Paul R. Ehrlich & Anne H. Ehrlich, The Population Explosion, 1990.
Population, Growthism, and National Security
For a long time, population growth and economic growth were uniformly considered good. More people in the tribe, city, state, or nation meant more security. More people allowed the divisions of labor and economies of scale by which modern economies advance. Growth in those economies has raised the standard of living of a significant minority of human beings to heights unimagined by anyone before this century.
The tandem growth of populations and standards of living in the West over the last few centuries has led people to believe that population growth would always be an essential stimulant to economic growth. The idea traces back at least to Henry George, who at the end of the last century wrote:
. . . a greater number of people can collectively be better provided for than a smaller . . . the new mouths which an increasing population calls into existence require no more food than the old ones, while the hands they bring with them can in the natural order of things produce more . . . I assert that in a
state of equality the natural increase of population would constantly tend to make every individual richer instead of poorer.l
At the extreme, this idea resulted in an announcement by economist Colin Clark in 1969 that India would within a decade be the most powerful country in the world because of its growing population!2
The vast majority of economists no longer believe that population growth inevitably leads to prosperity, although many still think it is necessary. As Kenneth Boulding commented, "Anyone who believes exponential growth can go on forever in a finite world is either a madman or an econornist."3 Let's take a look at some of the arguments for perpetual growth raised by madmen and economists.
One major "economic" argument that is made for keeping the American population growing is that if we don't our population will grow older, and that will cause major economic and social problems.4 The first part of the statement is undeniable. Whenever a growing population reduces its birthrate and gradually stops expanding, the age composition of that population shifts toward the older age classes. In other words, there will be proportionately fewer young people and more old people. This is simple arithmetic; there is nothing whatever that can be done about it. We are told that this disastrous change should be avoided at all costs. It will lessen innovation, send baby-food manufacturers to the poorhouse, and, above all, burden working people with an army of unproductive oldsters to take care of -- letting ourselves in for a perpetual "Medicare crisis."
None of these arguments is particularly cogent. First of all, unless birthrates drop precipitously, there will be plenty of time for various parts of the social and industrial system to adjust to the changing age composition. Second, although there will be proportionately more old people who need care, there also will be proportionately fewer children. Higher costs in Social Security will be largely balanced by reduced costs for the care and especially the education of children. The ratio of productive to dependent people in the population will not change much.5
Furthermore, while it is unlikely that in the future children will need less care, it is likely that in the future old people will need less care. The health of the American population as a whole is improving, and there is a growing recognition that there is no reason whatsoever to remove people arbitrarily from the economic system at the age of sixty-five. People who remain active live longer and remain healthier and don't need to be supported by younger people. (This does not mean that we'll be able to avoid some difficult social choices, as medical science continues creating ever more expensive life-prolonging treatments.)
As former Deputy Assistant Secretary of State for Environment and Population Lindsey Grant has pointed out, those worrying about too few workers to support too many old people "may be worrying about precisely the wrong problem. Now and in the foreseeable future, the problem seems to be, not a shortage of labor, but rather a redundancy of labor of the wrong types and in the wrong places."6
Recently capital has been moving around the world in search of the cheapest available labor, and population growth has ensured that there is plenty of that. The huge size and resource consumption of the world population today also necessitate increasing trade between nations and regions. The day of the resource-self-sufficient nation is over. But one result of the increasing economic interdependency of nations is a rising mobility of capital. The easy transfer of capital between nations could, under a policy of maximally free trade, lead to the pauperization of America, since the wealth of our nation has been partly based on the ability of workers to make a decent wage.7 As economist Herman Daly noted, "The equilibrium wage under free trade will be the third world level."8
A bonus of the U.S. population's changing age structure is that people in the age class that provides us with most of our criminals, 16-30, will be proportionately fewer in our population. Considering the enormous social and economic costs of criminal activities and of maintaining the courts and the penal system, those savings alone might more than offset any additional expenses of taking care of older people.
The innovation issue is more difficult to deal with. In some academic disciplines, such as mathematics, the most  innovative steps are made by young people. In science as a whole, innovation may be more concentrated in the middle years, when a balance between new thinking and experience is of value. But whatever the loss in innovation, if any, in a somewhat older population, it may be more than made up for by an increase in experience. There are, of course, additional ways to assure that levels of innovation do not drop. One is to start taking advantage of the potential for innovation in young minds when they are found in women, members of minority groups, or the desperately poor.9 We should be doing that regardless of society's demographic status. Others include changing both the educational system and society as a whole in ways that encourage innovation. There is no evidence that brute numbers of young minds are the wellsprings of innovation. Otherwise, there would have been no Golden Age for Athens, and China and India would be the world leaders in innovation.
