Climate transition over the past two centuries revealed by lake Ebinur in Xinjiang, northwest China

Abstract

Global climate has undergone dramatic changes over the past 200 years, accurately identifying the climate transition (from LIA to 20th century warming) and its controlling factors will help to address the risks posed by global warming. Detailed analyses of chronology, grain size, color reflectance (L*, a*) and carbon content (TOC, TIC) were conducted on a 200-year sedimentary record from lake Ebinur in Xinjiang, northwest China. The results show that lake sediments are mainly transported by wind, and there are two kinds of different sources and transport processes. Comparative analysis of multi-proxies reveals that the climate transition took place in 1920 AD. In the early period (1816–1920 AD), the high C values indicate strong transport dynamics; the high proportion of ultrafine component indicates strong pedogenesis, combined with high TOC and a* values, it is inferred that the climate is cold and wet. In the later period (1920–2019 AD), the proxies show opposite changes, which may reveal a warm and dry climate. Based on a comprehensive analysis of multi-drivers, we propose that the increase of solar irradiance played a dominant role in 1920 AD climate transition, and the gradual rise in the concentrations of greenhouse gases may have a positive feedback effect.