Journal Issue

Special section: population and development: Population growth: The principal themes of the Bank’s World Development Report 1984

International Monetary Fund. External Relations Dept.
Published Date:
September 1984
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Its magnitude and implications for development

Nancy Birdsall

This year’s World Development Report emphasizes three themes:

Rapid population growth is a development problem. Continuing rapid population growth on an ever larger base is likely to mean a lower quality of life for millions of people. The main cost of such growth, borne principally by the poor in developing countries, has been and will be lost opportunities for improving people’s lives.

There are appropriate public policies to reduce fertility. Proposals for reducing population growth raise difficult questions about the proper domain of public policy. Family and fertility are areas of life in which the most fundamental human values are at stake. The 1983 World Development Report, on management in development, advocated reducing the direct role of government in many countries, stressing the importance of appropriate incentives (especially prices) to foster development. The 1984 Report appears to be a complete turnaround, advocating quick and forceful public action in an area where private rights are paramount. In fact, the two positions are consistent, since the earlier Report had also stressed the importance of focusing government initiatives on priority areas. The 1984 Report outlines the underlying logic for a public policy to slow population growth and stresses policies that change the “signals”—in a broad sense, the incentives—that encourage high fertility.

Experience shows that policy makes a difference. In the past two decades, and especially in the past ten years, fertility has fallen substantially in many countries in the developing world in response to public measures to reduce it.

Experience and prospects

Until the twentieth century, prosperity and population increase went hand-in-hand. In the eighteenth century, as living conditions began to improve steadily, world population growth accelerated slightly (to a then fast pace of 0.5 percent a year)—fastest in Europe and North America, where economic growth was taking hold.

In the twentieth century, world population growth accelerated dramatically, to 1 percent a year until almost 1950 and then to an unprecedented 2 percent, nearly doubling world population between 1950 and today (see chart). But population growth in the twentieth century has been concentrated where income is low; particularly since 1950, population growth has been concentrated in low-income developing countries. This delinking of population growth and prosperity occurred in part as improved public health and communications brought mortality down even where gains in living standards were small. Of the 1984 global population increase of about 80 million, more than 70 million will be in the developing countries, which already contain about three quarters of the world’s inhabitants. A combination of continued high fertility and much reduced mortality has led to population growth of between 2 and 4 percent a year in most low- and middle-income countries (compared with 1 percent and less in most developed countries). Growth at 3 percent a year means that in 70 years population grows eightfold; at 1 percent a year it merely doubles (see box).

The World Development Report 1984 was prepared by a team led by Nancy Birdsall and comprising Martha Ainsworth, Rodolfo Bulatao, Dennis Mahar, William McGreevey, Nicholas Prescott, and Gurushri Swamy. Deepak Lai, Peter Miovic, and Martin Wolf contributed to the section on global economic issues. The work was carried out under the general direction of Anne O. Krueger and Costas Michalopoulos. See back cover for information on ordering the Report.

For developing countries as a group, population growth rates have recently slowed somewhat, from a peak of 2.4 percent in 1965 to about 2 percent today. But further declines will not come automatically. Most families in developing countries (apart from China) now have at least four children, and rural families have five or more. In a few countries where fertility fell in the 1970s, there is evidence that it has leveled off recently, at still fairly high levels, while in much of Africa and Central America population growth rates are rising and could rise still further. Furthermore, population momentum means that growth rates in developing countries will remain high for several decades even if couples have fewer children; because of the large numbers of young people now entering childbearing age, absolute annual increases in population are likely to rise over 80 million people a year and remain that high well into the next century.

If the assumptions underlying the “standard” projections of the World Bank are correct, world population will rise from almost 4.8 billion today to almost 10 billion by the year 2050—the population of today’s developed countries increasing from about 1.2 billion to 1.4 billion, and that of those countries now classified as developing increasing from 3.6 billion to 8.4 billion. By the time world population stabilizes (at over 11 billion in about 2150), the population of India would be 1.8 billion, making it the most populous nation on earth. Bangladesh, a country about one quarter the size of France, would have a population of 430 million. Sub-Saharan Africa and South Asia would account for about 50 percent of the world’s inhabitants, compared with about 30 percent today.

