Population Matters

Not Written in Stone: Projections and Pledges

October 5th, 2010

Many bright and otherwise well-informed people believe that population growth is a fait accompli.  They accept without much thought or reservation the U.N. projection indicating that world population will grow to 9.1 billion by 2050.  Few understand that the U.N.’s projection is just a medium variant, and that U.N. demographers also issued  ‘low’ and ‘high’ variants showing population growing somewhere between 8 billion and 11 billion by mid-century.

August Comte, the French sociologist, once famously declared that “demography is destiny,” but he never said it was predestined.  Fertility and mortality rates can easily defy projections. That’s why projections are not written in stone; they are frequently updated to take into account new data. Demographic projections, as demographers are found of saying, are not predictions. 

God and academia forbid that a demographer should ever make a prediction, but demographers can be so bold as to discuss the potential impact of fertility shifts.  Joseph Chamie, former director of the United Nations Population, wrote a piece (The Battle of the Billionaires:  China vs. India”) for the Globalist yesterday that offers some interesting insights into the demographic future of the world’s two most populous countries.  He notes that according to the U.N.’s medium variant projection:

India’s rapidly growing population is projected to reach 1.61 billion by mid-century, an increase of 400 million people over the next four decades.

In contrast, China’s population is expected to peak around the year 2032 at 1.46 billion — an increase of 110 million — and then begin to decline slowly.

But then he observes that:

Of course, other demographic outcomes are possible. One less likely, but nonetheless instructive, scenario assumes that the current fertility rates of China and India remain constant over the next four decades.

In such a case, by mid-century India’s population soars to 2 billion and China’s population is declining by 6 million annually, having peaked at 1.45 billion in 2030. In addition, India becomes more populous than China even earlier, in a little more than a decade.

 Another intriguing scenario assumes that China changes its one-child policy to a two-child policy, with its fertility soon rising to somewhat above replacement, i.e., 2.35 children per woman, and India’s fertility declines gradually to this same fertility level as China.

 In this instance, the populations of both China and India would be substantially larger by mid-century, 1.62 and 1.87 billion, respectively — together gaining an additional billion people.

Chamie doesn’t discuss how differing fertility assumptions might affect population growth projections for other countries, but the same principle applies.  The U.N.’s medium variant assumes that birth rates in developing countries with high fertility will continue to decline.  If they do not fall fast enough, population growth could easily surpass the official projections, particularly in sub-Saharan Africa and parts of South Asia.  Much depends on the level of support for international family planning and the commitments of the developing nations themselves. 

The pledges made at the MDG summit last month offer some ground for renewed optimism.  Australia, the U.K., the U.S., and the Gates Foundation unveiled a new public/private partnership aimed, among other things, at expanding family planning services to another 100 million women by 2015.  If fulfilled, these pledges could go a long way toward realizing the goal of universal access to family planning and reproductive health services. They might also lower official population projections. 

 But pledges, like projections, are not written in stone.  

Posted by Robert J. Walker, Executive Vice President

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