1798

Population Growth

Thomas Robert Malthus (1766–1834)

The invention of agriculture after the end of the last glacial period some 12,000 years ago spurred the development and expansion of cities and a slow growth of the population (from a post-glacial estimate of about 1 to 10 million people worldwide at that time). The scientific and technological advances of the Enlightenment helped the world’s population exceed 1 billion people by around 1800. Since then, the rapid expansion of agriculture and transportation infrastructure associated with the Industrial Revolution, as well as the rapidly accelerating pace of technological (especially medical) advances, have further spurred dramatic population growth. The world’s population was about 1.8 billion by 1900, but it then grew rapidly to more than 6 billion by 2000 and is expected to surpass 7.5 billion people by 2020.

The “Malthusian trap,” named after English political-science scholar Thomas Robert Malthus, suggests that advancements in the standard of living due to scientific or technological innovation that lead to increased food production will essentially be cancelled out by concurrently large increases in population. Malthus focused much of his research on the economics and demographics of population growth. The “trap” that he noted in his famous 1798 essay on population growth, An Essay on the Principle of Population, was that population grows dramatically faster than food supply, causing the poor to suffer disproportionately from famine and disease, and increasing the pressure on societies to further increase food production, reinforcing the cycle. Malthus was a pessimist about the future of human society and human happiness in the face of continued scientific and technological advancement—in stark contrast to many of the Utopian writers and philosophers of his day, who saw those advancements as ultimately improving the human condition.

Malthus’s views were controversial in his day, and they remain controversial today. The following are just a few of the hot topics that are under severe scrutiny around the world today: Must human societies inevitably grow during times of abundance, as Malthus hypothesized? Is it the responsibility of individuals to help keep population growth in check? Should governments incentivize (or force) limits on family size? These and other related questions will continue to be debated as the world’s population potentially swells to 10 billion people in the next few decades.

Main image: A crowded subway station in Brazil, 2017. Inset: 1834 engraved portrait of Thomas Robert Malthus.