The level of atmospheric CO2 has nothing to do with causing/changing/controlling our climate.
The entire atmosphere has nothing to do with causing/changing/controlling our climate.
Anytime folks talk about a system of “warmer” or “cooler”, they are talking thermodynamics.
Ergo, climate is the thermodynamic system that causes our weather. Such a definition breaks the circular description of “climate is the weather of an area over a period of time”, and “weather is the atmospheric events caused by climate”. And around and around we go.
When climate is properly understood to be the thermodynamic system that drives the weather, the circular dependency is resolved, and climate can be described accurately as the system of solar heating of the earth’s surface that is partially ameliorated by the oceans’ currents that help distribute heat from the tropical regions towards the polar regions. Etc.
From what I have learned about CO2 in the atmosphere, there COULD be a change in CO2 in the atmosphere that would affect us, but it would require a very high or a very low level of CO2; much more than we have ever known.