The absurdity of the "don't stop growing because we'll grow old" view is that soon or later America (like every other nation) must stop growing. So the "problems" of an older population will have to be faced sooner or later. By pushing that moment off to "later," we are simply condemning our children or grandchildren to dealing with problems of age composition in a world that is much more overcrowded and much more resource-depleted and has a much more malign environment. By not working to stop growth now, we may be mortgaging any chance at all for the next few generations to lead decent lives.
With these exceptions, direct connections between population growth and economic issues are rarely heard. But policy-makers cling to the dogma that economic growth itself is essential to the health of society, and that such growth can cure population problems -- on one hand, by providing materially for an indefinitely large population, and, on the other, by leading to a halt in population growth via a demographic transition, a topic to which we will return.
It has long been clear to ecologists that the extreme growth orientation of mainstream economics is a major reason that politicians, businessmen, and others advised by economists,
as well as the public at large, fail to recognize the increasing seriousness of the population crisis in particular, and the deepening predicament of Homo sapiens in general. Most people do not recognize that, at least in rich nations, economic growth is the disease, not the cure. They are infected with a blind faith in the efficacy of growth to solve all problems and lead them to the promised land; they have put their faith in what may be terminal growthism. They do not recognize that "perpetual growth is the creed of the cancer cell,"10 that growth must cease at maturity.
Some farsighted economists have attempted to swim against the tide of dogma in this area; Herman Daly is the outstanding contemporary example.11 But Daly's cogent analyses have been largely ignored by the economic establishment, although they are attracting the attention of some bright young economists.12 One group at World Resources Institute has pioneered in developing a new method for measuring a nation's economic performance that includes accounting for the depletion of natural resources such as wildlife, forests, fisheries, groundwater, and soils, as well as minerals, in national-income reports.13 This sort of accounting, if widely adopted, would provide a far more accurate picture of economic progress and the outlook for all nations. Much of what today is considered "production" causes ecological destruction, which never appears in conventional national balance sheets. The result is a false impression of wealth.
These ideas are still foreign to most economists, however. The failure of conventional economics to contribute to a resolution of the human predicament is understandable from a cursory examination of what economists are taught. All one need do is look at the circular-flow diagram that "explains" the generation of gross national product in any standard economics text. There are no inputs into the circular flow; it is simply a diagram of a perpetual-motion machine, an impossibility except in the minds of economists. Economics texts, of course, give no coverage at all to what is now the central question of economics: How big can the economic system be before it irretrievably damages the ecological systems that support it?14
The majority of economists have never been taught that ecosystems provide humanity with an absolutely indispensable 
array of services, services that are "free," but would, of course, be infinitely costly to replace. They are ignorant of the role that natural ecosystems play in regulating trace gases in the atmosphere, providing fresh water, generating soils, and preventing floods and droughts.
Since they are unaware of the stress that natural systems are now under, most economists believe that the scale of economic activity can be increased indefinitely (or at least so far into the future that limits to growth need be of no concern today). Many share with British economist Wilfred Beckerman the notions that economic growth has gone on "since the time of Pericles" and that there is "no reason to suppose that it cannot continue for another 2500 years."15
Both ideas are straightforward nonsense, as a few simple calculations by social scientist Jack Parsons showed.16 He calculated what the income of the average English household would have been at the time of Pericles (490-424 B.C.) if growth had gone on since that time at the rate of one percent a year.17 Note that that rate would be considered disastrously low by today's typical economist. But even at that conservative figure, the English family (if there had been "English families" in those days!) at the beginning would have been poor indeed. It would have had the buying power for an entire year, in 1970 money, of less than a millionth of a penny.
In fact, the state of the economy over most of the sweep of human history was, by the standards of economists today, stagnation.18 As one might expect from this, Beckerman's prediction about the future turns out, if anything, to be sillier than his misrepresentation of the past. Parsons applied the same conservative one percent annual growth rate to the English economy into the future from 1970. At one percent per year, the per-capita gross national product (GNP)19 would double about once in a lifetime (seventy years). At that rate, it would take only about fifteen hundred years for the hourly wage in Britain to hit a million dollars (that's not inflation, that's in 1970 dollars). In A.D. 4470, or 2500 years in the future from 1970, an English child's weekly allowance (about one half of one percent of the weekly per-capita GNP) would have the purchasing power of about ten billion 1970 dollars.
The absurdity of the idea of perpetual economic growth is
 highlighted by Parsons' notion of the "millionaire barrier." After less than seven hundred years of one percent growth, the average person in England (or the United States) would have an income of over a million 1970 dollars annually. Who then would do the work to produce what all the millionaires would consume, and who would clean up after them? Presumably, economists would expect the populations of the poor nations to avoid growth and dedicate themselves to the task of supporting and serving the idle rich nations whose economies would miraculously keep growing!
