Skeptical Scientists Lambast UN Climate Meeting

[Xiahou]

CO2 in the atmosphere acts just like... a greenhouse. Disprove that greenhouses work by trapping in heat and you then have a factual basis to disprove CO2 acting as a greenhouse gas.

No, it works nothing like a greenhouse. Even those that support AGW know that the "greenhouse effect" is a misnomer. Real greenhouses work by preventing convective heat loss, whereas the atmospheric greenhouse effect is claimed to reduce radiative heat loss.

edit:
Wikipedia
Junkscience provides (imo) a better explanation.

Does the Earth's atmosphere primarily behave like an actual greenhouse?

No. The term "greenhouse effect" is unfortunate since it results in a false impression of the activity of so-called "greenhouse gases." An actual greenhouse works as a physical barrier to convection (the transfer of heat by currents in a fluid) while the atmosphere really facilitates convection so the impression of actual greenhouse-like activity in the Earth's atmosphere is incorrect.