaeology and the Pirenne Thesis,” 4–21; and Richard Hodges and David Whitehouse, Mohammed, Charlemagne & the Origins of Europe: Archaeology and the Pirenne Thesis (London: Duckworth, 1983), 51. According to Carcopino, the 1939 census estimated that Rome’s population was almost 1.3 million people, which suggests that Luciani’s estimate of 1 million inhabitants in 1950 is too low.
5. Luciani, Roma Sotterranae, 9–15; and Jones, The Later Roman Empire, 1043.
6. Jones, The Later Roman Empire, 1044.
7. Bruce Frier, “Demography,” chapter 27 in Alan Bowman, Peter Garnsey, and Dominic Rathbone, The Cambridge Ancient History, Second Edition, Vol. XI, The High Empire, A.D. 70–192 (Cambridge: Cambridge University Press, 2000), 787–816, especially 813–15.
8. Jones, The Later Roman Empire, 1040–44.
9. Chris Wickham, Early Medieval Italy: Central Power and Local Society, 400–1000 (Ann Arbor: University of Michigan Press, 1989), 27, 40–41; and Joseph Tainter, “Post-Collapse Societies,” Companion Encyclopedia of Archaeology, Graeme Barker, ed. (London: Routledge, 1999), 988–1039.
10. Frier, “Demography,” 815. For estimates of world population through history, see the summary provided by the U.S. Census Bureau available at http://www.census.gov/ipc/www/worldhis.html.
11. The statistics in this and the following paragraphs were extracted from the United Nations Department of Economic and Social Affairs, Population Division, “World Population Prospects: The 2004 Revision, Highlights” and “Data Online” (New York: United Nations, Department of Economic and Social Affairs, 2005), available at http://www.un.org/esa/population/unpop.htm. See also “Demographic Prospects 2000–2050 According to the 2002 Revision of the United Nations Population Projections,” Population and Development Review 29, no. 1 (March 2003): 139–45.
12. This estimate assumes a world population in 2055 (based on the 2004 UN medium variant) of 9.2 billion.
13. For example, see Ben Wattenberg, Fewer: How the New Demography of Depopulation Will Shape Our Future (Chicago: Ivan R. Dee, 2004); and Nicholas Eberstadt, “The Population Implosion,” Foreign Policy (March/April 2001): 42–53.
14. Branko Milanovic, lead economist at the World Bank, uses Portuguese per capita income—calculated at “purchasing power parity”—to define the threshold at which countries become “rich.” See Milanovic, Worlds Apart: Measuring International and Global Inequality (Princeton: Princeton University Press, 2005), 130–31.
15. On the challenges of low fertility rates, see Peter Peterson, Gray Dawn: How the Coming Age Wave Will Transform America—and the World (New York: Times Books, 1999). Demographers generally assume that a rate of 2.1 births a female ensures the replacement of the mother and her reproductive partner, with allowance (0.1) for the children’s possible mortality before they reach their reproductive years. Recently, however, they have recognized that the true replacement rate is higher in some societies.
16. John Bongaarts, “Demographic Consequences of Declining Fertility,” Science 282, no. 5388 (October 16, 1998): 419–20. In India and China, various forms of sex selection prior to birth, often using ultrasound technologies, have significantly decreased the ratio of girls to boys, reducing the force of the population momentum described here.
17. Paul Demeny, “Population Policy Dilemmas in Europe at the Dawn of the Tventy-First Century,” Population and Development Review 29, no. 1 (March 2003): 4.
18. These countries are, Demeny says, the European Union’s “southern hinterland— a kind of near-abroad to the continent’s western half.” He continues: “The obviously Eurocentric label is justified by the chosen topic of the present discussion. Seen from a different vantage point, the European Union could be described with equal accuracy as the hinterland of North Africa and West Asia.” Ibid., 11. Demeny somewhat arbitrarily excludes from his list Muslim black Africa, also a large source of migration to Europe.
19. The UN’s 2050 population estimate for Europe incorporates a number of key assumptions that have the effect of boosting Europe’s predicted population, so Demeny’s projection of the population imbalance between Europe and its neighbors is highly conservative. Specifically, the UN assumes that European birthrates will increase from the current 1.4 children a woman to 1.82 by 2050, that the average European life expectancy will increase to eighty-three years, and that there will be an influx of 25 million immigrants into Europe in the first half of this century (a number equivalent to more than 40 percent of France’s current population).
20. Demeny, “Population Policy Dilemmas in Europe,” 14.
21. Many analysts use a tripartite distinction between low-, middle-, and high-income countries; such a distinction, however, would not materially affect my argument. See Geoffrey Garrett, “Globalization’s Missing Middle,” Foreign Affairs 83, no. 6 (November-December 2004): 84–97. On the disparity in population growth between rich and poor countries, see Nathan Keyfitz’s review of Alfred Sauvy, L’Europe submergée: Sud ‡ Nord dans 30 ans (Paris: Dunod, 1987), in Population and Development Review 15, no. 2 (1989): 359–62.
22. Norimitsu Onishi, “Out of Africa or Bust, with a Desert to Cross,” New York Times, January 4, 2001, national edition, A1 and A21.
23. Reuters, “241 Illegal Migrants Reach Italian Island in a Fishing Vessel,” New York Times, August 30, 2004, national edition, A7; and Ian Fisher and Richard Bernstein, “On Italian Isle, Migrant Debate Sharpens Focus,” New York Times, October 5, 2004, national edition, A1.
24. Frank Bruni, “Off Sicily, Tide of Bodies Roils the Debate over Immigrants,” New York Times, September 23, 2002, national edition, A1; Al Baker, “Body Falls As Jet Nears Kennedy,” New York Times, August 9, 2001, national edition, A18.
25. Suzanne Daley, “African Migrants Risk All on Passage to Spain,” New York Times, July 10, 2001, national edition, A1 and A6.
26. In a controversial 2004 article in Foreign Policy, the Harvard political scientist Samuel Huntington talked about the eventual result of this flow, with a revealing hint of fear. “In California—as in Hawaii, New Mexico, and the District of Columbia—non-Hispanic whites are now a minority,” he wrote. “Demographers predict that, by 2040, non-Hispanic whites could be a minority of all Americans.” Huntington, ““The Hispanic Challenge,” Foreign Policy (March/April 2004): 41.
27. Bruni, “Off Sicily.”
28. Jagdish Bhagwati, “Borders Beyond Control,” Foreign Affairs 82, no. 1 (January/ February 2003): 98–104.
29. The statistic on U.S. border apprehensions was obtained from the Web site of the U.S. Customs and Border Protection, at http://www.cbp.gov/xp/cgov/home.xml.
30. Rachel Swarns, “Tight Immigration Policy Hits Roadblock of Reality,” New York Times, January 20, 2006, national edition, A12.
31. Ginger Thompson and Sandra Ochoa, “By a Back Door to the U.S.: A Migrant’s Grim Sea Voyage,” New York Times, June 13, 2004, national edition, 1.
32. Charlie LeDuff, “Holidays Inspire a Rush to the Border,” New York Times, December 23, 2004, national edition, A12.
33. Doug Saunders, “European Dream Relies on Immigrant Workers’ Nightmares,” Globe and Mail (Toronto), September 4, 2004, F3.
34. On the dangers in Europe, see Timothy Savage, “Europe and Islam: Crescent Waxing, Cultures Clashing,” Washington Quarterly 27, no. 3 (Summer 2004): 25–50. In the United States, Huntington suggests, the country’s rapid demographic change could eventually cause “the rise of an anti-Hispanic, anti-black, and anti-immigrant movement composed largely of white, working- and middle-class males, protesting their job losses to immigrants and foreign countries, the perversion of their culture, and the displacement of their language.” Huntington, “The Hispanic Challenge,” 41.
35. See, for instance, Ester Boserup, The Conditions of Agricultural Growth: The Economics of Agrarian Change under Population Pressure (Chicago: Aldine, 1965); and Julian Simon, The Ultimate Resource 2 (Princeton: Princeton University Press, 1996). In poor countries, larger populations can provide labor to improve and protect cropland, for instance by building terraces and retaining walls to reduce soil erosion.
36. For a survey of population growth’s manifold social and economic effects, see Dennis Ahlberg, Alan Kelley, and Karen Oppenheim Mason, eds., The Impact of Population Growth on Well-being in Developing Countries (Berlin: Springer-Verlag, 1996).
37. Theodore Panayotou, “An Inquiry into Population, Resources and Environment,” in Ahlberg, Kelley, Mason, eds., The Impact of Population Growth, 259–98. An excellent study of the complex relationship between population growth and local natural resources in poor countries is Scott Templeton and Sara Scherr, “Effects of Demographic and Related Microeconomic Change on Land Quality in Hills and Mountains of Developing Countries,” World Development 27, no. 6 (1999): 903–18.
38. Dennis Ahlburg reviews recent research and thinking about the relationship between population growth and economic performance in “Does Population Matter? A Review Essay,” Population and Development Review 28, no. 2 (June 2002): 329–50.
39. An early statement of this argument is found in Ansley Coale and Edgar Hoover, Population Growth and Economic Development in Low-income Countries: A Case Study of India’s Prospects (Princeton: Princeton University Press, 1959). More recently, some analysts have concluded that lower fertility rates enabled East Asian countries to significantly boost domestic savings, capital investment and, consequently, economic growth from the 1970s into the 1990s. See Matthew Higgins and Jeffrey Williamson, “Age Structure Dynamics in Asia and Dependence on Foreign Capital,” Population and Development Review 23 (1997): 261–93.
40. On rural-urban migration, see Richard Bilsborrow, “Migration, Population Change, and the Rural Environment,” in Environmental Change and Security Program Report 8 (Washington, DC: Woodrow Wilson International Center for Scholars, Environmental Change and Security Program, 2002).
41. United Nations Human Settlements Program, The Challenge of Slums: Global Report on Human Settlements 2003 (London: UN-Habitat and Earthscan Publications, 2003), xxv.
42. The best current survey of world urbanization is United Nations Human Settlements Programme, The State of the World’s Cities 2004/2005: Globalization and Urban Culture (London: Earthscan, 2004), available at http://www.unhabitat.org/mediacentre/sowckit.asp. On urban population growth projections, see Martin Brockerhoff, “Urban Growth in Developing Countries: A Review of Projections and Predictions,” Working Paper: Policy Research Division, no. 131 (New York: Population Council, 1999).
43. United Nations, Department of Economic and Social Affairs, Population Division, Table 1 of World Urbanization Prospects: The 2003 Revision, Data Table and Highlights, available at http://www.un.org/esa/population/publications/wup2003/2003WUPHighlights.pdf, 4; and United Nations Human Settlements Program, The Challenge of Slums, xxv.
44. United Nations, Department of Economic and Social Affairs, Population Division, Table 7 of World Urbanization Prospects, 7.
45. Ibid., Table 8, 8.
46. Martin Brockerhoff and Ellen Brennan, “The Poverty of Cities in Developing Regions,” Population and Development Review 24, no. 1 (1998): 75–114.
47. The resourcefulness and cooperative spirit of slum communities in the face of such obstacles is invariably remarkable. For a detailed account, see Robert Neuwirth, Shadow Cities: A Billion Squatters, a New Urban World (New York: Routledge, 2005).
48. Ellen Brennan, “Population, Urbanization, Environment, and Security: A Summary of the Issues,” Comparative Urban Studies: Occasional Paper Series, no. 22 (Washington, DC: Woodrow Wilson International Center for Scholars, 1999), 12.
49. Seth Mydans, “Eking Out a Living, of Sorts, From a Mountain of Muck,” New York Times, 23 May 2006, national edition.
50. This problem is particularly acute between Central America and the United States. See Ginger Thompson, “Gangs without Borders, Fierce and Resilient, Confound the Law,” New York Times, September 26, 2004, national edition, A1.
51. Larry Rohter, “Ipanema Under Siege: Rio’s Gangs Flex Harder,” New York Times, Sunday Week in Review, October 20, 2002, national edition, 4.
