Reflections on Sustainability, Population Growth, and the Environment - part 2

by Prof. Al Bartlett

January, 1998

Carrying capacity

The term "carrying capacity," long known to ecologists, has also recently become popular. It "refers to the limit to the number of humans the earth can support in the long term without damage to the environment." (Giampietro, et. al. 1992) The troublesome phrase here is "without damage to the environment." One damages the environment when one kills a mosquito, builds a fire, erects a house, develops a subdivision, builds a power plant, constructs a city, explodes a nuclear weapon, or wages nuclear war. Which, if any, of these things takes place "without damage to the environment?"

The concept of carrying capacity is central to discussions of population growth. Since the publication of the original paper, the concept has been examined by Cohen in a book How Many People can the Earth Support? (Cohen 1995) Cohen makes a scholarly examination of many past estimates of the carrying capacity of the Earth, and concludes that it is not possible to say how many people the Earth can support. Furthermore, any calculated estimate of the carrying capacity of the Earth may be challenged and will certainly be ignored.

Human activities have already caused great change in the global environment. May observes that (May 1993):

...the scale and scope of human activities have, for the first time, grown to rival the natural processes that built the biosphere and that maintain it as a place where life can flourish.

Many facts testify to this statement. It is estimated that somewhere between 20 and 40 percent of the earth's primary productivity, from plant photosynthesis on land and in the sea, is now appropriated for human use.

An impact on the global environment of this magnitude is properly the cause for alarm.

We note that growing populations require growing numbers of jobs and growing rates of consumption of resources, and the satisfaction of these requirements is almost always at the expense of the carrying capacity of the environment.

The inevitable and unavoidable conclusion is that if we want to stop the increasing damage to the global environment, as a minimum, we must stop population growth.

It won't be easy. Jerome B. Wiesner was President of M.I.T. (1971-1980) and was Special Assistant for Science and Technology for Presidents Kennedy and Johnson. He made a very sobering observation about the conflict between the needs of humans and the needs of the environment if we are to maintain the carrying capacity of the Earth. (Wiesner 1989)

There are no clear-cut ways to reconcile economic growth with the measures needed to curb environmental degradation, stretch dwindling natural resources and solve health and economic problems.

So, instead of trying to calculate how many people the Earth can support, we should instead, focus on the question of why should we have more population growth. This is nicely framed in the challenge:

Can you think of any problem, on any scale, from microscopic to global,
 
Whose long-term solution is in any demonstrable way,
 
Aided, assisted, or advanced, by having larger populations
 
At the local level, the state level, the national level, or globally?

Denial of the population problem

There are prominent political leaders who believe that there is no population problem.

For example, when Jack Kemp, who was then the U.S. Secretary of Housing and Urban Development, was informed of a report from the United Nations that told of resource problems that would arise because of increasing populations, it was reported that he said, "Nonsense, people are not a drain on the resources of the planet." (Kemp 1992)

Malcolm Forbes, Jr. Editor of Forbes Magazine had a similar response to the reports of global problems resulting from overpopulation in both the developed and underdeveloped parts of the world. "It's all nonsense." (Forbes 1992)

Here are two presidential people who reject the notion of limits that are implied by the concept of sustainability. Their expressions are consistent with a prominent refrain in presidential politics: "We can grow our way out of the problems."

Contrast these two statements with the words of the biologist E.O. Wilson who has written that:

The raging monster upon the land is population growth. In its presence, sustainability is but a fragile theoretical construct. To say, as many do, that the difficulties of nations are not due to people but to poor ideology or land-use management is sophistic.

Population and the Environmental Protection Agency

The U.S. Environmental Protection Agency has done many constructive and beneficial things. The policies, actions, and leadership of the Agency are crucial to any hope for a sustainable society. In a recent report from the Agency, we read:

In view of the increasing national and international interest in sustainable development, Congress has asked the Environmental Protection Agency (EPA) to report on its efforts to incorporate the concepts of sustainable development into the Agency's operations.

The Report (EPA 1993) is both encouraging and distressing. It is encouraging to read of all of the many activities of the Agency which help protect the environment. It is distressing to search in vain through the Report for acknowledgment that population growth is at the root of most of the problems of the environment. While the Brundtland Report says that population growth is not the central problem, the EPA report avoids making this allegation. But the EPA report makes only a very few minor references to the environmental problems that arise as a direct consequence of population growth.

The EPA report speaks of an initiative to pursue sustainable development in the Central Valley of California:

where many areas are experiencing rapid urban growth and associated environmental problems...

A stronger emphasis on sustainable agricultural practices will be a key element in any long-term solutions to problems in the area.

There is no way that "A stronger emphasis on sustainable agricultural practices" can stop the "rapid urban growth" that is destroying farmland! An emphasis on agriculture cannot solve the problem. To solve the problems, one must stop the "rapid urban growth" which causes the problems. It is pointless to focus on the development of "sustainable agricultural practices" when agriculture will soon be displaced by the "rapid urban growth." However, if "A stronger emphasis on sustainable agricultural practices" means "stop the conversion of agricultural land to urban or other developments," then there is logic to the second of the statements.

With our present social and value systems, it is almost impossible to maintain agriculture in the face of urban population growth.

In speaking of the New Jersey Coastal Management Plan for the management of an environmentally sensitive tidal wetland, the EPA report says:

The project involves balancing the intense development pressures in the area with wetlands wildlife protection, water quality, air quality, waste management, and other environmental considerations.

"Balancing" sounds nice, but it needs to be recognized that "balancing" generally means "yielding to."

