Discovering the window to the past

Alfred Lohar Wegener, the German meteorologist who launched a revolution in the earth sciences, observed his fiftieth birthday in a small cave excavated from the accumulation of old snow high up on the inland ice of Greenland. He celebrated with an apple and some sweets. More important to him that day were the desperate circumstances facing the five men in the cave and the critical turning point of their scientific expedition. Outside the cave, a powerful, dangerously cold wind was blowing across the glacier. The long Arctic winter was closing in. The weather had been terrible for a month. Some 250 miles from their base camp, five men were crowded into a freezing vault provisioned for the winter with barely enough food for three. Nearly 10,000 feet up on the ice cap, the "Mid-Ice Camp"—Eismitte, in German—was without a radio transmitter, completely cut off from the outside world.

It was November 1, 1930, long before Wegener would be recognized as one of the great visionaries of science. A thoughtful and quietly attractive personality, Wegener inspired deep affection and respect from students and colleagues and most especially from the 20 countrymen who had followed him to Greenland that spring. At the same time, among many who knew him not at all, he was the object of a kind of loathing that only rarely is seen in science. In those days, more than a few geologists in Europe and the United States would have been perfectly happy to hear that this meddlesome fellow with his cockeyed theory about drifting continents was safely packed away in the frozen reaches of one of the most remote places on Earth.

Important as the occasion was to the history of geology, the events in Greenland are enriched all the more by what they would come to mean to the progress of climate science that just now is unfolding. Another important idea was about to be born. The sturdy and brave men of the Wegener Expedition, as it came to be called, were about to open the first window onto the finely detailed landscape of climates past that eventually would be illuminated by the Greenland ice. One of the men in the cave was about to dig down and look closely at the layers in the snow—to unlatch that window and peer out. Wegener would not live to witness this accomplishment, just as he would not live to see his profound insight into the terrestrial history of Earth so completely win over the science of geology 30 years later.

Since he first published his theory in Germany in 1912, Wegener's vision of a planet composed of continents drifting like icebergs on a sea of heavier crust had been nothing but trouble. His own father-in-law, the climatologist Wladimir Koppen, had urged him to give it up. The president of the American Philosophical Society had dismissed the idea as "utter, damned rot," and debate among geologists had been going on for a long time.

The continents seem to fit together like pieces of a jigsaw puzzle, Wegener argued. Similarities among fossilized plants and animals and geologic formations on land masses separated by oceans suggested a time when the lands of Earth were composed of a single large continent. The big question was how: What forces could cause such a supercontinent to fracture and its pieces to drift apart over the eons? The explanation of the mechanisms of plate tectonics and the turning over of the planet's viscous interior would evolutionize the earth sciences in the 1960s. However, neither Wegener nor anyone else had a satisfactory explanation at the time.

Established theory held fast. Men had spent years developing a theory of the molten history of Earth, proposing that the mountains, valleys, and oceans were formed during a long period of planetary cooling. In the process, Earth took on the look of a shriveling fruit, its skin cracking and folding as it shrank. To the leaders of geology, the configuration of the continents was immutable.

In the early days of the century, when the lines between the disciplines were more freshly drawn, many authorities took great personal offense that this outsider to their sciences would presume to contradict the received theories.

As a young man, Wegener had visualized the idea of continental drift as a singular truth and thereafter devoted much of his persuasive skills to marshaling the various sciences to the cause of establishing its substance. He challenged botanists, biologists, and geologists to abandon cherished beliefs and to think across the disciplinary lines they had worked hard to protect. This comprehensive approach eventually would be seen as vital to understanding the workings of Earth, especially its climate, but not in Wegener's day. The farther the young German ranged in pursuit of his theory, the more professional and personal antagonism he seemed to provoke.

It wasn't long before the established authorities closed ranks against Wegener's concept as if they were stamping out a plague. He never understood the depth of resistance to his thinking. Continental drift was received not merely as a mistaken idea but as an evil that jeopardized the credibility of geology as a science and the professional reputation of anyone who espoused it. Wegener was denied professorships at German universities, but eventually he found himself at the University of Graz in Austria. Ironically, though, in 1928, he was asked to lead a German expedition to Greenland.

The geophysicist Emil Wieckert at Gottingen University had developed the "seismic" method of measuring Earth's interior, setting off "artificial earthquakes" by means of explosions and measuring their waves. Wilhelm Meinardus, an influential Gottingen geographer and himself an Arctic specialist, proposed that Wegener lead an expedition that would field-test Wieckert's new method on the mysteries of the Greenland ice sheet.