Post and project world population, A.D. 1–2150

Source: World Bank World Development Report 1984

The arithmetic of population growth

Most countries have either rapid or slow population growth rates: the “rapid” growth countries of Africa, Asia, and Latin America have annual growth rates between 2.0 and 4.5 percent, while the “slow” growth countries, primarily the industrial nations, have growth rates below 1 percent. A few countries, including China, have growth rates between 1 and 2 percent. Because of compounding, small differences in annual growth rates over long periods make a big difference in population increases. An average growth rate of 1 percent a year over 100 years would result in a population 2.7 times as large. But a rate of 2 percent would cause it to be 7.4 times larger; a rate of 3 percent, 20 times larger; and a rate of 4 percent, 55 times larger. The population of Zambia is now about 6 million; it would grow to more than 120 million in 100 years, if growth continued at the present rate of 3.4 percent.

High population growth rates in today’s developing countries are due to two factors: high fertility (between four and eight births to each woman) and the momentum created by high fertility and falling mortality in the past, which means that women entering childbearing age are a large proportion of the total population and that the next generation of women can outnumber the previous one. Because of this momentum, the birth rate can remain high and the total number of births can increase even if the number of births per woman declines.

In some countries of Asia and Latin America, even where fertility has declined, average annual increases in population size are larger now than they were in 1965. Brazil’s total fertility rate fell from about 5.8 in 1965 to 3.9 in 1982. Yet the annual number of births increased, from about 2.9 million a year in the late 1950s to about 3.7 million a year in the early 1980s. The World Bank now projects that total fertility will fall to 2.1 by 2025. Yet by that year the total number of births will have increased to nearly 3.9 million a year.

To see how much of total population growth is due to momentum alone, imagine a population in which the fertility rate declines instantaneously to replacement level. (The exact number will be more than two, varying from country to country, and from period to period, because of different mortality rates. In the United States today, a total fertility rate of 2.12 is considered to be the replacement rate.)

The distribution of the population of Senegal in 1980 by sex and by five-year age groups is illustrative (see chart). The 1980 pyramid has a wide base and a narrow top, showing that each five-year age group is exponentially larger than the one preceding it. The 2020 pyramid (actually two figures superimposed) shows the population distribution for that year under two different assumptions: (1) fertility gradually declines, in keeping with standard Bank country projections for Senegal (the broader pyramid); and (2) fertility instantaneously falls to replacement level (the narrower pyramid). The broader 2020 pyramid, which assumes gradual fertility decline, is shaped like the 1980 pyramid but is almost three times larger. The narrower 2020 figure has a different shape than the 1980 pyramid. Its base has not expanded, yet its area is 1.6 times larger; this is the growth generated by momentum alone.

In fact, the narrower pyramid does not even show the full effect of momentum, which would not have run its course until after 2020. Even if fertility rates in Senegal dropped to replacement level now, by the time the population stops growing, the narrow pyramid would be 2.2 times larger in area than the 1980 pyramid. In other words, the population of Senegal would increase 2.2 times from the force of momentum alone.

Age structure in Senegal, 1980 and 2020

Source: World Bank, World Development Report 1984.

1Divided into five-year age groups.

In some respects the assumptions underlying these projections—including that fertility will fall to replacement level in some developing countries by 2005, and in all by 2045—are optimistic. Even with rapid income growth and advances in literacy in the next two decades, the poorer countries of Africa and South Asia are not likely to reach the income and literacy levels that triggered fertility declines in such countries as Brazil, the Republic of Korea, and Malaysia in the 1960s. Yet their fertility is projected to decline significantly. Even if it does, their populations will more than double in the next 50 years.

