Biological vs Social Carrying Capacities
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CULTURAL CARRYING CAPACITY:
A biological approach to human problems
by Garrett Hardin
Science, like all human institutions, evolves. Earlier in
this century Einstein probably spoke for most of the scientists of his day
when he identified the inner force that drew him to scientific work: "I
believe with Schopenhauer that one of the strongest motives that lead men
to art and science is [the desire to] escape from everyday life with its
painful crudity and hopeless dreariness, from the fetters of one's own
evershifting desires. A finely tempered nature longs to escape from
personal life into the world of objective perception and thought"
Then came the Second World War and the Manhattan Project,
culminating on 6 August 1945 with the announcement of the bombing of
Hiroshima. Almost overnight scientists realized they could no longer
escape becoming involved with the "crudities" of the world. In December of
the same year, with Einstein's blessing, the Bulletin of the Atomic
Scientists was founded to explore the human implications of scientific
discoveries. From the day of its founding, this bulletin has, in the best
and truest sense, been a controversial journal. Never again would the
escapism of a Schopenhauer be quite so attractive to scientists.
Biologists preceded the physicists in discovering the
social perils of pursuing science wherever it might lead. By
mid-nineteenth century it was obvious that there were overlaps between the
territories claimed by biologists and theologians. Peace-lovers tried to
establish a demilitarized zone between two tribes, but it didn't work. In
1925 ideological warfare broke out in Dayton, Tennessee. The legal outcome
of the Scopes trial was ambiguous, though one philosopher, as late as
1982, maintained that "the evolutionists won a great moral victory" (Ruse
1982). A different conclusion was reached by the biologist and
evolutionist, H. J. Muller. Thirty-four years after the trial, this Nobel
laureate noted that the subject of evolution was almost entirely missing
from high school biology textbooks. He concluded that, practically
speaking, biologists had lost the battle in Dayton. On the centenary of
the Origin of Species Muller thundered, "One hundred years without
Darwinism are enough!" (Muller 1959).
The next quarter of a century showed that Muller was no
mere viewer-with-alarm (Nelkin 1977). During this period the "scientific
creation" movement was born. Subsequent successes of the creationists were
due in equal measure to their political skill and to the relative apathy
of professional biologists. Finally biologists became sufficiently
disturbed by what was happening to public education to fight creationists
in the courts. Judge William R. Overton's detailed and thoughtful
judgement against the creationists in Arkansas on 5 January 1982 foretold
the end of the creationists' dominance of the public debate (Montagu
That is history; but history should never be regarded as
mere "water under the bridge." As Santayana said: "Those who cannot
remember the past are condemned to repeat it" (Santayana 1905). For more
than a century, we biologists failed to do our civic duty by bringing home
to the general public the human significance of evolution through natural
selection. That which we sowed by a century's near total neglect of public
education, we richly reaped in the form of widespread anti-intellectualism
fostered by Bible-worshipping fundamentalists. Biology abounds in insights
that call for a massive restructuring of popular opinions. If the sad
history of Darwinism in the agora is not to be repeated again and again,
biologists must accept the responsibility of bringing their insights to
Among the more important biological concepts crying out
for public explication today is the idea of "carrying capacity."
Resistance to exploring its implications arises in part from the same
source as resistance to Darwinism, as illustrated by the following
quotations, one of which predates of the Origin of Species by more than
From the beginning of the nineteenth century, evolution
(though not natural selection) was "in the air." In 1837 Cardinal Nicholas
Wiseman, perhaps the most influential Roman Catholic in England, disposed
of human evolution with these words: "It is revolting to think that our
noble nature should be nothing more than the perfecting of the ape's
maliciousness" (Wiener and Noland 1957). Obviously the ground was well
prepared for the rejection of Darwin's ideas long before he wrote his
great book. Darwin's acute awareness of the opposition awaiting his theory
no doubt accounted for much of his long delay in publishing the Origin.
How vigorously that opposition expressed itself is well
shown by the oft-told story of the Huxley-Wilber-force debate (see,
interalia, Hardin 1959 and Brent 1981). Less spectacular, but no doubt
more typical, was the reaction of the Victorian lady who, on hearing about
Darwin's theory, expostulated: "Descended from the apes! My dear, we will
hope that is not true. But if it is, let us pray that it may not become
generally known!" (Dobzhansky 1955). It is natural that people committed
less to truth than to the stability of society should prefer taboo to
confrontation (Hardin 1978).
