The population explosion: why we should care and what we should do about it.

Almost everyone has heard about the population explosion, but few people understand its significance. Following is a brief overview of the basic problem caused by the rapid increase in human numbers from roughly one billion people in 1800 to some, six times that number less than two centuries later. Half of that growth has occurred just since 1960, and it appears that, at a minimum, two to three billion more people--and possibly several billion beyond that--will be added to the population before growth ends (assuming a disastrous die-off can be averted). The significance of numbers in the billions is often difficult to grasp; suffice it to say the world is annually adding roughly the population equivalent of present day Germany, and that perhaps thirty to fifty more `Germanys' are likely to be added to the population before reduced birth rates can bring growth to a halt.

I. WHY IS THE POPULATION EXPLOSION IMPORTANT?

If one asks this question of an acquaintance, the answer often focuses on crowding. A resident of the San Francisco Bay area might mention the perpetual traffic jams on the freeways. Or there might be some comment about starvation in Africa, or the flow of refugees into California from Mexico and the resultant strain on school and health budgets. While there is a population component in those problems, such answers do not get to the most important consequences of overpopulation. Moreover, debates about the roles of women in society, and particularly battles over whether women should be required by the government to carry fetuses to term, have given many Americans the misimpression that population problems should be viewed mainly as issues of the reproductive rights of individuals. In the extreme, this narrow focus has led the uninitiated to claim that there is no connection between the size of the human population and environmental problems.(1) All these views miss the main point.

A. Population Impact on Life-Support Systems

The overriding reason to care about the population explosion is its contribution to the expanding scale of the human enterprise and thus to humanity's impact on the environmental systems that support civilization. The number of people (P), multiplied by per capita affluence (A) or consumption, in turn multiplied by an index of the environmental damage caused by the technologies employed to service the consumption (T), gives a measure of the environmental impact (I) of a society. This is the basic I = P x A x T identity, often just called the "I = PAT equation."(2) A useful surrogate for the A x T of the I = PAT equation is per capita energy consumption ([E.sub.pc]); hence I = P x [E.sub.pc].(3) Almost all of a society's most environmentally damaging activities involve the mobilization and use of energy at high levels, including the manufacture and powering of vehicles, machinery, and appliances; constructing and maintaining infrastructure; lighting and heating buildings; converting forests into paper, furniture, and homes; producing inputs for, and processing and distributing outputs from, high-yield agriculture; and so on.

The surrogate formula has some drawbacks, however. At the lowest levels of development, energy use probably underestimates environmental impact. For example, very poor people can cause serious environmental damage by cutting down trees for fuelwood. At the highest development levels, energy use probably overestimates environmental impact: a given amount of energy use in Western Europe, Japan, or the United States undoubtedly provides more benefits and does less damage than the same amount used in Poland or Russia because of much greater efficiency and stricter environmental regulation. Yet, despite these imperfections, for comparisons between nations or for intertemporal comparisons, energy use seems to be a priori a reasonable measure that correlates with many types of environmental damage. It certainly is the most readily available statistic with those characteristics.

Employing energy use as the standard, the scale of the human enterprise has grown about twenty-fold since 1850.(4) During that time, per capita energy consumption has risen about five-fold globally,(5) and the population has grown about four-fold.(6) Roughly then, population growth can be considered to be responsible for about 45% of humanity's environmental peril: the combined risks accrued as a result of increasing worldwide environmental impacts.(7) The risks arise from human-caused worldwide changes such as widespread habitat destruction (e.g., deforestation, desertification, urban construction), alteration of the composition and geochemical processes of the atmosphere (e.g. the addition of excess greenhouse gases, depletion of stratospheric ozone, generation of air pollution), overdrafts of groundwater, soil depletion and erosion, water pollution, disruption of the hydrologic, carbon, and nitrogen cycles (among others), and general toxification of the planet. These and many other factors combine into an unprecedented assault on the life-support systems of civilization: the global cycles and natural ecosystems that supply indispensable goods and services to humanity.(8)

These mostly unappreciated but indispensable benefits include the maintenance of the quality of the atmosphere, regulation of the climate, provision of food from the sea, replenishment of soils, control of pests, and other vital underpinnings of agriculture, production of timber, medicines, and myriad other industrial materials, and regulation of freshwater flows (including controlling floods and droughts) and other forms of weather amelioration.(9) Natural ecosystems also maintain a vast genetic library from which humanity has already derived all manner of things, including domesticated plants and animals, and which is essential to their continued usefulness.(10)

The I = PAT equation carries an especially important lesson for Americans. It is customary to think of poor nations as overpopulated compared to rich ones, but in terms of global environmental impact, exactly the opposite is true. It is true that most European nations and Japan have greatly slowed, halted, or even reversed their population growth, while most developing nations continue to expand their population sizes at rates of 1.5% to 3.5% per annum.(11)

But when consumption, the A x T factor ([E.sub.pc]), is considered, an entirely different picture emerges. Thus, around 1990, the average American used some 11,100 watts (11.1 kilowatts, kW)(12) per person, more than ten times as much energy as the average citizen of a developing country.(13) In actuality, the gap between the United States and developing nations is often much wider. For example, the United States in 1990 used 195 times as much commercial energy per capita as Madagascar, 20 times that of Zambia, and 13 times that of China.(14) In other cases, it was narrower: eight times that of Malaysia and six times that of Mexico.(15) Using commercial energy as a measure excludes the use of gathered wood, crop residues, and animal wastes as fuel by poor farmers, so the actual per capita energy consumption in very poor countries is somewhat understated. And in some developing nations such as China, Indonesia, and Malaysia, commercial energy use is growing very rapidly.(16) Nevertheless, the overall picture is quite clear.

The United States already has the world's third largest population, 268 million people. China is number one with 1.24 billion, India number two with 970 million, and Indonesia number four with 205 million.(17) Compared to other industrialized countries, the American population is growing at a record rate of more than one percent per year (if immigration is included). When the population figures are added to energy consumption it is easy to see why the United States can be called the most overpopulated nation.(18)

By assaulting earth's ecosystems, humanity is, in essence, sawing off the limb on which it perches. Population growth is clearly a major force behind the saw. The chances of successfully feeding and otherwise caring for an expanding population are being continuously diminished. That is why all human beings should care deeply about the population explosion and, because of their own disproportionate environmental impacts, why Americans should show particular concern.

II. WHAT SHOULD BE DONE ABOUT THE POPULATION EXPLOSION?

It is a great deal easier to explain why the population explosion should be a critical issue for all of humanity than it is to find one's way through the manifold issues of what ought to be done about it.

A. Basic Goals

The easiest answer to the question above is move as rapidly as is humanely possible toward an optimum sustainable population size. But this vague answer immediately raises a series of obvious questions: What is an optimum sustainable population size? What steps would move society in that direction? How does one establish what is humane? Science can put theoretical bounds on the answer to the first question, since there is a biophysical upper limit on the number of people that could be supported over the long term with a given set of technologies and social (including political and economic) arrangements.

