Albert A. Bartlett

Part Four: Laws of 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 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 )



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 Hardinís 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.



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 )



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.



The Laws, Hypotheses, Observations, and Predictions that follow are offered to define the term "sustainability." In some cases these statements are accompanied by corollaries that are identified by capital letters. They all apply for populations and rates of consumption of goods and resources of the sizes and scales found in the world in 1998, and may not be applicable for small numbers of people or to groups in primitive tribal situations.

These Laws are believed to hold rigorously.

The Hypotheses are less rigorous than the laws. There may be exceptions to some, and some may be proven to be wrong. Experience may show that some of the hypotheses should be elevated to the status of laws.

The Observations may shed light on the problems and on mechanisms for finding solutions to the problems.

The Predictions are those of a retired nuclear physicist who has been watching these problems for several decades.

The lists are but a single compilation, and hence may be incomplete. Readers are invited to communicate with the author in regard to items that should or should not be in these lists.

In many cases, these laws and statements have been recognized, set forth, and elaborated on by others.



First Law: Population growth and / or growth in the rates of consumption of resources cannot be sustained.

A) A population growth rate less than or equal to zero and declining rates of consumption of resources are a necessary, but not a sufficient, condition for a sustainable society.

B) Unsustainability will be the certain result of any program of "development," that does not plan the achievement of zero ( or a period of negative ) growth of populations and of rates of consumption of resources. This is true even if the program is said to be "sustainable."

C) The research and regulation programs of governmental agencies that are charged with protecting the environment and promoting "sustainability" are, in the long run, irrelevant, unless these programs address vigorously and quantitatively the concept of carrying capacities and unless the programs study in depth the demographic causes and consequences of environmental problems.

D) Societies, or sectors of a society, that depend on population growth or growth in their rates of consumption of resources, are unsustainable.

E) Persons who advocate population growth and / or growth in the rates of consumption of resources are advocating unsustainability.

F) Persons who suggest that sustainability can be achieved without stopping population growth are misleading themselves and others.

G) Persons whose actions directly or indirectly cause increases in population or in the rates of consumption of resources are moving society away from sustainability. ( Advertising your city or state as an ideal site in which to locate new factories, indicates a desire to increase the population of your city or state. )

H) The term "Sustainable Growth" is an oxymoron.


Second Law: In a society with a growing population and / or growing rates of consumption of resources, the larger the population, and / or the larger the rates of consumption of resources, the more difficult it will be to transform the society to the condition of sustainability.


Third Law: The response time of populations to changes in the human fertility rate is the average length of a human life, or approximately 70 years. ( Bartlett and Lytwak 1995 ) [ This is called "population momentum." ]

A) A nation can achieve zero population growth if:

a) the fertility rate is maintained at the replacement level for 70 years, and

b) there is no net migration during the 70 years.

During the 70 years the population continues to grow, but at declining rates until the growth finally stops.

B) If we want to make changes in the total fertility rates so as to stabilize the population by the mid - to late 21st century, we must make the necessary changes before the end of the 20th century.

C) The time horizon of political leaders is of the order of two to eight years.

D) It will be difficult to convince political leaders to act now to change course, when the full results of the change may not become apparent in the lifetimes of those leaders.


Fourth Law: The size of population that can be sustained ( the carrying capacity ) and the sustainable average standard of living of the population are inversely related to one another. (This must be true even though Cohen asserts that the numerical size of the carrying capacity of the Earth cannot be determined, ( Cohen 1995 ))

A) The higher the standard of living one wishes to sustain, the more urgent it is to stop population growth.

B) Reductions in the rates of consumption of resources and reductions in the rates of production of pollution can shift the carrying capacity in the direction of sustaining a larger population.


Fifth Law: Sustainability requires that the size of the population be less than or equal to the carrying capacity of the ecosystem for the desired standard of living.

A) Sustainability requires an equilibrium between human society and dynamic but stable ecosystems.

B) Destruction of ecosystems tends to reduce the carrying capacity and / or the sustainable standard of living.

C) The rate of destruction of ecosystems increases as the rate of growth of the population increases.

D) Population growth rates less than or equal to zero are necessary, but are not sufficient, conditions for halting the destruction of the environment. This is true locally and globally.


