Techno-material and socio-environmental model for assessing urban sustainability

The term “sustainable development” first appeared as part of discussions regarding the capacity of natural ecosystems to support the current model of economic growth, assuming a strong concern with the preservation of the planet's environmental structures. Initially, these concerns were conceived on a global scale, but soon the need to bring the discussions to the urban "locus" - the impact of large human agglomerations on the territory and its natural resources - was realized. Thus, the local scale gained importance, since most of the environmental problems originate in the local urban structures and through the lifestyle that they advocate. Cities are serious consumers and degraders of the natural ecosystem, waterproofing soils, polluting the atmosphere, altering the landscape and consuming resources. Taking the local cutout as the new parameter, new aspects in relation to the conceptual dimensions of sustainable development come to be considered, aspects closer to the reality of an urban daily life and its concerns. The relationship between society and the environment starts to be examined in a more critical way, looking for new relationship and operational alternatives in an increasingly urbanized and heterogeneous world. The urban environment is now perceived as a complex system, composed of several interrelated and interdependent subsystems that form part of a larger system. We argue, therefore, that the path towards sustainable urban development must be constructed through a systemic vision, perceiving and considering the different systems that are in synergy, interacting and influencing each other. Based on studies produced by french geographer Cyria Emelianoff and brazilian economist Henri Acselrad, in the systematization of different representations and practices on urban sustainability, this research paper aims to introduce an evaluation model able to assess the actual degree of sustainability using a set of technological and socio-environmental criteria. Such approach shows the existence of two specific fields of action: one with a techno-material basis, manifesting itself through the ecosystem's modernization of the city; and another with a socio-environmental basis, translated into the search for socio-environmental justice. The first field, based on the premises of not wasting and not polluting, would include the dimensions of an expanded technical matrix, in the search for solutions based on a technical process. They would be: i) eco-energy rationality; ii) metabolic balance; and iii) eco-systemic purity. In the second field, the materiality of the city is seen as politically constructed, where its sustainability is understood by the combination of principles of justice and ecology, suggesting that environmental degradation and social injustices have the same bases and must be analyzed together. It is necessary, in order to achieve quality of life, well-being and culture, to discuss a new ethics of sustainable development, with participation, political responsibility and social justice. The dimensions represented here would be: iv) citizen participation; v) social and cultural heritage; vi) administrative efficiency; and vii) socio-territorial equity. Thus, the sustainability of the city, and consequently the reproduction of its social relations, would be ensured not only in its materiality, but mainly as a space of true citizenship participation. This proposed evaluation model is intended to serve as a benchmark for both the formulation and evaluation of plans, projects and public policies focused on genuine sustainable development. Keywords: Urban sustainability; Sustainability representations; Sustainability practices; Evaluation model.