Distinguish Between Overpopulation And Under Population Case Study

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by Paul and Anne Ehrlich

Having considered some of the ways that humanity is destroying its inheritance, we can look more closely at the concept of "overpopulation." All too often, overpopulation is thought of simply as crowding: too many people in a given area, too high a population density. For instance, the deputy editor in chief of Forbes magazine pointed out recently, in connection with a plea for more population growth in the United States: "If all the people from China and India lived in the continental U.S. (excluding Alaska), this country would still have a smaller population density than England, Holland, or Belgium." *31

The appropriate response is "So what?" Density is generally irrelevant to questions of overpopulation. For instance, if brute density were the criterion, one would have to conclude that Africa is "underpopulated," because it has only 55 people per square mile, while Europe (excluding the USSR) has 261 and Japan 857. *32 A more sophisticated measure would take into consideration the amount of Africa not covered by desert or "impenetrable" forest. *33 This more habitable portion is just a little over half the continent's area, giving an effective population density of 117 per square mile. That's still only about a fifth of that in the United Kingdom. Even by 2020, Africa's effective density is projected to grow to only about that of France today (266), and few people would consider France excessively crowded or overpopulated.

When people think of crowded countries, they usually contemplate places like the Netherlands (1,031 per square mile), Taiwan (1,604), or Hong Kong (14,218). Even those don't necessarily signal overpopulation—after all, the Dutch seem to be thriving, and doesn't Hong Kong have a booming economy and fancy hotels? In short, if density were the standard of overpopulation, few nations (and certainly not Earth itself) would be likely to be considered overpopulated in the near future. The error, we repeat, lies in trying to define overpopulation in terms of density; it has long been recognized that density per se means very little. *34

The key to understanding overpopulation is not population density but the numbers of people in an area relative to its resources and the capacity of the environment to sustain human activities; that is, to the area's carrying capacity. When is an area overpopulated? When its population can't be maintained without rapidly depleting nonrenewable resources (or converting renewable resources into nonrenewable ones) and without degrading the capacity of the environment to support the population. In short, if the long-term carrying capacity of an area is clearly being degraded by its current human occupants, that area is overpopulated. *35

By this standard, the entire planet and virtually every nation is already vastly overpopulated. Africa is overpopulated now because, among other indications, its soils and forests are rapidly being depleted—and that implies that its carrying capacity for human beings will be lower in the future than it is now. The United States is overpopulated because it is depleting its soil and water resources and contributing mightily to the destruction of global environmental systems. Europe, Japan, the Soviet Union, and other rich nations are overpopulated because of their massive contributions to the carbon dioxide buildup in the atmosphere, among many other reasons.

Almost all the rich nations are overpopulated because they are rapidly drawing down stocks of resources around the world. They don't live solely on the land in their own nations. Like the profligate son of our earlier analogy, they are spending their capital with no thought for the future.

It is especially ironic that Forbes considered the Netherlands not to be overpopulated. This is such a common error that it has been known for two decades as the "Netherlands Fallacy." *36 The Netherlands can support 1,031 people per square mile only because the rest of the world does not. In 1984-86, the Netherlands imported almost 4 million tons of cereals, 130,000 tons of oils, and 480,000 tons of pulses (peas, beans, lentils). It took some of these relatively inexpensive imports and used them to boost their production of expensive exports—330,000 tons of milk and 1.2 million tons of meat. The-Netherlands also extracted about a half-million tons of fishes from the sea during this period, and imported more in the form of fish meal. *37

The Netherlands is also a major importer of minerals, bringing in virtually all the iron, antimony, bauxite, copper, tin, etc., that it requires. Most of its fresh water is "imported" from upstream nations via the Rhine River. The Dutch built their wealth using imported energy. Then, in the 1970s, the discovery of a large gas field in the northern part of the nation allowed the Netherlands temporarily to export as gas roughly the equivalent in energy of the petroleum it continued to import. But when the gas fields (which represent about twenty years' worth of Dutch energy consumption at current rates) are exhausted, Holland will once again depend heavily on the rest of the world for fossil fuels or uranium. *38

In short, the people of the Netherlands didn't build their prosperity on the bounty of the Netherlands, and are not living on it now. Before World War II, they drew raw materials from their colonies; today they still depend on the resources of much of the world. Saying that the Netherlands is thriving with a density of 1,031 people per square mile simply ignores that those 1,031 Dutch people far exceed the carrying capacity of that square mile.

This "carrying-capacity" definition of overpopulation is the one used in this book. *39 It is important to understand that under this definition a condition of overpopulation might be corrected with no change in the number of people. For instance, the impact of today's 665 million Africans on their resources and environment theoretically might be reduced to the point where the continent would no longer be overpopulated. To see whether this would be possible, population growth would have to be stopped, appropriate assistance given to peasant farmers, and certain other important reforms instituted. Similarly, dramatic changes in American lifestyle might suffice to end overpopulation in the United States without a large population reduction.

But, for now and the foreseeable future, Africa and the United States will remain overpopulated—and will probably become even more so. To say they are not because, if people changed their ways, overpopulation might be eliminated is simply wrong—overpopulation is defined by the animals that occupy the turf, behaving as they naturally behave, not by a hypothetical group that might be substituted for them. [p.p. 37-40, Paul and Anne Ehrlich, THE POPULATION EXPLOSION; Simon and Schuster, 1990. Phone: 212-698-7000]

Cairo, 5 - 13 September 1994
Weighing Relative Burdens on the Planet
by Paul Ehrlich

Concern about population problems among citizens of rich countries generally focuses on rapid population growth in most poor nations. But the impact of humanity on Earth's life support systems is not just determined by the number of people alive on the planet. It also depends on how those people behave. When this is considered, an entirely different picture emerges: the main population problem is in wealthy countries. There are, in fact, too many rich people.

The amount of resources each person consumes, and the damage done by the technologies used to supply them, need to be taken as much into account as the size of the population. In theory, the three factors should be multiplied together to obtain an accurate measurement of the impact on the planet*. Unhappily, Governments do not keep statistics that allow the consumption and technology factors to be readily measured—so scientists substitute per capita energy consumption to give a measure of the effect each person has on the environment.


In traditional societies—more or less in balance with their environments—that damage may be self-repairing. Wood cut for fires or structures regrows, soaking up the carbon dioxide produced when it was burned. Water extracted from streams is replaced by rainfall. Soils in fields are regenerated with the help of crop residues and animal manures. Wastes are broken down and reconverted into nutrients by the decomposer organisms of natural ecosystems.

At the other end of the spectrum, paving over fields and forests with concrete and asphalt, mining the coal and iron necessary for steel production with all its associated land degradation, and building and operating automobiles, trains and aeroplanes that spew pollutants into the atmosphere, are all energy-intensive processes. So are drilling for and transporting oil and gas, producing plastics, manufacturing chemicals (from DDT and synthetic nitrogen fertilizers to chlorofluorocarbons and laundry detergents) and building power plants and dams. Industrialized agriculture uses enormous amounts of energy—for ploughing, planting, fertilizing and controlling weeds and insect pests and for harvesting, processing, shipping, packing, storing and selling foods. So does industrialized forestry for timber and paper production.


Incidents such as Chernobyl and oil spills are among the environmental prices paid for mobilizing commercial energy—and soil erosion, desertification, acid rain, global warming, destruction of the ozone layer and the toxification of the entire planet are among the costs of using it.

In all, humanity's high-energy activities amount to a large-scale attack on the integrity of Earth's ecosystems and the critical services they provide. These include control of the mix of gases in the atmosphere (and thus of the climate); running of the hydrologic cycle which brings us dependable flows of fresh water; generation and maintenance of fertile soils; disposal of wastes; recycling of the nutrients essential to agriculture and forestry; control of the vast majority of potential crop pests; pollination of many crops; provision of food from the sea; and maintenance of a vast genetic library from which humanity has already withdrawn the very basis of civilization in the form of crops and domestic animals.