Sixth Law: ( The lesson of "The Tragedy of the Commons" ) ( Hardin 1968 ): The benefits of population growth and of growth in the rates of consumption of resources accrue to a few; the costs of population growth and growth in the rates of consumption of resources are borne by all of society.

A) Individuals who benefit from growth will continue to exert strong pressures supporting and encouraging both population growth and growth in rates of consumption of resources.

B) The individuals who promote growth are motivated by the recognition that growth is good for them. In order to gain public support for their goals, they must convince people that population growth and growth in the rates of consumption of resources, are also good for society. [ This is the Charles Wilson argument: if it is good for General Motors, it is good for the United States.] ( Yates 1983 )


Seventh Law: Growth in the rate of consumption of a non-renewable resource, such as a fossil fuel, causes a dramatic decrease in the life-expectancy of the resource.

A) In a world of growing rates of consumption of resources, it is seriously misleading to state the life-expectancy of a non-renewable resource "at present rates of consumption," i.e., with no growth. More relevant than the life-expectancy of a resource is the expected date of the peak production of the resource, i.e. the peak of the Hubbert curve. ( Hubbert 1974 )

B) It is intellectually dishonest to advocate growth in the rate of consumption of non-renewable resources while, at the same time, reassuring people about how long the resources will last "at present rates of consumption." ( zero growth )


Eighth Law: The time of expiration of non-renewable resources can be postponed, possibly for a very long time, by:

i ) technological improvements in the efficiency with which the resources are recovered and used

ii ) using the resources in accord with a program of "Sustained Availability," ( Bartlett 1986 )

iii ) recycling

iv ) the use of substitute resources.


Ninth Law: When large efforts are made to improve the efficiency with which resources are used, the resulting savings are easily and completely wiped out by the added resources consumed as a consequence of modest increases in population.

A) When the efficiency of resource use is increased, the consequence often is that the "saved" resources are not put aside for the use of future generations, but instead are used immediately to encourage and support larger populations.

B) Humans have an enormous compulsion to find an immediate use for all available resources.


Tenth Law: The benefits of large efforts to preserve the environment are easily canceled by the added demands on the environment that result from small increases in human population.


Eleventh Law: ( Second Law of Thermodynamics ) When rates of pollution exceed the natural cleansing capacity of the environment, it is easier to pollute than it is to clean up the environment.


Twelfth Law: ( Eric Sevareid's Law ); The chief cause of problems is solutions. ( Sevareid 1970 )

A) This law should be a central part of higher education, especially in engineering.

Thirteenth Law: Humans will always be dependent on agriculture.

( This is the first of Malthusí two postulata. )

A) Supermarkets alone are not sufficient.

B) The central task in sustainable agriculture is to preserve agricultural land.

The agricultural land must be protected from losses due to things such as:

i ) Urbanization and development

ii ) Erosion

iii ) Poisioning by chemicals


Fourteenth Law: If, for whatever reason, humans fail to stop population growth and growth in the rates of consumption of resources, Nature will stop these growths.

A) By contemporary western standards, Nature's method of stopping growth is cruel and inhumane.

B) Glimpses of Nature's method of dealing with populations that have exceeded the carrying capacity of their lands can be seen each night on the television news reports from places where large populations are experiencing starvation and misery.


Fifteenth Law: In every local situation, creating jobs increases the number of people locally who are out of work.

Sixteenth Law: Starving people don't care about sustainability.

A) If sustainability is to be achieved, the necessary leadership and resources must be supplied by people who are not starving.


Seventeenth Law: The addition of the word "sustainable" to our vocabulary, to our reports, programs, and papers, to the names of our academic institutes and research programs, and to our community initiatives, is not sufficient to ensure that our society becomes sustainable.


Eighteenth Law: Extinction is forever.




1 ) For the 1998 average global standard of living, the 1998 population of the Earth exceeds the carrying capacity of the Earth. ( Pimentel 1994 ) [ Cohen ( 1995 ) would probably debate this. ]


2 ) For the 1998 average standard of living in the United States, the 1998 population of the United States exceeds the carrying capacity of the United States. ( Abernethy 1993a ),

( Giampietro and Pimentel 1993 )


3 ) The increasing sizes of populations that result from population growth are the single greatest and most insidious threat to representative democracy.