52. As quoted by Rohter, in “Ipanema Under Siege.”
53. On the correlation between youth bulges and political violence, see Henrik Urdal, “A Clash of Generations? Youth Bulges and Political Violence” (Oslo: Centre for Study of Civil War, International Peace Research Institute, Oslo, 2005).
54. Richard Cincotta and Robert Engelman, “Conflict Thrives Where Young Men Are Many,” International Herald Tribune, March 2, 2004. For a more developed treatment of the relationship between youth bulges and civil violence, see Richard Cincotta, Robert Engelman, and Daniele Anastasion, “Appendix 4: Country Data Table,” in The Security Demographic: Population and Civil Conflict after the Cold War (Washington, DC: Population Action International, 2003).
55. Cincotta, Engelman, and Anastasion, “Appendix 4: Country Data Table,” in The Security Demographic, 96–101.
56. The relationship between urban growth and violence is discussed in Thomas Homer-Dixon, Environment, Scarcity, and Violence (Princeton: Princeton University Press, 1999), 155–66.
57. Ibid., 162–63.
58. Between 1976 and 1992, over 140 separate incidents of strikes, riots, and demonstrations took place, mainly in Latin America. See John Walton and David Seddon, Free Markets and Food Riots: The Politics of Global Adjustment (Cambridge: Blackwell Publishers, 1994), 39–40. See also John Walton and Charles Ragin, “Global and National Sources of Political Protest: Third World Responses to the Debt Crisis,” American Sociological Review 55, n. 6 (1990): 876–90; and John Walton, “Debt, Protest and the State in Latin America,” in Power and Popular Protest: Latin American Social Movements, ed. Susan Eckstein (Berkeley: University of California Press, 1989) 299–328.
59. Lewis Mumford discusses cities’ extraction of resources from their hinterlands in “The Natural History of Urbanization,” in William L. Thomas Jr., ed., Man’s Role in Changing the Face of the Earth (Chicago and London: University of Chicago Press, 1956), available at http //habitat.aq.upm.es/boletin/n21/almum.en.html.
60. Greg Aldrete and David J. Mattingly, “Feeding the City: The Organization, Operation, and Scale of the Supply System for Rome,” in D. S. Potter and D. J. Mattingly, eds., Life, Death, and Entertainment in the Roman Empire (Ann Arbor: University of Michigan Press, 1999), 174. See also Geoffrey Rickman, The Corn Supply of Ancient Rome (Oxford: Clarendon Press, 1980), 14–17.
61. Emin Tengström, Bread for the People: Studies of the Corn-Supply of Rome during the Late Empire (Stockholm: Paul Åströms Förlag, 1974), 47–48.
62. Quoted in Aldrete and. Mattingly, “Feeding the City,” 176–77.
1. On the basis of figures provided by the Harvard energy expert John Holdren, assuming a “business-as-usual economic and energy scenario,” global energy use between 2000 and 2050 will rise by a factor of 2.46. See Holdren, “Environmental Change and the Human Condition,” Bulletin of the American Academy of Arts and Sciences 57, no. 1 (Fall 2003): 27.
2. On India’s energy needs, see Somini Sengupta, “Hunger for Energy Transforms How India Operates,” New York Times, June 5, 2005, national edition, 2.
3. Jim Yardley, “China’s Economic Engine Needs Power (Lots of It),” New York Times, Week in Review, March 14, 2004, national edition, 3.
4. China’s desperation is reflected in its leaders’ words. Prime Minister Wen Jiabo declared in early 2004, “We must speed up the development of large coal mines, important power generating facilities and power grids, [and] the exploration and exploitation of petroleum and other important resources.” Quoted in Yardley, “China’s Economic Engine.” See also Keith Bradsher, “China Struggles to Cut Reliance on Mideast Oil,” New York Times, September 3, 2002, national edition, A1; James Kynge, “China Continues Its Quest for Secure Energy Supplies with Variety of Sources As the Aim,” Financial Times, May 25, 2004, 6; Paul Roberts, “The Undeclared Oil War,” Washington Post, June 28, 2004, online edition; Simon Romero, “Canada’s Oil: China in Line As U.S. Rival,” New York Times, December 23, 2004, national edition, A1; and Chris Buckley, “Venezuela Agrees to Export Oil and Gas to China,” New York Times, December 28, 2004, national edition, W1.
5. In the past few years, as the price of oil has shot up, a flurry of articles and books has appeared on the issue of future oil availability. They include James Howard Kunstler, The Long Emergency: Surviving the Converging Catastrophes of the Twenty-First Century (New York: Atlantic Monthly Press, 2005); Kenneth Deffeyes, Beyond Oil: The View from Hubbert’s Peak (New York: Hill and Wang, 2005); David Goodstein, Out of Gas: The End of the Age of Oil (Norton, 2004); Paul Roberts, The End of Oil: On the Edge of a Perilous New World (Boston: Houghton Mifflin, 2004); Kenneth Deffeyes, Hubbert’s Peak: The Impending World Oil Shortage (Princeton: Princeton University Press, 2003); and Richard Heinberg, The Party’s Over: Oil, War and the Fate of Industrial Societies (Gabriola Island, British Columbia: New Society Publishers, 2003).
6. William Nordhaus, “Do Real-Output and Real-Wage Measures Capture Reality? The History of Lighting Suggests Not,” in The Economics of New Goods, Timothy Bresnahan and Robert Gordon, eds. (Chicago: University of Chicago Press, 1997), 29–66.
7. For a fascinating account of the beginnings of the oil age, see Daniel Yergin, The Prize: The Epic Quest for Oil, Money & Power (New York: Free Press, 1992).
8. Specialists use the term “proximate solar energy” for forms of energy derived more or less directly from the sun. The food we eat is proximate solar energy. For an accessible discussion of the transitions described in this paragraph, see Alfred Crosby, Children of the Sun: A History of Humanity’s Unappeasable Appetite for Energy (New York: Norton, 2006).
9. Ian Graham suggested this metaphor of Earth as a fossil-fuel battery charger.
10. The calorific value of crude oil is roughly 12,000 watt hours per kilogram. A fit human male can generate about 500 watt hours of work in an eight-hour day of manual labor. So a kilogram of oil contains heat energy equivalent to about twenty-four days of human manual labor, and about forty grams of oil (roughly equivalent to three tablespoons) contain the equivalent of a day’s labor. Gasoline has about the same calorific value as crude oil. A car’s average forty-litre tank of gasoline weighs about thirty kilograms, and is therefore equivalent to about 720 days of labor.
11. Vaclav Smil, Energy in World History (Boulder, CO: Westview, 1994), 190–91.
12. Transcript of a Global Vision interview with Colin Campbell, available at http://www.global-vision.org/wssd/campbell.html.
13. David Rosenbaum, “As 2 Sides Push, Arctic Oil Plan Seems Doomed,” New York Times, April 18, 2002, national edition, A19
14. Morris Adelman, The Economics of Petroleum Supply (Cambridge, MA: MIT Press, 1993), xi. Emphasis in original text.
15. On U.S. oil imports, see United States Energy Information Administration, “Table 1.7: Overview of U.S. Petroleum Trade,” available at http://www.eia.doe.gov/ emeu/mer/pdf/pages/sec1_15.pdf.
16. OPEC currently has eleven member countries: Algeria, Libya, and Nigeria in Africa; Iran, Iraq, Kuwait, Qatar, Saudi Arabia, and the United Arab Emirates in the Middle East; Venezuela in South America; and Indonesia in Southeast Asia. (Indonesia’s membership may soon end because the country no longer exports oil.) At the time of the 1979–81 oil shock, Gabon and Ecuador were also members.
17. Colin Campbell and Jean Laherrère note that “after the price of crude hit all-time highs in the early 1980s, explorers developed new technology for finding and recovering oil, and they scoured the world for new fields. They found few.” Campbell and Laherrère, “The End of Cheap Oil,” Scientific American 278, no. 3 (March 1998): 81.
18. According to the International Energy Agency, as soon as 2015, Russia, the Persian Gulf, and West Africa will provide 80 percent of the world’s traded oil, and at least a fifth of that oil will have to come from Saudi Arabia alone. See Lord John Browne, “Beyond Kyoto,” a speech to the Council on Foreign Relations, New York, June 24, 2004, available at http://www.cfr.org/pub7148/john_browne/beyond_kyoto.php.
19. R. W. Bentley, “Global Oil & Gas Depletion: An Overview,” Energy Policy 30 (2002): 204. On Shell’s censorship of Hubbert’s address, see Jeremy Leggett, Half Gone: Oil, Gas, Hot Air and the Global Energy Crisis (London: Portobello Books, 2006), excerpted in “What They Don’t Want You to Know about the Coming Oil Crisis,” Independent (London), January 20, 2006.
20. Robert Kaufman points out that this prediction was “part genius and part luck.” The luck came in the form of the Texas Railroad Commission, an organization that controlled the rate of extraction from Texas wells from the 1930s till the 1970s. If the Commission’s decisions had been different, U.S. production could have peaked earlier or later. Still, Kauffmann concludes, the underlying logic of Hubbert’s approach is correct, and its predictions on the timing of peak output are remarkably robust, even when the total oil in a basin turns out to be substantially larger than originally estimated. See Kaufmann, “Planning for the Peak in World Oil Production,” World Watch 19, no. 1 (January/February 2006): 19–21.
21. Between 1970 and 2005, total U.S. production of crude oil and natural gas liquids declined from 11.3 to 6.8 million barrels a day. See “Table 5.1, Petroleum Overview, Selected Years, 1949–2004, available at http://www.eia.doe.gov/emeu/aer/pdf/pages/sec5_5.pdf; and “Table 3.1a, Petroleum Overview: Supply,” available at http://www.eia.doe.gov/emeu/mer/pdf/pages/sec3_2.pdf.
22. When estimating the amount of oil in a region, petroleum geologists and energy specialists distinguish between at least five different quantities: 1. original oil-in-place (the total amount of oil in a basin or region, regardless of its recoverability); 2. cumulative production (the total of all oil extracted so far from a given basin); 3. proved reserves (oil already found in that basin that can be recovered with today’s technologies at a profit); 4. undiscovered reserves (recoverable oil in basins or fields yet to be discovered and explored); and 5. reserve growth (the future increase in the amount of recoverable oil from known basins because of higher prices and new extraction technologies). While estimates of cumulative production for a given basin or region are often fairly solid, those for the other four categories often vary widely. The ultimately recoverable resource, or URR, is the sum of estimates for categories 2 through 5, while the oil recovery factor is this URR divided by the original oil-in-place (i.e., category 1). Estimates of oil recovery currently range from 30 to 70 percent.
23. Estimates of a region’s URR are generally revised as continuing exploration better reveals the full volume of the region’s individual oilfields.
24. Detailed treatments of the mathematical techniques Hubbert used to arrive at his estimates are available in “Hubbert Revisited,” chapter 7 in Deffeyes, Hubbert’s Peak, 133–49; and “The Hubbert Method,” chapter 3 in Deffeyes, Beyond Oil, 35–51.
25. Transcript of a Global Vision interview with Colin Campbell.
26. In the United Kingdom’s North Sea fields, oil discovery peaked in the early 1970s, while production peaked in 1999. Norway reached its discovery peak in 1979 and is passing its production peak right about now. Indonesia’s discovery peaked in 1955 and output peaked in 1977. And in the Persian Gulf, Oman’s oil discovery peaked in 1962, while its output peaked in 2001. Oman’s largest field is now declining at an astonishing 12 percent a year. This country’s experience is a cautionary tale for many in the oil industry because the rapid decline of the Yibal field has occurred despite, and perhaps even because of, aggressive use of new extraction technologies.
