A study published in the Lancet shows that in half the countries of the world there has been a remarkable decline in the number of children women are having, which means that in over half the countries of the world, particularly in economically developed countries (Europe, the US, South Korea and Australia) there are insufficient children to maintain population size. In many societies there are more grandparents than grandchildren.
In 1950, women were having an average of 4.7 children in their lifetime. Last year the fertility rate had all but halved to 2.4 children per woman. There is a huge variation between nations: in Niger, the birth rate is 7.1, while in Cyprus women are having one child, on average. In the UK, the rate is 1.7, similar to most Western European countries.
As for China, since 1950, the Chinese population has increased from around half a billion inhabitants to 1.4 billion, and is also facing lower fertility rates (only 1.5 in 2017). It has recently moved away from its famous one child policy. For
every 100 Chinese girls born there were 117 boys which “implies substantial sex-selective abortion and even the possibility of female infanticide”. This means even more children need to be born to have a stable population.
Whenever a country’s average fertility rate drops below approximately 2.1 populations will eventually start to shrink. This does not mean the number of people living in these countries is falling, at least not yet, as the size of a population is a mix of the fertility rate, death rate and migration. Half the world’s nations are still producing enough children to grow, but as more countries advance economically, more will have lower fertility rates.
The fall in fertility rate is not down to sperm counts or any of the things that normally come to mind when thinking of fertility. Instead it is being put down to three key factors:
Fewer deaths in childhood, meaning women have fewer babies
Greater access to contraception
More women in education and work
The answer? Without migration, countries will face ageing and shrinking populations, which might not be so bad as long as society can adjust to it. For instance, the idea of retiring at 68, the current maximum in the UK, will be unsustainable and will have to change. Another possibility is encouraging women to have more children, although this has not been historically very successful (Italy, for instance). On the plus side a smaller population would benefit the environment.
(Based on a World Health Organisation report called “Global Burden of Diseases” that has been running since the 1990s)