Except it is the case in the joke I was replying to:

> "What if it's a big hoax and we create a better world for nothing?" https://en.m.wikipedia.org/wiki/What_if_it%27s_a_big_hoax_an...

This joke asserts that climate change mitigation measures would be justified even if climate change was a hoax. And that joke only works if you assume that those measures are free, or at least very cheap.