It has the potential to disrupt the ability of our planet to cool itself.
Therefore, the average temperature of our planet should be higher than it would have been in the absence of CO2 (and other greenhouse gasses, such as water vapor).
Infrared gas lab spectroscopy experiments suggest CO2 would cause mild warming in the the troposphere.
The lab experiments are done in a closed system, in artificially dried air.
The actual effect of CO2 in the atmosphere can't be measured, because:
(1) The water vapor there (a much more powerful greenhouse gas) is not constant, and,
(2) Natural causes of climate change can't be separated from any effects of man made CO2.
No matter what the exact effects of CO2 are in the atmosphere, there has been mild, harmless warming, and greening of our planet, since the mid-1970s -- both good news.
CO2 is a greenhouse gas.
It is likely to affect our planet's ability to cool itself.
There is a little real science behind the global warming predictions.
But there is no real science to support a coming global warming crisis, inaccurately predicted since the late 1950s.
The imaginary coming global warming crisis is unjustified speculation and fearmongering.