In what follows, I shall use the term man in the generic
sense, to apply to any and all members of the human species regardless of
sex. When so used, man is equivalent to the Latin homo rather than vir.
This usage is old-fashioned but, I think, aesthetically preferable to
expository hybrids of person—(as in personholes, an unhappy substitution
Even the most casual reading of the Bible shows that man
occupies a very special place in the Judeo-Christian view of the world.
Simply put, Darwin's great contribution to public thought was the idea
that man is an animal. Not one in a thousand of those who reject Darwinism
today do so because they have made a close study of the theory (as laid
out, for instance, in any of the standard university textbooks on
Darwinian evolution). On the contrary, their rejection has its roots in a
highly emotional reaction to the thought that human beings are truly
animals, answering to principles that govern all animals. Yet this
assumption is the foundation of all biological research into the nature of
The contrary assumption, as expressed by Cardinal Wiseman
and the anonymous Victorian lady, can be called the hypothesis of human
exemptionism, or exemptionism for short (Catton and Dunlap, 1978). The
exemptionist assumes, without proof, that men (and women) are exempt from
important laws that govern the behavior of other animals. Darwinians do
not deny that there are some aspects in which human beings are unique
among animals—for instance, in being able to argue about evolution! But
Darwinians put the burden of proof on those who make any particular claim
of the uniqueness of man.
At various times in the past man was said to be the only
animal that could use tools, make tools, communicate with others of his
kind, or conceptualize. Soon after each uniqueness was postulated some
nonhuman exception was found. Desperately seeking something unique about
their own species, apologists even looked for less laudable differentia.
On various occasions it was claimed that man was the only animal that made
war against his own kind, or that lied, or that committed murder or rape.
But again, as fast as negative qualities were put forward, animal
exemplars were found.
In the end a few unique human abilities were found. (No
other animal conjugates verbs or declines nouns.) But the kinship of man
and the animals (meaning "other animals") remains a fruitful working
hypothesis for biologists. This hypothesis is recommended to scholars of
all persuasions as a sovereign remedy against deceptions engendered by
exemptionist thinking. In the end we find that man is indeed a remarkable
animal. There is no need to hamstring research at the outset by a
commitment to exemptionism.
CARRYING CAPACITY IN A NONHUMAN SETTING
The management of herds, both wild and domesticated, rests
on the concept of carrying capacity. A brief account of David R. Klein's
classic study of the reindeer on an Alaskan island will serve to
illustrate what carrying capacity means (Klein 1968).
In 1944 some two dozen reindeer were released on St.
Matthew Island where previously there had been none. Lichens were
plentiful and the animals increased at an average rate of 32% per year for
the next 19 years, reaching a peak of about 6,000 in the year 1963. During
the heavy snows of 1963-64 almost all of the animals died, leaving a
wretched herd of 41 females and 1 male, all probably sterile. It was not
so much the inclement weather that devastated the herd as it was a
deficiency in food resources, a deficiency that had been brought about by
The carrying capacity of a territory is defined as the
maximum number of animals that can be supported year after year without
damage to the environment. After careful study Klein concluded that 5
reindeer per km2 was the carrying capacity of an unspoiled St. Matthew
Island. An animal census taken in 1957 gave 4 animals per km2. A further
32% increase during the ensuing year would have brought the population to
5.3 per km2, a transgression of the carrying capacity. Had the herd been
managed (which it was not), the number would have been kept somewhere near
the 1957 size, below 5 per km2.
In developing a policy for dealing with carrying capacity
transgressions we must answer two questions: (1) How precise a figure is
the stated carrying capacity? and (2) What are the consequences of
transgressing the carrying capacity?
CARRYING CAPACITY ESTIMATES: IMPRECISE
There is no hope of ever making carrying capacity figures
as precise as, say, the figures for chemical valence or the value of the
gravitational constant. On St. Matthew Island the growth of reindeer moss
is no doubt greater some summers than others. Certainly the availability
of lichens is much less in winter when they must be dug out from under the
snow. Then too there are secular variations in climate: the exceptionally
severe winter of 1963-64 might have been part of a long-term cycle. To
these variations must be added unavoidable variations in expert opinion.
