The complexity of the urban system: Profiles based on current literature and gaps with Sustainable Development Goals

The realization of sustainable development goals (SDGs) is not only the independent progress of each goal but, more importantly, to combat undesirable interactions, conflicts, and impacts, which can exactly reflect in system analysis. Cities, as the main body of development and policy implementation, the system perspectives of which provide an integrated way across the full extension. Narrowing the gaps between urban system research and SDGs helps ensure their realization with the lowest cost and highest efficiency. Therefore, this article first collects literature from the Web of Science Core Collection, eliminating out-of-scope articles and integrating citing and cited references. Then, this article profiles the final 59 urban system studies on three levels (coupling evaluation, internal element interactions, and dynamic system evolution). Finally, the gaps between the research and SDGs are discussed. Based on the results, the four aspects should be addressed to narrow the gaps: (1) Give full play to the advantages of system methods on the urban scale. (2) Give full play to the bridge role of research among various urban stakeholders. (3) Give full play to experience sharing toward sustainable urban development to avoid futile attempts. (4) Give full play to the language media role of data in policy goals, scientific research, urban needs, and other aspects.