The Problem With the UN’s New Fertility Forecasts
The UN has reversed a decade of speculation about a demographic winter in the West, and now says that every country will achieve replacement fertility by 2100 resulting in a global population of 10 billion. The problem is there is no basis for their turnabout.
UN agencies are hailing new numbers as evidence of overpopulation in the developing world and vindication of decades of anti-natal policies in the West, but the scientific basis of the latest UN forecasts is slim.
The most significant change in the UN’s new numbers is an increase in the predicted convergence rate from 1.85 children per woman, below replacement, to 2.1, about replacement fertility.
While the UN claims there is consensus on the matter, demographers have long argued that there is no evidence to support the assumption that global fertility will ever converge, and no basis for the assertion that all nations go through three phases of demographic change: from declining birth rates where most developing nations are today, to below replacement rates experienced by all developed countries except the US, and finally to recovery at near replacement rates which a few Northern European countries have achieved.
Adherents to the recovery hypothesis say that the dip in European fertility rates may be due to women’s delaying childbearing. But as a new RAND study points out, “changes in birth timing can affect short-term birthrates” but “the effects are mild, and the result of delay can be permanent for the population as a whole even if not permanent for any one woman.”
In terms of youth 15-24 years old entering the workforce or military, the new figures would mean that India’s much-anticipated demographic advantage over China would be curtailed. India would have 75 million fewer youth by 2050, and 324 million fewer by 2100, while China would gain 26 million more than previously expected.
Germany’s share of youth in 2050 would rise from a projected 8.5 percent to 10 percent of its population according to the new UN forecast, more than doubling the number of youth previously predicted by 2100. Likewise, the number of Russian youth would be more than twice existing projections, and Japan’s share of youth would jump from just 7.7 percent in 2050 to 10.4 percent in 2100.
In sharp contrast, governments remain pessimistic. Recent reports from the European Commission and the Japanese government, for example, assume that fertility will remain near today’s levels which are about 1.3 in Japan, and 1.4 in Germany.
To achieve the dramatically new fertility predictions, the UN Population Division created a “probabilistic model” that uses high capacity computing to run 100,000 of fertility scenarios for each country.
While this new model gives a patina of greater scientific accuracy, it is based upon an arbitrary and unsubstantiated fertility rate. Just because demographers now have the capability of churning out many thousands of scenarios for each country studied does not mean the result is scientific.
Policy analysts would do well to reject the UN one-size-fits-all fertility projections and rely instead on data accounting for the various national factors contributing to desired family size.
