The great defining event of the 21st century — one of the great defining events in human history — will occur in three decades, give or take, when the global population starts to decline. Once that decline begins, it will never end. We do not face the challenge of a population bomb, so rampant in the popular imagination, but of a population bust — a relentless, generation-after-generation culling of the human herd. Nothing like this has ever happened before.
If you find this news shocking, that’s not surprising. The United Nations forecasts that our population will grow from 7 billion to 11 billion in this century before leveling off after 2100. But an increasing number of demographers around the world believe the UN estimates are far too high.
More likely, they say, the planet’s population will peak at around 9 billion sometime between 2040 and 2060 and then start to decline. By the end of this century, we could be back to where we are right now and steadily growing fewer.
The demographic transition model, which was first developed in 1929, used to contain only four stages. Stage four, the final stage, envisioned a world in which life expectancy was high and the fertility rate was low, around the level needed to sustain the population: 2.1 babies per mother (one per mother, one per father, and an extra 0.1 to account for children who die in infancy and women who die before childbearing age). But as it turned out, there is a fifth stage: one in which life expectancy continues to slowly increase, even as fertility rates continue to decline below the replacement rate, eventually leading to a declining population. Just about the entire developed world is in stage five.
Darrell Bricker & John Ibbitson
Taking a break from the urgent issues of today, here’s a worldwide trend that will certainly reshape our societies in the coming century: the upcoming shift from the population growth we experienced since the dawn of civilization to a stagnating and shrinking population. There were of course numerous dips in various regions in times of famine and plague, but the overall trend was ascending owing to a high birth rate. Modern science and civilization have reversed both fundamentals: better healthcare has decreased child mortality and increased life expectancy, while increased urbanization, education and secularism have reduced previous pressures to have as many children as possible.