Earth's Energy Budget & Radiative Forcing

Greenhouse gas concentrations, logarithmic forcing, and equilibrium temperature

CO₂ (ppm) 420 ppm

CH₄ (ppb) 1900 ppb

N₂O (ppb) 335 ppb

Solar Constant (S₀) 1361 W/m²

Surface Albedo (α) 0.30

Climate Sensitivity (λ) 0.80 K/(W/m²)

+0.0 W/m²

CO₂ Forcing

+0.0 W/m²

CH₄ Forcing

+0.0 W/m²

N₂O Forcing

+0.0 W/m²

Total RF

+0.0°C

ΔT Equilibrium

288K

T_surface

CO₂ forcing is logarithmic: ΔF = 5.35·ln(C/C₀) W/m². Doubling CO₂ gives ~3.7 W/m² forcing. Equilibrium warming: ΔT = λ·ΔF, where λ is climate sensitivity (ECS ~3°C per doubling = λ≈0.8). Pre-industrial reference: CO₂ = 280 ppm, CH₄ = 700 ppb, N₂O = 270 ppb. Current (2024) CO₂ forcing ≈ +2.3 W/m² above pre-industrial.