1 Assessing climate change impacts on sustainable development at the regional level: a case study of the province of Medenine south-east of Tunisia Authors: Mohamed Arbi Abdeladhim 1 , Mongi Sghaier 2 , Luuk Fleskens 3 , Abdallah Akari 4 Abstract This paper presents the way that multiple analytical and empirical methods are used to calculate a sustainability composite index for an ex-ante impact assessment of climate change on sustainable development in the context of arid zones in Tunisia, specifically the province of Medenine located in the south-east. To quantify the composite index, a static Computable General Equilibrium model (CGE) was adapted to the regional context. The Regional Social Accounting Matrix (RSAM) building procedure was based on a set of techniques and approaches of regionalization. The national supply and use matrix was taken as a starting point. A bottom-up approach has been used to build a regional supply and use matrix for the agricultural sector that takes into account natural resources (land and water) as intermediate inputs. The regional SAM includes ten (10) production factors, eighteen (18) production sectors producing twenty two (22) goods and services, two (2) households, urban and rural, one representative enterprise, two (2) public sectors (central and regional administration), seven (7) taxes, two (2) capital accounting accounts (Saving/Investment and changes in stocks), the rest of the world and the rest of the country. The SAM has been used to calculate the regional Gross Domestic Product (GDP). Two simulations, focused on the time horizons of 2030 with respect to a baseline centered on the year 2006, were run: i) the decline of natural capital due to the induced effects of climate change; and ii) the regional climate change adaptation strategy. Scenarios identification was based mainly on the outputs of the national strategy for adaptation to climate change (MARH and GIZ, 2007). Based on the outputs of the CGE model the impacts of climate change and adaptation strategy on the main regional economic indicators were analyzed. A multi-criteria analysis method (MCA) was used to calculate an aggregated regional sustainability indicator (composite index) for regional development. Results showed that the regional climate change adaptation strategy has a positive impact but is not sufficient to maintain sustainability level as in the current situation. Key words: Climate change, Sustainable development, Regional CGE model, Composite indicator 1 Associate researcher, the institute of Arid Regions of Medenine (IRA), 2 Professor at the institute of Arid Regions of Medenine (IRA), 3 Assistant Professor at Wageningen University 4 Professor at the University of Economic Sciences and Management of Tunis