(c) The six main greenhouse gases are –
• Carbon dioxide (CO2);
• Methane (CH4);
• Nitrous oxide (N2O);
• Hydrofluorocarbons (HFCs);
• Perfluorocarbons (PFCs); and
• Sulphur hexafluoride (SF6).
Methane (CH4) is the second most important greenhouse gas. CH4 is more potent than CO2 because the radiative forcing produced per molecule is greater. In addition, the infrared window is less saturated in the range of wavelengths of radiation absorbed by CH4, so more molecules may fill in the region.