the only gas with global warming potential?
No, there are a multitude of gasses that contribute to global warming, and therefore are greenhouse gasses amongst them; we have nitrous oxide (N2O), methane (CH4) and ozone (O3). Also, man has synthesized non-natural compounds, such as Per fluorocarbons gasses (CFCs, HFCs, PFCs and SF6), which have a high global warming potential. It should be noted that not all these gasses are included in the Kyoto Protocol.