DEVELOPMENT, POPULATION AND

Economic development refers to the structural transformation of human society from subsistence economy to urban-industrialism, and to the sustained rise in productivity and income that results. The transformation is seen in the structure of production, consumption, investment, and trade; in financial and other economic institutions; in occupations, educational levels, health conditions, and rural-urban residence; and in people's perceptions of the natural and social worlds and of their own agency. Political development is in some respects an overlapping process, yielding the values and institutions of the democratic state. Development, however, is commonly taken to mean economic development, with political development taken for granted.

Development is linked in various ways to population change. The transformation in demographic regimes from high to low birth and death rates–the demographic transition–can be added to the list of structural changes constituting development: Indeed, in terms of its direct effect on human wellbeing and its social and economic implications, it is arguably the most important of those changes. Population growth, unleashed by sustained mortality decline or by migration, is a force of its own in the development process, sometimes seeming to promote development, more often impeding it, and always diluting its achievements. While countries are the principal level at which such relationships have their effect, the influence of population change can extend to broader regional development and even to the global economy, with implications too for geopolitics and major environmental systems. Breaking down population growth by age group, source of growth (natural increase versus migration), and other characteristics reveals further links. The subject of population and development is concerned broadly with all such interactions: with how populations and economies impinge on each other and with the consequences that ensue.

Scale and Pace of Development

In the early 1800s, with industrialization barely underway, the world population stood at one billion; as late as 1930 it had reached just 2 billion; by the end of the twentieth century it had passed 6 billion. While dramatic enough to be described as an "explosion," this growth in population seems almost modest in comparison to the expansion of the global economy in the same period. Angus Maddison's index of gross world product (at constant prices, though the calculations required are complicated and inherently somewhat dubious over these time intervals) set at 1 in 1820, reaches 5 in 1929, 40 in 1990. It had probably exceeded 50 by 2000.

Along both dimensions this growth was extraordinarily uneven. The populations of Europe and North America expanded markedly over the nineteenth century as mortality yielded to improved living standards, the spread of education, and early public health measures. The region's share of the world population rose from about one-fifth to about one-third. Subsequently, mortality declines spread to Latin America, Asia, and Africa, creating a dramatic surge in population growth rates–and shifts in the global demographic balance that are relegating Europe and North America to the world's demographic margins (a 17% population share in 2000, a projected 12% share by 2050). The large reductions in mortality have been perhaps the most remarkable achievement of the post-World War II world. Life expectancy in the developing countries rose from about 40 years in 1950 to an estimated 64 years at the beginning of the twenty-first century.

Fertility levels followed, or seem to be following, the same regional course. In the West, aside from some forerunners (France and the United States), the decline got broadly underway in the late nineteenth and early twentieth century, spreading to the non-industrialized world after World War II but becoming widespread only in the 1960s or later. (Some regions, notably much of sub-Saharan Africa, had shown scant decline by the end of the twentieth century.)

The picture of regionally staggered onsets of demographic transition around the world, eventually (if only after a tenfold or more rise in population size) leading to conditions of low, zero, or perhaps negative population growth at low mortality levels, suggests a large measure of commonality in demographic experience. In cross-section, however, it is the diversity of demographic situations that is most striking. In the early decades after World War II arraying countries by mortality or fertility levels showed strongly bimodal distributions; in 2000, the bimodality had largely disappeared but the variance–reflecting the distance between leaders and laggards in the transition–remained high.

Economic growth used to seem well depicted by a similar kind of staged process, with poor countries successively reaching "take off" speed and embarking on rapid and sustained economic development. That expectation has only partially been borne out. In the worldwide emphasis on development that emerged with the ending of colonial rule after World War II, many countries experienced economic growth spurts, sometimes for long enough to be proclaimed miracles, but few by the end of the twentieth century had attained income levels comparable to those of the early industrializers. Many countries, and some whole regions (sub-Saharan Africa in the 1980s and 1990s), experienced periods of economic stagnation or retrogression. Using a standard measure of absolute poverty–expenditure averaging less than a dollar per day at 1990 purchasing power–the world's poor numbered around 1.2 billion persons (20% of the world's population) in the late 1990s.

