Gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and re-emit infrared radiation.
(UNFCCC, 1992)
A gas that absorbs radiation at specific (infrared) wavelengths of the spectrum emitted by the Earth’s surface and by clouds. At altitudes cooler than surface temperature, these gases emit infrared radiation. The net effect is a local trapping of part of the absorbed energy and a tendency to warm the planet's surface.
Water vapour (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4) and ozone (O3) are the principal greenhouse gases in the Earth’s atmosphere.
(Giving wings to emission trading, CE Delft, 2005)
See also Kyoto GHGs.
=> Glossary