Multi-decadal to centennial scales variability in the East Asian Summer Monsoon around the 5.5 kyr B.P. climate event

Understanding the variability of the mid-Holocene climate on multi-decadal to centennial scales, including the well-known 5.5 kyr B.P. cold event, is important to better evaluate possible changes of the East Asian Summer Monsoon (EASM) as global warming progresses. Over the past few decades, stalagmite oxygen isotope records have been widely used as a proxy for the EASM; however, most high-resolution stalagmite records are from southern China. In this study, a 4-yr-resolution δ18O record obtained from stalagmite TW704 in northeastern China was used to reconstruct regional precipitation and the EASM between 5.82 and 4.77 kyr B.P. (where B.P. indicates “before 1950 A.D.”). In general, the inferred EASM variations agree with previously published stalagmite records from southwestern and central China, suggesting synchronous variations of the EASM on decadal to centennial scales across monsoonal China. Our new record also features relatively large decadal–centennial EASM oscillations from northern China, with two centennial-scale weak EASM events centred at 5.6 and 5.0 kyr B.P. The former corresponds to the well-known 5.5 kyr B.P. cold event that occurred in the high-latitude North Atlantic Ocean. These depressed EASM events were probably caused by prolonged periods of El Niño, resulting in decreased precipitation over northeastern China. Our study provides robust evidence to support the hypothesis that ENSO played an important role in modulating the EASM during the mid-Holocene.