The average rich-nation citizen used 7.4 kilowatts (kW) of energy in 1990—a continuous flow of energy equivalent to that powering 74 100-watt lightbulbs. The average citizen of a poor nation, by contrast, used only 1 kW. There were 1.2 billion people in the rich nations, so their total environmental impact, as measured by energy use, was 1.2 billion x 7.4 kW, or 8.9 terawatts (TW)—8.9 trillion watts. Some 4.1 billion people lived in poor nations in 1990, hence their total impact (at 1 kW a head) was 4.1 TW.

The relatively small population of rich people therefore accounts for roughly two-thirds of global environmental destruction, as measured by energy use. From this perspective, the most important population problem is overpopulation in the industrialized nations.

The United States poses the most serious threat of all to human life support systems. It has a gigantic population, the third largest on Earth, more than a quarter of a billion people. Americans are superconsumers, and use inefficient technologies to feed their appetites. Each, on average, uses 11 kW of energy, twice as much as the average Japanese, more than three times as much as the average Spaniard, and over 100 times as much as an average Bangladeshi. Clearly, achieving an average family size of 1.5 children in the United States (which would still be larger than the 1.3 child average in Spain) would benefit the world much more than a similar success in Bangladesh.


Professor John P. Holdren of the University of California has generated an "optimistic" scenario for solving the population- resource-environment predicament. This envisages population growth halted at 10 billion a century from now, and rich nations reducing their energy consumption to 3 kW a head. His population target is feasible with modest effort, and the reduction in energy consumption could be achieved with technologies already in hand—given the necessary political will—and would produce an increase in the quality of life. This would provide room for needed economic growth in poor nations, which could triple their per-person energy use to 3 kW. Thus the gap between rich and poor nations would be closed, while the total world impact would increase from 13 TW to 30 TW (10 billion x 3 kW).

Will the environment a century hence be able to support 2.3 times as much activity as today? It's questionable, but perhaps with care it could, at least temporarily. Success would require a degree of cooperation, care for our fellow human beings, and respect for the environment that are nowhere evident now. But society has shown it can change rapidly when the time is ripe; let us hope that the United Nations International Conference on Population and Development will help ripen the time.

* * *

* The relationship is summarized in the classic I=PAT identity: Impact is equal to Population size, multiplied by per capita consumption (Affluence), in turn multiplied by a measure of the damage done by the Technologies chosen to supply each unit of consumption.

Mr. Paul R. Ehrlich is Bing Professor of Population Studies and Professor of Biological Sciences at Stanford University in the United States. His most recent books, both co-authored with his wife Anne, are "The Population Explosion" (Simon and Schuster, 1990) and "Healing the Planet" (Addison-Wesley, 1991). The feature originally appeared in Vol. 6, No.3, 1994 of "Our Planet". The views expressed herein do not necessarily reflect those of UNEP.

UNEP Feature 1994/8


STANFORD—Asserting that there is now a "brownlash" in the form of deceptive books and articles downplaying environmental problems, scientists from Stanford's Department of Biological Sciences challenged Julian Simon to bet on significant trends in the human future.

Simon, a professor of business administration at the University of Maryland, has repeatedly claimed that all environmental trends are positive and that "doomsaying environmentalists" are wrong. In the San Francisco Chronicle of Friday, May 12, he suggested environmentalists bet that "any trend pertaining to material human welfare" will get worse, since Simon writes they will "all" get better.

The Stanford scientists, ecologist Paul R. Ehrlich and climatologist Stephen H. Schneider actually challenged Simon to bet on 15 current trends whose direction is not positive now, betting $1000 that each will get worse over a ten year stretch into the future. They pledged themselves to be bound by the decision of "a panel of scientists chosen by the President of the National Academy of Sciences in 2005."

Among the negative trends they bet would continue were:

* Rising global temperature.
* Shrinking amount of cropland per person.
* Decline in amount of wheat and rice grown per person.
* Shrinking area of tropical moist forests.
* Decreasing oceanic fish harvest per person.
* Increasing number of people dying of AIDS.
* Declining human sperm count.
* Growing gap between rich and poor.

The Stanford scientists explained that they had chosen "15 trends to avoid the result of a statistical fluke" deciding the bet, as may well have happened in a previous bet on a minor issue marginally related to environmental quality.

They pointed out that the trends in their wager "are more relevant to human welfare than direct ones such as the prices of metals" and that deterioration in those trends "makes society increasingly vulnerable to severe negative impacts."

They concluded "We hope we lose all parts of the bet, and will be doing everything in our power to make that happen.

Sadly, the misinformation you are spreading, Mr. Simon, increases the chances we will win the bet—while humanity loses."

The complete text of the response sent to the Chronicle follows:

by Paul R. Ehrlich and Stephen H. Schneider

There is now a campaign of deceptive books and articles designed to persuade people that all is well on the environmental front. The basic message of this campaign is that some favorable trends show green concerns to be "doomsaying." Our basic message is that indirect trends such as those listed below are more relevant to human welfare than direct ones such as the prices of metals.

Julian Simon has been a leader in this campaign. He is best known for his belief that resources are infinite (he wrote in 1980 that the theoretical limit to the amount of copper that might be available to human beings was "the total weight of the universe"!) and that population can and should grow indefinitely. He's still at it ("Earth's Doomsayers are Wrong," Chronicle, May 12), this time citing a 1986 report prepared by social scientists for the National Academy of Sciences (NAS) that was subsequently protested by a substantial number of Academy scientists. Somehow he missed the 1994 statement from the NAS and 57 other national academies of science worldwide that contradicted his position.

He also ignored the 1993 "World Scientists' Warning to Humanity," signed by some 1700 leading scientists, including over half of all living Nobel Laureates in science, which reads in part: "A great change in our stewardship of the earth and the life on it is required if vast human misery is to be avoided and our global home on this planet is not to be irretrievably mutilated....A new ethic is required—a new attitude towards discharging our responsibility for caring for ourselves and for the earth. We must recongize the earth's limited capacity to provide for us. We must recognize its fragility....The scientists issuing this warning hope that our message will reach and affect people everywhere. We need the help of many."

It is impossible to say exactly how direct measures of human well-being will be impacted by the general deterioration of Earth's life-support systems. We know, however, that deterioration makes society increasingly vulnerable to severe negative impacts.

One of us (PRE) once made the mistake of being goaded into making a bet with Simon on a matter of marginal environmental importance (prices of metals). Simon says he still wants to make bets. We are thus now challenging Simon to bet on "trends" of much greater significance to long-term human material welfare.

We wager $1000 per trend that each of the following 15 continental and global scale indicators will change in the direction indicated ("get worse") over the next decade:

1. The three years 2002-2004 will on average be warmer than 1992-1994 (rapid climatic change associated with global warming could pose a major threat of increasing droughts and floods).

2. There will be more carbon dioxide in the atmosphere in 2004 than in 1994 (carbon dioxide is the most important gas driving global warming).

3. There will be more nitrous oxide in the atmosphere in 2004 than in 1994 (nitrous oxide is another greenhouse gas that is increasing due to human disruption of the nitrogen cycle).

4. The concentration of tropospheric ozone globally will be greater in 2004 than in 1994 (tropospheric ozone has important deleterious effects on human health and crop production)

5. Emissions of sulfur dioxide in Asia will be signficantly greater in 2004 than in 1994 (sulfur dioxide becomes sulphuric acid in the atmosphere, the principal component of acid rain, and it is associated with direct damage to human health).

6. There will be less fertile cropland per person in 2004 than in 1994 (as the population grows, some of Earth's best farmland is being paved over).

7. There will be less agricultural soil per person in 2004 than in 1994 (about a quarter of the world's topsoil has been lost since World War II, and erosion virtually everywhere far exceeds rates of soil replacement).

8. There will be on average less rice and wheat grown per person in 2002-2004 than in 1992-1994 (rice and wheat are the two most important crops consumed by people).

9. In developing nations there will be less firewood available per person in 2004 than in 1994 (more than a billion people today depend on fuelwood to meet their energy needs).

10. The remaining area of tropical moist forests will be significantly smaller in 2004 than in 1994 (those forests are the repositories of some of humanity's most precious living resources, including the basis for many modern pharmaceuticals worldwide).

11. The oceanic fisheries harvest per person will continue its downward trend and thus in 2004 will be smaller than in 1994 (overfishing, ocean pollution, and coastal wetlands destruction will continue to take their toll).

