Earth’s Energy Balance

Sunlight in, heat out

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Stefan–Boltzmann: radiated power per m² is $\sigma T^4$.
• Earth absorbs (1 − albedo) × S/4. The factor 4 is sphere area ÷ disc area.
• Balance gives 255 K, but the surface is 288 K: the greenhouse effect makes up the gap.

Steps

1. In equals out
2. Divide by four
3. Earth’s temperature
4. Check the number
5. What Earth absorbs
6. Doubling CO₂