Ice Ages Solving The Mystery – J Imbrie

Because these geometrical factors could be de¬ rived from Pilgrim’s results, Milankovitch concluded that it should also be possible to describe mathematically the distribu¬ tion of solar radiation onto the surface of the planets. Although simple in principle, the task of making these calcula¬ tions proved to be enormously difficult in practice. For all of the planets are constantly spinning, revolving, wobbling and tilting in a crazy celestial dance, every movement of which has some effect on the radiation they receive from the sun.

But Milankovitch was 32 years old and confident of his powers. Later he wrote: “I set out on this hunt in my best years. Had I been somewhat younger I would not have possessed the necessary knowledge and experience …. Had I been older I would not have had enough of that self-confidence that only youth can offer in the form of rashness.”

At first, Milankovitch’s investigations went well. “But in trying to penetrate more deeply into the problem, I ran into difficulties and could get no further,” he wrote later. “Then [in 1912] the First Balkan War broke out. The Danube division of the Serbian Army, to whose staff I had been assigned, crossed the border of what was then the Turkish Empire early in the morning and was planning to capture Starac Mountain.”

As the young mathemati¬ cian watched the Serbian troops fight their way toward the sum¬ mit of the mountain, his thoughts turned to his own scientific attack, and the theoretical obstacles he had been unable to sur¬ mount. Then, as the Serbian regiment took the summit of Starac Mountain, the solution to his mathematical difficulties flashed into his mind, and he “conquered a mountaintop” on his own internal battlefield.

Two days later, the Turks were defeated. A cease-fire ensued, and Milankovitch was able to return to his private battle in the library in Belgrade. Although his progress now was rapid, he realized that it would be several years before his second major objective was attained. Keenly aware of the uncertain political atmosphere in the Balkans, he decided that he should go no further with his calculations until he had set down on paper the results he had obtained thus far. These were published as three short treatises during the years 1912 and 1913.

Early in 1914, Milankovitch published another article, “On the Problem of the Astronomical Theory of the Ice Ages.” Written in Serbian, and appearing in the midst of political turmoil in Europe, this article Ice Ages: Solving the Mystery remained in scientific obscurity for many years.

1: Louis Agassiz and the Glacial Theory 19 2: The Triumph of the Glacial Theory 33 3: Exploring the Ice-Age World 47 PART II: EXPLAINING THE ICE AGES 4: The Ice-Age Problem 61 5: Birth of the Astronomical Theory 69 6: The Astronomical Theory of James Croll 77 7: Debate Over Croll’s Theory 89 8: Through Distant Worlds and Times 97 9: The Milankovitch Controversy 113 10: The Deep and the Past 123 11: Pleistocene Temperatures 135 12: Milankovitch Revival 141— 13: Signal from the Earth 147 14: Pulsebeat of Climate 153 15: Pacemaker of the Ice Ages 161 PART III: ICE AGES OF THE FUTURE 16: The Coming Ice Age 177 EPILOGUE: The Last Billion Years of Climate 189 APPENDIX: Chronology of Discovery 195 SUGGESTED READING 203 BIBLIOGRAPHY 204 INDEX 215 ‘ ■ .

PREFACE Knowledge that the world once endured an ice age has been widespread for more than a century. Indeed, the concept is now so familiar that nearly every winter storm prompts dra¬ matic headlines: Is a new ice age upon us? This book tells the story of the ice ages—what they were like, why they occurred, and when the next one is due. It is a tale of scientific discovery, and therefore a book about people—about the astronomers, geochemists, geologists, paleontologists, and geophysicists from a dozen countries who have been engaged for nearly a century and a half in the search for a solution to the ice-age mystery.

We are indebted to many people for their advice and assis¬ tance in the preparation of this book. In particular we wish to thank Vasko Milankovitch for sharing with us his memories of his father, Milutin Milankovitch. Tatomir P. Angelitch of the Serbian Academy of Sciences and Arts was kind enough to pro¬ vide us with a complete list of Milankovitch’s publications. Bar¬ bara Gronquist translated many passages from the German. Gordon Craig of the University of Edinburgh helped locate information about James Croll.

The studies by Albert V. Ca- rozzi of the University of Illinois were an invaluable guide to the early development of the glacial theory. Catherine Krause located obscure sources that contributed greatly to this book. Many people put their personal recollections at our disposal. Among them were William A. Berggren, Wallace S. Broecker, Rose Marie Cline, Cesare Emiliani, Samuel Epstein, David B.

Ericson, Rhodes W. Fairbridge, James D. Hays, George J. Ku- kla, Robley K. Matthews, Neil D. Opdyke, Nicholas J. Shack- leton, and Manik Talwani.

This is a short excerpt from the opening of “” by Unknown, quoted for review and introduction purposes. All rights belong to the copyright holders.

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