In the Pacific Northwest:

The EPA... is an active participant in these discussions, which focus on sustaining high quality natural resources and marine ecosystems in the face of rapid population and economic growth in the area.

These quotations of minor sections of the EPA report make it clear that the EPA understands the origin of environmental problems. Thus it is puzzling that the Agency so carefully avoids serious discussion of the fundamental source of so many of the problems it is called on to address.

In this thirty page report on the Agency's programs, the term "sustainable development" is mentioned hundreds of times, and population growth, the most important variable in the equation, is mentioned just these few times. It is as though one attempted to build a 100 story skyscraper from good materials, but one forgot to put in a foundation.

A proposal for the establishment of a "National Institute for the Environment" (1993) is being advanced. If the proposed institute is to be effective, its mission and charge must include, "Studying the demographic causes and consequences of environmental problems." This means "look at the numbers!"

The marginalization of Malthus

We have seen how major national and international reports misrepresent and downplay (marginalize) the quantitative importance of the arithmetic of population sizes and growth. The importance of quantitative analysis of population sizes was pioneered by Thomas Malthus two hundred years ago, ( Appleman 1976) but the attempted marginalization of Malthus goes on today at all levels of society.

In an article, "The Population Explosion is Over" Ben Wattenberg finds support for the title of his article in the fact that fertility rates are declining in parts of the world. (Wattenberg 1997) Most of the countries of Europe are (1997) at zero population growth or negative population growth, and fertility rates in parts of Asia, have declined dramatically. Rather than rejoicing over the clear evidence of this movement in the direction of sustainability, Wattenberg sounds the alarm over the "birth dearth" as though this fertility decline requires some immediate reversal or correction.

The most extreme case is that of Julian Simon who advocates continued population growth long into the future. Writing in the newsletter of a major think tank in Washington, D.C., Simon says:

We have in our hands now - actually in our libraries - the technology to feed, clothe, and supply energy to an ever-growing population for the next 7 billion years... Even if no new knowledge were ever gained...we would be able to go on increasing our population forever. (Simon 1995)

It has been noted that a spherical earth is finite, but a flat earth can be infinite in extent. So if Simon is correct, we must be living on a flat earth. (Bartlett 1996)

Living at the limit

As populations grow and demands on resources increase, an aspect of the problem that is often overlooked is the fact that there are major fluctuations in the ability of the environment to satisfy our needs. In the case of municipal water, if we build new subdivisions sufficient to consume the limiting maximum output of our of our municipal water supply in wet years, then in dry years we will be seriously short. When one is living at the limit of a renewable resource, small fluctuations in the annual yield of the resource can cause major dislocations. Prudence dictates that one should plan to consume no more water annually than the water supply can deliver during the dryest years. This problem is even more critical with world food supplies, which are very dependent on the vagaries of global weather patterns.

The world's worst population problem

Echoing a view expressed earlier by the Ehrlichs (Ehrlich 1992) Bartlett points out that because of the high per capita consumption of resources in the U.S., we in the U.S. have the world's worst population problem! (Bartlett 1997) Many Americans think of the population problem as being a problem only of "those people" in the undeveloped countries, but this serves only to draw attention away from the difficulties of dealing with our own problems here in the U.S. It is easier to tell a neighbor to mow his / her yard than it is for us to mow our own yard. With regard to other countries, we can offer family planning assistance on request, but in those countries we have no jurisdiction or direct responsibility. Within our own country we have complete jurisdiction and responsibility, yet we fail to act to help solve our own problem. In a speech at the University of Colorado, then U.S. Senator Tim Wirth observed that the best thing we in the U.S. can do to help other countries stop their population growth is to set an example and stop our own population growth here in the U.S.

There can be no question about the difficulty that we will have to achieve zero growth of the population of the U.S. An examination of the simple numbers makes the difficulty clear. In particular, population growth has "momentum" which means that if one makes a sudden change in the fertility rate in a society, the full effect of the change will not be realized until every person has died who was living when the change was made. Thus it takes approximately 70 years to see the full effect of a change in the fertility rate. (Bartlett & Lytwak 1995)

Population growth never pays for itself

There are many encouraging signs from communities around the U.S. that indicate a growing awareness of the local problems of continued unrestrained growth of populations, because population growth in our communities never pays for itself. Taxes and utility costs must escalate in order to pay for the growth. In addition, growth brings increased levels of congestion, frustration, and air pollution.

In recent years, several states have seen taxpayer revolts in the form of ballot questions that were adopted to limit the allowed tax increases. These revolts were not in decaying rust-belt states; the revolts have been in the states that claimed to be the most prosperous because they had the largest rates of population growth. These limits on taxes were felt to be necessary to stop the tax increases that were required to pay for the growth. Unfortunately the growth has managed to continue, while the schools and other public agencies have suffered from the shortage of funds.

How do we work on the local problem? Many years ago I was discussing population growth of Boulder with a prominent member of the Colorado Legislature. At one point he said:

"Al, we could not stop Boulder's growth if we wanted to!"

I responded:

"I agree, therefore let's put a tax on the growth so that, as a minimum, the growth pays for itself, instead of having to be paid for by the existing taxpayers."

His response was quick and emphatic:

"You can't do that, you'd slow down our growth!"

His answer showed the way: communities can slow their population growth by removing the many visible and hidden public subsidies that support and encourage growth.

The Tragedy of the Commons (Hardin 1968) makes it clear that there will always be large opposition to programs of making population growth pay for itself. Those who profit from growth will use their considerable resources to convince the community that the community should pay the costs of growth. In our communities, making growth pay for itself could be a major tool to use in stopping the population growth.