Agreenhouse gas(sometimes abbreviatedGHG) is a gas in an atmosphere thatabsorbsandemitsradiation within thethermal infraredrange. This process is the fundamental cause of thegreenhouse effect.[1]The primary greenhouse gases in theEarth's atmospherearewater vapor,carbon dioxide,methane,nitrous oxide, andozone. In theSolar System, the atmospheres ofVenus,Mars, andTitanalso contain gases that cause greenhouse effects. Greenhouse gases greatly affect the temperature of theEarth; without them, Earth's surface would average about 33C (59F) colder than the present average of14 C(57F)
