Climate Change May Have Caused an Abrupt Civilization Collapse on the Tibetan Plateau

Climate change may be responsible for the abrupt collapse of a civilization on the fringes of the Tibetan Plateau around 2000 BC. Scientists have discovered that cooling global temperatures may have pushed humans over the edge during that time period.

During the Holocene Climatic Optimum, our planet experienced a 4,000-year period of warm weather. During this time, ancient people on the Tibetan Plateau cultivated millet, their primary food source. However, researchers noticed that at archaeological sites in the Tibetan highlands, millet was rapidly replaced by wheat and barley as a food source. This was puzzling considering that the scientific consensus was the region's climate could have favored millet, due to its shorter growing season, over wheat or barley.

This is why the researchers decided to investigate a bit further. The scientists found that agronomists tended to use different measurements than archaeologists to determine whether crops could grow in cold, high altitude environments, like the Tibetan plateau. Knowing this, the scientists created a new model.

So what did they find? It turns out that abrupt climate cooling may be the reason why millet was rapidly replaced by wheat and barley, crops that can withstand freezing. In fact, it's likely that the early civilization at the time collapsed due to this climate cooling.

These days, though, the residents of the region are experiencing the opposite effect. The area is one of the places experiencing the most rapid climate warming on the planet. In fact, there are some areas in the southeastern plateau where temperatures are 6 degrees Celsius higher than they were 200 years ago.

The new findings don't just explain what occurred in the past, but could also be important for the future. As temperatures warm, inhabitants of the area may need to switch back to millet as a staple.

The findings are published in the journal Proceedings of the National Academy of Sciences.

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