At age 50, Wegener was highly regarded as a meteorologist. A popular lecturer, he was the author of an important and successful textbook, The Thermodynamics of the Atmosphere, which contained valuable insights into the formation of rain. Also, Alfred Wegener knew Greenland better than just about anybody in Europe. At the age of 26 he had served as meteorologist for a Danish expedition there in 1906-1908, becoming the first scientist to use kites and tethered balloons to study polar air circulation. During a second expedition in 1912, Wegener and a Danish companion became the first Europeans to spend the winter in the inland ice, and they trekked more than 600 miles across the great ice sheet.

During World War I and the following years of economic hardship, when scientific funding in Germany was scarce, Wegener could only dream of returning to Greenland. But in 1928 he persuaded the German sponsors to expand the expedition's scientific mission to include questions of meteorology, such as storm tracks and the climate of the ice cap, that had been raised during his earlier explorations of the ice sheet.

By November 1, 1930, as the five men in the ice cave sat down to what one described as a "war council," their ambitious scientific mission seemed very much in jeopardy. The mid-ice camp was the center of a three-station cross section of the ice cap that would make meteorological observations from coast to coast along the latitude of 71° North. This is where the critical questions about the depth of the inland ice, its climate, and its effects on regional weather would be investigated most effectively.

The transect of observing stations would test the theory put forward by William H. Hobbs, a prominent University of Michigan geologist, that the large ice sheets of Greenland and Antarctica create their own climates that are dominated by a "perpetual anticyclone" of high pressure and offshore winds. Among those most interested in the Hobbs theory and its promise of clear skies were executives and pilots of the fledgling commercial airline industry who were looking for the best routes across the North Atlantic. The meteorology for both regions turned out to be more complex than was thought at the time, although the subject would be a matter of debate for years as theorists tried to reconcile contrary field observations. In the case of Greenland, in fact, the frequent circumstances of low pressure, and of summer and winter snowstorms, would make the ice sheet a high-fidelity archive of climates past.

Anticipating the clear skies associated with high pressure, the Wegener Expedition was surprised by the frequency and the incredible severity of storms over the ice sheet. As one member of the expedition would report, "On the whole the weather in the central station was far worse than we had expected. Frequently we were under the influence of depressions with snowstorms and overcast skies."

So severe was the weather that the expedition was unable to transport adequate provisions and equipment 250 miles over the high glacier from the western station to make the mid-ice camp ready for winter habitation. Two motor-driven sleds powered by aircraft propellers had proven unreliable over the uneven surface of the ice. For the traditional dogsleds, the weather had been terribly hostile—storm after storm of soft, deep snow and day after day of powerful, bitterly cold wind. Already, by late October, temperatures had fallen as low as -65°F. Several supply missions had turned back, leaving the mid-ice camp without such basic items as a hut to live in and an adequate fuel supply. Wegener had arrived just two days earlier on a last, desperate dogsled journey from base camp. For 40 days, he, fellow meteorologist Fritz Loewe, and the young Greenlander guide Rasmus Villumsen had slogged through terrible storms and cold. Most of their crew had turned back. What kept Wegener going was his fear for the lives of the two men he had stationed up on the inland ice and his concern that the expedition's scientific goals were about to be lost. Pushing on, they were forced to abandon the petroleum and scientific equipment intended for the camp. About all Wegener had accomplished bringing to the outpost was another mouth to feed: Loewe's feet were so seriously frostbitten he would be unable to make the return journey.

If the science mission were to be salvaged, the expedition leader knew he had to rely on the courage and fortitude of two men—Johannes Georgi, 41, a meteorologist from the Naval Observatory in Hamburg, who would make balloon-borne and other weather observations, and Ernst Sorge, 31, a secondary school geography teacher from Berlin, who would be responsible for measuring the depth and structure of the glacier.

At the war council, Wegener was happy and fresh, acting as if he had just come in from an invigorating walk. As Sorge would recall, "He was fired with enthusiasm and ready to tackle anything." If Sorge and Georgi were intent on abandoning the winter station, Wegener said he was prepared to stay there himself through the winter with Loewe. But the two men calculated that they had just enough food and fuel to keep three men alive for six months. In place of a simple hut, they had made a home in the ice. Sorge and Georgi assured their leader that they were comfortable in the ice cave and ready to carry on the scientific work. "Whatever may happen, the cause must not suffer," Wegener had written earlier to Georgi. "It is the sacred thing which binds us together. It must be held aloft under all circumstances, however great the sacrifices may be. That is, if you like to call it so, my expeditionary religion. It guarantees above all expeditions without regrets!" Wegener and the Greenlander set off early on the morning of November 1 to return to the base camp.

