Absorptive capacity and the low-carbon impact of external digital and green technologies

Digital and green technologies (DGTs) have emerged as critical drivers of the urban low-carbon transition. The extent to which cities can benefit from external DGTs depends heavily on their absorptive capacity (ACAP). However, previous studies have typically used R&D expenditures as a proxy and have focused on high-tech sectors in Western contexts, overlooking the multidimensional and interregional nature of ACAP in developing economies. To address this gap, this study proposes a novel multiplex network model that captures intercity flows of technology, capital, and skilled labor to measure both potential absorptive capacity (PACAP) and realized absorptive capacity (RACAP) across 223 Chinese cities. A moderating effect model is further employed to examine how ACAP influences the effects of external and local DGTs on carbon emission intensity. The results of the analysis reveal that RACAP displays stronger spatial polarization than PACAP does, with higher concentrations in core innovation cities and a weaker presence in peripheral regions. External and local DGTs demonstrate asymmetric impacts: external DGTs play a stronger role in driving low-carbon transitions, whereas the effects of local DGTs are less evident, possibly because of slower diffusion or absorptive constraints. Moreover, RACAP enhances the emission reduction effect of external DGTs, enabling cities to transform external technologies into tangible low-carbon outcomes. These results underscore the importance of strengthening RACAP, especially in less developed areas, to unlock the full potential of external DGTs for sustainable urban transitions.