The Coming Ice Age

CHAPTER I.. Page

PAGE

CAUSE OF COLD AND MILD PERIODS, 9–36

Traces of ancient glaciers in temperate zones, 9; prevailing winds the main cause of the circulation of the ocean waters between the tropical and temperate zones, 10; general direction of prevailing winds, and how, in connection with continents, they circulate the surface waters of the sea, 11; high and low sea-levels; separation of antarctic lands from South America, 12; Captain Larsen’s discoveries in antarctic regions, 13; how low lands south of Cape Horn were submerged, 13; how the winds move more surface water southward than northward, 14; Dr. Croll’s views on winds and ocean currents, 16; under-currents of the ocean, and how caused, 16; Gulf Stream currents, 17; antarctic under-currents, 18; why the winds were able to force more of the ocean waters southward than northward at the close of the Tertiary age, 19; Mr. Alfred R. Wallace’s views on Tertiary seas, 20; how the Cape Horn channel affects the ocean currents, 21; cause of the increase of cold in southern latitudes, 22; how the Cape Horn channel is closed during ice age, and its effect on ocean currents and temperature of southern latitudes, 24; the melting of glaciers from southern lands, 27; a salt sea requisite for circulation during ice age, 28; direction of surface currents in southern seas, 29; Humboldt current, 30; Agulhas current, 32; temperature of arctic ice, 34; movement of southern icebergs, 35; glaciers south of Cape Horn, 36.

CHAPTER II.. How Ice Periods in the Northern Hemisphere Are Brought

HOW ICE PERIODS IN THE NORTHERN HEMISPHERE ARE BROUGHT ABOUT, 37–54

Northern seas during Tertiary age, 37; Gulf Stream during Tertiary times, 38; the origin of a cold period in the northern hemisphere, 38; remarks on Gulf Stream and arctic currents, 39; circulation of arctic waters, 40; arctic channels during ice age, 41; how the weight of glaciers in the northern hemisphere attracts the waters of the southern seas during ice age, 42; Professor Prestwich on the submergence of European lands, 43; the great Atlantic tide rips the head-waters of the Gulf Stream, 44; high sea-level of Atlantic calm region, 45; tropical Atlantic currents, 46; Sargasso Sea, 48; arctic and Gulf Stream currents, 49; Pacific Ocean currents, 50; slow growth of an ice period, 52; reduction of Cape Horn channel, 53; permanence of antarctic glaciers elevated above the snow-line during mild periods, 54.

CHAPTER III.

SPREAD OF GLACIERS DURING COLD EPOCHS, 54–61

Spread of glaciers in tropical zone, 54; Professor Agassiz on the origin of Galapagos Islands, 55; the bowlders of Hood’s Island and rookery of Albatross, 56; alpine flora of Galapagos and tropical America, 57; Mr. J. Crawford on ancient glaciers in Nicaragua, 58; Cuba and Republic of Colombia during ice age, 58; destruction of animal life during glacial age, 59; temperature of North Atlantic and Mediterranean Sea during ice age, 60; temperature of ocean during warm epochs, 61; generative age ascribed to warm eras; Professor Wright on pre-glacial man, 61.

CHAPTER IV.

THE GLACIERS OF THE TEMPERATE ZONE, 62–75

Professor Hitchcock on the early history of North America, 62; glacial deposits of Nantucket and Martha’s Vineyard, 63; Professor James Geikie on the glacial deposits of Northern Italy, 64; California coast ranges the work of Sierra glaciers, 65; ancient glaciers on the Pacific slope north of California, 67; Professor Geikie’s views on the ancient glaciers in the Salt Lake region, 68; Colorado Cañon, 69; the conglomerate deposits in the Appalachian district, 69; remarks on the glacial boundaries in United States during ice age, 70; sands of Florida, 71; ancient ice-sheets of the plains west of the Mississippi River, 73; the driftless region of Wisconsin, 74; tropical waters of North Atlantic chilled during ice age, 75; the drifted snow of British America and Siberia during ice age, 75.

CHAPTER V.

