Soil Erosion Under Climate and Land Use Changes in China: Incorporating Ecological Policy Constraints

Projections of soil erosion under climate and land use changes are pivotal for optimizing soil conservation strategies. Ecological policies are thought to influence future land-use changes and associated soil erosion dynamics. However, these policies are inadequately incorporated into projections, leaving the future trajectory of soil erosion still unclear. China's ecological redline policy (ERP) is among the first national policies to integrate multiple ecosystem services into land use planning, preventing anthropogenic soil erosion on over 25% of the territory. Therefore, focusing on China, three alternative Shared Socioeconomic Pathway and Representative Concentration Pathway scenarios (SSP1-2.6, SSP3-7.0, and SSP5-8.5) were coupled with future-oriented ERP to reflect future soil erosion patterns by the late-21st century. Projections rely on an integrated multi-model approach. The conducted analysis suggests that climate change is projected to exacerbate soil erosion by 12.06%-36.90% due to increased precipitation, characterized by high-intensity events. Land use change is projected to mitigate or even reverse the climate-induced increase in soil erosion. The combined climate and land use simulations showed that the annual average soil erosion rate will increase by 26.36% under the SSP5-8.5 scenario, while it will decrease by 8.08% and 14.94% under the SSP1-2.6 and SSP3-7.0 scenarios, respectively. The implementation of ERP reduces potential soil erosion by 4.08%-14.89% (equal to 0.31-0.86 Gt year-1 soil loss) in the late-21st century, particularly in scenarios with intensive conflicts between population and land sources. This study provides a valuable reference for the formulation of national strategies aimed at controlling soil loss accelerated by climate change.