[Baeocystin]

>It's an interesting point, though: is it better long term for environmentally-conscious people to have fewer or more children?

Earth has produced a grand total of one species that even has the potential to be effective stewards. That's us. Earth is already on the far backside of how much longer it will be habitable due to the Sun. And I see no reason to think that any other intelligence that did evolve here wouldn't be beset by the same problems we have now.

So (IMO) intelligent, conscientious people having fewer children helps nothing. We (humans) are the best thing our biosphere has got, by a long shot, in terms of long-term preservation of life, which is something that I personally think is of great importance.