| Abstract |
The human use of energy exceeds 14 terawatts and is comparable to the energy dissipations in global scale geophysical processes. This simple fact imposes a fundamental restriction on the available options in the search for alternative energy sources, independently of environmental considerations or technical problems. Only the solar radiative power reaching the Earth clearly dwarfs our energy demand. Heat flow from the Earth, wind, waves, tides, and river flow appear too limited to become main players in the energy game. In this circumstances, and in the light of concerns about global warming, the intrinsic variability of solar power deserves more attention than it receives. The observation of a lunar periodicity in tropospheric temperature, not explained as a tidal effect, provides a calibration of the atmospheric response to radiative forcing, which tends to be obscured by atmospheric feedback mechanisms at other periods. It offers the prospect of a more quantitative measure of the climate effect of solar variability than we have had until now. |
