Carbon Sinks and Green Efficiency: Evidence from Chinese Provincial Panel Data

Under China’s “dual carbon” strategy, carbon sinks—natural systems that absorb atmospheric CO₂—have become a key component of green development policy. This study uses provincial panel data from 2001 to 2021 and applies a Slack-Based Measure (SBM) model to estimate green economic efficiency. A two-way fixed effects regression is then used to assess the impact of carbon sink reserves on efficiency and explore potential mechanisms. Results show that: (1) carbon sinks significantly improve green economic efficiency, and this effect remains robust across lagged models, variable trimming, and alternative efficiency measures; (2) the positive effect is stronger in coal-intensive and less-developed regions, suggesting a compensatory ecological role; (3) mechanism analysis reveals that carbon sinks indirectly boost efficiency by promoting green technological innovation and encouraging industrial upgrading. This paper extends the existing literature by integrating ecological factors into the study of carbon efficiency and highlights the economic value of natural capital. Policy suggestions include improving carbon sink monitoring and trading systems, formulating region-specific ecological-industrial integration strategies, and enhancing incentives for low-carbon innovation.