Annually laminated stalagmite inferred variations of precipitation and temperature in northern China over the last 150 years

Speleothem-based multiproxy records are essential for deciphering the evolution of the East Asian summer monsoon (EASM) and its response to global warming. Here we present multiple proxy records of an annually laminated stalagmite (LF36) collected from Longfeng Cave, Shanxi Province, northern China, to study hydroclimatic and environmental changes, which has been constrained by ²³⁰Th dating and lamina counting and spans the period of 1869–2018 AD. The high-resolution δ¹⁸O record and its comparison with other regional records suggest that the variation of regional precipitation δ¹⁸O is controlled by changes in the EASM intensity and exhibits a significant multi-decadal periodicity, consistent with the proxy-based EASM precipitation records from northern China over the last 150 years. The dominant variabilities of ~ 20–30 years and 50–70 years agree well with changes in the Pacific Decadal Oscillation (PDO), suggesting that these decadal oscillations are likely linked to the PDO variation. However, the stalagmite δ¹³C record shows increased variability since 1940 AD, coinciding with the annual lamina thickness and resembling temperature changes over the last 150 years. The coincidence between stalagmite δ¹³C and annual lamina thickness suggests that temperature, particularly summer temperature, has influenced stalagmite δ¹³C and annual lamina thickness through the linkage between temperature and soil respiration and CO₂ concentration. In addition, the δ¹³C record shows a gradual depleting trend since the beginning of 1869 AD, which likely affirms the association with an increase in the global temperature, CO₂ concentration, and δ¹³C depletion of atmospheric CO₂.