National Geographic : 1956 Jan
thought: The death of our two friends was not to be useless; we would continue with our work and, in one way or another, sooner or later, find out exactly what the Greenland Icecap was like. In our six seasons of work, much has been learned about this mighty geographical fea ture. We covered approximately 10,000 miles of new trails crisscrossing the icecap south of 74° N., driving our weasels a grand total of more than 60,000 miles. We shot more than 600 seismic soundings, which enabled us to make a map of the bedrock under much of the icecap (map, page 131). Newspapers have reported that we had dis covered that Greenland was not one island, but at least three islands, and possibly an archipelago. We are hardly able to say that. What we found is that the center part of the icecap, as compared with the northern and southern parts, drains its ice into the Disko Bay region through glaciers, the beds of which extend far east under the ice. Some of these glaciers have carved out canyons 20 to 30 miles wide and 300 to 1,200 feet below the level of the sea. For the first time we have an accurate estimate of the amount of ice piled up here, approximately 2.7 million cubic kilometers, as I observed earlier. If this volume of ice were to melt away, the mean level of all the oceans of the world would rise by 24 feet. Furthermore, the land of Greenland and its coastal shelf would rise (because no weight would press it down any more), so that the total increase in ocean depth would be still greater. Ice Lives on Borrowed Cold We found another important thing: One might think that as the climate grew warmer the icecap should have melted away long ago, at least most of it. But it is not so. The rea son is that it has accumulated the cold of the past millenniums and kept it inside, as an icebox would do. The icecap lives today on the cold of past ages. Another important point is that the climatic fluctuations of the past are inscribed, year after year, in the layers of the never. The deeper the layer, the further it goes back into history. Ice brought up from more than 450 feet at the Central Icecap Station by the mechanical borer fell as snow at the time of the American Revolution or earlier. In meteorology we found that an anti cyclone, or high-pressure area, exists in the middle of the icecap but is very thin from top to bottom, a few hundred feet at most. This phenomenon is now known as "the pellicular (skin-thin) anticyclone of the Greenland Ice cap." We found also that there exists a marked inversion of temperatures of the atmosphere in the low layers in contact with the snow surface: the air is up to 10° warmer some 30 feet above the surface (page 143). We left quite a blank spot on Greenland, between 74° N. and 77° N. We expect that this white spot will be wiped out soon. An international expedition, organized by us, is now being planned by the International Commission on Snow and Ice for 1957-59 as part of the world-wide scientific activities of the International Geophysical Year.