In the 2nd century AD, the theologist Tertullian issued a warning that could have come from an Extinction Rebellion pamphlet. Humanity’s growing numbers had become “too burdensome”, he fretted, “the elements scarcely suffice for our support”. The only solution, he feared, was to “prune the overgrowth” via pestilence, famine and war.
Given that Tertullian’s home city of Carthage was among the world’s largest at the time, his jitters were perhaps understandable. However, at roughly 500,000, Carthage was still barely the size of modern-day Edinburgh. And courtesy of “pruning” by events such as the Black Death and the Thirty Years’ War, the world’s population did not grow that much until the Industrial Revolution, 1,500 years later.
Yet as the demographer Paul Morland points out in Tomorrow’s People, Tertullian was merely kick-starting a long tradition of population pessimism – most famously upheld by the economist Thomas Malthus, who wrongly feared that humanity’s capacity to multiply would outstrip its capacity to feed itself. So here, first of all, is Morland’s good news.
Despite the world’s population being nearly eight billion, it is likely to peak this century at around 11 billion, as better life expectancy and living standards in the developing world reduce the need for large families. Climate change catastrophes notwithstanding, he says, that figure can be sustainable.
What is less reassuring is that while some countries’ populations may go up, others may die out altogether. Take Japan – now nicknamed the “land of the setting sun”, because its ageing population is expected to shrink by a fifth over the next half-century.
Not enough young Japanese want to have children, nor is Japan keen to admit migrants, meaning the once-crowded suburbs of Tokyo could become “mini-Detroits”. Western nations have the same problem, especially more conservative countries such as Italy, where women are still discouraged from juggling a career with children. Faced with that binary choice, Morland says, many opt for “an interesting job rather than motherhood”. He notes: “Just as there are no more Visigoths, there is no guarantee that there will be any Italians or Japanese.”
Facing the opposite challenge is much of sub-Saharan Africa, where a population boom caused by falling child mortality has not yet been offset by a reduction to the two-child family model now common elsewhere. By 2100, the region will account for one in three people in the world (compared with one in 14 in 1950).
Yet even now, the likes of Nigeria, whose population is expected to double to 400 million by 2050, has nothing like enough jobs to go round. With Europe tightening its borders to African migration, the continent will need an “extraordinary feat of human development” to avoid conflict and chaos.
Morland is illuminating on how the ebbs and flows of population can influence history. Individuals may start wars and revolutions, but sheer force of numbers adds an underlying seismic pressure. Russia’s rapid birth rate at the turn of the last century, for example, was one reason that Germany viewed it as such a threat.
By the 1960s, though, Russians were having fewer children than most Western nations, thus speeding the Soviet Union’s decline. Today, Russia’s population is shrinking like Japan’s, thanks partly to appalling male alcoholism rates.
Youthful societies are often turbulent, thanks to the numbers of young, childless males with little to lose. This, Morland says, was a common factor in many of the world’s great upheavals, from the Bolshevik revolutions to the Arab Spring. By contrast, the terror campaigns in Northern Ireland and Spain’s Basque region ended partly because ageing populations had “sapped the energy” from the conflicts.
Morland’s book is a concise chronicle of our global breeding habits, as deft with social context as it is with figures. Given how climate change concerns have politicised the issue of population, it’s very topical. The Duke of Sussex, for example, has said he will have no more than two children.
The more radical eco-activists of the so-called “birth-striker” movement plan to have none at all. Indeed, as Morland notes: “The worry is that eventually the human race will be at risk of disappearing altogether.” On that point, we may have to hope that, just like Malthus and Tertullian before him, Morland turns out to be wrong.
Tomorrow’s People by Paul Morland is published by Picador at £20. To order your copy call 0844 871 1514 or visit the Telegraph Bookshop