The variegated global experience of growth in populations and incomes since the industrial revolution is depicted in summary fashion in Figure 1, based on the estimates of Maddison. (The years identified are those selected by Maddison as reflecting significant junctures in global development, but the smooth trajectories drawn in the figure skirt over intervening fluctuations.) The chart reveals the contrasts among major countries along both axes; the impressive steepening of the trajectories for China and to a lesser degree India; and the bleak performance of the African region (a doubling of population in the last quarter of the twentieth century with no overall gain in real per capita income).

Population Size and Development

Under the mercantilist doctrine that prevailed in early modern Europe, a larger population was valued as a source of a nation's wealth. Malthusianism punctured that belief. From Malthus onward, both popular and official opinion has tended to see population growth as a threat to development. Increases in production could only too easily be dissipated in additions to population rather than invested in capital accumulation. Resource scarcities–in arable land, later also in other natural resources–were seen as always looming on the horizon and were brought nearer by demographic expansion. Malthusian views lay behind India's concerns about its population growth both prior to and after independence. They were the basis of China's sudden conversion in the 1970s to a policy of hard-nosed birth control. They attained wide prominence in the West in the same decade through the Limits to Growth thesis propounded by environmentalists.

Malthusian thinking had a more checkered history in economics. Resource-dependence has been

FIGURE 1

steadily reduced as technology has advanced and human capital has grown. Non-renewable resources have found vastly expanded supplies in some cases and ready substitutes in others, banishing fears of an era of diminishing returns and rendering earlier worries about the imminent exhaustion of particular resources (coal in England, for instance) almost quaint. As Harold J. Barnett and Chandler Morse wrote: "the social heritage consists far more of knowledge, equipment, institutions, and far less of natural resources, than it once did" (1963: 11–12).

Resource constraints cannot be wholly assumed away, especially if development is equated with human well-being. Fresh water is often mentioned as a potentially limiting factor; so-called positional goods, such as unique environments, are by definition scarce. Standard measures of economic performance mask the effects of changes in the natural environment. "Environmental services"–for example, pollination of crops–may be a significant ingredient of human welfare, but yet remain statistically invisible. Aesthetic criteria generally, and hence a whole range of quality distinctions–in production and consumption as well as in environmental conditions–tend to be neglected when it comes to measurement.

Population-resource interactions are mediated by human institutions: markets or management regimes that serve to ration access to the resource by potential users. In some circumstances, these arrangements break down, or possibly they never emerged in the first place, leading to depletion or degradation as the demands on the resource increase. A classic stylized account of this, intended to model possible external effects (externalities) of population growth, is Garrett Hardin's "tragedy of the commons." The tragedy is the decline through overuse–and through institutional incapacity–of an open-access, common-property resource. Analogues of these local-level externality problems exist at higher levels of social organization, even internationally.

Population Growth and Development

Twentieth-century theorizing about development was influenced by neoclassical growth models that, in contrast to the "classical" model, allowed steady expansion of both economies and populations, with technological progress given a central role in outcomes. Any adverse effects of the overall scale of the economy in relation to its resources were assumed negligible–or outweighed by positive effects. Some economists saw population growth actually boosting technological change–a case supported by the work of Danish economist Ester Boserup (1910–1999) on long-run agrarian change. Many others saw population growth as a fairly neutral factor in development performance. The range of viewpoints is captured by two major reports on the subject from the U.S. National Academy of Sciences, from 1971 and 1986: The first found a strong case for limiting population growth, the second at most a very weak one. Whatever the theoretical arguments, in the post-World War II decades, at least until the 1980s, aggregate income data did not show a significant negative effect of population growth on development: At the country level the years of fastest economic and demographic growth often coincided.

