> Assuming we even make it another 100 years, there is no way to know what our population will look like then, or whether we could not pull another technological/logistical revolution out of our asses, or whether global cultures would start to embrace a further explosion of population.

It seems like women in pretty much all cultures where women achieve financial independence and have control over how many children they have, choose to have 0, 1, 2, or rarely 3. Which makes sense given the risks and costliness of childbirth for them.

So I would guess that any culture that results in population explosion would have to either have medical advances that address the risks and costs of childbirth, or go backwards on women’s independence. Or really sweeten the deal in terms of financial and other incentives, but I don’t imagine that would fare very well.