Abstract Against the backdrop of intensified global climate change, countries are facing enormous pressure to reduce emissions while pursuing high-quality economic development. The digital economy is considered to have the potential to reduce carbon emissions. However, existing research mostly focuses on the impact of the digital economy on economic growth and industrial structure, with relatively insufficient research on its environmental impact, especially in terms of carbon emission efficiency. Therefore, based on panel data from 259 prefecture level and above cities in China from 2015 to 2022, this study innovatively constructed a comprehensive evaluation framework using spatial econometric models. Firstly, by constructing a spatial weight matrix, the spatial dependencies between cities could be obtained. Secondly, utilizing the spatial Durbin model ensured that the model could capture the impact of interactions between cities. In addition, to investigate the potential impact mechanism of the digital economy on carbon emission efficiency, this study used the mediation effect test method to systematically analyze the indirect impact of the digital economy promoting technological advancement and optimizing industrial structure on carbon emission efficiency. The results indicated that the digital economy substantially raised carbon emission efficiency, with a 0.017% increase in carbon emission efficiency for every 1% increase. The optimization of industrial structure is the core intermediary path for the digital economy to improve carbon emission efficiency, with a mediating effect of up to 0.490. In contrast, the direct mediating effect of green technology innovation is very weak (0.002) and not statistically significant. This difference suggests that the digital economy may mainly drive carbon efficiency improvement at the current stage by reshaping the macro industrial structure rather than directly stimulating green technology innovation at the enterprise level. In addition, the spatial spillover effect was significant, with a 1% rise in carbon emission efficiency in neighboring cities and a 0.065% increase in target cities. From 2015 to 2022, Moran's I value rose from 0.055 to 0.152, spatial clustering strengthened, Gearys C value decreased from 0.932 to 0.811, and spatial heterogeneity weakened. The study revealed the mechanism by which technological innovation and industrial structure optimization enhanced carbon emission efficiency, providing a new perspective for the regional coordinated development of the digital economy from the perspective of spatial spillover effects. Graphical Abstract
Gengquan Zhang (Sat,) studied this question.