How Many People Can the Earth Support?

December 18, 2023 Jeremiah Hendren

How Many People Can the Earth Support?

Cohen, Joel E.
The Sciences 35, no. 6 (1995): 18-23
https://doi.org/10.1002/j.2326-1951.1995.tb03209.x

Two thousand years ago, the Earth probably had 100-300 million people. The human population reached one billion in 1800-1830, and seven and a half billion in 2017. Adding the latest billion took 12-13 years. Another billion people are expected in the next 12 years. Though the number of people more than doubled from about 3.7 billion in 1970 to 7.5 billion in 2017, experts dispute whether the number of people will ever double again to 15 billion. Nevertheless, the population of Africa, the continent with by far the lowest income per person and by far the fastest rate of population growth, will nearly quadruple between 2015 and 2100, according to the United Nations’ 2015 projections. At current birth rates, a woman has 2.5 children during her lifetime on average worldwide, still above the 2.1 children per woman that would stabilize population size in the long term. The population would double in 59 years if it continued to grow at its present rate of increase of nearly 1.2 percent per year, but a constant growth rate seems very unlikely. It is much more likely that the average number of children per woman and the population growth rate will continue to fall as they have over the past half century.

Joel E. Cohen

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