Definitions for "Greenhouse gases"
Gases that accumulate in the Earth's atmosphere and trap heat. Some occur naturally, such as water vapour, ozone, carbon dioxide, methane, nitrous oxide and other trace compounds, while others are human-made. There are six GHGs covered under the Kyoto Protocol — carbon dioxide (CO2), methane (CH4) and nitrous oxide (N20), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulphur hexafluoride (SF6). (Source: Government of Canada Climate Change Site, Glossary of Climate Change Terms)
gases, such as carbon dioxide and methane, that tend to trap heat radiating from the Earth's surface, thus causing warming in the lower atmosphere. The major GHGs causing climate change are carbon dioxide (CO), methane (CH), and nitrous oxide (N O). The Kyoto Protocol also addresses hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), ans sulphur hexafluoride (SF).
apart from our old friend carbon dioxide, the main anthropogenic ones are methane and nitrous oxide.
Keywords:  climate, change, see
(see climate change).