-
Do we? It's not like everyone is doing it
Maybe I'm a bit pessimistic, but I think the only way we can avoid real climate catastrophe is some combination of (i) reduce the carbon intensity of "Western" lifestyles and (ii) reduce the growth rate in the number of people living those lifestyles.
Given that during our lifetimes we will see massive climate-driven displacement of people, largely into Western countries, the planet just doesn't have that much spare capacity for loads of Western kids.
I hope I'm wrong.
Somehow we have to discourage people in wealthy countries from deciding to have that third child. Economic disincentives don't work and are regressive, so how else do you propose to achieve it without cultural norms?