Chapter 6 of 10All chapters
Chapter 6 of 10
The greenhouse effect
Why the planet is habitable.
How it works
Sunlight passes through the atmosphere and warms the surface, which radiates heat back as infrared. Certain gases absorb that infrared and re-emit it, some of it downwards.
- Without any greenhouse effect the average surface would be about minus 18 degrees Celsius.
- Water vapour, carbon dioxide and methane are the main contributors.
Not a new idea
The physics was worked out in the nineteenth century and the absorption spectra are measured in laboratories. It is one of the older and better established parts of atmospheric science.