The Garrett Hardin Society

Updated 1 December, 2003

From Shortage to Longage: Forty Years in the Population Vineyards

Originally published in Festschrift in Honor of Dr. Garrett Hardin
Population and Environment: A Journal of Interdisciplinary Studies Volume 12, Number 3, Spring 1991
Copyright 1991 Human Sciences Press, Inc.

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Covariation is a treacherous indicator of causation. When the first Earth Day was celebrated in 1970 there was much talk of population size as an element in the production of pollution and environmental degradation. Unquestionably Paul Ehrlich's The Population Bomb, published two years earlier, was largely responsible for the sudden surge in public perception. In the ensuing twenty years world population increased by 1,600 million people--some 43%-while the American population increased by 50 million, or 25%. Was there, in the celebrations of Earth Week 1990, a corresponding increase in the emphasis on population? Quite the contrary: Population was scarcely mentioned. Should we then conclude that the larger a population grows the less important population size is?

Biologists take the opposite view. Impacts of a population on the environment are of two sorts: the reduction of wanted resources and the addition of unwanted wastes. Both kinds of impacts are proportional to population size. The per capita impact of population can be lessened somewhat by changes in technology and life-styles, but the asymptote of the per capita impact curve is well above zero. The fundamental equation connecting the variables can be expressed in simple words:

Total impact = (per capita impact) x (population size)

In 1798 Malthus thought that the principal impact of population growth was to be found in the creation of a scarcity of food. Unfortunately for his reputation, the progress of science and technology in the nearly two centuries since his celebrated essay was published has actually resulted in an increase in the per capita production of food worldwide. This does not mean that starvation has disappeared: distribution is (and has always been) imperfect.

During the same period, however, the per capita production of pollutants has also increased, as has the degradation of many of the environmental amenities, e.g., uncrowded beaches and pristine wilderness. In his posthumous book, A Sand County Almanac, Aldo Leopold remarked that "One of the penalties of an ecological education is that one lives alone in a world of wounds." Thirteen years later Rachel Carson, in Silent Spring, brought ecological education to Mary R. and John Q. Citizen. Now we all live in a world of wounds. (This is an improvement over ecological ignorance.)

Although definite progress has been made in mitigating some of the adverse effects of population-powered industrialism, new insults to the environment have been uncovered since Leopold and Carson, e.g., acid rain and greenhouse gases. The magnitude of these environmental insults is clearly proportional to the size of the human population (and to other factors too, of course). The cost of mitigation necessarily rises faster than population size, but that does not deter a few compulsively cheerful defenders of pre-ecological economics from asserting that we have nothing to worry about because the human brain is "the ultimate resource," its power being (it is asserted) quite unlimited. We are grateful to Keith Caldwell for the last word in this matter: "Whom the gods would destroy they first make optimists."

Demographers-the specialists officially in charge of population studies-are neither optimists nor pessimists. They see their task as one of counting everything human. Nondemographers sometimes wonder how many of their data will ever see important use. Examine, if you will, any issue of the Demographic Yearbook published by the United Nations: what fraction of the millions of figures recorded therein will ever be of any use to anyone? Surely the fraction must be small, principally because the probable error of the figures is never given because it is unknown. We are lucky if the official population figure for the world is accurate to within 5%that means an uncertainty of plus or minus 265 million! (Such an error is greater than the total U.S. population.)

Or look at the output of the World Fertility Survey, which was carried out during the 1980s. Women's expressed intentions in the matter of family formation were determined by the polling of many nations. The cost of this effort was in excess of $50 million. No doubt the carrying out of this survey reduced unemployment among the young academics who did the work, but no one has been able to point to any substantial intellectual product flowing from all the effort. So why was such a survey carried out?

The discipline of psychiatry offers us a useful insight. Psychoanalysis depends on the free flow of talk from the patient, but analysts are acutely aware that the flow sometimes becomes a flood. When a patient compulsively and repeatedly verbalizes the anxieties of his daily life the analyst concludes that he suffers from logorrhea-diarrhea of the larynx, to translate freely from the Greek. It is the deluge of words (logos), rather than the words themselves, that is psychologically significant. The psychiatrist asks himself, "What is the patient trying not to say? Why does he work so hard to avoid meaningful communication?"

At the present time there is much talk about the importance of bringing more "numeracy" into public education. The goal is indeed a good one; but just as words can be multiplied beyond benefit so also can numbers be gathered and processed too zealously. The pathology of rhetoric we call logorrhea; the pathology of numeracy produces a statistical diarrhea that we can call arithmorrhea.

