Remarkable signals of the ancient Chinese civilization since the Early Bronze Age in the marine environment

The signals of fire activity induced from climate and ancient human activities could be recorded in sedimentary strata. We examined a 6000-year black‑carbon (BC) record—including char and soot—of a sediment core from the South Yellow Sea. The climate change had a threshold effect on the fire regime, and dominated the char emissions. The soot/BC signals depicted that the anthropogenic emissions related to the evolution of the Chinese civilization since the Early Bronze Age (~4 ka) have overwhelmed natural soot emissions. The soot variation in the record closely matched periods when there was large-scale use of coal or charcoal after the Han Dynasty and when indigenous coking technology was promoted after the Tang Dynasty; low soot-abundance in the record coincided with periods of social unrest. This work illustrates how soot signals can be a robust tracer of civilization evolution.