REMARKS ON THEORIES ADVANCED FOR EXPLAINING ICE PERIODS, 76–93

Professor Geikie on supposed causes of the glacial period, 76; change in the relative level of the land and sea during glacial and post-glacial times, 77; submergence of northern lands at close of ice age, 78; the main cause of the movement of water from the northern seas at the close of glacial age, 79; why the earth-movement hypothesis should be rejected, 79; glaciers of Europe and Alaska, 80; North Pacific currents, 81; why the Pacific waters are growing cool, 82; the lowering temperature of the northern seas, 83; the increase of cold in Europe and Asia, 84; falling temperature of the Andean region, 85; General Drayson’s astronomical discoveries for explaining the cause of ice periods, 87; why the Gulf Stream was always confined to the North Atlantic, 89; the improbability of the Indian Ocean currents entering the arctic seas, 90; why the increase of glaciers must continue while the Cape Horn channel maintains its present capacity, 91; comments on the coming ice age, 92; tropical zone the abode of man during ice age, 93; preservation of the tropical ocean fauna through the glacial period, 93.

CHAPTER I.. Cause of Cold and Mild Periods.

CAUSE OF COLD AND MILD PERIODS.

It is now generally conceded by those who have given the subject much attention that the greater portion of North America above the latitude of 39° north to the shores of the Arctic Ocean has been furrowed and scoured by the action of ice.

Vast traces of ancient glaciers are also found in Europe; for it is reported that ice-sheets have left unmistakable marks of having overrun the greater part of the lands lying between the arctic seas and the latitude of the Pyrenees.

In Asia evidences of glacial action have been noticed from Northern Siberia to the mountains of Syria.

The great glaciers of Himalaya have in times past attained gigantic proportions. In Northern China huge bowlders are found scattered over the valleys, and a long distance from the mountains.

The southern hemisphere, in proportion to the extent of its land surface, shows ample traces of former ice action. From the latitude of 38° south to the southern extremity of the western continent there is said to be the clearest evidence of former glacial action in numerous bowlders scattered over the land.

On the shores of the South Pacific, from the Island of Chiloe to Cape Horn, the coast is fringed with deep fiords, which appear to be channelled out by ice, like the fiords of Norway and Greenland. And at this date the mountains of that southern region are covered with snow, and the glaciers which flow down the valleys are said to reach the tide-water as far north as the latitude of 47° south. The glaciers of New Zealand, now of Alpine proportions, during the ice age descended to the sea, and channelled the deep fiords on its south-western coast; and certain traces of glacial action have been observed in Southern Australia, and also in the province of Natal, South Africa.

Kerguelen Land is pierced with deep, narrow fiords, which have the appearance of having been the work of ancient glaciers.

The lands south of the antarctic circle are to-day supposed to be covered by an ice-sheet, of which the great ice barrier surrounding that region furnishes ample proof.

While impressed with the above reports of the work of ancient glaciers, in connection with my own observations along the shores of the several oceans, I have been led to seek for the physical causes which brought about the great climatic changes of past geological ages. And, while having the subject under consideration, I have had my attention directed to the manner in which the great prevailing winds in connection with continental lands are able to move the heated surface waters of the tropical oceans into the colder zones, and also transfer the cold waters of the higher latitudes into the tropical zones.

And it is through this grand movement of the ocean waters that we are enabled to account for the difference in the temperature of places now lying in the same parallels of latitude.

The natural methods for conveying tropical heat into the higher latitudes, and also for excluding it therefrom, are so simple and efficient that on due consideration we are able to conceive how epochs possessing mild climates have been succeeded by periods of frigidity.

It has been admitted by several writers on climatic changes that, should the tropical surface waters of the ocean be moved into the high latitudes in large volume, thus adding their warmth to the heat imparted by the sun, such combined heat would cause a mild climate. And it has been estimated that the amount of equatorial heat moved into the temperate and polar regions of the northern hemisphere by the Gulf Stream alone is equal to one-fourth of all the heat received from the sun by the North Atlantic from the tropic of Cancer to the arctic circle. Still, it appears to me, while viewing the subject from a marine standpoint, that the explainers of climatic changes have never fully comprehended the manner in which the surface waters of the ocean are moved from the tropics into the high latitudes, and returned from the high latitudes to the tropics. Consequently, they have neglected necessary and efficient natural agents in their explanatory theories, and with much learning and ingenuity have laboriously sought to show how great changes of climate could be brought about through other causes.

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