As a result, any particular figure for carrying capacity has a substantial
element of the arbitrary in it. Should we refuse to build policy upon
arguable estimates? What would happen if we ignored all estimates of
The short answer is disaster. Whenever a population grows
beyond the carrying capacity, the environment is rapidly degraded; as a
result, carrying capacity is reduced in subsequent years. Uncontrolled,
the population continues to grow larger (for awhile) as the carrying
capacity grows smaller.
The details of transgression-disasters vary from one
situation to another, but some of the consequences are extremely common.
Overexploited edible plants are replaced by weeds previously rejected by
the exploiting herbivores. Soil that has been laid bare is eroded away;
this reduces local productivity in subsequent years. Soil turned into silt
fills reservoirs and clogs irrigation systems. Loss of the rain-absorbent
capability of soils produces faster runoff after rain, and more
devastating floods in lower areas. These effects are especially severe
when forests on steep slopes are destroyed.
The consequences of systematically exceeding the carrying
capacity are serious and, more often than not, irreversible even when the
territory is freed of excess animals. Reversibility may be possible on a
geological time scale of tens of thousands of years, but on the time scale
of human history such long-term reversibility is no cause for complacency.
The Tigris-Euphrates valley, ruined by mismanagement two thousand years
ago, is still ruined.
If ecologists were ever asked to write a new Decalogue,
their First Commandment would be: Thou shalt not transgress the carrying
capacity (Hardin 1976).
Because transgression is so serious a matter, the
conservative approach is to stay well below the best estimate of carrying
capacity. Such a policy may well be viewed by profit-motivated people as a
waste of resources, but this complaint has no more legitimacy than
complaints against an engineer's conservative estimate of the carrying
capacity of a bridge. Even if our concern is mere profit, in the long run
the greatest economic gain comes from taking safety factors and carrying
capacities seriously. Is it not time to change the meaning of the word
conservative to take account of a new variety, the ecological conservative
(Hardin 1985a)? The ecoconservative knows that time has no stop. Proflt
seekers who focus too sharply on the bottom line of today's ledger book
underestimate the consequences of time's arrow. To the ecologist, bottom
line conservatives are not true conservatives. (Unfortunately bottom line
conservatives now fill most of the positions on the White House staff.)
The ultimate goal of game management
is to minimize the aggregate suffering of animals.
CAPACITY STRATEGY VERSUS SANCTITY
When the numbers of an exploiting herd of animals shoot
past the carrying capacity of their environment, what should concerned
human beings do? The answer is simple: get rid of the excess fast. This is
the correct answer regardless of whether we are primarily concerned with
the well being of the animals themselves, or with human profits to be
derived from exploiting them.
Quite often the simplest and least cruel way to diminish
animal numbers is to shoot the excess. This rational solution has been
vigorously opposed since its espousal by Aldo Leopold in the 1930s (Flader
1974). In state after state, the public has had to be educated to see the
harm that deer do to themselves when their numbers become too great. Game
managers have been opposed by amateur but publicity-wise "animal lovers"
(who will henceforth be referred to without quotation marks). With the
best of intentions, animal lovers force state agencies to adopt remedies
that inevitably lead to more animal suffering. The ill-advised measures
include the following.
WINTER FEEDING. The carrying capacity of the land is
usually lower in winter than in summer. When a population is no longer
kept under control by predators, the numbers rise until there are too many
animals to survive a normal winter. The shipping of food to the herd
following winter storms prevents Nature's harsh but efficacious remedy for
overpopulation. When continued for several seasons, winter feeding
produces too many animals even for the summer season, and the environment
is subjected to year-round degradation.
TRANSPLANTING. Animal lovers, like some economists (Simon
1981), cannot accept the fact that the world has limits. Whenever the
media carry accounts of starving deer, someone is sure to propose that the
animals be forcibly moved to other areas that, curiously, are assumed to
be both suitable and underpopulated. When such experiments are carried
out, the results are invariably expensive and unsatisfactory.
