Environmentalism Needs Pronatalism

Environmentalism Needs Pronatalism

Since New York Representative Alexandria Ocasio-Cortez pondered the question out loud last month, the idea that climate change makes it immoral to have children has gotten a great deal of play in major media outlets. The most serious pushback, first offered by Tyler Cowen in Bloomberg and echoed by Senator Mike Lee on Tuesday, centers on Nobel-prize-winning economist Paul Romer’s idea that more people means more innovation, and more innovation is necessary to fight climate change.

Despite the ridicule coming at Senator Lee from the usual places, Romer’s idea is well-supported as far as theories of innovation go. Even so, it’s understandable why proponents of decisive climate action might not be willing to bank on a promise of some unspecified future innovation. Is it smart to put so much trust in something that we don’t even know exists yet?

In fact, there’s an even more concrete and compelling reason why a campaign to reduce birthrates is likely to hurt the environment: If environmentalists stop having children, the world will have fewer environmentalists.

How Social Pressure Works

Most people exercise social pressure in a more or less indiscriminate way. If it would be good for the world that people do [x], then I’ll try to convince people to do [x].

Not all people, of course, are equally receptive to social pressure. Most of the time this doesn’t matter. When we try to exercise pressure on people to consume less, to buy more efficient cars, or to use one square of toilet paper when visiting the loo, every bit helps, and if some people don’t listen— if some people scoff, or continue to use multiple squares— at least we’re no worse off than before.

The situation is different, however, when the pressure pertains to having children. Suppose we could quantify the quality of being receptive to social pressure. In fact, this quality is part of what personality researchers have identified as conscientiousness, one of the five core dimensions along which personalities can vary.

So who’s most likely to respond to social pressure to consume less?— the most conscientious. Who’s most likely to use one square of toilet paper?—the most conscientious. And who’s most likely to have fewer children if politicians and journalists set it up as the moral thing to do?— naturally, the most conscientious. People who read thinkpieces about environmentalism—including you, dear reader— are probably some of the most conscientious in our society today.

Now here’s the problem: conscientiousness has been estimated to be about 44% heritable. In other words, 44% of the variation in how receptive a group of children is to social pressure can be explained by the receptivity of their parents, with most of the rest apparently due to random variation. In short, if you’re more conscientious, your children are likely to be more conscientious as well.

So here’s how the story plays out:

  1. Politicians and journalists tell people to consume less and have fewer children.
  2. The most conscientious people take this message to heart, consume less, and have fewer children.
  3. The next generation is slightly less conscientious on average, and less inclined to watch their carbon footprint. The generation after that is even less so.
  4. After a few generations, if anyone is still preaching the gospel of low consumption, there’s no one left who cares to listen!

This is a problem that economists call adverse selection. It’s a problem that runs through finance, insurance, drug policy, and a whole host of other arenas. No matter the problem you’re trying to solve, adverse selection can mean that the obvious solution might be the worst thing you could do in the long run.

(I’m going to assume here that conservative fears about this social pressure leading to forced sterilization are indeed unfounded, and that the campaign will remain one of social pressure. Coercive policy could indeed solve the adverse selection problem, but at a moral cost so great that I would not venture to tar most environmentalists with it.)

Practical Implications

Let’s assume the worst estimates of the carbon footprint of having a child, and assume that we can’t count on any technological breakthroughs as in the Romer story. Even in this worst-case scenario, the adverse selection problem means that anti-natalism is still a cataclysmically bad environmental strategy. It’s not likely to make a significant impact on the number of people in the world in the long run, but it is likely to ensure that those people are less conscientious, and—therefore—less likely to care about the environment.

Instead, it’s necessary to be smart about who’s listening when we exercise social pressure on the question of childbearing. Here are a few practical implications.

  1. If the adverse selection story is true, it means that running pieces on the environmental cost of having children is one of the most harmful possible environmental strategies. Push back. Don’t let the anti-natalist case go unanswered. Write letters to the editor; call your representatives; challenge your conscientious and environmentally engaged friends on Facebook and in real life.
  2. Have more children. I feel confident saying this indiscriminately, knowing that those who read this and take it seriously are likely to be more conscientious than average. In the long run, the only way to ensure that the future earth is filled with the kind of people we’d like it to be filled with is to make them ourselves.
  3. Exercise positive social pressure. Encourage your pregnant friends. Tell them they’re doing the right thing. You can feel confident doing this indiscriminately too, for the same reason that I do it confidently here.


