The mineral record shows CO2 bouncing along at the minimumu for photosynthesis – pants AND bacteria cinvert excess CO2 into biomass.
Which is the reason CO2 levels in the free air are at a preindutrial 2ppm. 200Ppm – nuclear fiction.
The in an ice age the levels double. The Jurassic had 3 ice-ages, one lasting 650 million years – with free CO2 at 8ppm. So it obviously does NOT warm the weather.
Deep sea bacterial alos sink CO2 to 2ppm.