Groundwater sapping as the cause of irreversible desertification of Hunshandake Sandy Lands, Inner Mongolia, northern China

In the middle-to-late Holocene, Earth’s monsoonal regions experienced catastrophic precipitation decreases that produced green to desert state shifts. Resulting hydrologic regime change negatively impacted water availability and Neolithic cultures. Whereas mid-Holocene drying is commonly attributed...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2015-01, Vol.112 (3), p.702-706
Main Authors: Yang, Xiaoping, Scuderi, Louis A., Wang, Xulong, Scuderi, Louis J., Zhang, Deguo, Li, Hongwei, Forman, Steven, Xu, Qinghai, Wang, Ruichang, Huang, Weiwen, Yang, Shixia
Format: Article
Language:English
Subjects:
Desertification
Geological time
Geomorphology
Groundwater flow
Hydrology
Physical Sciences
Precipitation
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Summary:In the middle-to-late Holocene, Earth’s monsoonal regions experienced catastrophic precipitation decreases that produced green to desert state shifts. Resulting hydrologic regime change negatively impacted water availability and Neolithic cultures. Whereas mid-Holocene drying is commonly attributed to slow insolation reduction and subsequent nonlinear vegetation–atmosphere feedbacks that produce threshold conditions, evidence of trigger events initiating state switching has remained elusive. Here we document a threshold event ca. 4,200 years ago in the Hunshandake Sandy Lands of Inner Mongolia, northern China, associated with groundwater capture by the Xilamulun River. This process initiated a sudden and irreversible region-wide hydrologic event that exacerbated the desertification of the Hunshandake, resulting in post-Humid Period mass migration of northern China’s Neolithic cultures. The Hunshandake remains arid and is unlikely, even with massive rehabilitation efforts, to revert back to green conditions. Significance In contrast to earlier assertions that deserts in northern China are 10 ⁶ years old, our multidisciplinary investigation in the Hunshandake Sandy Lands, located in the eastern portion of China’s desert belt, shows that this desert is ca. 4,000 years old. This study documents dramatic environmental and landscape changes in this desert during the last 10,000 years. For the first time to our knowledge we present a case of desertification mainly triggered by changes in the hydrological and geomorphological system, associated with climate change at ca. 4.2 ka. Our research on the human–environment interactions in the Hunshandake suggests Chinese civilization may be rooted in the marginal areas in the north, rather than in the middle reaches of the Yellow River.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1418090112