But most people would probably agree that there is a considerable difference between the largest sustainable population and an optimal sustainable population. Few would find supporting the maximum number of human beings, in a situation somewhat analogous to the way battery chickens are reared, to be optimal. Many would desire varied diets, comfortable homes, opportunities for travel and solitude, uncrowded living conditions, and other amenities, all of which would reduce the number of people that could be sustained. With an approximation of current conditions, it has been estimated that the upper bound of an optimum population, one that would in some sense allow for a maximum quality rather than quantity of human life over the long term, would be in the vicinity of two billion people, about one third the current number.(19)

That estimate is based largely on patterns of energy use. Today, humanity is using roughly 13,000,000,000,000 watts of energy.(20) In more convenient notation, that is 13 x [10.sup.12] watts, or 13 terawatts (tW). With that much energy use, humanity has developed a quite unsustainable civilization. Indeed, it is only able to maintain some 5.8 billion people today, with a billion or so undernourished and in desperate poverty, by using up its natural capital.(21)

The most important forms of natural capital are productive agricultural soils, fossil groundwater, and biodiversity. Soils, which normally are generated on a scale of inches per millennium, are in many places being eroded at rates of inches per decade. At least twenty-five billion tons of topsoil are lost annually,(22) and some estimates range far higher.(23) In many areas, groundwater that accumulated during the ice ages is overdrawn. In the southern high plains of the United States, the Ogallala aquifer is naturally recharged at a rate of about one-half inch per year, but is being pumped at a rate of four to six feet per year to irrigate crop fields.(24) This "mining" of the aquifer produces a net withdrawal about equal to the flow of the Colorado River.(25) Similar overdrafts of groundwater are occurring in many areas of the world, including parts of India and China.(26) Depletion and degradation of natural resources is, of course, a story as old as civilization;(27) what is new is the unprecedentedly colossal and planet-wide scale on which it is occurring today.

The loss of populations, species, and communities of plants, animals, and microorganisms that are working parts of our life-support systems (and thus partly responsible for the delivery of ecosystem services(28) is the most irreversible loss of all. Just one element of biodiversity, species diversity, is disappearing at a rate estimated to be 1000 to 10,000 times the "background" rate, which is the more or less constant extinction rate that biologists presume to occur naturally over time.(29) Populations, another critical element, are disappearing even faster. We are witnessing the greatest biological cataclysm of the last sixty-five million years--since an apparent collision with an extraterrestrial object exterminated the dinosaurs and much of the rest of Earth's flora and fauna.(30)

In short, in a 13 tW world, humanity is unable to maintain itself on its natural "income," the sustainable flow of solar energy and cycles of elements in the biosphere. Like a profligate son, humanity is spending its inheritance of capital, in essence bragging each year that it is writing bigger and bigger checks on its "account" while paying no heed to the plum meting "balance." This behavior is supported by diverse claims that fly in the face of all of environmental science:(31) technology can save humanity because resources are infinite,(32) population growth can continue for another seven billion years,(33) and there is no need to worry about the state of the environment.(34)

All the degradation and depletion of natural resources that should be constantly renewed through solar energy and ecosystem functions, as well as the generation of various forms of pollution and the buildup of greenhouse gases in the atmosphere leading to global climate change, are largely being driven by civilization's use of 13 tW of non-solar energy, mostly from fossil fuels. Thus, it would seem that a 4.5 to 6 tW world, given substantial changes in human behavior, might be sustainable while providing everyone in a moderately large population with a life of reasonably high quality.(35) But will it be possible to get there without wrecking our life-support systems? Since it seems nearly inevitable that the human population will not stop expanding until it has reached at least eight to ten billion people several decades from now,(36) it is clear that one or two additional centuries would be required for a gradual, humane reduction to an optimum population size, assuming that some way is found to support the gigantic overshoot of carrying capacity.(37) Energy expert John P. Holdren of the Kennedy School at Harvard University has shown a way that a successful transition to a sustainable pattern of energy use might be achieved.(38) But the Holdren scenario is based on what seem today to be extremely optimistic assumptions.(39) It envisions at least a temporary increase to a 27 tW world--a frightening prospect to those of us watching the trends in a 13 tW world. In the latest version of the Holdren scenario,(40) developing nations would develop fast enough to increase their per capita energy use by about 2 percent per year between 1990 and 2040, raising it from 1.0 to 2.5 kilowatts (kW). Simultaneously, the industrialized nations would strive to reduce their per capita use through increased efficiency, dropping their energy use per person from 7.5 to 4.1 kW, while maintaining or enhancing the quality of life. Rich and poor nations would converge on an average per-person energy use of 3 kW during the remainder of the 21st century. Since energy use is a reasonable surrogate for estimating availability of the various physical ingredients of human well-being, the Holdren scenario represents an elimination of international inequity. In our view, that is a key requirement for creating conditions in which any significant amount of biodiversity can be maintained. Meanwhile, in the scenario, the world population peak size of nine billion people would be passed by 2100--a reasonably achievable goal--then a slow decline would begin. During the peak period, total energy use thus would be 9 billion x 3 kW, or 27 tW. Holdren's scenario is summarized in the following table:(41)

TABLE 1. THE HOLDREN SCENARIO

POPULATION x ENERGY/PERSON = TOTAL ENERGY USE
             [billions]  [kilowatts = kW] [terawatts = TW]

1990 RICH       1.2             7.5              9.0
   POOR         4.1             1.0              4.1
                5.3                             13.1
2040 RICH       1.3             4.1              5.4
   POOR         7.5             2.5             19.0
                8.8                             24.4
2100             9               3               27

Remember that this version of Holdren's scenario assumes that the total human population size can be contained at approximately nine billion.(42) The scenario also assumes that a high standard of living can be achieved with a per capita rate of energy use of only one fourth to one third of that now seen in the United States.(43) This assumption seems plausible, based on technologies already in existence. But it might entail redevelopment of the United States into a lifestyle and infrastructure centered around people rather than automobiles, so that virtually everyone could walk or bicycle to their workplaces or work at home using advanced communications systems.

Such a change might seem disastrous to those who think gross national product must grow no matter what, but the change could be highly beneficial for the quality of life. Indeed, depending on assumptions made about major energy sources and end uses in the future--which sources and technologies supply what fraction of energy and for what use--efficiency alone could make available the equivalent of 10 to 40 tW by the year 2050.(44) Holdren's scenario depends on increased efficiency supplying the services of some 40 tW in today's technologies by 2100--the difference between the scenario's 27 tW and the 67.5 tW that would be required to give nine billion people a lifestyle resembling that of Europe or North America in the 1990s, powered by 1990 technologies using 7.5 kW per capita.

