From your Wikipedia link:
Main article: Greenhouse gas
By their percentage contribution to the greenhouse effect on Earth the four major gases are:
water vapor, 36–70%
carbon dioxide, 9–26%
The major non-gas contributor to the Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on radiative properties of the atmosphere."
This says that CO2 may be as much as 26% of the total Green house gases.
All Greenhouse gases comprise about 5% of the atmosphere.
26% of 5% is 1.3% of the total atmosphere.
That is 13,000 ppm. This is higher than CO2 has been in about a billion years.
The actual concentration of CO2 is about 400 ppm; .0004% of the atmosphere.
Also, in the real world, water vapor comprises about 95% of all green house gases.