Population Sense and Nonsense

On the Issues
Demographics experts, warning of resource depletion and overcrowding, insist on the need for "population stabilization" through a reduction in childbearing. In their negative analysis, they have failed to note the falling prices of natural resources and the health explosion that has led to a huge expansion of human capital.

The spectacle of some 100 heads of state and 50,000 conferees gathering in Johannesburg for a fractious and even raucous UN summit on sustainable development may have left the impression of healthy intellectual ferment in the world of development economics. Alas, on the big issues, an unwholesome orthodoxy still prevails. Indeed, on the crucial issue of understanding world population trends, the U.S. government, the United Nations, European bureaucrats, and Third World elites agree more than they disagree. This is not a consensus to be cheered, but a shared impediment to understanding and relieving the problems that animated the Johannesburg proceedings.

"Sustainable development," as envisioned by its devotees, cannot be achieved without first "stabilizing world population," as the phrase now goes. The objective of "population stabilization" was solemnly endorsed fifteen years ago in the sustainable development movement's first canonical document--the Brundtland Commission's report, "Our Common Future." Since then, the quest to stabilize world population has been enthusiastically applauded by a wide array of international institutions and eminent persons: Kofi Annan and Warren Buffett, the World Bank and the U.S. State Department, the Ford Foundation and Al Gore.

What, exactly, does "stabilizing world population" mean? Despite its broad usage today, the banner itself is somewhat misleading, for those who carry it are not in fact concerned with stabilizing human numbers. If they were, one would expect to see them focusing more attention on Europe and Japan, where populations are currently projected to drop significantly over the next half-century. More immediately, human numbers are tumbling in the Russian Federation: Just last year the country suffered nearly a million more deaths than births. Yet supporters of population stabilization have not agitated for coordinated measures to lower Russia's death rate, raise its birth rate, and stanch its ongoing loss of population.

The reason for such insouciance about demographic decline by self-avowed population "stabilizers" is that their chosen standard does not quite describe their true mission. The actual aim, as the former executive director of the UN Population Fund has forthrightly declared, is "stabilization of world population at the lowest possible level, within the shortest period of time."

"Stabilizing" population, in fact, is code for the old project of anti-natal population control. The envisioned means of achieving stabilization is exactly the same: i.e., limiting the prevalence and reducing the level of childbearing around the world, especially in the Third World, and implementing measures to reduce births, particularly where fertility levels are deemed to be "unacceptably" high. This new version of the old anti-natalist crusade couches its arguments in the language of the social sciences and invokes the findings of the natural sciences to bolster its authority--but it cannot withstand the process of empirical review that lies at the heart of the scientific method. Whether they realize it or not, advocates of "world population stabilization" are devotees of doctrine, not followers of fact.

Mistaken Assumptions

The case for action to "stabilize world population" rests upon four premises. The first holds that we are self-evidently in the midst of a world population crisis--a crisis defined by rapid population growth, which is exacerbating "overpopulation." Typical is the assertion by Al Gore in his bestselling book Earth in the Balance that "the absolute numbers [of the world's population] are staggering"; and that "we can't acquiesce in the continuation of a situation that adds another . . . China's worth of people every decade."

The second premise is that current rates of world population growth are not only unsustainable over the long term, but are having direct and immediate adverse repercussions on living standards, resource availability, and political stability. The third premise implicit in the agenda of "stabilizing human population" is that reduced birth rates constitute the solution to the population problems adduced by premises one and two. The fourth premise bolstering this agenda is the presumption that well-placed decision-makers can effectively and expeditiously engineer the desired changes in worldwide population patterns through deliberate policy interventions. (Again, Al Gore: "Population specialists now know with a high degree of confidence what factors dramatically reduce birth rates.")

All of these premises are highly problematic. None of them is self-evidently true. Indeed, to the extent that any of these are testable, it would appear that they are demonstrably false.