If researchers ask not about the effects of rapid population growth on development but about those of reduced mortality and fertility, the consensus is clear. As well as its obvious and immediate meaning for a society's welfare and for what is sometimes termed its human development, high mortality has various adverse effects on economic development. There is the evident waste of human resources, often embodying substantial public and private investments in education and skills. The AIDS epidemic has been particularly damaging in this respect: In many of the worst affected countries the disease cuts a swath through the educated strata of the society. High mortality is also associated with heavy morbidity, and sometimes with impaired physical and cognitive development, with detrimental economic consequences. Within families, the death of a parent may harm the educational opportunities and broader life-prospects of the children: Again, AIDS mortality is the most prominent case in point, leading to a drastic rise in orphanhood and child destitution in a number of African countries. The benefits for development of improvements in health conditions and lower levels of mortality are thus clearly apparent.

The benefits of a fertility decline are somewhat less obvious–again, aside from the immediate welfare gain if it lessens "unwanted" births or improves reproductive health. Research suggests that lower fertility may improve access to health services and education, and more generally expand opportunities to escape poverty. One important route for such benefits is through a lowering of the child dependency rate: For a period of some two decades after a fertility decline there are fewer dependent children but no fewer workers, freeing up resources for investment. This straightforward proposition, advanced in a classic study by Ansley J. Coale and Edgar M. Hoover in the 1950s, was the main economic case for the worldwide expansion of family planning programs in the 1960s. Later it lost favor, along with many other arguments specific to developing economies, in the general disdain for development economics as a distinct branch of economics. It experienced a revival in the 1990s, coming to be seen by some as an important element in explaining the "Asian miracle"–the remarkable economic performance of East and Southeast Asian countries from the 1970s to the 1990s. The dramatic falls in birth rates in this region, beginning in the 1960s, are held to have yielded a "demographic bonus" of investment that boosted the development effort–not least, through improvements in human capital. However, the conditions under which any such bonus can be put to good use may be quite exceptional, lessening the value of the Asian miracle as a general policy lesson.

Promoting Demographic Transition

As discussed above, both mortality and fertility declines are favorable for development. The rapid population growth that is their usual accompaniment (since mortality typically falls first) is an offsetting factor, but moderates as the transition proceeds. These relationships can be viewed as positive feedbacks in the development process, forming a virtuous circle by which success breeds success: Sustained economic growth on the one hand and attainment of a modern demographic regime on the other. The components of population change are ingredients in the overall pattern of development, but for the most part they have the nature of dependent variables. Demographic transition is welcomed for the immediate welfare gains that low mortality and low fertility bring, but the proper policy focus to achieve those gains is on the broad development effort.

Many researchers and development planners, however, would adopt a much less passive stance on population policy. If there are proven means of intervention that can speed the mortality and fertility declines, then the gains both for immediate welfare and for the development effort can be reaped much earlier than would otherwise happen.

Mortality. For mortality, the appropriate means of intervention were evident. The long-running debate over the relative significance of the factors bringing about mortality improvement–transference of medical knowledge from the developed countries, expansion of public health facilities, and improved social and economic conditions–have been largely resolved, particularly through the pioneering work in the 1970s of demographer Samuel H. Preston.

Preston showed that there was a fairly tight but nonlinear relationship between life expectancy and per capita income among countries at a given time, and second that this relationship has shifted systematically over time. The relationship around 1990 is shown as a scatter plot (and fitted curve) in Figure 2, based on World Bank estimates: It is steep at low income levels, but flattens out at higher levels. Figure 2 also indicates the shifts in the relationship over time, drawing on sparser historical estimates. The major shifts have been twofold: (1) a decline in the per capita income level (in purchasing-power terms) at which this flattening takes place–that is, in the income level above which further income increases can be expected to make only slight contributions to improve mortality; and (2) an overall upward shift of the life expectancy-income relationship–a country with a given real per capita income in the early twenty-first century is likely to have considerably lower overall mortality than a country reaching the same income level some decades earlier would have had.

