Cities account for over 70% of greenhouse gas emissions and consume over two-thirds of the world’s energy. With the continued rise of urbanization, 68% by 2050 as projected by the UN, cities must be redesigned to ensure emissions, and the associated negative impacts of climate change, do not also increase proportionately. One framework through which a city’s sustainability can be analyzed is through the lens of urban metabolism; the inflows, use, and outflows of a city’s resources are viewed as analogous to the functions and processes of an organism.

To truly become sustainable, city metabolisms must become “circular,” with high quality resources being recirculated and reused throughout the system, thus diminishing the rate of resource exploitation. Through better understanding of a city’s urban metabolism, governments can implement policies targeting the points of the system with the biggest impact and increase their city’s environmental resilience. Our research focus is on Santiago de Chile and the new Ley de Responsibilidad Extendida del Productor (REP). This extended producer liability law shifts responsibility of a products’ end-of-life phase from the consumer to the producer and is a critical area of interest for the Chilean Ministry of the Environment. We analyze the flows of tires, one of the six products covered by REP; highlight potential ways in which to reduce the generation of waste and encourage its reuse; and how recycling and recovery of tires can be implemented through different stages of the product’s lifecycle.

Our team conducted a baseline material flow analysis (MFA) of tires in Santiago. Using our model we test out policy interventions that can be utilized in the city to increase its circularity; we were able to then test out more circular policy interventions that may be utilized in Santiago de Chile.