About 95% or "greenhouse gas" in the atmosphere is.... water vapor. CO2 is a minute fraction of greenhouse gasses and a much much much more minute fraction of our atmosphere. The models that predict increasing temperatures due to rising CO2 rely on the theory that CO2 will have a multiplier effect on water vapor. This hasn't panned out, which is why so many models have so seriously missed the mark on predicting temperture increase.
With the warmers there's always another study they can deflect to, always something to quibble over, always a new "adjusted" data set, but the fact remains that the science is far from settled and nobody knows with anything close to certainty how much increasing CO2 will increase temperture, let alone whether that will be a net negative.