Stages of the natural greenhouse effect

1. About 50% of the sun's incoming short-wave radiation is absorbed by the Earth's surface, while 20% is absorbed by the atmosphere and 30% is reflected into space by clouds and the Earth's surface. 2. The absorbed short-wave radiation warms the Earth's surface. 3. The warm Earth emits long-wave infra-red radiation back into the atmosphere. 4. Greenhouse gases absorb some of this outgoing long-wave radiation, heating the atmosphere or reflecting it back to the Earth's surface.