One important relationship today between economic growthism and population growth is that the growthism keeps economists from becoming influential advocates of population control. As long as economists and those who listen to them believe there are no limits to growth, the pressing need for population control will not be obvious to them. Their failure to recognize those limits is partly rooted in two related axioms of mainstream economics: that there is an infinite number of resources, and that a satisfactory substitute can be found for every resource.
DESTROYING THE WORLD FOR PROFIT
Biologists unfamiliar with economic theory are often shocked when they discover an industry that appears to be deliberately destroying its resource base. The problem first came to our attention when it became clear that the whaling industry was knowingly harvesting whales at a rate that would lead to their extinction. Until then, it had not dawned on us that industries dealing with biological resources were not necessarily concerned with achieving long-term maximum sustainable yields from them, but were concerned primarily with maximizing the current return on their capital. If exterminating the resource (pumping aquifers dry, wiping out the whales, clear-cutting tropical rain forests, exhausting the soils on factory farms) brought the maximum return, then the resource would be destroyed.
This behavior is based in part on the first axiom of mainstream economics:20 since an infinite array of resources is  believed to exist, once one resource has been utterly destroyed there will always be another that can profitably be exploited to extinction, then another, and another, and another.21 People a decade hence will be dealing with an entirely new set of resources!
These attitudes have led to many unwise decisions for the long term, such as ignoring the need for worldwide conservation of topsoil or petroleum, rapidly depleting aquifers, and building large dams and then deforesting the watersheds above them.
But even if the first axiom were true, and there were an infinity of resources to plunder, that would not necessarily solve our problems. There could (in an unreal world) be an infinity of resources, but each having dramatically different properties. Then, even though the opportunities to profit from their exhaustion might be infinite, some resources would be irreplaceable in terms of the function they can serve in the human economy (fresh water is a good example). Depletion of one key resource in the spectrum therefore could limit the scale of the human enterprise.
Since such a proposition would cast doubt on the "grow forever" central dogma, economists have resorted to assuming the problem away through the second "infinite substitutability" axiom. They justify it by a total misinterpretation of the fundamental physical, chemical, and biological rules that govern the real world.
THE LIMITS TO SUBSTITUTION
Economists Harold Barnett and Chandler Morse most clearly expressed the second axiom:
Advances in fundamental science have made it possible to take advantage of the uniformity of energy/matter -- a uniformity that makes it feasible without preassignable limit, to escape the quantitative constraints imposed by the character of the earth's crust. . . . Nature imposes particular scarcities, not an inescapable general scarcity. Man is therefore able, and free, to choose among an indefinitely large number of alternatives.
There is no reason to believe that these alternatives will eventually reduce to one that entails increasing cost -- that it must sometime prove impossible to escape diminishing quantitative returns. Science, by making the resource base more homogeneous, erases the restrictions once thought to reside in the lack of homogeneity. In a neo-Ricardian world, it seems, the particular resources with which one starts increasingly become a matter of indifference.22
Of course, Barnett and Morse had the laws of physics exactly backwards -- since it is the lack of homogeneity that makes "resources" possible. If Earth were homogenized, there would be no coal, petroleum, iron ore, etc., just a uniform mixture of the atoms that now constitute the planet.23 Energy and matter are not "uniform" just because, in some circumstances, matter can be converted into energy (and in theory the reverse can take place), any more than a fine goblet and a pile of broken glass are "uniform."
But even ignorance of physics is not sufficient excuse for the faith of economists in infinite substitutability. All that should be needed to destroy that faith is casual observation of the practical difficulties commonly encountered in making substitutions. Nuclear power has not exactly been a roaring success as a substitute for fossil fuels; aluminum wire is, in many applications, a very inferior substitute for copper wire.. Some substitutions, such as plastics for other structural materials, petroleum for coal, and small computers for gigantic machines and even entire libraries, appear to be very successful. Indeed, the success of the computer industry in sharply reducing the materials and energy required in processing information is viewed by some as the ultimate proof that humanity can do anything it sets its collective mind to and improve its environment in the process.24
Unfortunately, there is plenty of evidence that the real opportunities for adequate substitution are limited, and that even quite "successful" substitutions in nonliving resources can have their drawbacks. As a single example, plastic cannot now substitute for metals or other materials in many applications, but disposal of plastics (and the toxic wastes generated in their manufacture) creates extremely serious environmental  problems. In the long run, the plastics industry will suffer from the depletion of (and competition for) petroleum and other fossil fuels from which plastics are made, or of wood, from which they can be made. Plastics are a prime example of a substitution that has pushed the T factor in the I = PAT equation in precisely the wrong direction.
