The Carbon Emission Reduction Effect of the Digital Economy: Mechanism Reconstruction Based on the Suppression Effect—A Case Study of the Pearl River Delta Urban Agglomeration

With the continuous expansion of the digital economy, its share in China’s overall economy has been steadily increasing. Against the backdrop of the national “dual-carbon” goals, an important question arises: how does the digital economy contribute to carbon reduction? This study selects panel data from nine cities in the Pearl River Delta (PRD) urban agglomeration between 2011 and 2023. The development level of the digital economy is measured using the entropy weight method and an index system. A two-way fixed effects model and a mediation effect model are then employed to empirically examine the relationship and mechanisms between the digital economy and urban carbon emissions. The main findings are as follows: (1) the development of the digital economy exerts a significant negative regulatory effect on carbon emissions, which remains robust after a series of tests; (2) heterogeneity analysis reveals that the inhibitory effect of the digital economy on carbon emissions is more evident in economically advanced cities, and the development level of metropolitan areas significantly influences this relationship; (3) mechanism analysis indicates that stronger environmental regulation significantly enhances the carbon reduction effect of the digital economy; and (4) the scale of e-commerce in the PRD plays a “suppression effect”, offsetting the original carbon-increasing effect of the digital economy and emerging as the key factor underlying its net carbon-reducing impact. Based on these results, the paper provides policy recommendations to better leverage the digital economy in supporting regional carbon reduction.