SSP Climate Scenario Comparator — 2D Phase Portrait

SSP Scenario

Compare all four at once

Model Parameters

Climate sensitivity ECS 3.0 °C

Ocean heat uptake κ 0.70 W/m²/K

Mitigation pace τ 35 yr

Playhead year 2020

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Radiative forcing F(t)

2.20 W/m²

Surface ΔT₁

0.00 °C

Deep-ocean ΔT₂ (thermal lag)

0.00 °C

How it works

Same two-layer energy-balance model (EBM) as the 3D version, but drawn natively in 2D instead of as a bar landscape: a time-series chart of F(t), T₁(t), T₂(t) on top, and a phase-space portrait below plotting deep-ocean ΔT₂ against surface ΔT₁ as the system evolves — the diagonal is the T₁=T₂ equilibrium line, and the curve bows below it while the deep ocean lags behind.

F(t) = F₀ + (F_target − F₀) · (1 − e^(−(t−2020)/τ))
C₁ dT₁/dt = F(t) − λT₁ − κ(T₁−T₂)
C₂ dT₂/dt = κ(T₁−T₂)
λ = F₂ₓ / ECS   (F₂ₓ ≈ 3.8 W/m² per CO₂ doubling)

ECS — equilibrium climate sensitivity: equilibrium warming per CO₂ doubling. Higher ECS means a smaller λ, so the same forcing produces more warming.
κ — ocean heat uptake efficiency. A larger κ pulls more heat into the deep ocean, damping and delaying surface warming.
τ — how many years it takes forcing to close most of the gap to its 2100 target.
The phase-space curve's distance below the T₁=T₂ diagonal is a direct visual measure of thermal disequilibrium — how far the climate system still is from its eventual steady state.