For the men who spent the winter of 1930-1931 atop the ice cap of Greenland, mere survival might have been achievement enough. Certainly it was for Fritz Loewe, who would endure incredible pain and suffering through the long winter. Yet Sorge and Georgi, fired with Wegener's expeditionary religion, did more. The Wegener Expedition would be famous among European weather and ice specialists of the age for the remarkable science it accomplished.

The highest tribute would come from another hero, the explorer Augustine Courtauld, who was a member of the British Arctic Air-Route Expedition, which, coincidentally, also lost its charismatic leader, Gino Watkins, that same year in Greenland. Courtauld had spent five months alone the same winter in a better-equipped ice cap camp 440 kilometers northeast of Eismitte. Snowdrifts had buried him alive, trapping Courtauld in his tent for days before Watkins arrived to dig him out. "Few people can realize what difficulties these men had to work under," Courtauld told a meeting of the Royal Geographical Society in London, on a December afternoon in 1932 when Sorge presented his findings. "They had neither house nor tent, very little fuel, and a bare sufficiency of food; yet they were not content with eking out their existence, but, as we have seen, they made every conceivable sort of observation under conditions which one would have thought would have entirely prohibited any sort of scientific work."

Sorge would write, "The snow-line was the line of demarcation between our labours. Everything above that was investigated by Georgi, everything below it belonged to my sphere." While Georgi braved the cold and wind to maintain a routine of meteorological observations, Sorge dug down into the ice, excavating a shaft like a hard-rock miner in a deep freeze. This first scientific effort to explore the interior of the Greenland ice was an especially dark, cold, lonely, and dangerous occupation in the winter of 1930. Sorge had to work alone. Georgi was busy with his own observations, and through the winter Loewe was too weak and wounded to get out of his sleeping bag. All Sorge had to work with was a saw, an ax, and a shovel. His only light came from a small kerosene lamp he made himself. He had no rope to haul the heavy chunks of ice out of the shaft or to fashion a ladder to drop down into it. Improvising, he dug a stair-stepped shaft that extended 35 feet below the ice cave, followed by a vertical shaft that dropped down another 15 feet, carrying out the big icy chunks by hand. One misstep on the dark stairway of ice could mean serious injury. At any time, he could be killed by a cave-in.

Work in the shaft occupied every afternoon. At an elevation of 9,850 feet, every exertion came at a high physical cost. On an average day, Sorge would haul out 300 pounds of ice before retiring to his sleeping bag, exhausted and cold. Using a ski pole and the brass leg of some instrument that had not arrived complete, he bore holes into the ice to monitor temperatures at various depths. Plugging the boreholes with sackcloth and old tin cans, and checking the thermometers every other afternoon, he was able to observe how deeply the warming effect of the previous summer had penetrated the ice. Diminishing with depth, of course, the warming advanced about a yard a month, he estimated, but no seasonal variations ever reached the deepest borehole 54 feet below the surface, where the temperature was always -19.57° F.

Working in the relative comfort of the cave's main room, Sorge would use the saw to carefully shape squared blocks of icy, granular old snow, orfirn, and then measure their dimensions and weigh them. "In this way I was able to get a complete series of figures for the density of the firn at various depths," he wrote. "The density of course increased with depth." This pattern to the density intrigued him. Sorge was able to see layers in the icy snow, but they were not the kind of layers he was used to seeing in the glaciers of the Alps, where the warming sun of summer causes a dense formation of ice crust. On the ice cap of Greenland at 71° North, even summer temperatures were too cold to allow melting of the surface snow. In fact, Sorge told the geographers in London, "it is impossible to see the stratification caused by the change of summer and winter, as we can in the alpine glaciers." From 120 measurements taken during the winter, however, he was able to report that "the change of summer and winter layers was ascertained by changing densities. On the whole the density increases, but with small oscillations, so that each winter layer is a little denser than the adjoining summer layers. That is the reverse of the conditions in the Alps."

