Please correct me if I'm wrong. The amplitudes of co2 ppm seem to always have been within a certain band though, topping out at 300ppm. Right now, we're at 420ppm and increasing what looks like exponentially. [0]
I'm not saying humans won't be fine but we've never been so dependent on the stability of the climate before. People will die, get displaced, suffer economically, etc as far as I understand.
It was over 4000ppm during the Cambrian period 500m years ago, then down to about where it is today in the Carboniferious period, during the 60 million year period where trees evolved to make wood, but nothing had evolved to eat it yet, so dead trees literally just piled up for 60 million years. Then during the Mezozoic it went up into the 2000s again, lots of dino farts or something? Then back under 1000 again and dropping until the last 100 years or so.
Of course, there were also mass migrations and extinctions as the environment changed so radically, which seems like something that would be nice to avoid.
> On the positive, the earth has been much warmer and much colder, and has had more carbon and less carbon in the atmosphere.
the way I read it suggesting that it'll be fine. But it won't be, if co2 increased to 4000 ppm quickly enough, humans would not be fine. There were no humans during the time you were describing.
It's not but it's also not much less time than what we consider "humans" to have been around and we're talking about co2 in the atmosphere in the context of whether humans will be fine or not.
I'm not saying humans won't be fine but we've never been so dependent on the stability of the climate before. People will die, get displaced, suffer economically, etc as far as I understand.
[0] https://www.climate.gov/news-features/understanding-climate/...