Nature Enthusiasts

we should start trying to come to terms with knowing that it is our turn to join them

That's just called "death". Everything that lives today is descended from an organism that existed before it. The idea that humans would just... stop existing, rather than producing variants that were more acclimated to the subsequent iteration of earth's biome seems unlikely, particularly given how rapidly we've learned to adapt to changing ecological conditions.

Given that humans - as a species - survived the Ice Age, they'll likely survive the Heat Age in some form or another.