The 8.2 and 4.2 ka BP abrupt climate events, serving as the stratigraphic boundaries between the Early-Middle and Middle-Late Holocene, divide the Holocene into the Greenlandian, Northgrippian, and Meghalayan stages. These two events are widely considered closely associated with major historical transitions, including the decline of the Mesopotamian civilization and cultural shifts during the Chinese Neolithic period. Speleothem oxygen isotope ( δ ¹⁸O) records are ideal proxies for reconstructing the 8.2 and 4.2 ka BP climate events because they frequently show sub-annual to decadal temporal resolutions and have a long temporal coverage. However, due to the influence of local environment in individual cave records and the inherent uncertainties in stalagmite dating, the characteristics of these two events in the East Asian summer monsoon (EASM) region remains debated. What are their spatio-temporal patterns, and do different regions exhibit divergent responses? Investigating these questions provides important insights into the regional response mechanisms of Holocene abrupt climate events and offers valuable implications for understanding regional climate sensitivity in the context of ongoing global warming.
The recently published paper in Science China Earth Sciences , entitled “ Spatio-temporal characteristics of the 8.2 and 4.2 ka BP climate events in the East Asian summer monsoon region recorded by stalagmite δ 18 O data ”, was jointly authored by Dr. Beixi Fan from the Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences; Prof. Bao Yang from Nanjing University; Postdoctoral Researcher Feng Wang from the Institut National de la Recherche Scientifique (now at the University of Iowa); Prof. Fredrik Charpentier Ljungqvist from Stockholm University; and Prof. Achim Bräuning from Friedrich-Alexander-University Erlangen-Nürnberg. The researchers evaluated the 8.2 and 4.2 ka BP climate events in the EASM using 13 published stalagmite δ ¹⁸O chronologies. Through a comprehensive framework that combines Bincor correlation analysis (Binned correlation), Sensitivity experiments, and Monte Carlo empirical orthogonal function (MCEOF) decomposition, this study systematically resolves the issues of irregular sampling intervals and differing time points in stalagmite records comparisons, evaluates the influence of different geographical locations and temporal resolutions on the detection of abrupt climate events, and fully considers the age uncertainties inherent in stalagmite δ ¹⁸O dating. By integrating multiple stalagmite records, it not only overcomes the limited representativeness of individual cave archives but also reveals the detailed processes of abrupt climate shifts at the regional scale. It further reconstructs the spatio-temporal patterns of the 8.2 and 4.2 ka BP events, providing new evidence and methodological insights for understanding Holocene climate events in the EASM region.
The results show that high-resolution stalagmite δ 18 O sequences from nearby locations exhibit strong consistency during the Holocene, thus capturing regional climate patterns (Fig. 1). However, both temporal resolution and geographical location significantly affect the ability of the stalagmite δ 18 O sequences to capture the onset and termination of abrupt events. The results support the existence of a regional consistency in the 8.2 ka BP event across the EASM region, lasting ~150 years from 8.23 to 8.08 ka BP. In contrast, the δ ¹⁸O signals for the 4.2 ka BP (~4.26–3.97 ka BP) event reveal significant north–south differences, suggesting large spatial heterogeneity across the EASM region. Future studies should employ more intensive proxy networks and multi-index analysis of the same stalagmite material and apply representative chronological markers to precisely reconstruct the spatio-temporal evolution of abrupt climate events and improve the understanding of their underlying mechanisms.
This study was supported by the National Program on Key Basic Research Project of China (Grant No. 2022YFF0801102), the National Natural Science Foundation of China (Grant No. 42130511), the Swedish Research Council (Vetenskapsrådet, Grant No. 2023-00605), the Marianne and Marcus Wallenberg Foundation (Grant No. MMW 2022-0114), and the Centre for Advanced Study (CAS) at the Norwegian Academy of Science and Letters(2024/2025yr).
See the article:
Fan B, Yang B, Wang F, Ljungqvist F C, Bräuning A. 2025. Spatio-temporal characteristics of the 8.2 and 4.2 ka BP climate events in the East Asian summer monsoon region recorded by stalagmite δ 18 O data. Science China Earth Sciences , 68(9): 2839–2852, https://doi.org/10.1007/s11430-025-1621-5
Science China Earth Sciences