Climatic Change

The methods of physical climatology are used to explain climatic variations during the contemporary epoch and in the geological past. Contemporary climatic change is found to depend to a considerable extent on variations in atmospheric transparency. These variations, which change the amount of solar radiation reaching the earth's surface, are associated with the changeable level of volcanic activity. Climatic changes in the geological past are also explained in terms of variations in atmospheric transparency and the changing distribution of the earth's land and sea areas, which influenced circulation in the hydrosphere. On the basis of established regularities in past climatic change, the possible future trend of climatic evolution is suggested. Although the current cooling trend could conceivably lead to renewed expansion of glaciation, this is considered highly unlikely in view of the increasing amount of heat generated by man's growing use of energy. The additional heat may be sufficient in the long run to melt the polar ice and introduce a climate into the middle and high latitudes typical of warm interglacial epochs. Actually, even before this, technology may enable man to eliminate the polar ice artificially. The beneficial and harmful effects of such as step are briefly considered.