The role of climatic change in human history remains open to question, due in large part to scant data. Fagan, professor of archeology at UC Santa Barbara, contributes substantively to the increasingly urgent debate. Contending with the dearth of accurate weather records from a few parts of the world, for little over a century Fagan (Floods, Famines, and Emperors: El Ni o and the Fate of Civilizations) draws discerning connections between an amazing array of disparate sources: ice cores, tree rings, archeological digs, tithing records that show dates of wine harvests, cloud types depicted in portraits and landscapes over time. He details human adaptation to meteorologic events for example, the way the Dutch, in the face of rising sea levels, engineered sea walls and thus increased their farmland by a third between the late 16th and early 19th centuries. Explanations of phenomena like the North Atlantic Oscillation (which ""governs... the rain that falls on Europe"") lucidly advance Fagan's conviction that, though science cannot decide if the current 150-year warming trend (with one slight interruption) is part of a normal cycle, we should err on the side of caution. His study of the potential for widespread famine further bolsters his nonpartisan argument for a serious consideration of rapid climatic shifts. But Fagan doesn't proffer a sociopolitical polemic. He notes that we lack the political will to effect change, but refrains from speculating on future environmental policy. Illus. not seen by PW. (Mar. 1) Forecast: This topical book will appeal to fans of John McPhee, as well as to science and history scholars. With publicity targeted at the coasts (author tour in L.A., San Francisco and N.Y.; a talk at N.Y.'s Museum of Natural History), a forthcoming review in Discovery magazine and Fagan's enthusiastic readership, it should sell well.