Co2 is a greenhouse gas ofcourse,and it does add a small amount of warming.But it has not been shown that the .7C rise in the last century is attributable to CO2.It is simply not a strong enough greenhouse gas.CO2???s radiative effect is,as you know,logarithmic and so has less of an effect for each given volume that is put into the atmosphere.The majority of the radiative effect of CO2 is already