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The world's population is increasing every year, creating an overcrowded planet--isn't it? For some time, demographers have considered overpopulation a serious threat: it was the predictable focus of the twenty-third General Population Conference of the International Union for the Scientific Study of Population, held in Beijing last October. But what if, in fact, human population is imploding--not from some environmental catastrophe, but merely as a consequence of our own disinterest in reproduction?
Recently, at the United Nations, some of the world's top demographers have begun to consider this "low-fertility" or depopulation scenario. The UN's 1996 revision of its biennial compendium, World Population Prospects, a long-range study begun in 1950 to project possible demographic trends, outlines the new concepts. Nicholas Eberstadt '76, M.P.A. '79, a researcher at the School of Public Health's Center for Population and Development Studies, has also worked with the low-fertility scenario, which he calls "the neglected possibility." He recently described its implications in The Public Interest.
Initially, the idea seems to counter all we have been told. To begin with, there is no question that global population has been rising. Between 1985 and 1995, UN estimates indicate an increase of 840 million--from 4.85 billion to 5.69 billion. And projections suggest continued growth, to 6.09 billion in the year 2000.
But what the twenty-first century will bring depends on whether you subscribe to a high-, medium-, or low-fertility scenario. At the moment, the world "total fertility rate" (births per woman per lifetime) is thought to average just over 3.0. The high-fertility model, which envisions a global total fertility rate of 2.6 by the middle of the next century, would keep the figures growing perpetually; humanity would number 11.2 billion by 2050 and keep going up from there (see graph). The medium-fertility model suggests that the fertility rate will fall to the "replacement" level (2.1 births per woman)--and thus level off--by 2050, when the population would be 9.37 billion. In contrast, the low-fertility model (1.6 births per woman) pegs the population total at 7.66 billion in 2050--down by nearly 90 million from a projected peak of 7.75 billion in 2040.
How could this happen? Eberstadt points out that the world's fertility level has never been as low as it is today. The low-fertility model projects a future based on the continuation of these existing declines. By the UN's estimates, total fertility rates in the more developed countries have fallen since the early 1990s from 1.7 to 1.5 births per woman of childbearing age. A modest continuation of this trend would bring the rate down to 1.4 in another decade. In less developed regions, fertility rates might fall from 3.3 in the 1990s to about 2.0 by the year 2020, and by 2050 drop to 1.6. For the least developed regions (mostly sub-Saharan Africa), a total fertility rate that now averages slightly over 5.0 would fall to less than 3.0 by 2020, and go below 2.0 by 2050. Collectively, these projections suggest the beginning of a global depopulation in less than half a century--albeit in a world more populous than today's.
Eberstadt, who is also a researcher at the American Enterprise Institute in Washington, D.C., emphasizes that this demographic projection is "not a prediction, but a possibility." Forecasting long-range fertility trends is challenging: "It is simply impossible," he quips, "to predict how many children will have children."
The low-fertility model also projects rising world life expectancies between now and the year 2050: from 75 to 81 years in more developed regions, from 64 to 76 in less developed regions; and from 52 to 72 in the least developed regions.
If these two demographic trends play themselves out as the low-fertility model suggests, their economic and cultural impact on society could be drastic. While the number of children would decline, the elderly population would boom. In developed countries this could severely strain some current pension programs, which were established during times of relatively high fertility and rapid population growth. "With below-replacement fertility and increasing longevity," writes Eberstadt, "the arithmetic of these schemes changes unforgivingly."
He also considers the possible impact on family life. In the low-fertility scenario, Eberstadt laments that younger generations would have fewer "collateral blood relatives"--siblings, uncles, aunts--leaving only their parents and grandparents to "play with, learn from, love unthinkingly, and fight with ferociously." This social atomization concerns Eberstadt, who reflects that such a world "seems like kind of a lonely place."
~ Dan Boyne
