The real tragedy of the commons

Philosophy and Public Affairs

Volumn 30, Issue 4, 2001, Pages 387-416

  Gardiner, Stephen M ^a  

^a NONE

Author keywords

[No Author keywords available]

Indexed keywords

ANALYTICAL APPROACH; ARTICLE; DEVELOPED COUNTRY; DEVELOPING COUNTRY; ENVIRONMENT; GENETICS AND REPRODUCTION; GREENHOUSE EFFECT; HUMAN; HUMAN RELATION; INTERNATIONAL COOPERATION; PERSUASIVE COMMUNICATION; PHILOSOPHICAL APPROACH; POLLUTION; POPULATION DYNAMICS;

ANALYTICAL APPROACH; GENETICS AND REPRODUCTION; PHILOSOPHICAL APPROACH;

COERCION; DEVELOPED COUNTRIES; DEVELOPING COUNTRIES; ENVIRONMENT; ENVIRONMENTAL POLLUTION; GREENHOUSE EFFECT; HUMANS; INTERGENERATIONAL RELATIONS; INTERNATIONAL COOPERATION; POPULATION CONTROL;

EID: 0035470724     PISSN: 00483915     EISSN: 10884963     Source Type: Journal    
DOI: 10.1111/j.1088-4963.2001.00387.x     Document Type: Article

References (94)

