Sedimentary black carbon reveals shifting anthropogenic drivers in Lake Erhai Basin, southwest China

Human activities have profoundly transformed Earth's surface systems, becoming the dominant force driving global environmental change. Black carbon (BC) in lake sediments serves as an effective tracer of anthropogenic influence, enabling the identification and quantification of human impacts on ecosystems. In this study, we present a BC record from Lake Erhai in southwest China to explore its linkages to climatic variability and anthropogenic pressures. The results reveal that char constitutes over 95 % of the sedimentary BC, implicating lower-temperature combustion as the primary source. Between 1555 and 1950 CE, BC deposition fluxes remained low, fluctuating with natural background of 0.7 g/m²/yr. However, the post-1950 rapid population growth and industrial expansion triggered a marked increase in BC emissions, with deposition fluxes surging sharply to the maximum of 5.3 g/m²/yr. This shift underscores the sensitivity of sedimentary BC as an indicator of human activity in the Lake Erhai Basin. Comparative analysis with BC records from other Chinese lakes demonstrates a consistent, century-long rise in deposition fluxes across regions with char persistently dominating the BC composition. These findings provide new insights into human influence during the Great Acceleration. Furthermore, integrating management of biomass and coal combustion and promoting cleaner energy transitions would be critical to mitigating the negative climate-environmental impacts of BC, especially under warming and drying trends.