Alternative projections demonstrate two points: how much population growth there will be with even faster fertility decline than the “standard” projection allows for; and how much of a difference a more rapid fertility decline could make. By the year 2050, for instance, Kenya, with an immediate and rapid decline in fertility, would have 70 million rather than 120 million people, compared with 18 million today. More rapid declines in mortality are also possible—but they would not boost population growth as the mortality declines of the 1950s and 1960s did. For most of the developing world, the time when declining mortality produced surges in population is passing rapidly. In part this is because mortality, although still high compared with developed countries, has already fallen considerably. In addition, declines in mortality affect population growth less when fertility is falling, as is and will be the case in most countries.

A development problem

Returning to the first of the themes emphasized by the Report, there are three major reasons why rapid population growth slows development. First, it exacerbates the difficult choice between higher consumption now and the investment needed to bring higher consumption in the future. Per capita resources are lower the faster population grows, making investment in “population quality” difficult. Yet ultimately the key to development is more educated and skilled people. For example, in most developing countries, the high fertility and falling infant mortality of the mid-1960s mean that about 40 percent of populations now are aged 15 or younger. Many countries face a doubling or tripling of their school-age population by the end of the century. In Malawi, with rapid fertility decline could come savings of more than 50 percent as the numbers of children entering school by the year 2015 rise more slowly. School quality in Malawi (as in many other developing countries) is poor; the savings could be used to improve it.

Second, in many countries where populations are still highly dependent on agriculture, population growth threatens what is already a precarious balance between scarce natural resources and people. In part, the problem arises because rapid population growth slows the transfer of labor out of low-productivity agriculture into modern agriculture and other modern jobs. In many countries, much of the huge projected increases in the size of the labor force will have to be absorbed in agriculture, a difficulty which today’s developed countries never faced. In Kenya, 70 percent of the labor force will probably still be working in agriculture as late as 2025, and the number of workers will be twice what it is today. The result is likely to be continuing low incomes for many families and, in some cases, stress on traditional agricultural systems and environmental damage that threatens the economic well-being of the poor. In parts of Africa, Bangladesh, and China, population pressure has already forced people to work harder just to maintain household income in traditional agriculture. In the lowland areas surrounding the River Ganges in South Asia, population growth and competition for land have forced many people to live too close to the water, in the path of the annual floods.

Finally, rapid increases in population make it hard to manage the adjustments that are necessary to promote economic and social change. As the accompanying article by Dennis Mahar shows, high fertility is a major contributor to rapid urban growth. Cities in developing countries are growing to unprecedented sizes. Such growth poses enormous new problems of management even to maintain—let alone improve—living conditions for city residents.

There are several reasons why population growth in developing countries is a greater economic burden today than it was in today’s developed countries in their periods of economic transformation.

• Population growth is now much more rapid—in Europe and Japan in the nineteenth century, population growth seldom exceeded 1 percent a year.

• The large-scale emigration that occurred in nineteenth century Europe is not possible from today’s developing countries. Nearly 45 percent of the increase in the population of the United Kingdom during 1846–1932 emigrated, compared with 0.5 percent of the increase in Asia between 1970 and 1980.

• Compared with Europe, Japan, and North America in their periods of fastest population growth, income in developing countries is still low, human and physical capital are less built up, and in some countries political and social institutions are less well established.

• Many developing countries whose economies are still largely dependent on agriculture can no longer draw on large tracts of unused land. In Japan and the United Kingdom by the 1880s, population growth in rural areas had ended; in much of Asia and Africa today, rural population growth still exceeds 2 percent a year (even taking into account migration to urban areas) implying a doubling of population size in rural areas every 40 years.

Countries in which education levels are already high, in which much investment in transport and communications systems is in place, and in which political and economic systems are relatively stable are well equipped to cope with rapid population growth. This is true whether or not their natural resources are limited or their countries already crowded—but these also tend to be the countries in which population growth is now slowing.

The problem of rapid population growth also affects countries with untapped natural resources, making it difficult to develop the human skills and administrative structures needed to exploit those natural resources. In Brazil, Ivory Coast, and Zaire, for example, the development of unused land will require large complementary investments in roads, public services, and drainage and other agricultural infrastructure.