Even with such enormous gains in efficiency, it must be emphasized that Holdren's scenario still yields a total energy use more than twice that of 1990, a situation that would produce horrendous environmental impacts unless the mix of energy sources and technologies were substantially different from today's. Fortunately, policy analysts already widely recognize that the mix must be changed (although this has not been generally recognized by decision makers).(45) The main thrusts behind this recognition are the clear limits to readily accessible supplies of petroleum and natural gas, and increasing public opposition to unacceptable environmental risks and tradeoffs such as oil spills in fragile coastal or polar areas or the sacrifice of prime farmland to strip-mine coal. Needless to say, such a shift will be essential if biodiversity is not to suffer catastrophic losses, leaving surviving restoration ecologists struggling to stabilize a weedy world with crippled ecosystem services.

Of course, there clearly is a lower bound on an optimum population size, depending especially on the nature of the technological infrastructure envisioned. A global population of, say, ten million people, distributed geographically more or less in proportion to today's population, would not be able to maintain a technological civilization resembling today's, whereas a population of one billion clearly could. Needless to say, there is not the slightest reason to be concerned about too small a population or risks from population shrinkage today, although one can find fears of having too few children voiced in such places as the editorial pages of the Wall Street Journal,(46) despite analyses that show them to be erroneous and fruitless.(47)

B. Control of Conception

The key to any humane management of human population size is regulation of birth rates. The objective is to avoid a death-rate solution to the population outbreak in which billions of people perish prematurely and in misery. This means that people must have both the knowledge and means to control their reproduction. Human beings have exercised some control over their reproduction for at least thousands and perhaps hundreds of thousands of years.(48) The techniques employed have ranged from crocodile dung suppositories in ancient Egypt(49) to infanticide from hunter-gatherer times up to 1979 in China,(50) and have varied in both their efficacy and social acceptability just as modern techniques do. In the 20th century, the story of birth control in the now-industrialized nations has been one of gradual acceptance of modern forms of contraception, strongly associated with the movement for women's liberation and an assertion of women's rights to determine the number and timing of children they bear.(51)

In the United States and Western Europe, cultural and religious-based biases against contraception are no longer taken seriously by the majority of people.(52) For example, despite the Catholic Church's prohibitions against contraception and abortion, the average completed family sizes in Catholic Italy and Spain are among the smallest in the world (1.2 children in 1997),(53) and both contraception and abortion are widely used in the United States, a country with a substantial Catholic population. In the United States, Catholic women have slightly smaller families than Protestant women.(54)

It is therefore curious that, just as the use of modern methods of birth control is gaining ground rapidly in the developing world,(55) some feminists and conservatives are taking the position that family planning programs are repressively pushing unwanted birth control on women. While reproductive rights are obviously an important element of any discussion about policies to deal with the population explosion, curtailment of those rights is only one possible consequence of population policies. Yet such repression has been seen in a relatively few instances, notably in China from local enforcement of the one-child family policy.(56) In the mid-1970s, the Indian government tried to enforce a three-child limit for government employees, for which Indira Gandhi lost her seat as prime minister.(57) More recently, there have been accusations of poor Brazilian women being sterilized without informed consent(58) and reports of undue pressure in Indonesia.

Nevertheless, restriction of the right of individuals to limit their reproduction because of a lack of information or the means to do so, is still far more common. Even when access to birth control is available, many programs fail to offer a full selection of methods to clients, which in effect can also restrict their rights. In Pakistan, for instance, the family planning program has relied almost entirely on intra-uterine devices (IUDs),(59) which are not suitable for all women at all stages of their reproductive lives.(60)

In the area of birth control technology, there still is a pressing need to develop and disseminate a variety of simple, inexpensive, and effective techniques. Improved design and distribution of condoms is especially important because of the role of condoms in reducing the transmission of sexually transmitted diseases (STDs), especially acquired immuno-deficiency syndrome (AIDS). Production and distribution of RU-486 and other abortifacient compounds, which do not require a surgical procedure and can be used in privacy, also should be given high priority. The goal is a human population in which every sexually active individual has the information and a wide choice of methods to control his or her fertility.

C. Family Size Preferences

Providing the means to control fertility can help reduce birth rates, since there is still a very large unmet demand for contraception.(61) Increasing accessibility of birth control will do little good, however, unless people choose to limit their family sizes to an average level that eventually will produce zero population growth and then declining populations worldwide. Ideally, completed family sizes everywhere should be reduced to an average in the vicinity of 1.5 children for several generations. Globally, the average today is three.(62) Total fertility rates (TFRs), in essence average family sizes, are much higher in many poor countries: Nigeria has an average of 6.2, Iraq, 5.7, Pakistan, 5.6, and Honduras, 5.2. India's TFR has fallen to 3.5. Yet some countries that have low incomes are doing considerably better: Indonesia's TFR has fallen to 2.9, Costa Rica's to 2.8, Brazil's to 2.5, Thailand's to 1.9, and China's to 1.8. Rates are generally lower in high income countries, with France at 1.7, Japan at 1.5, Germany at 1.3, and Italy at 1.2. The United States remains an outlier among the rich, with a TFR of 2.0.63

Many factors appear to influence family size preferences. One is the stage of development of a nation. In the West, both birth and death rates were high in the eighteenth century. As the industrial revolution spread, accompanied by rapid urbanization, rising education rates, and improved public health conditions, first death rates and then birth rates slowly declined.(64)

In non-industrialized nations after World War II, the deployment of very efficacious "death control" technologies, especially antibiotics and the use of diclorodiphenyltrichloroethane (DDT) against mosquitoes that transmit malaria, led to precipitous drops in death rates. Most of the factors that lead to lower birth rates were not present, however, and the result was the post-war population explosion in non-industrial countries. In some regions, fertility remained very high for several decades after death rates had fallen to levels below those that had preceded falling birth rates in more developed societies.(65) Conversely, in other nations, fertility began to fall before much progress had been made in industrializing or raising income levels.(66)

D. Development Economics

This apparently contradictory situation left demographers and economists scratching their heads; if "development" was supposed to be the magic bullet that reduced fertility, why did some underdeveloped societies have falling birth rates, while others, seemingly more advanced, still have high ones? Eventually, it was learned that some important key factors, besides the obvious one of lower infant and child mortalities, are involved in motivating couples to have fewer children. The education of women, and their ability to participate outside of the home, in society, appear to be especially important.(67) Some studies show that when women are educated and economically active, not only do birth rates fall, but their societies benefit broadly and develop more rapidly.(68) The perceived value of children to their parents is also important. When young children contribute to their family's income as farm and household help or in commercial activity, rather than requiring financial support while in school, parents are motivated to have more of them.(69)

E. Equity Issues

An important element in both successful development and in curbing fertility is increased equity between the sexes.(70) Even a few years of schooling enables women to do a much better job of caring for their families; they can choose more nutritious food, practice basic sanitation, seek medical help when needed, and augment family income. Such seemingly modest changes increase a society's general well-being and boost economic development. Indeed, no society that has kept the majority of its women illiterate and dependent has attained full modernization.

