Energy balance in the atmosphere

Received energy = Emitted energy

The earth receives energy from the sun in form of solar radiation.The earth emits energy in the form of heat radiation. There is a balance between insolation and radiance.

When the relation between emitted energy and received energy is unbalanced, the global temperature will change. The earth's temperature increases when the earth receives more energy from the sun in the form of solar radiation, than the energy the earth emits in the form of heat radiation. However, when the earth’s temperature rises, the heat radiation emitted from the earth rises as well. Therefore, at one point there is a new balance between insolation and radiance.

Furthermore, at this point the earth emits as much energy as it receives from the sun.

The earth's temperature decreases when the earth emits more energy than it receives from the sun. However the earth will emit less energy as the temperature decreases which then again stabilizes the energy balance.