New research has shown that decline of central Asian river civilizations was due to climate change and not Mongol invasion as widely believed.
Researchers conducted analysis on the region and found that falling water levels may have led to the fall of civilizations around the Aral Sea Basin, as they depended on the water for irrigation-based farming.
The Aral Sea basin in Central Asia and the major rivers flowing through the region were once home to advanced river civilizations which used floodwater irrigation to farm.
Researchers reconstructed the effects of climate change on floodwater farming in the region and found that decreasing river flow was equally important for the abandonment of these previously flourishing city states.
Central Asia recovered quickly following Arab invasions in the 7th and 8th centuries CE because of favourable wet conditions.
But prolonged drought during and following the later Mongol destruction reduced the resilience of local population and prevented the re-establishment of large-scale irrigation-based agriculture.
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 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 abandonment of irrigation systems matches a phase of riverbed erosion between the 10th and 14th century CE, that coincided with a dry period with low river flows, rather than corresponding with the Mongol invasion.