Consider the assertion that the world is simply burdened by too many people. If this is offered as an aesthetic judgment, it cannot be refuted (de gustibus and all that). But how does it fare as a testable scientific proposition?

Population density, for example, might seem to be a reasonable criterion for "overpopulation." By that criterion, Haiti, India, and Rwanda (each with over six times the world's average population density) would surely qualify as "overcrowded," and Bangladesh--with almost twenty times the inhabited globe's average density--would be manifestly "overcrowded." By that same criterion, however, Belgium (1999 population per square kilometer: 333) would be distinctly more "overcrowded" than Rwanda (1999 population per square kilometer: 275). Similarly, the Netherlands would be more "overcrowded" than Haiti, Bermuda more "overcrowded" than Bangladesh, and oil-rich Bahrain three times as "overcrowded" as India. The most "overcrowded" country in the world by this measure would be Monaco: With a dire 33,268 persons per square kilometer in 1999, it suffers a population density over 700 times the world average. Yet as we all know, population activists do not agitate themselves about the "overcrowding" problem in Monaco--or in Bermuda, or in Bahrain.

Do other demographic measures provide a better reading of the population problem that so many take to be so very obvious? Perhaps we might look at rates of population growth. In the 1990s, sub-Saharan Africa was estimated to have the world's very highest rate of population growth--the United Nations Population Division put its pace at over 2.5 percent a year for the period 1995-2000--and sub-Saharan Africa is clearly a troubled area these days. However, if we look back in history, we discover that the United States had an even higher rate of population growth at the end of the eighteenth century: In the decade 1790-1800, the U.S. pace of population growth was 3 percent a year. Some today may believe that sub-Saharan Africa has too many people--but would they say the same about early frontier America?

We could continue combing for demographic measures that might help to clarify the nature, and pinpoint the epicenters, of the population crisis. But as our exercise should already indicate, that would be a fruitless task, because demographic criteria cannot by themselves unambiguously describe "overpopulation."

The crisis that advocates of population "stabilization" wish to resolve is impossible to define in demographic terms because it is a problem that has been mis-defined. In most minds, the notions of "overpopulation," "overcrowding," or "too many people" are associated with images of hungry children, unchecked disease, squalid living conditions, and awful slums. Those problems, sad to say, are all too real in the contemporary world. But the proper name for those conditions is poverty. It is a fundamental lapse in logic to assume that poverty is a "population problem" simply because it is manifest in large numbers of human beings.

Health Explosion

Let us now consider the second premise of "world population stabilization"; that rapid population growth and high fertility levels cause or exacerbate poverty, resource scarcity, and political instability. Describing these interactions comprehensively and accurately is a tremendous and subtle challenge. But we need not dwell on the intricacies of demographers' model-building to appreciate the flaws in this premise.

We can instead recall the reason for the twentieth century's "population explosion." Between 1900 and 2000, human numbers almost quadrupled, leaping from around 1.6 billion to over 6 billion; in pace or magnitude, nothing like that surge had ever previously taken place. But why exactly did the world experience a population explosion in the twentieth century? It was not because people suddenly started breeding like rabbits--rather, it was because they finally stopped dying like flies.

Between 1900 and 2000, the human life span likely doubled: from a planetary life expectancy at birth of perhaps thirty years to one of over sixty years. By this measure, the overwhelming preponderance of the health progress in all of human history took place during the past hundred years. Over the past half-century, worldwide progress in reducing death rates has been especially dramatic. Between the early 1950s and the late 1990s, according to estimates by the United Nations Population Division, the planetary expectation of life at birth jumped from under forty-seven years to sixty-five years. For low income regions, the leap was even more dramatic. This radical drop in mortality is entirely responsible for the increase in human numbers over the course of the twentieth century: The "population explosion," in other words, was really a "health explosion."

