Today China is the world's biggest consumer of wheat. But it wasn't always that way.
Wheat only came to the area now known as northern China toward the end of the Neolithic (新石器)period, some 4,600 years ago. Initially, wheat didn't seem to be so delicious and had been treated as a crop of desperation rather than a cooking delight. The first farmers of northern China primarily grew millet (粟), starting as early as 11,500 years ago. By the time of the Tang dynasty, wheat had replaced millet, becoming a major crop. But relatively little was known about exactly why this shift occurred.
In an attempt to track the answer, I accumulated (积累)a collection of nearly 1,200 data points covering more than 50 sites from the mid-Neolithic, about 9,000 years ago, to the collapse of the Eastern Han dynasty in 220 AD. The sites were across 8 modem provinces, ranging from Gansu province in the northwest to Shandong province in the east.
One possible explanation is a major climate shift, called the Holocene Event 3, which happened 4,000 to 4,500 years ago. At that time, the climate became colder and drier across continents, causing damage to crop production.
On top of this, the late Neolithic period was also a time of rapid population growth around the world. With an ever-increasing population and unsteady crop production, it is reasonable to assume that Neolithic farmers in northern China were struggling.
Wheat, it turns out, actually needs more water than millet, making it seem a poor choice for a dry period of history. But importantly, it can be sowed after millet has been harvested. That, we think, is the most likely reason why the people across northern China started to grow wheat.
From more extreme weather to changing coastlines, climate change has always brought unexpected and sometimes dramatic changes to societies. In this instance, the consequence of the Holocene Event 3 in northern China proved, eventually, delicious.