12. There will be fewer plant and animal species still extant in 2004 than in 1994 (continuing habitat destruction is wiping out organisms that are the working parts of humanity's life-support systems).

13. More people will die of AIDS in 2004 than did in 1994 (as the disease takes off in Asia).

14. Between 1994 and 2004, sperm counts of human males will continue to decline and reproductive disorders to increase (over the last 50 years there has been a roughly 40 percent decline in the count worldwide. We bet this trend will continue due to the widespread use of hormone-disrupting synthetic organic chemical compounds).

15. The gap in wealth between the richest 10 percent of humanity and the poorest 10 percent will be greater in 2004 than in 1994.

We "doomsayers," of course, are not arguing that there are only unfavorable human or environmental trends, rather that too many of the most important are very unfavorable and thus demand prompt attention. Virtually all long-term trends have short-term fluctuations, thus we challenge Simon on 15 trends to avoid the result of a statistical fluke deciding this bet. To determine the direction of the trends, we will accept the decision of a panel of scientists chosen by the President of the National Academy of Sciences in 2005. Referees will be necessary, since terms like "significantly" (e.g., 5 and 10 above) and estimates of such things as agricultural soils involve questions of judgment. But there is an empirical basis on which competent scientists can make reasonable judgments.

The bet is binding on our heirs, and our winnings will go to non-profit organizations dedicated to preserving environmental quality and human well-being. Since humanity is gambling with its life-support systems, we hope to lose all parts of the bet.

In fact, we will be doing everything in our power to make that happen. Sadly, the complacency and misinformation you are spreading, Mr. Simon, increases the chances we will win the bet—while all of humanity loses. We hope this wager will cause you to reconsider the risks you so blythly suggest the American public undertake by promoting the fantasy of benign indefinite growth.

Paul R. Ehrlich and Stephen H. Schneider are Professors in the Department of Biological Sciences, Stanford University.

A review of:
by Herman Daly

This book is an all-out attack on neomalthusian or limits-to-growth thinking and a plea for more population and economic growth, both now and into the indefinite future. It is not a shotgun attack. Rather it is an attack with a single-shot rifle aimed at a single (but critical) premise of the neomalthusian position.

If Simon hits the target, then neomalthusian arguments collapse. If Simon misses the target, then all neomalthusian first principles remain unscathed, and Simon's progrowth arguments collapse. The critical premise that Simon attacks is that of the finitude of resources, including waste absorption capacities. Other premises from which neomalthusians argue include the entropy law and the vulnerability of ecological life-support services.

Simon's theoretical argument against the finitude of resources is that:

"The word "finite" originates in mathematics, in which context we all learn it as schoolchildren. But even in mathematics the word's meaning is far from unambiguous. It can have two principal meanings, sometimes with an apparent contradiction between them. For example, the length of a one-inch line is finite in the sense that it bounded at both ends. But the line within the endpoints contains an infinite number of points; these points cannot be counted, because they have no defined size. Therefore the number of points in that one-inch segment is not finite. Similarly, the quantity of copper that will ever be available to us is not finite, because there is no method (even in principle) of making an appropriate count of it, given the problem of the economic definition of "copper," the possibility of creating copper or its economic equivalent from other materials, and thus the lack of boundaries to the sources from which copper might be drawn."

Two pages later he drives home the main point in connection with oil:

"Our energy supply is non-finite, and oil is an important example . . . the number of oil wells that will eventually produce oil, and in what quantities, is not known or measurable at present and probably never will be, and hence is not meaningfully finite."

The fallacy in the last sentence quoted is evident. If I have seven gallons of oil in seven one gallon cans, then it is countable and finite. If I dump one gallon of oil into each of the seven seas and let it mix for a year, those seven gallons would no longer be countable, and hence not "meaningfully finite, " therefore infinite. This is straightforward nonsense.

The fallacy concerning the copper is obscured by the strange fact that Simon begins with a correct distinction regarding infinity of distance and infinity of divisibility of a finite distance, and then as soon as he moves from one-inch lines to copper with nothing but the word "similarly" to bridge the gap, he forgets the distinction. It would be a wonderful exercise for a class in freshman logic to find the parallel between Simon's argument and Zeno's paradox of Achilles and the tortoise. Recall that Zeno "proved" that Achilles could never catch up with a tortoise that had a finite head start on him. While Achilles traverses the distance from his starting point to that of the tortoise, the tortoise advances a certain distance, and while Achilles advances this distance, the tortoise makes a further advance, and so on, ad infinitum. Thus Achilles will never catch up.

Zeno's paradox confounds an infinity of subdivisions of a distance, which is finite, with an infinity of distance. This is exactly parallel to what Simon has done. He has confused an infinity of possible boundary lines between copper and noncopper with an infinity of amount of copper. We cannot, he says, make an "appropriate count" of copper because the set of all resources can be subdivided in many ways with many possible boundaries for the subset copper because resources are "infinitely" substitutable. Since copper cannot be simply counted like beans in a jar, and since what cannot be counted is not finite, it "follows" that copper is not finite, or copper is infinite.

Simon has argued from the premise of an "infinite" substitutability among different elements within a (finite) set to the conclusion of the infinity of the set itself. But no amount of rearrangement of divisions within a finite set can make the set infinite. His demonstration that mankind will never exhaust its resource base rests on the same logical fallacy as Zeno's demonstration that Achilles will never exhaust the distance between himself and the tortoise. Simon's argument therefore fails even if we grant his premise of infinite substitutability, which gets us rather close to alchemy. Copper is after all an element, and the transmutation of elements is more difficult than the phrase "infinite substitutability" implies! Indeed, Simon never tells us whether "infinite substitutability" means infinite substitutability at declining costs, constant costs, increasing costs, or at infinite costs! Of course Simon could simply assert that the total set of all resources is infinite, but this would be a bald assertion, not a conclusion from an argument based on substitutability, which is what he has attempted.

Simon appeals to the unlimited power of technology to increase the service yielded per unit of resource as further evidence of the essentially nonfinite nature of resources. If resource productivity (ratio of service to resources) were potentially infinite, then we could maintain an ever growing value of services with an ever smaller flow of resources. If Simon truly believes this, then he should join those neomalthusians who advocate limiting the resource flow precisely in order to force technological progress into the direction of improving total resource productivity and away from the recent direction of increasing intensity of resource use. Many neomalthusians advocate this even though they believe the scope for improvement is finite. If one believes the scope for improvement in resource productivity is infinite, then all the more reason to restrict the resource flow.

Those who are loud in their praise of Simon are the same people who would have bet on the tortoise, and are now betting on infinite resources. Simon's ultimate criterion for the validity of an argument seems to be willingness to "put your money where your mouth is." (See his grandstand offer on page 27 to bet anyone any amount, up to a $10,000 total, that the real price of any resource will not rise.) He suggests that the current heavy betting by speculators that the resource tortoise will stay ahead of the Achilles of demographic and economic growth is the best available evidence of the final outcome of the race. But it could in fact be the best available evidence that speculators are interested only in the short run, or that there is a sucker born every minute! In any case "put your money where your mouth is" is a challenge to intensity of belief, not correctness of belief. It is the adman's customary proof by bombastic proclamation.

But what about Simon's empirical evidence against resource finitude? It fares no better than his fallacious attempt at logical refutation. He leans heavily on two expert studies: "The Age of Substitutability" by Weinberg and Goeller (Science, February 20,1976), and Scarcity and Growth by Barnett and Morse.*1 His use of these studies is amazingly selective.

From Weinberg and Goeller he quotes optimistic findings of "infinite" substitutability among resources, assuming a future low-cost, abundant energy source. This buttresses Simon's earlier premise of "infinite" subdivisibility or substitutability among resources. But it does not lend support to his fallacious conclusion that resources are infinite and therefore growth forever is possible. More to the point, however, is that Weinberg and Goeller explicitly rule out any such conclusion by stating in their very first paragraph that their "Age of Substitutability" is a steady state. It assumes zero growth in population and energy use at the highest level that Weinberg and Goeller are willing to say is technically feasible. And they express serious reservations about the social and institutional feasibility of maintaining such a high consumption steady state.