Now, with respect to economic development, the implications of a health explosion--of any health explosion--are, on their face, hardly negative. Quite the contrary: A healthier population is clearly going to be a population with greater productive potential. Healthier people are able to learn better, work harder, and engage in gainful employment longer than unhealthy, shorter-lived counterparts. Whether that potential translates into tangible economic results will naturally depend on other factors, such as social and legal institutions, or the business and policy climate. Nevertheless, the health explosion that propelled the twentieth century's population explosion was an economically auspicious phenomenon rather than a troubling trend.

Prosperity Explosion

All other things being equal, one would have expected the health explosion to contribute to the acceleration of economic growth, the increase of incomes, and the spread of wealth. And as it happens, the twentieth century witnessed not only a population explosion and a health explosion, but also a prosperity explosion. Estimates by the economic historian Angus Maddison, who has produced perhaps the most authoritative reconstruction of long-term global economic trends, demonstrate this.

Between 1900 and 1998, by Maddison's reckoning, global GDP per capita (in internationally adjusted 1990 dollars) more than quadrupled. Gains in productivity were globally uneven. Still, every region of the planet became richer. Africa's economic performance, according to Maddison, was the most dismal of any major global region over the course of the twentieth century. Yet even there, per capita GDP was roughly two and a half times higher in 1998 than it had been in 1900.

Suffice it then to say that the twentieth century's population explosion did not forestall the most dramatic and widespread improvement in output, incomes, and living standards that humanity had ever experienced. Though severe poverty still endures in much of the world, there can be no doubt that its incidence has been markedly curtailed over the past hundred years, despite a near-quadrupling of human numbers.

Maddison's estimates of global economic growth highlight another empirical problem with the second premise of the "population stabilization" project. With a near-quadrupling of the human population over the course of the twentieth century, and a more than fourfold increase in GDP per capita over those same years, global economic output has taken an absolutely amazing leap: Maddison's own figures suggest world economic output might have been over eighteen times higher in 1998 than it was in 1900. This means, of course, that humanity's demand for, and consumption of, natural resources has also rocketed upward. Yet the relative prices of virtually all primary commodities have fallen over the course of the twentieth century--for many of them, quite substantially.

Despite the tremendous expansion of the international grain trade over the past century, for example, the inflation-adjusted, dollar-denominated international price of each of the major cereals--corn, wheat, and rice--fell by over 70 percent between 1900 and 1998. By the same token: the Economist magazine's "industrial commodity-price index"--which tracks twenty-four internationally traded metals and other commodities--registered a decline of almost 80 percent between 1900 and 1999.

This seeming paradox of exploding demand for resources and simultaneous pronounced declines in real resource prices should be especially arresting to the reader with essentially Malthusian sensibilities. In the most fundamental sense, after all, prices convey information about scarcity--and they would seem to be indicating that the resources humanity makes economic use of have been growing less scarce over the course of the twentieth century. There are sound explanations for this paradox--but the "stabilization" project's second premise, which holds that population growth must result in increasing resource scarcity, is hardly able to provide it.

The third premise of the population stabilizers--that birth rates must be lowered to mitigate the adverse economic, resource, and political consequences of rapid population growth--requires absolutely no substantiation if one is already a true believer in the anti-natalist creed. For the empirically inclined--those who must be convinced that a problem exists before consenting to the public action proposed to redress it--the shakiness of the first two premises means there is barely any foundation remaining to support the third.

The Mystery of Fertility Change

But suppose we nonetheless persist in believing that there is a pressing need to take public action to lower worldwide birthrates. It would not necessarily follow that the desired result could be achieved--or achieved at an acceptable cost--or achieved voluntarily. Here lies the pivotal importance of the fourth premise of the population stabilizers: namely, that a cadre of "population specialists" know how international birth rates can be lowered, and that these specialists can provide policymakers with reliable advice about the interventions that will bring about fertility declines.

Alas, the plain fact is that careful students of child-bearing patterns through history have not uncovered the magic formula that explains why fertility changes occurred in the past--much less identified the policy levers that can be manipulated to determine how these trends will unfold in the future.