What most impressed fellow scientists at the time were Sorge's seismic measurements of the thickness of the inland ice. By setting off explosions at the surface, Sorge was able to register the waves reflecting off the bottom of the ice cap using his seismograph. By precisely timing the arrival of the waves, Sorge estimated that the ice sheet under the mid-ice camp was 6,500 feet thick, perhaps even as much as 8,775 feet. Could the Greenland ice sheet possibly be two miles deep? Presenting his results in London in 1932, Sorge heard the British geographer Frank Debenham call the thickness of the Greenland ice cap a "tremendous surprise" to glacier specialists. Debenham called it "the most momentous piece of work of a scientific kind connected with ice that has happened for a very long time. If, for instance, the height of the Ice Cap in the centre of Greenland is nearly 10,000 feet, while the height of the land underneath is only 1,000 feet above sea-level, it will at once lead to a large number of other questions with regard to the elasticity of the Earth's crust; as to what may have happened in the Pleistocene Ice Age, for instance, when we had presumably the same kind of ice-cap in Great Britain; in fact, there is no end to the echoes of these explosions of Dr. Sorge's."

Augustine Courtauld described the results as "entirely new to exploration" and found it "fantastic to hear that the depth of 9,000 feet of ice can be sounded by the echo from a trivial explosion of a few pounds of dynamite on the surface."

It would be some years before researchers would fully appreciate the value of Ernst Sorge's cold and lonely work in the winter of 1930 when he sawed and chipped and shoveled a shaft 54 feet down into the Greenland ice. Glaciologists at the time thought of the ice sheets almost exclusively as geological features whose movement across the landscape chronicled the slow waltz of a changing climate. Sorge's work led the way to the recognition of the ice itself as a remarkably faithful archive of atmospheric history. Among the first to recognize and describe the ice as a record of ancient atmospheres was the Swiss glaciologist Henri Bader, who saw polar ice as "a treasure trove" for scientists and in the 1950s first promoted the idea of drilling ice cores into polar glaciers. Under such ice sheets, he said, "every snowfall, including everything that fell with it, is, so to say, separately and safely filed for future reference." He described Sorge as "the first man literally to dig into the files."

At a symposium marking the beginning of the International Geophysical Year in 1957, Bader credited Sorge with what he called "the most fruitful law of polar glaciology" At any given location in the dry-snow region of a glacier, according to Sorge's law, the density of the snow in relation to its depth does not change with time unless the climate changes. Analyzing Sorge's data, Bader developed a mathematical expression that came to be known as "Sorge's Law of Densification." With this law as their guide, later investigators, such as the American Chester C. Langway, could determine the amount of annual accumulation even though they could not detect annual layers in their ice cores.

For all the science it accomplished, the 1930 Wegener Expedition would be most remembered for the singular fact that after Alfred Wegener departed Eismitte on the morning of November 1, 1930, to return to the base camp, he was never again seen alive. All through the long months of winter, nobody knew his fate. The scientists at Eismitte had no way of communicating to the base camp that Wegener had departed the mid-ice camp. Sorge, Georgi, and Loewe hoped and prayed that Wegener and Villumsen had successfully returned to the western coast. Under the circumstances, the scientists at base camp could only assume that their leader had decided to spend the winter at the mid-ice camp. It was not until May 12 that the truth was discovered. Wegener's body was found under several feet of snow 118 miles inland, about halfway between Eismitte and the base camp, the spot marked by two skis. His body had been carefully sewn up in two sleeping bag covers by his faithful companion, the Greenlander Rasmus Villumsen, who vanished on the inland ice. Sorge and others surmised that Wegener's heart had failed in the high-elevation exertion and extreme cold. His body was left in the Greenland ice cap.

A year later, in 1932, the widow Else Wegener wrote of her husband: "Now he lies in the land to whose exploration he devoted so many years of his life, a land to which he was ever attracted both by its scientific problems and the grandeur of the natural surroundings, in which he alone can live who is prepared to risk all else for the sake of self-preservation. Above his own safety he ranked that of his comrades, and when that was assured, his scientific work. He would not stay where he could have spent the winter in comparative security but where his scientific plans could not be carried out. He went out into the winter night and succumbed to its forces. But his death is consecrated by the nobility of his aims."

More than 30 years later—in the 1960s—scientists confirmed Alfred Wegener's theory of continental drift. It would be 30 years more—the 1990s—before the scientific contributions of Ernst Sorge were fully recognized with another revolutionary concept: abrupt climate change.

Sorge probably would not have been surprised by the pace of events. Reviewing his findings for the Geographical Society in 1932, he observed that, contrary to his own expectations, the expedition had not "mastered the main difficulties" in measuring and understanding the great ice cap. "It seems to me," he said, "that for a long time to come this will be the experience of all Greenland expeditions: results that have been attained will be the source of new problems."

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