Today the cities of the world are home to almost 4 billion people (54% of the world population) and in the coming years this number will grow considerably. Billions of tons of raw materials are used for their construction and operation, such as water, food, fuel, building materials, etc; once used, they are discarded in the environment as pollution and waste. However, resource consumption and waste disposal are not the only problems to be addressed; issues related to sustainability also include social and economic elements, such as mobility, housing availability, employment, health, education, citizen participation in decision-making processes.
This book presents the issues related to urban sustainability, proposing solutions based on the vision of the city as a "living organism". Urban metabolism is a holistic model that allows to trace incoming and outgoing flows (of water, energy, food, people, materials) and that can be used to analyze the functioning of urban areas in relation to the use of resources and infrastructures, providing data and tools to plan and manage the urban environment in a more sustainable way. The book also contains experts contributions and some best practices that implemented urban systems sustainability for the planet and the citizens.