Younger Dryas Cold Snap

One of the joys about cutting-edge studies that merge scientific data with the discipline of history is the chance to answer questions that we never thought we’d be able to. This photo of Greenland’s ice sheet gets at the way that climate scientists are trying to understand one of the most transformative aspects of earth life: the human invention of agriculture.

Gone is the notion that small bands of wandering hunter-gatherers rapidly settled down in large numbers to sedentary villages where they cleared the wilderness and cultivated grains. Anthropologists and historians now acknowledge that in the centuries around 12,000 BCE, some humans formed large settled communities (often seasonally) and survived off of particularly abundant ecosystems by diversifying their hunting and foraging skills, and cultivating the landscape — not through monoculture seed planting, but through other methods of encouraging propitious foraging.

But what led to the beginnings of such sedentary, pre-agriculture groups — and what caused some of them, centuries later, to turn to farming? The jury is out, but a major hypothesis is a weather period known as the Younger Dryas Cold Snap (10,500-9,600 BCE). It interrupted the warming trend begun around 13,000 at the end of the last ice age. And although it didn’t last long in geological terms — a mere 1,200 years — temperatures on earth plummeted as much as 8 degrees Celsius, or 14.5 degrees Fahrenheit. Some climate evidence suggests that the cooling only applied to the northern hemisphere, but the change wherever it happened was intense.

And the Younger Dryas Cold Snap seems to have run concurrent with other changes — like the decline of many giant fauna (wooly mammoths) and the vanishing of the Clovis populations (the Clovis people inhabited the Americas). Historians can’t decipher correlation versus causation with these trends, but one of the things that scholars notice is the emergence of very large groups of settled people who eventually turned to agriculture — documented well in places like Abu Hureyra in the former Mesopotamia). Could the scarcity of resources caused by the changing weather have prompted this invention?