24Earth climate tool
Greenhouse Gas Converter
Convert methane, nitrous oxide, and fluorinated gases into CO₂-equivalent using official IPCC Global Warming Potentials—with the time horizon and assessment report of your choice.
Your emission
Which gas, and how much?
Pick a gas, enter its mass, then choose the time horizon and IPCC methodology.
Private by design. Your amounts are calculated locally and are not saved.
COâ‚‚-equivalent
1 metric tonne of methane — fossil origin × GWP-100 of 29.8 equals
29.8 t COâ‚‚e
29,800 kg COâ‚‚e
Full detail
Conversion breakdown
Every element of the calculation, stated explicitly.
- Gas
- Methane — fossil origin CH₄
- Mass
- 1 metric tonne
- Conversion factor
- 29.8 GWP-100 (kg COâ‚‚e per kg CHâ‚„)
- Time horizon
- 100 years
- Resulting COâ‚‚e
- 29.8 t COâ‚‚e
- Source methodology
- IPCC AR6 (2021) IPCC Sixth Assessment Report, WG1 Tables 7.15 and 7.SM.7
Same gas, every methodology
How the choice changes the result
Your amount converted under each assessment report and horizon. The highlighted cells match your selection.
| Methodology | GWP-20 | COâ‚‚e (20-yr) | GWP-100 | COâ‚‚e (100-yr) |
|---|---|---|---|---|
| IPCC AR4 (2007) | — | — | — | — |
| IPCC AR5 (2013) | 85 | 85 t | 30 | 30 t |
| IPCC AR6 (2021) | 82.5 | 82.5 t | 29.8 | 29.8 t |
A dash means the report did not publish a GWP for that gas. Pick one methodology and horizon for any single inventory—mixing them within one total is not valid.
Why the horizon matters
One gas, two very different numbers
A GWP compares the energy a gas traps over a chosen period against the same mass of CO₂. Short-lived gases such as methane trap intense heat early and then decay, so their 20-year GWP is far higher than their 100-year GWP. Very long-lived gases such as SF₆ keep accumulating effect, so their GWP grows with the horizon.
- GWP-100The standard for national inventories, corporate reporting under the GHG Protocol, and the Paris Agreement rulebook.
- GWP-20Highlights near-term warming; often used when discussing rapid methane cuts. Not a substitute for GWP-100 in formal inventories.
- Methane splitSince AR5, fossil methane carries a slightly higher GWP than biogenic methane because its carbon adds new COâ‚‚ when it oxidises.
- No 500-year optionAR5 published no 500-year values, so this tool sticks to the two horizons all three reports share.
Transparent by design
Every factor we use
View the full GWP table
| Gas | Formula | AR4 (2007) | AR5 (2013) | AR6 (2021) | |||
|---|---|---|---|---|---|---|---|
| GWP-20 | GWP-100 | GWP-20 | GWP-100 | GWP-20 | GWP-100 | ||
| Carbon dioxide | COâ‚‚ | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| Methane — fossil | CHâ‚„ | — | — | 85.0 | 30.0 | 82.5 | 29.8 |
| Methane — non-fossil | CH₄ | 72.0 | 25.0 | 84.0 | 28.0 | 79.7 | 27 |
| Nitrous oxide | Nâ‚‚O | 289.0 | 298.0 | 264.0 | 265.0 | 273.0 | 273.0 |
| HFC-23 | CHF₃ | 12,000.0 | 14,800.0 | 10,800.0 | 12,400.0 | 12,400.0 | 14,600.0 |
| HFC-32 | CHâ‚‚Fâ‚‚ | 2,330.0 | 675.0 | 2,430.0 | 677.0 | 2,690.0 | 771.0 |
| HFC-125 | CHF₂CF₃ | 6,350.0 | 3,500.0 | 6,090.0 | 3,170.0 | 6,740.0 | 3,740.0 |
| HFC-134a | CH₂FCF₃ | 3,830.0 | 1,430.0 | 3,710.0 | 1,300.0 | 4,140.0 | 1,530.0 |
| HFC-143a | CH₃CF₃ | 5,890.0 | 4,470.0 | 6,940.0 | 4,800.0 | 7,840.0 | 5,810.0 |
| HFC-152a | CH₃CHF₂ | 437.0 | 124.0 | 506.0 | 138.0 | 591.0 | 164.0 |
| PFC-14 | CFâ‚„ | 5,210.0 | 7,390.0 | 4,880.0 | 6,630.0 | 5,300.0 | 7,380.0 |
| PFC-116 | C₂F₆ | 8,630.0 | 12,200.0 | 8,210.0 | 11,100.0 | 8,940.0 | 12,400.0 |
| Sulfur hexafluoride | SF₆ | 16,300.0 | 22,800.0 | 17,500.0 | 23,500.0 | 18,300.0 | 25,200.0 |
| Nitrogen trifluoride | NF₃ | 12,300.0 | 17,200.0 | 12,800.0 | 16,100.0 | 13,400.0 | 17,400.0 |
Methane: AR6 values follow WG1 Table 7.15, which separates fossil from non-fossil methane. AR5 values follow Table 8.A.1 with its fossil adjustment (+1 GWP-20, +2 GWP-100). AR4 published a single methane value with no fossil split. All values include climate–carbon feedbacks as published.
Fluorinated gases: The list covers the most common HFCs, PFCs, SF₆, and NF₃. Hundreds more fluorinated species exist; for gases not listed here, consult the IPCC tables linked below.
GWP values carry substantial scientific uncertainty (roughly ±30–40% for methane) and are periodically revised between assessment reports. CO₂-equivalence compares cumulative energy trapped over the chosen horizon; it does not capture the timing of warming. Use one methodology consistently within any single inventory, and check which report your reporting scheme mandates—many programmes still require AR5 or AR4 values.