ADOPTION. Wild horses (really feral horses) in the western
United States tug strongly at the heartstrings of animal lovers. Years of
political pressure, orchestrated by "Wild Horse Annie" Johnston, finally
compelled Congress to pass the Wild Free-Roaming Horses and Burros Act of
1971. This act forbids private citizens or commercial enterprises to kill,
capture, or harass wild equines on federal lands.
Wild horses increase by about ten percent per year, which
means a doubling of the population every seven years. Unfortunately, the
rate of increase of the grazing lands is a negative number. Something has
to give. So the Bureau of Land Management (BLM 1980) set up an "Adopt
A-Horse Program" to reduce the herds in an acceptable manner. A US
resident, after filling out an application form and paying $200 for a
horse or $75 for a burro, can pick up and transport (at his own expense)
an animal to take to his home property. If the adopter takes care of it in
an approved manner for one year he can then obtain title to it.
The animals are rounded up by combined ground and
helicopter crews. The psychic trauma of such a roundup is presumed,
without evidence or inquiry, to be less than the trauma of being shot. The
cost to the government of each animal adopted, after subtracting the
adoption fee collected was $400 in flscal year 1981, and $474 in fiscal
year 1982 (BLM 1982). Thus is the expense of unwanted cruelty commonized
(Hardin 1985b) .
How many Americans have a suitable horse lot, and the
money and the inclination to adopt a wild horse? The number is unknown.
How fast is the number of potential adopters increasing? With continued
urbanization the population of potential adopters is undoubtedly
shrinking. Meanwhile the wild horse population grows at plus ten percent
The working of the mind of the committed animal lover is
one of the wonders of nature. Light is thrown on this wonder by a
statement made in Florida in 1982, when a portion of the Everglades became
seriously overpopulated with deer. The state Game and Fresh Water
Commission recommended that the deer population of 5,500 be reduced by
killing 2,250 animals (41%). Reacting to this proposal a Florida attorney
sought a court injunction to protect the lives of innocent, helpless,
harmless, and otherwise happy creatures that have been placed on earth by
God to be free from the torment of man." He claimed that killing any of
the animals would amount to a "deprivation of the rights of the deer to
live freely and peacefully on earth, according to nature's order" (Florida
In other words, this attorney was extending into the
animal realm the idea of the "sanctity of life" that many ethicists accept
in the human realm. Ironically, this amounts to a denial of the
exemptionism that is usually supported by those who reject the conclusions
of biology. Curiously, the manner of the rejection is the exact opposite
of that practiced by biologists: animals lovers would endow animals with
the gifts usually reserved for human beings.
Animal lovers and professional biologists should be able
to agree on the ultimate goal of game management: to minimize the
aggregate suffering of animals. They differ in their time horizons and in
the focus of their immediate attention. Biologists insist that time has no
stop and that we should seek to maximize the wellbeing of the herd over an
indefinite period of time. To do that we must "read the landscape,"
looking for signs of overexploitation of the environment by a population
that has grown beyond the carrying capacity.
By contrast, the typical animal lover ignores the
landscape while focusing on individual animals. To assert preemptive
animal rights amounts to asserting the sanctity of animal life, meaning
each and every individual life. Were an ecologist to use a similar
rhetoric he would speak of the "sanctity of carrying capacity." By this he
would mean that we must consider the needs not only of the animals in
front of us today but also of unborn descendants reaching into the
Time has no stop, the world is finite, biological
reproduction is necessarily exponential: for these combined reasons the
sanctity strategy as pursued by animal lovers in the long run saves fewer
lives, and these at a more miserable level of existence, than does the
capacity strategy pursued by ecologically knowledge able biologists.
Thus do we have the paradox that the interests of an
animal species are best served by focusing attention on the environment
rather than the individual animals. The environment is taken as a "given,"
and the animal population is made to match the capacity of the
THE HUMAN CONTEXT: CULTURE AND CARRYING
So far as it is within our power we surely would like to
manage human populations under the ideal used for animals, namely, to
minimize suffering and maximize happiness over many generations. This
means that, for human populations as for others, the prime commandment
must be Thou shalt not transgress the carrying capacity.
Most of the principles worked out for populations of
nonhuman animals apply with little change to human populations. Carrying
capacity must take account of seasonal variations—hence Aesop's story "The
Ant and the Grasshopper." Long cycle secular variations may also be
important (though man, the inveterate optimist, seldom takes really
adequate account of future threats). And variations in expert opinion are
even greater when we deal with the human situation.