1. "Tragedy of the Commons," Science 162 (1968): 1243-48;
2. "Living in a Lifeboat," Bioscience 24 (1974): 561-68.
3. See also Living Within Limits (Cambridge: Cambridge University Press, 1993);
4. The Ostrich Factor: Our Population Myopia (Oxford: Oxford University Press, 1999).
5. Some estimation of the influence of Hardin's work and the esteem with which it is held in the scientific community can be found in Joanna Burger and Michael Gochfield, "The Tragedy of the Commons 30 Years Later," Environment (December 1998): 4-27;
6. the responses in "The Tragedy of the Commons Revisited," Environment (March 1999): 4-5, 45;
7. and Hardin's "Extensions of 'The Tragedy of the Commons'," Science 280 (1998): 682-83. Burger and Gochfield include a graph of the citation index from 1968 to 1997 showing persistent levels of over 100 citations per year among natural and social scientists.
8. Hardin's work has, of course, been criticized before, but I have not found the criticism I will make in the literature. First, most of the criticism is empirical, especially that offered by proponents of a benign demographic transition hypothesis, who maintain that population will be curbed by development. Unfortunately, valuable though it is, this work does not directly address Hardin's main argument, which is not empirical but theoretical. Second, much of the theoretical criticism of Hardin revolves around his metaphors in "Lifeboat Ethics," not those in "Tragedy of the Commons." For a good discussion of the major views and their weaknesses, see Jesper Ryberg, "Population and Third World Assistance," Journal of Applied Philosophy 14 (1997): 207-19.
9. The climate change problem is a useful illustration for two reasons: because it seems to be the most serious environmental problem we face at present; and because something like the same incentive structure appears to some degree in other environmental problems.
10. United Nations, Department of Economic and Social Affairs, Population Division, 1998 Update (http://www.census.gov//ipc//www/worldpop.html).
11. Bill McKibben, "Reaching the Limit," New York Review of Books (May 29, 1997).
12. The U.S. Bureau of Census estimates the peak to have been in 1962 and 1963 at 2.19 percent per year.
13. This is not to say that the issue is one of whom to blame, in the moral sense. Hardin thinks blaming misses the point. In "Lifeboat," he says, "the concepts of blame and punishment are irrelevant. The question is, what are the operational consequences of establishing a world food bank?" (p. 563). In Living Within Limits, this is on his assumption that "each human being, like every other animal, is genetically programmed to seek its own good," so that "[t]he tragedy is brought on not by individual sin ('greed'), but by the system itself" (p. 218).
14. "Tragedy," p. 1244; emphasis added.
15. "Tragedy," Ibid., p. 1246;
16. Ostrich, p. 145.
17. "Lifeboat," p. 564.
18. "Tragedy," p. 1244.
19. Repeated in Living Within Limits, pp. 217-18.
20. See Nick Griffin, "Lifeboat USA, Part 1," International Journal of Moral and Social Studies 3 (1988): 230-31.
21. The second feature also poses difficulties for Hardin. Environmental problems associated with population growth can impact resources at various levels (local, national, regional and global). Presumably, then, the best candidate for a single common resource is the biosphere as a whole. But Hardin does not take this approach. Instead, in "Lifeboat," he rejects a "spaceship earth" metaphor in favor of speaking of the rich countries as individual lifeboats that should defend themselves against the lifeboats of the poor countries. But it is not clear what the ecological grounds could be for taking individual countries as single common resources. For further criticisms, see William W. Murdoch and Allen Oaten, "Population and Food: Metaphors and the Reality," Bioscience 25 (1975);
22. reprinted in Louis Pojman, Environmental Ethics, 2d ed. (Belmont, Calif.: Wadsworth, 1998), 357-61.
23. The title and illustration are attributed to Albert Tucker, who used them to popularize ideas developed by Merrill Flood and Melvin Dresher in investigating global nuclear strategy. For more information, see Stephen Kuhn, "The Prisoner's Dilemma," Stanford Encyclopedia of Philosophy, http://setis.library.usyd.edu.au/stanford/entries/prisoner-dilemma/#Bib'
24. But neither of us can get there as things stand. Suppose one of us thinks, It's a prisoner's dilemma, so we should not confess. Then, the other person knows that we know this. But if he thinks we are not going to confess, the rational thing for him to do is to confess, since this gives him a better outcome. Remember that the previous reasoning showed that a prisoner should confess, no matter what the other prisoner does.
25. The prisoner's dilemma structure is interesting for both theoretical and practical reasons. The theoretical reason is that it involves a paradox of rationality. It shows that in some situations, individuals reasoning purely on the basis of self-interest can be led to make decisions that are suboptimal in terms of self-interest. (Strictly-speaking, the problem does not depend on self-interested motivation per se, but might arise for any value system with a similar structure, including some moral views. See Derek Parfit, Reasons and Persons [Oxford: Oxford University Press, 1984], pp. 55-56, 95-110.) The practical reason is that there are real world situations that have this structure.
26. Ryberg also argues that even if Hardin is right about the severity of the problem, it may not necessitate his solutions. Ryberg's argument relies on the idea that aid to the "overpopulated" countries coupled with regulation of population via famine and environmental disaster may still be best on Hardin's consequentialist grounds. See Ryberg, pp. 212-15. Hence, he disputes Hardin's empirical claims about the overall results of the prisoner's dilemma. By contrast, I take issue with Hardin's assumptions about what follows from the dilemma situation itself.
