Uneven efficiency, uneven policy: Regional disparities in China's low-carbon transition through a green public economics lens

China's fossil fuel-driven economic expansion has intensified environmental pressures, particularly in terms of CO 2 emissions. As the world's largest emitter and a key participant in the Paris Agreement, China's progress in energy efficiency is critical to global climate objectives. This study employs a DEA (Data Envelopment Analysis)-the Banker, Charnes and Cooper model that incorporates CO 2 as an undesirable output to assess energy efficiency and carbon emissions across 30 Chinese provinces from 2008 to 2020, and applies a Bootstrap correction to address bias and variability in efficiency scores. The results reveal discernible variation in energy efficiency across provinces. Five provinces, namely Hebei, Gansu, Guizhou, Shanxi, and Yunnan, consistently exhibit efficiency values below 0.5, while four provinces, namely Beijing, Guangdong, Hainan, and Jiangsu, consistently achieve efficiency values of 1.0. At the regional level, the eastern region has an average efficiency of 0.873, which is higher than the national average of 0.690, whereas the central region (0.577) and western region (0.607) show declining trends. After Bootstrap correction, the national average efficiency decreases from 0.690 to 0.562, suggesting that the initial estimates may be overestimated. These findings highlight the unevenness in energy efficiency and the potential need for regionally differentiated policies, providing support for targeted policy interventions from a green public economics perspective to enhance energy governance and reduce emissions. Efficiency disparities may partly reflect technology gaps. Accordingly, green financial transfers should be complemented by technology diffusion and capacity building in less developed regions. However, given the bootstrap uncertainty, these implications should be drawn with caution and require further empirical support.