For nearly all of human history, there haven’t been that many of us. Around the year zero, Earth’s population is estimated to have been 190 million. A thousand years later, it was probably around 250 million. Then the Industrial Revolution happened, and human population went into overdrive. It took hundreds of thousands of years for humans to hit the 1 billion mark, in 1800. We added the next billion by 1928. In 1960, we hit 3 billion. In 1975, 4 billion. That sounds like the route to an ...

For nearly all of human history, there haven’t been that many of us. Around the year zero, Earth’s population is estimated to have been 190 million. A thousand years later, it was probably around 250 million. Then the Industrial Revolution happened, and human population went into overdrive. It took hundreds of thousands of years for humans to hit the 1 billion mark, in 1800. We added the next billion by 1928. In 1960, we hit 3 billion. In 1975, 4 billion.

That sounds like the route to an overpopulation apocalypse, right? To many midcentury demographers, futurists, and science fiction writers, it certainly predicted one. Extending the timeline, they saw a nightmarish future ahead for humanity: human civilizations constantly on the brink of starvation, desperately crowded under horrendous conditions, draconian population control laws imposed worldwide. Stanford biologist Paul Ehrlich wrote in his best-selling book, “In the 1970’s, hundreds of millions of people will starve to death” because of overpopulation.

None of that ever came to pass. The world we live in now, despite approaching a population of nearly 8 billion, looks almost nothing like the one doomsayers were anticipating. Starting in the 19th century in Britain and reaching most of the world by the end of the 20th century, birthrates plummeted — mostly because of women’s education and access to contraception, not draconian population laws. In wealthy societies where women have opportunities outside the home, the average family size is small; in fact, it’s below replacement level. Called the demographic transition, it is one of the most important phenomena for understanding trends in global development.

There’s still significant debate among population researchers about the extent of the sea change in population trends. Researchers disagree on whether global populations are currently on track to start declining by midcentury. There’s also disagreement on what the ideal global population figure would be, or whether it’s morally acceptable to aim for such a figure. While academic research seeks to nail down these questions, it’s important to be clear what is consensus among researchers.

Our projections around population are used to make global health and development policy. They’re critical for planning, especially about climate change. Fears of overpopulation sometimes turn into hostility to immigrants, those who choose to have large families, and countries in an earlier stage of their population transition. Having an informed conversation about population is crucial if we are to get humanity’s future right.

(Source: https://www.vox.com/)

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