Harry and Meghan are talking nonsense: we’ll soon be fretting about depopulation

The timing was unfortunate. The day after the Duke and Duchess of Sussex let it be known that, for environmental reasons, they would have no more than two children, the Office for National Statistics revealed that the birth rate in England and Wales had plummeted by 10 per cent since 2010. In order to remain the same size, a population needs 2.1 live births per woman. In England and Wales, that number has fallen to 1.7, down from 1.8 the previous year.

There is a perception lag when it comes to human population. Most people believe that the world is being choked by the viral spread of our species. Green politicians openly tell us that having children is a selfish act. You can spend an entire lifetime, they

say, avoiding flights and car journeys, meticulously reusing and recycling, growing your own vegetables; but have one kid and all that conscientious behaviour is wiped out.

Yet the counter-intuitive truth is that we are heading, sooner or later, for depopulation. Demographers disagree about when it will come, but almost all accept that it will happen during this century. A major study by Deutsche Bank suggests that the global population will reach 8.7billion in 2055, before dropping back to 8billion by the end of the century. The United Nations thinks the peak will be 11.5billion – though it has a long history of overestimating population growth. Some outlying studies claim as much as 14billion. But all agree that a peak is coming.

Why? Because, in every country, fertility drops as wealth rises. Again, statisticians argue about why this happens. We seem to be unique, as a species, in becoming less fecund as the food supply increases. Some aver that the key link is with female education: the more years girls get in school, the lower the birth rate. Others believe that the more important factor is the rise of a consumer society. One study shows a correlation between the decline in fertility and the spread of television, presumably because couples have alternative ways to spend their evenings.

My own hunch is that the key correlation is with infant mortality. In a society where many children will perish from disease, malnutrition or violence, it makes sense to have a large family. As the rule of law and modern medicine spread, the incentives alter. But there is always a hiatus, a transitional generation that retains the cultural habits of large families as infant mortality falls. This is what causes the population bulge. It happened in Europe and North America in the 19th century, in Latin America and East Asia in the 20th. It is happening in India, the Middle East and Africa now.

We can argue about the causes, but not the numbers. On every continent, economic development is squeezing fertility. The rate of reproduction in Kenya has fallen over the past 50 years from eight live births per woman to 3.5. In Iran, the decline is from 6.8 to 2.1; in Brazil, from 5.7 to 1.7. The wealthier the country, the deeper the drop.

Can you remember the first words that God addresses to the human race? That’s right. “Be fruitful and multiply” (Genesis 1:28). Now why would the Almighty need to tell us to breed? Because, at that time, we were in Eden. Why, in a world of perfect leisure and pleasure, would anyone bother with children?

Today, in rich countries, most of us live as if in Eden, enjoying distractions and luxuries beyond the imagination of previous generations. Sure enough, the birth rate in developed states is far below replacement level: Chile 1.7, Germany 1.6, Canada 1.5, Luxembourg 1.4, Japan 1.3, Singapore 1.2, South Korea 1.1.

Even those figures are often pushed up by immigrant mothers, who retain the cultural habits of poorer societies. One in three babies in Britain is born to a woman from overseas.

There are plenty of arguments against having children. No one should feel pressured one way or the other. But it no longer makes sense to present small families as a wholly altruistic choice.

The challenges the next generation will face have to do with depopulation: unfunded pensions, decaying towns and intergenerational tensions. God may have been on to something.