The world’s earliest Aral-Sea type disaster: the decline of the Loulan Kingdom in the Tarim Basin

Abstract

Remnants of cities and farmlands in China’s hyperarid Tarim Basin indicate that environmental conditions were significantly wetter two millennia ago in a region which is barren desert today. Historical documents and age data of organic remains show that the Loulan Kingdom flourished during the Han Dynasty (206 BCE–220 CE) but was abandoned between its end and 645 CE. Previous archaeological, geomorphological and geological studies suggest that deteriorating climate conditions led to the abandonment of the ancient desert cities. Based on analyses of lake sediments from Lop Nur in the eastern Tarim Basin and a review of published records, we show that the Loulan Kingdom decline resulted from a man-made environmental disaster comparable to the recent Aral Sea crisis rather than from changing climate. Lop Nur and other lakes within the Han Dynasty realm experienced rapidly declining water levels or even desiccation whilst lakes in adjacent regions recorded rising levels and relatively wet conditions during the time of the Loulan Kingdom decline. Water withdrawal for irrigation farming in the middle reaches of rivers likely caused water shortage downstream and eventually the widespread deterioration of desert oases a long time before man initiated the Aral Sea disaster in the 1960s.

Climate Change and the Rise of the Central Asian Silk Roads

“…This change is associated with a shift towards wetter taxa in the pollen record (Rasmussen et al 2001). These changes are not reproduced in other records from the margin or outside of the region in which precipitation changes were simulated, including the Aral Sea (Ferronskii et al 2003;Huang et al 2011), Lake Karakul, Tajikistan (Mischke et al 2010), Lake Balikun (An et al 2011), Wulunga Lake (Jiang et al 2007), Lop Nur (Mischke et al 2017), Lake Karakuli (Aichner et al 2015), China or the Chinese Loess plateaux (Zhang et al 2013).…”

Irrigation-Induced Environmental Changes around the Aral Sea: An Integrated View from Multiple Satellite Observations

“…The opposite trends of precipitation in the Aral Sea in TRMM satellite retrievals (Figure 5b) to those in surface observations might come from the satellite precipitation retrieval algorithm, in which the surface albedo was fixed using the value of water surface rather than applying the dynamic surface albedo. This is a critical issue that needs to be solved in the future because: (1) over water bodies, satellite remote sensing is the only method to retrieve precipitation given that no in situ measurements exist at a regular time interval; and (2) several inland water bodies have dried up in the past [43] or are shrinking in recent years [8,44] due to either human activities or natural variability. Besides human-induced surface temperature changes in the Aral Sea, there were significant changes in AOD, precipitation, soil moisture, and NDVI in a larger domain in the ASB.…”

On the Paleo-climatic/Environmental Impacts and Socio-Cultural System Resilience along the Historical Silk Road

“…For instance, the eco-environment of the oasis systems in the southern part of the Tarim Basin has taken great changes during the recent 2000 years, which are characterized by the evolution and desertification of oasis and led to many famous ancient cities having been abandoned (Zu et al 2003;Liu et al 2016). However, research based on analyses of lake sediments from Lop Nur in the eastern Tarim Basin also shows that the Loulan Kingdom decline resulted from a man-made environmental disaster rather than from changing climate, because lakes in adjacent regions recorded rising levels and relatively wet conditions during the same period (Mischke et al 2017). Analyses on the distribution and evolution of oases show that environmental changes are partly due to the aridization of climate before the 20th century but mainly attributed to the human activities in the 20th century.…”