- GWP is a relative scale
- compares the gas to an equivalent of CO2
- GWP for CO2 is (by convention) equal to 1
- Anthropogenic GHG covered by NGERs & their GWP:
| carbon dioxide, CO2 | (CO2) |
| methane, CH4 | (CO2 x 25) |
| nitrous oxide, N2O | (CO2 x 295) |
| sulphur hexafluoride, SF6 | (CO2 x 23,900) |
| hydrofluorocarbons , CnHxF(2n+2 – x) | (CO2 x 140 – 11,700) |
| perfluorocarbons , CnF (2n+ 2)(0 < n < 7) | (CO2 x 6,500 – 9,200) |
Reference: August 2009 API Compendium Table3.1
- GHG emissions associated with energy use (combustion emissions) are: CO2 , CH4 and N2O