Russian discovery peaked in 1960, while its production peaked in 1987. Many analysts, such as Daniel Yergin, head of Cambridge Energy Research Associates (CERA), believe that Russia has huge undiscovered and untapped reserves of oil and will have the capacity to meet a large portion of increased world oil demand in coming decades. Other analysts believe that Russian’s reserves are much more limited and that the country has already passed peak output. For example, R. W. Bentley writes, “There is recognition within the industry that [Russia] is now past its physical resource peak.”
All figures in this note were obtained from the newsletters of the Association for the Study of Peak Oil (available at www.asponews.org) and cross-checked against data from the International Energy Agency’s Oil Market Report (available at http://omrpublic.iea.org/supplysearch.asp). On Oman, see Jeff Gerth and Stephen Labaton, “Oman’s Oil Yield Long in Declining, Shell Data Show,” New York Times, April 8, 2004, online edition. See also Bentley, “Global Oil & Gas Depletion,” 191.
27. Conventional oil consists of light, short-chained molecules and is usually found on land or in shallow waters offshore; non-conventional oil is found in deep water or consists of heavier, longer-chained molecules.
28. Campbell’s estimates as of April 2006, as presented by the Association for the Study of Peak Oil and Gas, can be found in the summary chart on the second page of the Association’s newsletter, available at http://www.peakoil.ie/downloads/newsletters/newsletter64_200604.pdf.
29. USGS World Energy Assessment Team, U.S. Geological Survey World Petroleum Assessment 2000 available at http://greenwood.cr.usgs.gov/energy/WorldEnergy/DDS-60/. See also Thomas Ahlbrandt et al., “Future Oil and Gas Resources of the World,” Geotimes (June 2000): 24–25.
30. John Wood and Gary Long, Long Term World Oil Supply: A Resource Base/Production Path Analysis (Washington, DC: Energy Information Administration, 2000), available at http://www.eia.doe.gov/pub/oil_gas/petroleum/presentations/2000/long_term_supply/index.htm. On the Saudi use of the USGS estimate, see Jeff Gerth, “Doubts Raised on Saudi Vow for More Oil,” New York Times, October 27, 2005, national edition, A1.
31. Some critics contend that the USGS study doesn’t properly account for declining discovery trends in many oil basins and that it uses an unsound method to forecast how much geologists’ estimates of current reserves will grow as they better understand these reserves’ true extent. See Bentley, “Global Oil & Gas Depletion,” 200–201. The USGS study also seems to overstate the likelihood of major new discoveries. So, for example, it includes oil production from a possible basin in East Greenland. On the assumption that there’s a 95 percent chance of finding at least 1 barrel and a 5 percent chance of finding 112 billion barrels, the USGS calculates that the basin will produce 47 billion barrels— a figure that’s then folded into the forecast of the world’s total oil endowment. Yet this Greenland basin hasn’t been explored or even properly tested for its oil content. Colin Campbell comments, “Since the [USGS] numbers were quoted to three decimal places, the reader could be forgiven for assuming them to be accurate. But a moment’s reflection would question the very concept of a subjective 5 percent probability. In plain language, it was a guess that could as well be the half or the double, yet it entered the calculations distorting the critical mean value.” Campbell, “Forecasting Global Oil Supply 2000–2050,” Hubbert Center Newsletter 3 (2002): 2.
32. “USGS Study Revisited,” ASPO Newsletter 63 (March 2006), 10, available at http://www.peakoil.ie/downloads/newsletters/newsletter63_200603.pdf. For an assessment of the USGS’s study’s predictions by the study’s authors themselves, see T. R. Klett, Donald Gautier, and Thomas Ahlbrandt, “An Evaluation of the U.S. Geological Survey World Petroleum Assessment 2000,” American Association of Petroleum Geologists (AAPG) Bulletin 89, no. 8 (August 2005): 1033–42.
33. Some critics note that several of Hubbert’s less well known predictions were seriously off the mark. Others argue that there’s no theoretical reason to assume that oil production will follow a bell curve, so Hubbert’s success in predicting U.S. peak output was just dumb luck. For instance, Michael Lynch writes, “[Hubbert’s] forecast of U.S. gas production in 2000 was 65 percent too low and his world oil production forecast for 2000 was 50 percent too low. Even production in Texas is now about twice the amount he forecast.” To be fair, however, Hubbert admitted that he had far less knowledge of the URR for the world than he did for the lower forty-eight states, and he was therefore reluctant to predict a global peak. See Lynch, “Forecasting Oil Supply: Theory and Practice,” The Quarterly Review of Economics and Finance 42 (2002): 373–89, especially 377. On the lack of a sound theoretical basis for the Hubbert model, see Robert Kauffman and Cutler Cleveland, “Oil Production in the Lower 48 States: Economic, Geological, and Institutional Determinants, The Energy Journal 22, no. 1 (2001): 27–49.
34. For example, see Vaclav Smil, Energy at the Crossroads: Global Perspectives and Uncertainties (Cambridge, MA: MIT Press, 2003), 195–201.
35. Lynch, “Forecasting Oil Supply,” 377–78.
36. Lynch, for example, roundly criticizes all estimates of oil output based on Hubbert’s methodology, declaring that “no major region has yet shown signs of such behavior, outside of the U.S.” Yet in the very next sentence he acknowledges that Egypt, Argentina, and the North Sea “appear to be reaching their peaks,” and one page later he further acknowledges that “Hubbert-style production profiles” have proved “very accurate” for Southeast Asia. Furthermore, the data series that he presents to refute Campbell’s projection for the United Kingdom omits the sharp downturn in UK production since 1999. See Lynch, “Forecasting Oil Supply,” 376–77, 381. Kauffman and Cleveland assert that three “stochastic trends” that critically affected lower forty-eight output “are not present in the deterministic [Hubbert] Bell-shaped curve.” But their incorporation of these trends in their model simply allows them to reproduce the variance in lower forty-eight production around an overall Hubbert bell-shaped trend line. Moreover, one of the key pieces of evidence these authors use to refute a Hubbert-style model of U.S. oil output is that “production in the lower 48 States stabilizes in the late 1970s and early 1980s, which contradicts the steady decline forecast by the Hubbert model.” But the Hubbert model doesn’t preclude considerable variation around a long-term secular trend of declining output; also, the particular episode of stabilized production that the authors highlight lasted only five years, whereas the trend of declining production in the United States has been otherwise uninterrupted for thirty-five years. See Kauffman and Cleveland, “Oil Production,” 46–47, especially Figure 3.
37. In the past, tough U.S. federal regulations encouraged major oil-producing companies to underreport their oil reserves. Underreporting didn’t cause problems when newly discovered oil fields tended to be large and their oil easy to extract. Once the oil started flowing, the producers could then revise upward their fields’ reserves, which kept shareholders, bankers, and other investors happy. Unfortunately, though, these steady upward revisions encouraged investors and commentators to become excessively optimistic about oil’s long-term availability and about the ability of new technologies to boost the fraction of oil that could be recovered from existing fields.
As large oil fields became depleted and supplies tightened, the scope for underreporting narrowed. Major oil companies thus had less slack in their reserve estimates to counterbalance, in the eyes of investors, any of the bad news from failed exploration that’s inevitably part of the oil business. And as new discoveries became smaller, with harder-to-extract oil, companies came under pressure to exaggerate the size of these discoveries to attract investor interest at all. As a result, some companies appear to have moved from systematic underreporting of their reserves, at least within the U.S., to the exact opposite practice—systematic overreporting— especially of overseas reserves. In early 2004, for instance, Royal Dutch/Shell, the world’s third-largest oil company, had to revise its figures for its oil and gas reserves downward by a stunning 22 percent. Overall, too, the long-standing link between large corporate reserves and high production has weakened: while the stated reserves of major oil-producing companies have risen in recent years, these companies’ oil output has generally declined, which suggests reserve figures have been inflated. On this last point, see Alex Berenson, “An Oil Enigma: Production Falls Even as Reserves Rise,” New York Times, June 12, 2004, online edition.
38. Quoted in ibid.
39. See, for example, John F. Bookout, “Two Centuries of Fossil Fuel Energy,” Episodes 12 4 (1989): 257–62.
40. Harry Longwell backdated upward revisions (to a given oil field’s total size) to the year that the field was discovered. This procedure requires some explanation. When a field is discovered, geologists estimate its size in terms of its total content of oil (usually assuming a certain oil price, which determines how hard producers would be willing to work to extract the oil). Over time, as field-imaging technology improves, and as production wells are drilled into the field, geologists update the estimated total amount in the field, which in the past has usually meant an upward revision (sometimes substantial). Longwell has attributed these revisions to the year that the original field was discovered rather than to the year that a given revision was made. This allows the graph of global oil discovery shown here to represent the fact that most—if not all—of the really big fields have already been discovered. In recent years, geologists’ techniques for predicting the ultimate size of a field have greatly improved, which means that their estimates of the size of any newly discovered fields are less likely to be revised upward substantially in the future (to the extent that revisions occur, they are just as often downward now). So we can be reasonably confident that the declining tail of the world discovery trend in the graph represents a genuine long-term diminishment of oil discovery.
41. This point is well established in the energy literature. See, for instance, John Hallock Jr. et al., “Forecasting the Limits to the Availability and Diversity of Global Conventional Oil Supply,” Energy 29, no. 11 (September 2004): 1673–96, especially 1681; and Robert Hirsch, Roger Bezdek, and Robert Wendling, Peaking of World Oil Production: Impacts, Mitigation, & Risk Management (San Diego: Science Applications International Corporation, 2005), 17.
42. Harry Longwell, “The Future of the Oil and Gas Industry: Past Approaches, New Challenges,” World Energy 5, n. 3 (2002): 100–104.
43. Charles Hall et al., “Hydrocarbons and the Evolution of Human Culture,” Nature 426, no. 6964 (November 20, 2003): 320; and Cutler Cleveland, “Net Energy from the Extraction of Oil and Gas in the United States,” Working Paper 0101, Center for Energy and Environmental Studies and Department of Geography, Boston University. Available at http://www.bu.edu/cees/research/workingp/pdfs/NetEnergy_w=figures.doc.pdf. The final version of this paper was published as Cutler Cleveland, “Net Energy from the Extraction of Oil and Gas in the United States,” Energy 30, no. 5 (April 2005): 769–82. On the worldwide trend toward higher costs of exploration, see Jad Mouawad, “Oil Explores Searching Ever More Remote Areas,” New York Times, September 9, 2004, national edition, C1.
44. Data on the average cost (in inflation-adjusted dollars) of producing oil in the U.S. are available from Kauffman and Cleveland, “Oil Production,” Figure 2, 43.
45. Matthew Simmons, The World’s Giant Oilfields (Houston: Simmons & Company International, 2001).
46. Campbell and Laherrère, “The End of Cheap Oil,” 82.
47. In 2005, ExxonMobil issued a report, The Outlook for Energy: A 2030 View, indicating that non-OPEC conventional oil production will peak in 2010. Afterward, the report indicates, rising demand will have to be met by non-conventional oil sources, especially oil sands and natural gas liquids, and OPEC conventional production, mainly from the Persian Gulf. On the important role of the Middle East in meeting future demand, see also International Energy Agency, World Energy Outlook 2005: Middle East and North Africa (Paris: IEA, 2005). The report states, “The oil and gas resources of the Middle East and North Africa (MENA) will be critical to meeting the world’s growing appetite for energy. The greater part of the world’s remaining reserves lie in that region. They are relatively under-exploited and are sufficient to meet rising global demand for the next quarter century and beyond.”
48. For example, the U.S. Department of Energy (DOE) estimated in 2005 that Saudi Arabia will be able to boost its output from the current 9.5 million to 14 million barrels a day as soon as 2010 and to more than 15 million barrels a day by 2020. This 2005 DOE estimate of Saudi 2020 production is substantially lower than a 2002 DOE estimate of 20 million barrels a day that was widely thought unrealistic by specialists. The 2005 estimates are available at http://www.eia.doe.gov/oiaf/ieo/pdf/ieooiltab_1.pdf. On the 2002 estimates, see Jeff Gerth, “Growing U.S. Need for Oil from the Mideast Is Forecast,” New York Times, December 26, 2002, national edition, A16. More recently, the International Energy Agency in its World Energy Outlook 2005 has estimated Saudi output at over 18 million barrels a day in 2030.