Similarly, equity among social groups within society, especially between rural and urban groups, is a critical factor in successful development. Too many developing nations (unlike their models in the industrialized world) have neglected their agricultural sectors while concentrating on manufacturing and urban development. The result often is the development of a two-tiered society, divided between very rich and very poor segments sandwiching a tiny, struggling middle class. The rural poor, with high birth rates and little support from government or private sector interests, soon expand beyond the capacity of their meager re sources. Millions, squeezed off the land, flock into cities seeking jobs, of which too few exist.(71)

Another common pattern is for men to migrate to cities seeking supplementary jobs, leaving wives and children to operate the family farm.(72) The women, however, have no power to obtain credit or other outside support such as irrigation or farm inputs. The result is land degradation, desertification, and deepening poverty. Food production lags, especially when the best land and agricultural resources are channeled into cash crops for export. In such situations, birth rates generally remain high, as do infant and child mortality rates, and chronic hunger may be widespread.(73)

In sharp contrast to this dismal picture is the success of the "Asian tigers"(74) and some other developing nations. Among their early priorities were strong farm sectors, universal education, basic health and sanitation services, and family planning programs.(75) These societies generally do not have enormous income disparities, and they do have growing middle classes, low birth rates, high life expectancies, adequate food supplies, and diversified economies. They also, however, have burgeoning environmental problems, and too many of them are increasing their prosperity by consuming or degrading natural resources such as forests, agricultural land, and fisheries in an unsustainable fashion.(76)

Finally, equity among nations will be essential in finding answers to the human dilemma. Today's developing nations are emerging from a history of colonization by European nations, followed by several decades of "economic colonization" by the West, in which they were kept at a disadvantage in trade and development opportunities. In recent decades, less developed nations have been involved in world trade as commodity producers, and prices of commodities have steadily fallen in relation to prices of finished goods, which they need to import. Thus, their participation in the world trade system has generally done little or nothing to increase their prosperity, and the income gap between rich and poor nations has continued to widen.(77)

This situation has not operated to foster trust or a cooperative attitude among leaders of developing nations toward the industrialized, over-consuming minority. Thus, proposals by rich nations to support family planning programs in developing countries, or pressure to cooperate in eliminating use of chlorofluorocarbons (CFCs), preserving tropical forests, or curbing carbon dioxide emissions (especially when the rich take little action on these matters), are understandably met with suspicion and demands for financial assistance. Until and unless the world's rich and poor nations begin a trend toward convergence in wealth and incomes and a more sustainable economic system for all societies, the cooperation among nations so vitally needed to manage the human predicament will be difficult, if not impossible, to achieve.

F. Barriers to Controlling Population Growth

Religious beliefs and traditions have often presented barriers to efforts to reduce population growth. The Vatican, in particular, has maintained political opposition to family planning programs and is adamantly opposed to abortion.(78) Still, family planning programs now exist in virtually every nation and have been at least tacitly accepted--and sometimes even supported-by local church authorities. Furthermore, the reproductive behavior of Catholics is usually similar to that of people of other religions in the same societies.(79) Nevertheless, Papal opposition is officially maintained, hindering support for programs in developing nations and lessening the chances for establishing effective population policies in the United States. The latter is especially pernicious, not only because of the environmental damage done by a vast overpopulation of American super-consumers,(80) but because U.S. policies (or the lack thereof) are widely emulated.

Other major religions do not present political barriers to population control policies. However, the traditions associated with them, such as the low status of women in many Islamic societies, can retard the acceptance of family planning and smaller families.(81) Traditions that emphasize male dominance, such as "machismo" in Latin America and analogous attitudes in much of Africa, have similar effects, independent of religion. In such situations, administrators of family planning programs have learned that husbands (and sometimes their mothers) need to be involved when smaller families are advocated.

III. WHAT NEEDS TO BE DONE

The cultural norms for family size in any society can be modified under appropriate circumstances. Indeed, only a handful of countries still have pre-industrial birth rates of six or more children per family. Those countries are generally characterized by extreme poverty. Typically, they lack basic amenities such as safe drinking water, adequate food, health care, and education. Thus, the prerequisites for success in ending population growth, remarkably akin to those required for successful modernization, are the following: basic health care and sanitation, education and economic opportunities for both sexes, local control over supporting resources, and fair and responsible government.

There are some societies where the basic amenities, including education for women, are provided and the birth rate still remains high. Typically, these are societies hindered by a powerful tradition of male dominance and female dependence. Often the family planning programs are weak or nonexistent.(82) The provision of family planning information and services is important for enabling people to implement their family size decisions, backed up by safe abortion services where the culture permits.

These basic requirements have for decades been reasonably well fulfilled in most of the industrialized world, and birth rates accordingly are almost uniformly low, or in some cases well below replacement. Many other nations have recently reached or passed transitional stages of development during which these prerequisites were largely met, and they too have fertility rates at or near replacement. However, since their fertility has only recently fallen, a good deal of momentum remains in the population structure, and substantial population growth will still occur. Thus, demographers project that China, which reduced its total fertility rate (TFR) from nearly 5.0 in 1970 to about 2.3 by 1980, will grow from today's 1.2 billion to about 1.6 billion before growth stops.(83) Enormous momentum, of course, remains in the developing nations that still have high birth rates; they may more than double their present population sizes before growth ends.

Projections for sub-Saharan Africa, for example, indicate that the region's population of about 600 million in 1997 will more than double by 2025 and continue growing for decades thereafter.(84) Even though some African nations recently have begun to show declines in birth rates, the average family size for the region is still six.(85) Persisting poverty, inadequate food supplies, poor health standards, and high illiteracy rates are typical of the region, which also has a strong tradition of male dominance.(86) Reversing the downward spiral of poverty and hunger in subSaharan Africa will require a huge effort to modernize economies, including the agricultural sectors, reverse the degradation of the natural resource base, improve health and reduce infant and child mortality rates, educate millions of people and develop employment opportunities for them, reform corrupt and brutal governments, and promote family planning. Accomplishing all this in the face of continuing rapid population growth and the spread of AIDS and other serious diseases will be no easy task.

Family planning programs succeed best when supported by government policies that promote smaller families. Political leadership in many societies has been shown to have potent effects; enlistment of support from religious leaders and institutions also can be helpful. For example, when Mexico launched its Responsible Parenthood program in the late 1960s, public support of most of the country's bishops was a critical element in its rapid acceptance by Mexicans. In those African nations where family planning is at last being accepted by increasing numbers of women, public support from government leaders has also been an important factor.

A. Population Policies in the United States

Since the United States is, in important respects, the world's most overpopulated nation,(87) and the most rapidly growing industrial nation,(88) it behooves us to ask whether and how the legal system might aid in controlling our population size. Unlike many developing nations, the United States has no explicit population policy. It does, however, have a number of implicit policies, including income tax deductions and free public education for each child, which are mildly pro-natalist in effect. The recent legislation to give families a $500 tax credit for each child adds a further incentive to reproduce.(89) Nonetheless, family planning information and materials are widely available and even subsidized for low income people. Abortion is legal, although increasingly surrounded with restrictions,(90) potentially due to pressure from conservative religious groups.

