Asynchronous modes of paleofire occurrence in eastern monsoonal China since the LGM

Wildfire is a key environmental influence on ecosystems, global and regional climates, and human societies. Reconstructing past fire histories and investigating the relationships between wildfires, vegetation, and climate are crucial for understanding the long-term patterns of fire regimes and predicting future wildfire risks. Although there has been considerable research on local fire events, consideration of regional-scale fire over extended timescales is not well covered in China. In this study, we synthesized 70 proxy records of past fire, including charcoal and black carbon, from eastern monsoonal China, since the Last Glacial Maximum (LGM, 21–18 ka BP) to investigate the spatiotemporal patterns in fire history. Our results reveal an asynchronous pattern in fire activity between southern and northern China. In southern China, higher fire activity occurred during the LGM, Younger Dryas (12.8–11.6 ka BP) event and early Holocene (11–7 ka BP), corresponding to periods of drier climate, and suggesting that fire regimes were enhanced by lower precipitation there. In contrast, fire activity in northern China increased during the Bølling-Allerød (B/A, 14.8–12.9 ka BP) warming and the mid-Holocene, with peak activity associated with wetter periods that probably promoted plant growth, highlighting the role of biomass as fuels for fire events. Regional fires might be attributed to precipitation control modulated by regulating the combustibility and availability of fuels. Furthermore, El Niño–Southern Oscillation (ENSO) variability creates episodes of drought and rain by increasing or decreasing the intensity of the East Asian Summer Monsoon (EASM), and is therefore likely linked to wildfire dynamics.