49. The energy investment banker Matthew Simmons writes, “The accounts of Saudi exploration activities as related in technical papers from Aramco [the Saudi national oil company] confirm that there has … been intensive exploration in Saudi Arabia for the past thirty years, and that the effort has brought only marginal success.” Simmons, Twilight in the Desert: The Coming Saudi Oil Shock and the World Economy (Hoboken, NJ: Wiley, 2005), 241.
50. The Association for the Study of Peak Oil, “Saudi Arabia,” ASPO Newsletter 21 (September 2002), 3–6, available at http://www.peakoil.ie/downloads/newsletters/newsletter21_200209.pdf.
51. The best publicly accessible account of the state of the Ghawar field is provided by Simmons in “Ghawar, the King of Oilfields,” chapter 7 in Twilight in the Desert, 151–79. Simmons provides production estimates on 152–54.
52. Ibid., 161–65.
53. The Association for the Study of Peak Oil, “Saudi Arabia.”
54. The country’s actual reserves are unlikely to be more than 200 and could even be less than 90 billion barrels. See ibid; and also the Association for the Study of Peak Oil and Gas, “Saudi Reserves,” ASPO Newsletter 40 (April 2004): 3, available at http://www.peakoil.ie/downloads/newsletters/newsletter40_200404.pdf.
55. Jeff Gerth, “Forecast of Rising Oil Demand Challenges Tired Saudi Fields,” New York Times, February 24, 2004, national edition, A1.
56. In 2004, the U.S. administration received a key intelligence report questioning Saudi Arabia’s long-term capacity to meet global demand for conventional oil. See Gerth, “Doubts Raised on Saudi Vow for More Oil.” See also Peter Mass, “The Breaking Point,” New York Times Magazine (August 21, 2005): 30.
57. Jim Giles, “Every Last Drop,” Nature 429, no. 6993 (June 17, 2004): 694–95.
58. According to Matthew Simmons, who has been a financial adviser to oil-field service companies for three decades, oil-field managers have learned that “these advances combined to extract the easily recoverable oil from giant fields even faster and led to decline curves, once reservoir pressures depleted, steeper than the industry had ever experienced before.” Elsewhere he writes, “The industry is beginning to appreciate that advanced technologies … are essentially turbo-charged super-straws designed to suck out the recoverable oil faster—not miracle drugs that prolong field life and recover far higher percentages of the original oil-in-place.” Simmons, Twilight in the Desert, 337, 279. See also Bentley, “Global Oil & Gas Depletion,” 195.
59. Oil production (encompassing conventional and unconventional oil, including natural gas liquids) currently averages about 80 million barrels a day. The U.S. Energy Information Agency estimates that this production will need to grow to 120 million barrels a day by 2025 to meet the growing demand especially of China and India. See Energy Information Administration, “International Energy Outlook 2005,” available at http://www.eia.doe.gov/oiaf/ieo/oil.html.
60. See, for instance, Cambridge Energy Research Associates (CERA), “Oil & Liquids Capacity to Outstrip Demand Until at Least 2010: New CERA Report,” press release, June 21, 2005, available at http://www.cera.com/news/ details/1,2318,7453,00.html.
61. Simon Romero, “Mr. Sandman, Bring Me Some Oil,” New York Times, August 31, 2004, national edition, C1.
62. The calorific value of thirty cubic meters of natural gas is about one-fifth of that of a barrel of crude oil. Any complete EROI estimate would also have to include the energy involved in mining and transporting the raw tar sands, as well as energy to pump water and deal with wastes.
63. Technologies are now being developed for “in situ” production of tar sands oil using energy in the tar sands themselves, but they are still experimental.
64. With somewhat tongue-in-cheek immodesty, the Princeton University petroleum engineer Kenneth Deffeyes has used a Hubbert-type analysis to specify November 24, 2005 (American Thanksgiving Day), as the likely date of peak output. Because it takes a while for a trend to appear in oil production data, we won’t know a couple of years whether this prediction is correct. Deffeyes, Beyond Oil, 3.
65. See CERA, “Oil & Liquids Capacity.”
66. “Relatively large uncertainties about recoverable oil supply have relatively little effect on the timing of the peak…. Optimistic estimates for the amount of oil that remains only postpone the peak slightly.” See Robert Kaufmann, “Planning for the Peak in World Oil Production,” World Watch 19, no. 1 (January/February 2006): 19. The energy analyst John Hallock Jr. and his colleagues have predicted the time frame within which peak output is likely to occur. They write, “Global production of conventional oil will almost certainly begin an irreversible decline somewhere between 2004 and 2037.” Hallock Jr. et al., “Forecasting,” 1673.
67. Bentley, “Global Oil & Gas Depletion,” 202. The post-peak depletion rate could be much higher: executives of oil-field service companies have noted that the average post-peak depletion rate for older reservoirs is around 8 percent.
68. Daniel Yergin and his researchers at Cambridge Energy Research Associates (CERA) have proposed that global oil output will not peak but reach an “undulating plateau” in the third or fourth decade of this century, and that this plateau will continue for several decades. See CERA, “Oil & Liquids Capacity.”
69. As quoted in Dow Jones Newswires and reproduced at the Culture Change website: http://www.culturechange.org/fall_of_petroleum_DowJones.html.
70. Some of the material in the following paragraphs was written in collaboration with S. Julio Friedmann of Lawrence Livermore Laboratory. For a survey of advantages and disadvantages of the energy sources discussed here, see chapters 4 through 9 of Deffeyes, Beyond Oil.
71. For data on the number of natural gas wells drilled in the U.S. and on natural gas production and price, see U.S. Energy Information Administration, “Table 5.2: Crude Oil and Natural Gas Wells Drilled,” available at http://www.eia.doe.gov/ emeu/mer/pdf/pages/sec5_4.pdf; “Table 4.2: Natural Gas Production,” available at http://www.eia.doe.gov/emeu/mer/pdf/pages/sec4_4.pdf; and “Table 9.11: Natural Gas Prices,” available at http://www.eia.doe.gov/emeu/mer/pdf/pages/ sec9_17.pdf.
72. Although the natural gas industry has downplayed the danger of LNG explosions, Jerry Havens, a professor of chemical engineering at the University of Arkansas and an adviser to the U.S. Coast Guard, argues that there is a genuine danger of “pool fires” caused by LNG that accumulates on the surface of the ground or the sea after catastrophic release from a tanker: “Most predictions suggest that even the largest LNG tankers (typically more than 900 feet in length) might be completely enveloped in a pool fire following a complete spill of a single 6.5 million gallon tank…. A typical LNG tanker contains as many as five tanks with a combined capacity of 33 million gallons. [Such fires] would be expected to burn more rapidly and with greater intensity than crude oil or even gasoline fires.” See Jerry Havens, “Terrorism: Ready to Blow?” Bulletin of the Atomic Scientists 59, no. 4 (July/August 2003): 16–18.
73. This technology is described in S. Julio Friedmann and Thomas Homer-Dixon, “Out of the Energy Box,” Foreign Affairs 83, no. 6 (November/December 2004): 72–83.
74. Tad Patzek, “Thermodynamics of the Corn-Ethanol Biofuel Cycle,” Critical Reviews in Plant Sciences 23, no. 6 (2004): 519–67, available at http://petroleum.berkeley.edu/papers/patzek/CRPS416-Patzek-Web.pdf.
75. Arthur Ragauskas, “The Path Forward for Biofuels and Biomaterials,” Science 311, no. 5760 (January 27, 2006): 484–89.
76. An excellent discussion of the power-density issue is available in Smil, Energy at the Crossroads, 240–44.
77. Declan Butler, “Nuclear Power’s New Dawn,” Nature 429, no. 6989 (May 20, 2004): 238–40.
78. Paul Grant, “Hydrogen Lifts Off—With a Heavy Load,” Nature 424, no. 424 (July 10, 2003): 129–30.
79. Holdren, “Environmental Change and the Human Condition,” 30. Ernst von Weizsäcker, Amory Lovins, and Hunter Lovins argue that resource and energy productivity can increase 4 to 5 percent a year. See Weizsäcker, Lovins, and Lovins, Factor Four: Doubling Wealth, Halving Resource Use, The New Report to the Club of Rome (London: Earthscan, 1997), 142.
80. American Iron and Steel Institute, “U.S. Steel Industry: World Leaders in Energy Efficiency,” available at http://www.steel.org/AM/Template.cfm?Section=Home&TEMPLATE=/CM/ContentDisplay.cfm&CONTENTID=13399.
81. Statistics available from the U.S. Energy Information Administration, “Table 1.5: Energy Consumption, Expenditures, and Emissions Indicators, 1949–2004,” available at http://www.eia.doe.gov/emeu/aer/txt/ptb0105.html.
82. Campbell, “Forecasting.”
1. M. J. R. Wortel and W. Spakman, “Subduction and Slab Detachment in the Mediterranean-Carpathian Region,” Science 290, no. 5498 (December 8, 2000): 1910–17.
2. Renato Funiciello et al., “Seismic Damage and Geological Heterogeneity in Rome’s Colosseum Area: Are They Related?” Annali di Geofisica 38, no. 5–6 (November-December 1995): 927–37.
3. V. I. Keilis-Borok, “The Concept of Chaos in the Problem of Earthquake Prediction,” in The Impact of Chaos on Science and Society, ed. Celso Grebogi and James Yorke (Tokyo: United Nations University Press, 1997), 243–54, especially 245.
4. Ross Stein, “Earthquake Conversations,” Scientific American 288, no. 1 (January 2003): 72–79. On the consequences of the great December 2004 Indonesian earthquake, see Kenneth Chang, “Post-Tsunami Earthquakes Rumbled around the Globe,” New York Times, May 24, 2005, national edition, D3.
5. Matthew Gerstenberger et al., “Real-Time Forecasts of Tomorrow’s Earthquakes in California,” Nature 435 (May 19, 2005): 328–31. The current debate about the prospects for earthquake prediction is summarized in David Cyranoski, “A Seismic Shift in Thinking,” Nature 431, no. 7012 (October 28, 2004): 1032–34. Some of today’s most advanced methods of prediction rely on analysis of earthquake precursors—patterns of seismicity—to identify regions with a high likelihood of large earthquakes. See, in particular, Vladimir Keilis-Borok, “Reverse Tracing of Short-term Earthquake Precursors,” Physics of the Earth and Planetary Interiors 145, no. 1–4 (July 30, 2004): 75–85, and Vladimir Keilis-Borok, “Intermediate-term Earthquake Prediction,” Proceedings of the National Academy of Sciences, USA 93 (April 1996): 3748–55.
6. Susan Hough, Earthshaking Science: What We Know (and Don’t Know) about Earthquakes (Princeton: Princeton University Press, 2002), 111.
7. In seismically active zones, small tremors occur all the time, yet an earthquake follows only about 5 percent of them.
8. “Some experts have speculated that once all the damages from the California Wildfires of 2003 are tabulated (provisionally estimated at about $1.7—S3.5 billion), [the total] may rival the costliest fire incident in California’s history, which occurred following the 1906 San Francisco Earthquake, which caused $5.7 billion in damages, in inflation-adjusted dollars.” Federal Emergency Management Agency, The California Fires Coordination Group: A Report to the Secretary of Homeland Security (Washington, DC: U.S. Department of Homeland Security, 2004), 9; available at http://permanent.access.gpo.gov/websites/www.fema.gov/pdf/library/draft_cfcg_report_0204.pdf.