Economists are even less aware, by the way, that there are more severe problems in making substitutions among living resources than among nonliving ones. Dams are not usually a satisfactory substitute for the flood-control services of forest ecosystems when the latter are destroyed, and insecticides are poor substitutes for the pest-control services of natural predators when the predators are killed off.25 And, of course, there are no substitutes for clean air, topsoil, or fresh water.
There are several conclusions to be drawn from the problem of "meta-resource depletion"26 -- that is, the reduction of the total number of Earth's exploitable resources through the extermination of populations and species, the destruction of forests, the poisoning and depletion of aquifers, the erosion of soils, the using up of high-grade ore, and so on. As that capital is used up in an attempt to support continual increases in population and per-capita affluence, industrial civilization will gradually grind to a halt. Indeed, economic growth, as measured by change in real gross national product, has been slowing down in industrialized nations. Japan, which was growing at an average annual rate of 9.4 percent in 1965-73, dropped to 4.1 in 1973-86. In the same period, economic growth in the United States dropped from 3.1 to 2.6, and average growth rates in most European nations, Canada, South Africa, and Australia were cut about in half.27 That, of course, is as it should be. Any more stuff in the world certainly should not go to the likes of us!28
EDUCATION FOR ECONOMISTS AND OTHERS
In our opinion, whether humanity will be able to move toward a population size and an economic system sustainable largely on income will depend in no small degree on economists. The basic biological and physical science of the human dilemma is well enough understood to permit sound recommendations for
 immediate action.29 But almost no work has been done on ways to make the needed conversions in economic systems so that scientific recommendations can be implemented with a minimum of disruption.
The discipline of economics will be a central one as humanity struggles to maintain Earth's habitability. And that is appropriate, for it was an economist, Thomas Malthus, who first recognized the key role played in human affairs by population growth. The seeds of change are there. A few economists have united with biologists to form the International Society of Ecological Economics and publish the journal Ecological Economics.30 And it is already recognized by many economists that graduate education in the discipline focuses too little on important questions of policy and too much on learning to manipulate esoteric mathematical theory based on preposterous assumptions.31
Somehow the new interdiscipline of ecological economics seems a natural union, as the common origin of the words "ecology" and "economics" (referring to nature's housekeeping and society's housekeeping) implies. Today it consists of a group of farsighted economists (considered a fringe group by the rest of the discipline) and increasing numbers of ecologists who are becoming aware of the central role economics must play in solving the human predicament. If we are to escape our current predicament, it should become a major area of specialized education, and replace neoclassical economics as the central focus of economics departments.32
Those being trained in ecological economics would first be given the baseline understanding that society's first priority must be to keep nature's house in order. They would learn that' the key to doing this is to reduce the number of people to a quanti|y that can be properly sheltered without destroying the house. Considerable instruction on the basics of how the physical-biological world works must be included in the training of all economists. Otherwise they will continue to whisper the wrong messages into the ears of politicians and businessmen. The latter, in turn, will continue to see growth of the global economy as the cure rather than the disease, and will remain unconcerned about the population explosion.
Of course, resistance to those fallacious messages could be much enhanced if material on the human predicament were woven into basic teaching in elementary and high school,33 and if every college student in the nation were required to take at least one course that gave a basic overview of the "state of the planet." At Stanford University, there has been considerable uproar over the content of a required "Western Civilization" course. But most students (and most faculty) remain ignorant of the size and growth patterns of the human population, what is involved in producing food, how ecosystems provide essential services to society, the comparative deployment of U.S. and Soviet nuclear forces, how people's perceptual systems give them a biased and inadequate view of the modern world, the basic theory of evolution, and the laws of thermodynamics. All these are more important to the average citizen than what Plato or Richard Wright wrote or who was gathered at the Congress of Vienna (not that well-educated people shouldn't know those things also!). The complacency with which our education system at all levels accepts the production of citizens hopelessly unequipped to understand the population explosion and many other aspects of the modern world is a national disgrace.
Can economists unite with ecologists, reform their discipline, and help pull humanity through the crisis decades ahead? We hope so. You will know there is a chance when the President's Council of Economic Advisors recommends that it be subsumed in a new "Council of Demographic, Ecological, and Economic Advisors," when a central task of economics is seen to be devising an economic system with the proper scale and attributes to permit it to function permanently within environmental constraints, when economic growth is always discussed in a context of counterbalancing shrinkage and redistribution, and when GNP is replaced by some measure that takes into account resource depletion and ecosystem deterioration as minuses. When all economists realize that perpetual growth is both impossible and undesirable, economics as a profession will have become a force for survival rather than for destruction, as it all too often is now.
DO WE NEED CANNON FODDER?
