Many explanations have been advanced by scientists to account for the ice ages, or glacial periods So far, all such have failed to explain either warm interglacial periods during the last ice age, or the focalization of continental glaciers such as the Cordilleran, Keewatin, or Labradorean glaciers.
The rapid retreat of glaciers in the Sierra Nevada Mountains, the Cascade Mountains and in the mountain ranges of Alaska during the past fifty years has called attention to a possible cause of glacial periods. For instance, since its discovery in 1880 Muir Glacier, in Alaska, has retreated about thirteen miles Paradise Glacier of Mount Rainier is retreating steadily at about seventy feet per year.
In The Mahatma Letters to A. P Sinnett, on pages 161 and 162, the Master K. H. makes the following statement:
. . . I wonder how Science has not hitherto understood that every atmospheric change and disturbance was due to the combined magnetism of the two great masses between which our atmosphere is compressed I call this meteoric dust a "mass" for it is really one. High above our earth's surface the air is impregnated and space filled with magnetic or meteoric dust, which does not even belong to our solar system. . . . Science makes too much and too little at the same time of "solar energy," and even of the Sun itself, and the Sun has nothing to do whatever with rain and very little with heat. I was under the impression that science was aware that the glacial periods as well as those periods when temperature is "like that of the carboniferous age" are due to the decrease and increase or rather to the expansion of our atmosphere, which expansion is itself due to the same meteoric presence? At any rate, we all know, that the heat that the earth receives by radiation from the Sun is at the utmost one third if not less of the amount received by her directly from the meteors.
In regard to the origin of the glacial and interglacial periods, the following thought seems to present a possible explanation: At present we find our world divided into "life zones," seven in all, three warm, one intermediate, and three cool.
|Boreal or Cool||Artic Alpine||Region of perpetual snow.|
|Hudsonian||Timberline and tundra.|
|Canadian||Zone of spruce and alpine firs.|
|Intermediate||Transition||Zone of the Yellow Pine.|
|Austral or Warm||Upper Sonoran||Chaparral and sagebrush.|
|Lower Sonoran||Hot desert areas.|
|Tropical||Enters U.S. only in Florida.|
Suppose we imagine our earth surrounded by successive layers of these zones, onion-like, but with this difference: that certain zonal layers are thick at the equator, thinning out and finally disappearing as they recede to the north and south. The zonal layer at the equator would be the tropical zone. The next zone would be the Lower Austral (or Lower Sonoran), overlying the Tropical and extending far beyond it both north and south. The next layer, the Upper Austral (or Upper Sonoran), doing likewise. It will be seen that the layers are not uniformly deep in any locality: the dominant zone for that area is greatest in depth and influence. A mountain high enough to rise through these zones would support the forms of life common to each zone.
In general, for each thousand feet we rise in climbing a mountain we find an average decrease of four degrees Fahrenheit in temperature, with corresponding plant and animal life fitted to that environment. In short, we can find Canadian types of life by going to Canada, or by climbing a high mountain.
In the north we find the three higher zones expanding over a considerable range, with the lower zones, wherever present, greatly constricted. In California these same upper zones, when present in our higher mountains, are greatly compressed. Instead of occupying thousands of feet in altitudinal depth, they may occupy a mere few hundred feet. In Alaska, timberline may be near sea level. In Oregon, at about 4,000 feet In Southern California, at something over 11,000 feet.
Taking this passage in The Mahatma Letters as a clue, it seems possible that alternating ice ages and inter-glacial periods may largely be brought about, as the Master's statement suggests, by expansion and contraction of these zones; that cold sections of our zonal scalemay have so expanded in depth as to cause the glaciers already existing there as nuclei to increase greatly in size, finally merging one with the other to form once more an extensive glacial system. On the other hand, it may be that at present we are rapidly leaving the age of ice. Seattle, for instance, may not experience any great change climatically either in temperature or in rainfall, yet the Arctic Alpine-Hudsonian section of the life zone scale in that area may be so raised or reduced in thickness as to decrease the nearby mountain glaciers or even to cause their extinction, and this is likely to occur if the present rate of retreat continues.
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