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CO2 equivalents
Most charts and tables in this emissions section of our website convert all greenhouse gase emissions (GHG) into CO2 equivalents so they can be compared.
Each greenhouse gas (GHG) has a different global warming potential (GWP) and persists for a different length of time in the atmosphere. The three gases of carbon dioxide (CO2), methane (NH4), and nitrous oxide (N2O) (along with water vapour) are the main greenhouse gases:
- carbon dioxide (CO2) - 1 x
- methane (NH4) - 21 x
- nitrous oxide (N2O) - 310 x
The greenhouse effect of methane is 21 times more powerful than carbon dioxide. Nitrous oxide is 310 times more powerful than carbon dioxide. (1)
Water vapour is not considered to be a cause of man-made global warming because it does not persist in the atmosphere for more than a few days.
There are other greenhouse gases which have far greater global warming potential (GWP) but are much less prevalent. These are sulphur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs).
There are a wide variety of uses for SF6, HFCs, and PFCs but they have been most commonly used as refrigerants and for fire suppression. Many of these compounds also have a depleting effect on ozone in the upper atmosphere.
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GWP table
The following table shows the global warming potentials (GWP) for all of the greenhouse gases reported by the
United Nations Framework Convention on Climate Change (UNFCCC)
.
|
Greenhouse Gas |
Formula |
100 year GWP |
| 1. |
Carbon dioxide |
CO2 |
1 |
| 2. |
Methane |
CH4 |
21 |
| 3. |
Nitrous oxide |
N2O |
310 |
| 4. |
Sulphur hexafluoride |
SF6 |
23,900 |
| |
Hydrofluorocarbons (HFCs) |
| 5. |
HFC-23 |
CHF3 |
11,700 |
| 6. |
HFC-32 |
CH2F2 |
650 |
| 7. |
HFC-41 |
CH3F |
150 |
| 8. |
HFC-43-10mee |
C5H2F10 |
1,300 |
| 9. |
HFC-125 |
C2HF5 |
2,800 |
| 10. |
HFC-134 |
C2H2F4
(Structure: CHF2CHF2) |
1,000 |
| 11. |
HFC-134a |
C2H2F4
(Structure: CH2FCF3) |
1,300 |
| 12. |
HFC-143 |
C2H3F3
(Structure: CHF2CH2F) |
300 |
| 13. |
HFC-143a |
C2H3F3
(Structure: CF3CH3) |
3,800 |
| 14. |
HFC-152a |
C2H4F2
(Structure: CH3CHF2) |
140 |
| 15. |
HFC-227ea |
C3HF7 |
2,900 |
| 16. |
HFC-236fa |
C3H2F6 |
6,300 |
| 17. |
HFC-245ca |
C3H3F5 |
560 |
| |
Perfluorocarbons (PFCs) |
| 18. |
Perfluoromethane |
CF4 |
6,500 |
| 19. |
Perfluoroethane |
C2F6 |
9,200 |
| 20. |
Perfluoropropane |
C3F8 |
7,000 |
| 21. |
Perfluorobutane |
C4F10 |
7,000 |
| 22. |
Perfluorocyclobutane |
c-C4F8 |
8,700 |
| 23. |
Perfluoropentane |
C5F12 |
7,500 |
| 24. |
Perfluorohexane |
C6F14 |
7,400 |
