Abstract
Abstract. This study explores the uncertainty introduced in global assessments of coastal flood exposure and risk when not accounting for water-level attenuation due to land-surface characteristics. We implement a range of plausible water-level attenuation values for characteristic land-cover classes in the flood module of the Dynamic and Integrated Vulnerability Assessment (DIVA) modelling framework and assess the sensitivity of flood exposure and flood risk indicators to differences in attenuation rates. Results show a reduction of up to 44 % in area exposure and even larger reductions in population exposure and expected flood damages when considering water-level attenuation. The reductions vary by country, reflecting the differences in the physical characteristics of the floodplain as well as in the spatial distribution of people and assets in coastal regions. We find that uncertainties related to not accounting for water attenuation in global assessments of flood risk are of similar magnitude to the uncertainties related to the amount of sea-level rise expected over the 21st century. Despite using simplified assumptions to account for the process of water-level attenuation, which depends on numerous factors and their complex interactions, our results strongly suggest that an improved understanding and representation of the temporal and spatial variation of water levels across floodplains is essential for future impact modelling.
Highlights
Increased flooding due to sea-level rise (SLR) is a major natural hazard that coastal regions will face in the 21st century, with potentially high socio-economic impacts (Kron, 2013; Wong et al, 2014)
We find that uncertainties related to not accounting for water attenuation in global assessments of flood risk are of similar magnitude to the uncertainties related to the amount of sea-level rise expected over the 21st century
This study highlights the importance of accounting for the effects of hydrodynamic processes when assessing the impacts of coastal flooding at national to global scales
Summary
Increased flooding due to sea-level rise (SLR) is a major natural hazard that coastal regions will face in the 21st century, with potentially high socio-economic impacts (Kron, 2013; Wong et al, 2014). Broad-scale (i.e. continental to global) assessments of coastal flood exposure and risk are required to inform mitigation targets and adaptation decisions (Ward et al, 2013a), related financial needs, and loss and damage estimates. Towards these ends, a number of recent studies have assessed the exposure of area, population and assets to coastal flooding at national to global scales (Nicholls, 2004; Brown et al, 2016; Jongman et al, 2012a; Ward et al, 2013b; Arkema et al, 2013; Muis et al, 2017) as well as flood risk (Hinkel et al, 2014; Vousdoukas et al, 2018a)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
