Solar Variability and Planetary Climates

2 With a global average irradiance of 342 W/m , the Sun is by far the largest source of energy for planet Earth. In comparison, the internal energy produced by Earth 2 itself is only about 0. 087 W/m (Pollack et al. , 1993), which in turn is 3. 5 times 2 larger than the 0. 025 W/m of heat produced by the burning of fossil fuels. About 31% (31 units) of the solar energy which arrives at the top of the - mosphere is reffected back to space by scattering from clouds, aerosols, and the Earth’s ...