Uncertainty and Bias in Global to Regional Scale Assessments of Current and Future Coastal Flood Risk

• Published in: Earth's Future
• Main Authors: Hinkel, J., Feyen, L., Hemer, M., Le Cozannet, Gonéri, Lincke, D., Marcos, M., Mentaschi, L., Merkens, J, L, de Moel, H., Muis, S., Nicholls, R, J, Vafeidis, A, T, van de Wal, R, S W, Vousdoukas, M, I, Wahl, T., Ward, P, J, Wolff, C.
• Other Authors: Global Climate Forum e.V., European Commission - Joint Research Centre Ispra (JRC), CSIRO Oceans and Atmosphere, CISRO Oceans and Atmosphere, Bureau de Recherches Géologiques et Minières (BRGM), Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Cientificas España = Spanish National Research Council Spain (CSIC)-Universitat de les Illes Balears = Universidad de las Islas Baleares = University of the Balearic Islands (UIB), Christian-Albrechts-Universität zu Kiel = Christian-Albrechts University of Kiel = Université Christian-Albrechts de Kiel (CAU), Vrije Universiteit Amsterdam Amsterdam (VU), Tyndall Centre for Climate Change Research, University of East Anglia Norwich (UEA), Institute for Marine and Atmospheric Research Utrecht (IMAU), Universiteit Utrecht / Utrecht University Utrecht, University of Central Florida Orlando (UCF), ANR-17-ERA4-0002,INSeaPTION,INtegrating SEA-level Projections in climate services for coastal adaptaTION(2017)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Ice Sheet
• Online Access: https://brgm.hal.science/hal-03745681; https://brgm.hal.science/hal-03745681/document; https://brgm.hal.science/hal-03745681/file/Earth%20s%20Future%20-%202021%20-%20Hinkel%20-%20Uncertainty%20and%20Bias%20in%20Global%20to%20Regional%20Scale%20Assessments%20of%20Current%20and%20Future%20Coastal.pdf; https://doi.org/10.1029/2020ef001882

International audience This study provides a literature-based comparative assessment of uncertainties and biases in global to world-regional scale assessments of current and future coastal flood risks, considering mean and extreme sea-level hazards, the propagation of these into the floodplain, people and coastal assets exposed, and their vulnerability. Globally, by far the largest bias is introduced by not considering human adaptation, which can lead to an overestimation of coastal flood risk in 2100 by up to factor 1300. But even when considering adaptation, uncertainties in how coastal societies will adapt to sea-level rise dominate with a factor of up to 27 all other uncertainties. Other large uncertainties that have been quantified globally are associated with socioeconomic development (factors 2.3-5.8), digital elevation data (factors 1.2-3.8), ice sheet models (factor 1.6-3.8) and greenhouse gas emissions (factors 1.6-2.1). Local uncertainties that stand out but have not been quantified globally, relate to depth-damage functions, defense failure mechanisms, surge and wave heights in areas affected by tropical cyclones (in particular for large return periods), as well as nearshore interactions between mean sea-levels, storm surges, tides and waves. Advancing the state-of-the-art requires analyzing and reporting more comprehensively on underlying uncertainties, including those in data, methods and adaptation scenarios. Epistemic uncertainties in digital elevation, coastal protection levels and depth-damage functions would be best reduced through open community-based efforts, in which many scholars work together in collecting and validating these data. Plain Language Summary One of the main impacts of climate change is sea-level rise leading to more frequent flooding of low lying coastal areas through higher tides, storm surges and waves. In this context, assessments of current and future coastal flood risk at global to world-regional scales are needed to inform policy decisions on greenhouse gas reduction ...