Some 100 years ago, environmental determinism was a key component of geographical study, and climatic change was seen as a potent driving force behind the rise and fall of cultures.
Elsworth Huntington, for example, was intrigued about Central Asia and the evidence for decayed civilisations and migration. He tried to reconstruct cycles of droughts over the past millennia to explain them. The anarchist Prince Kropotkin, around the same time, argued that climatic deterioration was the result of increasing aridity in the period since the last ice age.
Some archaeologists were also attracted to climatic determinism; notable here was Gordon Childe, who saw it as the trigger for the adoption of domestication and the start of agriculture. In general, in the second half of the 20th century, climatic determinism became a subject of ridicule, though some climatologists could see that phases of flood, storm and drought had an impact on past societies. On the other hand, in the second half of the century, climatology itself underwent a revolution and became a major focus for interdisciplinary research.
This was because of two developments. The first was the dating revolution.
New techniques, based on radiocarbon, uranium series and thermoluminescence, allowed relatively precise dates to be determined for a wide range of materials. This was crucial if one wanted to establish the temporal correspondence between natural climatic events and cultural changes.
Second, scientists were able to determine the environmental changes by taking cores from the ocean floors, lakes and ice caps, and by sampling thick sequences of sediments preserved in environments such as loess sheets and caves. So we now have accurately dated, detailed sequences of environmental change. The techniques have also shown that the changes have been of great frequency, considerable degree and, least expected, great rapidity. The time is thus ripe for a reconsideration of the role of climatic change in history and prehistory.
This is what that prolific archaeologist Brian Fagan has attempted.
Combining his expertise in prehistory with all the new information produced by palaeoclimatologists, he seeks to show how the transformation of global climates since the peak of the last ice age (some 20,000 years ago) and the fluctuations of the relatively clement years of the Holocene have provoked humans to adapt and display resilience.
He considers the tundra life of Cro-Magnon people, the migration of Asians across Beringia to the Americas, the impact of the Younger Dryas cold and drought on the peoples of the Middle East, the adoption of domestication, the rise and fall of cities in Mesopotamia, the great greening of the Sahara in the early to mid-Holocene, the impact of El Nino, the great droughts that afflicted the peoples of the American southwest before the arrival of the Europeans, and the consequences of the Little Ice Age for Europe's rural inhabitants.
This is a book with a grand sweep - it shows a good command of the new climatology - and it is clear and accessible. It is a survey that covers a big span of time, many cultures and many parts of the world. It has a message with respect to the climatic future - adapt or perish.
Andrew Goudie is master of St Cross College, Oxford.
The Long Summer: How Climate Changed Civilization
Author - Brian Fagan
Publisher - Granta
Pages - 284
Price - £20.00
ISBN - 1 86207 644 8