The World’s Peak Population May Be Smaller Than Expected

“I have ten children,” says Rahama Sa’ad squatting outside her shack on the outskirts of Kano, the biggest city in northern Nigeria. “It’s the will of God,” she explains, as chickens, children and grandchildren scramble around her. In northern Nigeria big families are easy to find. Abdulkadar Dutse, a local businessman in Kano, is one of 35 siblings split among the four wives of his father.

Such stories of big families inform much of how the world thinks about sub-Saharan Africa, not just now but over coming decades. At conferences and in cabinet meetings across the continent, politicians and policymakers fret about how to educate, employ, house and feed a population that the un expects to grow at breakneck speed from around 1.2bn people now, to 3.4bn people by 2100. In southern Europe, populists stoke up fears that hundreds of millions of Africans may try to cross the Mediterranean to escape poverty, war or hunger. Across the rich world, environmentalists fear the impact on the climate and planet of an extra 2bn people.

Yet few have noticed a wealth of new data that suggest that Africa’s birth rate is falling far more quickly than expected. Though plenty of growth is still baked in, this could have a huge impact on Africa’s total population by 2100. It could also provide a big boost to the continent’s economic development. “We have been underestimating what is happening in terms of fertility change in Africa,” says Jose Rimon II of Johns Hopkins University. “Africa will probably undergo the same kind of rapid changes as east Asia did.”

The un’s population projections are widely seen as the most authoritative. Its latest report, published last year, contained considerably lower estimates for sub-Saharan Africa than those of a decade ago. For Nigeria, which has Africa’s biggest population numbering about 213m people, the un has reduced its forecast for 2060 by more than 100m people (down to around 429m). By 2100 it expects the country to have about 550m people, more than 350m fewer than it reckoned a decade ago.

Yet even the un’s latest projections may not be keeping pace with the rapid decline in fertility rates (the average number of children that women are expected to have) that some striking recent studies show. Most remarkable is Nigeria, where a un-backed survey in 2021 found the fertility rate had fallen to 4.6 from 5.8 just five years earlier. This figure seems to be broadly confirmed by another survey, this time backed by usaid, America’s aid agency, which found a fertility rate of 4.8 in 2021, down from 6.1 in 2010. “Something is happening,” muses Argentina Matavel of the un Population Fund.

If these findings are correct they would suggest that birth rates are falling at a similar pace to those in some parts of Asia, when that region saw its own population growth rates slow sharply in a process often known as a demographic transition.

A similar trend seems to be emerging in parts of the Sahel, which still has some of Africa’s highest fertility rates, and coastal west Africa. In Mali, for instance, the fertility rate fell from 6.3 to a still high 5.7 in six years. Senegal’s, at 3.9 in 2021, equates to one fewer baby per woman than little over a decade ago. So too in the Gambia, where the rate plunged from 5.6 in 2013 to 4.4 in 2020, and Ghana, where it fell from 4.2 to 3.8 in just three years.

These declines bring west Africa closer to the lower fertility rates seen in much of southern Africa. Dropping rates have already been celebrated in places such as Ethiopia and Kenya (see chart).

Demographers are divided over how much to read into these recent surveys, particularly since the data they produce can be noisy. ”When you see a precipitous decline in fertility, your starting-point is that something is wrong with the data,” says Tom Moultrie of the University of Cape Town. Some point out that survey responses in Africa on desired family size have fallen little, though not all recent surveys ask that question. Other demographers reckon the data point to real changes. Still, many caution against comparing rates across different sorts of polls. Yet even comparing only within iterations of the same survey (as The Economist has done with the figures above), the trend is evident. Comparing across them in the case of Niger, which has the world’s highest fertility rate but few surveys, shows a decline from 7.6 in 2012 to 6.2 in 2021.

Others are also reducing their projections. In 1972 the Club of Rome, a think-tank, published an influential book, “The Limits to Growth”, warning that consumption and population growth would lead to economic collapse. Now it says the population bomb may never go off: it reckons sub-Saharan Africa’s population may peak as soon as 2060, which is 40 years earlier than the un’s projections.

Even so, fertility rates are not dipping uniformly. Some countries, including Angola, Cameroon and Congo, are seemingly stuck at relatively high rates. And there are often big regional differences within countries such as Kenya. Almost everywhere in Africa, fertility rates are much lower for urban women, who typically have 30-40% fewer children than those in the countryside.

Demographers would be more inclined to agree that these fertility declines are real and likely to continue if they could easily identify their causes. In Ethiopia, Kenya and Malawi, past plunges have been strongly associated with higher use of contraception, often thanks to big government pushes. In Malawi and Kenya well over half of married women use modern contraception such as the pill or injectables, while in Ethiopia about 40% do. The use of such methods is markedly lower in west Africa (see map), but improvements from a low base are probably part of the reason for the fertility drops. In Nigeria contraception use has gone from 11% to 18% in the past five years. In Senegal it has doubled to 26% in the past decade.

Family planning, especially when promoted by outsiders, has often caught the ire of religious leaders. Yet in some places that may be changing. Clerics talk more often about family planning these days, notes Amina Mohammed, a devout mother on the outskirts of Kano. “There is no verse in the Holy Koran where Muslims are forbidden from controlling, planning or restricting the number of children they have,” says Shuaib Mukhtar Shuaib, one such cleric. The Prophet Muhammad tacitly approved of the withdrawal method, he continues. {snip}

{snip}