It was not always easy to obtain contraceptives in the United States. The Supreme Court struck down the last of the "little Comstock" state laws forbidding dissemination of birth control information in 1965,(91) and legalized abortion in 1973.(92) However, the battle to win the right to control one's reproduction by a choice of methods is far from over. Although American drug companies in the past were leaders in the development of new contraceptive methods, many materials and devices have failed to reach the U.S. market or have been withdrawn as a result of lawsuits or fears of liability.(93) Others have been delayed by many years.(94) Today, companies in the United States have largely abandoned the field of contraceptive research, and as a result, the choice of contraceptive methods available to Americans is narrower than it was in 1980.

Meanwhile, abortion rights have been chipped away by various restrictions applied by Congress and the states. These restrictions include requiring women to sign informed consent forms, forbidding public employees to perform abortions, requiring physicians to inform patients of possible emotional complications, requiring consent of partners or parents of underage teenagers, and requiring a forty-eight hour waiting period.(95) All of these add to the difficulties of obtaining an abortion, and in many cases (such as the parental consent requirement) may erect impassable obstacles. At the same time, continuous protests and harassment of patients and medical personnel at abortion clinics by abortion opponents have forced many facilities to shut down, thus reducing the availability of services.(96)

In its foreign policies, the United States has long encouraged family planning efforts. Even before access to contraceptives was fully available to Americans, the Foreign Assistance Act of 1961 granted the authority to the President to create policies on population planning.(97) Support for family planning assistance as a part of foreign aid for developing nations was offered soon after that, and throughout the 1960s and 1970s, the United States was a major supporter of demographic research and family planning programs. The United States provided support mainly in the following three ways: 1) funding for the United Nations Population Fund (UNFPA), 2) funding for International Planned Parenthood Federation (IPPF, a private organization), and 3) bilateral aid given directly to recipient nations through the United States Agency for International Development. The same year that abortion was legalized in the United States,(98) the use of government funds to support legal abortion services in other countries was banned.(99)

After Ronald Reagan became president in 1981, funds for family planning assistance were severely cut back and ultimately eliminated for UNFPA and IPPF on the pretext that these organizations were funding abortion counseling, referral, or services. In actuality, however, United States funds were being carefully kept separate from such activities in accordance with an earlier requirement. This became known as the "Mexico City policy" after it was announced at the second U.N. Conference on Population held in Mexico City in 1984.(100) The Administration's position was that population growth was not a problem, and that position was maintained by the Bush administration. Not until President Clinton took office in 1993 were the Mexico City policy reversed and funds released for overseas family planning programs. Yet, despite full support from the Clinton administration, the appropriation of funds for family planning assistance has turned into an annual battle in Congress, especially since the Republicans, dominated by religious conservatives, won control of both houses in 1994. Nonetheless, even though the governments of developing nations have increasingly assumed the financial burdens of their family planning programs, assistance from the United States and other wealthy countries is needed to build stronger and more humane programs along the lines advocated at the 1994 U.N. Population and Development Conference in Cairo.(101)

As for the domestic population policies of the United States, there clearly is much room for improvement. One of the first things the nation should do is devise a policy that encourages, rather than discourages, drug companies to research, test, and market promising new contraceptive materials. In addition, the nation should subsidize effective birth control methods for the poor and make them widely available. Public schools should provide education on sex, reproduction, and parental responsibility. Further, the right of access to safe, legal abortion needs to be upheld.

Beyond ensuring the availability of family planning services to the public, the United States government could do more to develop policies that will put an end to population growth and eventually lead to a decline in population to a more sustainable size. A simple declaration by the Administration, perhaps backed by a well-publicized commission report, that further population growth is undesirable for the future well being of Americans, might carry considerable weight. That was the conclusion of a government commission report on "Population and the American Future" in 1972.(102) Reaffirming that prior commissions' findings could have substantial influence not only domestically, but abroad, because people in other countries are very aware of the consumption burden that Americans place on the entire world. Such policies would be among the mildest possible changes--certainly representing no threat to an individual's right to choose his or her family size--yet they might have a significant effect in lowering the U.S. birth rate.

A few steps beyond those mentioned above, but still far from repression, nevertheless, are entirely possible within American traditions of individual liberty. In passing, we might point out that increased population growth and the resultant crowding, urban congestion, and conflicting demands on limited resources such as land and water are considerably greater eroders of personal liberty.(103) Sex and family education programs, as well as family planning programs, could include strong messages to discourage early sexual activity, unplanned childbearing, and single motherhood. Indeed, such messages are already being promoted by conservatives as part of their "family values" campaigns and are embodied in recent legislation curtailing benefits provided by welfare programs. Welfare time limits and bans on benefits for children conceived on welfare are relatively Draconian, yet they have been enacted.(104) No doubt they will depress the birth rate among welfare recipients.

Tax policies can be a way to use the currently popular market forces to increase incentives for small families in the general population. The tax deductions and credits for dependent children could be limited to two children per family, for instance; or the amounts could be sharply lowered for each subsequent child after the first. Thus, the $500 annual tax credit per child recently enacted could be changed to $500 for the first child, $250 for the second, $125 for the third, and so on. Some other countries have made use of school fees, subsidized housing, and other mechanisms to create incentives for small families. Unfortunately, such policies may have the unanticipated effect of handicapping children as wen, so they should be complemented by others carefully designed to meet the needs of existing children.

In the 1970s, partly in connection with the Population Commission's research, many proposals for encouraging lower birth rates in the United States without violating constitutional rights were put forward.(105) A study in 1982 by demographer and law professor Larry Barnett ventured beyond tax law revisions and explored constitutional rights of privacy, ownership rights, resource scarcities, housing policies, school fees, sex roles, marriage regulations, and immigration regulations as potential mechanisms for regulating population growth.(106) He also considered how population growth has necessitated an increase in regulations of many kinds, including environmental regulations.

However, the discussion regarding the United States became muted when the total fertility rate plunged to 1.8 in the mid-1970s and remained near there into the 1980s. The topic only began to resurface as fertility crept up again to 2.0 and immigration rates rose rapidly in response to recent policy changes.(107) This time, however, the rising birth rate was largely ignored, while attention focused on the influx of immigrants, leading to possibly unconstitutional changes in immigration policy in 1996.(108)

The decade of the 1970s also was a time when various writers suggested more extreme policies for societies with rapid population growth. These policies ranged from the mild, such as tax incentives and housing limitations, to the Draconian, such as "tradeable birth permits," to the wholly impractical (to say nothing of the moral implications), such as adding sterilants to water supplies.(109) Indeed, the ethical and moral dimensions of various population policies were much debated at that time.(110) Fortunately, it seems that for the developing nations, which have accounted for most of the post-World War II population explosion, a combination of modernization, an improvement in women's status, and the provision of family planning services has gone far toward reducing population growth, although the question of whether it is far enough soon enough remains open.

