How to optimize ecological compensation to alleviate environmental injustice in different cities in the Yellow River Basin? A case of integrating ecosystem service supply, demand and flow

Ecosystem services generated in a specific area have utility outside the area. Ecosystem services have obvious externality. The degree and scale of ecosystem services directly delivered to beneficiaries vary greatly among different regions, resulting in environmental injustice. Implementation of ecological compensation (EC) can internalize the external effects and effectively solve environmental justice problems. It is imperative to clarify the supply-transmission-benefit mechanism between the providers of ecological products and services and the beneficiaries, and scientifically determine the beneficiaries and the compensation amount. Based on externalities and environmental justice theories, this study used the InVEST model and hotspot analysis to quantitatively assess carbon sequestration (CS) supply and demand in the Yellow River Basin and identified ecosystem service supply and demand areas. The comparative ecological radiation force (CERF), based on the gravity model and the breaking-point formula, was proposed to reveal the transmission paths, ecosystem service flow and to quantify the amount of EC. The result showed that although there was a spatial mismatch between the supply and demand of CS in the Yellow River Basin, most of the regions showed a surplus pattern. Baotou, Aba, Bayannur, and Erdos were the regions with large CERFs, and the amount of CS transferred outward was large. The total amount of EC obtained from the ecosystem services demand area was about 67.6 billion RMB. This study can provide references for the Yellow River Basin ecosystem management and the formulation of EC policies.