Furthermore, the levels envisioned by Weinberg and Goeller, though cornicopian by general consent, are quite modest by Simon's standards: world population in the Age of Substitutability would be only 2.5 times the present population, and world energy use would be only 12 times present use. This implies a world per-capita energy usage of only 70 percent of current U.S. per capita use. The very study that Simon appeals to for empirical support of his unlimited growth position explicitly rejects the notion of unlimited growth—a fact that Simon fails to mention.

As further empirical evidence we are served a rehash of the Barnett an Morse study. Their finding was that the scarcity of most resources, as measure by per unit extractive costs and by relative prices, was decreasing rather than increasing from 1870 to 1957. Simon gives these arguments as evidence the resources are infinite.

There is no serious dispute about the Barnett and Morse numbers, but the conclusion that resources are becoming ever less scarce is hardly justified. The neomalthusians can reply that of course the prices of resources fall during a epoch of mineralogical bonanza. But the data cannot be decisive between these two views, since they cover only that epoch.

Barnett and Morse are careful to report an important exception to the general finding of falling resource prices: timber, whose price increased during the period. Simon's way of handling this exception is interesting. He first considers only mineral resources and applies the criterion of price as a measure of scarcity, explicitly rejecting all quantity-based indices. He thus shows, decline in scarcity of mineral resources. Later, in the context of food, he considers timber. This is a fair enough context, except that he switches his criterion of scarcity from price to quantity of timber growth. In this way he ca show decreasing timber scarcity by applying quantity measures, while showing decreasing minerals scarcity by applying price measures.

But an equally shifty neomalthusian could use quantity remaining in the ground to prove increasing scarcity of minerals, and relative price to prove increasing scarcity of timber. There is a serious debate about the proper measure of scarcity, as the report by Resources for the Future, Scarcity and Growth Reconsidered,*2 demonstrates, but Simon is not engaged in that serious discussion. He grabs whatever number may be moving in the direction that fits the needs of the argument at hand and baptizes it as an index of whatever he is talking about. Two examples will illustrate:

First, Simon claims, after warning us to "grab your hat," that pollution has really been decreasing rather than increasing. To test this hypothesis most investigators would probably look at parts per million of various substances emitted into the air and water by human activities to see if they have been rising or falling over time. Simon, however, takes life expectancy as his index of pollution: increasing life expectancy indicates decreasing pollution. If one suggests that the increase in life expectancy mainly reflects improved control of infectious diseases, Simon redefines "pollutant" to include the smallpox virus and other germs. In this way an increase in emissions of noxious substances from the economy (what everyone but Simon means by "pollution") would not register until after it more than offset the improvement in life expectancy brought about by modern medicine. Thus Simon "measures" pollution by burying it in an aggregate, the other component of which offsets and overwhelms it.

The second example is the claim (we are again told to grab our hats) that the combined increases of income and population do not increase "pressure" on the land. His proof: the absolute amount of land per farm worker has been increasing in the United States and other countries. One might have thought that this was a consequence of mechanization of agriculture and that the increasing investment per acre in machinery, fertilizer, and pesticides represented pressure on the land, not to mention pressure on mines, wells, rivers, lakes, and so on.

Simon's demonstration that resources are infinite is, in my view, a coarse mixture of simple fallacy, omission of contrary evidence from his own expert sources and gross statistical misinterpretation. Since everything else hinges on the now exploded infinite resources proposition, we could well stop here. But there are other considerations less central to the argument of the book that beg for attention.

If, Simon notwithstanding, resources are indeed finite, then the other premises of the neomalthusians remain in vigor. The entropy law tells us not only that coal is finite, but that you can't burn the same lump twice. When burned, available energy is irreversibly depleted and unavailable energy is increased along with the dissipation of materials. If nature's sources and sinks were truly infinite, the fact that the flow between them was entropic would hardly matter. But with finite sources and sinks, the entropy law greatly increases the force of scarcity.

Although the words "entropy" or "second law of thermodynamics" remarkably do not occur once in a 400-page book on The Ultimate Resource, the concept is occasionally touched upon. There is a comment made in passing that marble and copper can be recycled, whereas energy cannot. This raises hopes that Simon may not be ignorant of the entropy law. These hopes are soon dashed when he softens the statement to "energy cannot be easily recycled." Later he tells us that "man's activities tend to increase the order and decrease the homogeneity of nature. Man tends to bring like elements together, to concentrate them."

That is the only part of the picture that Simon knows about. But the entropy law tells us there is another part—that to increase order in one part of the system requires the increase of disorder elsewhere, and that in net terms for the system as a whole the movement is toward disorder. In other words, more order and more matter and energy devoted to human bodies and artifacts mean less matter and energy and less order for the rest of the system, which includes all the other species on whose life-support services we and our economy depend. Simon is quite prepared to ruin the habitats of all other species by letting them (and future generations) bear the entropic costs of disorders that our own continuing growth entails. For Simon, however, this problem cannot exist because he believes resources and absorption capacities are infinite. But after he has once mastered the paradox of Achilles and the tortoise concerning infinity, his next homework assignment should be to find out about entropy. Until he has done these two things he should stop trying to write books for grownups about resources and population.

Part II of the book is on population and is dedicated to the proposition that the ultimate resource is people. The more the better, indefinitely. We are told that: "Even the proposition that population growth must stop sometime may not be very meaningful (see Chapter 3 on 'finitude')." We have already seen Chapter 3 on finitude and have discovered that it is sheer nonsense. I will spare the reader a recitation of all the propositions about population that self-destruct with the demise of Chapter 3.

There is a puzzling methodological inconsistency between Parts I and II. In Part I Simon is the total empiricist, trusting only in the extrapolation of recent trends of falling resource prices. Any a priori argument from first principles about reversal of trends due to increasing cost, diminishing returns, the end of a bonanza, or even the S-shape of the logistic curve characteristic of all empirically observed growth processes simply does not warrant consideration by this hard-headed empiricist. Yet in Part II we find Simon refusing to project population trends and relying on the theory of demographic transition to reverse the recent trend of population growth. His own graphs, used to demonstrate the unreliability of past population predictions, also show that a simple linear trend would have yielded much more accurate predictions in the 1920s than did the then current "twilight of parenthood" theories. Once again, whatever epistemological posture serves the immediate needs of argument is adopted. One is certainly free to choose whatever balance of theory and empiricism one thinks is most effective in getting at the truth, but the balance should not fluctuate so wildly, so often, and so opportunistically.

Simon values human life. More people are better than fewer people because each additional person's life has value for that person, his loved ones, and for society as a whole should he turn out to be a genius: an increase of 4,000 people is more likely to yield another Einstein, Mozart, or Michelangelo than an increase of only 400 people.

While I personally give zero weight to the notion that more births among today's poor and downtrodden masses will increase the probability of another Einstein or Mozart (or Hitler or Caligula?), I do agree that, other things equal, more human lives, and more lives of other species, are better than fewer. And I think that most of my fellow neomalthusians would agree than 10 billion people are better than 2 billion—as long as the 10 billion are not all alive at the same time!

This is the crucial point: neomalthusian policies seek to maximize the cumulative total of lives ever to be lived over time, at a sufficient per-capita standard for a good life. Simon wants to maximize the number of people simultaneously alive—and, impossibly, to maximize per-capita consumption at the same time. These two contradictory strategies are possible only if resources are infinite. If they are finite then maximizing the number of simultaneous lives means a reduction in carrying capacity, fewer people in future time periods, and a lower cumulative total of lives ever lived at a sufficient standard.

The difference is not, as Simon imagines, that he is "pro-life" and the neomalthusians are "anti-life." Rather it is that neomalthusians have a basic understanding of the biophysical world, whereas Simon still has not done his homework on Zeno's paradoxes of infinity, on the entropy law, on the importance of ecological life-support services provided by other species, and on the impossibility of the double maximization implied in his advocacy of "the greatest good for the greatest number."

