How does the atmosphere insulate earth?

Sagot :

The atmosphere insulates the earth by keeping the sun's warmth contained. 
There is a natural greenhouse effect, supported by the water cycle and the carbon cycle, that ensures that the earth is kept insulated and warm. Greenhouse gases capture and hold the sun's infra-red radiation from the surface of the earth. These gases then radiate the heat out in all directions, including back down to the surface of the earth.