_The Long Summer_ by Brian Fagan is in essence a follow up of his excellent earlier work, _The Little Ice Age_, a book that explored the effect of a particular climatic episode on European civilization between the years 1300 and 1850. Fagan expanded his focus greatly in _The Long Summer_ as in this work he analyzed the effects of various climatic events since 18,000 B.C. on the course of Stone Age life, early farming societies, and the evolution of civilizations in Europe, southwest Asia, north Africa, and the Americas, covering climatically-influenced human history from the settlement of the Americas to the origins of the Sumerians to the conquest of Gaul by Rome (which was fascinating) through the end of the Mayan and Tiwanaku civilizations (in Central and South America respectively). As in _The Little Ice Age_, Fagan dismissed both those who discounted the role climatic change had played in transforming human societies and those who believed in environmental determinism (the notion that climate change was the primary cause of major developments in human civilization).
Fagan provided many examples of climatic change affecting human history. Between 13,000 and 8,000 B.C. Europe became covered in forest thanks to warming climates and retreating glaciers. This climatic change - and resulting alteration in the ecology of the region - lead to the extinction of the large and medium-sized herd animals that were the favored prey of the Cro-Magnons (such as the mammoth, woolly rhinoceros, giant deer, and reindeer) and their replacement by smaller, generally more dispersed game like red deer, wild boar, and aurochs. Not only did this change in fauna lead to a change in hunting techniques, it also lead to an increased reliance on plant food and in general a much broader diet that included nuts, seeds, tubers, fruit, and fungi. Other changes included increased mobility - and the end of cave art, as tribes and bands were no longer attached to certain areas - and the development of the bow and arrow, much more effective in dense forest against solitary, skittish prey.
While Europeans adjusted to a world without megafauna, by 11,000 B.C. a group known as the Kebarans became dependent upon a relatively moist area of oak and pistachio forests that extended from modern Israel through Lebanon and into much of modern Syria. Though not developing agriculture per se, as they did not plant crops but rather relied on wild plants, they nevertheless developed some of the early signs of agriculture, such as pestles, mortars, and other tools to process the seeds and nuts that they harvested, the Kebarans relying on the millions of acorns and pistachios that they collected each year, supplemented by wild grass seeds and wild gazelles.
While the development of permanent Kebaran villages anchored to groves of nut-bearing trees and grass stands was a response to climatic and ecological changes brought on by the end of the Ice Age, their eventual end was also largely brought upon by the onset of a series of intense droughts thanks to a remarkable and seemingly distant event around 11,000 B.C.; the draining of the immense Lake Agassiz, a huge meltwater lake that lapped the retreating Laurentide ice sheet for 1,100 km in modern day Canada and the U.S. The lake rose so much that it eventually burst its banks and flooded into what is now Lake Superior and then onto to the Labrador Sea. So much Agassiz meltwater floated atop the dense, salty Gulf Stream that for ten centuries that conveyor of warm, moist air to Europe ceased, among other things plunging southwestern Asia into a thousand year drought. This drought eliminated the groves that the Kebarans depended upon, ending their prehistoric society, though not before the first experiments with cultivating wild grasses. Eventually villages arose that existed primarily dependent and then completely dependent upon cereal agriculture, on grain crops planted and harvested by the people themselves. In such places as Abu Hureyra in modern Syria full-fledged farming arose by 9500 B.C. as a response to drought, to the end of the oak-pistachio belt and the decline of game.
Just as drought lead to early experiments with pre-agricultural communities and then to the actual cultivation of grains, it may have also lead to the domestication of wild goats and sheep in southwestern Asia and of cattle in what would become the Sahara Desert. The arid conditions for instance in southwestern Asia between 11,000 and 9500 B.C. lead to a concentration of game and of humans around the increasingly few permanent water sources, an event that would allow hunters to intimately know individual herds, even individual animals, allowing for these ancient humans to learn how to control the few key members of herds, to selectively cull undesirable members to change the characteristics of that herd's offspring, and how to eventually capture and pen some or all of the herd for later consumption.
It was amazing to me how different the climate and terrain of ancient man truly was. Those who discount the effects of climatic change upon human history should consider how different the world of 6200 BC was. In this year - the time of the famed flat-roofed settlement of Catalhoyuk in central Turkey - farmers lived on the shores of the vast, brackish Euxine Lake to the north of the Anatolian plateau (what would become the Black Sea) and the Laurentide glacier was still retreating in northern Canada. In this year (more or less) began what has been called the Mini Ice Age as vast amounts of Laurentide meltwater suppressed the Gulf Stream, plunged Europe into colder and drier conditions, produced a profound drought in the Mediterranean, and caused ocean waters to rise so that Britain was finally severed from the continent.
Also quite interesting were the several prehistoric societies Fagan touched upon, such as the Kebarans, the `Ubaid people of 5800 B.C. southern Mesopotamia (they predate the Sumerians), the Linearbandkeramik communities of 5600 B.C. Europe, and the early fifth millennium B.C. Badarians of the Nile Valley, groups I was completely unfamiliar with.
