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Rapid Population Growth Is Still A Problem

October 16, 1998
Population Council
Current trends in reproductive behavior differ sharply between regions and should not be confused, says Population Council vice president John Bongaarts. "In the already crowded developing world, despite plummeting fertility rates, both the number of births and population size will keep growing. The expected addition of several billion more people will hamper ongoing efforts to reduce poverty and achieve sustainable development."

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NEW YORK -- Current trends in reproductive behavior differ sharply between regions and should not be confused, says Population Council vice president John Bongaarts. "In the already crowded developing world, despite plummeting fertility rates, both the number of births and population size will keep growing. The expected addition of several billion more people will hamper ongoing efforts to reduce poverty and achieve sustainable development. On the other hand, in parts of the developed world, particularly Europe and Japan, already low fertility is causing consternation over the potential adverse effects of an aging or declining population. This concern should not be overblown, however, since reported fertility measures do not reflect the fact that couples are still having about two children, they're just having them at an older age. Fertility rates are not as low as they appear to be."

World Is Only At Mid-Point In Population Growth

Bongaarts points out in the October 16, 1998 issue of Science that contraceptive use in the developing world, once rare, is now widespread: the average number of births per woman has fallen by half, from the traditional six or more to near three today. This "revolution in reproductive behavior," says Bongaarts, has led some to speculate that "the world population explosion is over." But instead of being near the end of the "explosion" with today's population of 5.9 billion, Bongaarts comments, "we are just past its mid-point. After a record-breaking increase of 2 billion people over the past 25 years, the same increase is projected over the next 25 years, and a further expansion to 10.4 billion is expected by 2100."

Large increases in population growth are expected in Africa, Asia, and Latin America for three reasons, Bongaarts says:

* Fertility is still about 50 percent above the two-child level needed to bring about population stabilization. With more than two surviving children per woman, every generation is larger than the preceding one.

* Declines in mortality, historically the main cause of population growth, will almost certainly continue. Higher standards of living, better nutrition, expanded health services, and greater investments in public health measures have increased life expectancy by 50 percent since 1950. The unhappy exceptions will be life expectancy declines in most of those sub-Saharan African countries with severe AIDS epidemics.

* The historically largest generation of women about to enter the childbearing years will produce more than enough births to maintain population growth for decades even if they each have only two children, population momentum.Not A Birth Dearth, Either

Europe, North America, and Japan face quite a different demographic future, Bongaarts says, along with such rapidly developing Southeast Asian countries as Hong Kong, Korea, and Singapore, which also have experienced steep declines in population growth rates since 1960. But because of immigration, rising life expectancy, and/or population momentum, the populations in even these countries are projected to remain close to current levels for several decades, with modest increases expected (e.g. the U.S.) and small declines (e.g. in Europe).

Bongaarts feels that concern about underpopulation in developed countries has been exaggerated. Although observed fertility has reached historic lows in many developed countries and the percentage of women remaining childless is relatively high, it is likely that birth rates will not drop further and may even turn up. To support this conclusion, Bongaarts points to a puzzling discrepancy between expressed preferences for family size and measured fertility in most low-fertility societies.

In most low-fertility societies, the preferred family size is about two children and the actual childbearing experiences of women support this number, but this is not reflected in the most widely reported measure of annual fertility (the so-called total fertility rate).

"The measurement of this fertility rate picks up a slightly different picture than we get looking at women's actual reproductive histories," Bongaarts says. Women choosing to defer births to older ages temporarily contribute to today's baby bust (which reflects the measurement of the number of babies born each year), just as younger childbearing ages in the 1950s temporarily contributed to a baby boom. If women in a given country have the same number of children in their lifetime, but later in their lives than their predecessors, this will appear to be a reduction in annual birth statistics. Family size may in fact not be changing in nearly as dramatic a fashion as is suggested by the year-over-year aggregate birth statistics.

"These distortions," comments Bongaarts, "are temporary because they exist only while the age at childbearing is rising. Once women stop deferring births, the distortion disappears and the very low fertility rates observed in the developed world should rise closer to the 2 children most couples want."

For example, in France the annual total fertility rate has been reported to be well below the replacement level since the mid-1970s, but in actuality French women who have reached the end of their childbearing years report having 2.1 births on average, close to the preferred number.

Similar Discrepancies Exist In Many Other Developed Countries

In the U.S., fertility rose from 1.77 to 2.08 births per woman between 1975 and 1990 as the postponement of births stopped. It is therefore plausible to assume that fertility in Europe and Japan will not decline further and might even turn upward soon. It is unlikely, however, that fertility in these countries will rise all the way to replacement level because various constraints (e.g. divorce, desire to remain employed, rising costs of children, involuntary childlessness) prevent some couples from reaching their desired family size. The most plausible pattern is the one now assumed by the United Nations: a modest rise in fertility to a level somewhat below replacement, with large population declines unlikely.

Different Policies For Each Demographic Condition

Policy implications for both conditions, sizable population growth in developing countries and below-replacement levels in developed countries, call for different approaches, Bongaarts says. Indifference is not one of them. Concern over adverse consequences of additional billions of people in the poorer countries has "provided the principal rationale for past investments in voluntary family planning and reproductive health programs that help couples avoid unwanted childbearing. This effort should be strengthened and expanded to include social investments in young people, for example, girls' education that help offset population momentum and improve the quality of individual lives."

In the developed world, the potential adverse consequences of prolonged below-replacement fertility have led to "extensive discussions but little action," with most governments reluctant to pursue explicit pronatalist policies. Numerous policy options have been proposed to encourage childbearing, Bongaarts says, but, unfortunately, there is "little useful experience to draw on in assessing potential effectiveness. In rare instances where new measures to raise fertility were successfully implemented (for example, Sweden in the late 1980s) it is difficult to disentangle the roles of the specific components in a package of measures." Options include free or subsidized childcare, reduced taxes for families with children, paid parental leaves; and subsidized housing for young couples.


John Bongaarts is Vice President, Policy Research Division, Population Council. A noted demographer, Dr. Bongaarts received two major awards from the Population Association of America and an award from the National Institutes of Health. He is Chairman of the National Academy of Science's panel on population projections.

The Population Council is an international, nonprofit, nongovernmental institution that seeks to improve the wellbeing and reproductive health of current and future generations around the world and to help achieve a humane, equitable, and sustainable balance between people and resources. The Council conducts biomedical, social science, and public health research and helps build research capacities in developing countries. Established in 1952, the Council is governed by an international board of trustees. Its New York headquarters supports a global network of regional and country offices.

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Population Council. "Rapid Population Growth Is Still A Problem." ScienceDaily. ScienceDaily, 16 October 1998. <>.
Population Council. (1998, October 16). Rapid Population Growth Is Still A Problem. ScienceDaily. Retrieved May 24, 2024 from
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