What demographers call "secular fertility decline"--the sustained, long-term shift from big families to small ones--showed up for the first time in Europe, about 200 years ago. But it did not begin in England and Wales--then perhaps the most open, literate, and industrialized part of the continent, if not the world. Instead it began in France, a country then impoverished, overwhelmingly rural, predominantly illiterate--and, not to put too fine a point on it, Catholic. Clearly, the "modernization" model does not plausibly explain the advent of fertility decline in the modern world. And, unfortunately, alternative models do not fare much better. Reviewing the theories of fertility decline in Western Europe and the evidence adduced to support them, the historian Charles Tilly wrote, "The problem is that we have too many explanations which are plausible in general terms, which contradict each other to some degree and which fail to fit some significant part of the facts." What was true for Western Europe at the onset of this process holds equally for the rest of the world today.

Al Gore's Earth in the Balance exemplifies the thinking of many current proponents of "world population stabilization" in its list of factors assumed to be instrumental in achieving sustained fertility reductions:

High literacy rates and education levels are important, especially for women; once they are empowered intellectually and socially they make decisions about the number of children they wish to have. Low infant mortality rates give parents a sense of confidence that even with a small family, some of their children will grow to maturity . . . and provide physical security when they are old. Nearly ubiquitous access to a variety of affordable birth control techniques gives parents the power to choose when and whether to have children. [Emphasis in the original]

Each of these three objectives may well be desirable in its own right, entirely irrespective of its influence on birth rates. As purported "determinants" of fertility change, however, the explanatory and predictive properties of these three factors leave a great deal to be desired.

For instance, according to the World Bank, the adult illiteracy rate for both males and females was higher in 1998 in Mongolia than in Tanzania--but Tanzania's fertility level in 1998 was more than twice as high as Mongolia's (5.4 vs. 2.5 births per woman). Tunisia and Rwanda were said to have almost identical rates of adult female illiteracy (42 percent vs. 43 percent), yet Tunisia's fertility level is put at just over replacement (2.2) while Rwanda's is almost three times higher (6.2). And although Bangladesh's female illiteracy rate is still placed at over 70 percent, the country's fertility level is said to have fallen by almost half between 1980 and 1998. Iran's total fertility rate is said to have plummeted by a remarkable 60 percent--from 6.7 to 2.7--over those same eighteen years. But presumably the Iranian revolution is not what proponents of "population stabilization" have in mind in arguing that the intellectual and social empowerment of women lead to smaller families.

Infant mortality provides scarcely more information about fertility change. By the UN Population Division's projections, for example, Jordan's infant mortality rate was about the same as Thailand's in the early 1990s--but where Thailand's fertility level at that time was below replacement, Jordan's was above five births per woman per lifetime. Such examples can be multiplied. The onset of sustained fertility decline in France took place during a period (1780-1820) when the country suffered an estimated average of almost 200 infant deaths for every 1,000 births. No country in the contemporary world suffers from such a brutally high infant mortality rate--yet a number of countries with considerably lower infant mortality rates than prevailed in Napoleonic France have yet to enter into fertility decline.

As for the relationship between fertility and the availability of modern contraceptives (or national programs to subsidize or encourage their use), inconvenient facts must once again be faced. The utilization rates for modern contraceptive methods are not a reliable indicator of a society's fertility level. In the early 1990s, among married women ages fifteen to forty-nine, Zimbabwe's rate of modern contraceptive use was three times as high as Romania's (42 percent vs. 14 percent)--yet Romania's estimated total fertility rate was about 1.4 whereas Zimbabwe's was about 4.1. Syria's rate of modern contraceptive prevalence was likewise higher than Lithuania's (29 percent vs. 22 percent--yet Syria's total fertility rate was three times the Lithuanian level (4.6 vs. 1.5). Further such examples abound.