27. A principle of beneficence may be conceived of as either a principle of moral goodness (or virtue), or as a moral requirement. Here I directly intend the former, as beneficence is less controversial as a moral ideal (say, of charity), than as a moral requirement. But I also believe that the weak principle I have in mind is plausible as a requirement.
28. For example, some might argue that, in withholding aid, the rich countries seem to treat the people who starve as a result disrespectfully. For the starving seem to be treated in ways to which they could not in principle consent, and so can be conceived of as being coerced. (One might also say that they are thereby used by the rich as a means to solving a wider problem.) Hence, their actions conflict with major tenets of Kantian (and arguably commonsense) morality, which claim we should not treat others in ways to which we could not in principle consent, and that we should never treat them merely as a means. These claims are, of course, controversial, even amongst Kantians. But an approach to aid problems which makes moves of this sort has been defended by Onora O'Neill, "Ending World Hunger" in Tom Regan, ed., Matters of Life and Death, 3d ed. (Belmont, Calif.: Wadsworth, 1993),
29. and Faces of Hunger: An Essay on Poverty, Justice, and Development (London: Allen & Unwin, 1985).
30. In the original standard 'tit for tat' solutions to the prisoner's dilemma, the second and third strategies fit together. Robert Axelrod reported that "the two requisites for cooperation to thrive are that the cooperation be based on reciprocity, and that the shadow of the future is important enough to make this reciprocity stable." (Axelrod, The Evolution of Cooperation [New York: Basic Books, 1984];
31. selection reprinted in Ethics, Peter Singer, ed. [Oxford: Oxford University Press, 1994], pp. 88-92 at p. 90.) For egoists, these conditions hold when there is prolonged interaction over time and where this interaction holds the promise of great benefits to both sides.
32. For an overview, see Andrew Hacker, "The Case Against Kids," New York Review of Books, vol. 47, no. 19 (November 30, 2000): 12-18.
33. Hardin says, "Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons," ("Tragedy," p. 1244, emphasis added);
34. about the population problem in particular he says, "the individual benefits as an individual from his ability to deny the truth [about the population tragedy] even though society as a whole, of which he is a part, suffers" ("Tragedy," p. 1244).
35. Hardin tends to speak in terms of "overbreeding," and seems to mean by this 'having as many healthy, surviving children as possible'. But his general argument requires only the more modest 'have a size of family above replacement level', and this is what I intend here. (I have avoided the use of 'breeding' as this term may seem offensive, and in any case encourages the animalistic connotations Hardin tries to give human behavior, connotations I resist below.)
36. The North American population figures are complicated by large immigration to both the United States and Canada. Without immigration, North America is likely to be slightly below replacement.
37. It is not true even in those nations officially in favor of more rather than fewer children. For example: Italy is officially Catholic; but nineteenth-century Italy had a fertility rate of five children per woman; but now it is down to significantly below that necessary for replacement. Indeed, the United Nations predicts very substantial immigration will be necessary to maintain its current population.
38. United Nations, 1998 Update. This data is used by optimists about population in support of their view that there will be a benign demographic transition to lower total population. The pessimists may argue that these declines are coming too late (and they may be right). But this does not help Hardin's argument, for this is an empirical question, to be answered by the data. But Hardin doesn't provide any data. He provides a conceptual argument to show that the population problem is a prisoner's dilemma, and that coercion is required.
39. For a good discussion of the data, see Elizabeth Willot, "Population Trends," in David Schmidtz and Elizabeth Willot, eds., Environmental Ethics: What Really Matters, What Really Works (Oxford: Oxford University Press, 2001).
40. A major cause of the problem seems to be (a) that these societies have no universal social security systems, and (b) that women are effectively relieved of all responsibilities' for their own family when they marry. This tends to make the rationality of having a child depend on its sex, and perhaps the rationality of having an additional child depend on the sex of the preceding children. See Celia W. Dugger, "Modern Asia's Anomaly: The Girls Who Don't Get Born," The New York Times, Week in Review. Sec. 4 (May 6, 2001): 4.
41. The issue is discussed in depth by Amartya Sen, "Missing Women," British Medical Journal 304 (March 7, 1992): 587;
42. and Development as Freedom, (New York: Anchor, 1999), chap. 8.
43. Hardin seems to realize this. He says that the independent herdsman "dare not refrain" from overloading the commons, because if he did so he would "suffer more" than a "selfish" one who does overgraze ("Lifeboat," p. 562);
44. furthermore, if he did refrain from overgrazing, the herdsman would be (correctly) condemned as a "simpleton" ("Tragedy," p. 1246).