In the physical sciences theory is built on fundamental data that are constant. The resultant web of theory permits confident predictions of the consequences of altering parameters in the system. By contrast, the data of the behavioral sciences are not constant, and they are poorly integrated into theory. Encouraged perhaps by successes in the physical sciences, demographers have accorded too much confidence to past historical trends, often with ludicrous results. In 1946 demographers at the U.S. Bureau of the Census, scanning the trend of the past few decades, predicted that the population of the United States in the year 1990 would be 165 million. The year 1990 has now arrived and the population is 54% greater than predicted. Rene Dubos was quite right when he said, "Trend is not destiny." Lacking the ability to turn their data into reliable signposts of the future, demographers gather a great many data that are sadly dispensable.

The public has been so well indoctrinated with the ideals of the natural sciences that it supposes that any numbers that can be gathered may be useful some time, some place. Only a few voices questioned whether it was really worth the expenditure of $2.3 billion to carry out the 1990 census of the United States. (It is not generally known that the Netherlands has not taken a census since 1973, nor has the government any present intention of taking another. We note that Holland is not exactly what one would call a backward country. Maybe the Dutch know something we do not.)


At least for the immediate future I think the greatest progress in the study of population will be made not by gathering more statistics but by discovering and making clear a few fundamental concepts. The impact equation given earlier is one such fundamental. This in turn rests on the idea of carrying capacity, the limit to the number of animals a given territory can safely support for an indefinite period of time, without damage to the environment. Unless the limitedness of carrying capacity is admitted there is little point in counting the number of living bodies.

When we come to the human species the concept of carrying capacity must be enlarged to that of the cultural carrying capacity. Human beings are not content to live at the lowest possible level of resource exploitation, though that would maximize the size of the human population. Instead, we prefer to use resources with some extravagance-to introduce light, heat and cooling into our buildings; to manufacture fashionable clothing that does more than merely shield the body from intemperate weather; to build and use automobiles, airplanes, sailing vessels; to finance vacations; to write, print and stockpile books; and so on. The greater the extravagance the higher the material standard of living - the lower must be the cultural carrying capacity of the environment. What standard of material comfort we should regard as proper is a matter for continuing debate.

Every standard implies limits. Thanks to science and technology, material limits have moved upward during the past two centuries. Not surprisingly, this progress has led many scientifically illiterate people to deny the existence of limits entirely. During the 1980s compulsive optimists seized the reins of political and media power, thus contributing to the suppression of the discussion of population during the Earth Week celebrations of 1990. By this time population was, in some quarters, almost a tabooed subject.


Taboo begins its reign of repression with the choice of words. Consider the word "shortage." If a community requires 100 units of energy to live for one year (at a specified standard of living), but is able to secure only 99, it is automatically said that "there is a shortage of energy." Instead of speaking of a shortage of supply we could just as truly say that there is a longage of demand. As we seek solutions to practical problems why do we never use the word "longage"?

To begin with, the word "longage" is not in any dictionary (though I was so tactless as to coin it in 1975). On the other hand, according to the Oxford English Dictionary, "shortage" has been in use since 1868. Though every shortage of supply is equally a longage of demand, commercial agents always focus on shortages. Curing shortages produces profits. Manufacturers, transporters and merchandisers all stand to gain by increasing supplies. Longages are another story. If, in our minds, we translate a shortage of energy into a longage of people-or a longage of demand per person-we then discover that it is not easy to find competent enterprising agents who stand to gain by reducing a longage. For many centuries philosophers, clergymen, and idealists of many sorts have harangued humanity about the importance of reducing demands, curbing extravagance, and living a simpler life; but no Fortune-400 business has been built on reducing demand. So why mention longage at all if there is no profit in it?

When we come to population matters there are good reasons for at least considering the possibility of reducing demand. When population growth is involved we face this paradoxical truth: You can't cure a shortage by increasing the supply. Given the exponential nature of population growth, once the repressive effect of a felt shortage is removed, the multiplication of demanders soon nullifies any increase in supply. The increased supply is simply converted into a larger population. At that point the uncomfortable feeling of a shortage is reestablished, but this time at a higher level of population.

"So what?" one might ask: "if the feeling is the same, is the situation made any worse by an increase in population?" Yes, it is: the explanation follows from what the 19th century chemist Justus von Liebig called "limiting factors," the discussion of which can be made somewhat clearer by using the economists' term "production factors."


In the late 1980s, when the rich people of the world were made suddenly aware of starvation taking place in Ethiopia, a massive attempt was made to get food to the starving people. Sales from a popular record, "We Are the World," channeled $4.5 million into the effort. The justification of this campaign had many prongs: one was the ethical idea of the "sanctity of life." In practice, this concept led to the assertion that everything possible should be done to prevent loss of life from starvation. Food was airlifted into Ethiopia. As happens in all crisis-driven undertakings much waste ensued, but citing this fact does not constitute a fundamental criticism because no doubt some lives were saved. So why look askance at the charitable activity?

