Lets call environmentalism a superior economic good
As we get richer, we want more environmentalism.
[Note:] Once we are the level of income where it becomes superior. Very low levels of income it is a generally inferior good, people want less of it as they get richer.
We live in a place, developed world, where it is a superior good. Environmentalism could be called oranges. Things we don't consider environmentalism could be apples (Fossil fuels, industrial development, etc).
Everyone generally likes oranges, but apples are super cheap. The market clearing price for apples is far lower than oranges. We think there is a dead weight loss (the external costs out weigh the benefits) because we KNOW oranges are far better. However it would be more costly to replace oranges with apples (the consumer costs out weigh the benefits). How would we make oranges cheaper? One solution that is purposed in many parts of the county is to ban apples. Suddenly we have far fewer apples and oranges still cost a lot. Lots pf people starve because they can't afford oranges. I think a better solution would be to tax apples that external cost, making apples more expensive. Some would switch to oranges with their strong preference for them. That apple tax, the money being taken from consumers of apples, could be applied to orange research. Tax apples, use that revenue to research cheaper oranges.
Tax CO2 which is predicted to have dire consequences for us, use that money to research ways to generate less CO2.