Methane GWP Horizon Comparison Calculator Formula
Understand the math behind the methane gwp horizon comparison calculator. Each variable explained with a worked example.
Formulas Used
CO2e (20-year horizon)
co2e_20yr = methane_kg * gwp_20yrCO2e (100-year horizon)
co2e_100yr = methane_kg * gwp_100yrCO2e (100-year, tonnes)
co2e_100yr_tonnes = methane_kg * gwp_100yr / 1000Variables
| Variable | Description | Default |
|---|---|---|
methane_kg | Methane Emitted(kg) | 500 |
gwp_20yr | GWP-20 for Methane | 80 |
gwp_100yr | GWP-100 for Methane | 28 |
How It Works
Methane to CO2 Equivalence
Methane (CH4) is a potent greenhouse gas that traps far more heat per molecule than CO2 but breaks down faster in the atmosphere.
Formula
CO2-Equivalent = Methane Mass (kg) x GWP Factor
The 20-year GWP of methane is about 80, reflecting its intense short-term warming. The 100-year GWP is about 28, accounting for atmospheric breakdown. The choice of time horizon significantly affects policy priorities.
Worked Example
A landfill releases 500 kg of methane per year.
methane_kg = 500gwp_20yr = 80gwp_100yr = 28
- 0120-year CO2e = 500 x 80 = 40,000 kg CO2e
- 02100-year CO2e = 500 x 28 = 14,000 kg CO2e
- 03In tonnes (100-yr): 14,000 / 1,000 = 14 tonnes CO2e
Ready to run the numbers?
Open Methane GWP Horizon Comparison Calculator