the only problem we have with CO2 is that there is an alarming LOW amount of it. Plants die at 170 ppm. If it gets that low there will be a massive extinction event....again. It has happened before.
CO2 can get VERY high with zero problems. Ever notice that greenhouse farmers enhance the air in their green houses with above 'normal' amounts of CO2? The plants grow better.

According to both the Greenland AND the Antarctic ice cores CO2 has been much higher in the past. Oddly enough increased temperature precedes high levels of CO2...it is not caused by it.

In the past the CO2 intensity was MUCH higher. Over a thousand PPM.

CO2 is NOT a problem.