In this paper we focus on crucial issues concerning the effectiveness of evaluation of sustainability in the built environment. The paper argues that we need to rethink the evaluation of urban-building sustainability from an integrative perspective. It advances a theoretical and methodological model based on the regenerative approach, which opens up a new way to deal with the sustainability of the built environment. An enlarged definition of urban metabolism is used to carry out the integrated evaluation.
Central in it is the concept of reliability, which expresses the ability of products and processes in the built environment to be adaptive, resilient and regenerative. We use reliability in a transversal manner through the process of making the built environment sustainable, referring it both to buildings and the regenerative process triggered by sustainable actions addressed to buildings. Holistic indicators allow assessing it quantitatively or qualitatively.
Through reliability we bring regenerative thinking from a theoretical to an operational level. When referred to buildings, reliability allows considering sustainable performances not usually assessed in current evaluations. When referred to processes, it helps to understand directions of change in relation to sustainability of the built environment. Our method can be easily associated to current evaluation systems exceeding their boundaries.
During last centuries, the increase in knowledge and the associated technological advancements have determined an evolution of human societies superimposed on nature, with the results of jeopardizing natural systems. Becoming aware of natural resource depletion and environmental pollution is at the basis of the need to draw attention to a sustainable development, as defined in the Bruntland Report (WCED, 1987). This is considered a starting point of a major concern for the natural environment, which has to be interrelated with social and economic development, inter and intra generationally. Then, in recent years, the sustainability paradigm has been the leading guide for development at any scale of thought and action, pervading policies as well as practices of intervention in any field of application (Hecht et al., 2012).
The built environment is the most significant field of action for several reasons, both quantitative and qualitative: it uses natural resources and impacts the natural environment in a very relevant manner; it constitutes the socio-cultural identity of a place; it expresses the economic capacity of a society. Therefore the built environment has increasingly become the test bed of policies and practices of sustainability, the terrain for experimenting sustainable paths of governance and design so that buildings and cities have been focused subjects of interest and experimentation (Lewis et al., 2013) and sustainable buildings and cities the output of such commitment.
Now, after more than 25 years of investments in sustainability, the question is whether sustainable development is indeed sustainable (Blowers et al., 2012). The answer is arguable: it could be almost positive, if we refer to sustainability as the paradigm originating from the sustainable development definition above cited; it could be rather negative if we refer to sustainability as the ability to re-establish cooperation between the natural and the human worlds for a mutual beneficial development. The central difference resides in the approach used, which at the end defines a substantially different goal: in the first case, the sustainable development approach is aimed at reducing the natural resource depletion and the environmental impacts; in the second case, the approach is regenerative, i.e. aimed at reversing the present and persistent trend of consumption for regenerating the natural environment, indispensable for the human life (Cole, 2012a).