Altogether there are six different greenhouse gases that contribute to global warming in different ways. The best known greenhouse gas is carbon dioxide (CO2). Other greenhouse gases include methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6) and nitrogen trifluoride (NF3).The degree to which each gas contributes to global warming is demonstrated by its different potentials. Methane, for example, has an impact on our climate many times greater than that of CO2. For comparability purposes, all greenhouse gases are usually converted into CO2 equivalents.