Late-Holocene hydroclimatic change and its effect on human activity at Xiada Co on the western Tibetan Plateau

Abstract

The scarcity of paleoclimate records in the western Tibetan Plateau (TP) hinders our understanding of how environmental evolution affects past human population, agriculture, and animal husbandry. Here, we utilized a range of materials to investigate the impact of climate change on human activities in the Xiada Co basin on the western TP during the Late-Holocene. We presented a continuous compound-specific hydrogen isotope record of sedimentary leaf waxes (δ2Hwax) from a sediment core of Xiada Co, and compared it to XRF core-scanning elements, brGDGT-based mean annual air temperature (MAAT) record, and fecal stanol-based human population proxy record from the same sediment core, as well as archeological evidence from the TP. The δ2Hwax exhibited a sustained increasing trend during the period from 4700 to 900 cal yr BP, followed by a generalized decrease in δ2Hwax values during 900–0 cal yr BP. The multi-proxy analysis of Xiada Co sediments revealed that the δ2Hwax values mainly reflect changes in the ISM precipitation, and are also influenced to some extent by glacier meltwater. Furthermore, a warm and humid climate condition was conducive to human habitation. Appropriate adaptation strategies, such as the herding of cold-tolerant and dry-tolerant sheep and the cultivation of barley in the western TP, led to a surge in population density during 3400–2900 cal yr BP, despite the slightly deteriorated climate background. This study confirmed the importance of choosing the right adaptive strategies to cope with climate change for human survival and development on the Tibetan Plateau.