Science Advances: advanced ancient Liangzhu civilisation vanished due to climate change.
An international team of scientists has shown that the Liangzhu culture, which existed more than five thousand years ago in eastern China, has disappeared due to climate change in the region. Although the ancient Chinese civilisation possessed quite advanced water management technology, it died due to severe flooding caused by abnormal monsoon rains. The findings are published in the journal Science Advances. The scientific work is summarised in a press release on Phys.org.
The ruins of the city of Liangzhu are located in the Yangtze River delta, about 160 kilometres southwest of Shanghai. About 5,300 years ago, a highly developed culture emerged that built large hydraulic structures, though with no mastery of metalworking. Liangju was a fortified city with a complex system of navigable canals, dams and reservoirs. The system covered large agricultural areas and allowed for cultivation throughout the year.
It is still not known exactly what caused the extinction of the ancient Chinese civilisation. Archaeologists have found no trace of military conflict, which rules out a human factor in the demise of the Liangzhu culture. The key to unlocking the fate of Liangzhu turned out to be the thin layer of clay that covered the ruins, indicating a possible connection to flooding on the Yangtze River or storm surges in the East China Sea.
Researchers analysed stalagmite samples from the Shennong and Jiulong Caves, located southwest of the Liangzhu excavation site. This allowed them to reconstruct climatic conditions in the region over the past few hundred thousand years from the carbon isotope composition of the sediments. The data show that 4324-4345 years ago was a period characterized by extremely high precipitation. The exact dating was done by analyses of uranium and thorium isotopes with an accuracy of plus or minus 30 years.
The heavy monsoon rains probably caused the Yangtze and its branches to flood heavily, so that even the elaborate system of dams and canals could no longer withstand the masses of water that destroyed the city of Liangju and forced people to flee. The extremely humid climatic conditions persisted for another three hundred years.
