Urbanisations have a metabolism that converts inputs into outputs. Nowadays this metabolism is mainly linear, where resources are used mostly once and then discharged to the environment. Transitions towards more circular urban metabolism are thought to improve resource use efficiency and increase resilience of urban systems through functional substitution. In ecosystems diversity of metabolic functions is crucial for circulation of nutrients, for developing multiple pathways of resource flows and cascading of energy. As a result, functionally diverse eco-systems are more resilient to disturbance.
The concept of urban metabolism has not widely been applied in planning and design. One reason for this lack of applicability could be that metabolic studies aggregated data to the city or even region scale. As a result they do not show the wide diversity of functions that exist within urbanisations, which are essential to work towards more circular metabolism. Furthermore, there is a lack of fundamental understanding of the interactions of different urban functions in space and time.
Additionally, there we often approach the boundaries of data availability. For example, water and energy use data for industrial or commercial land uses are often poorly understood or mapped.