ABSTRACT
Virtually, all of the energy at the surface of the Earth, and in the atmosphere, comes to us from the Sun. (By contrast, the heat f lux from the Earth’s interior, a legacy of the radioactive isotopes that were present at the planet’s birth, and cooling of the interior from its formation, is smaller by a factor of around 5000.) This is the energy which maintains our current surface temperature, although the greenhouse effect is essential to maintain that temperature in the range where liquid water is present. As we saw in Chapter 6, this is also the source of all the energy contained in atmospheric and oceanic motions (with the exception of tidal motion). Thus, wind and wave energy, as well as solar thermal and photovoltaic energy, are all forms of solar energy.