45. "Tragedy," p. 1246; emphasis in original. As is often noted, this seems to be an inaccurate description of the motivation of those in above-replacement countries. People in some societies have reason to have lots of children because there is no one else to look after them when they become old and there is high infant mortality. This makes it risky not to have lots of children, from the point of view of self-interest. This is actually worse than a prisoner's dilemma situation. For here the parents are likely not to prefer the constrained outcome, because they fear abandonment in old age more than general population problems.
46. There is also a question about whether one can make sense of biological interests in evolutionary terms (and also, perhaps, whether one can make sense of the notion of biological interests). Such an approach is tried by Gary Varner, In Nature's Interests?: Interests, Animal Rights, and Environmental Ethics (Oxford: Oxford University Press, 1998). But note that even Varner believes that individuals have psychological interests in addition to their biological interests, and that the psychological interests trump the biological.
47. "Tragedy," p. 1246.
48. That is, we would expect people already to have the desire for as many children as would maximize the chance of the genes being passed on. Against this, Hardin would presumably argue that the historical natural pruning had an effect on reproductive motivation, but one which is being undermined by the more recent welfare state and foreign aid programs. But here it is worth pointing out (a) that those countries without the welfare state have sustained high birth rates rather than held them back, and (b) that the decline in birth rates has occurred in rich countries even given the introduction of welfare. (Against [b], Hardin might argue that it is too early to tell what will happen in these countries, given that welfare is fairly recent; but still the empirical evidence does not look promising for him.)
49. Determining the carrying capacity is a difficult and extremely value-laden business, which raises philosophical issues of its own. For a helpful discussion, see Joel E. Cohen, How Many People Can the Earth Support? (New York: Norton, 1995), chap. 12, and app. 3 and 4.
50. See Griffin, "Lifeboat," pp. 223-4.
51. Global energy consumption rose from 21 to 318 exajoules between 1900 and 1988 (See William C. Clark, in Managing Planet Earth (New York: Freeman, 1990), p. 87.
52. Bill McKibben reports that per capita consumption had risen from less than 1 megawatt-hour per person in 1800 to 19 megawatt hours per person in 1989 (McKibben, The End of Nature [New York: Anchor, 1989], p. 2).
53. For example, in 1997, India and China had commercial energy use per capita of 479 and 907 kg of oil equivalent respectively, compared to 3, 863 and 8,079 for the United Kingdom and United States respectively. (See World Bank, World Development Indicators 2000.) Hardin recognizes that energy consumption per capita is a useful partial measure of quality of life. He also points out the sharp difference between figures for developed and less developed countries. But he refused to see this as a global problem. Instead, he argues for a localizing principle: that parochial distribution of resources should be matched by parochial consumption; and so sees the problem as a local one. (For example, he all but suggests that Bangladesh should reduce its population from 104 million to 2.7 million, rather than bemoan its lack of resources.) But there are two problems for Hardin here.
54. First, his defense of the principle ("there must be some sort of fragmentation of administrative tasks") is too weak either to justify the principle itself, or the conclusions he is prepared to draw from it. Second, Hardin admits that the principle does not apply to air and water, where a global approach is needed. But, as I shall stress below, the most serious environmental problems caused by current energy consumption involve atmospheric pollution, and so are global. (See Hardin "Cultural Carrying Capacity: a Biological Approach to Human Problems," Bioscience 36 (1986): 599-606, esp. 602-5.)
55. Future generations are often defined as those future people whom those presently alive will not live to meet (see, for example, Avner de-Shalit, Why Posterity Matters: Environmental Policies and Future Generations [London: Routledge, 1995], p. 138). For the sake both of simplicity, and of making clear the fundamental dynamics, I follow that usage here. However, 'future generations' is also often used to refer to those not presently alive, and it is important to emphasize that many of the points I will make apply in a more nuanced way to this less restricted notion. This is because the crucial issue is not when those who will live when we have gone appear, but the extent of our present concern for their well-being. (This is what gives a point even to the more restrictive use of the term "future generations.") Indeed, it is worth noting that much of what is said about future people in the restricted sense applies not only to future people in the less restricted sense, but also (in a graduated way) to people already presently alive. For even when there is overlap, and we care about the well-being of at least some of the people who remain after we are dead, that concern tends to be less than our concern for people around now (even when the same people are at issue) and to decline over temporal distance. (Such issues are important to a full account of the dynamics of the global warming problem, since there one would want to say more about the medium-range effects of climate change. But here I am offering only a basic outline, for illustrative purposes.)
56. 2 emissions. (This is especially so because, even if the short-term future impact of climate change is significant, this will be caused by past emissions, and so is warming to which the present generation is already committed through the action of past generations.)
