Assessing Ecosystem Services through a multimethodological approach based on multicriteria analysis and cost-benefits analysis: A case study in Turin (Italy)

Ecosystem Services (ESs) are benefits that humans derive from nature, including climate regulation, air and water purification, soil formation, and recreation. Currently, ESs are at the center of green city policies tackling sustainability challenges. Traditionally, ESs have been assessed using monetary estimations, Environmental Impact Assessments (EIAs), and Cost-Benefit Analysis (CBA). These methods are useful for integrating environmental aspects in land use planning but have practical limitations since they focus on analyzing biophysical values and economic benefits. Due to the value pluralism of the ESs concept, intangible/extra-economic elements and the plurality of perspectives of the different stakeholders involved need to be included. Within this context, Multicriteria Decision Analysis (MCDA) allows the consideration of multiple problem dimensions and accommodates value pluralism. Based on these premises and limitations, the present paper proposes the integration of CBA and MCDA to evaluate alternative project solutions for green roof installation. The multidimensional outputs from CBA and MCDA are combined in a common aggregation procedure called COSIMA. Starting from a real case in Turin (Northern Italy), this article illustrates the application of COSIMA from the point of view of the best trade-off on the preferences of users and investors. The study results show the suitability of COSIMA for integrating all ESs values (i.e., biophysical, sociocultural, and economic) in urban governance processes.