It was climate change, not the Mongol insurgency led by Genghis Khan that caused the demise of Central Asia’s river civilisations in the early 13th century, new research suggests.
The lands around the Aral Sea basin were once home to advanced civilisations that for centuries used floodwater irrigation to farm. However, research led by the Lincoln Centre for Water and Planetary Health found that the abandonment of irrigation systems matches a phase of riverbed erosion between the 10th and 14th centuries that coincided with a dry period with low river flows.
Mark Macklin, distinguished professor of river systems and global change at the University of Lincoln said: “It was climate change, not Genghis Khan, that was the ultimate cause of the demise of Central Asia’s forgotten river civilisations.”
The team found that Central Asia recovered quickly following Arab incurrences in the 7th and 8th centuries because of wet conditions that favoured floodwater farming. “But prolonged drought during and following the later Mongol destruction reduced the resilience of local populations and prevented the re-establishment of large-scale irrigation-based agriclture," Macklin explains.
The research focused on the archaeological sites and irrigation canals of the Otrar oasis, a UNESCO World Heritage site that was once a Silk Road trade hub located at the meeting point of the Syr Darya and Arys rivers in present-day southern Kazakhstan. The researchers investigated the region to determine when the irrigation canals were abandoned and studied the past dynamics of the Arys river, whose waters fed the canals.
The findings have been published in a research article in the PNAS (Proceedings of the National Academy of Sciences) entitled “A hydromorphic reevaluation of the forgotten river civilisations of Central Asia”.
