Sustainable–Smart–Resilient–Low Carbon–Eco–Knowledge Cities; Making sense of a multitude of concepts promoting sustainable urbanization

Over the last couple of decades, metropolitan areas around the world have been engaged in a multitude of initiatives aimed at upgrading urban infrastructure and services, with a view to creating better environmental, social and economic conditions and enhancing cities' attractiveness and competitiveness. Reflecting these developments, many new categories of 'cities' have entered the policy discourse: 'sustainable cities'; 'green cities'; 'digital cities'; 'smart cities'; intelligent cities'; 'information cities'; 'knowledge cities'; 'resilient cities'; 'eco-cities'; 'low carbon cities'; 'liveable cities'; and even combinations, such as 'low carbon eco-cities' and 'ubiquitous eco-cities’. In practice, these terms often appear to be used interchangeably by policy makers, planners and developers. However, the question arises whether these categories nevertheless each embody distinct conceptual perspectives, which would have implications for how they are understood theoretically and applied in policy. In response, this article investigates, through a comprehensive bibliometric analysis, how the twelve most frequent city categories are conceptualised individually and in relation to one another in the academic literature. We hypothesize that, notwithstanding some degree of overlap and cross-fertilization, in their essence the observed categories each harbour particular conceptual perspectives that render them distinctive. This is borne out by the findings, which demonstrate robustly for the first time the conceptual differences and interrelationships among twelve dominant city categories. The 'sustainable city' is the most frequently occurring category and, in a map of keyword co-occurrences, by far the largest and most interconnected node, linked closely to the 'eco-city' and 'green city' concepts. Recently, the more narrow concepts of 'low carbon city' and 'smart city' have been on the rise, judging by their frequency of occurrence in academic journals; the latter in particular appears to have become an increasingly dominant category of urban modernization policy. On their part, ‘resilient city’ and ‘knowledge city’ represent distinct concepts, albeit with comparatively low frequency. Overall, the findings point to the need for rigor and nuance in the use of these terms, not least if one wishes to comprehend their implications for urban development and regeneration policy and practice