Hub, Bridge, or Channel? Role Selection and Evolution of Urban Green Innovation Networks Under Climate Risk

Physical climate risks are reshaping economic geography and pose a direct threat to the collaborative networks of green innovation that underpin mitigation and adaptation. This paper examines how climate risk differentially affects three core structural roles that cities occupy in green innovation collaboration networks: hubs, which aggregate knowledge and are measured by degree centrality; channels, which transmit information and are captured by closeness centrality; and bridges, which link resources and are reflected in betweenness centrality. Using a panel of Chinese cities over the past decade and two way fixed effects models, we estimate the impacts of climate risk on cities’ network roles. The results show that climate risk significantly reduces all three roles, but the negative effects on channels and hubs are substantially larger than the effect on bridges. This pattern is consistent with a defensive structural reconfiguration of the network that emphasizes resilience at the expense of efficiency. The specific pathways and magnitudes of change depend on local financial conditions, regulatory responses, a city’s position in the urban hierarchy, and the type of climate risk encountered. These findings incorporate exogenous environmental pressure into theories of network evolution and provide empirical support for shifting regional innovation policy from an efficiency first orientation toward a resilience oriented innovation ecosystem.