Reflections on Sustainability, Population Growth, and the Environment - part 4

by Prof. Al Bartlett

January, 1998

Laws relating to sustainability

Let us be specific and state that both "Carrying Capacity" and "Sustainable" imply "for the period in which we hope humans will inhabit the earth." This means "for many millenia."

Many prominent individuals have given postulates and laws relating to population growth and sustainability.

The two 'postulata' of Thomas Malthus

The reverend Thomas Malthus used these two assumptions as the basis of his famous essay two hundred years ago.

First, That food is necessary to the existence of man.

Secondly, That the passion between the sexes is necessary and will remain nearly in its present state. (Appleman, 1976)

Garrett Hardin's three laws of human ecology

These three laws of human ecology were given by Garrett Hardin. (Hardin 1993) These are fundamental, and need to be known and recognized by all who would speak of sustainability.

First Law: "We can never do merely one thing." This is a profound and eloquent observation of the interconnectedness of nature.

Second Law: "There's no away to throw to." This is a compact statement of one of the major problems of the "effluent society."

Third Law: The impact (I) of any group or nation on the environment is represented qualitatively by the relation:

I = P A T

Here P is the size of the population, A is the per-capita affluence, measured by per-capita annual consumption, and T is a measure of the damage done by the technologies that are used in supplying the consumption. Hardin attributes this law to Ehrlich and Holdren. (Ehrlich and Holdren 1971)

The suggestion may be made that Hardin's Third Law is too conservative. The Third Law suggests that I varies as Pn where n = 1. There are situations where the impact of humans increases more rapidly than linearly with the size P of the population. In these cases, n > 1.

Boulding's three theorems

These theorems are from the work of the eminent economist Kenneth Boulding. (Boulding 1971)

First Theorem: "The Dismal Theorem"- If the only ultimate check on the growth of population is misery, then the population will grow until it is miserable enough to stop its growth.

Second Theorem: "The Utterly Dismal Theorem" - This theorem states that any technical improvement can only relieve misery for a while, for so long as misery is the only check on population, the [technical] improvement will enable population to grow, and will soon enable more people to live in misery than before. The final result of [technical] improvements, therefore, is to increase the equilibrium population which is to increase the total sum of human misery.

Third Theorem: "The moderately cheerful form of the Dismal Theorem" - Fortunately, it is not too difficult to restate the Dismal Theorem in a moderately cheerful form, which states that if something else, other than misery and starvation, can be found which will keep a prosperous population in check, the population does not have to grow until it is miserable and starves, and it can be stably prosperous.

Boulding continues:

Until we know more, the Cheerful Theorem remains a question mark. Misery we know will do the trick. This is the only sure-fire automatic method of bringing population to an equilibrium. Other things may do it.

In another context, Boulding observed that:

The economic analysis I presented earlier indicates that the major priority, and one in which the United Nations can be of great utility, is a world campaign for the reduction of birth rates. This, I suggest, is more important than any program of foreign aid and investments. Indeed, if it is neglected, all programs of aid and investment will, I believe, be ultimately self-defeating and will simply increase the amount of human misery. (Boulding 1971, p. 361)

Abernethy's Axiom

Motivation, rather than differential access to modern contraception is a major determinant of fertility. Individuals frequently respond to scarcity by having fewer children, and to perceived improved economic opportunity by having more children. Contrary to the demographic transition model, economic development does not cause family size to shrink; rather, at every point where serious economic opportunity beckons, family size preferences expand. (Abernethy 1993b)

A) Foreign aid conveys to the recipients the perception of improving economic wellbeing, which is followed by an increase in the fertility of the recipients of the aid.

B) Migrations from regions of low economic opportunity to places of higher economic opportunity result in an increase in the fertility of the migrants that persists for a generation or two.