I've been writing a Cli-Fi/Speculative Fiction novel for years. I kept facing one problem, though: all the research I was doing about climate change was really depressing. In some cases, I would project 50 years in the future, only to have my "speculation" unfold in the news a few months later.
This constant reminder of our fragility was untenable, and I was losing my mind. So instead of looking at the near future–which is undeniably bleak–I started researching the entire arc of life on earth.
This was the first mass extinction, known colloquially as "Snowball Earth" up until the third mass extinction, the Permian-Triassic.
The extinctions were important, not because of the massive die-offs, but because of what arose from the catastrophes. I highlighted the extinctions in color to differentiate them from the eras.
Creature-wise, things are starting to look a lot more familiar after this extinction event. Pterosaurs and plesiosaurs are making the rounds, as well as my personal favorite, the stegosaurs.