Evaluate, drive and communicate the sustainability of complex systems: a proposal

There is a growing need to measure the sustainability (or unsustainability) of a farm among researchers, policy makers and farmers. The evaluation is useful to know the sustainability level of a farm, to drive or to monitor and evaluate the CAP application with its cross-compliance, greening and rural development measures but also to communicate to the supply chain and to the end-consumer this characteristic. A farm with livestock is a complex production system with interaction between the productive activities carried out by the farmer and the natural, social and economic environment. These interactions develop several functions measured with specific indexes and unit of measurement that make impossible express them in a single value. Aim of this work is to propose a method to express the sustainability of a complex system in an all-inclusive way transforming the expression of the considered functions into a dimensionless scale that allows to add these evaluations into a single final value. To this purpose has been identified three domains or components (environmental, territorial and social-economic) characterized by several functions (clusters). To evaluate with a dimensionless unit each cluster was applied the principle of the theory of the risk (UNI EN ISO 12100:2010). A matrix evaluation based on four grades for the farm functions (lacking, rare, probable, highly probable) and the environmental, territorial and social-economic vulnerability of the farm settlement area (light, medium, heavy, very heavy), respectively, give sixteen values classified into four classes: negligible (1), medium (2-3), high (4-8) very high (9-16). Careful attention should be given to the selection of clusters and indicators that measure them, since the functions considered will influence the outcome. The evaluation of each cluster could be eventually multiplied by a coefficient proportioned to the importance of the function expressed or to the function to be boost. The sum of the cluster evaluation gives the Sustainability Index (SI) of the farm expressed on four classes (A, B, C, D) and three sub-classes for each class (+, 0, -), representable graphically and interpretable in a simple way. In conclusion the method lends itself to be used as: i) sustainability assessment tool (to measure farm sustainability); ii) farm development tool (to increase sustainability); iii) policy makers tool (to reach or improve the CAP objectives); iv) communication tool (as commercial label).