In this engrossing and accessible book, Doug Macdougall explores the causes and effects of ice ages that have gripped our planet throughout its history, from the earliest known glaciation—nearly three billion years ago—to the present. Following the development of scientific ideas about these dramatic events, Macdougall traces the lives of many of the brilliant and intriguing characters who have contributed to the evolving understanding of how ice ages come about. As it explains how the great Pleistocene Ice Age has shaped the earth's landscape and influenced the course of human evolution, Frozen Earth also provides a fascinating look at how science is done, how the excitement of discovery drives scientists to explore and investigate, and how timing and chance play a part in the acceptance of new scientific ideas.
Macdougall describes the awesome power of cataclysmic floods that marked the melting of the glaciers of the Pleistocene Ice Age. He probes the chilling evidence for "Snowball Earth," an episode far back in the earth's past that may have seen our planet encased in ice from pole to pole. He discusses the accumulating evidence from deep-sea sediment cores, as well as ice cores from Greenland and the Antarctic, that suggests fast-changing ice age climates may have directly impacted the evolution of our species and the course of human migration and civilization. Frozen Earth also chronicles how the concept of the ice age has gripped the imagination of scientists for almost two centuries. It offers an absorbing consideration of how current studies of Pleistocene climate may help us understand earth's future climate changes, including the question of when the next glacial interval will occur.
With all the concern about global warming, it may be surprising to read that "today's climate is just a geologically short warm spell in a continuing ice age." In this lucid and informative book, Macdougall (A Short History of Planet Earth), an earth science professor at the Scripps Institution of Oceanography, introduces some of the scientists who have studied the Earth's ice ages, including the celebrated 19th-century naturalist Louis Agassiz, who put forth the theory, revolutionary at the time, of a global ice age; the amateur scientist James Croll, who propounded the idea that cycles of glacial and interglacial climates are related to changes in Earth's orbit around the Sun; and J. Harlan Bretz, who studied the catastrophic glacial flood that produced the "Channeled Scablands" of Washington state. That glaciers once extended from the North Pole to the Mediterranean was a fact accepted only gradually, and Macdougall examines in detail the clues rock formations, glacial deposits, fossils and sediment cores that scientists have used to prove the existence of continental ice sheets, as well as to study them. He closes with a discussion of our current ice age, suggesting that global warming may bring it to a premature end. Some of the science can get a bit technical, but Macdougall's readable style makes it accessible to the interested layperson. Illus. not seen by PW.
Fascinating, well written book.
Fascinating, well written book.