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15 of 15 people found the following review helpful:
5.0 out of 5 stars
Glacial gymnastics, 14 Jun 2004
Among the many mysteries surrounding human evolution is the "kick start" our cognitive abilities achieved compared with the other primates. This rapid enhancement has been attributed to many causes, new tool use Calvin, whose neuroscience qualifications are impeccable, offers a fresh view. In so doing, he doesn't cease speculating on how we got to be how we are, but takes a further step in suggesting where we might be going. And how to avoid getting there. The human brain is neither an inevitable progression, nor a divine gift, he argues. It's the result of raindrops ceasing to fall on our heads. Climate, he argues, made us what we are. Equally, it may undo us.Calvin sets the scene at the time when climate changes forced the shrinking of the forest cover in East Africa. Our barely upright ancestors, in coping with the changing environment, learned survival skills on the savannah, then spread out over the globe. During our migrations, various new climatic conditions were being established . The suture of Central America joining North and South America set new wind and current patterns around the globe. The resulting North Atlantic Current [the Gulf Stream] and the temperature and salinity exchanges in that ocean have proven a major factor in climate. Calvin examines what is known about these mechanisms and the impact of variations. The most significant new knowledge refutes the established idea that climate changes gradually. Sudden, wild "flips" of temperature, rainfall and snow cover are now seen as the norm, not as aberrations. Change isn't on the order of centuries, but in years. Calvin's technique of presenting his ideas is as novel as his thesis. Each chapter is an "electronic seminar" with "lectures" and questions arriving for the reader's scrutiny from locations all over the globe. Calvin thus presents himself as a field investigator, relating what on-site researchers are revealing. And much, indeed, is being exposed for assessment. Records from Greenland ice and other sources indicate "chattering" patterns of weather change. These and other finds are related and discussed. And presented for the reader to ponder. If the text doesn't give you reason to pause and reflect, there are numerous striking photographs and diagrams to seize your attention. A Glossary and excellent Further Reading section complete a work of striking significance. If you delay reading this, you may find yourself having to don mittens to take it up. Read it NOW! [stephen a. haines - Ottawa, Canada]
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