B. Overall Strategies

Of course, to avoid the most disastrous possible outcomes of the human predicament, efforts must be made to reduce all three of the major factors in the I = PAT identity,(111) not merely to concentrate on population control. If the size of the human population were gradually reduced to two billion people, and all those people attempted to live like Americans of today, then that population would not be sustainable; among other things, it would be using almost twice as much energy as the present global population of nearly six billion.

Thus, in addition to trying to reduce its numbers, and long before it passes its peak population size, civilization should strive to reduce its aggregate consumption and deploy the most environmentally benign technologies possible. Reductions in consumption, however, should first be concentrated in the rich nations. Such reductions are needed not only to lower overall impacts from further population expansion, to which we are demographically committed, but to help offset increasing consumption in developing nations. Most people in poor countries have access to too few resources and too little energy; meeting their needs will inevitably require increases in their per capita consumption. More efficient, environmentally benign technologies, however, could help contain the impacts that would inevitably attend an increase in per capita consumption.

IV. CONCLUSION

Population growth may be the paramount force moving humanity inexorably towards disaster. Although both overconsumption and the use of needlessly environmentally damaging technologies are major contributors, population growth is one of the most difficult to end rapidly because of its built-in momentum. But overconsumption may prove even more difficult to end. Theoretically, it could be ended in a few decades, as the substantial transformations of the U.S. economy at the beginning and end of World War II demonstrated. Yet what is physically and economically feasible may be socially much more difficult to achieve. Nevertheless, if we care about the world our descendants will inherit, our only responsible choice is to try.

(1) See, e.g., The 9 Lives of Population Control (Michael Cromartie ed., 1995) [hereinafter 9 Lives]. More often, environmental justifications for regulating population size are simply ignored or downplayed.

(2) Paul R. Ehrlich & John P. Holdren, The Impact of Population Growth, 171 Science 1212, 1212-13 (1971) [hereinafter The Impact of Population Growth]; see also Paul R. Ehrlich & Anne H. Ehrlich, The Population Explosion (1990) [hereinafter the Population Explosion]; John P. Holdren & Paul R. Ehrlich, Human Population and the Global Environment, 62 Am. Scientist 282, 288-90 (1974). An identity or identical equation is an equation true for all values of the variables; in this case I is defined by any values given to P, A, and T.

(3) A detailed discussion of the I = PAT equation can be found in Paul R. Ehrlich et al., Ecoscience: Population, Resources, Environment 715-35 (1977) [hereinafter Ecoscience].

(4) John P. Holdren, Population and the Energy Problem, 12 Population and Env't: A J. of Interdisc. Stud. 231, 231-92 (1991) [hereinafter Population and the Energy Problem].

(5) Id. at 245.

(6) Id.

(7) Anne H. Ehrlich & Paul R. Ehrlich, Ecosystem Risks Associated with the Population Explosion, in Predicting Ecosystem Risk 9, 9-21 (John Cairns, Jr. et a]. eds., 1992).

(8) See Paul R. Ehrlich et al., The Stork and the Plow: The Equity Answer to the Human Dilemma 194-96 (1995) [hereinafter The Stork and the Plow]; Paul R. Ehrlich & Anne H. Ehrlich, Healing the Planet 15-39 (1991) [hereinafter Healing the Planet]; see generally The Earth as Transformed by Human Action: Global and Regional Changes in the Biosphere Over the Past 300 Years (13. L. Turner II et al. eds., 1990) (discussing global cycles and resources, and humanity's impact on them).

(9) Healing the Planet, supra, note 8, at 19-30, 190-92, 276-77.

(10) The Impact of Population Growth, supra note 2, at 1212-17; Ecoscience, supra note 3, at 122-24, 343-45; Paul R. Ehrlich & Anne H. Ehrlich, Extinction: The Causes and Consequences of the Disappearance of Species 113 (1981); Nature's Services (Gretchen C. Daily ed., 1997); Healing the Planet, supra note 8, at 29-30.

(11) Population Reference Bureau, 1997 World Population Data Sheet (Wash., D.C., 1997) [hereinafter 1997 World Population Data Sheet]; United Nations, Division for Economic and Social Reformation and Policy Analysis, Population Division, World Population Prospects: The 1996 Revision, Population Newsletter No. 62 (U.N. Secretariat, New York, Dec. 1996).

(12) This figure refers to each individual's share of the flow of commercial energy through American society. Each individual human being uses an energy flow of about 100 watts (0.1 kW) to run his or her metabolic processes--about the amount of energy that flows through a lighted 100 watt bulb. Each person (bulb) then would use an amount of energy equal to 2400 watthours (2.4 kW hours) in a day. People are often confused because of the presence of the time factor in the description of energy quantity, rather than the rate of energy use. That is because "watt" is already a rate--one joule (0.2390 calories) per second.

(13) Population and the Energy Problem, supra note 4, at 246 & tbl. 7.

(14) 1990-1991 U.N. Statistical Yearbook 38, U.N. Doc. No. E/F.93.XVII.1, at 728-41 (listing electricity consumption for various nations).

(15) John P. Holdren & Patrick J. Gonzalez, 1990 World Population, GNP, and Commercial Energy Conversion, Address before the Energy and Resources Group, University of California at Berkeley (Oct. 1992).

(16) The New Prize: Energy Consumption in Developing Countries, A Survey of Energy, The Economist, June 18, 1994, at S1.

(17) 1997 World Population Data Sheet, supra note 11. Unless stated otherwise, all subsequent population figures are from this source.

(18) Paul R. Ehrlich, Me Limits to Substitution: Metaresource Depletion and a New Economic-Ecological Paradigm, 1 Ecological Econ. 9-16 (1989); The Population Explosion, supra note 2, at 42, 63.

(19) Gretchen C. Daily et al., Optimum Human Population Size, 15 Population and Env't A J. of Interdisc. Stud. 469, 475 (1994) [hereinafter Optimum Human Population Size].

(20) Population and the Energy Problem, supra note 4, at 245 & tbl. 5.

(21) There are three basic kinds of capital. The knowledge embodied in labor is human capital. The machines and other devices that labor uses in production (and which are fashioned by humanity and normally can be replaced when worn out) are human-made capital. Natural capital consists of features of the environment critical to production including renewable and non-renewable resources such as soils, trees, biodiversity in general, coal, and oil. Fikret Berkes & Carl Folke, Investing in Cultural Capital for Sustainable Use of Natural Capital, in Investing in Natural Capital: The Ecological Economics Approach to Sustainability 28, 129 (Ann-Mari Jansson et al. eds., 1994) [hereinafter Investing in Natural Capital].

(22) Lester R. Brown et al., Halting Land Degradation, in State of the World 1989: A Worldwatch Institute Report on Progress toward a Sustainable Society 20, 25 (1989).

(23) David Pimentel et al., Environmental and Economic Costs of Soil Erosion and Conservation Benefits, 267 Science 1117 (1995).

(24) Marc Reisner, Cadillac Desert: The American West and its Disappearing Water 455 (1986).

(25) Id. at 11, 455.

