Article — From the September 1958 issue

The Coming Ice Age

A true scientific detective story

( 3 of 8 )

A JACKPOT IN ICE

NEITHER Ewing nor Donn can say precisely when the hunch came. The problem continued to tantalize them, as they traveled about the country attending meetings and doing field work. On the way back from Chicago, they may have watched the ice break up in the Delaware River. They recall reading a newspaper item about a big gambling jackpot on which day the ice would go out in the Yukon. The chain of thought seems obvious now: water freezing — ice going out — this is a sharp, abrupt change, the only sudden change that can happen to a body of water.

But oceans don’t freeze. Ocean currents dissipate the cold — except, of course, in the small Arctic Ocean which is almost entirely surrounded by land.

“What would happen if the ice went out of the Arctic Ocean as it does in the Yukon or the Delaware?” Ewing and Donn remember wondering, as they went over the problem again, one day at Lamont.

“Well, we figured, the Arctic Ocean would get warmer. Because water would flow more freely between it and the Atlantic, dissipating the cold. And of course, the Atlantic Ocean would get colder. But wait a minute . . . we saw it simultaneously. If the Arctic Ocean were open water, warmed by the Atlantic, warmer than the land around it, water would evaporate and fall as snow on the land. More snow on Greenland and northern Canada would make glaciers grow. Glaciers don’t grow now because there is no open water in the Arctic to provide the moisture for snow.

“And suddenly we had the startling hunch that the Arctic Ocean was open during the Ice Age. And that it froze over only 11,000 years ago. It was this freezing over of the Arctic Ocean which so suddenly warmed the Atlantic — and ended the Ice Age.”

“That rather exciting ten minutes,” they told me, “contradicted a whole lot of things we’d always taken for granted. Everyone has assumed that the Arctic Ocean, so covered with ice today, would be even colder and more completely frozen during an Ice Age.

“You get a lot of these wild ideas in our business. If one lasts five minutes you begin to take it seriously. The more we thought about this one, the more it added up. It explained so many things that have always puzzled us.

“For once you accept the radical idea that the Arctic was a warm open ocean at the time of the great continental glaciers, you can reconstruct a completely different weather pattern from the one we know today. As we worked it out, we could see a startling chain of cause and effect between the oceans and the glaciers themselves. We could see how the oceans would work as an actual ‘thermostat’ to keep the earth alternating between glacial ice ages and interglacial periods such as today.

“It all hinges on the fact that the North Pole is where it is — in the middle of the Arctic Ocean, which is almost completely surrounded by land except for a shallow ‘sill’ between Norway and Greenland opening into the Atlantic, and the insignificant Bering Strait. If the cold waters of the Arctic interchanged freely over this sill with the warm Atlantic water, the Arctic Ocean would not freeze over. Its moisture would build glaciers. (In the cold temperatures of the north, the moisture that evaporates from the open Arctic would all fall as snow — too much snow to melt in the short Arctic summer. When the rate at which snow accumulates exceeds the rate at which it melts, glaciers grow.) But as those glaciers grew, they would lock up so much ocean water that sea level would fall.

“We know that sea level was lowered between 300 and 400 feet at the peak of the last Ice Age. Now, most of that sill between Norway and Greenland is less than 300 feet deep. At a certain point the glaciers would lower the sea level so much that the Arctic Ocean would be virtually cut off from the warmer Atlantic. The Arctic Ocean would then freeze over. And the glaciers, no longer led by snow, would melt under the Arctic summer sun, restoring their water to the oceans. Then sea level would rise, until enough warm Atlantic water again flowed over that sill to melt the Arctic ice sheet, and start another glacial cycle.”

Donn worked out a weather map of the world, with an open Arctic Ocean, warmer than surrounding lands. It showed a completely different storm pattern than exists today; more rain and snow in the Arctic, a wind pattern carrying more ocean moisture inland generally. It showed violent blizzards over eastern North America which would spread more snow on the glaciers. Summers would become more like winters as the glacial wall advanced southward. Donn’s weather map with the open Arctic even showed that there would be rain in today’s deserts.

But they needed more proof for their theory. They had to track down the circumstantial evidence of what happened 11,000 years ago; they had to find geological witnesses to confirm their reconstruction of the crime.

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