Six Billion and Counting
Martin, Linda, Harvard International Review
Population Management at the Millennium
Last year marked not only the end of the century but also a demographic milestone: the world's population reached six billion. Should we be celebrating or worrying? The answer is both. Behind the number lies considerable demographic diversity. But demography is not necessarily destiny, as the consequences of population growth or decline are manifested through a filter of social and economic institutions. Nonetheless, demographic forces are powerful in their own right, and policies that influence population trends may be a cost-effective means of achieving broader goals.
Let's Do the Numbers
World population growth in the second half of the 20th century was unprecedented; it doubled from three to six billion between 1960 and 1999. The previous doubling from 1.5 billion took twice as long.
Increases in survival around the world in the postwar period have triggered this rapid growth. In more developed countries, life expectancy at birth has increased from 67 to 76 years over the last half century, while in less-developed countries it has soared from 41 to 65 years over the same period.
These are encouraging developments; in particular, the increased survival of infants and children meant that many parents in poorer countries could reach their family-size goals--in terms of surviving adult offspring--by having fewer children. Some parents were slower than others to realize this change. At the same time, other parents were reducing their goals for family size and choosing to invest in the quality of their children (by providing better education, for example) rather than in quantity.
Many parents did not have access to contraceptive technology that fit their needs and lifestyles and that did not have unacceptable side effects. The result was that fertility remained high in many of the poorer countries even as mortality fell, and population growth rose. Many governments intervened by developing public family-planning programs to help couples avoid unwanted pregnancies; in some cases, they established policies to encourage smaller family-size norms. The richer countries were important sources of funding and technical assistance, especially for family-planning programs. The justifications for intervention included the market failures of both family-planning information and services and couples not taking into account the full social costs of additional births as they made their private decisions.
In general, countries in Asia and Latin America have been successful in reducing fertility, as shown in Figure 1, and annual population-growth rates in the less-developed regions overall declined from a high of over 2.5 percent around 1965 to about 1.5 percent today. From the perspective of less developed countries, there is much to celebrate--increased survival and increased access to safe, effective contraception.
But fertility remains quite high in Africa and certain countries in other regions. Even in less-developed countries where the total fertility rate is less than 2.1 children per woman--the replacement level will in the long run lead to zero population growth--the sheer numbers of young people mean that considerable momentum for population growth remains. The United Nations projects that by 2050, world population will grow by almost three billion, and most of that growth will come from less-developed countries. Much of it will occur in cities--a frightening thought for anyone ever caught in a traffic jam in a third-world capital.
John Bongaarts, a vice president at the Population Council, has estimated that 49 percent of population growth in less developed countries during the 21st century will be due to this population momentum, 18 percent due to continued high demand for children, and 33 percent due to unwanted births--births that occur after the number of children desired by each couple has been reached. …