An ecological economist views the problems of poor countries in the following way. In a country like Ethiopia there are three major production factors: cropland, pasture land, and forest land. Cropland produces human food directly. Pasture land produces human food indirectly, through the conversion of (inedible) grass into (edible) meat and milk. The third production factor, forest land, is land that produces woody plants-bushes as well as trees-anything that can serve as fuel in the cooking of food.

In an ecologically balanced economy, these three production factors keep the people well-nourished without the factors themselves being degraded over time. The people live within the carrying capacity of their environment. But people starve when the supply of food generated by these production factors is less than the demand for food created by a too large population. In a "state of nature," i.e., when there are no inputs of food from the outside and the people are dependent only on their own productivity, an excess of population is soon corrected by excess mortality. For thousands of years local overpopulation was rectified in this way. In those days of poor communication and slow and expensive transportation there was really no other option.

Today electronic satellites and television make it possible to see - instantaneously - people starving to death on the other side of the world; and modern transportation has greatly increased the speed and lessened the cost of sending food to the needy. The fashionable saying, "Life is sacred," is interpreted as meaning that the preservation of the life of each and every human being is a prime imperative, overriding all other considerations. Most people regard the saving of the lives of strangers at a great distance as a morally noble by-product of scientific progress.

But when time is taken into consideration it can be shown that such a "noble" act is counterproductive of its implicit aim which, surely, is to minimize the total amount of human suffering over time. The admirable impulses of the traditional moralist must be confronted with the ecologist's time-shackled question, "And then what?"

With a few or no exceptions close examination of the economy of nations that chronically suffer from starvation reveals that the production factors are already severely over-stressed. In Ethiopia, land that should not be farmed is farmed, with a resultant loss of soil; too many animals are kept on the pasture lands, leading to the loss of soil and the replacement of "sweet grass" by weeds; and bushes and trees are removed from steep slopes resulting in a loss of soil that ultimately makes the reestablishment of woody plants impossible. (Internationalists should note that soil lost from the mountains of Ethiopia becomes silt in Egypt's Lake Nasser, thus shortening the useful lifetime of the High Aswam Dam.) When a country is overpopulated-when its population is greater than the carrying capacity of its land, whatever standard of living is used in reaching a judgementsaving lives today by direct gifts of food ensures that more lives will be lost tomorrow because of the increased environmental destruction made possible by the encouragement of population growth. The time-blind ideal, "Human life is sacred," is counterproductive.

"'Sacred," like all old words, has many meanings and connotations. What we are concerned with here is its related meaning of sacrosanct or inviolable. When disputants say that human life is sacred they clearly mean that we should preserve every human being now living regardless of the cost, either now or in the future. Though not given to using emotionally charged words, an ecologist would be more inclined to say that the environment, not human beings, is sacrosanct. The moment this proposition is advanced the conventional moralist expostulates: "Oh! You mean you prefer the life of dickey-birds to human beings? You prefer redwood trees to people?"

We have all heard such contemptuous questions. The questioner misses the point. Ecologists confer sacrosanctity on the carrying capacity of the environment in order to better the condition of men and women in the continuing future. When an ecological moralist proposes an Eleventh Commandment, "Thou shalt not transgress the carrying capacity," he is trying to improve the quality of life over a long period of time. Redwood trees and dickey-birds are seen as the symbols of the good life for human beings. Environmental extremists may talk of an undefined intrinsic value of the environment, but we need not follow them down this dubious rhetorical path. When we recommend that Ethiopians refrain from overgrazing their pastures and overharvesting their woody mountains we need not demand that they worship the landscape, merely that they take thought of what the environment will have to offer their descendants. A time-sensitive system of ethics cannot be blind to environmental values.


The potential of exponential growth in the human population is a standing threat of human welfare. Until very recently, however, this threat was mitigated by the sporadic eruption of such crowd-diseases as dysentery, cholera and plague which, at their worst, could wipe out a quarter to a half of a population in a year or two. Crowd-diseases were the most important negative feedbacks of the Malthusian demostat.

Sanitation and modern medicine have greatly weakened the power of disease as an effective controller of population size. When external controls are eliminated, humanity must then face the problem of devising alternative controls that are internal to the species. In the past two centuries much effort has been expended looking for acceptable internal population controls-so far without much success. This daunting problem remains to be solved.

Early in the twentieth century Margaret Sanger braved ecclesiastical censure and persuaded the medical profession and the general public that contraception could serve moral ends. Birth control (later called "family planning") was seen as the answer to the population problem. Desires of individual women became entangled with community needs as people carelessly assumed that Birth Control = Population Control. Unfortunately, the equivalence is less than total.

The official goal of family planning is to make it possible for a woman to have the number of children she wants when she wants them. Promoters of family planning assiduously (and wisely, from a public relations point of view) avoid the issue of how many children a woman should have, this being regarded as her private business. So if a woman wants too many children (too many, from the community's point of view), family planners will help her get too many.