Arguments in favor of population growth that are unconnected to issues of economic growth are sometimes made. One of the most imbecilic is that the safety of the nation demands large numbers of people to keep up military strength.34 The basic idea appears to be that the more cannon fodder a nation has, the more security it has. By those standards, of course, neither China nor India has a worry in the world militarily. They should be the superpowers, and poor Israel with only 3 million people should be terrified by the threat posed by some 90 million enemies in nearby nations. By these lights, Russia (population then 170 million) should have handily defeated Germany (population 65 million) in the First World War,35 and Japan (population 70 million) would never have had any success in taking on China (population 500 million) and then simultaneously the United States (population 140 million) in the Second World War.36
In fact, the notion that population size by itself provides military power is utter nonsense. In modern times victory has rarely gone to the possessor of the larger battalions for that reason alone. Leadership, morale, technological capabilities, and, in recent history, industrial strength above all have determined the eventual winners. Within wide bounds, population size has been irrelevant. In two world wars, a vastly outnumbered Germany very nearly defeated its enemies on the basis of industrial prowess, superior military organization and tactics, internal lines of communication, and the best infantry in the world. Israel has kept its larger neighbors at bay with a better-educated population, better-trained troops, a superior grasp of technology, and the benefit of drawing upon the industrial and technological resources of the United States. Israel's enemies have had to make do largely with the inferior and limited industrial/technological support of the Soviet Union. Similarly, the Vietnamese beat first the French and then the Americans even though they were outnumbered in the latter instance by more than four to one.37
ENVIRONMENTAL THREATS TO NATIONAL SECURITY
Most of the world's other rich nations realize that there is now an unparalleled nonmilitary threat to their security. It has been created by rapid depletion of Earth's nonrenewable resources, deterioration of the global environment, and the widening of the economic gap between rich nations of the industrialized North and poor nations of the South -- all contributed to mightily by exploding human populations. That threat not only portends a continual deterioration of living standards virtually everywhere in time of peace, but also contributes to conflict between nations38 and thus increases the chances of nuclear war.
An end to civilization caused by overpopulation and environmental collapse would amount to a gigantic "tragedy of the commons" -- to use the phrase made famous by Garrett Hardin.39 Individuals (or nations) acting independently for their short-term gain create situations that, in the long term, destroy common resources ("the commons").40 As Hardin wrote, "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. Freedom in a commons brings ruin to all." His reference is to overgrazing of a village's common pasture; civilization's ruin will stem from treatment of the global ecosystem as a "commons" that can be exploited by every nation without thought for their common security.
Perhaps no feature of Earth is more a commons than the atmosphere. The atmosphere connects all nations and people, past and present, and it interacts intimately with oceans and land, including plants, animals, microorganisms, and soils, as a major component of ecosystems. Disruption of atmospheric ecosystem services can have grave international repercussions. For instance, the climate of the Soviet Union's wheat belt might deteriorate as a result of greenhouse warming. The United States might suffer similar agricultural problems and have no grain to sell abroad. If the Soviets were in need of imported grain, tension between the two nations could rise, and those tensions might be aggravated by agricultural  problems in other regions, which could no longer obtain food imports. We have become so interdependent that each nation's security increasingly depends on the security of others.
Altered rainfall patterns, which are virtually certain to accompany a global atmospheric warming, could also exacerbate tensions over increasingly scarce water supplies in places as disparate as the Middle East and along the U.S.-Mexico border. Egypt, whose population is projected to increase from 55 million in 1989 to 71 million in 2000 and 103 million in 2020, is already tottering on the brink of chaos. A significant reduction in the Nile's flow would push it over the edge. If rainfall became sparser in the Middle East or demand for water increased significantly, an explosive situation would become much worse. The waters of the Jordan, Yarmuk, and Litani rivers have been sources of tension for years, and the 1967 Arab-Israeli war was fought in part over them. It is sobering to consider that Israel, which consumes five times as much water per capita as its neighbors, may have a serious water shortage in the 1990s, even without climate change.41 The hard-nosed Israeli stand on the West Bank and Gaza since 1988 may be just a foretaste of what is to come, since Israel is now using about 95 percent of its renewable water supplies.42
International tensions also could be heightened by reduced river flows between Pakistan and India (over the Indus) and India and Bangladesh (the Ganges). Disputes over water have occurred in those regions and in the basins of the Tigris/Euphrates, Amur, Mekong, and Nile rivers, and the Rio de la Plata. The waters of 120 of the world's 200 major river systems are shared by two or more countries.43 With the entire planet overpopulated and serious regional water shortages already widespread, the potential for drought-induced conflict is enormous.
These are not distant problems for Americans. A significant decline in the dependable supply of water available from the Colorado River could lead to further trouble between Mexico and the United States. Such a conflict could be greatly intensified by more Mexicans seeking to enter the United States in order to make a living.44 Agricultural conditions in many regions are deteriorating as productivity declines  because of soil erosion, failing irrigation systems, desertification, or changes in climate. The inevitable result is an increase in the worldwide flow of ecological refugees.
