Atmosphere, Heat, and the Ozone Layer

The atmosphere helps maintain habitable conditions, but it does not act simply as thermal insulation: greenhouse gases absorb and emit infrared heat, while clouds, water vapor, and the surface contribute to a complex energy balance. The natural greenhouse effect makes Earth’s average surface temperature substantially warmer than it would be without it. Stratospheric ozone absorbs much of the Sun’s harmful ultraviolet radiation. Saying it protects us from “excessive sunlight” is too broad: ozone is especially important for UV, not all sunlight.