Land suitability for viticulture under present and future climate conditions: Sardinia as a regional case study

Climate change is affecting the viticultural sector worldwide, impacting phenology, yield, and grape quality, potentially making some traditional viticulture regions unsuitable in the future. Despite numerous suitability studies conducted on pan-European and national scales based on climatic factors, high spatial resolution analyses that integrate climatic factors with edaphic and topographic factors are needed at the regional scale. This study uses a GIS-based Multi-Criteria Decision Analysis (MCDA) approach integrated with the Analytical Hierarchy Process (AHP) to assess viticultural suitability in Sardinia (Italy) under current and future climate, by incorporating five bioclimatic indices, five soil parameters, and two topographic variables. Bioclimatic indices were calculated for a reference period (1981-2010) and projected climate scenarios (RCP 4.5 and 8.5 for 2021-2050 and 2036-2065), while soil and topography were considered constant across scenarios. The weighting of the indicators was based on expert opinion, collected through a survey, and the results indicated that the climate is the most influential factor (weight = 0.52), followed by soil (0.36) and topography (0.12). Bioclimatic suitability under future scenarios is projected to decrease in currently highly suitable areas (S1), by increasing the moderately suitable (S2) class, particularly under RCP 8.5. However, the multicriteria analysis revealed overall stability, mostly due to favorable soil characteristics. The study underscores the relative resilience of the viticultural sector in Sardinia and the importance of combining climatic, edaphic, and topographic data for land suitability assessment.