For nonhuman animals it seems reasonable to measure
carrying capacity in terms of resources available for survival. In
evaluating the human situation, however, we are not satisfied with so
simple a metric. We hold that "Man does not live by bread alone." We go
beyond the spiritual meaning of the Biblical quotation in distinguishing
between mere existence and the good life. This distinction, like so many
population-related ideas, was well understood by Malthus, who held that
the density of population should be such that people could enjoy meat and
a glass of wine with their dinners. Implicitly, Malthus's concept of
carrying capacity included cultural factors.
The good life, then, must include a reasonable (though
undefined) amount of luxury food (fresh vegetables, quality meats,
delicious drinks), clothing beyond that needed for mere conservation of
body heat, comfortable housing, adequate transportation, space heating and
cooling, electronic entertainment, vacations, etc., etc.
There is no agreed upon metric to which we can reduce the
various goods so that we can compare the level of living of one people
with another. There is, however, a useful partial measure. and that is the
units of energy used per capita year in the various countries.
Periodically the United Nations publishes a measure of
energy use, stated in terms of kilograms of coal equivalent per capita per
annum. Consider the following figures for the year 1982: Ethiopia, 31;
World, 1,823; United States, 9,431 (UN 1984). On a relative basis, setting
Ethiopia equal to unity, these become: Ethiopia, 1; World, 59; United
Admittedly, many real components of the quality of life
are left out of this energy measure, e.g., many aesthetic goods,
interpersonal goods, and perhaps even spiritual goods. Material energy
sources are, to a large extent, interconvertible as sources of material
goods and facilitators of immaterial goods. Wood can be burned to cook
food, burned to heat a house, or used to construct a house. Oil can cook
food, heat a house, or be used to create raw materials for an artistic
painting. Crude as it is, the measure of people's energy consumption at
least yields a first approximation to the material quality of their life.
The enjoyment of nonmaterial goods requires at least a
minimum of material well-being. On this crude measure, the average
inhabitant of the world is about 60 times as well off as an average
Ethiopian, while Americans are more than 300 times as well off. Anyone who
goes to Ethiopia and tries to live the life of an average Ethiopian will
conclude that these flgures cannot be far wrong.
Carrying capacity is inversely related to the quality of
life. When dealing with human beings there is no unique figure for
carrying capacity. So when a pronatalist asserts (Revelle 1974) that the
world can easily support 40 to 50 billion people—some ten times the
present population -- he need not be contradicted. If everyone lived on
the energy budget of the Ethiopians, the earth might support 60 times the
present population, or about 300 billion people.
The figure just given is only a crude estimate. In less
hospitable regions, e.g., in Lappland, energy must be used to produce more
clothing or space heating. In the Imperial Valley of California, energy
must be used for the importation and pumping of water. But such facts are
no more than the details that would be needed to refine the estimate of
the maximum possible population supportable by the earth—if such an
estimate is worth refining, which is doubtful.
In the physical sciences the most basic terms stand for
entities that are "conserved under transformations," that is for entities
that remain quantitatively the same when qualitatively changed. Mass and
energy are such conservative concepts. Without conservative concepts
intellectual anarchy takes over and analysis becomes impossible.
In bioeconomics carrying capacity plays a conservative
role. In the nonhuman world its application presents few problems.
Carrying capacity does not vary without cause; it does not increase in
response to need; it cannot be transgressed with impunity; and its
definition in particular circumstances presents no serious problem to the
well-informed. Such is the situation so long as we deal only with nonhuman
When we move to human populations, however, the situation
changes. The naive question, "What is the human carrying capacity of the
earth?" evokes a reply that is of no human use. No thoughtful person is
willing to assume that mere animal survival is acceptable when the animal
is Homo sapiens. We want to know what the environment will carry in the
way of cultural amenities, where the word culture is taken in the
anthropological sense to include all of the artifacts of human existence:
institutions, buildings, customs, inventions, knowledge. Energy
consumption is a crude measure of the involvement of culture. It may not
be the best measure possible, but it will do for a first approach.
