Does a carbon emissions trading scheme spur urban green innovation? Evidence from a quasi-natural experiment in China

Based on the panel data of 277 cities between 2003 and 2017 and a unique city-level dataset of green patent applications, this study employs the difference-in-differences (DID) method to evaluate the effect of China's carbon emission trading scheme (ETS) pilots on urban green innovation. The findings indicate that China's ETS pilots have a positive impact on urban green innovation, and that impact is more significant for municipalities than for prefecture-level cities. Furthermore, the impact on different categories of urban green innovation is heterogeneous. More specifically, China's ETS pilots have significantly spurred urban green innovation that is closely related to energy conservation and emission reduction, including alternative energy production, transportation, energy conservation and so forth. Moreover, the facilitating effect of China's ETS pilots on urban green innovation suffers from a lagging effect, which began to show a significant positive effect in 2016. Overall, this paper identifies the effect of China's ETS pilots on urban green innovation, and suggests that the government should consider the heterogeneity of urban green innovation when designing national ETS policies.