Where the amount of new land or other exploitable resources is limited—as in Bangladesh, Burundi, China, Egypt, India, Java in Indonesia, Kenya, Malawi, Nepal, and Rwanda—the short-run difficulties caused by rapid population growth are more obvious. Increases in agricultural yields are possible, and the expansion of manufacturing industry could provide exports to pay for extra food imports. But both solutions require costly investments, the development of new institutions, and numerous economic and social adjustments—all of which are easier if population is growing only slowly.

The consequences of high fertility also take their toll at the family level, particularly on children from families that are both large and poor. In Brazil, for instance, more than 60 percent of all children live in the poorest 40 percent of households that earn just 10 percent of the country’s total income. From one generation to the next, an unequal distribution of income can be caused by, and contribute to, an unequal distribution of opportunities and skills, as large family size and low investments in children reinforce each other.

Need for a public policy

It is the poor, with little education, low and insecure income, and poor health and family planning services who have many children; yet it is also the poor who lose out as rapid population growth hampers development. It is this seeming paradox that provides the starting point for understanding the need for appropriate policies to reduce fertility. There are several good reasons why, from the point of view of poor parents, the economic costs of children are low, the economic (and other) benefits of children are high, and having many children makes economic sense.

Demographic terms

Population growth rate: annual rate of population change due to natural increase and net migration (as a percentage of the base population).

Replacement-level fertility: the level at which a cohort of women has, on average, only enough daughters to “replace” itself (the higher mortality, the higher replacement-level fertility).

Total fertility rate: average number of live births to a woman during her lifetime if she had children at each age in accordance with prevailing age-specific fertility rates.

• Where wages are low, income lost by the mother during a child’s infancy may be easily recouped by the child later on.

• Where schooling opportunities are limited, the investment potential of children is not apparent. When schooling opportunities improve, and education becomes more clearly the key to future success for children (and their parents), parents want fewer, better-educated children.

• Given high mortality, parents may feel the need to have many babies to be sure that a few survive. Where boys are more important than girls—say, for security in old age—parents may need to have five children to be sure one son survives.

• For many poor parents, the need for support in their old age outweighs the immediate costs of children. For the rural poor, children are the best possible “annuity” for old age—not subject to theft, inflation, or the jealousies of neighbors. (Even land is an asset that may be difficult to manage without adult children once parents become old.)

• In some developing countries family systems encourage high fertility. For young women who have few other options, early marriage and many children may be the safest route to a satisfying adulthood and a relatively secure old age.

• Limited information about, and access to, modern and safe means of contraception encourage high fertility among the poor.

Yet despite the apparent advantages of many children, it is not clear that, from a strictly economic point of view, parents always gain. Children may cost parents more than they expected. Any economic benefits may depend on circumstances parents cannot easily predict—whether they gain or lose access to land, whether their children are healthy, whether they have the right balance of sons and daughters. Even old-age support is not guaranteed if children die, move far away, or cannot themselves find good work.

Moreover, although parents may seem to gain from large families, children often lose. This is obvious when births are closely spaced; the resulting harm to the health and nutrition of mothers can cause low birth weight, early weaning, and poor health of children in the critical early years. Better spacing alone could reduce infant mortality by 10 percent in many developing countries. Early malnutrition contributes to and exacerbates later difficulties in becoming educated.

If parents have many children in the hope of economic gain, the first step in reducing fertility is to relieve their poverty and reduce their uncertainty about their own future. In this sense, the persistence of high fertility in a changing world is a symptom of lack of access: to health services, which would reduce the need for many births to ensure against infant and child mortality; to education, which would raise parents’ hopes for their children and would broaden a woman’s outlook; to social security and other forms of insurance for old age; to consumer goods and social opportunities that compete with childbearing; and to family planning services, which provide the means to limit births.

The Report gives two reasons for a public policy on population. First, in the transition from a traditional to a modern economy, the private gains from having many children may exceed the social gain. Poverty is an underlying cause; individual poor families may often have good reasons for wanting a large family. Yet society as a whole, and the poor in particular, may be worse off if population growth is rapid. Indeed, a poor couple may wish its neighbors would have fewer children, even as it has many.

