Regional differences and convergence of green innovation efficiency in China

Green innovation facilitates high-quality economic development and ecological environmental protection. Herein, the minimum distance to strong efficient frontier (MinDS) model was used to measure green innovation efficiencies (GIEs) of 30 Chinese provinces over a period of 21 years (2000–2020). Gini coefficient decomposition and kernel density estimation methods were used to analyze the regional differences of GIE. Spatial correlation was estimated to analyze spatial-spillover effects and spatial convergence of the GIE. China's GIE has shown an increasing trend with significant spatial differences in GIE among provinces. Regional differences and transvariation intensity are the primary sources of spatial differences in GIE. Regional differences in GIE have decreased, except for eastern regions. The results of spatial convergence estimation suggest spatial absolute and conditional convergence in all regions. Therefore, for the GIE improvement in China, the effects of economic level, industrial structure, and environmental regulations must be considered.