ABSTRACT
Climatic change is recognized to have had a significant influence on the evolution and geographical distribution of the earth’s species and it may similarly have affected the history of civilizations. However, the amplitude of climatic changes, the manner in which they occur – abruptly or gradually – and their causes are controversial matters. One of the observations to come out of W. D. Sellers’s model is the extreme sensitivity of high latitudes of the northern hemisphere to factors which would produce climatic change. A decrease in the solar constant of 0.6 per cent in the model results in a temperature drop at 65°N of 3.5°C in February and 4.1°C in August. The palaeoclimatic record is beginning to provide guidelines as to the climatic changes likely to result from changes in either the total energy input to the earth–atmosphere or in its latitudinal distribution.
