Quantifying flood hazard is an essential component of resilience planning, emergency response, and mitigation, including insurance. Traditionally undertaken at catchment and national scales, recently, efforts have intensified to estimate flood risk globally to better allow consistent and equitable decision making. Global flood hazard models are now a practical reality, thanks to improvements in numerical algorithms, global datasets, computing power, and coupled modelling frameworks. Outputs of these models are vital for consistent quantification of global flood risk and in projecting the impacts of climate change. However, the urgency of these tasks means that outputs are being used as soon as they are made available and before such methods have been adequately tested. To address this, we compare multi-probability flood hazard maps for Africa from six global models and show wide variation in their flood hazard, economic loss and exposed population estimates, which has serious implications for model credibility. While there is around 30%–40% agreement in flood extent, our results show that even at continental scales, there are significant differences in hazard magnitude and spatial pattern between models, notably in deltas, arid/semi-arid zones and wetlands. This study is an important step towards a better understanding of modelling global flood hazard, which is urgently required for both current risk and climate change projections.
School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, UK;School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK;School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK;School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK;SSBN Flood Risk Solutions, Cardiff CF10 4AZ, UK;School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK;SSBN Flood Risk Solutions, Cardiff CF10 4AZ, UK;School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK;SSBN Flood Risk Solutions, Cardiff CF10 4AZ, UK;School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK;SSBN Flood Risk Solutions, Cardiff CF10 4AZ, UK;Department of Integrated Climate Change Projection Research, