Greenhouse Gas
Gases in the Earth's atmosphere that trap heat — including CO2, CH4, N2O, and fluorinated gases. Corporate GHG accounting covers the six gases defined by the Kyoto Protocol.
Greenhouse gases (GHGs) are atmospheric gases that absorb and re-emit infrared radiation, trapping heat in the Earth’s atmosphere. The primary GHGs relevant to corporate carbon accounting are defined by the Kyoto Protocol and covered by GHG Protocol: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6), and nitrogen trifluoride (NF3).
The six Kyoto Protocol GHGs
| Gas | Symbol | Primary Source in Manufacturing | GWP (AR5, 100yr) |
|---|---|---|---|
| Carbon dioxide | CO2 | Fossil fuel combustion | 1 |
| Methane | CH4 | ETP, biomass combustion | 28 |
| Nitrous oxide | N2O | Combustion, processes | 265 |
| HFCs | Various | Refrigerant leakage | 1,430–14,800 |
| PFCs | Various | Electronics (rare in mfg) | 7,390–12,200 |
| SF6 | SF6 | Electrical switchgear | 23,500 |
CO2 vs CO2 equivalent
CO2 equivalent (CO2e) is the single unit used to aggregate all GHGs into a comparable measure, weighted by their Global Warming Potential (GWP). A company’s total GHG emissions are reported as tCO2e — the sum of all gases converted to their CO2 equivalent using IPCC GWP values.
Which gases must be reported?
GHG Protocol and BRSR require all six Kyoto Protocol gases to be reported where material. For most Indian manufacturers, CO2 from stationary combustion dominates (typically 85–95% of total). HFC refrigerant leakage is the most commonly missed non-CO2 source.