What is more, the independent influence of national population programs on national birth rates appears to be much more limited than enthusiasts are willing to recognize. A comparison of Mexico and Brazil, Latin America's two most populous countries, illustrates the point. Since 1974, the Mexican government has sponsored a national family planning program expressly committed to reducing the country's rate of population growth. Brazil, by contrast, has never implemented a national family planning program. In the quarter century after the introduction of Mexico's national population program, Mexican fertility levels fell by an estimated 56 percent. In Brazil, during the same period, fertility is estimated to have declined by 54 percent--an almost identical proportion. And despite the absence of a national family planning program, Brazil's fertility levels today remain lower than Mexico's.

In the final analysis, the single best predictor of fertility levels turns out to be desired fertility levels--the number of children that women say they would like to have. Perhaps this should not be surprising: Parents tend to have strong opinions about important matters pertaining to their family; parents tend to act on the basis of those opinions; and even in the Third World, parents do not believe that babies are found under cabbages. The primacy of desired fertility explains why birth rates can be higher in regions where contraceptive utilization rates are also higher: For it is parents, not pills, that make the final choice about family size.

For advocates of "stabilizing world population," the predominance of parental preferences in determining birth rates creates an awkward dilemma. If parental preferences really rule, and a government sets official population targets for a voluntary family planning program, those targets are not likely to be met. Indeed, if parents are permitted to pursue the family size they choose, national population programs can only meet their targets by complete and utter chance.

On the other hand, if a government sets population targets and wishes to stand a reasonable chance of achieving them, the mischievous independence of parental preferences means that voluntary population programs cannot be relied upon. If states, rather than parents, are to determine a society's preferred childbearing patterns, governments must be able to force parents to adhere to the officially approved parameters. (China's draconian enforcement of a one-child policy--through forced abortions, sterilizations, and infanticide--is only the most notorious example of a government's following through to its conclusion the inescapable logic of the "population stabilization" dogma.)

Whether they recognize it or not, advocates of anti-natal population programs must make a fateful choice. They must opt for voluntarism, in which case their population targets will be meaningless. Or they must embrace coercive measures. There is no third way.

Optimism on Population Growth

Fortunately for our troubled planet, humanity's demographic and development prospects have been seriously misconstrued by the pessimistic doctrine of "world population stabilization." While the prevalence of poverty across the globe is unacceptably great today--and will continue to be so in the future (after all, what level of poverty should be acceptable?--humanity has enjoyed unprecedented and extraordinary improvements in material living standards over the past century, and over the past few decades in particular. Those improvements are represented in the worldwide increases in life expectancy and per capita income levels that we have already reviewed.

The tremendous and continuing spread of health and prosperity around the planet betokens a powerful and historically novel dynamic that anti-natalists today only dimly apprehend. This is the shift on a global scale from the reliance on "natural resources" to the reliance on "human resources" as fuel for economic growth. The worldwide surge in health levels has not been an isolated phenomenon. To the contrary: It has been accompanied by, and is inextricably linked to, pervasive and dramatic (albeit highly uneven) increases in nutrition levels, literacy levels, and levels of general educational attainment. These interlocked trends point to a profound and continuing worldwide augmentation of what some have called "human capital" and others term "human resources"--the human potential to generate a prosperity based upon knowledge, skills, organization, and other innately human capabilities.

In a physical sense, the natural resources of the planet are clearly finite and therefore limited. But the planet is now experiencing a monumental expansion of human resources. And unlike natural resources, human resources are in practice renewable and in theory inexhaustible--indeed, it is not at all evident that there are any "natural" limits to the buildup of such potentially productive human-based capabilities.

It is in ignoring these very human resources that so many contemporary surveyors of the global prospect have so signally misjudged the demographic and environmental constraints upon development today--and equally misjudged the possibilities for tomorrow.

Nicholas Eberstadt is the Henry Wendt Scholar in Political Economy at AEI.
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