Feature: A historical perspective on climate change

From 11,600 to 8,200 years ago, the climate became warmer and in the Eastern Mediterranean, wetter. It was during this period that successive generations of foragers, who took advantage of the well-watered habitats, adopted farming as their dominant mode of obtaining food. This marked the most remarkable revolutionary achievement of humankind—the invention of agriculture.

Life has never been the same since. Villages coalesced to form corporate village communities governed by councils or chiefs. Afterwards, conglomerates of farming communities merged into kingdoms, while those who managed cattle, sheep and goats became herders and roamed the rain-fed grasslands outside the river valleys preferred by farmers.

The effect of climate change on humanity under this new agrarian regime with its politically more complex organization assumed a new turn. This has been mostly due, in part, to the nature of the agrarian ecology and economic growth potential. Agricultural yields fluctuated annually, in part because of interannual variability in rainfall, but more importantly, they also varied responding to decadal and centennial changes in climatic conditions, which influenced both the flow of rivers and rainfall in the grasslands. . . .

By the 5000 B.C. the early agrarian States had developed into the world’s first great civilizations in Egypt, Mesopotamia, and India. But by around 4200 B.C., an abrupt turn of climate led to dramatic changes all over the world.