Several years back, the economist Bryan Caplan wrote a wonderful book called Selfish Reasons to Have More Kids. Caplan argued that most parents underestimated the benefits of larger families and were engaging in costly parenting strategies that yielded few real benefits. Thus, he said, if you love kids, you should have lots of them.

From NPR this week comes a story that might well be called “anti-Caplan” in every dimension. It is a profile of bioethicist Travis Rieder and others like him who argue that it is immoral to have many children, if any at all, because of the burden that additional children place on the Earth’s ecosystem. Given that we are already, Rieder claims, on the road to climate disaster, adding more children will both make matters worse and condemn those children to a horrible life on a worsening planet. His argument might well be called “Altruistic Reasons to Have Fewer Kids.”

More specifically, he argues that children are what economists call negative externalities: “We as parents, we as family members, we get the good. And the world, the community, pays the cost.” As it turns out, that claim is almost entirely wrong. It is parents who pay most of the costs of having children and the rest of us who reap the benefits.

I am not going to contest some of the claims about climate change Rieder and others in the article invoke. He does tend to take the most extreme predictions of climate models as gospel truth when the recent data have suggested that reality is closer to the much more modest predictions. However, even if the worst case scenarios are true, Rieder misses a number of important points about population growth that need to be considered.

Human Beings are Producers

Most of the Western world is dealing with fertility rates that are below replacement.He, like so many environmentalists, sees human beings only as consumers of resources. So one core statistic he trots out is that the amount of CO2 saved by not having a child is roughly 20 times what we can save through traditional things like driving hybrids and recycling. Therefore, he and the other people discussed in the story conclude, if we really want to “save the planet,” we should have fewer, if any, children.

But this is single-entry economic and moral bookkeeping. This view ignores the idea that humans are also producers. As Julian Simon reminded us so often, more people not only means more hands to work and more minds to create, it means more different people with different ideas. Increases in population not only deepen the division of labor and productivity by their sheer numbers, they also take advantage of the fact that each of us is unique which leads to new ideas and innovation.

Human progress depends upon the increasing productivity that comes from a finer division of labor and new ways of doing things. And those are the result of more people.

It’s not, as a student in the article suggests, that one of those kids that isn’t born might have come up with a “solution for climate change,” but that each and every one of those kids that isn’t born would have contributed to greater economic growth, which is nothing more than the more effective and efficient use of the resources we have.

Such growth is what has made it possible for the Earth to sustain 7 billion lives of increasing length, comfort, and quality. Reducing the population might mean we use up more resources by losing the efficiencies that come from a larger population’s greater ability to innovate and productively specialize.

The benefits of having more kids are not primarily to the parents involved, though as Caplan points out there are many. More people means we are better able to beat back omnipresent scarcity and carve out a more inhabitable planet for more people who live longer, better lives.

This is the most fundamental error of so many environmentalists, especially those arguing for reductions in the population: they see humans only as consumers of resources and not the source of the very innovations that enable us to use resources more effectively and the riches that enable us to have a cleaner, healthier planet.

Demographic Transition

The best way to save the planet is not to have fewer kids, but to have as many as you can afford.The other crucial point Rieder and people like him miss is that the Earth’s population is already in the process of stabilizing. One of the most agreed upon empirical facts of history is the so-called “demographic transition.” As societies become wealthier and more industrialized, the incentives facing parents change and family size falls. Once mom and dad, or perhaps only one of them, can earn enough income to support a family, and there’s no farm or cottage industry that requires the whole family pitching in, the need for many children is much less and parents seek to control their fertility.

The Western world began to go through this transition over a century ago, and the rest of the world has followed in turn. Most of the Western world is dealing with fertility rates that are below replacement, and rates of population growth in all but a handful of countries worldwide have fallen in the last few decades.

Thankfully Rieder does not want to use Chinese-style coercion to limit family size, but he’s not afraid to tax larger families more heavily. Even that isn’t necessary given the reality of the demographic transition: in a free society, human beings naturally limit their fertility as they get wealthier. Again, the best way to save the planet is not to have fewer kids, but to have as many as you can afford and let their productivity enable us to use resources with more efficiency and create more progress.

Anti-Life, Anti-Human

The radical wing of environmentalism is, as Ayn Rand said decades ago, “anti-life” and “anti-human” in its belief that humans are the scourge of the planet and not the source of its progress. After all, if the important thing is saving the planet by reducing our carbon footprint, why stop by persuading people to not have kids?

Why not persuade currently living people, especially young ones, to reduce their lifetime carbon footprint by killing themselves? The logic is no different.

That they don’t make that argument suggests that “saving the planet” really isn’t the overriding issue here. Like so much else in the Green movement, this seems to be about protecting their own comfortable lives against what they think will happen when everyone else is able to live lives like they have. They got their progress and health and children, but everyone else needs to sacrifice for the sake of the planet. That Rieder does have a child is some evidence of this point.

Not only is Rieder’s argument deeply immoral and reactionary in how wrong it is, it turns out to be far less altruistic than it first seems. Nothing could capture the total failure of radical environmentalist anti-natalism better than calling it “selfish reasons everyone else should have fewer kids.” Let’s hope, for the sake of both actual humans and the planet we live on that these environmentalist arguments are as infertile as their proponents wish humans were.