4 ) The costs of programs to stop population growth are small compared to the costs of population increases.


5 ) For society as a whole, population growth never pays for itself. [ This is a consequence of the Tragedy of the Commons. ]

A ) In the U.S. in general, the larger the population of a city, the higher are the municipal per-capita annual taxes.

B ) Sales taxes generated by a large shopping center in a small town may make it appear that growth of the shopping center has earned more than its public costs, but these earnings are at the expense of the areas surrounding the town.

6 ) The time required for a society to make a planned transition to sustainability on its own terms, so it can live within the carrying capacity of its ecosystem, increases with increases in

i ) the size of its population

ii ) the rate of growth of its population

iii ) the society's average per-capita rate of consumption of new resources.


7 ) The rate ( S ) at which a society can improve the average standard of living of its people is directly related to the rate of application of new technologies ( T ) and is inversely related to the rate of growth ( R ) of the size of the population ( the fractional increase per unit time ), by a relation with the general properties of the equation,

S = T - A R + B

where A and B are positive constants.

A ) In places in the world in 1998, the value of R ( the rate of growth of population ) is so large that it is causing S to be negative. Said in other words:

a ) Population growth competes with and slows down the rate of improvement of the average standard of living and may cause the average standard of living to decline. In other words:

b ) Population growth interferes with economic growth.


8 ) Social stability is a necessary, but not a sufficient, condition for sustainability.

A ) Human freedoms depend on social stability.

B ) Armed conflict ( war ) cannot be a part of a sustainable society.


9 ) Social stability tends to be inversely related both to population size and density.


10 ) The per-capita burden of the lowered standard of living that generally results from population growth and from the decline of resources, falls most heavily on the poor.

11 ) When populations are growing, the rate of growth of the fraction of the population that is poor exceeds the rate of growth of the fraction of the population that is wealthy.


12 ) Environmental problems cannot be solved or ameliorated by increases in population or by increases in the rates of consumption of resources.

A ) All environmental problems would be easier to solve if the population were smaller and / or if the rates of consumption of resources were smaller.


13 ) Problems of shortages of non-renewable resources cannot be solved or ameliorated by population growth.


14 ) Regional efforts to solve problems caused by population growth will only enlarge the problems if population growth in the region is not halted.


15 ) In general, neither the environment nor agriculture can be enhanced or even preserved through compromises.

A ) Compromises and accommodations between the immediate needs of people and the long-term needs of the environment will generally be resolved in favor of people at the expense of the environment, as though people can exist independent of the environment. For the most part, compromises only reduce the rate of destruction of the environment or they increase the elegance with which the environment is destroyed.

B) Compromises between the demands of urban / industrial growth and agriculture will always result in the conversion of agricultural land to urban and industrial uses. The reverse conversion never happens.


16 ) The fractional rate of destruction of the environment that results from human activities will always exceed the fractional rate of increase of our knowledge and understanding of the environment.

A ) Every decision affecting the environment will have to be made with less than full knowledge of the risks and consequences of the decision.

B ) Much of our knowledge of the environment has come from the study of past mistakes.

C ) It will always be possible for persons to argue for the delay of the implementation of corrective measures to save or preserve the environment, by claiming that our information about the problems is incomplete.


17 ) By the time overpopulation and shortages of resources are obvious to most people, the carrying capacity has been exceeded. It is then almost too late to think about sustainability.

A ) It is difficult to know what to do once one realizes that the population of a society is too large.

B ) Long-range thinking, planning, and leadership, carried out with a full recognition of the laws of nature, is most urgently needed.


18 ) For countries with large populations, importing non-renewable natural resources demonstrates unsustainability: exporting non-renewable natural resources reduces the ultimate sustainable standard of living and / or the carrying capacity of the exporting country.


19 ) When a society is living at the limit with regard to renewable resources such as food or water, small fluctuations in the supply can have large negative effects on the society.


20 ) Because of the growing universal nature of world trade, the concept of "carrying capacity" is difficult to apply to a nation or region.

A ) Sustainability is a global problem.

B ) However, the approach to stainability must be sought on the local and national levels.

