The effect of solar radiation variations on the climate of the Earth

It follows from the analysis of observation data that the secular variation of the mean temperature of the Earth can be explained by the variation of short-wave radiation, arriving at the surface of the Earth. In connection with this, the influence of long-term changes of radiation, caused by variations of atmospheric transparency on the ther-mal regime is being studied. Taking into account the influence of changes of planetary albedo of the Earth under the development of glaciations on the thermal regime, it is found that comparatively small variations of atmospheric transparency could be suffi-cient for the development of quaternary glaciations. As paleogeographical research including ma-terials on paleotemperature analyses has shown (Bowen, 1966, et al), the Earths climate has long differed from the present one. During the last two hundred million years the temperature difference between the poles and equator has been comparatively small and there were no zones of cold climate on the Earth. By the end of the Tertiary period the temperature at tem-perate and high latitudes had decreased ap-preciably, and in the Quaternary time subse-quent increase in the thermal contrast between the poles and equator took place, that waa fol-lowed by the development of ice cover on the land and o c e m a t temperate and high latitudes. The size of Quaternary glaciations changed several times, the present epoch correspbnding to the moment of a decrease in the area of gla-ciations that still occupy a considerable part of the Earths surface. To answer the question of in what way the climate will change in future, it is necessary to establish the causes of Quaternary glaciations initiation and to determine the direction of their development. Numerous studies on this problem contain various and often contradic-tory hypotheses on the causes of glaciations. The absence of the generally accepted view-point as regards this seems to be explained by the fact that the existing hypotheses were based mainly on qualitative consideratiow allowing different interpretation. Tellus XXI (1969), 6