File:The continent we live on (1961) (20497624779).jpg

Title: The continent we live on
Identifier: continentweliveo00sandrich (find matches)
Year: 1961 (1960s)
Authors: Sanderson, Ivan Terence, 1911-1973
Subjects: Physical geography; Natural history
Publisher: New York : Random House
Contributing Library: New College of California
Digitizing Sponsor: Internet Archive

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A herd of musk ox in full flight.These"sheep-oxen" are true relics of the Ice Age and. though they look lumpish, can out- pace most other animals. squeezed out underneath as taffy would be in a shallow bowl if a large solid weight were placed upon it. Thus an icecap grows in both depth and area and pushes out in all directions. If it comes against a substantial mountain range, it pushes up and over the lower passes or flows around the ob- stacle, scouring its sides with millions of tons of pressure and billion-foot-pound scooping actions. It finally covers the whole land and leaves only the peaks of the tallest mountains sticking out. These are called nunataks. Such are strewn all around the edge of Greenland. But finally its edge reaches some seacoast. If the coast is a rocky barrier with cliffs, the ice, in the form of glaciers or rivers of ice, cascades down these through whatever gaps there are and, on reaching the sea below, becomes water-borne— ice being lighter than water. As a result, the front ends or "tongues" of these break off in great bits by being bent upward, often with thunderous noises like gunfire, and then go drifting away as icebergs. This is called calving. If. on the other hand, the coast is low but wide, the ice front may push slowly out onto it, building up a mountainous and bulbous front, actually thicker at that front than just behind it, so that the whole curls over like a vast wave and huge masses of ice crash to the bare ground ahead of it. Then the ice slowly creeps over these chunks and reabsorbs them. In still other cir- cumstances, where the coastal plain is narrow and only just above sea level and extends out under the water to form a very shallow sea, the vast ice mass may move slowly out from the land—sometimes for hundreds of miles as in the Antarctic— before its buoyancy counteracts its weight and vast slices of it snap off and become water-borne. This is known as shelf ice; and it is prevalent around enormous stretches of the Antarctic coast but it is not found in the Arctic. When this shelf ice— sometimes hundreds of feet thick—breaks away, it forms flat- topped icebergs that have been recorded up to two hundred miles long and a hundred miles wide. Sooner or later, however, the climate changes once more and the icecap begins to suffer starvation. Perhaps nothing more than a diminution in annual precipitation takes place, so that no new snow piles up on the center or it does so in such small quantities that it cannot keep up with the summer thaw. Then the move- ment of the ice ceases; its peripheral glaciers melt backward up their gorges; on low land, its bulbous front flattens out into a thin, tapering sheet and develops melt caves beneath it; and the great ice shelves begin to slant downward to the sea and then slowly retreat back onto the land. Such is Greenland today— though perhaps only temporarily—a really vast and fairly an- cient icecap just a little past its prime, shrinking visibly almost all around and with considerably reduced edges on land but still calving icebergs along both its northwestern and eastern coasts. An icy blanket of air still pours off its edges in most places force- fully enough to be termed idiabatic winds, but it is not nearly so formidable or aggressive as it was even a century ago. Things have been warming up generally in those parts for some time now, so that all manner of animals once found only in temperate seas now occur there. Codfish, which only fifty years ago were never caught north of 64 degrees north, now form com- mercial catches north of 73 degrees north. This is a tremendous movement for fish, which are ultrasensitive to water tempera- tures, being nearly six hundred miles of latitude. All kinds of other changes have been taking place, too. The sea ice has
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become thinner and narrower, and it melts sooner and stays away for longer periods than it did previously. This has upset the inshore habits of such marine mammals as whales and seals. The graves of the Norse settlers of pre-Columbian times have thawed out of the permafrost; quite a number of new plants have appeared on the coastal fringe in summer; and birds not seen before are now common in many areas. These are not unalloyed blessings: rather the contrary, for they have removed far to the north many of the natural products, such as whales and seals, on which the Greenlanders relied for food and cloth- ing. Much the same is happening on the Canadian islands, but the change there is not so apparent and is possibly not so pro- found. In Greenland it seems to be caused primarily by changes in the warmer ocean currents and the wilting of the icecap, and it is believed that it is not an increase of warm water but of cold that is causing the latter, for as the warm water goes farther away it carries the moisture-laden air that brings precipitation. GARDENS BY THE ICE The coastal strips of Greenland are very unlike what most of us suppose. Even in midwinter the climate is not really any colder than that of the northern United States, and in summer it can be very (though never disagreeably) hot, so that people go swim- ming in lakes and wander about in shorts even as far north as upper Baffin Bay. There are places within the Arctic Circle that 20

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