Warfare impact overtakes climate-controlled fires in the eastern Silk Roads since 2000 BP

Warfare has played an important role in fire regimes; however, it remains unclear whether and when it may have impacted fire history along the Silk Roads. Based on a high-resolution record of black carbon in alpine-lake sediment, and warfare data from historical documents, we explore the relationships between fire, fuel, climate, and human activity along the eastern Silk Roads over the past 6,000 years. Results show that fire activities were low in the middle Holocene but gradually increased in the late Holocene, a pattern closely related to the intensification of drought and the expansion of herbaceous vegetation. However, the intensity and amplitude of paleo-fires increased significantly in the past 2,000 years, a pattern that was no longer synchronized with climate and vegetation changes on centennial timescales; rather, the sequence demonstrated a significant positive correlation with the documented number of wars in different dynasties. We argue that warfare between different political powers may have been the primary influence on the occurrence of five high-intensity fires since 2000 B.P. on centennial timescales in the eastern Silk Roads. Our study certainly reveals the impact of warfare activities related to dynastic change on fire regimes in Chinese history, providing a novel perspective for understanding the impact of human activities on the environment.