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Central Asian river civilizations fell victim to climate change

Dec. 15, 2020 - LINCOLN, England

A new study challenges the long-held view that the destruction of Central Asia's medieval river civilizations was a direct result of the Mongol invasion in the early 13th century CE.

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.

The region's decline is often attributed to the devastating Mongol invasion of the early 13th century, but new research of long-term river dynamics and ancient irrigation networks shows the changing climate and dryer conditions may have been the real cause.

Researchers investigate an abandoned medieval canal, Otrar oasis, Kazakhstan. University of Lincoln

Research led by the University of Lincoln, UK, reconstructed the effects of climate change on floodwater farming in the region and found that decreasing river flow was equally, if not more, important for the abandonment of these previously flourishing city states.

Mark Macklin, author and Distinguished Professor of River Systems and Global Change, and Director of the Lincoln Centre for Water and Planetary Health at the University of Lincoln said: "Our research shows that it was climate change, not Genghis Khan, that was the ultimate cause for the demise of Central Asia's forgotten river civilizations.

"We found that 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.


Abstract: The Aral Sea basin in Central Asia and its major rivers, the Amu Darya and Syr Darya, were the center of advanced river civilizations, and a principal hub of the Silk Roads over a period of more than 2,000 y. The region’s decline has been traditionally attributed to the devastating Mongol invasion of the early-13th century CE. However, the role of changing hydroclimatic conditions on the development of these culturally influential potamic societies has not been the subject of modern geoarchaeological investigations. In this paper we report the findings of an interdisciplinary investigation of archaeological sites and associated irrigation canals of the Otrār oasis, a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage site located at the confluence of the Syr Darya and Arys rivers in southern Kazakhstan. This includes radiometric dating of irrigation canal abandonment and an investigation of Arys river channel dynamics. Major phases of fluvial aggradation, between the seventh and early ninth century CE and between 1350 and 1550 CE coincide with economic flourishing of the oasis, facilitated by wet climatic conditions and higher river flows that favored floodwater farming. Periods of abandonment of the irrigation network and cultural decline primarily correlate with fluvial entrenchment during periods of drought, instead of being related to destructive invasions. Therefore, it seems the great rivers of Central Asia were not just static “stage sets” for some of the turning points of world history, but in many instances, inadvertently or directly shaped the final outcomes and legacies of imperial ambitions in the region.


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The study of human activity through the recovery and analysis of material culture. Archaeologists study human prehistory and history, from the development of the first stone tools at Lomekwi in East Africa 3.3 million years ago up until recent decades.




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