Cross-sectional analysis of this kind indicates that the effect of development on mortality is largest for countries at the lowest income levels. At the upper income ranges mortality is increasingly dissociated from economic change, reflecting both an educated demand for health services and the affluence to afford them. In the lower-and middle-income ranges, however, at any given income level there is a diversity of mortality outcomes across countries. Differences in income distribution, levels of education, public health expenditures, and the design and reach of the health system–all of them factors influenced by development policy–are the main contributors to that diversity.

Fertility. The degree to which fertility can be lowered by policy interventions has been a highly controversial issue in population and development studies, despite the casual assumption of many that the standard interventions–family planning programs–are of proven efficacy. But effective interventions of some sort are needed: The demographic bonus or any other economic advantages accruing from fertility decline are of interest because of the presumption that there are policy measures that can lower fertility other than through the normal course of development itself. Otherwise those advantages are reduced to the status of some helpful positive feedback generated by successful development.

At a broad level the factors behind fertility transition are not mysterious. Principally, there is a falling "demand" for children, traceable to a host of actual and anticipated changes in families' circumstances–in survivorship rates, in the family economy, in educational and labor market opportunities, and in related normative images of family and society. Also contributing to fertility decline are greater knowledge and availability of modern contraceptive methods and, in some situations, strong government efforts to promote smaller families. Development affects fertility mainly through alterations in the setting within which fertility decisions (and other decisions that incidentally bear on fertility) are taken. Three routes can be distinguished: (1) through alterations in the array of economic benefits and costs associated with marriage and childraising; (2) through shifts in social and administrative pressures on individuals and couples bearing on fertility-related decisions or their outcomes; and (3) through changes in internalized values concerning marriage and fertility instilled by education, socialization, and acculturation. The three routes are not wholly distinct, making for possibilities of double-counting.

(1) Economic benefits and costs. Fertility, like other kinds of behavior subject to individual choice, responds to changes in expected net economic benefits attaching to it. The increasing monetization of exchange relations that comes with economic development gives greater salience to this calculus. (Of course, no careful or even conscious calculation of benefits and cost need be assumed.) The economic shifts that take place are mostly in the direction of reducing the net benefits of high fertility.

The time entailed in childraising may be seen as more costly–for the poor, competing with opportunities to increase their earnings; for the better off, competing also with newfound forms of consumption.

Education beyond primary level becomes increasingly necessary for labor market success and its cost is often onerous even when supposedly publicly financed. This cost, together with other direct costs of children and the physical demands of their upbringing, is more likely to be borne fully by parents rather than shared among kin.

Social changes make any anticipated economic returns from children less assured. The insurance value of children is lessened as modern financial institutions emerge.

Improvements in health conditions presumably also affect the economics of fertility, altering individual planning horizons and parents' expectations of death or debility both for themselves and for their children.

Finally, government-supported family planning programs may lower the economic costs of birth control. How important those costs are, is disputed. Economist Lant Pritchett (1994, p. 25) points out that, under any reasonable assumption about the economics of children, those costs can be no more than a very small fraction of the (capitalized) net return–or net cost–anticipated from having a child.

(2) Social and administrative pressures. Social pressures from kin or community are probably felt less on the direct question of family size (except regarding childlessness and very small families) than on related matters such as age at marriage, approval or disapproval of particular practices of birth control, and restrictions on sex roles. Social influence entails scope for contagion and bandwagon effects. These effects are of course not confined to societies

FIGURE 2

experiencing demographic transition: It is likely that social pressures in contemporary low-fertility societies reinforce economic rationales for one-or two-child families by implicitly censuring family sizes above three.

In some countries in particular periods there have also been administrative pressures that bear directly on fertility. Such pressures peaked in the 1970s in Asia, principally in China and (more briefly) India, but also, less rigorously, in Indonesia and some other countries. Except for China, the pressures ebbed with the decline of fertility.

(3) Internalized values. The effects of values on fertility are not well understood or agreed upon. Some researchers believe them to have an independent effect on fertility, others as being rationalizations of behavior. They may be enduring realities–so that, for example, fertility decline could be a way of maintaining traditional family values in a changed economic setting. Or they may be altered by contact with new conditions. Some amount of value change is undeniable. For members of subsistence societies, almost osmotically but with many plausible transmission routes, perceptions of the family, of authority,

FIGURE 3

of the future, even of time, gradually come into alignment with those to be found in the modern industrialized world.

