Source: Fullen & Mitchell 1994The figure above shows the distribution of sandy deserts (1-8) and lands (9-12) with respect to climatic zones in China. Sandy deserts and lands are differentiated as the latter is formed out of human activity. Historically many parts of China have been susceptible to desertification, all of them located in the north-west, north and north-east dryland area. The Mu Us sandy land (see figure) has existed throughout the Quaternary but its extent has fluctuated through time with moisture availability. More recently it has been subject to encroachment by a sandy desert since the Tang Dynasty (AD 618-906). There is evidence for widespread desertification in the semi-arid steppe dating back to the Han Dynasty (202 BC-AD 220). Historically the control of the aridity has been linked to the effect of the ITCZ on the East-Asia monsoon, and its failure has been linked to the collapse of the Tang dynasty.
Source: Yong Zha and Jay Gao (2000)
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