The 20th century saw explosive population growth, fueled by a combination of declining infant mortality, decreasing violence and steady growth in agricultural productivity. These trends resulted in large part from technological advances — like chemical fertilizers, genetically modified food, antibiotics, and vaccines — which acted as a tremendous boon to human welfare. By the 1970s, some were convinced that population growth would soon lead us back to a dark age of famine, disease and war.
Instead of the downward spiral forecasted by Thomas Malthus, a somewhat unexpected trend emerged. Citizens of industrialized countries in the late 20th century began having fewer children. So few, in fact, that current fertility rates in Europe, Australia, East Asia and other developed regions are well below replacement levels. The result has been an aging population that faces workforce shortages and empty nests. Despite these facts, some journalists and pundits have renewed the call to have fewer kids. Why? Their main worry is climate change.
A number of popular articles (and books) have implored people to have fewer children as a way of minimizing anthropogenic global warming. One reason they give is that the average child in developed countries will have a large carbon footprint. And they’re right: People born in the United States or United Kingdom, for example, will consume quite a few resources. This consumption will also produce pollution — not just carbon dioxide that contributes to climate change, but also air and water pollution from the energy that powers our cars and houses, and the trash we create that ends up in landfills.
Pessimists argue that new children are an easily avoidable burden to the planet. But this chain of reasoning is incomplete, mainly because it only emphasizes the cost side of the calculus that we should use to assess whether kids are a net benefit or a net cost.
Economists have long argued that more people means more minds productively working on the kinds of problems that plague us. Although we often pollute as a consequence of using carbon-based energy sources, these energy sources also fuel a wide array of industry, including the invention of new kinds of energy that cost less and reduce pollution. Of course, a carbon tax would likely nudge this along a bit more quickly. But that’s just another way of saying that human ingenuity can often be tapped to solve challenges created by living together on a common planet.
Keep in mind too that pollution is not just a cost. Pollution almost invariably accompanies processes that produce valuable goods like food, medicine, shelter and transportation. More developed countries pollute more, but they also produce far more (and far better) goods than less developed countries. And these goods make everyone’s lives better, especially people who live in countries with low carbon footprints, who would otherwise lack cell phones, vaccines, chemicals that preserve food and a cornucopia of new forms of technology, scientific insights and art forms. Reduce the already shrinking number of polluters in developed countries, and you multiply misery in poorer countries.
Opponents may argue that below some threshold population growth can improve social welfare by increasing the number of people we trade with. But, they may think, we are past the optimum or sustainable point of population growth, and coming dangerously close to a point of no return.
People have been arguing this for centuries, though, and the debate reached a climax in the 1970s when Paul Ehrlich predicted widespread starvation in poor countries, along with dramatic increases in pollution and the price of commodities in rich countries. Ehrlich’s fiercest critic, Julian Simon, countered with an argument similar to the one developed above. In fact, Simon decided to put his money where his mouth was by betting Ehrlich that the price of a handful of common commodities would fall rather than rise, as new resources were discovered and invented in response to short-term scarcities created by a growing population.
Simon won the bet, and history has not been kind to Ehrlich.
What the debate illustrates is that the relationship between population growth, resource use and pollution is complex. Contrary to our initial intuitions, we do not live in a zero-sum world where the existence of more people must result in more pollution and fewer resources. Under favorable political institutions, there simply is no particular point at which population growth is bad (there is no such thing as a specific number above which more people are a threat to the planet, or to each other). This is because although resources are finite, they are not fixed. Human minds transform old resources into new products, including products that clean up pollution, increase food production, and yield new medicines.
Whether you end up accepting or rejecting our argument, any attempt to show that we should have fewer kids should include the social benefits of children as well as any social costs they create. Reasonably intelligent people born in developed countries have access to education and opportunities that can transform them into idea machines.
When more is less
Having said that, it must be acknowledged that the benefits of children are uneven. Children born to parents who have the kinds of traits that predict success in the modern world — including intelligence, compassion and impulse control — are likely to thrive. But children born into poverty are very likely to suffer. This is true in part because children resemble their parents, not just in appearance, but also in the suite of traits that helped to make their parents either successful or unsuccessful.
Children who are born in countries with repressive political institutions are — for myriad reasons — less likely to bring the sorts of benefits that those born in the developed world can offer. And because of the increasingly negative correlation between income and fertility, most population growth is occurring among impoverished people in countries with poorly functioning political institutions.
Those who urge educated and compassionate citizens in developed countries to have fewer children are missing their target. If their call were heeded, people around the world would be considerably worse off. Imploring people in Spain or Norway to restrict their reproduction does nothing to solve the problem of precipitous population growth in Africa and the Middle East. And it does a lot to impede the development of new ideas, and the creation of value.
By the end of the current century, the population of sub-Saharan Africa alone is expected to triple. The problems this creates may eventually be mitigated by important efforts to supply contraception to poor women. But telling people in developed countries who are well-placed to have children to refrain from doing so is misguided. If anything, they should reproduce more, not less.
Carter Dillard, a prominent supporter of the view that we should have fewer children (to minimize our carbon footprint), says, “For too long, parenting models focused on the choices of the parents without putting them in the context of a larger community.” Broadly speaking, we agree. But we think that when the math is done, it will imply that social welfare will increase rather than decrease with educated people in developed countries having more kids.
In fact, we’re willing to bet that if you’re reading this essay, you should probably have (more) children.