Holocene 500-Year Periodic Demographic Fluctuations Linked to Climate Change in Southwest China Mountains

Prehistoric demographic dynamics were likely influenced by multi-centennial-scale climate oscillations during the Holocene. However, the relationship between cyclic climate change, human demography and subsistence strategies in Southwest China remains unclear owing to the lack of high-resolution proxies for population reconstruction. This study compiles 885 archaeological radiocarbon dates from Southwest China to reconstruct long-term population histories using summed probability distributions. In general, the dramatic rise in population began around 6200 cal BP in Southwest China, coinciding with the mild-Holocene optimum that provided abundant natural resources for foraging populations. Subsequently, it accelerated around 5300 cal BP with the introduction of millet farming and maintained a high population size between 5000 and 2500 cal BP. Notably, a dominant ~500-year (yr) cycle in human population dynamics across the Holocene was identified. In particular, the five most striking peaks at ca. 4870, 4430, 3950, 3290 and 2755 cal BP, within the interval of 5000–2500 cal BP, correspond closely to warm–humid monsoon phases and the flourishing of millet and rice mixed agriculture. Synchronous ~500-yr cyclic changes in climate and demography suggest that warm–humid conditions are favourable for agricultural productivity, supporting the boom in population size and flourishing of prehistoric cultures.