One reason private and social gains differ is that parents themselves do not bear all the costs of their children. In most countries, the health and education costs of children are heavily subsidized by the public sector, as are roads, communications, and other public services that boost jobs and income. Even as some couples have many children because health services and schooling opportunities are limited, their large families make it more difficult for the public sector to extend such services to all. Yet one couple, on its own, is unlikely to give up the possible private benefits of children, when its individual sacrifice would provide only minuscule benefits to other families’ children and grandchildren.

The gap between private and social gains can be reduced; better educational and employment opportunities, especially for women, change the signals that encourage high fertility and provide alternative ways for parents to secure the benefits that they seek in having many children. Public support for organized family planning programs can make it as easy as possible for couples to choose the number and timing of their children, closing the gap between actual and desired family size, and bringing actual fertility closer to social goals. And incentives to encourage lower fertility are a way for society to compensate couples willing to forgo the private benefits of an additional child, bringing private and social goals closer. Through these policies, the public sector provides a way for people to make, in effect, a social contract with each other—to have fewer children.

The second justification for government action is that people may have more children than they would want if they had more information about—and better access to—easier fertility control. For example, couples may lack (or disbelieve) information about falling child mortality, or they may not be fully aware of the health risks, both to mothers and children, of many and closely spaced births. Even if they know about family planning, they may either not know how to practice it or lack ready access to modern contraception and be forced to rely on less effective traditional methods.

In this situation, the role of the government is critical. As a start, it can encourage parents in their desire to have fewer children simply by providing more information—about changing mortality and the health benefits of controlling fertility. It can encourage wider provision of modern contraceptives, including those supplied by private agents, especially in towns. But private suppliers are unlikely to provide the full range of family planning services, especially in remote areas. Many modern means of contraception can be made available only with medical support services, and there is little profit in disseminating information and contraceptives where distribution systems are poor, health care is limited, and demand is unknown and possibly limited. In many countries, government may need to subsidize or even organize contraceptive services.

The case for government support for family planning services is most obvious where couples want no more children but, often for lack of access to effective contraceptives, do not use contraception. An estimated 65 million couples in developing countries have such “unmet need” for family planning information and services. Many of these are poor, and many live in poorly served rural areas.

Successful experience

It was once assumed that reducing fertility in developing countries would require a typical sequence of economic advance: urbanization, industrialization, a shift from production in the household to factory production, and income growth to levels enjoyed by today’s developed countries. This view seemed to be confirmed by the fertility declines of the 1960s, which were largely confined to the industrial economies of Korea, Singapore, and Hong Kong.

But fertility declines in many other countries, beginning in the late 1960s and spreading in the 1970s, have been related to a different kind of development: education, health, the alleviation of poverty, and government effort to assure widespread access to family planning services. Declines in birth rates since 1965 have been much more closely associated with adult literacy and life expectancy than with GNP per capita. And several countries that have supported family planning services have significantly lower fertility than the norm for their income level, including China, Colombia, Egypt, India, Indonesia, Korea, Sri Lanka, and Tunisia. (Countries with relatively high fertility given their income include Algeria and Morocco, most countries of sub-Saharan Africa, and Venezuela.) In most of the low fertility countries, fertility has declined much faster than it did in today’s developed countries—both because of the availability of more effective modern contraceptives and the rapid expansion of educational opportunities in the postwar period.

Within regions, differences among countries are due in part to population policy effort. Fertility has fallen faster and to lower levels in Colombia, where family planning programs received government support starting in the late 1960s, than in Brazil, a richer country where central government involvement is minimal (see the article by Martha Ainsworth on country experience with population policy). It has fallen more in Egypt and Tunisia, countries with demographic objectives, than in their richer neighbor, Algeria. It has fallen more in India than in Pakistan; per capita income is low in both, but in Pakistan population policy has received less sustained support over the past two decades. The pattern of decline shows that differences in income, religion, and culture do not tell the whole story. Education, access to family planning services, the status of women, and economic and social policies that bring opportunities to the majority of people all make a difference.

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