How much should we worry about global depopulation? In some East Asian countries fertility rates are near 1.0 or lower, with the vast majority of Europe’s major population declining. In the US, fertility rates fell below re-establishment rates, hitting a historic low of 1.7 in 2019 and falling further in 2020 due to the Kovid. The poorest countries in the world are dropping their birth rates at an unprecedented rate. By the year 2100, according to one projection, world population growth will be practically zero.
If you think the world is overpopulated and has serious environmental problems, you can welcome this news. As my colleague Robin Hanson points out, a declining population creates their own indescribable logic. If the Japanese population halves to 65 million, why not reduce it to 30 million? Or 20 million?
There is some evidence that a declining population is not bad for the world economy. For me, however, the greatest tragedy is the failure to make full use of the planet’s potential to sustain human life. No family policy should be mandatory. But there must be policies that make large families financially and otherwise more attractive to choose from.
One possibility is that the declining population will also bring about self-reversing policies. For example, the Japanese population would convert half of the current size of Japan into vacant land, possibly reducing land prices. Some families find it easier to buy a large apartment in central Tokyo and decide to have more children.
But that policy is likely to reduce rather than reverse population decline. Living space is one of the many factors behind decisions about family size. As the population declines, so does the stock of houses and apartments, so the amount of space for the family may not increase much in the long run.
Demographic trends depend on how permanent the causes of fertility decline are. In most cases women prefer to pursue a career, or start having children later, i.e. lower birth rates. The same logic applies in Japan or Italy, which have very small populations.
Another factor affecting fertility, especially in the US, is single parenthood. If a potential mother faces another full-time parenting decision in the scene, she is more likely to choose to have fewer children. As the population dwindles, will single-parent families become smaller? It’s hard to see why. The problem is the lack of unmarried men, unstable family rules or women who prefer to go it alone, there is no particular reason to think that those factors will disappear in an age of declining population.
If anything, the motivation towards small family size may continue or accelerate. Job opportunities for women may continue to improve quality, which increases the opportunity costs to have a large family. Furthermore, many countries in the world are becoming rich. As wealth increases, religiosity decreases, and religiosity also increases family size.
What are some other interfering factors to restore fertility? Perhaps soft and loving robots will make it much easier to raise young children. Or, when the population is falling to a very low level, moral panics arise. Families decide to have more children, thinking that the survival of their country is in danger. A more widespread and dystopian scenario is that corporations should take over vacant parts of the world and pay to raise children there, instead of a portion of their future income.
Undoubtedly there are other unusual (and more utopian) scenes. Whatever their probability, it is not wise to count them. Governments in many places, such as Singapore, have been aggressive but have resorted to useless family-friendly subsidy policies.
The world, and especially its wealthy nations, are also failing to negotiate, with very little address. In any year, in any country, a declining population may not be too much of a problem and it is welcome. But make no mistake: over time, collectively, we choose a very different future for humanity.