9. Although social science research often fails to recognize the danger of negative synergy, an exception is research on the causes of urban decay in the United States. See, for instance, R. Wallace and D. Wallace, “Resilience and Persistence of the Synergism of Plagues: Stochastic Resonance and the Ecology of Disease, Disorder, and Disinvestment in US Urban Neighborhoods,” Environment and Planning A 29 (1997): 789–804. The risk posed by negative synergy among environmental stresses is also discussed in Will Steffen et al., “Abrupt Changes: The Achilles’ Heels of the Earth System,” Environment 46, no. 3 (April 2004): 8–20. The authors write, “How many [environmental] stresses, occurring when and where would it take for the global economic system to begin a downward, self-reinforcing spiral that would lead to a rapid collapse?”
10. Federal Emergency Management Agency, The California Fires Coordination Group, 11.
11. Says Craig Allen, a research ecologist with the United States Geological Survey in New Mexico, “As the climate is changing, these ecosystems are rearranging themselves. Massive forested die-back is one way these systems will reassemble.” Quoted in Jim Robbins, “Beetles Take a Devastating Toll on Western Forests,” New York Times, July 13, 2004, national edition, D4.
12. As Mike Davis, professor of history at the University of California in Irvine and author of well-known books about urbanization in Southern California, says, “These dead forests represent an almost apocalyptic hazard to more than 100,000 mountain and foothill residents, many of whom depend on a single, narrow road for their fire escape.” Davis, “The Perfect Fire,” History News Network, Center for History and New Media, George Mason University, October 27, 2003, available at http://hnn.us/articles/1761.html.
13. This definition of breakdown actually subsumes the word’s conventional meaning: a system’s simplification will likely disrupt its regular functions, while a breakdown of a system’s regular functions will, at least over time, lead to its simplification. My definitions of breakdown and collapse in these paragraphs are adapted from Joseph Tainter’s “Comments on the Symposium ‘I Fall to Pieces: Global Perspectives on the Collapse of Complex Systems,’” presented at the 65th Annual Meeting of the Society for American Archaeology, Philadelphia, April 8, 2000. See also Tainter, Collapse, 4, 31. Jared Diamond offers a similar definition in Collapse: How Societies Choose to Fail or Succeed (New York: Viking, 2005), 3.
14. Note that simpler doesn’t mean easier. In fact, in most cases everyday tasks became much harder. We usually introduce complexity into our lives in order to make things easier for us, so when this complexity fails, life often becomes harder.
15. For overviews of common explanations of societal collapse, see “The Study of Collapse,” chapter 3 in Joseph Tainter, The Collapse of Complex Societies (Cambridge: Cambridge University Press, 1988), 39–90; Tainter, “Theories of the Collapse of States,” The Oxford Companion to Archeology, ed. Brian Fagan et al. (Oxford: Oxford University Press, 1996), 688–90; and Norman Yoffee, “Orienting Collapse,” chapter 1 in Norman Yoffee and George Cowgill, eds., The Collapse of Ancient States and Civilizations (Tucson: University of Arizona Press, 1988), 1–19. Bert Useem reviews recent sociological theories of civil violence such as riots and rebellions in “Breakdown Theories of Collective Action,” Annual Review of Sociology 24 (1998): 215–38.
16. Overload-breakdown theories of this form have an honorable pedigree derived from at least three distinct lines of research and thought: the functionalist sociology of Emile Durkheim and Talcott Parsons; the systems theory and cybernetics pioneered by Ludwig von Bertalanffy and Norbert Wiener; and the information-processing and computational theories of cognitive scientists and organizational theorists like Herbert Simon. Durkheim’s most relevant work is his study of suicide; ideas of overload and breakdown are implicit in his theories of both “egoistic” and “anomic” suicide. Parsons, in his discussion of social change, argues that “strain” can upset the “balance between forces tending toward reequilibration of the previous structure and toward transition to a new structure.” In political science, Karl Deutsch, Samuel Huntington, and Alexander Motyl, among others, have proposed overload-breakdown theories of social and political change. Huntington, for instance, argues that societies are vulnerable to instability when their level of political participation exceeds their level of political institutionalization. See Émile Durkeim, Suicide: A Study in Sociology, trans. John A. Spaulding and George Simpson (Glencoe, IL: Free Press, [1897] 1951); Talcott Parsons, chapter 11, “The Processes of Change of Social Systems,” in The Social System (Glencoe, IL: Free Press, 1951), especially 493; Ludwig von Bertalanffy, “An Outline of General System Theory,” British Journal for the Philosophy of Science 1, no. 2 (August 1950): 134–65; Norbert Wiener, Cybernetics: Or Control and Communication in the Animal and the Machine (Cambridge, MA: MIT Press, 1961); Herbert Simon, Reason in Human Affairs (Stanford: Stanford University Press, 1983), especially chapter 3, “Rational Processes in Social Affairs,” 75–107; Karl Deutsch, “Cracks in the Monolith: Possibilities and Patterns of Disintegration in Totalitarian Systems,” in Carl J. Friedrich, ed., Totalitarianism: Proceedings of a Conference Held at the American Academy of Arts and Sciences (Cambridge, MA: Harvard University Press, 1954), 308–33; Samuel Huntington, Political Order in Changing Societies (New Haven: Yale University Press, 1968), especially 79 and 274–78; and Alexander Motyl, Imperial Ends: The Decay, Collapse, and Revival of Empires (New York: Columbia University Press, 2001), 50–53.
17. For a discussion of the sources of this extraordinary adaptability, see Thomas Homer-Dixon, The Ingenuity Gap: Facing the Economic, Environmental, and Other Challenges of an Increasingly Complex and Unpredictable Future (New York: Vintage, 2002), 306–307.
18. The political scientist Robert Jackson calls these countries “quasi-states.” See Jackson, “Quasi-states, Dual Regimes, and Neoclassical Theory: International Jurisprudence and the Third World,” International Organization 41, no. 4 (Autumn 1987): 519–49.
19. “Speed,” as I use the term here, is a composite variable incorporating both the velocity of movement of material, energy, or information along a link between two nodes and the average density of each “package” of material, energy, or information that moves along the link. It is, therefore, essentially the link’s transmission capacity.
20. Also, the nodes themselves tend to become more complex, as the people who create and operate them try to make them perform better. For example, a manufacturing company might improve the efficiency of its production processes by adopting more sophisticated methods for inventory control. W. Brian Arthur shows that competition among entities in a co-evolutionary environment (for instance, among corporations in a market or among organisms in an ecosystem) boosts the complexity of the entities as they try to survive by improving their performance, a process he calls “structural deepening.” See Arthur, “On the Evolution of Complexity,” in Complexity: Metaphors, Models, and Reality, ed. G. Cowan, D. Pines, and D. Meltzer, Santa Fe Institute Studies in the Sciences of Complexity, Proceedings, Vol. 19 (Reading, MA, 1994), 65–78.
21. About a century ago, the great French sociologist Émile Durkheim, who dominated French social thought during the late nineteenth and early twentieth centuries, referred to the general phenomenon of growing connectivity and speed as the rising “dynamic density” of human societies. He argued that greater dynamic density resulted from the growth in human population, its increasing concentration in cities, and the rapid development of communication and transportation technologies; dynamic density in turn stimulated the economic division of labor. See Durkheim, The Division of Labor in Society, trans. George Simpson (New York: Free Press, 1968 [1933]), 257.
22. The classic discussion of tight coupling is Charles Perrow, Normal Accidents: Living with High-Risk Technologies (New York: Basic, 1984).
23. For a discussion of key factors, including human demographics and travel, promoting the emergence of infectious disease, see chapter 3, “Factors in Emergence,” in Mark Smolinski, Margaret Hamburg, and Joshua Lederberg, eds., Microbial Threats to Health: Emergence, Detection, and Response (Washington, DC: Institute of Medicine of the National Academies, National Academy Press, 2003), 53–148.
24. For an explanation of stock market booms and crashes that highlights self-reinforcing feedback loops in complex systems, see Didier Sornette, Why Stock Markets Crash: Critical Events in Complex Financial Systems (Princeton: Princeton University Press, 2003).
25. On failures arising from new links between previously isolated systems, see Dietrich Dörner, The Logic of Failure: Recognizing and Avoiding Error in Complex Situations, trans. Rita and Robert Kimber (Cambridge, MA: Perseus, 1996). On failures arising from new links inside systems (that is, new links between previously separated system components), which the Yale sociologist Charles Perrow famously calls “normal accidents,” see Perrow, Normal Accidents, especially chapter 3, “Complexity, Coupling, and Catastrophe,” 62–100. Scott Sagan reviews the influence of Perrow’s book in Sagan, “Learning from Normal Accidents,” Organization & Environment 17, no. 1 (March 2004): 15–19.
26. Researchers have found that human, organizational, and sociocultural factors are often deep causes of this kind of breakdown. Organizations, including NASA before the Columbia disaster, can have structures or cultures that get in the way of communication between groups responsible for designing, maintaining, and running a system or that encourage people to neglect proper testing, training, and safety procedures. See William Evan and Mark Manion, Minding the Machines: Preventing Technological Disasters (Upper Saddle River, NJ: Prentice Hall PTR, 2002); and James Reason, Human Error (Cambridge: Cambridge University Press, 1990), 173. The evolution of thinking about organizational errors is summarized in Karlene H. Roberts, “Organizational Errors: Catastrophic,” in Neil J. Smelser et al., eds., International Encyclopedia of the Social and Behavioral Sciences, Vol. 16 (Amsterdam: Elsevier, 2001), 10942–45. For a remarkable account of these organizational causes in the case of the Columbia disaster, see the Columbia Accident Investigation Board, Report Volume I (Government Printing Office, Washington, DC: NASA, August 2003).
27. Eric Lerner, “What’s Wrong with the Electric Grid?” The Industrial Physicist (American Institute of Physics, October-November 2003): 8–13; and James Glanz and Andrew Revkin, “Set of Rules Too Complex to Be Followed Properly, or Not Complex Enough,” New York Times, August 19, 2003, national edition, A20.
28. Andrew Revkin, “Experts Point to Strains on Electric Grid’s Specialists,” New York Times, September 2, 2003, national edition, A12. For a complete assessment of the causes of the 2003 blackout, see U.S.-Canada Power System Outage Task Force, Final Report on the August 14, 2003, Blackout in the United States and Canada: Causes and Recommendations (Washington, DC, and Ottawa: U.S. Department of Energy and Ministry of Natural Resources Canada, April 2004).
29. Accessible summaries of this research are Albert-László Barabási, Linked: The New Science of Networks (Cambridge, MA: Perseus, 2002); and Duncan Watts, Six Degrees: The Science of a Connected Age (New York: Norton, 2003). See also Albert-László Barabási and Eric Bonabeau, “Scale-Free Networks,” Scientific American 288, no. 5 (May 2003): 60–69.
30. The airline financial crisis following the 9/11 attacks encouraged many U.S. airlines to move away from a hub-and-spoke routing arrangement.
31. In the language of statistics, the frequency distribution of nodes in a random network (when graphed according to the number of links per node) forms a bell-shaped curve. The distribution of a scale-free network, in contrast, forms a declining curve that drops quickly at first and then has a long, slowly diminishing tail, as illustrated ahead. (In technical terms, this is a “power-law” distribution.) The network’s hubs are at the end of the tail. Such networks are called scale-free because, in contrast to random networks, there’s no typical or “average” number of links between nodes.
Frequency distributions of random and scale-free networks
32. There is some dispute among specialists about whether the North American electricity grid is scale-free. L. A. N. Amaral et al. argue that it is not in “Classes of Small-World Networks,” in Proceedings of the National Academy of Sciences of the United States of America 97, no. 21 (October 10, 2000): 11149–52, while Albert-László Barabási and Réka Albert present evidence indicating that it is in “Emergence of Scaling in Random Networks,” Science 286 (October 15, 1999): 509–12. A close look at the respective authors’ interpretation of the data supports, I believe, the assessment of Barabási and Albert, although all these authors undertake only a static analysis of network architecture that neglects the variable carrying capacities of different links.
33. Ricard Solé and José Montoya, “Complexity and Fragility in Ecological Networks,” Proceedings of the Royal Society of London 268 (2001): 2039–45.
