Exactly. The world changed - animals and plants died out but...

Exactly. The world changed - animals and plants died out but there were winners as well. It's called adaptation. At present we are trying to stop climate change as we are being told another 1.5° is the end.
It is not the end - the world will adapt to warmer climates. Sure some life forms will die out and others will benefit but that is the way it works.
In my opinion the billions being spent on combatting climate change will not have a significant effect on global warming.
A final thought - what if global warming is mostly a natural phenonmenum as happened 11,000 years ago???
.