When dealing with human problems, I propose that we
abandon the term carrying capacity in favor of cultural carrying capacity
or, more briefly cultural capacity. As defined, the cultural capacity of a
territory will always be less than its carrying capacity (in the simple
animal sense). Cultural capacity is inversely related to the (material)
quality of life presumed. Arguments about the proper cultural capacity
revolve around our expectations for the quality of life. Given fixed
resources and well-defined values, cultural capacity, like its parent
carrying capacity, is a conservative concept.
ECONOMISTS AND ECOLOGISTS IN CONFLICT
Suppose resources are not fixed? If by resources we mean
natural resources that are available for human use at a particular time,
at a particular stage in technological development, then resources have
not been firmly fixed during all of human history. The past two centuries
have seen the most spectacular increase in the resources actually
available for human use. Malthus, because he was not acutely aware of the
increase in carrying capacity going on in his time, was so unlucky as to
put forth a theory of population that was too static to suit the
economists of subsequent times, who are keenly aware of the effect of
technology on the resources effectively available to the human species.
A careful reading of Malthus's work shows that he
described what we would now call a cybernetic system in which negative (or
corrective) feedbacks keep the population fluctuating about a relatively
fixed set point (Hardin and Bajema 1978). The set point is, of course, the
carrying capacity of the environment. Unfortunately for Malthus's
reputation, the spectacular development of technology in the years after
1798 moved the set point steadily upward.
Biologists find no difficulty in fitting this new fact
into the Malthusian cybernetic scheme, but many economists and other
social scientists see the continued increase in available resources as
incompatible with Malthusian theory. The difference in opinion is closely
connected with a difference in the perception of time (Hardin 1985b).
Economics, the handmaiden of business, is daily concerned with
"discounting the future," a mathematical operation that, under high rates
of interest, has the effect of making the future beyond a very few years
essentially disappear from rational calculation. Told that petroleum
resources will, for all practical purposes, be exhausted in 20 years, the
biologist starts to worry, while the economist merely yawns. For most
economic planning, the ultimate horizon of time is only five years away.
The economist can give two rather telling arguments for
continuing to refuse to take seriously any predictions of the state of the
world more than five years from now. First, for more than two centuries
science has come up with one miracle after another, steadily increasing
the functional carrying capacity of the world.
WHY SHOULD SCIENCE NOT CONTINUE TO DO
Scientists see less of the miraculous in the development
of technology. I am afraid that many economists see
"Science-and-Technology" as a magician with a bottomless hat out of which
an endless series of rabbits can be pulled. Economists have difficulty
taking energy shortages seriously. They say: "First we had wood for fuel.
As that became exhausted, we found we could use coal. Before that became
exhausted, we discovered oil. As we began to worry about the supply of
that, we discovered atomic energy. It looks like atomic energy is
inexhaustible; but if it isn't, why worry? Scientists will discover
something else; and just in time, as they always have in the past." Such
faith may be heartwarming, but it is also dangerous.
Economists have advanced another excuse for never worrying
(Simon 1981), which is rather subtle and more difficult to deal with.
Quoting Aesop, they maintain that "Necessity is the mother of invention."
This is certainly at least a half-truth. But some economists go on to
imply that the greater the necessity, the greater the inventiveness. This
may be seriously doubted. In our time, necessity is greatest in wretchedly
poor countries like Bangladesh and Ethiopia; but is inventiveness at its
maximum in such poor countries? Certainly not.
The stimulus of necessity is most effective when the
standard of living includes a considerable surplus of resources (luxury)
available for investment in the chancey activities of investigation,
invention, and testing.
Put another way, when the scale of living falls so far
below the cultural carrying capacity as to preclude effective
inventiveness—when the cultural capacity is seriously transgressed—then
living conditions spiral downward as the good life degenerates into mere
existence sans inventiveness. Translated into human terms, the ecological
first commandment becomes: Thou shalt not transgress the cultural
ONE WORLD OR MANY?
To whom is the first commandment of ecology addressed: to
the whole world acting as a unit, or to subdivisions of the world? Is it
wise to hope and plan for One World, a world without borders? Or must our
plans assume the continuation of subdivisions something like the nations
we now know? This is perhaps the most fundamental political question of
our time. The insights of biology are needed to solve it.
The dream of One World has ancient roots. Buddha, born
more than half a millennium before Christ, took a universalist position.
