Climate models and variations in the solar constant.

Abstract

A summary is given of results obtained by a number of authors using simple zonally-and annually-averaged climatic models. It is shown that most of these results can be explained quite easily using a globally-averaged model. It is also shown that, depending on the parameterization used, the percentage change of the solar constant, relative to the present value, required in the model, (a) to initiate an ice age is -2 to -5 percent, (b) to produce and ice-covered earth is -6 to ·14 percent, and (c) to start the melting process on an ice-covered earth is -8 to + 33 percent. Thus the margin of possible error increases significantly as one moves away from present conditions.