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.

Looks at the origins of previous ice ages, the circumstances that lead up to glaciation, climate changes, and the possibility of an ice age or a less severe period of increased cold in the future.

It is not possible to understand the present or future climate unless scientists can account for the enormous and rapid cycles of glaciation that have taken place over the last million years, and which are expected to continue into the future. A great deal has happened in the theory of the ice ages over the last decade, and it is now widley accepted that ice ages are driven by changes in the Earth's orbit. The study of ice ages is very inter-disciplinary, covering geology, physics, glaciology, oceanography, atmospheric science, planetary orbit calculations astrophysics and statistics.

"John and Mary Gribbin tell the remarkable story of how we came to understand the phenomenon of Ice Ages, focusing on the key personalities obsessed with the search for answers. How frequently do Ice Ages occur? How do astronomical rhythms affect the Earth's climate? Have there always been two polar ice caps? Is it true that tiny changes in the heat balance of the Earth could plunge us back into full Ice Age conditions? With startling new material on how the last major Ice Epoch could have hastened human evolution, Ice Age explains why the Earth was once covered in ice - and how that made us human."--BOOK JACKET.

Until about 13,000 years ago, North America was home to a menagerie of massive mammals. Mammoths, camels, and lions walked the ground that has become Wilshire Boulevard in Los Angeles and foraged on the marsh land now buried beneath Chicago's streets. Then, just as the first humans reached the Americas, these Ice Age giants vanished forever. In Once and Future Giants, science writer Sharon Levy digs through the evidence surrounding Pleistocene large animal ("megafauna") extinction events worldwide, showing that understanding this history--and our part in it--is crucial for protecting the elephants, polar bears, and other great creatures at risk today. These surviving relatives of the Ice Age beasts now face the threat of another great die-off, as our species usurps the planet's last wild places while driving a warming trend more extreme than any in mammalian history. Deftly navigating competing theories and emerging evidence, Once and Future Giants examines the extent of human influence on megafauna extinctions past and present, and explores innovative conservation efforts around the globe. The key to modern-day conservation, Levy suggests, may lie fossilized right under our feet.