57. I leave aside the philosophical problem identified by Derek Parfit as the Non-Identity Problem. See Parfit, Reasons and Persons, chap. 16.
58. But note than even Parfit thinks that we can carry on talking in terms of harms to future generations (Parfit, Reasons and Persons, Ibid., p. 367).
59. They might continue certain traditions and projects. See John O'Neill, "Future Generations: Present Harms," Philosophy 68 (1993): 35-51.
60. Perhaps it could be weaker. Perhaps all that is required is that some generation capable of making a difference make the sacrifice. Still, the theoretical problem remains. Presumably it is to be resolved at least in part by appeal to purely altruistic moral reasons.
61. Perhaps the point can be made clearer by looking at the preference structures which underlie the tragic situation. The intergenerational problem begins with a prisoner's dilemma structure: 1st preference: I pollute, previous generation does not. 2nd preference: Neither I nor previous generation pollutes. 3rd preference: I pollute, previous generation pollutes. 4th preference: I don't pollute, previous generation pollutes. But for the first generation capable of serious overpollution, this becomes simply: 1st preference: I pollute. 2nd preference: I don't pollute. So, this fixes the third option for the next generation, and so on for subsequent generations.
62. Climate change is explicitly described as a prisoner's dilemma by Marvin S. Sooros, The Endangered Atmosphere: Preserving a Global Commons (Columbia, S.C.: University of South Carolina Press, 1997); pp. 260-261.
63. It seems to be implicit in many other analyses. By contrast, Jeremy Waldron makes the case for a Battle of the Sexes in an unpublished research paper kindly supplied to me by an anonymous referee for this journal. (Waldron, "Who is to Stop Polluting? Different Kinds of Free-Rider Problem," June-July 1990.
64. A Contribution to a project Ethical Guidelines for Global Bargains undertaken by the Program on Ethics and Public Life, Cornell University with support from the Rockefeller Foundation. Waldron is applying a general approach to collective action problems put forth by Jean Hampton, "Free-Rider Problems in the Production of Collective Goods," Economics and Philosophy 3 [1987]: 245-73;
65. and Hobbes and the Social Contract Tradition [Cambridge: Cambridge University Press, 1986].)
66. The Battle of the Sexes analysis is also briefly suggested by some remarks of Nick Mabey, Stephen Hall, Claire Smith and Sujata Gupta, Argument in the Greenhouse: The International Economics of Controlling Global Warming (London: Routledge, 1997), pp. 356-59; 409-10;
67. and, for the specific issue of ratification of the Kyoto Protocol, Scott Barrett, "Political Economy of the Kyoto Protocol," Oxford Review of Economic Policy 14 (1998): 20-39; 36-37.
68. I hope to pursue the issues in more detail, and as applied to the Kyoto Protocol in particular, in a future paper tentatively entitled "The Global Warming Tragedy." Some discussion of the Kyoto context is to be found in Barrett, "Political Economy."
69. There are two basic reasons why the structure of the intragenerational problem is unclear. First, solving the problem requires resolving a number of other collective action problems that are subordinate, or otherwise closely related, to it. Second, because of the uncertainty surrounding the magnitude and distribution of the various costs and benefits of climate change, the dynamics of the intragenerational and related problems are all subject to considerable uncertainty.
70. The writers noted above are all concerned with countries. But I begin with individuals for the sake of simplicity, since I believe that a prisoner's dilemma analysis would be widely accepted at that level. I make a case for extending the analysis to countries below.
71. This is in part because externality effects imply that compliance costs are likely to be high, and in part because there is an entrenched competitive advantage based on current patterns of energy use.
72. Things might be more promising if one considers the sources of carbon dioxide, namely the fossil fuels themselves. For most individuals have to buy their fuel from others; and most countries have to import much of their fuel from elsewhere. (But note that: [a] some countries do have significant fossil fuels of their own, e.g., China's coal reserves; [b] monitoring and enforcing limits on oil production, although one of the easier fuels to monitor, has proved difficult in the past, e.g., for OPEC, and for those imposing sanctions on Iraq; and [c] the emissions produced by any given unit of, say, oil vary considerably depending on use, in ways which make calculations of overall emissions levels difficult, even when the agents involved are compliant.)
73. Note that it would be possible to hold that countries confront a battle of the sexes, even if individuals confront a prisoner's dilemma. There are two reasons. First, the number of actors is very different, making it more plausible in the individual case that decisions made by one party do not directly affect decisions made by the others. Second, on the one hand, a many-person collective action problem often has the character of a prisoner's dilemma as far as a chooser is concerned if: (a) it involves an incremental good with indiscernible contributions; or (b) a step good, and either the threshold is indiscernible or it is not particularly proximate in terms of my choice (i.e., if I do not perceive the crossing of the threshold as a close thing, then what happens is that the effect of my contribution becomes less and less discernible). But, on the other hand, it has the character of a battle of the sexes for the individual if: (c) the good is incremental and contributions are discernible; or (d) there is a discernibly close threshold. Arguably, the intragenerational problem facing individuals seems best characterized by either (a) or (b): (b) with remoteness seems to be the way most people see it; or else (a) with fatalistic attitude. Hence, they are more likely to face a prisoner's dilemma. But one might argue that (c) or (d) is more likely for countries, since they are in a better position to gather information, make agreements, and guarantee certain levels of reduction. Hence, countries might face a battle of the sexes. (For this method of classification, I rely on Waldron, who relies on Hampton.)