(26) Sandra Postel, Water and Agriculture, in Water in Crisis: A Guide to the World's Fresh Water Resources 56, 59, 60 (Peter Gleick ed., 1993); Sandra Postel, Last Oasis: Facing Water Scarcity 36, 54 (1992).

(27) See generally J. Donald Highes, Ecology in Ancient Civilizations (1997).

(28) Natural ecosystems provide humanity with free services such as: maintenance of the gaseous quality of the atmosphere, which regulates climate; generation and conservation of fertile soils; breakdown and dispersal of wastes and recycling of nutrients; control of most potential crop pests and vectors of disease; pollination of many crops; and direct provision of food from land and sea. Paul R. Ehrlich & Anne H. Ehrlich, The Value of Biodiversity, 21 Ambio 219, 221-24 (1992) [hereinafter The Value of Biodiversity].

(29) United Nations Environment Program, Global Biodiversity Assessment 155, 208 (V.H. Heywood ed., 1995); The Value of Biodiversity, supra note 28, at 225. The background rate is roughly equal to the rate at which speciation might replenish the stock.

(30) Peter Ward, the End of Evolution 67-68 (1994).

(31) See Paul R. Ehrlich & Anne H. Ehrlich, Betrayal of Science and Reason: How Anti-Environmental Rhetoric Threatens Our Future (1996) (collecting and analyzing various pieces of anti-environmental rhetoric).

(32) See generally Harold J. Barnett & Chandler Morse, Scarcity and Growth: The Economics of Natural Resource Availability 107-16 (1963).

(33) Norman Myers & Julian L. Simon, Scarcity or Abundance?: A Debate on the Environment 65 (1994). That preposterous statement was, of course, made by Simon.

(34) See generally Gregg Easterbrook, A Moment on the Earth: The Coming Age of Environmental Optimism (1995) (arguing that there is a substantial shift toward the positive in environmental news).

(35) Optimum Human Population Size, supra note 19, at 474.

(36) World Population Growth Slowing, But United Nations Still Estimates Total of 9.4 Billion by Year 2050, Population Division, Department for Economic and Social Information and Policy Analysis, United Nations, News Release, Nov. 14, 1996, available at <http://.www.un.org.>.

(37) Gretchen C. Daily & Paul R. Ehrlich, Population, Sustainability, and Earth's Carrying Capacity, 42 Bioscience 761 (1992).

(38) Population and the Energy Problem, supra note 4, at 250-53 (presenting an earlier version of the Holdren scenario); Interview with John P. Holdren, Energy & Resources Group, University of California at Berkeley (1996) (explaining the later version of the scenario) [hereinafter Holdren Interview].

(39) Population and the Energy Problem, supra note 4, at 251.

(40) Holdren Interview, supra note 38.

(41) Id.; Population and the Energy Problem, supra note 4, at 250 & tbl. 9.

(42) Holdren Interview, supra note 38.

(43) Population and the Energy Problem, supra note 4, at 231, 250.

(44) Thomas B. Johansson, Renewable Fuels and Electricity for a Growing World Economy, in Renewable Energy 1, 12 (Thomas B. Johansson et al. eds., 1993).

(45) James J. Zucchetto, Energy Production, Consumption, Environment, and Sustainability, in Investing in Natural Capital, supra note 21, at 431, 435; Johansson, supra note 44, at 43.

(46) Steven W. Mosher, Too Many People? Not by a Long Shot, Wall St. J., Feb. 10, 1997, at A18.

(47) The Population Explosion, supra note 2, at 159-61.

(48) See generally Marvin Harris & Eric B. Ross, Sex, Death, and Fertility: Population Regulation in Pre-Industrial and Developing Societies (1987); The Stork and the Plow, supra note 8.

(49) The Stork and the Plow, supra note 8, at 39, 296 n.25.

(50) Id. at 44-48, 299-300 nn.52-75.

(51) See id. at 103-37, 313-22 nn.1-108.

(52) See Calvin Goldscheider & William D. Mosher, Patterns of Contraceptive Use in the United States: The Importance of Religious Factors, 223 Studies in Fam. Plan. 102 (1991); Stanley K. Henshaw & Jane Silverman, The Characteristics and Prior Contraceptive Use of U.S. Abortion Patients, 20 Fam. Plan. Persp. 158 (1988); Elise F. Jones & Charles F. Westoff, The End of "Catholic" Fertility, 16 Demography 209, 216 (1979); Charles F. Westoff & Larry Bumpass, The Revolution in Birth Control Practices of U.S. Roman Catholics, 179 Science 41 (1973).

(53) Wolfgang Lutz, Future Reproductive Behavior in Industrialized Countries, in The Future Population of the World: What Can We Assume Today? 253, 260 (Wolfgang Lutz ed., 1996).

(54) See Jones & Westoff, supra note 52; William D. Mosher et al., Religion and Fertility in the United States: New Patterns, 29 Demography 199 (1992). But see Goldscheider & Mosher, supra note 52; William D. Mosher & Gerry E. Hendershot, Religion and Fertility: A Replication, 21 Demography 185, 189 (1984); Westoff & Bumpass, supra note 52, at 44.

(55) Peter J. Donaldson & Amy O. Tsui, The International Family Planning Movement, Population Bull., Nov. 1990, at 3; Bryant Robey et al., The Reproductive Revolution: New Survey Findings, Population Rep., Dec. 1992, at 11.

(56) See Nicholas D. Kristof & Sheryl WuDunn, China Wakes: The Struggle for the Soul of a Rising Power 228 (1994); H. Yuan Tien et al., China's Fertility Patterns Closely Parallel Recent National Policy Changes, 17 Int'l Fam. Plan. Persp. 75-76 (June 1991).

(57) Ecoscience, supra note 3, at 769.

(58) E.M. Viera & N.J. Ford, Regret After Sterilization Among Low-Income Women in Sao Paulo, Brazil, 22 Int'l Fam. Plan. Persp. 1, 32-37ff (Mar. 1996).

(59) See Donaldson & Tsui, supra note 55.

(60) Ecoscience, supra note 3, at 994-95.

(61) The estimate in the mid-1990s was 120 million couples, although there was some controversy surrounding the number. See John Bongaarts, The KAP-Gap and the Unmet Need for Contraception, 17 Population & Dev. Rev. 293-312 (1991); Bryant Robey et al., The Fertility Decline in Developing Countries, Sci. Am., Nov. 1993, at 60, 62 [hereinafter Fertility Decline]; C. Westoff & A. Bankole, The Potential Demographic Significance of Unmet Need, 22 Int'l Fam. Plan. Persp. 16-20 (Mar. 1996).

(62) 1997 World Population Data Sheet, supra note 11.

(63) Id.

(64) See Ansley J. Coale, The Decline of Fertility in Europe Since the Eighteenth Century as a Chapter in Demographic History, in The Decline of Fertility in Europe (Ansley J. Coale & Susan C. Watkins eds., 1986).

(65) Fertility Decline, supra note 61, at 64.

(66) Id.

(67) See The Population Explosion, supra note 2, at 56.

