More than the sum of the parts: System analysis of the usability of roofs in housing estates

Abstract

Housing estates, that is, mass social housing on middle‐ and high‐rise apartment blocks, in urban areas are found all over the world with very similar constructive patterns and a multiplicity of environmental and socio‐economic problems. In this regard, such areas are optimal for the implementation of a roof mosaic which involves applying a combination of urban farming, solar energy, and harvesting rainwater systems (decentralized systems) on unoccupied roofs. To design sustainable and productive roof mosaic scenarios, we develop an integrated framework through a multi‐scale (municipality, building, and household) and multi‐dimensional analysis (environmental and socio‐economic, structural, and functional) to optimize the supply of essential resources (food, energy, and water). The proposed workflow was applied to a housing estate to rehabilitate unused rooftops (66,433 m2). First, using the Multi‐Scale Integrated Analysis of Societal and Ecosystem Metabolism methodology, we determined metabolic rates across buildings and municipality levels, which did not vary significantly (12.60–14.50 g/h for vegetables, 0.82–1.11 MJ/h for electricity, 0.80–1.11 MJ/h for heating, and 5.62–6.59 L/h for water). Second, based on a participatory process involving stakeholders to qualitatively analyze potential scenarios further in terms of preferences, five scenarios were chosen. These rooftop scenarios were found to improve the resource self‐sufficiency of housing estate residents by providing 42–53% of their vegetable consumption, 9–35% of their electricity use, and 38–200% of their water needs depending on the scenario. Boosting new urban spaces of resource production involves citizens in sites which face social and economic needs. This article met the requirements for a gold‐gold JIE data openness badge described at http://jie.click/badges.

The current and potential role of urban metabolism studies to analyze the role of food in urban sustainability

“…Some manuscripts analyzed in this research provide a starting point to design avenues forward: They illustrate the importance of engaging in fieldwork and in hybrid methods to collect and extrapolate data in data‐scarce environments but also to document embedded environmental impacts and the unequal distribution of food. For instance, the review of grey literature (Alfonso‐Piña & Pardo‐Martínez, 2014; Conke & Ferreira, 2015), participatory mapping (Shillington, 2013), participant observation (Saguin, 2014), water analysis in a laboratory (Woltersdorf et al., 2016), or the application of surveys (Karg et al., 2019; Toboso‐Chavero et al., 2021) can be made use of to research the food metabolisms of data‐scarce cities and can yield insights both into the environmental and social dimensions of the sustainability of urban food flows. UM methods are diverse—this can be seen as a weakness of the field, as it implies that the findings of these studies are not easily comparable across cases.…”