Another great Tyler Cowen article:
To put those worries out of mind, ask yourself a simple question: Is the remedy for climate change, to the extent we find one, more likely to come from North America or New Zealand? Obviously, the wealthier and more populous America is a more likely source of technological innovation, even though it is also a more significant source of greenhouse gases. So if you think progress in this fight is possible at all, you ought to be betting on the more populous nations. By having more children, you are making your nation more populous — thus boosting its capacity to solve the problem.
But even if your kid doesn’t grow up to be a leading scientist or environmental crusader, she may still have a real impact. More people, according to Nobel Prize-winning economist Paul Romer, create bigger markets for innovations. There are more medicines for common diseases than for rare diseases, precisely because market size is larger. By having more kids, you are increasing the demand for remedies to climate change. For instance, there are significant fixed costs to coming up with higher-quality electric cars or better solar panels. Investors put money into these areas only because they hope to sell a lot of units. Your children will help boost demand.
So people without kids are doing the environment the most harm?