Transnational air-pollution problems also will be affected by global warming, but in ways that are virtually impossible to predict. Forest systems, already stressed by air pollution and acid precipitation, are not likely to respond well to abrupt changes in temperature and rainfall regimes. Indeed, there is evidence that some forests in the northeastern United States are already being degraded by the combined stresses of pollutants and climatic change.45
In the longer term, changes in ocean temperatures, rising sea levels, and changed freshwater flows could affect the dynamics of oceanic fish populations and, temporarily at least, depress productivity. World fishery harvests have been barely keeping up with population growth for the last two decades, and are now thought to be approaching, if not beyond, maximum sustainable yields. Per-capita declines seem to be in store in the near future (drops over short periods have already occurred), even without changes in oceanic environments that are (in terms of evolutionary time) very rapid. Shots have already been fired over fishing rights; that may be only a hint of things to come unless cooperative and sustainable management of the fisheries commons can be achieved.
Other large-scale problems with the atmospheric commons facing humanity include increased ultraviolet-B radiation as a consequence of stratospheric ozone depletion, acid deposition, and other forms of air pollution. But serious though these are, climate change, with its clear population connection, has the greatest potential for contributing to international conflict and for diminishing the economic security of all nations.
1. H. George, 1902, Progress and Poverty, 4th ed. (Doubleday, Page, New York, 1902), p. 141. The book was originally published two decades earlier; George was responding to a Malthusian statement by John Stuart Mill.
2. Quoted in P. Ehrlich, A. Ehrlich, and J. Holdren, Ecoscience: Population, Resources, Environment (Freeman, San Francisco, 1977), p. 807.
3. Quoted by L. Grant, "Too Many Old People or Too Many Americans? Thoughts About the Pension Panic," NPG Forum, July 1988. Boulding is himself an extremely distinguished economist, whose classic article "The Economics of the Coming Spaceship Earth," in H. Jarrett, ed., Environmental Quality in a Growing Economy (Johns Hopkins Press, Baltimore, 1966), should be read by every economics student right after completing a course in ecology.
4. A recent source for this and many of the other specious arguments for population growth found in this chapter is B. Wattenberg, The Birth Dearth (Pharos Books, New York, 1987). See also J. Rauch, "Kids as Capital," Atlantic Monthly, August 1989.
5. Demographers speak of the "dependency ratio" -- the proportion of people in the productive age classes, defined as 15-64 years of age. In the U.S., that ratio has fluctuated between 61 and 66 percent between 1940 and 1985, with no perceptible impact on the economy. If fertility doesn't change much in the future, it will climb to about 69 percent by 2010 and then decline to 63 percent by 2025. The source of these figures is L. Grant, "Too Many Old People or Too Many Americans?"
6. L. Grant, op. cit.
7. Early followers of Adam Smith, economists David Ricardo and John Stuart Mill developed the theory of comparative advantage and showed the benefits of free trade under the assumption that (as Ricardo put it) people's disinclination to leave the country of their birth and subject themselves to the laws of strangers would "check the emigration of capital." These pioneers never envisioned that capital would become mobile. They could not imagine that an American television manufacturer might set up shop in Taiwan to take advantage of lower labor costs, or that a Taiwanese manufacturer might move his capital and technological expertise to Bangladesh for the same reason. They did not know a world of multinational corporations in which transfers internal to the firm could be international. Modern economists so love the old logical argument for comparative advantage that they have ignored that its foundation, capital immobility, has crumbled, and that, as a result, absolute advantage will increasingly rule.
This issue is discussed in depth in H. Daly and J. Cobb, Jr., For the Common Good: Redirecting the Economy Toward Community, the
Environment, and a Sustainable Future (Beacon Press, Boston 1990) This book is a must for all those interested in the state of Earth's economic system -- it doesn't oppose international trade, but presses for balanced trade between national communities as opposed to free trade among individuals across national boundaries.
8. "Steady-State Versus Growth Economics: Issues for the Next Century," paper given at Hoover Institution Conference on Population, Resources and Environment, Stanford University, Feb. 1-3, 1989.
9. Although this discussion is focused on the U.S., we must point out that there is much more wastage of minds in poor countries, where millions of children are retarded by malnutrition and have little or no opportunity for education.
10. As Edward Abbey used to say. He is sadly missed; his last book, The Fool's Progress (Henry Holt, New York, 1988), is a novel that touches cogently on many of the issues discussed in this book.
