This is correct. Just so you know when you run into these people, 'greenhouse gases' are based on the idea of 'reemission', that is: they absorb in the same bands that they emit in, which, to small minds, could create a runaway effect (this runs afoul of physics). Anyway, **any thermal spectrograph of the atmosphere is entirely driven by water; [see this paper, figure 6.3 on page five.](http://irina.eas.gatech.edu/EAS8803_Fall2009/Lec6.pdf)** The area under the H2O graph is over an order of magnitude larger than that of the CO2.