# How has world population growth changed over time?

## The world population has increased rapidly in recent centuries. But this is slowing.

The world population has changed in dramatic ways over the last few centuries. Let’s take a look at long-run data on population to understand this change, and how quickly the world population is growing today.

The chart shows the increasing number of people living on our planet over the last 12,000 years. A mind-boggling change: the world population today is around 2,000 times the size of what it was 12,000 ago when the world population was around 4 million – less than half of the current population of London.

What is striking about this chart is of course that almost all of this growth happened just very recently. Historical demographers estimate that around the year 1800 the world population was only around 1 billion people. This implies that on average the population grew very slowly over this long time from 10,000 BCE to 1700 (by 0.04% annually). After 1800 this changed fundamentally: the world population was around 1 billion in the year 1800 and is now, at around 8 billion, 8 times larger.

Around 108 billion people have ever lived on our planet. This means that today’s population size makes up 6.5% of the total number of people ever born.^{1}

For the long period from the appearance of modern Homo sapiens up to the starting point of this chart in 10,000 BCE it is estimated that the total world population was often well under one million.^{2} In this period our species was often seriously threatened by extinction.^{3}

You can explore the interactive visualization of this change.

## How has the world population growth rate changed?

We looked at the absolute change in the global population over time. But what about the rate of population growth?

The global population growth rate peaked long ago. The chart shows that global population growth reached a peak in 1962 and 1963 with an annual growth rate of 2.2%; but since then, world population growth has halved.^{4}

For the last half-century we have lived in a world in which the population growth rate has been declining. The UN projects that this decline will continue in the coming decades.

A common question we’re asked is: is the global population growing exponentially? The answer is no.

For population growth to be exponential, the growth rate would have be the same over time (e.g. 2% growth every year). In absolute terms, this would result in an exponential increase in the number of people. That’s because we’d be multiplying an ever-larger number of people by the same 2%. 2% of the population this year would be larger than 2% last year, and so on; this means the population would grow exponentially.

But, as we see in this chart, since the 1960s the growth rate has been falling. This means the world population is not growing exponentially.

## Other ways to visualize population growth

### How long did it take for the world population to double?

There are few other ways to contextualize this period of population growth.

In this chart we show the time it took the world population to double. On the y-axis we have the number of years to double; on the x-axis we have the year that a population level was reached. Hover over each point to see the population change (for example, from 0.5 to 1 billion).

In the past the population grew slowly: it took nearly seven centuries for the population to double from 0.25 billion (in the early 9th century) to 0.5 billion in the middle of the 16th century. As the growth rate slowly climbed, the population doubling time fell but remained in the order of centuries into the first half of the 20th century. Things sped up considerably in the middle of the 20th century.

The fastest doubling of the world population happened between 1950 and 1987: a doubling from 2.5 to 5 billion people in just 37 years — the population doubled within a little more than one generation. This period was marked by a peak population growth of 2.1% in 1962.

Since then, population growth has been slowing, and along with it the doubling time. In this visualisation we have used the UN projections to show how the doubling time is projected to change until the end of this century. By the 2080s, it will once again have taken approximately 100 years for the population to double to a predicted 10.4 billion.

### How long did it take for the world population to increase by one billion?

This visualization provides an additional perspective on population growth: the number of years it took to add one billion to the global population. This is based on the 2022 revision of world population estimates from the UN Population Division.

This visualization shows again how the population growth rate has changed dramatically over time.

It wasn’t until 1805 that the world reached its first billion; it then took another 120 years to reach two billion. By the third billion, this period had reduced to 35 years, reduced further to 14 years to reach four. The period of fastest growth occurred from 1974 to 2011, taking only 12 to 13 years to increase by one billion for the 5th, 6th, and 7th.

The world has now surpassed this peak rate of growth, and the period between each billion is expected to continue to rise. It’s estimated to take approximately 14 years to reach nine billion in 2024, and a further 21 years to reach 10 billion in 2058.

The latest UN medium projection expects that the world will not reach 11 billion people this century: it projects the population to peak at 10.4 billion in 2086 before falling again.

### Endnotes

As per 2011 estimates from Carl Haub (2011), “How Many People Have Ever Lived on Earth?” Population Reference Bureau.

See for example Kremer (1993) – Population growth and technological change: one million BC to 1990. In the Quarterly Journal of Economics, Vol. 108, No. 3, 681-716.

John Hawks, Keith Hunley, Sang-Hee Lee, Milford Wolpoff; Population Bottlenecks and Pleistocene Human Evolution, Molecular Biology and Evolution, Volume 17, Issue 1, 1 January 2000, Pages 2–22.

This data comes from the UN World Population Division.

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`Max Roser and Hannah Ritchie (2023) - "How has world population growth changed over time?". Published online at OurWorldInData.org. Retrieved from: 'https://ourworldindata.org/population-growth-over-time' [Online Resource]`

BibTeX citation

```
@article{owid-population-growth-over-time,
author = {Max Roser and Hannah Ritchie},
title = {How has world population growth changed over time?},
journal = {Our World in Data},
year = {2023},
note = {https://ourworldindata.org/population-growth-over-time}
}
```

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