From Narratives to Quantification: Co-Developing Stress-Test Scenarios for Climate Adaptation and Mitigation

Stress-testing has long been a fundamental practice in fields like finance to evaluate systemic resilience under extreme conditions. Climate scenarios however typically feature average projections and expected impacts, often neglecting critical questions such as “What if we face extremes at the upper ends of climate uncertainty, or at what levels are critical thresholds breached?”. The SPARCCLE project seeks to fill this gap by integrating stress-testing approaches into climate scenario analysis, thereby exploring the implications of extreme, but plausible climate futures under a 1.5° and a current policy scenario.For this purpose, the SPARCCLE project has actively engaged a diverse set of stakeholders from the energy, health, and finance sectors to co-develop three stress-testing storyline-and-simulation approaches. These were translated into narrative aspects of interest on various climate and socioeconomic European challenges into quantified scenarios. These scenarios illustrate conditions that stretch the limits of existing adaptation and risk management frameworks.Through structured webinars, a 2-day workshop with 30 participants including stakeholders and climate modellers, and ongoing iterative discussions to prompt aspects of interest then validate quantifications, we identified key vulnerabilities and cascading impacts of extreme climate events on critical sectors. The result are three storylines focusing on (i) Europe under heat stress, (ii) Water – too little and too much and (iii) Europe in a fragmented world. Our interdisciplinary collaboration with modelling experts encompasses methodologies ranging from simple climate models to impact models to integrated assessment models (IAMs), ensuring alignment between stakeholder-driven storylines and cutting-edge scientific insights.In this presentation, we will provide a comprehensive overview of our co-development process, detailing our methodological framework, present the three storylines and the transition of qualitative narratives into quantitative multi-model experiments. We will highlight challenges encountered and solutions devised throughout this journey. Furthermore, we will discuss how the stress-test scenario exercise can contribute to improved decision-making both for adaptation and mitigation.