A substantial change in the composition of the world’s population has been observed, according to a new report published in the Lancet.

The results of the report show that there has been a remarkable global decline in the number of children that are being born, with the researchers saying that the findings are “a huge surprise”.

The study followed trends in every country of the globe from 1950 to 2017.

Particularly, in 1950, women were having an average of 4.7 children in their lifetime but by last year the fertility rate all but halved to 2.4 children per woman, but that masks huge variation between nations.

The fertility rate in Niger, west Africa, is 7.1, but in the Mediterranean island of Cyprus women are having one child, on average, while in the UK, the rate is 1.7, similar to most Western European countries.

Is there an ideal rate?

The total fertility rate is the average number of children that a woman will give birth to in her lifetime (it’s different to the birth rate, which is the number of children born per thousand people each year).

Whenever a country’s rate drops below approximately 2.1, populations will eventually start to shrink and there would be profound consequences for societies with “more grandparents than grandchildren”.

Which countries are more affected?

The countries with the lower fertility rates are the more economically developed countries including most of Europe, the US, South Korea and Australia. That does not mean that the population is falling, at least not yet as that depends on a mix of the fertility rate, death rate and migration. Moreover, it takes at least a generation for changes in fertility rate to take hold.

But Prof Christopher Murray, the director of the Institute for Health Metrics and Evaluation at the University of Washington, told the BBC that “we will soon be transitioning to a point where societies are grappling with a declining population”.

He added that “we’ve reached this watershed where half of countries have fertility rates below the replacement level, so if nothing happens the populations will decline in those countries.

“It’s a remarkable transition.

Why is the fertility rate falling?

The reason for the fall in fertility rate has nothing to do with sperm counts or any of the things that normally come to mind.

Instead it is being put down to three factors:

-Fewer deaths in childhood meaning women have fewer babies
-Greater access to contraception
-More women in education and work

What will the impact be?

Without migration, countries will face ageing and shrinking populations.

Dr George Leeson, director of the Oxford Institute of Population Ageing, says that this possibility is not necessarily a bad thing, as long as the society will adjust to the massive demographic change.

As he said to the BBC: “Demography impacts on every single aspect of our lives, just look out of your window at the people on the streets, the houses, the traffic, the consumption, it is all driven by demography.

“Everything we plan for is not just driven by the numbers in the population, but also the age structure and that is changing, so fundamentally we haven’t got our heads around it”, he added

Leeson thinks that workplaces will have to change and even the idea of retiring at 68, the current maximum in the UK, will be unsustainable.

Report author Prof Murray stresses: “On current trends there will be very few children and lots of people over the age of 65 and that’s very difficult to sustain global society.

“Think of all the profound social and economic consequences of a society structured like that with more grandparents than grandchildren”, he concludes.

China rates

A country that has seen a huge population growth since 1950 is China, going from around half a billion inhabitants to 1.4 billion.

But the country is also facing the challenge of fertility rates, which has increased to 1.5 in 2017, and moving away from its famous one child policy.

The reason that developed countries need a fertility rate of 2.1 is because not all of the children survive to adulthood, while babies are slightly more likely to be male than female.

In China, the report shows that for every 100 baby girls there were 117 boys, which “imply very substantial sex-selective abortion and even the possibility of female infanticide”.

That means that even more children need to be born to have a stable population.

The impacts

 

Source: The Lancet