11. Daly's work has been built on foundations laid by John Stuart Mill, Kenneth Boulding, and Nicholas Georgescu-Roegen. See, for example, H. Daly, Steady State Economics: The Economics of Biophysical Equilibrium and Moral Growth (Freeman, San Francisco, 1977); and Daly and Cobb, Jr., For the Common Good. Daly's brilliant writings are the best introduction to ecological economics.
12. We have been cheered by the writings of John Gowdy at Rensselaer Polytechnic and Joseph Vogel at the University of Southern Mississippi. Sadly, the economics departments at the most prestigious universities tend to be both the most isolated from reality and the most dogmatic. Resource economists, who understand many of the issues discussed here, have had little impact on the profession as a whole.
13. R. Repetto, W. Magrath, M. Wells, C. Beer, and F. Rossini, Wasting Assets: Natural Resources in the National Income Accounts (World Resources Institute, Washington, D.C., 1989).
14. More technically, the central economic question ought to be: How can the costs to society of the impacts of the different economic agents on the functioning of ecosystems be internalized in such a way that those agents will respond to those "true" costs, which are now externalities? If that could be properly done, the scale of the economic system would presumably adjust itself so as to leave ecosystem services largely unimpaired.
15. W. Beckerman, "Economists, Scientists, and Environmental Catastrophe," Inaugural lecture, University College, London (unpublished).
16. J. Parsons, Population Fallacies (Elek/Pemberton, London, 1977). This excellent book contains much material pertinent to this chapter.
17. This, of course, refers to economic growth per capita.
18. For a more detailed discussion see Ehrlich, Ehrlich, and Holdren, Ecoscience. Over the last couple of millennia there in fact has been a pattern of alternating economic growth and shrinkage -- not constant growth. For example, the purchasing power of builders' wages in the south of England was higher in 1500 than it was in 1850.
9. A nation's GNP is its total annual output of goods and services. It is a convenient economic indicator, but per-capita GNP unfortunately is often confused with an index of the quality of life (QOL). To claim that 
per-capita GNP does measure quality of life (as some would) involves making some extremely culturebound value judgments and concluding that the average American has a life twice as high in quality as an average New Zealander and 10 times as high as an average Costa Rican. It requires one to believe that a Los Angeleno is perhaps 100 times better off than one of America's Founding Fathers or a Bushman or an Eskimo before contact with European culture. Only someone who equates quality of life primarily with quantity of gadgets could hold such a view.
20. It is also based on the "common-pool" problem of economics, discussed later under the rubric "the tragedy of the commons."
21. Technically, this belief allows economists to think we can live in a world of high discount rates forever.
22. H. Barnett and C. Morse, Scarcity and Growth: The Economics of National Resource Availability (Johns Hopkins Univ. Press, Baltimore/ London, 1963), p. 11.
23. The ultimate homogeneity would even destroy the distinctions between the atoms.
24. The largely unmeasured ultimate social and environmental costs of such "successful" substitutions may one day give us an entirely different perspective -- and greatly dampen expectations of reducing the environmental damage done by growing populations by working on the T factor in the I = PAT equation. Is paper actually saved by computers? You certainly couldn't prove it from the flow from high-speed printers in our vicinity! And what are the costs in loss of privacy when everyone's financial transactions are in computers? Computers may make the storing of library materials more convenient, but what do they do to the cost and convenience of using them? How do we evaluate the military uses of computers, especially if they begin to take control of military decision-making (as they would if the U.S. or the Soviet Union went into a "launch-on-warning" strategic posture)? We are heavy users of computers ourselves, but it is nonetheless not certain that their benefits outweigh their costs; the issue is complex.
25. P. Ehrlich and H. Mooney, "Extinction, Substitution, and Ecosystem Services," BioScience, vol. 33, pp. 248-54 (1983).
26. P. Ehrlich, "The Limits to Substitution: Meta-Resource Depletion and a New Economic-Ecological Paradigm," Ecological Economics, vol. 1, pp. 9-16 (1989).
27. WRI and IIED, World Resources 1988-89 (Basic Books, New York, 1988).
28. An exception here is South Africa, where the disenfranchised majority is badly in need of economic growth.
29. That, of course, doesn't mean that no further research is required; more information is badly needed so that recommendations can be fine-tuned and our progress (or lack of it) monitored. It is already clear, for instance, that the flux of greenhouse gases into the atmosphere should be reduced as rapidly as possible, but additional knowledge will be required to enable us to make sound predictions of the pace and direction of regional climate change, and to make judgments on the most effective measures to take to mitigate them.