He seems to have had little direct influence on the development of Western
thought. Diogenes, in the fourth century BC, rejected mere patriotism,
calling himself kosmopolites, a citizen of the world. Zeno of Citium, in
the next century, committed Stoicism to the same ideal. Christianity
apparently derived this universal ideal from the Stoics. Though parishes
developed as a valuable administrative unit of the church, the guiding
ideal of Christianity has departed more and more from parochialism (L.
parochia, diocese or parish).
During the past century the production of literature
extolling One World has been a "growth industry." For this there are two
reasons, one good and one bad (or at any rate, insufficient). The good
reason has its roots in the consequences of the growth of population and
technology. Population growth shrinks the regions between competing
sovereignties and brings us every day closer to "living in each other's
pockets." Technology, ever more puissant in both war and peace,
exacerbates the consequences of propinquity. The mounting dangers of such
commonized disasters as acid rain, the greenhouse effect, and the nuclear
winter make anybody's business everybody's business. A purely localized
solution to such problems is no solution at all. When it comes to the
commons of water and air, we truly live in One World, whether or not we
are clever enough to make the appropriate political adjustments.
The insufficient reason for the decline of parochialism in
our time arises from a philosophical error. Wealth comes in only three
forms: matter, energy, and information. The first two forms obey
conservation laws: their exchanges are of the zero-sum sort. What Peter
gains, Paul loses. When it comes to material wealth, selective forces
operate against generosity and in favor of self-interest.
By contrast, exchanges of information are not bound by
conservation principles: positive-sum outcomes are possible. The
information that Peter gives to Paul does not make Peter the poorer.
Moreover, Paul may operate on that information, later handing it back to
Peter in improved form. That's a plus-sum relationship. Within limits,
selection favors cautious generosity and disfavors extreme selfishness
when it comes to the wealth of information. Other things equal, when it
comes to the distribution of information, a world without borders should
be a richer world than one divided into tight-lipped parishes.
Nowhere has the rejection of parochialism been stronger
than in the world of science and scholarship generally. Those who deal
primarily with ideas may quite unconsciously generalize the plus-sum
property of information exchanges into the domains of matter and energy,
where it does not apply. It is not uncommon for dealers in information to
naively suppose that Karl Marx's "From each according to his ability, to
each according to his needs" (Marx 1972) is a wise rule to follow in
exchanges involving matter and energy (as well as information).
I believe I have shown in "The Tragedy of the Commons"
(Hardin 1968) that the promiscuous sharing of matter and energy leads to
universal ruin. The argument may be restated in new and more biological
terms. If discrete entities (nations, for example) are in reality
competing for scarce resources, those entities that follow Marx's ideal
will be at a competitive disadvantage competing with more self-seeking
entities. The selective value of Marx's ideal is negative, so long as the
number of administrative entities is greater than one.
But what if there is only one administrative unit? What if
we succeed in creating the One World yearned for by Christians, Marxists,
and countless other groups? Never mind that many keen minds have regarded
this possibility as being highly improbable. What if...?
Bertrand Russell has given the answer. To survive as a
cohesive unit, an entity must be held together by some sort of cohesive
force. Says Russell: "Always when we pass beyond the limits of the family
it is the external enemy which supplies the cohesive force....A world
state, if it were firmly established, would have no enemies to fear, and
would therefore be in danger of breaking down through lack of cohesive
force" (Russell 1949). The writers of science fiction have long been aware
of this, repeatedly creating a scenario that brings the nations of the
world into a genuine union through the threat of enemies from outer space.
Unfortunately, all experience with space, to date, has given us no hope of
discovering such enemies. So the problem One World or Many? remains with
I have argued elsewhere (Hardin 1982) that no single way
will suffice to administer the affairs of what some people call "Spaceship
Earth." There must be some sort of fragmentation of administrative tasks,
though a universal approach is needed for the protection of the commons of
air and water. But most material wealth is, after all, fragmented around
the world; parochial distribution calls for parochial controls. This
logical necessity meshes well with the territorial instincts that have
been selected for during millions of years of biological evolution. How
the necessary "mixed economy" of administration is to be created and
sustained is an enormous problem.
