Mysteries of glaciation
It surely would be true, if glaciers came from evaporated ocean water, that while the millions of cubic miles of snow or ice were falling to build the prodigious ice sheets, other millions of cubic miles of water must have been falling as rain simultaneously on other portions of Earth’s surface. It seems inconceivable that all the water vapor was carried by air currents only to those certain areas where ice caps were forming and that none of it was carried to other areas where it would fall as rain.
Not one whit more water vapor is being formed now, from day to day, than is condensing and returning to the ocean. Hence it seems impossible to escape the conclusion that evaporation would have had to be more copious when ice caps were accumulating than it is now. How much more copious, depends of course on how long it took the glaciers to mature.
Evaporation Required Per Year
From what we have noted regarding the natural law which controls evaporation, we know that if evaporation were more copious than it is now, climate must necessarily have been warmer—not colder. The question is, how much warmer. If the glaciers were formed say in 20 years, and if they consumed ocean water to a total depth of 1,000 feet, the average consumption per year would have been 50 feet. If it took 20,000 years for the glaciers to form, the average consumption per year would have been a mere one-twentieth of one foot. These figures are exclusive of the amount of water which, as we have reasoned, must have been falling simultaneously as rain on areas where ice was not forming. As the total area of present land known to have been covered by ice was about one-third, and as the present land covers only about one-fourth of Earth’s surface, there was eleven times as much global surface not covered with ice as there was glaciated. So, on a percentage basis, we would be justified in multiplying the estimated annual evaporation figures given above by eleven; but in deference to any claim which might be made that a major portion of the water vapor perhaps was steered in the direction of the glacial areas, let us multiply by eight instead of eleven.
Boiling Oceans
If, then, we choose to assume that the glaciers consumed a total of 1,000 feet of water and were formed in twenty years, 400 feet of ocean depth must have been evaporated per year. To evaporate at an average rate of more than one foot per day, winter and summer, throughout tropical, temperate and frigid zones alike, the oceans would literally have to boil! Can anybody believe that an intensity of solar or terrestrial heat sufficient to make the oceans boil would fail to kill every living thing on Earth? Yet we know that both living creatures and thriving florae very closely akin to present species existed in abundance when the ice arrived.
Furthermore, it is incredible that snow and ice could survive and accumulate in heat sufficient to boil the oceans. Yet the concept demands that one-eighth of all the water evaporated by such intense heat would condense into snow, which, after falling, would survive the heat and accumulate without loss for twenty years! Of course this concept is just too preposterous to be considered.
Slow Growth Assumed
Hence we are forced to resort to the other alternative, namely, that the glaciers formed very slowly, over periods of thousands of years. This is the conception of all theorists; and adherence to the notion is precisely the basic cause of the difficulties in which they find themselves. They know that water vapor from meager evaporation could not remain aloft until the total amount involved in an ice age could accumulate, because frequent rains and snows would prevent it. On the other hand, they just cannot figure out why little annual increments of falling winter snow would refuse to melt in the heat of summers, particularly at low altitudes and in temperate or subtropical zones, but would continue to pile up for thousands of years. In an attempt to escape the horns of the dilemma they conclude that climate just necessarily must have been considerably colder at the time! So they invent the theories which have been listed, in a vain attempt to justify the conclusion. Yet, as we have reasoned, even if refrigeration of climate had occurred, as the theories attempt to prove, the lower temperatures would have lessened, not promoted glaciation.
Some theorists, however, suggest that the snow itself, after sufficient accumulation, even at low altitude and latitude, would set up an “anticyclonic engine” of its own to permit accumulation. Presumably, therefore, after the first hundred years or so of accumulation, there would be no problem. What would prevent melting during the first hundred summers is not stated.
Fantastic Explanations
The assumption that ice sheets accumulated from surviving remnants of ordinary winter snowfalls obviously goes hand in hand with the third assumption, namely, that the glaciers developed slowly. This dual concept has been held since the time of Agassiz and today is still held unanimously by all students of glacial mysteries.
In efforts to overcome the paradoxes inherent in this dual concept, some fantastic and incredible explanations have been suggested. Outstanding among the riddles is the big mystery, already mentioned, of how could small, annual increments of ordinary winter snowfall in temperate and tropical regions possibly manage to survive the heat of following summers for thousands of years while the snow was accumulating and compressing into ice. Ice sheets developed in tropical India, Africa and South America. In central North America, Pleistocene ice fields extended south to the 40th parallel. To explain the latter incident it is suggested that the ice might have formed some 1,500 miles farther north, on highlands assumed to have then existed and “crept” from those “centers” of origin south to the above latitude. If that explanation fails to satisfy, the alternate explanation is: “Well, climate just must have been a lot colder at the time.”