74. Hampton says that many actual problems are mislabeled as prisoner's dilemmas when they really have this structure. See Hampton, "Free-Riding. "
75. Waldron characterizes the global warming problem as follows in "Who Is to Stop Polluting," pp. 34-35: (a) There are more than two players. Call the number of players N. (b) There is a number M (such that M < N), which is the minimum number of players whose cooperation is necessary if some situation, which is bad for all, is to be avoided. (c) If M players cooperate, all N players benefit. (d) Each player prefers the situation in which M players cooperate but he is not one of them to the situation in which he is one of the M cooperators. In other words, cooperation is costly. (e) The greater the number of cooperators, the smaller the cost to each of cooperating. Thus each, if he is a cooperator, prefers that the number of cooperators be as large as possible. (f) If any cooperate, and the number of cooperators is less than M, then the cooperators suffer the cost and enjoy none of the benefits of cooperation. Each would prefer not to cooperate than to be in this situation. (g) If the number of others who are wiling to cooperate is just short of M, then a given party prefers to cooperate, since he is better off enjoying the benefits of cooperation and paying his share of the cost than he is in the situation where not enough people cooperate. So, I have picked out Waldron's (b) and (g).
76. See Hampton, 1987. The basic structure of the Battle of the Sexes can be gleaned from the (unfortunately sexist) story from which it gets its name. A couple are deciding whether to go out on a date. The man would most prefer to go to see a game of baseball; the woman would most prefer a trip to the theater. But both prefer to go on the date rather than to go to their own favorite event (or stay at home) alone. This yields the following preference structure: Battle of the Sexes Woman Baseball Theater Man Baseball 1, 2 3, 3 Theater 4, 4 2, 1 In this situation, there is no natural equilibrium position, but the two cooperative solutions are better than either noncooperative solution. Hence, both players are motivated to compromise because both want to avoid the noncooperative outcome. (Note: the phrase 'many-person battle of the sexes' is unfortunately ambiguous between a situation in which all prefer to cooperate, and one where all prefer that some cooperate. Hampton intends the latter.)
77. For example, it preserves the insight that climate change involves some form of collective action problem involving a strong incentive to try to free ride (in this case, by getting others to form the subgroup). Furthermore, it appears to be supported by some aspects of recent real world events. Even in the face of the decision by the United States - the world's single largest emitter - to refuse to support the Kyoto agreement, the other countries of the world have made an agreement that involves significant reductions in projected emissions for the other large emitters (prominently, the European Union and Japan). This suggests both the Partial and Minimal Cooperation claims.
78. This is mentioned by both Mabey et al. and Waldron, and seems to support the Partial Cooperation claim.
79. In particular, a battle of the sexes can be resolved if (a) a particular outcome is salient to both parties as the likely cooperative resolution (and so can act as a rallying point), and (b) for the party who must give up his most favored outcome to secure the salient one, the expected utility of conceding to the salient outcome is greater than that of holding out and so risking a noncooperative outcome.
80. Again, this initially appears to be supported by recent events.
81. The basic battle of the sexes analysis ignores some (further) important strategic factors that emerge once only some countries comply, namely the competitive advantages internal to not making cuts. (For example, one's energy costs are cheaper than one's competitors' not only because they are spending money cutting emissions that will be passed on to consumers in higher prices, but also because these efforts will lower the price of fossil fuels on the world markets by reducing demand for them and encourage emissions-intensive industries to migrate to countries with no restrictions.) And it is possible that they make at least some of the attempt to reduce total emissions self-defeating. (Interestingly, Mabey et al. consider the current scenario unstable, for they believe that defection the United States will make energy-intensive industries leave the cooperating countries in such numbers that the benefits of cooperation for those countries would be outweighed by their costs. See Mabey et al., Arguing, pp. 266, 299, 410.)
82. 2 is not the only greenhouse gas whose emissions are useful to humans; it is merely the one presently most important. (Methane is also very important; bringing the slightly comical problem of bovine flatulence to global prominence.) So, in the end, an even more comprehensive agreement is needed, as Kyoto envisages.
