Earth's greenhouse gases trap heat in the atmosphere and warm the planet. The main gases responsible for the greenhouse effect include carbon dioxide, methane, nitrous oxide, and water vapour (which all occur naturally), and fluorinated gases like CFCs (which are synthetic).

Sulphur dioxide does not absorb and trap infrared radiation, but it is considered an indirect greenhouse gas because when coupled with elemental carbon, it forms aerosols. Hence, sulphur dioxide is not a greenhouse gas.