The Meteorologist Who Started a Revolution

The meteorologist who started a revolution. (German Alfred Wegener)(The First Fifty Years). Patrick Hughes. Weatherwise v51.n1 (Jan-Feb 1998): pp38(4).

Abstract:

Alfred Wegener was a German visionary meteorologist whose theory of continental drift became the foundation of modern concepts on the origin of continents and oceans. His theories were initially rejected but were later accepted by the scientific community in the face of mounting evidence.

Full Text :

Utter, damned rot!" said the president of the prestigious American Philosophical Society.

"If we are to believe [this] hypothesis, we must forget everything we have learned in the last 70 years and start all over again," said another American scientist.

Anyone who "valued his reputation for scientific sanity" would never dare support such a theory, said a British geologist.

Thus did most in the scientific community ridicule the concept that would revolutionize the earth sciences and revile the man who dared to propose it, German meteorological pioneer and polar explorer Alfred Wegener. Science historians compare his tribulations with those of Galileo.

Geographic Jigsaw Puzzle

"Doesn't the east coast of South America fit exactly against the west coast of Africa, as if they had once been joined?" wrote Wegener in December 1910. "This is an idea I'll have to pursue."

The following fall Wegener came across scientific papers promoting the prevailing theory that Africa and South America had once been connected by a continentsize land bridge that had since sunk into the sea. They cited as evidence fossils of identical animals that had lived in both areas simultaneously hundreds of millions of years ago.

Wegener was fascinated and searched out other papers about such continental coincidences. As he read, his earlier conjecture that the continents themselves had once been joined became a firm conviction he would boldly champion for the rest of his life.

Just a few months later, on January 6, 1912, Wegener startled a meeting of the Geological Association in Frankfurt with his radical theory. Dismissing the concept of sunken land bridges, he proposed instead a grand vision of drifting continents and widening seas to explain the evolution of Earth's geography. Four nights later he made a similar presentation to the Society for the Advancement of Natural Science in Marburg, Germany.

Wegener had launched a revolution - and he knew it. Just two weeks earlier, he had written his future father- in-law, eminent climatologist Vladimir Koppen, "If it turns out that sense and meaning are now becoming evident in the whole history of the earth's development, why should we hesitate to toss the old views overboard?"

Resume of a Revolutionary Alfred Wegener studied the natural sciences at the University of Berlin, receiving a doctorate in astronomy in 1904. He did not pursue a career in astronomy, however, but turned instead to meteorology.

In 1905 Wegener went to work at the Royal Prussian Aeronautical Observatory near Berlin, where he used kites and balloons to study the upper atmosphere. Thanks to his upper-air work, Wegener was invited to join a 1906 Danish expedition to Greenland's unmapped northeast coast. During this expedition he became the first to use kites and tethered balloons to study the polar atmosphere.

When he returned to Germany, Wegener's Arctic research earned him a position at the University of Marberg where, beginning in 1909, he lectured on meteorology, astronomy, and "astronomic-geographic position-fitting for explorers."

Both students and professors were impressed by the clarity of the young meteorologist's thinking, by his ability to explain difficult concepts in simple terms, and by the intuitive leaps of his nimble mind.

"With what ease he found his way through the most complicated work of the theoreticians, with what feeling for the important point!" a somewhat-awed colleague would later write. "He would often, after a long pause for reflection, say 'I believe such and such' and most times he was right, as we would establish several days later after rigorous analysis."

In 1912, the year of his continental-drift presentations, Wegener returned to Greenland. His four-man expedition was the first to overwinter on the ice cap. The following spring, they barely survived the longest crossing of the great ice sheet to that time, traversing 750 miles of barren snow and ice rising to heights of 10,000 feet.

During these perilous adventures, Wegener collected volumes of unique scientific data. The resulting publications established him as one of the world's leading experts on polar meteorology and glaciology. According to fellow meteorologist and Greenland explorer Dr. Johannes Georgi, Wegener was the first to trace storm tracks over the ice cap.

