Climate Model Interpreter Calculator

Temperature and radiative forcing from greenhouse gas concentrations using Myhre et al. formulas.

CO2 concentration (ppm)

Pre-industrial CO2 (ppm)

Climate sensitivity (°C/doubling)

CH4 concentration (ppb)

Pre-industrial CH4 (ppb)

N2O concentration (ppb)

Pre-industrial N2O (ppb)

Tab to move between fields

Equilibrium warming (°C)

2.42

Transient warming (°C)1.45

Total radiative forcing (W/m²)3

CO2 forcing (W/m²)2.17

CH4 forcing (W/m²)0.6

N2O forcing (W/m²)0.23

Committed warming remaining (°C)0.97

CO2 × pre-industrial1.5

How to Use This Calculator

Enter current CO₂ concentration (ppm), pre-industrial CO₂ baseline, and equilibrium climate sensitivity (°C/doubling).
Add CH₄ (ppb), N₂O (ppb), and their pre-industrial baselines.
Review Equilibrium Warming (°C), Transient Warming (°C), and Total Radiative Forcing (W/m²).
Compare equilibrium vs. transient warming — the committed warming is often larger than what we currently observe.

How the result changes with Pre-industrial CO2 (ppm)

CO2 concentration (ppm): Atmospheric CO2 in parts per million. Current level ~420 ppm (2024).
Pre-industrial CO2 (ppm): Pre-industrial CO2 baseline, typically 280 ppm.
Climate sensitivity (°C/doubling): Equilibrium climate sensitivity. IPCC AR6 best estimate is 3°C.
CH4 concentration (ppb): Atmospheric methane in parts per billion. Current ~1,900 ppb.
Pre-industrial CH4 (ppb): Pre-industrial methane baseline, typically 722 ppb.
N2O concentration (ppb): Atmospheric nitrous oxide. Current ~335 ppb.
Pre-industrial N2O (ppb): Pre-industrial N2O baseline, typically 270 ppb.

Equilibrium warming (°C): Long-term temperature rise once the climate system fully equilibrates.
Transient warming (°C): Near-term warming accounting for ocean thermal inertia (~60% of equilibrium).
Total radiative forcing (W/m²): Net energy imbalance from all specified greenhouse gases.
CO2 forcing (W/m²): Radiative forcing from CO2 using ΔF = 5.35 × ln(C/C₀).
CH4 forcing (W/m²): Radiative forcing from methane.
N2O forcing (W/m²): Radiative forcing from nitrous oxide.
Committed warming remaining (°C): Additional warming locked in but not yet realized due to ocean lag.
CO2 × pre-industrial: Current CO2 as a multiple of pre-industrial levels.

Identify Input Parameters
4 parameters
CO2 concentration (ppm) = 420, Pre-industrial CO2 (ppm) = 280, Climate sensitivity (°C/doubling) = 3, CH4 concentration (ppb) = 1900 = 7 input(s) provided
Calculate Equilibrium warming
Equilibrium warming = lambda * totalForcing
2.42 = 2.42
Calculate Transient warming
Transient warming = equilibriumWarming * 0.6
1.45 = 1.45
Calculate Total radiative forcing
Total radiative forcing = forcingCO2 + forcingCH4 + forcingN2O
2.996 = 2.996