Greenhouse effect: simplified planetary energy balance (Incoming solar power absorbed by Earth–atmosphere system balances outgoing IR emission)
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Incoming solar power absorbed by Earth–atmosphere system balances outgoing IR emission: (1−α)S/4 = εσT⁴ in the simple one-layer model (α albedo, S solar constant, ε emissivity, σ Stefan–Boltzmann, T effective radiating temperature).
What each symbol means
| Symbol | What it stands for |
|---|---|
| S | Solar constant (~1361 W/m² at 1 AU — values vary slightly by source) |
| T | Effective equilibrium temperature |
| α | Planetary albedo (fraction reflected) |
| ε | Effective atmospheric emissivity / IR trapping parameter in simplified model |
| σ | Stefan–Boltzmann constant |
When to use this
Highly idealized global average model for intuition; real climate has spectral windows and dynamics.