Simon seems to believe that an avoided birth today implies the eternal nonexistence of a particular self-conscious person who would have enjoyed life. But as far as I know, the pairing of a particular self-consciousness with a particular birth is the greatest of mysteries. Perhaps birth control means that a particular existence is postponed rather than canceled. In other contexts, however, Simon proclaims that "birth control is simply a human right." When Kingsly Davis, Paul Ehrlich, or Garret Hardin advocate birth control they are sacrificing the unborn; but when Simon finds it convenient to his argument to endorse birth control, he is proclaiming a human right.

In this reviewer's opinion, Simon's book cannot stand up to even average critical scrutiny. Lots of bad books are written, and the best thing usually is to ignore them. I would have preferred to ignore this one, too, but judging from the publicity accorded Simon's recent articles, this book is likely to be hailed as a triumph by people who are starved for "optimism." Simon himself tells us that the optimistic conclusions he reached in his population studies helped to bring him out of a "depression of medically unusual duration," and he clearly wants to share the cure. But his cure is at best a sugar pill.

We must abandon the shallow, contrived optimism of growthmania once and for all. The end of growthmania is no cause for despair; it is a hopeful new beginning. To me the optimistic alternative is that of a steady state at a sufficient, sustainable level in which many future generations can rejoice in the loving study and care of God's creation.

Further prolongation of the current compulsive quest for infinite growth, power, and control is what I find depressing. We should learn to be good stewards of what is already under our dominion rather than seek always to enlarge that dominion. We who have done a poor job of managing a small domain should not trust ourselves to take over control of an ever larger "infinite" domain.

NOTE: This review appeared originally in Bulletin of the Atomic Scientists, January 1982.


1. Harold Barnett, and Chandler Morse, Scarcity and Growth (Baltimore: Johns Hopkins Press, 1963).

2. V. Kerry Smith, ed., Scarcity and Growth Reconsidered (Baltimore: Johns Hopkins Press, 1979).


The above review is from: [p.p. 282-289] STEADY STATE ECONOMICS, Daly; Island Press, 1991. ISBN 1-55963-071-X

Population and Natural Resources module: Conceptual Framework
AAG Center for Global Geography Education


Learning Objectives

 By completing this conceptual framework, you will be able to:


  1. Distinguish different theoretical approaches to the study of population and natural resources.
  2. Analyze the competing interests faced by human population growth and land availability and uses in different contexts. 
  3. Compare the environmental impacts of human population growth in different countries.
  4. Gain awareness of different international perspectives and approaches to natural resource management.



In the year 1900, there were approximately 1.6 billion people living on Earth. One hundred years later, the world population totaled just over 6 billion people. In 2011, the world total is likely to reach 7 billion, on its way to a projected 9 billion before 2050 (Figure 1). The increase in the size of the human population in the last half-century is unprecedented. But that increase did not occur evenly in different places, nor were the consequences of this growth the same in every place. And in the 21st century, some places are concerned more about population decline than growth.


This module examines the growth, decline, and movement of human populations over time and space, and how this affects the availability of resources such as food and water. Demography is the study of the characteristics of human populations, including fertility, mortality, and health. Geographers use demographic data to analyze the spatial variations in demographic characteristics and trends, linking these to their social consequences, seeking explanations for differences and solutions for inequalities. For example, geographers ask questions such as: Why do population growth rates vary from place to place? How does population growth affect the availability of resources at local, national, and global scales? How can countries achieve sustainable use of environmental resources? Is population control necessary to raise the quality of life in poorer countries? Are wealthy countries consuming a disproportionate share of the world's resources, thereby depriving people living in the more populous developing regions? These are just some of the issues you will consider in this module.


By completing this module, you will learn geographical techniques for measuring and comparing population change in different places. The module covers a wide variety of population theories and topics, including movement, urbanism, and resources, and how experiences in one country can be quite different from the experiences of people in other countries.  


Figure 1. Increase in World Population since 1750 (projected to 2050)(in thousands)

Data sources: United Nations (1999) and US Census Bureau (2008)


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Suggested citation: Conway-Gomez, K., Barton, K., Wang, M., Wei, D., Hamilton, M., and Kingsland, M. 2010. Population & Natural Resources conceptual framework: How does population growth affect the availability of resources? In Solem, M., Klein, P., Muñiz-Solari, O., and Ray, W., eds., AAG Center for Global Geography Education. Available from http://globalgeography.aag.org.

Images courtesy of the GeoCube project.

Population Growth


Later in this Conceptual Framework, you will explore major population theories of the 19th and 20th centuries and apply those theories to a set of specific historical circumstances (famine in Ethiopia). To provide context for this discussion, we turn first to a discussion of why population rates have "exploded" in recent history. We then look at a model that explains how and why population dynamics change in response to increased economic development.


Three "revolutions" in technology - the agricultural (approximately 6,000 BCE until 1,800 CE), industrial (beginning in the late-18th century), and "green" (beginning in the mid-20th century) – have affected population numbers and their interactions with natural resources (Figure 2). Notice, however, that the pace of world population growth dramatically increased following the Industrial Revolution, peaking in the years after World War II. From the mid-20th century, the world population began to increase at unprecedented rates, a phenomenon known as the "population explosion".




Figure 2. Impacts of Technological Revolutions on World Population Growth

Data sources: Population Reference Bureau (2003) and United Nations Population Division (1998)



The Green Revolution generated new techniques of crop production, including increased use of chemical fertilizers and the application of genetic engineering to crop research, making it possible to increase food production by dramatic rates.  During the 20th century large tracts of land, for example in the United States, were dedicated to the cultivation of grains with increased production and improved quantity and quality.  The same thing happened in countries like Argentina and Brazil from the beginning of the 20th century.  Rice production in East and southeast Asia increased at rates over even the peak rates of population growth experiences in the 1960s and 1970s. New technologies were also introduced to more effectively distribute food among people.  Furthermore, natural resources were found in much of the world and new agricultural technologies were developed. As you will see, this ability to produce more food challenged the "Malthusian" theory that limitations of agricultural production would lead to catastrophe if population growth went unchecked. 


Even though yields of certain crops in certain countries increased, a high percentage of the world's population today still lacks sufficient food. The main problem behind the numbers suffering from hunger lies in the distribution of food.  The current world population is increasing by nearly 80 million people per year. Hunger remains an issue for hundreds of millions of people in the world's least-developed countries.


Pause and Reflect 1:
Investigate socioeconomic data for the "Least Developed Countries" in the current World Population Data Sheet (at the PRB's website).
Where are these countries?

What explains their socioeconomic status?


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Measuring Population Change


Measuring population change is necessary to determine the impact of human activity on the Earth's surface.  Population change can be described using words, statistics, and graphics.  Two common statistical measures of population change are the Crude Birthrate (CBR) and the Crude Death Rate (CDR). CBR and CDR are usually expressed as the number of births or deaths per 1000 people in a given population, which allows geographers to compare population dynamics in countries with different population sizes.  The number of births and deaths per year in a country can be used to calculate the Rate of Natural Increase (RNI), which describes the percentage annual growth of a population. 


For example, suppose a country has a total population of 250 million people, with four million births and one million deaths over a year-long period. The Rate of Natural Increase for this country would be calculated as follows:


Birthrate per 1000 population = (Births per year/Total population) * 1000 = (4,000,000/250,000,000) * 1000 = 0.016 * 1000 = 16

Death Rate per 1000 population = (Deaths per year/Total population) * 1000 = (1,000,000/250,000,000) * 1000 = 0.004 * 1000 = 4


To convert these into the RNI, you subtract the CDR from the CBR and multiply by 10 (necessary to convert the data from a per 1000 basis to a per 100, or percentage, basis).


Rate of Natural Increase = (Birthrate - Death Rate) * 10 = (16 - 4) * 10 = 1.2%


Given a RNI of 1.2%, we can predict that the population of this country will grow by 3,000,000 people in one year (250,000,000 x 1.2% = 3,000,000).


As you might imagine, comparing population trends and patterns using only statistics would be very difficult.  Fortunately, there are ways to visualize statistical data to reveal meaningful geographic information.  Geographers use maps to display, analyze, and compare demographic data like CBR, CDR, and RNI in different places.  In the next activity, you will be asked to create choropleth maps to interpret population change in Bolivia, a country in South America.  The activity will also illustrate some of the possible effects of population growth on the environment.


