Introduction Under the double pressure of climate change and rapid urbanization, the degradation of the urban thermal environment has become a major obstacle to regional sustainable development. As a manufacturing-leading metropolis, Dongguan has undergone a drastic land use transformation and ecological space compression since 2000, potentially undermining its urban cooling system. Methods In this study, multi-temporal Landsat imagery was used to characterize the spatiotemporal evolution of land surface temperature (LST) and to examine the long-term dynamics of an urban cold island network from a source–corridor–matrix perspective. Cold island sources were identified using morphological spatial pattern analysis (MSPA), resistance surfaces were weighted using the CRITIC method, and potential cooling corridors were extracted using the minimum cumulative resistance (MCR) model. Results The results show that from 2000 to 2025, LST increased markedly and the urban heat island expanded from fragmented hotspots to a more continuous pattern, forming multi-core high-temperature clusters along major urban corridors and industrial belts. Meanwhile, core cold sources progressively contracted and became increasingly concentrated, with remaining major cold sources retreating to the southern hilly areas and the western waterfront. The thermal resistance surface shifted from a dispersed low-resistance structure to a more connected high-resistance pattern. Correspondingly, the cold island corridor network simplified from a multi-level configuration to a more linear framework, indicating a degradation sequence characterized by core source degradation–corridor fragmentation–functional decline. Discussion These findings highlight that blue–green space fragmentation and the intensification of high-resistance surfaces are key factors associated with the weakening of urban cooling connectivity. Rebuilding low-resistance ventilation corridors and strengthening ecological links among cold sources, supported by nature-based solutions, are critical for restoring cooling network functions and enhancing urban climate resilience.
Wang et al. (Tue,) studied this question.