C ) If a local official speaks of his / her community being sustainable, it probably is not true.


21 ) Sustainable agriculture cannot be based on large annual energy inputs from fossil fuels, particularly petroleum.

i ) "The food system consumes ten times more energy than it provides to society in food energy." ( Giampietro and Pimentel 1993 )


22 ) Irrigation of farmland, as it has been practiced throughout history and up to the present time, cannot be sustained. ( Abernethy 1993a, p. 136 )

i ) The lands become poisoned with salts.


23 ) Hydroelectric power generated from reservoirs created by construction of large dams, cannot be sustained.

i ) The reservoirs fill with silt.



1 ) In order to moved toward a sustainable society, the first and most important effort that must be made is to stop population growth. This will require the initiation of major comprehensive educational, technical, and outreach programs in the areas of social responsibility, family planning, contraception, immigration, and resource use. To get things right, these programs must focus on the goal of stopping population growth and should not be diluted by omitting references to the numbers involved in understanding population growth. The greater the degree to which the carrying capacity has been exceeded, the more probable it is that coercion will become a factor in these programs.

2 ) The food chain is nature's equilibrium mechanism. It functions to prevent unlimited expansion of populations of flora and fauna. Primitive human societies were able to maintain approximately constant populations and to live within the carrying capacity of their ecosystems. The methods they used to maintain approximately constant populations were often cruel and inhumane. Technology has given many people the feeling that, through our own efforts, we are exempt from the cruel constraints of limited carrying capacities.

3 ) Ancient civilizations have vanished, in part because they grew too large and their size exceeded the carrying capacity of the ecosystems on which they depended for support.

a ) Education notwithstanding, civilizations today show considerable tendency to repeat the mistakes of earlier civilizations, but on a much larger scale.

b ) Growing international trade allows the developed countries to draw on the carrying capacity of the entire earth, often at the expense of underdeveloped countries.

4 ) The complete era of the use of fossil fuels by humans will be a vanishingly short fraction of the span of human existence on the Earth. ( Hubbert 1974 )

5 ) The supplies of all non-renewable resources will effectively expire when the costs ( in cash, in energy, in ecological and societal disruption ) of making available a quantity of the resource exceed the value of the quantity of the resource.

6 ) Comprehensive educational, technical, and outreach programs in the areas of efficient use of resources will be needed in order to help achieve sustainability.

7 ) A major use of technology is, and has been, to accommodate the growth of populations, and to remove the recognition of the importance of living within the carrying capacity of the environment. ( See Boulding's "Utterly Dismal Theorem" and Eric Sevareid's Law )

A ) This use of technology has had the effect of encouraging population growth.

B ) This use of technology inhibits an approach to sustainability.

C ) An essential condition for sustainability is that technology be redirected toward the improvement of the quality of life, especially for those whose quality of life is now low, and away from its present use to increase the quantity of life.



1 ) Peak world production of petroleum will probably happen before the year 2020. Peak production of coal and oil shale, may occur in the 21st Century. Other fossil fuels probably will not be available in globally significant quantities for more than a few decades into the 21st Century.

2 ) If replacements can be found for fossil fuels, especially for petroleum, it will require major technological breakthroughs.

3 ) Technological progress in the future is much more likely to be characterized by incremental advances than by breakthroughs, especially in the field of sources of energy.

4 ) The probability is very small that technological developments will produce new sources of energy in the next century, sources not already known in 1998, that will have the potential of supplying a significant fraction of the world's energy needs for any appreciable period of time.

5 ) The larger the global total daily demand for energy, the smaller is the probability that a new energy source or technology will be found that will have the potential of being developed sufficiently to meet an appreciable fraction of the global daily energy demand for any extended period of time.

6 ) The larger the global total daily demand for energy, the longer is the period of time that will be required for a new energy technology to be developed to the point where it will have the capacity of meeting an appreciable fraction of the global daily energy demand.

7 ) In the event that science and technology find a new source of large quantities of energy, the probability is high that the new source will be technologically very complex, with the result that it will be extremely costly to bring globally significant quantities of the new energy to the marketplace.

