The amount of energy from the sun that reaches the earth is 15,000 times greater than the energy demand of the entire human race. It heats up our planet so that biological life as we know it in the area near the surface is possible. It is also responsible for the barometric differences in the atmosphere, which create the winds.
The water circulation on earth is driven by solar energy as well. Besides these "natural" effects, the energy coming from the sun is used more and more in a technological way, especially in the field of energy supply. For our time scale, the sun is an infinite source of energy, which makes it possible for us to reach an independence from fossil energies and Uranium.