Population

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 fastest growth period occurred from 1974 to 2011, taking only 12 to 13 years to increase by one billion for the 5th, 6th, and 7th.

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: 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 the doubling time alongside it. In this visualization, 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.