Diving into origins of agriculture

Sediments from Lake Suigetsu (pictured) in Japan indicate stable climate led to origin of agriculture.

Archaeologists have argued about the origins of agriculture for well over a century. We know, for example, that farming began in many locations, among them the Middle East, South Asia, Northern China, and Central America, at various times after 10,000 BC. Until recently, there was increasing agreement that abrupt climate change and drought – which brought about a food shortage crisis – drove humans to adopt agriculture. But newly acquired climatic data from Japan has cast doubt on this scenario.

A team of researchers headed by Takeshi Nakagawa of the Ritsumeikan Museum have studied climate change using cores in Lake Suigetsu, about 150km north-north east of Osaka. The lake has yielded pollen grains in layered sediments of the lake dating from about 16,000 to c. 8,000 BC, a sequence that straddles the earliest farming in this area.

What Nakagawa and his colleagues found was that the first attempts of domesticating plants, and constructing settlements based on agriculture, coincided with periods of relatively warm, and more importantly, stable climate. They noted that although the transition from the Ice Age to the post-glacial age veered constantly between stable regimens and unstable intervals, the domestication of plants did NOT start when the warm climate was established around 13,000 BC. Instead, it occurred when the climate stopped oscillating in short intervals and large amplitudes, at around 12,000 BC.

Why? Subsistence agriculture is a risky enterprise. It requires planning – impossible in unstable climatic conditions, when hunting and foraging are far more effective. Thus, argue the Suigetsu scholars, their fine-grained research, collected over more than 20 years, suggests that current theories may be wrong. It seems that it was the warm plus stable conditions that were the decisive catalyst for agriculture. The Suigetsu climatic data will ensure that the debate over agricultural origins will continue for many more generations.

Image: aerial shot of Japan’s Mikata five lakes with Lake Suigetsu as the largest one in the middle. Credit: Ministry of Land, Infrastructure, Transport and Tourism.