Worries About Overpopulation Are as Old as Civilization
The Epic of Atrahasis was written by an unknown Babylonian author around 1700 BCE. It’s one of the oldest stories in the world. In it, the gods tire of doing tedious labor on earth, so they create human beings to do work for them. This works for a while, but eventually the humans begin to multiply. The teeming human population becomes so loud that it irritates the gods. The immortals decide that the only way to deal with their noisy neighbors is to kill them (hey, we’ve all been there). The gods try to murder the humans with droughts and plagues, but the people keep multiplying.
In the end, the gods send down a cataclysmic flood; it kills all of the humans except those on an ark constructed by a man named Atrahasis ( meaning “very wise”), who had been warned of the flood by one of the gods. The gods decide to let Atrahasis and his passengers live, but they make sure to prevent the human population from getting out of control in the future. From that point forward, the gods decree that some women will be unable to bear children, demons will kill children before they can grow up, and some women will have to be celibate priestesses. Satisfied that they have dealt with the population problem, the gods stop trying to annihilate humanity.
It’s telling that one of the world’s oldest stories — dating to a time when there were somewhere between 25 and 50 million people (in the range of the modern population of California or Poland) in the entire world — reveals a deep fear of overpopulation. And it wasn’t just the Babylonians. This story was, of course, echoed in other works like the Epic of Gilgamesh and the story of Noah in the Bible. It seems that people have always been worried that there are too many of us.
As the human population grew — much more slowly than it does today — in ancient times, people experienced periodic worries about human population. Plato, in the 4th century BCE, recommended that government strictly limit birthrates. Five hundred years later, when the world population was 2–4% of what it is today, Roman author Tertullian wrote:
What most frequently meets our view (and occasions complaint) is our teeming population. Our numbers are burdensome to the world, which can hardly support us . . . . In very deed, pestilence, and famine, and wars, and earthquakes have to be regarded as a remedy for nations, as the means of pruning the luxuriance of the human race.”
It seems that humans have always worried about our growing numbers. We’re aware that the earth has limited resources, and that our use of them is unsustainable. In ancient times, what Tertullian describes did happen from time to time. Plagues and natural disasters kept the human population from growing too rapidly. But during the Industrial Revolution, we broke free of the old constraints.
To one billion… and beyond
For most of history, the human population grew almost imperceptibly; from 10,000 BCE to 1700, the average annual growth rate was .04%. But the Industrial Revolution (and the second Agricultural Revolution that preceded it) changed everything. It took all of human history up to the year 1803 to grow the global population to a billion. The second billion took 125 years. By the late 20th century, we were adding a billion people every 10–15 years.
The unprecedented growth of the world’s population brought another wave of population anxiety. The most famous proponent of this view was Thomas Malthus, who lived just as the global population was hitting a billion. He noted that population seemed to be increasing exponentially while food supplies were only growing arithmetically.
Malthus argued, relatively correctly, that population growth had always been limited by tragedy — famine, disease, and the like. The “Malthusian Trap” ensured that any excess resources would create population growth; when food supplies were outstripped by population, the number of humans would decline again. He foresaw his society’s population boom ending in disaster, especially for the poor.
Malthus often serves as an historical punching bag — after all, his big prediction that the population growth of the early 1800s would soon lead to mass starvation was very wrong — but he was actually right about quite a lot. He noticed that his age’s population growth was unprecedented, and he was insightful about the factors that had limited population in the past. His mistake was that he didn’t see the changes happening around him that would make the old constraints on population irrelevant.
The population growth of Malthus’ age was accompanied by a remarkable wave of innovation. Scientific farming and new fertilizers caused the food supply to increase much more rapidly than ever before. Medical discoveries limited the spread of disease, drastically extended the human lifespan, and made progress against child mortality. Most societies eventually went through a demographic transition in which better conditions led to a lower birthrate and population stabilized after a period of growth.
Malthus was wrong — the rapid population growth of the 1800s was not reversed by tragic famines or plagues. But this didn’t stop later thinkers from echoing his fears. Malthus might have been incorrect about his era, but that didn’t necessarily mean that a high population was sustainable in the long run. Perhaps the innovation of the Industrial Revolution had been an anomaly. Perhaps human ingenuity couldn’t keep the Malthusian Trap away forever.
Overpopulation and the environment
In the 1960s, some activists again became convinced that humans were on track to exceed the earth’s capacity. They weren’t just concerned with the effects of human population growth on people; the relatively new field of ecology showed that when one species exceeded its habitat’s carrying capacity, it could wreak havoc the entire ecosystem.
The Club of Rome was founded in 1968; in 1972, they would publish The Limits to Growth, which predicted that population and economic growth would run into hard limits posed by the planet’s finite resources. In 1968, biologist Paul Ehrlich published the bestseller The Population Bomb, which began with these ominous lines:
The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate.
Though the scenarios he envisions in the book have not come true, Ehrlich never backed off of his main argument. He maintains that a growing population will eventually run into the hard limits posed by the earth’s finite carrying capacity (the book was revised to include new predicted dates for mass starvation). Thinkers like Ehrlich have argued that human ingenuity and the exploitation of the earth’s marginal resources will only get us so far — eventually, we will use up the arable land or the atmosphere’s ability to absorb our pollutants, and disaster will ensue.
Now, as we face down climate change, overpopulation has once again become a worry. Some insist that limiting population growth is a key tool in saving the world from warming, while others argue that talk of population control is paternalistic and reminiscent of twentieth century eugenics. Whichever side of the debate you agree with, the truth is that it’s irrelevant. It’s hard to see government actions making a big difference in population growth — with the exception of China’s “One Child Policy,” no government has ever successfully limited its population’s growth. Many countries with declining populations are worried about the economic impact of their situation, and are trying to boost their population. Even China has loosened its efforts to control procreation.
Perhaps we will be able to support our eventual population of more than 10 billion people in perpetuity. Perhaps we will look back on the past 200 years as a time when humanity recklessly exceeded the earth’s carrying capacity until we had destroyed so many of the earth’s systems that we were forced to bring our numbers back down. Whichever way our experiment with having 7 billion people on the planet goes, some portion of humanity will worry about it. After all, we’ve been doing so for almost 4,000 years.