A guiding index framework for examining urban carrying capacity

Extant studies have presented various indexes for evaluating urban carrying capacity (UCC), but there is no consistent perspective on UCC. This paper presents a guiding index framework from a holistic perspective as a reference guidance for evaluating urban carrying capacity (UCC). The framework is developed based upon the theory of sustainable urban development by addressing the fundamental question of what carrying capacities are needed to enable sustainable urban development. The framework is composed of three-layer elements, namely, top-layer pillars, intermediate-layer carriers, and bottom-layer indexes. At top-layer, there are three pillars of UCC, namely, economic carrying capacity, social carrying capacity, and environmental carrying capacity. The intermediate-layer carriers are identified based upon production factors theory, Maslow's need-hierarchy theory, and environmental factors theory. The bottom-layer presents guiding indexes which are established through comprehensive literature review, references to criteria and expert validation. The three pillars of UCC carry on different functions. Economic capacity is to maintain economic growth, which is generated by utilising effectively economic carriers, such as natural materials, human resources, and capital resources. Socially, a city should have the capacity to meet human needs through providing effective social carriers, such as food, housing, transportation, education, and medical services. Environmentally, a city should be capable to provide quality environment including land, water, and atmosphere. Each carrier is underpinned by several measurable indexes to examine the level of urban carrying capacity. The guidance and rationale of how to apply the proposed UCC guiding index framework are provided across three pillars of urban carrying capacity.