Introduction

Abstract

The Earth receives energy from the Sun at the rate of about 170 million gigawatts, a figure that is hard to imagine but which is equivalent to about 40 megawatts for every living man, woman and child. Ultimately, all this energy is reradiated back into space, but the finely tuned interactive processes involved within the Earth’s atmosphere and energy-absorbing systems determine the average environment temperature in which life may flourish. Initially 30 per cent is reflected directly, 47 per cent is absorbed by the Earth’s atmosphere and 23 per cent is absorbed in evaporating the seas to provide rainfall. Only 0.004 per cent is absorbed by plants to produce ‘biomass’ material. Of this, only 3.5 per cent is used as food by man and his domestic animals. The remainder is potentially available as a feedstock for chemical manufacture and for fuel. Solar energy absorbed in the photosynthetic process is later released in oxidation reactions (either by fire or in the bodies of living organisms) or by bacterial decay, to be absorbed by the atmosphere and subsequently reradiated back into space.