But there have been way higher atmospheric carbon dioxide levels historically, and those have largely coincided with plant and animal life climaxing. See the Jurassic.

> But there have been way higher atmospheric carbon dioxide levels historically

Historically? In written human history?

If we're talking the state of the planet throughout the past 4 billion odd years of existence, it once had no breathable atmosphere and had a stretch with a largely molten surface, and got smacked up hard when the moon was spun off.

None of these things are relevant to the planets near future as a direct result of human induced changes of the past century and a half.

"History" is generally used to mean when humans were around writing stuff down. And no, CO2 levels have never been this high during the entire history of human civilization, and likely the entire existence of Homo sapiens

I believe those followed global extinction events thanks to large scale volcanic activity over long enough time frames to change the climate. Life did adapt, the life that survived. I'm not sure we want to run that experiment on human civilization.