Journal of Geographical Sciences ›› 2021, Vol. 31 ›› Issue (6): 765-784.doi: 10.1007/s11442-021-1870-8

• Research Articles •     Next Articles

Paleoclimatic proxies from global closed basins and the possible beginning of Anthropocene

LI Yu(), HAN Qin, HAO Lu, ZHANG Xinzhong, CHEN Dawei, ZHANG Yuxin, XU Lingmei, YE Wangting, PENG Simin, LI Yichan, FENG Zhuowen, LIU Hebin   

  1. Key Laboratory of Western China’s Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Center for Hydrologic Cycle and Water Resources in Arid Region, Lanzhou University, Lanzhou 730000, China
  • Received:2020-06-17 Accepted:2020-09-08 Published:2021-08-25
  • About author:Li Yu (1981-), Professor, specialized in paleoclimatic change. E-mail: liyu@lzu.edu.cn
  • Supported by:
    The National Key Research and Development Program of China(2019YFC0507401);National Natural Science Foundation of China(42077415);National Natural Science Foundation of China(41822708);The Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0202);The Strategic Priority Research Program of Chinese Academy of Sciences(XDA20100102)

Abstract:

Global closed basins, occupying almost one fifth of the world’s land area, spatially coincide with arid and semiarid areas. Paleoclimatic proxies can indicate basin-wide environmental change and human activity. However, previous studies have not approached the use of proxies in the same way to reconstruct natural and anthropogenic processes at regional and global scales. Here we present a regional study to investigate the basic processes of paleoclimatic proxies, from a typical closed-basin system in arid China. We use multiple paleoclimatic proxies of surface samples and sediments, as well as groundwater and sediment ages to study environmental change and human activity. We then establish a dataset for paleoclimatic proxies from global closed basins and do a numerical analysis on it. Regional studies verify that human activity greatly impacts paleoclimatic proxies, especially with regard to surface samples, as well as groundwater age, but Holocene sediments are less affected. Results from global studies indicate that the major changing trend of the wet/dry status of closed basins is associated with the movement of the westerly jet streams controlled by long-term changes in winter insolation. There is an abrupt change between 1800 AD and 1900 AD, according to a numerical synthesis of paleoclimatic proxies from global closed basins, which can be linked to human impact. We suggest this time period can be considered as a start point for the Anthropocene based on the sedimentary evidence of closed basins, globally.

Key words: Anthropocene, closed basins, paleoclimatic proxies, westerly jet streams, Asian summer monsoon, climate change