Published online by Cambridge University Press: 24 August 2009
The major anthropogenic sources of heat pollution in 1989 have been identified, and the ultimate heat generated has been calculated. Those sources include the combustion of fossil fuels and of biomass, nuclear fission, and the burning of forests. The total rate of heat generated from such sources for the world as a whole, 16 to 26 TW, is compared with a very approximate estimate of the heat retained at the Earth's surface, 291 TW, resulting from decreased radiative heat-loss due to increased concentration of atmospheric CO2. However, heat pollution may be more important than the ratio of about 5 to 9% would appear to indicate. It is a direct process producing heat at the surface of the globe, not subject to moderating feedback mechanisms, and is expected to be most pronounced at land-based sites marking centres of high industrial and other human developments. On the other hand, global warming due to increased atmospheric CO2 is an indirect process that is dependent on many factors, not all of which are known or measured — such as the extensive smoke-clouds resulting from the forest fires in Amazonia. Compared with preindustrial times, the rate of heat pollution has grown by a factor of more than forty.