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The population of the developing world has doubled since 1965 and now stands at 4.8 billion. This growth in human numbers has been a principal cause of a rising demand for food, water, and other life-sustaining resources in the past and will continue to be so for the foreseeable future. The United Nations projects that the developing-country population will reach 6.5 billion by 2020 and 8.2 billion by 2050 (the projected world total is 7.7 billion for 2020 and 9.4 billion for 2050). Although populations throughout the developing world continue to expand rapidly, the rate of growth is declining modestly. The average annual population growth rate was 2.4 percent per year in 1965, is estimated to be 1.7 percent today, and is expected to be 1.2 percent by 2020 (see table). The main cause of this decline is a revolution in reproductive behavior that began in the 1960s. Contraceptive use, once rare, is now widespread, and the average number of births per woman has fallen by half—from the traditional six or more in the 1960s to near three today. Fertility declines have been most rapid in Asia and Latin America. Relatively little change has occurred in Sub-Saharan Africa, but significant declines are under way in several countries in the region— Botswana, Kenya, South Africa, and Zimbabwe, for example.

WHY POPULATION GROWTH CONTINUES

Many analysts find it difficult to understand why massive further growth will take place despite declining fertility rates. First, the large decline since the 1960s still leaves fertility about 50 percent above the two-child level needed to stabilize the population. With more than two surviving children per woman, every generation is larger than the preceding one, and population continues to grow. The extent to which high (but falling) fertility rates remain a driving force for population growth varies by region. It is highest in Africa, with a current fertility rate of 5.3 births per woman, and lowest in Asia and Latin America, where fertility has dropped to just below 3 births per woman.

High fertility can in turn be attributed to two distinct underlying causes: unwanted childbearing and a desired family size of more than two surviving children. About one in five births is unwanted, and a larger proportion is mistimed. An estimated 25 million abortions are performed each year in developing countries—many of them under unsafe conditions. Many couples have large numbers of children because they fear that some children will die, and they want to be sure that enough children survive to assist them in family enterprises and support them in old age. In most developing countries, the completed family size desired by women still exceeds two children; in Sub-Saharan Africa, for example, desired family size is typically more than five children.

Second, declines in death rates—historically the main cause of population growth—will almost certainly continue. Higher standards of living, better nutrition, greater investments in sanitation and clean water supplies, expanded access to health services, and wider application of public health measures such as immunization will ensure longer and healthier lives in most countries. Only a few countries—mostly in Sub-Saharan Africa, where the AIDS epidemic is most severe—are the exception. Yet, the AIDS epidemic is not expected to eliminate population growth.

The third growth factor is what demographers call "population momentum." This refers to the tendency for a population to keep growing even if fertility were immediately brought to the replacement level of 2.1 births per woman with constant mortality and zero migration. Because the age structure of the population is young, the largest generation of adolescents in history will soon enter the childbearing years. Even if each of these young women has only two children, they will produce more than enough births to maintain population growth over the next few decades.

Of the three factors expected to contribute substantially to continued growth, population momentum is the most important. It will account for 76 percent of the expected increase between 2000 and 2020 in the developing world as a whole and for an even larger portion in Asia and Latin America. Further large increases in the population of the developing world are therefore virtually certain.

• High-quality family planning and reproductive health services should be expanded. Unwanted pregnancies occur when women and men who want to avoid pregnancy do not practice effective fertility regulation. Offering individuals and couples appropriate services has been a priority of many governments in the developing world. Despite considerable progress over the last several decades, however, the coverage and quality of family planning services remain less than satisfactory in many countries. In addition, some countries have imposed provider targets on family planning programs, limiting, for example, the number of intrauterine devices to be inserted or the number of sterilizations to be performed, thus actively interfering with trust between clients and providers. To ensure that family planning programs appropriately assist individuals in reaching personal fertility goals, family planning should be strictly voluntary and services should be linked with other reproductive health services. The quality of these programs can be improved by extending services to underserved areas; broadening the choice of methods available (including safe pregnancy termination where it is legal); improving information exchanges between client and provider; promoting empathetic relationships between client and provider; assuring the technical competence of providers; including men in programs; adding service elements to address related health problems, such as diagnosis and treatment of sexually transmitted diseases and treatment following unsafe abortion; and increasing public awareness of the value of and means available for fertility regulation, responsible and safe sex, and the location of services.
• Favorable conditions should be created for small families. Several social and economic measures have substantial effects on desired family size.

  (1) Increase educational attainment, especially among girls. As economies become less agrarian, the availability of mass education changes the value placed on large families and encourages parents to invest in fewer but "higher-quality" children, capable of entering the emerging labor markets. Higher levels of education are also associated with the spread of nontraditional roles and values, including less gender-restricted behaviors. Educated parents rely less on children for income and old-age support. Educated women want (and have) fewer children with higher survival rates, have higher earnings, and are more able to invest in their children’s nutrition and education.
  (2) Improve child health and survival. No developing country has had a sustained fertility decline without first having experienced a substantial decline in child mortality. A high child death rate discourages investments in children’s health and education and encourages high fertility because parents believe that excess births are required to ensure that at least the desired number of children will survive to adulthood.
  (3) Invest in women and provide them with economic prospects and social identities apart from motherhood. Improvements in the economic, social, and legal status of girls and women are likely to increase their bargaining power, giving them a stronger voice in family reproductive and productive decisions. As women’s autonomy increases, the dominance of husbands and other male household members is reduced, as well as the societal preference for men. As women’s status improves, the value of children as insurance against adversity (for example, in old age) and as securers of women’s social positions declines.

• Delay marriage and childbearing by addressing the needs of young women. While a young population age structure (the cause of momentum) is not amenable to modification, the age at which childbearing begins and its pace can be altered to offset momentum. Women in general, and young women in particular, are under pervasive pressure to fulfill societal expectations of appropriate feminine behaviors, especially with respect to their sexuality and fertility. This is a disguised form of coercion, as young women often have little choice about whether or not to have sexual relations, when or whom to marry, and whether to defer childbearing. Educating girls to the secondary level; including them in community development efforts, sports, and other publicly visible activities; and encouraging them to generate income begins to lead girls toward autonomy. Social power and economic authority for women are necessary counterpressures to traditional imperatives to marry and have children early.

Well-designed population policies are broad in scope, socially desirable, and ethically sound. They appeal to a variety of constituencies: those seeking to eliminate discrimination against women and improve the lives of children, as well as those seeking to reduce fertility and population growth. Mutually reinforcing investments in family planning, reproductive health, and a range of socioeconomic measures operate beneficially at both the macro and micro levels to slow population growth, increase productivity, and improve individual health and welfare.

For further reading see:
Bongaarts, J. 1994. Population policy options in the developing world. Science 263 (5148): 771–776.
Bongaarts, J., and J. Bruce. 1995. The causes of unmet need for contraception and the social content of services. Studies in Family Planning 26 (2): 57–75.
The Population Council. 1996. The unfinished transition. Population Council Issues Paper. New York.

John Bongaarts is vice president of the Policy Research Division and Judith Bruce is program director of Gender, Family and Development, International Programs Division, at The Population Council, New York.