34. On the role of urbanization in the emergence and spread of infectious disease, see Smolinski, Hamburg, and Lederberg, eds., Microbial Threats to Health, 81–85.
35. Some of the material in the following paragraphs appeared in Thomas Homer-Dixon, “The Rise of Complex Terrorism,” Foreign Policy, no. 128 (January/February 2002): 52–62. For similar arguments, see the comments by John Robb, a security analyst with a background in counterterrorism and complex systems analysis, on his blog at http://globalguerrillas.typepad.com/globalguerrillas/.
36. In 1997, a special investigative commission set up by President Bill Clinton reported that “growing complexity and interdependence, especially in the energy and communications infrastructures, create an increased possibility that a rather minor and routine disturbance can cascade into a regional outage.” Technical complexity, the Commission continued, echoing Charles Perrow’s concept of normal accidents, “may also permit interdependencies and vulnerabilities to go unrecognized until a major failure occurs.” The Commission concluded, “We are convinced that our vulnerabilities are increasing steadily, that the means to exploit those weaknesses are readily available and that the costs associated with an effective attack continue to drop.” Report of the President’s Commission on Critical Infrastructure Protection, Critical Foundations: Protecting America’s Infrastructures (Washington, DC: 1997): x. See also Massoud Amin, “National Infrastructures as Complex Interactive Networks,” in Tariq Samad and John Weyrauch, eds, Automation, Control, and Complexity: New Developments and Directions (John Widely and Sons, 1999).
37. I describe a scenario for a terrorist attack against the U.S. electricity grid in the opening paragraphs of Homer-Dixon, “The Rise of Complex Terrorism.”
38. Adilson Motter and Ying-Cheng Lai, “Cascade-Based Attacks on Complex Networks,” Physical Review E 66, 065102 (Rapid Communication) (2002). See also Steven Rinaldi, James Peerenboom, and Terrence Kelly, “Identifying, Understanding, and Analyzing Critical Infrastructure Interdependencies,” IEEE Control Systems Magazine (December, 2001): 11–25.
39. Langdon Winner, “Complexity and the Limits of Human Understanding,” in Organized Social Complexity: Challenge to Politics and Policy, ed. Todd La Porte (Princeton: Princeton University Press, 1975): 69–70.
40. McKinsey & Company, Banking & Securities Practice, “Impact of Attack on New York Financial Services” (November, 2001), available at http://www.mckinsey.com/ideas/articles/ImpactofAttack.asp.
41. In its December 2001 statement on prospects for the world economy, the International Monetary Fund estimated the global GDP would be 1 percent lower in 2002 than it would have been in the absence of the attacks. This works out to a loss, in one year, of around $300–400 billion. Such lost productivity produces a stream of future losses (because of forgone investment, among other things). In 2002, the discounted present value of that year’s loss plus future losses would have easily exceeded $1 trillion. See International Monetary Fund, World Economic Outlook: The Global Economy after September 11 (Washington, DC: IMF, December 2001), 4, available at http://www.imf.org/external/pubs/ft/weo/2001/03/index.htm.
42. Jack Goldstone, Revolution and Rebellion in the Early Modern World (Berkeley: University of California Press, 1991), 469. (Emphasis in original.) Goldstone explicitly adopts an earthquake analogy for revolution. See also Jack Goldstone and Bert Useem, “Prison Riots as Microrevolutions: An Extension of State-Centered Theories of Revolution,” American Journal of Sociology 104, no. 4 (January 1999): 985–1029; and Jack Goldstone, “Toward a Fourth Generation of Revolutionary Theory,” in Nelson Polsby, ed., Annual Review of Political Science, Vol. 4, 2001 (Palo Alto, CA: Annual Reviews, 2001), 139–87.
43. Goldstone, Revolution and Rebellion, 36.
44. Marten Scheffer et al., “Catastrophic Shifts in Ecosystems,” Nature 413 (October 11, 2001): 591–96.
45. The practice of “sustainable yield” resource management, as often applied to fisheries and other renewable-resource systems, frequently sets an allowable rate of extraction above the level the system can sustain given its natural fluctuations in productivity. See Donald Ludwig, Ray Hilborn, and Carl Walters, “Uncertainty, Resource Exploitation, and Conservation: Lessons from History,” Science 260, no. 5104 (April 2, 1993): 17, 36. On sensitivity of cod stocks to fluctuations in temperature and salinity, see Alida Bundy and L. Paul Fanning, “Can Atlantic Cod (Gadus morhua) Recover? Exploring Trophic Explanations for the Non-Recovery of the Cod Stock on the Eastern Scotian Shelf, Canada” Canadian Journal of Fisheries and Aquatic Sciences 62, no. 7 (July, 2005): 1474–90; and E. Meltzer, Overview of the East Coast Marine Environment (Ottawa: Canadian Arctic Resources Committee/Canadian Nature Federation, 1995).
46. For further details, see David Webster, The Fall of the Ancient Maya: Solving the Mystery of the Maya Collapse (London: Thames and Hudson, 2002); and Richardson Gill, The Great Maya Droughts: Water, Life, and Death (Mexico City: University of New Mexico Press, 2000). Webster emphasizes the role of population growth and Gill the role of drought in the Mayan collapse. Gill also uses an energy-based, complex-systems model similar to that adopted in this book. Jared Diamond summarizes the findings of these and many other works and their implications for modern industrial society in “The Last Americans: Environmental Collapse and the End of Civilization,” Harper’s Magazine (June 2003): 43–51. See also chapter 5, “The Maya Collapses,” in Diamond, Collapse, 157–77. For an overview of the relationship between climate change and societal collapse, see Harvey Weiss and Raymond Bradley, “What Drives Societal Collapse?” Science 291, no. 5504 (January 26, 2001): 609–10.
47. The great Belgian historian Henri Pirenne argued in the 1930s that the Germanic invasions of the West in the fifth century did not destroy the “essential features” of Roman society, economy, and culture. It was only the advance of Islam in the seventh and early eighth centuries that isolated Western Europe from the Mediterranean and the eastern empire and brought the final demise of classical civilization in the West. Archaeological research, however, has shown this thesis to be largely incorrect. David Whitehouse writes, “Mediterranean civilization experienced a long process of change, in the course of which the old political and economic unity disintegrated. This process … was well advanced long before the seventh century.” Whitehouse, “Archaeology and the Pirenne Thesis,” in Charles Redman, ed., Medieval Archaeology: Papers of the Seventeenth Annual Conference of the Center for Medieval and Early Renaissance Studies (Binghamton, NY: State University of New York at Binghamton, 1989), 10. See also Richard Hodges and David Whitehouse, Mohammed, Charlemagne & the Origins of Europe: Archaeology and the Pirenne Thesis (London: Duckworth, 1983).
48. A leading advocate of these views is the historian Glen Bowersock of the Princeton Institute for Advanced Study. “Social, political, and intellectual reorganization was accomplished entirely within the framework of what had been there before,” he writes. “As far as the internal functioning of the Roman empire in the sixth century is concerned,” he goes on, “there is no clear indication of any substantial instability or depression in the social, economic, and political life of the time.” G. W. Bowersock, “The Dissolution of the Roman Empire,” in Yoffee and Cowgill, eds., The Collapse of Ancient States and Civilizations, 170–72.
49. The historian Chris Wickham writes, “Early medieval Italy was a very much simpler world than late Roman Italy.” Wickham, Early Medieval Italy: Central Power and Local Society, 400–1000 (Ann Arbor: University of Michigan Press, 1989), 27, 40–41. Says the archaeologist David Whitehouse, “the political fragmentation of the Roman empire was accompanied by a long process of economic decline and urban decay.” Whitehouse, “Archaeology and the Pirenne Thesis,” 6–7. On archaeological evidence, see also Hodges and Whitehouse, Mohammed, Charlemagne & the Origins of Europe.
50. On Roman and later lighting technology, see William Nordhaus, “Do Real-Output and Real-Wage Measures Capture Reality? The History of Lighting Suggests Not,” in The Economics of New Goods, Timothy Bresnahan and Robert Gordon, eds. (Chicago: University of Chicago Press, 1997), 29–66, especially 33.
51. Rein Taagepera has conducted the most important research on changes in the geographical area of historical empires. See Taagepera, “Growth Curves of Empires,” General Systems 13 (1968): 171–75; Taagepera, “Size and Duration of Empires: Systematics of Size,” Social Science Research 7 (1978): 108–27; Taagepera, “Size and Duration of Empires: Growth-Decline Curves, 3000 to 600 B.C.,” Social Science Research 7 (1978): 180–96; Taagepera, “Size and Duration of Empires: Growth-Decline Curves, 600 B.C. to 600 A.D.,” Social Science History 3, no. 3/4 (1979): 115–38; and Taagepera, “Expansion and Contraction Patterns of Large Polities: Context for Russia,” International Studies Quarterly 41 (1997): 475–504.
52. An exception is the historian Aurelio Bernardi, who writes, “Thus the fall of an immense State that had lasted a thousand years was completed in the course of not much more than half a century.” Bernardi, “The Economic Problems of the Roman Empire at the Time of Its Decline,” in Carlo Cipolla, ed., The Economic Decline of Empires (London: Methuen, 1970), 25.
53. This conclusion can be drawn from examining the graphs in Rein Taagepera, “Expansion and Contraction Patterns of Large Polities,” 482–84, and in Alexander Moytl, Imperial Ends: The Decay, Collapse, and Revival of Empires (New York: Columbia University Press, 2001), 41–45.
54. Some historians, however, have lately betrayed a distinct nostalgia for empires. For example, see Niall Ferguson, Colossus: The Rights of America’s Empire (New York: Penguin, 2004), especially chapter 5, “The Case for Liberal Empire,” 169–99.
55. General Accounting Office, Emerging Infectious Diseases: Asian SARS Outbreak Challenged International and National Responses (Washington, DC: GAO, April 2004), 4.
56. Arthur Koestler, The Sleepwalkers: A History of Man’s Changing Vision of the Universe (London: Hutchison & Co., 1959), 48.
1. Ian Stirling, Nicholas Lunn, and John Iacozza, “Long-Term Trends in the Population Ecology of Polar Bears in Western Hudson Bay in Relation to Climatic Change,” Arctic 52, no. 3 (September 1999): 294–306. Percentage changes in bear condition were calculated using figure 6.
2. While most polar bears hunt on the ice after freeze-up in the fall, pregnant females remain on shore to give birth to their cubs, usually around December. To ensure the health and survival of their cubs, the females must begin the long winter with as much body fat as possible.
3. Peter Clarkson and Doug Irish, “Den Collapse Kills Female Polar Bear and Two Newborn Cubs,” Arctic 44, no. 1 (March 1991): 83–84; and Ian Stirling and Andrew Derocher, “Possible Impacts of Climatic Warming on Polar Bears,” Arctic 46, no. 3 (September 1993): 240–45, especially 244.
4. Natalie Angier, “Built for the Arctic: A Species’ Splendid Adaptations,” New York Times, January 27, 2004, national edition, D1. While there is a general consensus among scientists and wildlife experts that global warming is disrupting polar bear ecology, some skeptics have challenged this consensus. For a summary of the debate, see Clifford Krauss, “Debate on Global Warming Has Polar Bear Hunting in Its Sights,” New York Times, May 27, 2002, national edition, A1.
5. Camille Parmesan and Gary Yohe, “A Globally Coherent Fingerprint of Climate Change Impacts across Natural Systems,” Nature 421, no. 6918 (January 2, 2003): 37–42; and Terry Root et al., “Fingerprints of Global Warming on Wild Animals and Plants,” Nature 421, no. 6918 (January 2, 2003): 57–60.
6. On sardine catches in Africa, see Dirk Verschuren, “The Heat on Lake Tanganyika,” Nature 424, no. 6950 (August 14, 2003): 731–32.
