Accounting of provincial horizontal carbon eco-compensation standard under multiple participation scenarios.

As the world’s largest energy consumer and CO2 emitter, China faces severe sustainable development challenges and intense international pressures. The pronounced spatial heterogeneity of CO2 emissions and sinks creates a dynamic pattern of carbon-deficient and carbon-surplus regions. Horizontal carbon eco-compensation activates the market value of carbon sinks, redistributes sink-related benefits, and internalizes both positive and negative environmental externalities, thereby facilitating the valuation of carbon-sink ecosystem services. In this research, CO2 emission space is treated as a tradable ecological product. Within a government-led, market-coordinated accounting framework, carbon-deficient regions provide ecological compensation to carbon-surplus regions, while the latter are compensated for environmental stewardship and opportunity expenses. The CO2 emission quotas of each province are first determined by the entropy method, and a horizontal carbon ecological compensation recipient and payer identification framework is constructed. Next, the compensation standard accounting models under three scenarios of active participation, passive participation and refusal to participate are constructed respectively. Finally, the empirical analysis is carried out with 30 provinces in China as the object set. The results show that: (1) Regions with high CO2 emissions are mostly economically developed, energy-intensive or densely populated areas, while the regions with high CO2 sequestration often have the characteristics of complete ecological patterns, superior hydrothermal conditions or remarkable ecological restoration results. (2) Among the 30 provinces studied, 18 provinces show the characteristics of carbon surplus, which are mainly distributed in the south, central and western regions and parts of the north; the remaining 12 are carbon-deficient regions, concentrated in the eastern coastal and northern regions of China. (3) Under the framework of the provincial horizontal carbon eco-compensation mechanism, this research identifies three behavioral scenarios: active participation, passive participation and refusal to participate. It is found that active participation compensation is the optimal strategy, which provides a basis for the formulation of differentiated horizontal eco-compensation standards and implementation plans.