Abrupt hydroclimatic changes in southern China during the transition from the Little Ice Age to Current Warm Period

Abstract

The variations in Indian summer monsoon (ISM) precipitation during the last millennium are key to understanding ISM dynamics and predicting extreme hydroclimatic changes under global warming scenarios. Here, we reconstructed the history of ISM precipitation during the past ca. 800 yr based on multiple proxies, including sediment grain size, organic matter content, biogenic silica content, magnetic susceptibility, and major element data (e.g., Fe, Ti, and Ca), obtained for a core from Lake Mahu in southwestern China. Relatively humid climate conditions prevailed during the Little Ice Age (LIA; 1400–1700 CE), whereas a relatively dry climate has characterized the Current Warm Period (CWP; 1800 CE–present). A significant dry event occurred during the transition from the LIA to CWP. The hydroclimatic record for the last millennium from Lake Mahu is generally similar to those of other areas affected by the ISM, including southwestern China, South China, the South China Sea, and northern India. We propose that southward migration of the Intertropical Convergence Zone may have been responsible for the abrupt hydroclimatic change during the transition from the LIA to CWP. • Humid LIA and dry CWP climates occurred in southern China and adjacent areas. • A notably drying event occurred during the LIA-CWP transition in southern China. • A rapidly southward shifted ITCZ may be responsible for such a hydroclimatic shift.