The combined net effect of these various changes has been strongly antinatalist, promoting the shift from quantity to "quality" of children. Disentangling the contributing factors to the fertility transition, however, has been a perennial source of argument, particularly over the putative roles of development (often narrowly construed as income growth) and ideational change (often construed as acceptability of family planning). The income-fertility relationship, shown as a scatter plot in Figure 3, makes clear both that a broad negative relationship exists and that there is a lot of variance remaining to be attributed to other factors. But such factors would necessarily include also the many aspects of development poorly captured by measures of income.

Population and Development Futures

In broad outline, the global economic and demographic trends observed over the second half of the twentieth century would support an expectation over the first half of the twenty-first century of continued, if uneven, improvement in economic conditions and, partly in consequence, an approaching end of the demographic transition. That demographic outcome, indeed, is the future built into the medium-variant population projections of the United Nations, which (in the 2000 revision) portray the world's fertility dropping from 2.8 children per woman in the 1990s to 2.1 (replacement level) by around 2050, and life expectancy increasing in the same period from 65 years to 74 years. The world population, under this scenario, would rise from 6 billion in 2000 to 9 billion in 2050, but by then the annual increment would have dropped from 80 million people to around 40 million–and zero (and perhaps negative) population growth would be in sight. Closely tied to these trends would be a substantial aging of population, continued rapid urbanization in the less developed regions, and continuation of the major shift in the balance of world population toward the South.

Both in evaluating this scenario and in probing its ingredients, consensus quickly wanes. The range of interpretations of past experience is magnified in looking ahead. The most sanguine outlook is sketched in economist Richard A. Easterlin's Growth Triumphant, in which the population explosion is a passing phenomenon, ushering in a future of sustained economic growth led by ever-higher material aspirations. Erstwhile poor countries successively build the complex economies and settlement densities already found in the rich countries. Economic globalization is frequently depicted as a route to such affluence, open to all, although bringing with it not just new opportunities but also new systemic fragilities.

More cautious or circumspect assessments of the future extrapolate emerging problems as well as favorable trends. Such problems include: supporting the necessary scale of transfer payments to the aged as their numbers multiply; avoiding fertility collapse to levels far below replacement, with its eventual implication of radical population decline; maintaining the quality of socialization and education of children in the face of crumbling families and weakened local communities; lessening the ecological damage associated with rising average consumption levels; and coping not only with the large remaining public health agenda in poor regions but also with new or reemerging infectious disease threats. The future food situation, though in the aggregate far from dire by many informed accounts, is increasingly technology-dependent and regionally disparate. The greenhouse effect, the atmospheric warming caused by increased amounts of carbon dioxide and other gases, has the potential to create ramifying changes in the environment, affecting crop production (perhaps positively), disease vectors, natural ecosystems, sea levels, and weather patterns. Greenhouse gas emissions are linked to population growth as well as to industrialization.

Population change will also have political consequences, and political developments, in turn, clearly have the capacity to modify future economic and demographic trends. "Failed states," according to Robert D. Kaplan, owe their ungovernability partly to population growth and the ecological degradation and poverty tied to it. Environmentally-related political instability, some have argued, will become common in many regions. But while examples of economic retrogression and associated political turbulence will surely continue to be found in the future, so too will cases of recovery and eventual return to paths of stable positive growth.

At the international level, the changes in relative population sizes and in age distributions among countries that are occurring will have major political implications. Combined with persisting economic differences they identify potential faultlines of international conflict. Large-scale migration from poor to prosperous countries is another politically sensitive issue that will not lessen in importance–filling some part of the demographic deficits created by very low fertility, and in doing so creating the increasingly ethnically-diverse societies of the Western world.

See also: Demographic Transition; Economic-Demographic Models; Fertility Transition, Socioeconomic Determinants of; Mortality Decline; National Security and Population.

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Geoffrey McNicoll