New quantified climate reconstruction in southern China suggests a potential influence of winter cloud cover across East Asia during the Holocene

Previous studies have advanced our understanding of paleoclimate features and dynamics in East Asia, particularly within the East Asian monsoon domain (EAMD) since the last glacial period. However, a lack of quantitative reconstructions in the boundary area between tropical and subtropical zones has largely hindered our spatial comprehension of the relationship between precipitation and temperature throughout the EAMD. In this study, we present a continuous pollen record from the Pearl River delta over the past 13.2 ka and a quantitative climate reconstruction using an updated modern pollen dataset. The findings indicate that from 13.2 ka to 9.9 ka, the study area was encompassed by mid-montane moist evergreen broadleaved forest (EBLF), transitioning to semi-humid EBLF or lowland monsoon EBLF during the late Holocene. Anthropochory plants have emerged as dominant taxa by about 1.9 ka, indicating a large-scale impact of human activities. The results of quantitative climate reconstruction indicate that the range of annual precipitation varies by ca. 80–120 mm, and the changing pattern is consistent with the traditional ‘Holocene thermal maximum’ mode, with summer solar radiation potentially being the primary controlling factor. The range of annual temperature variability fall between 19.5 °C and 22.5 °C, exhibiting a warming trend likely influenced by changes in Northern Hemisphere ice volume. There is a phase difference of about 2–4 ka between the peak values of precipitation and temperature. The variation patterns of change across eastern Asia exhibit distinct differences when compared to the proxy records in the EAMD. It appears that such asynchrony between precipitation and temperature is more pronounced in southern China. In comparison with model simulations, it is believed that spatiotemporal variation in winter cloud cover may play a crucial role in explaining this phenomenon of regional heterogeneity.