Since climate change impacts are already occurring, urgent adaptive actions are necessary to avoid the worst damages. Regional authorities play an important role in adaptation, but they have few binding guidelines to carry out strategies and plans. Sectoral impacts and adaptive measures strongly differ between regions; therefore, specific results for each territory are needed. Impacts are often not exhaustively reported by literature, dataset and models, thus making it impossible to objectively identify specific adaptive measures. Usual expert elicitation helps to fill this gap but shows some issues. For the Piedmont Strategy, an innovative approach has been proposed, involving experts of private and public bodies (regional authorities, academia, research institutes, parks, associations, NGOs, etc.). They collaborated in two work group, first to identify current and future impacts on biodiversity and ecosystems, and secondly to elaborate and prioritize measures. Involving 143 experts of 46 affiliations, it was possible to quickly edit a cross-validated list of impacts (110) and measures (92) with limited costs. Lastly, a public return of results took place. This approach proved to be effective, efficient and influenced the policymakers, overcoming the tendency to enact long-term actions to face climate change. It could be used internationally by subnational authorities also in other sectors.