CO2 is a greenhouse gas.
By definition, in isolation it has a net warming effect - but is subject to interactions with many other variables and systems in ways that we are yet to fathom.
This thread is filled with info from the start explaining how much of it is in the atmosphere, and how little we know in terms of its exact contribution to climate, so taking two quotes out of context contrary to someones stated position is casting a spurious assertion (Hmmm, pattern forming here). I do this all the time, but Rod has played a pretty straight bat.
In terms of AGW Theory, the main issue in this thread, there is NO evidence proving a causal relationship between anthropogenic CO2 emissions and the measured 0.7 degree celsius "statisticallly averaged globally measured" warming over the last 150 years.