Climate change is indeed the perfect example, because if we bothered to do anything about it on a societal scale instead of saying "oh well, use paper straws I guess" we'd have had a chance at stopping it and it wouldn't be so apocalyptic.

But instead, we've consistently done very little because it's always seemed too far away to matter, but by the time we start to feel the effects it's basically too late. Realistically, I don't think it's about anxiety necessarily, I think people just don't want to change their way of life. It seems like everything might work out, and little changes like carbon taxes and paper straws might mean we can keep going normally and feeding the consumerism machine like normal while driving everywhere.

As an aside, the heat death of the universe is utterly irrelevant, we'll be dead long before then. And if not, then that will be such a glorious existence for humanity that I'd be happy to die with the universe itself. I just would rather not die stuck on our own rock, choking on our own emissions that we refused to do anything about.