Climate Shift Helped Destroy China's Tang Dynasty

The first two periods occurred at key moments during the last Ice Age, while the last ran from around 700 to 900. Each of these monsoon shifts coincided with what was, relative to the climate epoch, unusually cold weather.

The twilight of the Tang began in 751, when the imperial army was defeated by Arabs.

But what eventually destroyed the dynasty were prolonged droughts and poor summer rains, which caused crop failure and stoked peasants' uprisings.