30. First issue published January 1989 by Elsevier Science Publishers P.O. Box 330, 1000 AH Amsterdam, The Netherlands.
31. Many graduate students in economics, realizing that advancement in the field requires emphasis on such questionable exercises, conclude "that graduate economics education is succeeding in narrowing students' interests." But a survey by two economists (D. Colander and A. Klamer, "The Making of an Economist," Journal of Economic Perspectives, vol. 1, pp. 95-111 ), from which the quote is taken, of the students' opinions of the importance of reading in other fields to their development as economists did not even list ecology or any other biological science among the fields to be scored by the students. Moreover, the lowest score given was to physics. Only 2 percent of the students considered it very important, 6 percent important, and 27 percent moderately important, whereas 64 percent rated it unimportant. Small wonder the equivalents of perpetual-motion machines remain embedded in economic thought!
32. A major barrier to this, as well as to other interdisciplinary work, is the conservatism and highly bureaucratic structure of universities.
33. Suggestions on how to do this can be found in R. Ornstein and P. Ehrlich, New World/New Mind (Doubleday, New York, 1989). We do not suggest special courses at these levels, since most school systems are already failing to turn out students adequately prepared in English, mathematics, geography, history, science, or even the basics of how our government works. There is little point in teaching about the loss of biodiversity in the Amazon basin if the students don't know where (or what) the Amazon is.
34. B. Wattenberg, The Birth Dearth.
35. Germany forced Russia to sue for peace even though the Germans were also fighting the French, the British, the Italians, and the Americans (combined populations about 220 million, not counting colonies) on the western front.
36. The Japanese conquered much of China, destroyed British and Dutch power in the Pacific, and (briefly) gave the United States and Australia a run for their money, in spite of the enormous population differentials in favor of the Allies. We didn't add in the British, Dutch, and Australian populations, since many of their resources had already been expended against Germany and Italy. For a thorough examination of the basic elements of national strength, see P. Kennedy, The Rise and Fall of the Great Powers (Random House, New York, 1987). For a fine brief look at how Japan managed to be so successful for the first 6 months after Pearl Harbor, and at how Isoruku Yamamoto and others realized that the comparative strengths of the industrial plants of the U.S. and Japan preordained Japan's defeat, see J. Keegan, The Price of Admiralty (Viking, New York, 1988).
37. Numbers also don't count much today in the great East-West confrontation. The Soviet Union outnumbers the U.S. (1990 Soviet population, 292 million; U.S., 251 million). Nonetheless, the Soviet side is weaker by most military standards. NATO nations have greater technological capability than those of the Warsaw Pact. That difference in capability applies to the Soviet forces themselves. Their weapons are less sophisticated, and major units of the Soviet ground forces are composed of minority troops that do not speak Russian. In many Soviet infantry and armored units, the average soldier isn't even trained to read a map. (For an interesting, if controversial, look at the Soviet Army from the inside, see V. Suvorov, Inside the Soviet Army [Macmillan, New York, 1982]. Other important books on this subject are A. Cockburn, The Threat: Inside the Soviet Military Machine [Random House, New York, 1983], and T. Gervasi, The Myth of Soviet Military Supremacy [Harper and Row, New York, 1986]).
Above all, the Russians can't be certain which side their various satellite armies would fight for. Military strength often can be more a question of liie quality of allies than of brute numbers. Our Joint Chiefs of Staff have repeatedly testified that they wouldn't trade our forces for the Soviet forces. Indeed, since it would take only a couple of dozen nuclear weapons to destroy the Soviet Union as a functioning entity (and about the same number for the U.S.), the Israelis alone probably have enough military power to deter any sane Soviet leader from attacking them. (Midair-refueled, nuclear-capable Israeli aircraft could bomb cities in southern Russia, and Israel has reputedly acquired intermediate-range ballistic missiles. There is no reason to think that the Soviets would be willing to trade, say, Odessa and Rostov for the destruction of Israel.)
38. A. Westing, ed., Global Resources and International Conflict (Oxford Univ. Press, New York, 1986).
39. G. Hardin, "The Tragedy of the Commons," Science, vol. 162, pp. 1243-48 (1968).
40. The original commons referred to by Hardin was undivided pasture-land, used communally. It was to everyone's individual advantage to maximize the number of sheep herded on the commons; in aggregate, this led to overgrazing and disaster for all herdsmen.
41. J. Cooley, "The War over Water," Foreign Policy, no. 54, pp. 3—26 (1984).
42. S. Postel, personal communication.
43. N. Myers. "The Environmental Dimensions of Security Issues." Mimeo. Myers has written extensively on these subjects. See also his "Population, Environment, and Conflict," Environmental Conservation, vol. 14, no. 1, pp. 15-22 (1987).
44. P. Ehrlich, D. Bilderback, and A. Ehrlich, The Golden Door: International Migration, Mexico, and the United States (Ballantine, New York, 1979).
45. S. Hamburg and C. Cogbill, "Historical Decline of Red Spruce Populations and Climatic Warming," Nature, vol. 331, pp. 428-30 (1988).