Spatial Effects and Mechanisms of the Digital Economy and Industrial Structure on Urban Carbon Emissions: Evidence from 274 Chinese Cities

As China advances toward its “Dual Carbon” goals, clarifying the role of the digital economy (DE) in reducing urban carbon emissions is of growing importance. This study uses panel data from 274 Chinese prefecture-level cities (2011–2022) and applies benchmark regression, the Spatial Durbin Model (SDM), two-regime SDM, threshold analysis, and mediation effect modeling to examine the impact of the DE on carbon emission intensity (CEI) and its spatial spillover effects. Results show that the DE significantly reduces CEI through both direct and indirect channels. Spatial analysis reveals that the DE’s spillover effect is most pronounced within a 500 km range. Regionally, the DE has a stronger inhibitory effect on CEI in eastern and western regions, while its effect in the central region is weaker or even reversed, likely due to reliance on carbon-intensive industries. Resource-based cities exhibit stronger spatial spillovers than non-resource-based ones, suggesting greater potential for DE-driven low-carbon transitions. A threshold effect is also identified at a DE index value of 0.0326, beyond which the marginal benefits decline. Pathway analysis indicates that while the DE improves production efficiency, it does not significantly promote green, high-value-added transformation, partially masking its carbon reduction effects. These findings highlight the need for tailored regional strategies to enhance the low-carbon potential of the DE.