City and regional planners have recently started exploring a circular approach to urban development. Meanwhile, industrial ecologists have been designing and refining methodologies to quantify and locate material flows and stocks within systems. This Perspective explores to which extent material stock studies can contribute to urban circularity, focusing on the built environment. We conducted a critical literature review of material stock studies that claim they contribute to circular cities. We classified each article according to a matrix we developed leveraging existing circular built environment frameworks of urban planning, architecture, and civil engineering and included the terminology of material stock studies. We found that, out of 271 studies, only 132 provided information that could be relevant to the implementation of circular cities, albeit to vastly different degrees of effectiveness. Of these 132, only 26 reported their results in a spatially explicit manner, which is fundamental to the effective actuation of circular city strategies. We argue that future research should strive to provide spatial data, avoid being siloed, and increase engagement with other sociopolitical fields to address the different needs of the relevant stakeholders for urban circularity.

This paper aims to apply an intersectional environmentalist lens to the circular economy (CE) transition in Flanders. CE discourse often takes a deterritorialised approach, that is, a focus on innovation and growth. This approach tends to neglect local knowledge and background skills that can inhabit and work with landscapes in balanced ways to enable a fully circular society. This knowledge is partly embodied by “nobodied” actors. After introducing relevant terminology, this article draws upon a collaborative autoethnography which integrates autobiographies of authors’ experiences of circularity in projects with “nobodied” CE actors, and ethnographic notes on the Flemish context in which the CE discourse developed. The reflections unearth how a lack of an intersectional environmentalist lens in the CE rhetoric “nobodies” informal CE actors and practices. We show how they do not matter in a circular economy in a deterritorialised approach, but how they matter in a circular landscape view.

From a sustainable material management perspective, vacant houses represent material stock and still have potential in the circular economy. This article addresses two aspects of understanding and managing vacant houses: the difficulty of understanding their spatial and temporal patterns and the management of the social costs behind the phenomenon of vacant houses. These aspects are approached by combining a 4D GIS analysis with expert interviews and additional qualitative tools to assess the spatial and temporal dimension of vacant houses. Furthermore, this manuscript presents a tool to estimate the obsolete dwelling material stock distribution within a city. The case of the city of Kitakyushu demonstrates the relationship that exists between the historical trajectories of housing norms and standards, such as comfort, cleanliness, safety, and convenience, and the dynamics of the built material stock and demography for three selected neighbourhoods. The results show that the more locked-in a district is in terms of “obsolete norms and codes”, the more likely it is that the obsolete stock is dead, and consequently, urban mining should be considered. The article concludes that a revisiting of the norms and standards of convenience and other domains is one of the prerequisites of the transition toward a circular built environment and the prevention of obsolete stock accumulation.