The average amount of the sun’s radiation that penetrates the atmosphere and reaches the earth is 51% of the total incoming energy as illustrated. Of the 49% that does not reach the earth, 30% is reflected back into space and 19% is absorbed by the atmosphere and clouds. The total solar energy absorbed by Earth’s atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year.
The earth’s energy use by mankind is approximately 500 exajoules per year. This is about 0.01% of the total yearly energy coming from the sun. Putting this in another way, the earth absorbs more energy in one hour than the world uses in one year according to physicist Steven Chu, US Energy Secretary and former Director of Lawrence Berkeley National Laboratory. In total, the sun emits about 2.2 billion times the amount of radiation that is received by the earth.