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Spatial Thinking Activity: Mapping Population Data


View the following interactive presentation on choropleth mapping, which illustrates how to create maps from tables of population data. To start the activity, simply click the screen. You can advance through the presentation by clicking anywhere on the screen, or by moving your pointer to the left side to navigate a table of contents.  


After viewing the presentation, download this 4-page file: Population in Bolivia. These are worksheets from Activities and Readings in the Geography of the World (ARGWorld). Complete the worksheets and answer these questions: 

(1) Examine the map of Bolivia. In what part of Bolivia is population growth the slowest? The fastest?

(2) What reasons can you give for these patterns?  

(3) Does the map support the hypothesis that population growth is causing deforestation in some parts of Bolivia? Why or why not?

(4) What are the advantages of a spatial analysis of population data? What limitations do you observe?


The Shockwave plugin for your browser is required to view the activity. The plugin can be downloaded at no cost from http://www.adobe.com/products/shockwaveplayer/).Note: On the table of contents, ignore the buttons for Related Units and Exit to Main Menu. Once the plugin is installed, you may have to click to choose to allow active content or follow the browser directions to activate the active content.


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The Demographic Transition Model


The Demographic Transition Model (DTM) is a popular method for analyzing the evolution of the world population (Figure 3).  It shows the expected changes in birth and death rates over an unspecified timeframe. The DTM is based on the historical experience of Europe, as birth and death rates declined, beginning in the case of those nations in the late-18th and early-19th centuries. The only variables that are forecast by this model are birth and death rates, but many scientists believe that economic development is the major factor causing the birth and death rates to fluctuate. They argue that with economic development, people gain better access to birth control; public health and sanitation improves; women become more independent; and food and basic necessities become more plentiful. These improvements, in turn, increase life expectancy and eventually prompt women to have fewer children. 


What evidence is there to support the theory that economic development leads to a decline in death and birth rates?  Some population geographers point to the population histories of Western European countries as examples, where populations that once grew rapidly experienced a gradual decline and stabilization of birth and death rates as a result of improved food supplies, public health, and technology.  Historically, population changes in Western Europe corresponded to the four stages described on the next page.




Figure 3. The Demographic Transition Model

Source: InternetGeography (www.learnontheinternet.co.uk)


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Explaining the Demographic Transition Model


Here are the characteristics associated with each stage of the classic four-stage DTM. In parentheses, the approximate dates of the onset of each stage are shown as they occurred in Europe, but there was much variation even across that region, so these dates are approximate.


Stage 1: Both birth and death rates are high and population grows slowly, if at all (Europe between pre-history and about 1650).

Stage 2: Birthrates remain high, but death rates fall sharply as a result of improved nutrition, medicine, health care, and sanitation.  Population begins to grow rapidly (began in Europe slowly after 1650, then more rapidly after the Industrial Revolution spread in the early 19th century).

Stage 3: Birthrates begin to drop rapidly, death rates continue to drop, but more slowly.  Economic and social gains, combined with lower infant mortality, reduce the desire for large families (in Europe, birthrates in some nations began to fall in the 19th century and spread across the region by the early 20th century).

Stage 4: Both birth and death rates are in balance, but at a much lower rate; population growth is minimal if at all (Europe since the 1970s).


The theory of demographic transition assumes that a country will move from a pre-industrial (agricultural) economic base to an urban, industrial one, with a corresponding decrease in family size and population growth.  The slowing of population growth theoretically results from better standards of living, improvements in health care, education (especially for women), sanitation, and other public services. Although this four-stage pattern has been repeated in other places besides Europe, there are local variations, sometimes significant, as the trajectory of development is everywhere different and by no means inexorable. For example, many of today's least-developed countries still retain the high birth rates characteristic of Stage 2. Also, parts of Europe, Russia and Japan may be entering a new, fifth stage, where birth rates are below death rates, and the population ages and begins to decline.


Pause and Reflect 2: 

Before continuing, think about the following questions and discuss them with your classmates:

1. The demographic transition theory assumes that birth and death rates begin to fall as nations develop their economies. Do you think economic development is enough to stabilize a country's population? Why or why not?

2. What has the demographic experience been in your country? Does it fit the demographic transition model? Why or why not?


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Resource-based Theories of Population


Human population growth does not occur at the same rate everywhere. In fact, some countries are experiencing population declines. Most European and North American countries, for example, have already experienced a substantial decline in fertility rates; they completed their demographic transition from high rates to low rates of fertility and mortality by the middle of the 20th century.  Many developing countries, in contrast, are now at an intermediate stage of low mortality as a result of improvements to public health, but still have high fertility rates; consequently, their population growth is rapid.


It is remarkable that, despite many new developments over the past 50 years, one fact looks very much the same: populations are growing most rapidly where such growth can be afforded the least — where pollution, resource shortages, and environmental damage create additional stresses on the ability of governments to meet the basic food, clothing, and shelter needs of their populations.


The relationship between human population growth and the availability of natural resources has occupied the minds of many thinkers since at least the 18th century.  However, it was Thomas Robert Malthus who for the first time gave a systematic analysis of population and resources, followed by Karl Marx, who had a radically different perspective than Malthus. These two theories will be discussed in the next several pages.



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Malthusian Theory of Population


Thomas Robert Malthus was the first economist to propose a systematic theory of population.  He articulated his views regarding population in his famous book, Essay on the Principle of Population (1798), for which he collected empirical data to support his thesis. Malthus had the second edition of his book published in 1803, in which he modified some of his views from the first edition, but essentially his original thesis did not change.


In Essay on the Principle of Population,Malthus proposes the principle that human populations grow exponentially (i.e., doubling with each cycle) while food production grows at an arithmetic rate (i.e. by the repeated addition of a uniform increment in each uniform interval of time). Thus, while food output was likely to increase in a series of twenty-five year intervals in the arithmetic progression 1, 2, 3, 4, 5, 6, 7, 8, 9, and so on, population was capable of increasing in the geometric progression 1, 2, 4, 8, 16, 32, 64, 128, 256, and so forth.  This scenario of arithmetic food growth with simultaneous geometric human population growth predicted a future when humans would have no resources to survive on.  To avoid such a catastrophe, Malthus urged controls on population growth. (See here for graphs depicting this relationship.)   


On the basis of a hypothetical world population of one billion in the early nineteenth century and an adequate means of subsistence at that time, Malthus suggested that there was a potential for a population increase to 256 billion within 200 years but that the means of subsistence were only capable of being increased enough for nine billion to be fed at the level prevailing at the beginning of the period. He therefore considered that the population increase should be kept down to the level at which it could be supported by the operation of various checks on population growth, which he categorized as "preventive" and "positive" checks.


The chief preventive check envisaged by Malthus was that of "moral restraint", which was seen as a deliberate decision by men to refrain "from pursuing the dictate of nature in an early attachment to one woman", i.e. to marry later in life than had been usual and only at a stage when fully capable of supporting a family. This, it was anticipated, would give rise to smaller families and probably to fewer families, but Malthus was strongly opposed to birth control within marriage and did not suggest that parents should try to restrict the number of children born to them after their marriage. Malthus was clearly aware that problems might arise from the postponement of marriage to a later date, such as an increase in the number of illegitimate births, but considered that these problems were likely to be less serious than those caused by a continuation of rapid population increase.


He saw positive checks to population growth as being any causes that contributed to the shortening of human lifespans. He included in this category poor living and working conditions which might give rise to low resistance to disease, as well as more obvious factors such as disease itself, war, and famine. Some of the conclusions that can be drawn from Malthus's ideas thus have obvious political connotations and this partly accounts for the interest in his writings and possibly also the misrepresentation of some of his ideas by authors such as Cobbett, the famous early English radical.  Some later writers modified his ideas, suggesting, for example, strong government action to ensure later marriages. Others did not accept the view that birth control should be forbidden after marriage, and one group in particular, called the Malthusian League, strongly argued the case for birth control, though this was contrary to the principles of conduct which Malthus himself advocated.


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Karl Marx's Theory of Population


Karl Marx (1818-1883) is regarded as the Father of Communism. He did not separately propose any theory of population, but his surplus population theory has been deduced from his theory of communism.  Marx opposed and criticized the Malthusian theory of population.


