Quantifying Soil Erosion-Induced Lateral Carbon Loss in the East China Coast

Soil erosion profoundly impacts the lateral transport of soil organic carbon (SOC) from land to ocean. However, previous research has mainly focused on specific sites characterized by SOC loss through field measurements, leaving a gap in constructing the long-term estimates of lateral redistribution of SOC. In this study, we establish a centennial soil erosion and lateral SOC transport (CEST) framework to explore the magnitude and spatial heterogeneity of SOC loss in the East China Coast (ECC). By utilizing machine-learning approaches and the Revised Universal Soil Loss Equation model in conjunction with measured and satellite-derived data and CMIP6 data, the CEST framework allows for investigating SOC erosion distribution from 1980 to 2100. The results show that during the baseline period (1980–2020), the average potential SOC erosion rate in the surface soil (0–20 cm) was 0.122 t C ha⁻¹ yr⁻¹, which was higher than the overall average in China, and led to an annual redistribution of 13.85 Tg C of SOC. During the future period, by the year 2100, the SOC erosion will decrease by 1.61 Tg yr⁻¹ under the SSP119 scenario, while it will increase by 6.74 Tg yr⁻¹ under the SSP585 scenario. The total SOC erosion is mainly located in areas with an altitude of 300–1500 m, a slope range of 10°–15°, and low vegetation cover (NDVI < 0.6). Besides, vegetation plays a central role in slowing down SOC erosion, offsetting the contribution from precipitation increase.