A Stress Test for Climate Change Impacts on Water Security: a CRIDA Case Study

Abstract Since the impacts of climate change will be felt most directly through changes in water availability and water security, adequate tools are required to support water resources management decisions for the medium and long term. The Climate Risk Informed Decision Analysis (CRIDA) provides a pathway for more localized vulnerability assessments of water resources under climate change, while encompassing the uncertainty of current global climate projections. Within this framework, this paper demonstrates a climate stress test to identify changes in key performance indicators defined through local stakeholder consultations using a bottom-up approach. When applied to a case study in the Limari River basin in Chile, the stress test highlights the vulnerability of the reservoir system to climate variability and change, through a comprehensive analysis of 43 Global Circulation Models, of which 34 were retained. The Level of Concern (LoC) was defined as high, due to a high plausibility for entering into adverse water security conditions, that are expected to provoke a significant impact in the highly productive areas of the watershed. As demonstrated by the case study, the climate stress test provides a relevant assessment tool for potential climate change impacts on critical components of the water system in vulnerable catchments.