Today, 52% of the world's population live in urban areas and this number is expected to rise to 64-69% by 2050. Cities consume most of the world's energy and materials, and are responsible of about three quarters of direct and indirect GHG emissions. Consumption patterns, however, are asymmetrical among cities and citizens. Urban metabolism, or the analysis of energy and material flows and stocks (infrastructure) that shape settlements, allows the identification not only of the dimensions of these flows and stocks, but also their main technical and socio-ecological features. These can also be evaluated from an urban political ecology perspective, that is, in terms of power relationships that define who gets access to, or control over, natural resources and other components of urban space. This article opens with a general introduction to urbanization trends, followed by a presentation of urban metabolism and urban political ecology approaches as useful analytical tools for assessing the access, management and usufruct of water in Mexico City's Metropolitan Area. A general description of the hydropolitan region of study is then offered in order to analyze urban water flows and their socioecological implications for the water-energy nexus and climate. The article concludes with a call for a paradigm change in order to transform urban settlements towards more livable, sustainable and equitable ones; a process that demands not only paying attention to the form but also to the function of urban territories within capitalist productive relationships. In this context the design and execution of public policies needed for transforming the current trend of constructing, operating, managing, and living in cities must be proactive, imaginative, and based on an integral metabolic planning that allows the adjustment of planning and policy tools to overarching contextual changes and to historical trends and socially desirable futures. Specific recommendations include the bottom-up management of water infrastructure and the guarantee of human rights to water, sanitation and a healthy environment; these are components of the ' right to the city.'