7. Andrew Blaustein and Pieter Johnson, “Explaining Frog Deformities,” Scientific American 288, no. 2 (February 2003): 60–65; and Stephen Buchmann and Gary Nabhan, The Forgotten Pollinators (Washington, DC: Island Press, 1996).
8. The Harvard ecologist E. O. Wilson writes, “We evolved here, one among many species, across millions of years, and exist as one organic miracle linked to others. The natural environment we treat with such unnecessary ignorance and recklessness was our cradle and nursery, our school, and remains our one and only home. To its special conditions we are intimately adapted in every one of the bodily fibers and biochemical transactions that give us life.” Edward O. Wilson, “The Bottleneck,” Scientific American 286, no. 2 (February 2002): 91.
9. Bjørn Lomborg, The Skeptical Environmentalist: Measuring the Real State of the World (Cambridge: Cambridge University Press, 2001).
10. Lomborg writes, “We will not lose our forests; we will not run out of energy, raw materials or water. We have reduced atmospheric pollution in the cities of the developed world and have good reason to believe that this will also be achieved in the developing world. Our oceans have not been defiled, our rivers have become cleaner and support more life. … Acid rain did not kill off our forests, our species are not dying out as many have claimed…. The problem of the ozone layer has been more or less solved. The current outlook on the development of global warming does not indicate a catastrophe.” Ibid., 329.
11. Lomborg simplistically extrapolates past trends into the future. He looks mainly at global averages, which often obscure key developments at the regional level. He frequently uses a resource’s price as an objective indicator of its scarcity, when in fact price often reflects a multitude of political, economic, and social factors that have little to do with underlying scarcity or abundance. And he underplays the possibility of nonlinear shifts in ecosystems, like the collapse of fisheries or a sudden climate flip. Lomborg is also breathtaking in his hypocrisy: he too manipulates statistics, uses evidence selectively, and employs straw-man argumentation—just like the worst environmental ideologue. “Every class of mistake of which he accuses environmentalists and environmental scientists,” writes John Holdren of Harvard University, “is in fact committed prolifically and indiscriminately in The Skeptical Environmentalist.” John Holdren, “A Response to Bjørn Lomborg’s Response to My Critique of His Energy Chapter,” Scientific American.com, April 15, 2002, 5. Available at http://www.scientificamerican.com/print_version.cfm?articleID=000DC658–9373–1CDA-B4A8809EC588EEDF.
12. See, for instance, Stuart Pimm and Jeff Harvey, “No Need to Worry about the Future,” review in Nature 414, no. 6860 (November 8, 2001): 149–50; Michael Grubb, “Relying on Manna from Heaven,” review in Science 294, no. 5545 (November 9, 2001): 1285–87; Douglas Kysar, “Some Realism about Environmental Skepticism: The Implications of Bjørn Lomborg’s The Skeptical Environmentalist for Environmental Law and Policy,” Ecology Law Quarterly 30 (2003): 223–80; and “Misleading Math about the Earth,” a compilation of critiques of Lomborg’s arguments by Stephen Schneider (on global warming), John Holdren (on energy), John Bongaarts (on population), and Thomas Lovejoy (on biodiversity), in Scientific American 286, no. 1 (January 2002): 61–71.
13. The charge that Lomborg sometimes engages in outright deceit is justified. To take one of many examples in The Skeptical Environmentalist, he claims that forest loss in the tropics is not nearly as severe as often claimed: the rate of loss is only 0.46 percent a year, he says, not 0.7 to 0.8 percent as widely reported. To support this claim, he refers to the Summary Report of The Global Forest Resources Assessment 2000 produced by the UN’s Food and Agriculture Organization (FAO) in 2001. But a close look at this document shows that he cites only the Assessment’s data from a satellite survey of tropical forests. He completely ignores the Assessment’s main conclusions about tropical forest loss, generated by combining the results of the satellite survey with a painstaking country-by-country on-the-ground inventory of forests. Based on these two methods, the FAO concluded that the rate of tropical forest loss during the 1990s was 0.73 percent a year, not significantly different from the previous decade’s rate. This conclusion appears in the Summary Report’s paragraphs immediately preceding the satellite data—so it’s impossible to miss. Moreover, the Summary Report’s abstract and the FAO’s annual survey, State of the World’s Forests 2001, cite only the combined results of the two methods, not the satellite data by themselves. So the only reasonable interpretation of Lomborg’s omission of the Assessment’s main findings is that he deliberately intended to mislead his readers. See Committee on Forestry, The Global Forest Resources Assessment 2000, Summary Report (Rome: FAO, 2001) available at ftp://ftp.fao.org/unfao/bodies/cofo/cof015/X9835e.pdf; and Food and Agriculture Organization, State of the World’s Forests 2001 (Rome: FAO, 2001), available at ftp://ftp.fao.org/docrep/fao/003/y0900e/y0900e00.pdf.
14. A classic discussion of our chronic denial of environmental problems is David Orr and David Ehrenfeld, “None So Blind: The Problem of Ecological Denial,” Conservation Biology 9, no. 5 (October 1995): 985–87.
15. I’m indebted to John Holdren for pointing out these stages to me, although the labels are mine.
16. “One of the great success stories of the recent half-century is … the remarkable progress the industrial societies have made, during a period of robust economic growth, in reversing the negative environmental impacts of industrialization.” Jack Hollander, The Real Environmental Crisis: Why Poverty, Not Affluence, Is the Environment’s Number One Enemy (Berkeley: University of California Press, 2003), 3.
17. “A Project to Grow Fish in Once-Polluted Boston Harbor Waters,” New York Times, December 28, 1997, national edition, 22.
18. Felicity Barringer, “California Air Is Cleaner, but Troubles Remain,” New York Times, August 3, 2005, national edition, A1.
19. This is often called the Environmental Kuznets Curve (EKC) hypothesis. Simon Kuznets, one of the twentieth century’s great economists, proposed that a country’s income inequality rises and subsequently declines as its average income rises. The EKC hypothesis, although not proposed by Kuznets himself, postulates that pollution and other forms of environmental damage will also rise and then decline as average income rises. Although the hypothesis has become a staple of conservative commentary on environmental issues, researchers have shown that it’s invalid in important respects. For a discussion and critique, see Cutler Cleveland and Matthias Ruth, “Indicators of Dematerialization and the Materials Intensity of Use: A Critical Review with Suggestions for Future Research,” Journal of Industrial Ecology 2, no. 3 (Summer 1998): 15–50. See also Dale Rothman and Sander de Bruyn, eds., “The Environmental Kuznets Curve,” special issue of the journal Ecological Economics 25 (1998). Evidence in favor of the EKC is presented in Gene Grossman and Alan Krueger, “Economic Growth and the Environment,” NBER Working Paper #4634, National Bureau of Economic Research (February 1994). The quotation from Wilfred Beckerman can be found in Beckerman, “Economic Growth and the Environment: Whose Growth? Whose Environment?” World Development 20, no. 4, Special Issue (April 1992): 481–96.
20. Although in recent decades most companies have sharply reduced resource inputs to production, they’ve invariably done so to reduce costs and not to reduce their environmental impact.
21. National Association of Home Builders, “New Home Characteristics,” Housing 2004: Facts, Figures & Trends (Washington, DC: NAHB, 2004), 11; Joy Nielsen and Barry Popkin, “Patterns and Trends in Food Portion Sizes, 1977–1998,” Journal of the American Medical Association 289, no. 4 (January 22, 2003): 450–53.
22. Matthew Wald, “Oil Crises: Which One Is Worse,” New York Times, Week in Review, April 21, 2002, national edition, 4. According to the U.S. Bureau of Transportation Statistics, in 2001 there were about 230 million registered cars, trucks, and motorcycles in United States (see the data table at http://www.bts.gov/publications/national_transportation_statistics/2002/html/table_automobile_profile.html).
23. For a detailed treatment of the factors that influence the environmental impact of such migrations, see Richard Bilsborrow, “Migration, Population Change, and the Rural Environment,” in Environmental Change and Security Program, Report 8 (Washington, DC: Woodrow Wilson International Center for Scholars, Environmental Change and Security Program, 2002), available at http://www.wilsoncenter.org/topics/pubs/Report_8_BIlsborrow_article.pdf.
24. The most comprehensive assessment of humankind’s impact on the global environment is the Millennium Ecosystem Assessment, an international work program sponsored and coordinated by the United Nations and “designed to meet the needs of decision makers and the public for scientific information concerning the consequences of ecosystem change for human well-being and options for responding to those changes.” Almost two thousand authors from nearly one hundred countries have been involved in preparing this assessment, which has been summarized in fifteen reports. Further information is available at http://www.maweb.org//en/index.aspx.
25. William Ruddiman, however, puts the date much earlier, about eight thousand years ago, reckoning that large-scale deforestation for agriculture in Eurasia caused, around that time, a fundamental shift in Earth’s carbon and methane cycles. See W. F. Ruddiman, “The Anthropogenic Greenhouse Era Began Thousands of Years Ago,” Climatic Change 61 (2003): 261–93; Betsy Mason, “The Hot Hand of History,” Nature 427, no. 6975 (February 12, 2004): 582–83; and Paul Crutzen, “Geology of Mankind,” Nature 415, no. 6867 (January 3, 2002): 23.
26. Robert Berner, “The Long-term Carbon Cycle, Fossil Fuels and Atmospheric Composition,” Nature 426, no. 6964 (November 20, 2003): 323–26.
27. David Schimel and David Baker, “The Wildfire Factor,” Nature 420, no. 6911 (November 7, 2002): 29–30; and Susan Page et al., “The Amount of Carbon Released from Peat and Forest Fires in Indonesia during 1997,” Nature 420, no. 6911 (November 7, 2002): 61–65.
28. Andrew Revkin, “Sunken Fires Menace Land and Climate,” New York Times, January 15, 2002, national edition, D1. Estimates of the quantity of coal burned by these fires are prone to large errors because they require multiple assumptions about such things as the average thickness of the coal seams, the rate of combustion, and the combustion temperature.
29. See chapter 6 in Vaclav Smil, Cycles of Life: Civilization and the Biosphere (New York: Scientific American Library, 1997), 141–69.
30. Reactive or fixed nitrogen (as opposed the form of nitrogen that’s abundant in air) allows plants to build proteins and so is essential to all higher life. There are large uncertainties in estimates of total natural nitrogen fixation: although the range is commonly put at 90 to 100 million tons, the figure could range as high as 250 million tons. Smil, The Earth’s Biosphere, 248–51; and Smil, personal correspondence with the author, March 28, 2004.
31. Robert May, “Melding Heart and Head,” Our Planet (2000), available at http://www.ourplanet.com/imgversn/111/may.html; and Vaclav Smil, “Global Population in the Nitrogen Cycle,” Scientific American 277, no. 1 (July 1997): 76–81.
32. Nicola Nosengo, “Fertilized to Death,” Nature 425, no. 6961 (October 30, 2003): 894–95.
33. United Nations Environment Programme, Global Environment Outlook 2003 (Nairobi: UNEP, 2003). See also Emily Matthews and Allen Hammond, Critical Consumption Trends and Implications: Degrading Earth’s Ecosystems (Washington, DC: World Resources Institute, 1999), 11–30; and David Malakoff, “Death by Suffocation in the Gulf of Mexico,” Science 281, no. 5374 (July 10, 1998): 190–92.
34. “Humans are now an order of magnitude more important at moving sediment than the sum of all other natural processes operating on the surface of the planet.” Bruce Wilkinson, “Humans as Geologic Agents: A Deep-Time Perspective,” Geology 33, no. 3 (March 2005): 161–64. See also B. L. Turner et al., eds., The Earth As Transformed by Human Action: Global and Regional Changes in the Biosphere over the Past 300 Years (Cambridge: Cambridge University Press with Clark University, 1990), 13.
