I agree with you. I am 50, no children.
I have spent last 10 years travelling, sailing the ocean, hiking in jungles, diving in the reefs that would be extinct soon. I live in a climate where some moderate warming will make more pleasant.
I do not care what will happen beyond 20 years ahead. Maybe even less.
So why would I inconvinience myself? Why worry? People will get exactly what they deserve.
On the other hand somehow it doesn't seem right.