The Arctic Home in the Vedas c5.17

c5.17

If Dr. Croll had gone only so far, his position would have been unassailable, for the cause, enumerated above, is sufficiently potent to produce the climatic changes attributed to it. At any rate, if this was not the sole cause of a succession of Glacial and Inter-Glacial periods, there could be no doubt that it must have been an important contributory cause in bringing about these changes. But taking the value of the eccentricity of the earth's orbit from the tables of Leverrier, Dr. Croll calculated that during the last three million years there were three periods of maximum eccentricity; the first of 170,000, the second of 260,000, and the third of 160,000 years; and that 80,000 years have elapsed since the close of the third or the last period. According to Dr. Croll the Glacial epoch in the Pleistocene period must, therefore, have begun 240,000 years ago, and ended, followed by the Post-Glacial period, about 80,000 years ago. During this long period of 160,000 years, there must have been several alternations of mild and severe climates, according as the winter in a hemisphere occurred when the earth was at perihelion or aphelion in its orbit, which happened every 10,500 years during the period. But as the cold epoch can be at its maximum only during the early part of each period, according to Dr. Croll's theory, the last epoch of maximum glaciation must be placed 200,000 years ago, or about 40,000 years after the commencement of the last period of maximum eccentricity.