A critical review of parameters within urban sustainability models: how much do soil and natural resources weight?

The urgency to adopt new growth models promoting the decrease of natural resource consumption, has recently drawn the attention of researchers and policy makers to soil. This complex resource must be preserved, as it fulfills several ecological and eco-systemic functions and supports human activities. Its duality of functions determines the extreme vulnerability to degradation processes, such as sealing, desertification, loss of biodiversity. This awareness led Europe to approve the Seventh Environmental Action Community Programme (2014), which encourages Member States to adopt a more integrated approach to the transformation of soil, as a result of impacts that the land take phenomenon can produce on other natural resources and climate change processes (Yuan and Bauer 2007, 377; Wu 2008, 47). According to these brief considerations, strategies and actions aim at ensuring a more sustainable use of soil, reducing land and energy consumption and climate change effects should be promoted. In this perspective, this work describes an initial segment of a wider research oriented to define which actions allow mainly to limit the soil sealing and, at the same time, to reach energy-environmental sustainability goals too, at the urban scale. In detail, the article aims at proposing a first set of parameters measuring the consumption of soil and other urban resources, describing the main characteristics of the physical subsystem and which allows evaluating the efficiency of saving-oriented actions in the next stage of the research. To achieve this aim, a comprehensive critical review of urban sustainability models, reports and composite indicators was done, in order to provide useful insights on the measurement strictness and reliability of the numerous urban sustainability assessment reports and models, almost related to the institutional world rather than to the academic one.