Greenhouse gas

Greenhouse gases are components of the atmosphere that contribute to the greenhouse effect. Without the greenhouse effect the Earth would be uninhabitable; in its absence, the mean temperature of the earth would be about -19 °C (-2 °F, 254 K) rather than the present mean temperature of about 15 °C (59 °F, 288 K). Greenhouse gases include in the order of relative abundance water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The majority of greenhouse gases come mostly from natural sources but are also contributed to by human activity.
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A gas, such as carbon dioxide or methane, which contributes to potential climate change.

Any gas that absorbs infrared radiation in the atmosphere. Greenhouse gases include water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), halogenated fluorocarbons (HCFCs), ozone (O3), perfluorinated carbons (PFCs), and hydrofluorocarbons (HFCs). See carbon dioxide,  methane, nitrous oxide,  hydrochlorofluorocarbons, ozone,  hydrofluorocarbons, perfluorocarbons,  sulfur hexafluoride.

Noun
1. a gas that contributes to the greenhouse effect by absorbing infrared radiation
(synonym) greenhouse emission
(hypernym) gas
(hyponym) chlorofluorocarbon, CFC