According to Marx, population increase must be interpreted in the context of the capitalistic economic system.  A capitalist gives to labor as wage a small share of labor's productivity, and the capitalist himself takes the lion's share.  The capitalist introduces more and more machinery and thus increases the surplus value of labor's productivity, which is pocketed by the capitalist.  The surplus is the difference between labor's productivity and the wage level.  A worker is paid less than the value of his productivity.  When machinery is introduced, unemployment increases and, consequently, a reserve army of labor is created.  Under these situations, the wage level goes down further, the poor parents cannot properly rear their children and a large part of the population becomes virtually surplus.  Poverty, hunger and other social ills are the result of socially unjust practices associated with capitalism.


Population growth, according to Marx, is therefore not related to the alleged ignorance or moral inferiority of the poor, but is a consequence of the capitalist economic system.  Marx points out that landlordism, unfavorable and high man-land ratio, uncertainty regarding land tenure system and the like are responsible for low food production in a country.  Only in places where the production of food is not adequate does population growth become a problem.


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Paul Ehrlich: Neo-Malthusian


As global populations rose spectacularly in the 20th century, theoretical debates over the extent and causes of the population problem expanded. Thomas Malthus and Karl Marx had set the initial stage for the world population debate, but other population theorists - including Paul Ehrlich, Julian Simon, Garrett Hardin, and Barry Commoner - would carry the ongoing discussion in the second half of the 20th century. 


In 1968, as world population hovered above 3 billion, Paul Ehrlich authored the book The Population Bomb, a widely read publication that sold several million copies in the United States alone.  Ehrlich, a biologist, maintained that the rate of population growth was outstripping agricultural growth and the capacity for renewal of Earth's resources. Given current rates of natural increase, Ehrlich predicted "certain" demographic disaster in response to eventual food shortages and disease.  In the opening to his book, he wrote: "The battle to feed all of humanity is over" and later stated that, "In the 1970s and 1980s hundreds of millions of people will starve to death in spite of any crash programs" (Ehrlich 1968).  Ehrlich argued that industrialized regions such North America and Europe would be required to undertake "mild" food rationing as starvation spread across the developing worlds of Asia, Latin America, and Africa. In a worst case scenario, he predicted that the lack of food security in the developing world would set into motion several geopolitical crises that could result in thermonuclear war. At its core, Ehrlich's population theory contained three major elements: a rapid rate of change, a limit of some sort, and delays in perceiving the limit.


While some criticized Ehrlich's work as simply a repetition of Malthus's 19th century argument, Ehrlich's most vocal opponent, economist Julian Simon, was skeptical of the more central tenets of the population bomb, particularly the definition of limits. In the 1970s, Julian Simon published two central pieces that served to galvanize the population debate: The Economics of Population Growth (1977) followed by The Ultimate Resource (1981). Simon argued that the relationship between population growth and economic growth was not as simple as Ehrlich believed, and that the extent to which population pressure impacted resources was overstated.  The crux of Simon's argument centered on his belief that Ehrlich's limit on the availability of resources was misdirected.  Simon instead argued that it was not possible to have too many people, for the only limit in determining the scarcity of resources was human imagination. People, the economist suggested, were the ultimate resource.  According to Simon, ingenious, resourceful humans had the capacity to invent crops with higher yields, or to construct inexpensive, safe housing for growing populations.  Simon's other contention was that current views on population and resource issues failed to take the long view, and that frequently too short a time frame was considered when examining demographic problems.



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The Simon-Ehrlich Wager


In 1980, Julian Simon and Paul Ehrlich engaged in a very public debate that underscored their disparate standpoints on population and resource scarcity. Known as the Simon-Ehrlich wager, Simon invited Ehrlich and his colleagues to select and purchase five non-government controlled resources worth a total of $1000 whose value would be measured over time. Agreeing to the wager, Ehrlich's team selected chromium, copper, nickel, tin and tungsten as the commodities and then chose 1990 as the payoff date. If the price of the resource bundle rose, this implied that the resource had become scarcer and Simon therefore would be forced to pay the difference. If the price of the bundle had dropped, this would signify greater abundance, and Simon would receive the monetary difference. 


Between 1980 and 1990, the world's population grew by more than 800 million, the largest increase in one decade, causing many to believe that the value of the bundle would rise due to population pressure and corresponding resource scarcity.  Yet in September 1990, the inflation adjusted price of all five metals had fallen, forcing Ehrlich to mail Simon a check for $576 to settle the wager. Wired Magazine eventually dubbed Simon a "doomslayer" for his stance against those who argued that an ecological Armageddon was around the corner. (For more discussion about the Simon-Ehrlich wager, see here.) 


In contrast, while Ehrlich was often criticized as a "doomsdayer" theorist, he is credited for developing a simple equation that examines population's relationship to environmental impact.  Known as the IPAT equation, Ehrlich argued that environmental impacts (I) are the result of three variables: population (P); affluence (A); and technology (T), as follows:

                                                I = P x A x T


Not surprisingly, Ehrlich implicated population size as the main driver behind environmental problems, disagreeing with environmentalists such as Barry Commoner, who believed inappropriate technologies and consumption to be the prime causes of degradation.  Nevertheless, in developing IPAT, Ehrlich put in place a new framework for population debates that looked beyond numbers to include human impact. Measuring the variables, however, can be challenging, particularly the technology variable.



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Garrett Hardin and Lifeboat Ethics


Ehrlich and Simon were not the only theorists of the 1970s to debate the extent and causes of the population problem, nor were they the last to discuss the merits of possible solutions. Biologist Garrett Hardin, known primarily for his research on common property resources, published "Life Boat Ethics" in 1974, a manuscript in which he outlined the case for and against aiding poor, populous nations.  Using a lifeboat as a metaphor for the position of rich, industrialized countries, Hardin questioned the ethics of whether "swimmers" surrounding the lifeboat should be taken aboard (or given aid) in light of the vessel's limited carrying capacity.


To explain the metaphor, Hardin pointed to proposals to create a World Food Bank, an international cache of food reserves to which "nations would contribute according to their abilities and from which they would draw according to their needs" (Hardin 1974).  Hardin questioned whether we should appeal to our humanitarian impulses and provide aid or whether we'd be better served caring for those individuals already positioned in the boat.


Hardin concluded that the World Food Bank is essentially a commons in disguise where the less "provident" will be able to "multiply" and tax the planet's resources at the expense of other nations that had planned for potential famine and disease through appropriate policies (Hardin 1974: 39).  Hardin argued that ultimately, this disparity would bring eventual ruin upon all those who share in the commons.  In the short run, Hardin concluded, a World Food Bank would diminish the need for food but in the long run would increase it without limit given rapid rates of population growth in developing nations. 


While some have criticized the lifeboat ethics stance as harsh or callous, Hardin actually supported those humanitarian projects that stressed technology and advice rather than those that supplied food or cash. In drafting his solutions to the population problem, Hardin invoked the Chinese Proverb: "Give a man a fish and he will eat for a day; teach him how to fish and he will eat for the rest of his days".  While Hardin criticized foreign aid that "frequently inspires mistrust rather than gratitude on the part of the recipient nation", he supported Rockefeller and Ford Foundation agricultural development projects that funded local, community-based solutions to poverty (Hardin 1974: 40).



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Barry Commoner and Poverty


In 1980, biologist Barry Commoner entered the population debate with his chapter entitled "Poverty Breeds Overpopulation". A strong critic of Hardin's lifeboat ethics, Commoner questioned how passengers in the lifeboat and swimmers in the ocean assumed their relative positions in the first place.  Tracing the roots of the problem to the colonial period, Commoner argues that initially, colonialism served to improve conditions and develop resources within colonies through the construction of roads, communication, and medical services. However, over time the resultant wealth in the developing world was siphoned away to developed nations in what Commoner calls a process of "demographic parasitism" (Commoner 1980: 4).  More simply, the gap between the rich and poor nations grew as the rich fed the poor with their own resources. Commoner suggests that this process of international exploitation had the added effect of rapid population growth in former colonies.  In other words, without financial resources available to improve living conditions, people in developing countries relied more heavily upon increased birth rates as a form of social security.  Commoner summarized: "The poor countries have high birthrates because they are extremely poor, and they are extremely poor because other countries are extremely rich" (Commoner 1980: 4). 


