How World Population Grew Through History
From one million cave dwellers to eight billion people — and the two big question marks
Step through the growth of the world population, from one million people to eight billion.
About 50,000 years ago the whole world held roughly one million people. Man was a wanderer who sheltered in caves, killed animals and ate them raw or roasted, caught fish and gathered fruits, roots and leaves; his tools were made of stone, stick and bone.
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What this lesson covers
What you do
- Count how long each billion took: 123 years for the second, 33 for the third, only 14 for the fourth.
- Notice that the twentieth century raised the population by lowering the death rate, not by raising the birth rate.
Challenges to clear
- Walk the whole curve from one million people to eight billion.
- Reach the century in which medicine, not birth, did most to raise the population.
The task
Step through the growth of the world population, from one million people to eight billion.
What this lesson covers
- 50,000 years ago — 1 million — About 50,000 years ago the whole world held roughly one million people. Man was a wanderer who sheltered in caves, killed animals and ate them raw or roasted, caught fish and gathered fruits, roots and leaves; his tools were made of stone, stick and bone.
- The tool-making revolution — Improving those stone tools was the first of the three great cultural revolutions. Living in groups and hunting large animals such as mammoths made food more certain, and the population began to climb.
- 10,000 years ago — 5.3 million — By 10,000 years ago the world population had reached about 5.3 million. People settled in primitive huts, domesticated animals with the dog first of all, learnt to sow crops and store food in the agricultural revolution, and replaced stone tools with bronze and iron in the metal age.
- Seventeenth century — science and industry — The scientific and industrial revolution brought jobs, comfort and more food, and the population rose again. It had one drawback: crowding together caused widespread outbreaks of infectious disease, and unbalanced diets brought nutritional disease.
- Twentieth century — medicine — Antibiotics and prophylactic vaccination cut deaths sharply in all age groups, especially infants and the old. More children per family reached the reproductive age, and when they reproduced the growth rate rose very rapidly.
- 1804 to 1974 — the first four billion — World population reached 1 billion in 1804, 2 billion in 1927, 3 billion in 1960 and 4 billion in 1974. The annual growth rate had been below 1% before 1800 and peaked at 2.1% in 1962, the highest ever recorded.
- 1987, 1999, 2011 — five, six, seven billion — The 5 billion mark was crossed on 11 July 1987, now observed as World Population Day. The six billionth member was born in Sarajevo on 12 October 1999, and the United Nations placed the seventh billion at 31 October 2011.
- 2022 onwards — eight billion and two question marks — World population reached 8 billion on 15 November 2022. Since its peak the growth rate has fallen steadily, with 0.1% a year projected for 2100, while one estimate still puts the total at 10 billion around 2050. Whether the curve keeps rising or flattens is why the graph ends in two big question marks.
Hint
The rise was never steady. Each cultural revolution — tool-making, agriculture, science and industry — was followed by a jump, then a long flat stretch, then the next revolution pushed it up again.