Climate Feedback & Sensitivity Lab

Forcing

CO₂ radiative forcing ΔF 3.7 W/m²

Feedback strengths (W/m²/K)

Water vapor + lapse rate 1.15

Ice–albedo 0.30

Cloud 0.45

Live readout

Global ΔT

0.00 °C

Model time

0 yr

Net feedback λ

1.75

Equilibrium ΔT_eq

2.11 °C

How it works

This is a zero-dimensional energy-balance model — the same accounting a GCM/ESM does at every grid cell, reduced to a single global box with an ocean-mixed-layer heat capacity C:

C · dT/dt = ΔF − λ·T
λ = λ_planck − (λ_wv + λ_ice + λ_cloud)
ΔT_eq = ΔF / λ   (as t → ∞, dT/dt → 0)

λ_planck ≈ 3.2 W/m²/K — the stabilizing blackbody response (fixed here): a warmer surface radiates more infrared, pulling T back down.
Water vapor + lapse rate, ice–albedo, cloud — positive feedbacks that subtract from λ_planck. A warmer atmosphere holds more water vapor (itself a greenhouse gas), melts reflective ice/snow, and shifts cloud cover — each further reduces the net damping.
ΔF — the radiative forcing being tested; 3.7 W/m² is the standard forcing from a CO₂ doubling.
If the sliders push total feedback strength past λ_planck, λ ≤ 0 and the box no longer has a stable equilibrium — the model flags this as a runaway regime, mirroring why ESMs must keep λ positive for a stable solution.
Each cube on the globe is a coarse "grid cell": its color follows the same global ΔT but is locally amplified toward the poles in proportion to the ice–albedo slider — a simplified stand-in for the polar-amplification parameterization real GCMs compute per cell.

⚠ Feedbacks exceed the Planck response — no stable equilibrium (runaway regime)

Local temperature anomaly (cold → hot)

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