8 ) Children born in 1990 will not live to see 10% of the energy consumed in the U.S. generated by terrestrial nuclear fusion. ( Bartlett 1990 )

9 ) There will always be popular and persuasive technological optimists who believe that population increases are good, and who believe that the human mind has unlimited capacity to find technological solutions to all problems of crowding, environmental destruction, and resource shortages.

A ) These technological optimists are usually not biological or physical scientists.

B ) Politicians and business people tend to be eager disciples of these technological optimists.

10 ) Because population growth is only one of the factors that drives up the cost of living, the rate of increase of the cost of living will probably be larger than the rate of increase of population.

11 ) The rate of increase of the cost of living will be greater than the rate of increase of family income for a majority of families. This is what is called a "healthy economy."



1 ) Local and regional business and political leaders will continue to spend much of their working time trying to attract new industries and populations to their areas, and to spend a prominent few minutes a week complaining and wondering what to do about the consequent increases in taxes, pollution, congestion, crime, costs, etc.

2 ) Local and regional political and business leaders will continue to use the circular arguments of self-fulfilling predictions in order to generate local population growth. The circular argument proceeds as follows:

i ) Quantitative projections of the "inevitable" future population growth in the area are made.

ii ) Plans are made to expand the municipal or regional infrastructure to accomodate the predicted growth.

iii ) Bonds are issued to raise money to pay for the planned expansions of the infrastructure, and the infrastructure is expanded.

iv ) The bonds must be paid off on a schedule that is based on the projections of population growth.

v ) The political and business leaders will do everything in their power to make certain that the projected population growth takes place, so that the bonds can be paid off on schedule.

vi ) When this results in the needed population growth, the leaders who predicted the population growth will speak loudly of their foresight.

vii ) Go back to i ) and repeat.

3 ) Some political and business leaders will continue to want to throw away all manner of toxic waste by dumping the waste on the lands of low-income or underdeveloped people, in the U.S. or abroad.

4 ) Some business leaders will want to continue to manufacture hazardous materials whose sale in the U.S. is prohibited, so that these materials can be sold abroad.

5 ) Business and political leaders will continue to find it more attractive to promote growth than to promote sustainability.

A ) It is easy to talk about sustainability.

B ) It is difficult to make realistic constructive progress toward sustainability

C ) Business and political leaders are not attracted to the concept of limits as implied by the term "carrying capacity."

6 ) In the U.S., political "conservatives" will continue to be liberal in their policy recommendations in regard to rapid exploitation and use of the earth's renewable and non-renewable resources, with complete confidence that technology will be able to solve all of the consequent problems of shortages, pollution, and environmental degradation. Political "liberals" will continue to urge people to conserve and to protect the environment, to recycle, to use energy more efficiently, etc., i.e., to be conservative.

7 ) Entrepreneurs and politicians will continue to use the term "sustainable" for their own personal advantage in promotion of enterprises and programs, whether or not these enterprises and programs are sustainable or contribute to the creation of a sustainable society.

8 ) Many members of the academic research and education programs that focus on sustainability issues such as air pollution, global warming, etc. will continue their old ways of generating high per capita levels of pollution.

9 ) Many Americans will continue to deny the seriousness of the population problem in America and will focus their attention on population problems elsewhere. They may be motivated in this by their reluctance to accept the fact that immigration accounts for roughly half of the present growth of the population of the United States.

10 ) Many Americans will continue to believe that the environment in the U.S. can be preserved without the need of addressing the population growth in the U.S.

11 ) Many people who are active in matters relating to population problems will continue their efforts to ignore and to urge others to ignore the quantitative aspects of the population problem. They will continue to claim that the problems will be more effectively addressed if we focus our efforts on such worthy causes as population growth in other countries, foreign aid, human rights, justice, equity, education of women, the consumption of resources, the distribution of food, etc. Some will even claim that slow growth and sustainability are compatible.

12 ) Reports containing the word "sustainable" in their titles will continue to be produced at all levels of government, and these reports will continue to ignore population growth as the greatest threat to sustainability.

13 ) There will always be those who reject all limits to growth.

Part One: Introduction & Overview
Part Two: Population, Environment & Pseudo Solutions
Part Three: Democracy, Economy & Trade
Part Five: Where Do We Go From Here?
Acknowledgements & References


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