Impacts of heterogenous technological innovations on green productivity: An empirical study from 261 cities in China

As the world second largest economy, China aims at achieving high-quality and innovation-driven development. This paper investigates the effects of different technological innovations on green productivity in 261 Chinese cities from 2004 to 2017. We employ the super-efficiency Epsilon-based measure (EBM) model with undesirable outputs under meta frontier and a global Malmquist-Luenberger (GML) index. We decompose the GML index into efficiency change (GEC) index and technology change (GTC) index to measure the dynamic changes of China's urban green development. Results showed that the average GML index is 0.924 thereby, indicating China's urban green development is at a decreasing trend. The eastern region had the highest GML index among three regions followed by the western region. Moreover, we explored the determinants of urban green productivity through panel quantile regression and found the heterogeneous impacts of different technological innovations on green productivity. Invention patents and design patents positively affected the urban green productivity while utility patents exerted a significantly negative influence. Invention patents promoted the GTC and GEC index while utility patents impeded at some quantiles. FDI yielded both “Pollution Halo Hypothesis” and “Pollution Heaven Hypothesis” effects. Invention, utility and design patents all have threshold effects on China's green productivity.