When he returned to Marberg, Wegener resumed work on continental drift, marshaling all the scientific evidence he could find to support his theory.

"One day a man visited me whose fine features and penetrating blue-gray eyes I was unable to forget," the great German geologist Hans Cloos later recalled. "He spun out an extremely strange train of thought about the structure of the earth and asked me whether I would be willing to help him with geological facts and concepts."

Using this interdisciplinary approach, Wegener wrote one of the most influential and controversial books in the history of science: The Origin of Continents and Oceans, published in 1915. Because of the First World War, Wegener's book went unnoticed outside Germany. In 1922, however, a third (revised) edition was translated into English, French, Russian, Spanish, and Swedish, pushing Wegener's theory of continental drift to the forefront of debate in the earth sciences.

The Origin of Continents and Oceans

Wegener began by demolishing the theory that large land bridges had once connected the continents and had since sunk into the sea as part of a general cooling and contraction of the earth. He pointed out that the continents are made of a different, less dense rock (granite) than the volcanic basalt that makes up the deep-sea floor, in which Wegener proposed the continents floated somewhat like icebergs in water. He also noted the continents move up and down to maintain equilibrium in a process called isostasy. As an example he cited the sinking of Northern Hemisphere lands under the weight of continental ice sheets in the last ice age, and their rise since the ice melted some 10,000 years ago.

Given the difference in density between continents and sea floor, plus the process of isostasy, Wegener reasoned that if continent-size land bridges had existed and somehow been forced to the ocean bottom, they would have "bobbed-up" again when the force was released. Therefore, since fossil and geological evidence clearly showed the continents were once connected, the only logical alternative was that the continents themselves once had been joined and had since drifted apart.

Wegener also offered a more plausible explanation for mountain ranges. According to the cooling, contracting-Earth theory, they formed on the earth's crust as wrinkles form on the skin of a drying apple. If this were so, however, they should be spread evenly over the earth; instead mountain ranges occur in narrow bands, usually at the edge of a continent. Wegener said they formed when the edge of a drifting continent crumpled and folded as when India hit Asia and formed the Himalayas.

He also noted that when you fit Africa and South America together, mountain ranges (and coal deposits) run uninterrupted across both continents, writing: "It is just as if we were to refit the torn pieces of a newspaper by matching their edges and then check whether the lines of print ran smoothly across. If they do, there is nothing left but to conclude that the pieces were in fact joined in this way."

In his third edition, Wegener cited geological evidence that some 300 million years ago all the continents had been joined in a supercontinent stretching from pole to pole. He called it Pangaea (all lands), and said it began to break up about 200 million years ago, when today's continents started moving to their current positions.

Hans Cloos provided the best summary of Wegener's revolutionary theory: "It placed an easily comprehensible, tremendously exciting structure of ideas upon a solid foundation. It released the continents from the earth's core and transformed them into icebergs of gneiss [granite] on a sea of basalt. It let them float and drift, break apart and converge. Where they broke away, cracks, rifts, trenches remain; where they collided, ranges of folded mountains appear."

The Wrath of Science

Except for a few converts, and those like Cloos who couldn't accept the concept but was clearly fascinated by it, the international geological community's reaction to Wegener's theory was militantly hostile. American geologist Frank Taylor had published a similar theory in 1910, but most of his colleagues had simply ignored it. Wegener's more cogent and comprehensive work, however, was impossible to ignore and ignited a firestorm of rage and rancor. Moreover, most of the blistering attacks were aimed at Wegener himself, an outsider who seemed to be attacking the very foundations of geology.

Because of this, Wegener could not get a professorship at any German university. Fortunately, the University of Graz in Austria was more tolerant of controversy, and in 1924 it appointed him professor of meteorology and geophysics.

In 1926, Wegener was invited to an international symposium in New York called to discuss his theory. Though he found some supporters, many speakers were sarcastic to the point of insult. Wegener said little. He just sat smoking his pipe and listening. His attitude seems to have mirrored that of Galileo who, forced to recant Copernicus' theory that the Earth moves around the sun, is said to have murmured, "Nevertheless, it moves!"

