The use of the Canberra metrics to aggregate metrics to sustainability

Sustainability metrics are a set of economic, environmental, and societal indicators specifically chosen to characterize a certain multidimensional sustainability system. The difficulty in establishing criteria to consider the multiple aspects involved in sustainability increases with the complexity of the system, in general associated to its dimension. This is particularly complicated for sustainability processes because they involve not only large dimensions but the indicators are usually expressed in different units. Aggregating these metrics into a single metric represents a model calculation for sustainability and provides a tool which can be used as a sustainability decision-support. In the present work we use the Canberra metrics to model the aggregation of the three dimensions of sustainability: economics, environmental, and societal (3D) metrics into a single sustainability metric. The Canberra metrics is adequate to establish how two states are similar or dissimilar. We used a simple model to show that the Canberra metrics is independent of any specific metric (indicator) satisfying an important requirement of sustainability metrics; it treats equally the contributions of the economic, social, and environmental indicators for the sustainability indicators. This allows equally weighting the economic, social, and environmental indicators. In order to verify the applicability of the model we have considered four previously studied industrial processes and compared the results of the Canberra metrics with three previously published results of other methods, for aggregating multidimensional sustainability metrics into a single metric. The results obtained through the comparisons indicate the adequacy of the Canberra to provide very good discrimination among the processes and to be a good model metrics for sustainability.