Experts predict ‘jaw-dropping’ fertility crash

Granny boom: 2100 could see twice as many people over the age of 80 than under the age of five.

Is this a good thing? Scientists say we have greatly overestimated population growth. While environmentalists might be happy, a lack of young people could also lead to terrible consequences.

In the 2006 film Children of Men, the world is devastated by plagues. The UK has become a prison state, regularly executing immigrants. The future of humanity is at stake. No child has been born for 18 years.

A far-flung fiction? Not so, says new, extensive, and eye-opening research.

Experts found that the world population is likely to peak at around 9.7 billion people in 2064, before falling to 8.8 billion in 2100.

“These forecasts suggest good news for the environment, with less stress on food production systems and lower carbon emissions,” said the University of Washington’s Christopher Murray, who led the study.

Previous models had predicted that the world’s population would continue to increase throughout the 21st Century. But, as societies modernise and women are empowered to live their own lives, fertility rates drop sharply.

Maintaining population levels requires 2.1 children per household. However, “as women become more educated and have access to reproductive health services, they choose to have less than 1.5 children on average,” said Murray.

This means that 183 out of 195 countries studied will be shrinking by the end of the century. Without major shifts in behaviour or mass immigration, major economies like China, Japan, Spain, and Poland could all see their populations halve.

Sub-Saharan Africa will buck the trend and benefit from great economic opportunity, with Nigeria set to become the world’s second-most populous nation (after India), with its population rocketing to 800 million. This will cause “radical shifts in geopolitical power”, says Lancet editor Richard Horton, who published the study.

For most of the world, there will be a huge swing towards older populations. Ageing societies, while typically more peaceful, are not thought to be particularly desirable. Throughout history, the most prosperous and powerful nations have been those rich in young people.

When population pyramids are flipped onto their heads – with the old outnumbering the young – the most important question becomes: who will make the money? One answer is immigrants. As UCL’s Professor Ibrahim Abubaka told the BBC: “The distribution of working-age populations will be crucial to whether humanity prospers or withers.”

For other thinkers, a shrinking population can only be a good thing. In 1798, Thomas Malthus described how humanity was condemned to outgrowing Earth’s resources and living in eternal misery. Martin Luther King referred to “the modern plague of overpopulation”, while Mikhail Gorbachev suggested that “the ecological crisis, in short, is the population crisis”.

So, is this “fertility crash” a good thing?

Empty streets

Yes. It is good news for the environment. Once this happens, the whole world will be in a position to control its own destiny. As the late Hans Rosling put it, any further growth in population becomes a question of “love” not necessity.

No. For thousands of years, the young have outnumbered the old. Reversing this trend could have terrible consequences. Economies could collapse without enough workers. Societies run by old people could become highly risk-averse and backward looking. Cultural life and entertainment could stagnate. It would be awful!

You Decide

  1. Considering how much of Earth is uninhabited, do you think there really is a natural limit to the global population?
  2. Do you think that governments should ever get involved in how many children people have?


  1. If your country was run by people over 80, what changes would there be? Make a list of three new laws you think they might pass.
  2. Using the data in the Expert Links, sketch a rough map of the world in which countries are sized according to their population in 2100. (So, India would be the biggest country on your map.)

Some People Say...

“Instead of controlling the environment for the benefit of the population, perhaps it is time we controlled the population to allow the survival of the environment.”

David Attenborough, British broadcaster and natural historian

What do you think?

Q & A

What do we know?
There are 7.7 billion people in the world today. According to the new research, more than 20 countries will see their population numbers diminish by at least 50% over the next 80 years. Sub-Saharan Africa, meanwhile, will triple in size to around three billion people.
What do we not know?
How countries will look to reverse their shrinking populations. “There is a very real danger that some countries might consider policies that restrict access to reproductive health services, with potentially devastating consequences,” said Christopher Murray. We also do not know how other factors, such as Covid-19 and the climate crisis, might affect these figures.

Word Watch

Fertility rates
The number of children born, on average, to each woman within a studied group. A total fertility rate of 2.1, is the minimum needed for a population to remain steady and is known as the “replacement rate”.
Reproductive health services
Resources provided to young people, especially women, to limit the chances of unwanted pregnancies. These include contraceptive pills, condoms, and access to abortion.
Population pyramids
A population pyramid, also called an “age-gender-pyramid”, is a graphical illustration that shows the distribution of various age groups in a population (with the youngest at the bottom). This forms the shape of a pyramid when the population is growing.
Thomas Malthus
English cleric and economist (1766-1834). Malthusianism is the idea that human population grows faster than its resources – and often implies a belief that population numbers should be limited in some way.
Hans Rosling
Swedish physician, academic, and public speaker (1948-2017).
Stop developing; become inactive or dull. Usually to describe water or air, when it ceases to flow or move.


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