A comparative evaluation of urban metabolism methodologies

Globally, urban metabolism analysis has become a significant tool for the study of urban ecosystems. Urban metabolism as a concept represents an integrated platform for analyzing the urban dynamics and supporting the planning processes in cities as social-ecological systems within the concept of sustainability. Moreover, urban metabolism provides relevant information for cities in terms of energy efficiency, material flows, and waste management. Since the first study of urban metabolism by Wolman in 1965 until today the scientific committee developed and improved different methodologies and indicators for the urban metabolism analysis. This study focuses on the comparison of the three main methods that have been widely used for the study of urban metabolism which are emergy analysis, material flow analysis and ecological footprint analysis. Each one of the methodologies is based on specific principles and indicators, presenting different strengths and weaknesses. As a general conclusion, urban metabolism methodologies are facing problems related to data scarcity at the city level, the fluid nature of urban metabolisms, the lack of standardization, difficulty in tracking informal or decentralized systems, the lack of data accuracy, difficulty in understanding specific concepts.