Geology and Meteorology

Abstract

THE subject of climatic changes has always been of absorbing interest to geologists, and they have been perhaps more puzzled to account for the occurrence of plants of temperate or even subtropical character in Arctic regions than for the occurrence of wide-spread Arctic conditions in temperate regions. To explain these changes in the northern hemisphere, the alterations in the distribution of land and water and consequent influence on the Gulf Stream, the modification of the internal heat of the earth, changes in the position of the earth's axis, variations in the amount of heat given off by the sun, the eccentricity of the earth's orbit, and even fluctuations in the amount of carbon dioxide in the atmosphere, have individually or collectively been invoked. The influence of ocean currents, as xiiodified either by the elevation of a tract of islands to form a continental area or'by the total or partial submergence of a continent, has naturally been regarded as of very great importance. Moreover, the effect which such changes would have on winds has not been neglected, although their local influence has not been fully realized.