Down scaling of climate change scenarii to river basin level: A transdisciplinary methodology applied to Evrotas river basin, Greece

The Mediterranean region is anticipated to be (or, already is) one of the hot spots for climate change, where freshwater ecosystems are under threat from the effects of multiple stressors. Climate change is impacting natural resources and on the functioning of Ecosystem Services. The challenges about modelling climate change impact on water cycle in general and specifically on socio-economic dynamics of the society leads to an exponential amount of results that restrain interpretation and added value of forecasting at local level. One of the main challenges when dealing with climate change projections is the quantification of uncertainties. Modellers might have limited information or understanding from local river catchment management practices and from other disciplines with relevant insights on socio-economic and environmental complex relationship between biosphere and human based activities. Current General Circulation Models cannot fulfil the requirements of high spatial detail required for water management policy. This article reports an innovative transdisciplinary methodology to down scale Climate Change scenarii to river basin level with a special focus on the development of climate change narrative under SSP5-RCP8.5 combination called Myopic scenario and SSP1-RCP4.5 combination called Sustainable scenario. Local Stakeholder participative workshop in the Evrotas river basin provide perception of expected changes on water demand under to two developed scenario narratives. Transdisciplinary methodological framework to downscale global regional climate change scenario to local river basin. [Display omitted] •Impact of cliamte change of water resources management benefits from transdisicplinary methodology.•Downscaling of CC scenarii to river basin with participative workshops to enable better understanding compexity of IWRM.•Qualification and quantification of perceive changes requires extended work.•Transdisisplinary mentodology are challenging to develop and to implement, results are worht the effort.