Cape Town’s Metabolism: Insights from a Material Flow Analysis

Abstract

SummaryThis work aims to contribute to the number of urban metabolism case studies using a standardized methodology. An economy‐wide material flow analysis (EW‐MFA) was conducted on the Metropolitan Municipality of Cape Town (South Africa) for the year 2013, using the Eurostat framework. The study provides insights into the city's metabolism through various indicators including direct material input (DMI), domestic material consumption (DMC), and direct material output (DMO), among others. In order to report on the uncertainty of the data, a set of data quality indicators originating from the life cycle assessment literature was used.The results show that domestic extraction involves significant quantities of non‐metallic minerals, and that imports consist primarily of biomass and fossil fuels. The role of the city as a regional hub is also made clear from this study and illustrated by large quantities of food and other materials flowing through the city on their way to or from international markets. The results are compared with indicators from other cities and with previous metabolism work done on Cape Town.To fully grasp the impacts of the city's metabolism, more work needs to be done. It will be necessary to understand the upstream impact of local consumption, and consumption patterns should be differentiated on a more nuanced level (taking into account large differences between household income levels as well as separating the metabolism of industry and commerce from residential consumption).