At the end of the day, none of us—either by our own fertility decisions or by exercising social pressure—can meaningfully affect the number of people in the world in the long run. What we can affect by our own fertility decisions and by exercising social pressure, is what kind of people exist in the world in the long run. For the sake of the earth’s climate, ecosystems, and future generations, I can only hope that shortsighted journalists and politicians do not succeed in convincing those who care deeply about the environment to deprive the world of future environmentalists.




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  • 1


    Apr 05, 2019 at 11:35 | Reply

    The selection problem is indeed an interesting aspect of this debate. I would be curious to see what a utilitarian cost benefit analysis with perfect information would calculate: does the 44% heritability of conscientiousness truly outweigh the negative emissions of an additional person growing up in the developed world?

    And if so, should we encourage the “enlightened” to have as many babies they can raise, and try to discourage the less conscientious? I see the problem of adverse selection and it may be a mitigating factor against extreme anti-natalistic claims, but I don’t believe it’s sufficient to push for a clear pro-Natalist position.

    Moreover, in terms of policies that don’t rely on individual conscientiousness, there are other ways to curb procreation numbers other than extreme measures such as sterilization. For one, governments could refrain from subsidizing having children, or (admittedly more controversial) tax for having more than 2.

    • 1.1

      Cameron Harwick

      Apr 05, 2019 at 23:15

      Good question about the quantitative estimates; that’s actually one near-future project that I’d like to start working on soon.

      I’d be wary of relying too heavily on discouragement since that would probably just push the adverse selection problem to the global scale. If Europe (e.g.) ends up with a highly conscientious but extremely small population, what’s that worth if the rest of the world carries on as normal? In the absence of a global government, maximizing the conscientious seems like a better object of national policy than minimizing the non-conscientious.

    • 1.2


      Apr 12, 2019 at 13:18

      Right so the reason I would recommend policies or incentives for limiting procreation is to get rid of the adverse selection problem, as conscientious and non-conscientious people would be equally affected by the incentives. From what I understand, you are saying we would then have a higher-level adverse selection problem, because we would have more conscientious countries with smaller populations, and non-conscientious countries with higher populations. For this to be true, it would have to be the case that (i) there are variations across countries in terms of how many conscientious people are there, and (ii) European and North American countries indeed have more conscientious people.

      If we can believe the BBC article (link below), (i) is correct, but also shows that African countries actually have more conscientious populations than other regions, meaning we Europeans actually should limit European population growth and encourage (for example) more African population growth.
      An additional reason maximizing Europeans and North Americans in particular is not a good strategy is that they are the most polluting. The average Canadian pollutes 8 times as much as the average Indian, and the richest billion is responsible for half of the CO2 emissions.

      As the poorer countries become richer, they will also have higher pollution per capita, so I also believe overpopulation in those regions is problematic from an environmental point of view. However, even here there are foreign policies that can curtail overpopulation. The most liberal way of doing this, is to focus on avoiding unwanted pregnancies in particular, by investing more in girls’ education. Another way of doing this is by donating to better health care in low income countries, as there is a negative correlation between the birthrate and the availability of health care (basically if fewer children die, parents have fewer children) (see Factfulness by Hans Rosling, 2018).

      Finally, I understand it’s tempting to reject anti-natalism by proposing pro-natalism, as for most people, having children is such a meaningful aspect of life that we would rather not consider to be immoral. However, I don’t think we should therefore push for a child-maximizing strategy. I think it would be healthier to acknowledge the counter-arguments to having children, and if we still choose to have children trying to mitigate the negative as much as possible by raising them to be responsible and caring. We already have a strong cultural bias favoring procreation, leading to most people not even questioning it. Choosing to have children is the most consequential decision any person can ever take, and yet I never hear people ask each other why they want children (whereas those who wish to remain childless constantly get interrogated). I understand not wanting to blame those who choose to have kids, but we can at least refrain from praising them.

      Very curious to see what comes out of your quantitative estimate project though!


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