35. Vitousek and his colleagues estimate that humans have transformed about a third to a half of Earth’s total land surface, while Smil estimates that we have “strongly or partially imprinted” some 55 percent of non-glaciated land. See Peter Vitousek, Harold Mooney, Jane Lubchenco, and Jerry Melillo, “Human Domination of Earth’s Ecosystems,” Science 277, no. 5325 (July 25, 1997): 494–9; and Vaclav Smil, The Earth’s Biosphere: Evolution, Dynamics, and Change (Cambridge, MA: MIT, 2002), 239–40.
36. Vitousek et al., “Human Domination,” 498.
37. James Gustave Speth, “A New Green Regime,” Environment (Spring 2002): 18.
38. Peter Vitousek, Paul Ehrlich, Anne Ehrlich, and Pamela Matson, “Human Appropriation of the Products of Photosynthesis,” BioScience 36, no. 6 (June 1986): 368–73. The authors examine “human impact on the biosphere by calculating the fraction of net primary production (NPP) that humans have appropriated. NPP is the amount of energy left after subtracting the respiration of primary producers (mostly plants) from the total amount of energy (mostly solar) that is fixed biologically.” For a more recent analysis that uses an alternative methodology but arrives at similar conclusions, see Marc Imhoff et al., “Global Patterns in Human Consumption of Net Primary Production,” Nature 429, no. 6994 (June 24, 2004): 870–73. See also, Helmut Habert, “Human Appropriation of Net Primary Production as an Environmental Indicator: Implications for Sustainable Development,” Ambio 26, no. 3 (May 1997): 143–46.
39. Vitousek et al., “Human Appropriation,” 372. The date of presumed plant diversification was derived from the discussion in Paul Kenrick and Peter R. Crane, chapter 7, “Early Evolution of Land Plants,” The Origin and Early Diversification of Land Plants: A Cladistic Study (Washington, DC: Smithsonian Institution Press, 1997), 226–310.
40. Food and Agriculture Organization, “Wood Energy: Promoting Sustainable Wood Energy Systems (SWES),” report available at http://www.fao.org/forestry/foris/webview/energy/index.jsp?siteId=3281&langId=1.
41. In 2001, the United Nations Food and Agriculture Organization (FAO) released the results of the Global Forest Resources Assessment 2000, which provided a comprehensive account of global forest loss based on a country-by-country inventory and a satellite survey. The results can be found in Committee on Forestry, The Global Forest Resources Assessment 2000, Summary Report (Rome: FAO, 2001) available at ftp://ftp.fao.org/unfao/bodies/cofo/cof015/X9835e.pdf; and at FAO, State of the World’s Forests 2001 (Rome: FAO, 2001), available at ftp://ftp.fao.org/docrep/fao/003/y0900e/y0900e00.pdf.
42. Currently, forest loss is concentrated in certain countries. In Asia, these include Indonesia, Malaysia, Thailand, Myanmar, and the Philippines; in Africa, forests are disappearing at a high rate in Zambia, Malawi, and Zimbabwe and across a swath of West African countries from Nigeria through Guinea; and in Latin America, deforestation is severe in Brazil, Argentina, and Mexico. On virgin forests, see James Gustave Speth, “Recycling Envronmentalism,” Foreign Policy (July/August 2002): 74–75; and on mangroves, see FAO, “Part 1: The Situation and Developments in the Forest Sector,” State of World Forests 2003 (Rome: FAO, 2003), available at http://www.fao.org/DOCREP/005/Y7581E/y7581e04.htm#P0_4.
43. “Making Mincemeat out of the Rainforest,” Environment 46, no. 5 (June 2004): 5. Larry Rohter, “Loggers, Scorning the Law, Ravage the Amazon,” New York Times, October 16, 2005, national edition, 1; Rohter, “Deep in Amazon, Vast Questions about Climate,” New York Times, November 4, 2003, national edition, D1; and Rohter, “Amazon Forest Is Still Burning, Despite Pledges,” New York Times, August 23, 2002, national edition, A1.
44. Raymond Bonner, “Indonesia’s Forests Go Under Ax for Flooring,” New York Times, September 13, 2002, national edition, A3; and Jane Perlez, “Forests in Southeast Asia Fall to Prosperity’s Ax,” New York Times, April 29, 2006, national edition, A1.
45. Vitousek et al., “Human Domination,” 496–97; and Smil, The Earth’s Biosphere, 246.
46. United Nations Educational, Scientific, and Cultural Organization, The UN World Water Development Report Water for People, Water for Life (Paris: UNESCO, 2003), 10; available at http://www.unesco.org/water/wwap/wwdr/table_contents.shtml.
47. Tom Gardner-Outlaw and Robert Engleman, Sustaining Water, Easing Scarcity: A Second Update (Washington, DC: Population Action International, 1997).
48. “Outside China, the world’s population has been increasing more quickly than the total food fish supply from production, resulting in a decreased global per capita fish supply from 14.6 kg in 1987 to 13.1 kg in 2000.” Food and Agriculture Organization, The State of World Fisheries and Aquaculture), “Part 1: World Review of Fisheries and Aquaculture” (Rome: FAO, 2002), available at http://www.fao.org/docrep/005/y7300e/y7300e04.htm#P5_111. See also Figure 2 in Reg Watson, “The Sea Around Us Project Runs a Successful Marine Symposium at AAAS,” The Sea Around Us Project Newsletter 11 (May/June 2002): 4, available at http://saup.fisheries.ubc.ca/Newsletters/Issue11.pdf.
49. Ecologists speak of the upper “trophic levels” of the fisheries ecosystem. Trophic levels are “ranked according to how many steps they are removed from the primary producers at the base of the web, which generally consists of phytoplanktonic algae.” Daniel Pauly and Reg Watson, “Counting the Last Fish,” Scientific American 289, no. 1 (July 2003): 43–47, especially 45; and Daniel Pauly et al., “Fishing Down Marine Food Webs,” Science 279, no. 5352 (February 6, 1998): 860–63.
50. Ransom Myers and Boris Worm, “Rapid Worldwide Depletion of Predatory Fish Communities,” Nature 423, no. 6937 (May 15, 2003): 280–83. For a critical response, see John Hampton et al., “Fisheries: Decline of Pacific Tuna Populations Exaggerated?” Nature 434, no. 7037 (April 28, 2005): E1-E2, and the response by Myers and Worm in the same edition. Also see Andrew Revkin, “Atlantic Sharks Found in Rapid Decline,” New York Times, January 17, 2003, national edition, A16; and Andrew Revkin, “Commercial Fleets Slashed Stocks of Big Fish by 90%, Study Says,” New York Times, May 15, 2003, national edition, A1.
51. Jeffrey Hutchings, “The cod that got away,” Nature 428, no. 6986 (April 29, 2004): 899–900.
52. Villy Christensen et al., “Hundred-year Decline of North Atlantic Predatory Fishes,” Fish and Fisheries 4, no. 1 (March 2003): 1. See also Craig Smith, “North Sea Cod Crisis Brings Call for Nations to Act,” New York Times, November 7, 2002, national edition, A3.
53. “Trawlers trailing dredges the size of football fields have literally scraped the bottom clean,” write Daniel Pauly and Reg Watson of the University of British Columbia. These practices harvest “an entire ecosystem—including supporting substrates such as sponges—along with the catch of the day. Farther up the water column, long lines and drift nets are snagging the last sharks, swordfish and tuna. The hauls of these commercially desirable species are dwindling, and the sizes of individual fish being taken are getting smaller; a large number are even captured before they have time to mature.” Pauly and Watson, “Counting the Last Fish,” 43–47.
54. These practices have caused “the wholesale destruction of many deep-water environments,” says Callum Roberts, a marine biologist at England’s University of York. He points to the example of orange roughy, an exotic deep-water fish that was once abundant in the waters off Australia and New Zealand. In just a few years in the 1970s and 1980s, trawlers—some of which could land sixty metric tons of fish in as little as twenty minutes—depleted stocks by 80 percent. Because individuals in this species grow slowly and can be seventy to one hundred years old, the devastated stocks won’t recover for decades, if ever. And the assault has affected much more than orange roughy: “In the sea mounts where the orange roughy is hunted, there were once sea fans, black corals, hydroids, invertebrates. Yet these centers of life have frequently been stripped down to the rock. … On land, if we thought we would destroy an entire forest just to catch a few deer, there’d be an outcry. Yet we are doing something like that in the deep sea.” Claudia Dreifus, “A Biologist Decries the ‘Strip Mining’ of the Deep Sea,” New York Times, March 5, 2002, national edition, D4. See also Jennifer Devine, Krista Baker, and Richard Haedrich, “Deep-Sea Fishes Qualify as Endangered,” Nature 439, no. 7072 (January 5, 2006): 29.
55. Rosamond Naylor et al., “Effect of Aquaculture on World Fish Supplies,” Nature 405, no. 6790 (June 29, 2000): 1017–24; and Kendall Powell, “Eat Your Veg,” Nature 426, no. 6965 (November 27, 2003): 378–79.
56. “[Human] demand may well have exceeded the biosphere’s regenerative capacity since the 1980s. According to this preliminary and exploratory assessment, humanity’s load corresponded to 70 percent of the capacity of the global biosphere in 1961, and grew to 120 percent in 1999.” Mathis Wackernagel et al., “Tracking the Ecological Overshoot of the Human Economy,” Proceedings of the National Academy of Sciences of the United States of America 99, no. 14 (July 9, 2002): 9266–71.
57. Tim Wiener, “In Mexico, Greed Kills Fish by the Seafull,” New York Times, April 10, 2002, national edition, A1.
58. Jessica Tuchman Mathews, “Redefining Security,” Foreign Affairs 68, no. 2 (1989): 168.
59. Tim Wiener, “Life Is Hard and Short in Bleak Villages of Haiti,” New York Times, March 14, 2004, national edition, 1.
60. Asian Development Bank, Asian Environment Outlook 2001 (Manila: ADB, 2001), xiii.
61. For an analysis of the links between environmental stress and violent conflict, including details on many of the cases mentioned in this paragraph, see Thomas Homer-Dixon, Environment, Scarcity, and Violence (Princeton: Princeton University Press, 1999). See also Colin Kahl, States, Scarcity, and Civil Strife in the Developing World (Princeton: Princeton University Press, 2006); and Richard Cincotta, Robert Engelman, and Daniele Anastasion, The Security Demographic: Population and Civil Conflict after the Cold War (Washington, DC: Population Action International, 2003).
62. UN Integrated Regional Information Networks (IRIN), November 20, 2001.
63. Tim Weiner, “87 Orphans Will Be Told of the Killers Next Door,” New York Times, June 4, 2002, national edition, A4.
64. Howard French, “Riots in Shanghai Suburb as Pollution Protest Heats Up,” New York Times, July 19, 2005, national edition, A5.
65. Philip Howard, Environmental Scarcities and Conflict in Haiti: Ecology and Grievances in Haiti’s Troubled Past and Uncertain Future (Ottawa: Canadian International Development Agency, 1998); and Ginger Thompson, “A New Scourge Afflicts Haiti: Kidnappings,” New York Times, June 6, 2005, national edition, A1.
66. Kahl, “Green Crisis, Red Rebels: Communist Insurgency in the Philippines,” in States, Scarcity, and Civil Strife, 65–116; and Seth Mydans, “Communist Revolt Is Alive, and Active, in the Philippines,” New York Times, March 26, 2003, national edition, A3.
67. Jean Bigagaza, Carolyne Abong, and Cecile Mukarubuga, “Land Scarcity, Distribution and Conflict in Rwanda,” chapter 2 in Lind and Sturman, eds., Scarcity and Surfeit: The Ecology of Africa’s Conflict (Pretoria: Institute of Security Studies, 2002), 51–84; and James K. Gasana, “Natural Resource Scarcity and Violence in Rwanda,” in Richard Matthew, Mark Halle, and Jason Switzer, eds., Conserving the Peace: Resources, Livelihoods and Scarcity (Winnipeg: International Institute of Sustainable Development, 2002), 199–246.
68. Marc Lacey, “In Sudan, Militiamen on Horses Uproot a Million,” New York Times, May 4, 2004, national edition, A1.