Home Green Cars 2 : Greenhouse Gases 2.2 The Six Greenhouse Gases The Six Greenhouse Gases  2.2  The Six Greenhouse Gases The three most important greenhouse gases, in order of significance, are: Carbon Dioxide (CO2): Mainly from burning fossil fuels. Methane (CH4): The result of natural gas processing, livestock operations, solid waste dumps and pipeline leaks. Nitrous Oxide (N20): Mainly from fertiliser use. The other three gases are: (1) Hydrofluorocarbons (HFCs). (2) Perfluorocarbons (PFCs). (3) Sulphur Hexafluoride (SF6). Note: Chlorofluorocarbons (CFCs) are covered by the 1987 Montreal Protocol.   [ Back ]