To keep from growing, a population must maintain equality between its birth and death rates. Individual fertility can safely vary somewhat so long as the total number of births equals the total number of deaths, on the average. Obviously it would be a miracle if the individual desires of women should automatically produce the proper birth rate from the community's point of view. Population control is a community need; birth control is a personal activity. There is no reason why the activity should automatically match the need. In fact, the equivalence is rarely found. Everywhere in the world, variable though death rates are, the average number of children desired is greater than the number needed to balance the death rate. That is why birth control should not be confused with population control. (Of course contraception makes population control easier to achieve.)

Despite this elementary fact, government and private foundations are still investing millions of dollars yearly looking for better methods of birth control under the aegis of "population research." The research itself may well be worth doing, but it sails under false colors because it gives the impression of grappling with a difficult problem that is in fact being evaded.

One of the most successful evasions has been the pseudo-theory known as the "demographic transition." Born in France in the 1930s, it dominated demographic thought for some forty years. In 1975 Michael Teitelbaum said that "ironically its explanatory power has come into increasing scientific doubt at the very time it is achieving its greatest acceptance by nonscientists." We are now into the 1990s and still the demographic transition dominates popular discussions of population. So what is this theory that has such power?

Curiously, there is no authoritative and clear exposition of the theory. The common feature of its several variants is the faith that if we just let population "have its head" a benign adjustment will necessarily take place: the birth rate will spontaneously drop to the level of the death rate and all will be well. So demographic transition theory is just one more evasion from the necessity of rigorous thinking about the problem of controlling human population growth.

A more explicitly antiMalthusian theory is what is called the "child survival hypothesis." This asserts (first) that poor people have too many children because their awareness of high infant mortality impels them to produce extra children as a form of insurance; and (second) that if outside interveners reduce infant mortality, the people's fertility will be correspondingly reduced also (because the insurance is no longer needed). Therefore the way to get poor nations to stop overbreeding is to make them so prosperous that they will spontaneously reduce their infant mortality to the modern low level. Is this true?

Data vary, and one cannot be sure that what happens in the initial decade of a program will continue. The most defensible conclusion is that made by a close study of population growth in Guatemala, namely that if the postulated response is indeed true, it will appear only a generation or two after infant mortality has been brought down. A miserably poor population that is doubling in size in 23 years or less cannot wait a generation or two for the asserted benefit to appear. Nonetheless, the child survival hypothesis is very popular because it justifies charitable acts that give much pleasure to the donors.


The recognition of limits leads to a pattern of thinking that is guided by the perception of longages of demand. After centuries of thinking in terms of shortages of supply we are apt to find the idea of longages of demand uncomfortably threatening. By contrast the presumption of shortages of supply easily leads to seduction by the laissez-faire conjectures of the demographic transition theory and the child survival hypothesis, both of which tell us that freedom is the best policy.

Without attempting any overall evaluation of laissez-faire theory we are now in a position to examine laissez-faire birth control (B.C.) as a demographic policy. It is easy to show that the value of a complex policy depends on the total milieu in which it operates. Two important situations can be distinguished.

(1) Laissez-faire B.C. + NO social welfare- Equilibrium

This is the equilibrium of the pure Malthusian demostatic system, which holds for animal species in general, and was true during most of historic time for the human species. Statistically speaking, couples who had too many children for the environmental resources at their command left fewer living, breeding descendants than did couples who bred less extravagantly. Under these conditions one did not have to anticipate a need for the social control of fertility because the laissez-faire system was self-correcting.

(2) Laissez-faire B.C. + Welfare State --- > Runaway Growth

When, as shown in equation (2), the state assumes responsibility for the survival of all children, no matter how imprudently conceived, the self-correcting capability of the Malthusian demostat is removed. The population then increases until universal misery takes over as the ultimate negative feedback. If welfare functions are held to be too precious to be abandoned, then laissez-faire in birth control must be abandoned. This is the bullet we hesitate to bite.

The reason for our hesitation is obvious: we don't want to give up any of our freedoms. We are loath to admit that accepting a benefit always involves costs of some sort. The benefit is absorbed into a closely-knit system of social arrangements. One of the most basic of ecological principles is this: We can never do merely one thing. The known "one thing" we achieved with the conquest of crowd diseases in the nineteenth and twentieth centuries conferred unquestioned benefits on humanity. Now we must ask, What compensatory sacrifices must we make if we are to continue to enjoy those benefits? This, in a nutshell, is the seldom defined "population question."

Until the present time, arithmorrhea and the elaboration of pleasant but unsupportable conjectures like the demographic transition theory and the child survival hypothesis have enabled us to evade thinking rigorously about population, but time is running out. After nearly two centuries of evasion will historical events finally force us to face the population question during the last decade of the twentieth century? I, for one, am eager to find out!