Reconceptualizing urban heat island: Beyond the urban-rural dichotomy

Past decades have seen drastically increasing research effort and progress on the study of the phenomenon of urban heat island (UHI). Despite its simplicity, this convenient concept has promoted significant advances in scientific research and policy making processes in the urban environmental community. Nevertheless, the oversimplification and inadequacy of the urban-rural dichotomy, inherited in the UHI concept, is increasingly manifest today in the continuously urbanized world. In this study, we conduct a holistic and in-depth survey of the inadequacy of the urban-rural dichotomy intrinsic to the definition of UHI, from theoretical, technical, and practical perspectives. In addition, in the light of recent research advances, we urge to radically reconceptualize UHI by proposing a novel paradigm by treating the total urban environment as a complex dynamic system. The new framework broadens the frontier of conventional urban environmental study by utilizing advanced techniques of complex systems and data sciences, including complex network theory, machine learning techniques, causal inference, etc. The reconceptualization of UHI is also expected to foster decision making and urban planning, and to avoid the one-sidedness of the singular and often too exclusive aim of heat mitigation.