83. Very roughly, for a world population of 6 billion people, this would amount to 123 billion tons of carbon dioxide annually (based on 20.5 tons per capita emissions for the United States, the figure for 1995). This rises to 184.5 billion tons for a world population of 9 billion, which is projected by the U.S. Census Bureau for mid-century. Total projected emissions from energy consumption for 1991 was a mere 26.4 billion tons. (Hence, continuation at 1991 levels would allow a per capita average for emissions of 4.4 tons, which is only 20 percent of the U.S. figure.) Hence, China alone (with a population of 1.2 billion in 1995, rising to 1.5 billion in 2025) could break the 1991 total, even if (as would never happen) other countries emitted nothing. (Slightly) more realistically, and simplifying considerably, even if all other countries cut back 20 percent from their levels in the early nineties - a huge reduction over projected "business-as-usual" growth - (to a total of 21.1 billion tons), a bloc of countries with very low current emissions and a combined population of over 250 million (i.e., 4 percent of the world's population) could conceivably break the 1991 total if they emitted at current U.S. levels. As, of course, would the United States alone if it were the defector. (Figures from the World Resources Institute, as cited by the UNEP Climate Change Kit, http://www.unfccc.int/resource/iuckit/index.html.)
84. This is especially so if the marginal costs of reduction get higher and higher, which they do, so that the costs to a cooperating group goes up the more other countries pollute. This effect would be exacerbated by a reduction in the price of fossil fuels brought about by the withdrawal of demand by the core group.
85. And one might not be delaying it very much. Some say that the current agreement between Europe and Japan will only slow the growth in atmospheric carbon dioxide by six years. (This, of course, ignores the fact that the current agreement only covers emissions from 2008 to 2012, and envisions new targets for future years.)
86. 2 rich ways of life. This would imply that partial cooperation is false after all. Waldron's (e) also suggests that N-M will be small; (e) states that the greater the number of cooperators, the smaller the cost to each of cooperating. Thus each prefers that, if he is a cooperator, the number of cooperators be as large as possible. Hence, each cooperator has an incentive to use any other means at his disposal to put pressure on other countries outside the subgroup to join. Since the cooperation of the large and potentially economically powerful nations is required for success (given the dynamic problem), it will be small and economically not-so-powerful nations who fall into N-M, but these are the most susceptible to external pressure from these nations. Hence, it is to be expected that M will be equal, or very close, to N.
87. It is also worth noting that the more successful the subgroup is to begin with, the greater incentives to the noncooperators to do this, as the better the quality of the commons they can exploit. Furthermore, to maintain the commons, the M are under progressive pressure to do more and more, so that the costs on them in a dynamic context increase dramatically.
88. The theoretical difficulty here may be in treating total abatement as a step, rather than incremental, good. If abatement at some percentage of global 1990 levels really represented a threshold that benefited all, then one might argue that even noncooperators would have an incentive not to disrupt it. But this argument would be a mistake, for two reasons. First, the influence of emissions is, as far as anyone knows, or at least as far as it is treated in the models of the problem, incremental, not a matter of threshold. Hence, there is a threat at the margin. Second, and even more importantly, since "disruption" here simply involves continuing to pollute on a business-as-usual basis (i.e., to the extent that it is a benefit irrespective of concerns about climate), this "solution" would actually turn noncooperators into cooperators. For bearing some of the costs of abatement here simply means not polluting on a business-as-usual basis.
89. Notice the 'may' here. Internal solutions require the identification of a salient solution. But in the case of global warming, this is undermined by the complex nature of the problem. In particular, the identification of a relevant subgroup is undermined by uncertainty about the distribution of costs and by the range of potential contributors.
90. Note that if the intergenerational problem is to be solved, the first generation is already making an absolute sacrifice in terms of self-interest. This makes things difficult in dealing with noncooperators. Suppose they seem quite happy to pollute and not cooperate. Am I supposed to offer them further incentives to come back into the fold? But then I am giving up both my potential gains from polluting (to the future generations), and some of the further gains from cooperation (to the reluctant cooperators). This is a lot to ask. Just overpolluting myself will look very tempting.
91. The problem is that noncompliance, even global noncompliance, is actually a benefit to the present generation so the incentives to enforce are not high.
92. The competitive pressures argument does not work in all contexts, but it does seem operative here. For some doubts about its general application, see Daniel Hausman and Michael McPherson, Economic Analysis and Moral Philosophy (Cambridge: Cambridge University Press, 1996), chap. 4.
93. In addition, note that the problem of overpollution would remain even in the absence of population growth, since energy consumption per capita is on an upward spiral.
94. Furthermore, it is probably a politically necessary prerequisite to preventing the developing countries from following a Western path.