Projecting Flood Risk Dynamics for Effective Long‐Term Adaptation

• Published in: Earth's future 2024-03, Vol.12 (3), p.n/a
• Main Authors: Schoppa, Lukas, Barendrecht, Marlies H., Paprotny, Dominik, Sairam, Nivedita, Sieg, Tobias, Kreibich, Heidi
• Format: Article
• Language: English
• Subjects: Adaptation; Boundary conditions; Case studies; Climate change; dynamics; Environmental risk; flood; Flood risk; Flooding; Floods; GDP; Gross Domestic Product; Hydrology; Levees; projection; risk; Risk assessment; Society; Socioeconomics; vulnerability
• ISSN: 2328-4277; 2328-4277
• DOI: 10.1029/2022EF003258

Flood losses have steadily increased in the past and are expected to grow even further owing to climate and socioeconomic change. The reduction of flood vulnerability, for example, through adaptation, plays a key role in the mitigation of future flood risk. However, lacking knowledge about vulnerability dynamics, which arise from the interaction between floods and the ensuing response by society, limits the scope of current risk projections. We present a socio‐hydrological method for flood risk assessment that simulates the interaction between society and flooding continuously, including changes in vulnerability through collective (structural) and private (non structural) measures. Our probabilistic approach quantifies uncertainties and exploits empirical data to chart risk dynamics including how society copes with flooding. In a case study for the commercial sector in Dresden, Germany, we show that increased adaptation is necessary to counteract the expected four‐fold growth in flood risk due to transient hydroclimatic and socioeconomic boundary conditions. We further use our holistic approach to identify solutions for effective long‐term adaptation, demonstrating that integrated adaptation strategies (i.e., combined structural and non structural measures) can reduce the average risk by up to 60% at the study site. Ultimately, our case study highlights the benefit of the model for robust flood risk assessment as it can capture unintended, adverse feedbacks of adaptation measures such as the levee effect. Consequently, our socio‐hydrological method contributes to a more systemic and reliable flood risk assessment that can inform adaptation planning by exploring the possible system evolutions comprehensively including unlikely futures. Plain Language Summary The rise in flood losses due to climate and societal changes calls for effective strategies to reduce risks. Understanding how floods interact with society and affect vulnerability is crucial in addressing this challenge. However, current flood risk assessments lack this comprehensive insight. We have developed a novel method that integrates floods and society into a single model, enabling us to comprehend how society's vulnerability to floods changes over time. Our approach examines how communities respond to floods, considering both collective (like constructing levees) and private actions (such as individual property precautions). By factoring in uncertainties and utilizing real‐world data, we improv