(68) See, e.g., Women's Education in Developing Countries: Barriers, Benefits, and Policies (M. Anne Hill & Elizabeth M. King eds., 1993); K. Subbarao, & Laura Raney, Social Gains from Female Education: A Cross-National Study, 194 World Bank Discussion Papers (1993).

(69) See generally Partha Dasgupta, An Inquiry into Well-Being and Destitution 358-61 (1993); John C. Caldwell, Direct Economic Costs and Benefits of Children, in Determinants of Fertility in Developing Countries, Vol. 1: Supply and Demand For Children 458 (Rudolpho A. Bulato & Ronald D. Lee eds., 1983).

(70) Healing The Planet, supra note 8; Gretchen C. Daily & Paul R. Ehrlich, Socioeconomic Equity, Sustainability, and Earth's Carrying Capacity, in Ecological Applications 6, 991-1001 (1996) [hereinafter Daily & Ehrlich].

(71) Daily & Ehrlich, supra note 70, at 995.

(72) See, e.g., Robert Repetto, The "Second India" Revisited: Population, Poverty, and Environmental Stress Over Two Decades 26 (1994).

(73) Id. at 12.

(74) Mexico-Population: Education and a Change in Mentality Are Key, Inter Press Service, Sept. 12, 1995, available in 1995 WL 10134277.

(75) Robin C. Duke & J. Joseph Speidel, Women's Reproductive Health: A Chronic Crisis, 266 JAMA 1846 (1991).

(76) Robert Repetto et al., Wasting Assets: Natural Resources in the National Income Accounts 27-44 (1989) (examining Indonesia's case in detail); see also Edward B. Barbier, Natural Capital and the Economics of Environment and Development, in Investing in Natural Capital, supra note 21, at 291-322.

(77) World Bank, World Development Report, Workers in an Integrating World 9 (1995).

(78) For a description of the Vatican's political activities at the United Nations Population and Development Conference at Cairo in 1994, see George Weigel, What Really Happened at Cairo, anti Why, in 9 Lives, supra note 1, at 129, 139-42.

(79) See supra notes 53-54 and accompanying text.

(80) See supra notes 12-18 and accompanying text.

(81) Abdul R. Omran & Farzaneh Roudi, The Middle East Population Puzzle, Population Bull., July 1993, at 1, 29-32; John R. Weeks, The Demography of Islamic Societies, Population Bull., Dec. 1988, at 1, 25.

(82) This is the case in many, but not all, Islamic societies. See Omran & Roudi, supra note 81; Weeks, supra note 81.

(83) See 1997 World Population Data Sheet, supra note 11.

(84) Id.

(85) See id.

(86) See Thomas J. Goliber, Africa's Expanding Population: Old Problems, New Policies, Population Bull., Nov. 1989, at 1, 45; John C. Caldwell & Pat Caldwell, High Fertility in Sub-Saharan Africa, Sci. Am., May 1990, at 118, 123-24.

(87) See supra notes 12-18 and accompanying text.

(88) Kevin Pollard, Population Stabilization No Longer in Sight for U.S., Population Today, May 1994, at 1, 2.

(89) Taxpayer Relief Act of 1997, Pub. L. No. 105-34, [section] 101(a), III Stat. 788 (1997) (to be codified at I.R.C. [section] 24).

(90) See generally Stephen Matthews et al., The Effects of Economic Conditions and Access to Reproductive Health Services on State Abortion Rates and Birth Rates, 29 Fam. Plan. Persp. 52 (1997) (analyzing various factors on abortion rates in the United States).

(91) Griswold v. Connecticut, 381 U.S. 479 (1965).

(92) Roe v. Wade, 410 U.S. 113 (1973).

(93) Carl Djerassi, New Contraceptives: Utopian or Victorian?, 6 Sci. & Pub. Aff. 5 (1991); Marquerite Holloway, Obstacle Course: Funding and Policy Stifle Contraceptive Research, Sci. Am., Apr. 1993, at 18-24; Carl Djerassi, The Bitter Pill, 245 Science 356 (1989); Marquerite Holloway, Obstacle Course. Funding and Policy Stifle Contraceptive Research, Sci. Am., Apr. 1993, at 18-24.

(94) Richard Stone, Controversial Contraceptive Wins Approval from FDA Panel, 256 Science 1754 (1992).

(95) See, e.g., Planned Parenthood of Southeastern Pennsylvania v. Casey, 505 U.S. 833 (1991) (upholding the right to abortion, but allowing restrictions on availability).

(96) The Stork and The Plow, supra note 8, at 103; see also Matthews et al., supra note 90.

(97) Interview with Jim Salzman, Assistant Professor of Law, American University (Mar. 1997); Foreign Assistance Act, Pub. L. No. 87-195, 75 Stat. 424 (1961).

(98) Roe v. Wade, 410 U.S. 113 (1973).

(99) Foreign Assistance Act of 1973 [section] 2(3), 22 U.S.C. [section] 2151b(f) (1994).

(100) See DKT Memorial FUN Ltd. v. Agency for Int'l. Dev., 887 F.2d 275, 277 (D.C. Cir. 1989) (upholding the Mexico City policy).

(101) See The Stork and the Plow, supra note 8, at 103.

(102) Commission on Population Growth and the American Future, Report: Population and the American Future (Gov't Printing Office, Wash. D.C., 1972) [hereinafter Commission Report]. Unfortunately, the main message of the report made little impression on the public because press attention focused on President Nixon taking exception to the recommendation that abortion be legalized. As it happened, abortion was legalized by the Supreme Court a year later. Roe, 410 U.S. at 113.

(103) This was pointed out more than a quarter-century ago by British writer Jack Parsons. See Jack Parsons, Population vs. Liberty (1971).

(104) Peter Edelman, The Worst Thing Bill Clinton Has Done, 279 Atlantic Monthly 43, 45 (1997).

(105) Arthur S. Miller & John H. Davidson, Jr., Observations on Population Policy-Making and the Constitution, 40 Geo. Wash. L. Rev. 618, 619 (1972); Johnson C. Montgomery, The Population Explosion and United States Law, 22 Hastings L.J. 629 (1971).

(106) Larry Barnett, Population Policy and the U.S. Constitution (1982).

(107) Pollard, supra note 88.

(108) Edelman, supra note 104, at 48-49.

(109) See generally Paul R. Ehrlich & Anne H. Ehrlich, Population Resources Environment: Issues in Human Ecology 32941 (2d ed. 1972) (discussing voluntary and involuntary population control measures throughout the world).

(110) Population Policy and Ethics: The American Experience (Robert M. Veatch ed., 1977).

(111) See supra notes 2-3 and accompanying text.

Paul R. Ehrlich, Bing Professor of Population Studies, Stanford University; co-author of The Population Bomb (1968), The: Population Explosion (1990), and Betrayal of Science and Reason (1996).

Anne H. Ehrlich, Senior Research Associate in Biological Sciences, Stanford University; co-author of The Population Bomb (1968), The Population Explosion (1990), and Betrayal of Science and Reason (1996).