Earth Energy Budget and Greenhouse Effect

Earth receives mainly shortwave solar radiation. Some incoming energy is: reflected by clouds, atmosphere and surface; absorbed by the atmosphere; absorbed by the surface. Earth emits energy mainly as infrared radiation. Important greenhouse gases include: water vapour; carbon dioxide; methane; * nitrous oxide. These gases absorb and re-emit infrared radiation at particular wavelengths. The natural greenhouse effect helps keep Earth's surface warmer than it would be without an infrared-active atmosphere.

For a simple idealized radiating body: **PA = σT⁴ Stefan-Boltzmann law. A simple planetary balance idea is: absorbed solar energy ≈ outgoing infrared energy** at long-term equilibrium.