Scientifically, of course, Wegener's case was not as good as Galileo's, which was based on mathematics. His major problem was finding a force or forces that could make the continents "plow around in the mantle," as one critic put it. Wegener initially suggested two candidates: centrifugal force caused by the earth's rotation, and tidal-type waves in the earth itself generated by the gravitational pull of the sun and moon.

He realized these forces were inadequate. "It is probable the complete solution of the problem of the forces will be a long time coming," he predicted in his last (1929) revision. "The Newton of drift theory has not yet appeared."

Wegener's final revision cited supporting evidence from many fields, including testimonials from scientists who found his hypothesis resolved difficulties in their disciplines much better than the old theories. Climatology was one such discipline. Fossils and geologic evidence show that most of the continents used to have startlingly different climates. Wegener thought continental drift was the key to these climatic puzzles, so he and Vladimir Koppen plotted ancient deserts, jungles, and ice sheets on paleographic maps based on Wegener's theory. Suddenly the pieces of the puzzles fell into place, producing simple, plausible pictures of past climates. Evidence of the Permo-Carboniferous ice-age era that peaked some 280 million years ago, for example, is scattered over almost half the earth, including the hottest deserts. On Wegener's map, however, it all clustered neatly around the South Pole - because Africa, Antarctica, Australia, and India then comprised a Southern Hemisphere supercontinent (Gondwanaland).

Wegener considered such paleoclimatic validation one of the strongest proofs of his theory. Conversely, continental drift has since become the organizing principle of paleoclimatology and other paleosciences.

Unfortunately, though Wegener's explanation of the Permo-Carboniferous ice age impressed even his most vocal critics, the merit of much of the rest of his supporting evidence was not widely recognized at the time. As a result, most geologists eventually dismissed his theory as "mere geopoetry."

Vindication of a Visionary

Despite general rejection, Wegener's compelling concept continued to attract a few advocates over the next several decades. Then, beginning in the mid-1950s, a series of confirming discoveries in oceanography and paleomagnetism finally convinced most scientists that continents do indeed move. And although the continents don't actually float and drift about in the seafloor as Wegener suggested, their movement is part of a grandscale process that causes mountain-building, earthquakes, volcanic eruptions, sea-level fluctuations, and apparent polar wandering as it rearranges Earth's geography.

Geologists call the process "plate tectonics," after the large moving plates that form the planet's outer shell. These plates carry both continents and sea floor, but unlike the sea floor, the less-dense, buoyant continents resist subduction into the mantle.

Thus, despite significant differences in detail, Alfred Wegener was right in most of his major concepts, and the term "continental drift" is widely used as a euphemism for plate tectonics. Geologists have also confirmed the accuracy of many of his paleogeographic reconstructions.

Ironically, though the lack of a credible driving force was the main objection to Wegener's theory, plate tectonics has been almost universally accepted despite the absence of scientific consensus as to its cause. Convection currents in the molten magma of the upper mantle are the favorite candidate; Wegener discussed this possibility in his 1929 revision.

During the last few decades, Alfred Wegener has finally gotten the recognition he deserves. Unfortunately, as with most visionaries, it must be posthumous praise.

Alfred Wegener died a hero's death in his beloved Greenland in 1930, after an incredible six-week trek battling blizzards with temperatures near -60 [degrees] F to rescue comrades trapped on the ice cap.

Wegener's friends built an ice-block mausoleum over his body and erected a 20-foot iron cross to mark the site. All have long since vanished beneath the snow to become part of the great glacier itself.

It is a most fitting resting place for this remarkable man who devoted much of his life to the study of that remnant of the last ice age and whose grand vision of moving continents provided the key to unlock the mysteries of more ancient glacial epochs.

PATRICK HUGHES is a Weatherwise contributing editor. This article appeared in the April/May 1994 issue