Commoner therefore concluded that the birth rate is not only affected by biological factors such as fertility and contraception but by social factors, such as quality of life.  If the standard of living continues to increase, Commoner argued, population rates eventually level off in a self-regulating process. Commoner's solution to the population problem was to increase GDP per capita as a way to motivate voluntary reduction of fertility.  He argued that the developed world has a duty to restore the imbalance in wealth between the developed and developing worlds by returning wealth to impoverished nations and abolishing poverty.


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Geographic Context: Ethiopian Famine and Live Aid


The 20th century population debate was made real when a drought of record proportions struck Ethiopia (primarily Tigray and northern Wollo) in 1984 and 1985, eventually impacting nearby Eritrea as well. The environmental damage wrought by drought was exacerbated by Ethiopia's civil war and the misallocation of government resources. Nearly 8 million people were affected by the drought, and over 1 million died as a result of starvation and disease. 


The international media's portrayal of the tragedy brought global condemnation to Ethiopia's handling of the crisis. Young children with distended bellies, victims of protein deficiencies such as Kwashiorkor, were captured in photographs and their illnesses portrayed on television. These images served to mobilize large-scale fundraising efforts for the east African famine. Most notably, in 1985, British musician Bob Geldof organized the musical relief effort, "Live Aid", encouraging Western nations to raise money and participate in relief efforts in East Africa. The Live Aid concert raised US$ 100 million, and was viewed globally, with 400 million people tuning in to see the program. 


Figure 4. News Report about Live Aid (1985)



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The Causes of Famine?


The Ethiopian crisis stimulated interesting questions about the demographic causes and consequences of the famine and how best to address the tragedy through policy. The tragedy enables students of geography to apply population theories to a particular place and time and to better understand the real world implications of policy recommendations.


Would the task of sending Western aid in the form of money and food to Ethiopia sink the lifeboat portrayed in Hardin's metaphor?  Or, following Barry Commoner's view, might Ethiopian relief efforts be more accurately viewed as "the return of resources" to a formerly wealthy nation made poor through colonialism? (Ethiopia, at the height of the Kingdom of Axum, boasted a mix of urban architecture, extensive trade networks, and mineral extraction, while in 1984 its GDP per capita was $283).


With a total fertility rate of 6.7 in 1984, the Ehrlich camp might identify Ethiopia's large population as the major culprit behind the crisis (US Census Bureau, International Database).  Left uncontrolled, population pressure ultimately increased stress on the nation's environmental resources; exacerbated by drought, these factors caused a crisis of Malthusian proportions.  Viewed from Julian Simon's standpoint, however, the Ethiopian people were not the problem but the solution.  What sorts of technologies might Ethiopians employ to increase crop yields and prevent future famines?   


In sum, the theories of Malthus, Marx, Ehrlich, Simon, Hardin and Commoner enable us to apply general demographic principles to real world geographic problems such as the Ethiopian famine. Yet the African famine cannot be separated from the particular economic, social, cultural and environmental context of that region. Indeed, there are differences in the world that call for consideration.  Not every location on earth is the same.  Because of geographic differences – whether in economies, population growth, or natural resource availability - we can see different outcomes resulting from population changes and resulting interactions with natural resources.  Geography therefore provides us with a lens for understanding the complex spatial dimensions of population issues.  


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Sustainable Development, Population, and Geographic Scale


In 1987, just a few years after the Ethiopian famine, the Brundtland Report was released by the United Nations.  Entitled "Our Common Future", the document lamented the degradation of environmental resources and outlined the effects that such deterioration would have on social and economic growth for world populations.


The Brundtland Report, named after the Commission's Chair, Gro Harlem Brundtland, then-Prime Minister of Norway, acknowledged that many environmental issues were global in scope and not necessarily limited to regions or locales:

"It is becoming increasingly clear that the sources and causes of pollution are far more diffuse, complex, and interrelated - and the effects of pollution more widespread, cumulative, and chronic - than hitherto believed. Pollution problems that were once local are now regional or even global in scale. Contamination of soils, ground-water, and people by agrochemicals is widening and chemical pollution has spread to every corner of the planet." (Bruntland 1987: Chapter 8: Resolution 18)


In recognition of the increased scale of resource problems, the document issued a call for sustainable development (Brundtland 1987: Chapter 2: Part IV).  Population pressure, food security, industry and energy – problems inherent to the developed or developing world - were all identified as equally critical challenges to sustainable development. In other words, Africa's rapid population growth rates caused concern for the environment, but so, too, did the demands of energy hungry nations in the West. In conclusion, the Commission argued that regional, national and international institutions and non-governmental organizations had the capacity to create policies at various scales that would affect environmental change worldwide.


Indeed, the importance of acknowledging the concept of geographic scale in understanding population and resource issues had become apparent in the Bruntland Report. Local and global scales have inevitably become linked in this age of globalization. Sustainable development policies, if they are to be effective, need to recognize these important spatial connections. Poverty in southern Africa may drive people to have more children (local scale), but economic markets (global scale) that make African nations dependent upon single commodity exports exacerbate poverty. Geographers such as Bernard Nietschmann (1997) and his research, based mainly in Nicaragua, have long recognized the important role that geographic scale plays in interpreting population and resource problems.


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In this conceptual framework, you learned how population change could be measured using geographic tools and data.  You also considered different theories held by scientists (Malthus, Marx, Ehrlich, Simon, Hardin and Commoner) about the causes of population growth and its effects on the Earth's environment using the Ethiopian famine to provide geographic context.


Although food production in different world regions has generally increased at similar rates, there has been much more variability in the rate of population growth from place to place.  In countries where populations are growing rapidly, there is some concern that this growth threatens the local availability of resources.  Indeed, some scientists warn that the Earth has a carrying capacity that limits the number of people that the environment can support.  But not all scientists share this view.  Whereas some point out that the environmental "doomsday" scenarios that were predicted many decades ago have failed to materialize, others believe the world's poor are the victims of a global economy that distributes power and resources unequally.


In the case studies for this module, you will learn more about the economic, political, and environmental dimensions of population growth and its impact on natural resources in different countries. You will see how important it is to understand the specific local contexts of these relationships. For a preview of the case studies, continue to the next page.


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Case Studies


The Population and Natural Resources module currently offers four geographical case studies built on the ideas and theories presented in this conceptual framework. They provide examples of environmental, political, and social issues related to population change and economic development. 


1. Case study: How can food be produced sustainably to feed growing populations? Focusing on Argentina, this case study examines how increases in soybean production have resulted in varied environmental and social impacts.


2. Case study: How does urban development affect the quality and quantity of natural resources? This case study examines the impact of urban growth on the availability of agricultural land in the United States.


3. Case study: What are the challenges of meeting the resource needs of very large populations? In this case study, set in China, you will analyze the challenges posed by a large population for ensuring safe and adequate access to water resources. 


4. Case study: Was population growth responsible for rapid deforestation in the Central Highlands of Vietnam? In the Vietnam case study, the causes and consequences of the conversion of forests to coffee plantations is analyzed.


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Commoner, B. 1980.  Poverty breeds overpopulation, in I. Vogeler and A. DeSouza (eds.): Dialectics of Development, Rowman and Allanheld.

de Mesa, J., T. Gisbert, and C. D. Mesa Gisbert. 1999. Historia de Bolivia. La Paz, Bolivia: Editorial Gisbert y CIA S.A.

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Ehrlich, P. 1968. The Population Bomb. New York: Ballantine.

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Hardin, G. 1968. The tragedy of the commons. Science 162: 1243-1248.

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Nietschmann, B. 1997. Protecting Indigenous Coral Reefs and Sea Territories, Miskito Coast, RAAN, Nicaragua, in Conservation Through Cultural Survival: Indigenous Peoples and Protected Areas, Stanley F. Stevens, ed., Island Press, Washington, D.C., pp. 193-224.

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_____. 1981. The Ultimate Resource. Princeton: Princeton University Press.

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US Census Bureau. 2008. World Midyear Population, 1950-2050.


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