In the meantime, whether or not we discover how to
administer the commons of air and water, we must clarify our thoughts
about the impact of competitive living on cultural carrying capacities. As
before, let us allow per capita energy use to deputize for the total
standard of living. This is an oversimplification of the real world, but
the consequences deduced are general and would hold up under a more
In making comparisons of one group of people with another
it is difficult to attain objectivity, because we are one of the world's
groups and we have varying relations with all the others. It will help, I
think, if we use the intellectual device of the "man from Mars," the
observer who can be perfectly objective about earthly affairs because he
has no terrestrial ties.
The man from Mars makes a tour of the earth and notes the
widely varying standards of living and the widely varying densities of
population. He also notes that resources vary widely in their
distribution. Having evolved by natural selection on Mars—is there any
other way to evolve?—our martian (like earthlings) has strong territorial
feelings. He points out that a parochial distribution of resources should
be matched by parochial consumption. This general principle does not
preclude international trade when a particular resource is in very short
supply in a particular nation; by trading parts of their relative
surpluses, trading nations can mutually gain.
The per capita consumption of energy in Bangladesh is one
thirty-eighth as great as the world average. Spokesmen for the country
complain about this low energy income. (The material quality of life,
however measured, seems correspondingly low.) How should others react to
The standard earthly response is to say, "Bangladesh
suffers from shortages." Thus do earthlings demonstrate their
fellow-feeling for the Bangladeshi, even though this may be the only way
they do so. But what would the man from Mars say? Being under no felt
necessity to demonstrate fellow-feeling, he might well respond thus:
"Shortage, you say? Shortage of resources? If parochial resources are
being fully used, how can there be a shortage? Parochial demand should
match parochial supply. Why not say there is a longage in demand? Though
it may not be possible to increase supply, it is always possible to
decrease demand. You do this either by reducing people's expectations, or
by reducing the number of people who have expectations—which can always be
done by reducing the birth rate. (There is no necessity to increase the
Continuing, the man from Mars says: "If each Bangladeshi
enjoys only one thirty-eighth as much energy as the average earthling,
maybe there are 38 times too many people living in Bangladesh? Should we
not speak of a 'longage' of people, rather than a shortage of resources?
In principle, a longage is always soluble; a shortage may not be."
If Bangladesh reduced its present population of 104
million people by a factor of 38 it would have only 2.7 million people. It
is of interest to note that the state of Iowa has exactly the same area as
Bangladesh, but with only 2.9 million people. There are many significant
differences between the two areas, so not too much should be made of the
contrast in population. But the equivalence does show that the suggested
population for Bangladesh is not terribly unreasonable.
Adopting the martian principle that parochial demands
should match parochial supplies would eliminate one important excuse for
aggressive international actions. Implicitly thinking in One World terms
easily leads to the concept of poor or "have-not" nations. An excessive
passion for justice can then easily lead to the assertion that being poor
justifies corrective military action. In our thermonuclear world, is there
any justice that would justify embarking on an uncontrollable war?
By contrast, the carrying capacity approach results in
replacing the concept of a "have-not" nation with that of an
"overpopulation" nation. It's a rare piece of property that cannot support
a suitably small population in comfort. This does not mean that every
territory will have a helping of all the amenities of life: people who
live in Spitzbergen should not assert their right to tropical beaches, nor
people in Bali their right to skiing. The exceptional property that cannot
meet a minimum standard for human existence should have a zero population.
It makes no sense to say that every territory has a right to be occupied
by a human population. Some wretched territories now inhabited should be
Overpopulation can be corrected by means short of homicide
and war. The means is attrition, which means seeing to it that the birth
rate falls below the death rate (Hardin 1985b). This may be painful, but
it is not war. For members of the Western world, part of the pain of
adjustment of population to reality arises from the necessity of
reexamining and substantially modifying our concept of human rights. In
this reexamination, the deep concept of cultural carrying capacity must
play a central role.
Garrett Hardin, professor emeritus of human ecology at the
University of California, Santa Barbara, received the 1986 AIBS
Distinguished Service Award for his contributions in the field of ecology
and his long-time efforts to apply scientific methods to the ethical and
political dilemmas posed by population growth and resource depletion. This
is the text of his acceptance speech, given 10 August 1986 at the AIBS
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Carrying Capacity Network . FOCUS/Volume 2, No. 3, 1992
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