I've edited this essay to respond and incorporate points made by commenters. Thanks to all who have provided feedback.
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This is something I see come up in EA social media spaces and I am keen to state an argument against anti-natalism in clear, strong, and persuasive terms. Typically the anti-natalist case is presented as a way to avoid a significant impact on the climate. I think this is flawed: while the average human certainly has net-negative impact on the climate, the average human also has a net-positive impact on total human well-being, simply by existing and leading a net-positive life.
First, let's survey some morally relevant areas that you have control over, and that having children could impact.
You matter
My well-being and yours, and your potential children, all have moral worth. We matter too. If your altruism completely excludes your own well-being, I would be concerned about how sustainable it is. See further notes at the bottom.
Your children matter
Assuming your potential children live average lives, they'll probably experience a lot more happiness than suffering and their lives will be well worth living. The impact that each individual has on the climate is dwarfed by the well-being that person experiences in their own life. These are contestable claims: there are lively arguments over the "total view" vs. the "average view", but I take a total view on this. If you take the average view, you might disagree you should take your potential childrens' well-being into account.
Your own impact on EA matters
Having children will influence your own impact within your career and life on the world. For instance, someone in a particularly impactful career might avoid having children if they think it would lead them to sacrifice making a difference in their career.
In conclusion
If you want to maximize total aggregate happiness in your decision,
- your primary concern should be yourself and your potential co-parent's happiness because that will be massively influenced by your decision - potentially either way, depending on your preferences. Managing own happiness and well-being is an important part of maximizing total aggregate well-being. Therefore, if you don't want to have kids, don't have kids - you don't need climate change to justify that decision!
- Then, as a distant second you should consider the net positive impact your children would experience through living their own lives.
- As an even more distant third priority, think about the impact that having kids would have on your own ability to have an effective career. Now, this may be a persuasive argument against having children for some people. For others, including those earning to give, or people who would simply be less happy not having children, having children might function as a positive motivator that enables you to have a more effective career than you would otherwise.
- In terms of maximizing total well-being, your kids' impact in the climate is a distant fourth relative to all those other concerns I've raised. The magnitude of their impact on the climate is likely to be much, much smaller than any of the three other factors I have raised.
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Postscript
"Is it really true that "effective altruists" should consider their own well-being, too?"
It is true that "altruism" excludes your own well-being by definition. However, a moral system that arbitrarily excludes the agent's own well-being seems arbitrarily selective. Certainly any consequentialist or utilitarian would want to weight their own well-being equally with others.
But this is not just a consequentialist approach. Wider philosophical and religious discourse around morality are also premised on concern for self. The religious command is "Love thy neighbour as thyself", not "Love only thy neighbour, not thyself". Kant's deontological rule is "act only according to that maxim you would have as a universal rule", not "act only according to maxims that would benefit others".
How do we know the negative impact of a marginal individual on climate change is smaller than the positive impact an individual has on their own well-being?
My initial thinking: most of the negative utility of climate change is related to its negative impact on human life. It makes human life somewhat less enjoyable. At its worst, the negative utility of climate change could end all human existence. So there is a scenario in which the negative utility of climate change is equal to the positive summed utility of human existence. However, this scenario is highly unlikely: <1%, and possibly <0.1% (Ord, 2020). So we should strongly downweight the negative utility of climate change.
That said, I think what I've missed here is that the negative utility of human extinction doesn't just cancel out the positive utility of everyone existing now; it is worth the positive utility of everyone who might exist in the future billions of years. So this is part of my argument I might need to reconsider. I'll try to consider this further.
Interesting, appreciate your reply! I think you raised a couple of concerns:
Have I understood your argument right?
I think (1) is complicated. Even if it's true that bringing an additional child into the world results in less for everyone else, the primary beneficiary isn't the parents of the child, but the child themselves (although this depends on whether you take a "total view" or "person-affecting" view of population ethics. It's true under the total view, which is my own perspective. If you take the person-affecting view, you could disagree). The key point I was trying to make in my post is the benefits accruing to that one child are greater than the total sum of harm that additional child does by existing and producing a carbon footprint. I think other commenters were right to say I haven't made a strong affirmative case, but at least, I'd appeal to you to consider whether the calculations need to be done.
I'll attempt a brief calculation, though. I don't necessarily stand by these figures, but my point is that (from a consequentialist point-of-view) doing a calculation like this is important for understanding whether anti-natalism is a good response to climate change.
The largest impact of climate change on human beings in expectation seems to be forcing people out of their homes and communities to migrate, possibly across thousands of miles to different countries. Many will die of famine, thirst, or other acute problems, but all have their lives uprooted. Understanding the number of people this will impact is difficult, but the best estimate I can find is roughly 200 million. If this scales linearly with the number of people in the world, roughly 8 billion now, then for every 40 new people in the world, we'll have 1 new climate refugee. Is it worth coming into the world if you have a one in forty chance of being a climate change refugee, or causing someone else to be? Of course no one can actively make that choice, but we can make that choice for someone "in expectation" if we're in a position to decide whether to bring them into the world. To me a 1 in 40 chance of a bad outcome is worth a 39 out of 40 chance of a good outcome.
But even though that still seems a worthwhile gamble, in reality, I think the situation is much, much less dire than that. The impact of climate change won't scale linearly, because as we get more people, we'll spend more resources on carbon capture and transitioning to a zero emission economy. This does impose costs on people, but the sacrifice of driving a bit less, or spending a bit more money on solar panels, or other forms of getting to carbon zero, seem less of a sacrifice than not existing at all. This isn't completely obvious, because the burden is across the whole of society, but I'll have to leave that exercise for the future.
For the second point (2): people have done their best to work out the economic impact of climate change. The best indications are in the range of 2-10% of world GDP. On average, the US and other developed economies grow about 1-2% a year, or 10-20% a decade. So the impacts of climate change, and responding to it, will cost us a decade of growth and rise in living standards,. But, overall, it seems like living standards will still be higher in future than they are now, even accounting for the impact of climate change.