Monsoon link to fall of dynasties

The demise of some of China's ruling dynasties may have been linked to changes in the strength of monsoon rains, a new study suggests.

The findings come from 1,800-year record of the Asian monsoon preserved in a stalagmite from a Chinese cave.

Weak - and therefore dry - monsoon periods coincided with the demise of the Tang, Yuan and Ming imperial dynasties, the scientists said.