Green Borrowed Size: A Crucial Mechanism to Promote Green Innovation in Peripheral Cities

This study confronts the governance challenge of persistent green innovation disparities between core and peripheral cities, which impede the sustainable development of urban agglomerations. It introduces and empirically validates the concept of green borrowed size, defined as peripheral cities borrowing the agglomeration advantages of core cities in green innovation resources to compensate for endogenous innovation deficiencies, thereby fostering green innovation collaboration networks within urban agglomerations. Analysis of 14 Chinese urban agglomerations demonstrates that green borrowed size serves as a crucial mechanism for promoting green innovation in peripheral cities, primarily by amplifying the spillover effects originating from core cities. The effectiveness of this mechanism, however, is constrained by the inherent knowledge absorption capacity of peripheral cities and is significantly stronger within polycentric urban agglomerations. This repositions peripheral cities from passive spillover recipients to active co‐creators in regional green innovation ecosystems, offering a novel pathway to resolve core‐periphery disparities in urban agglomerations.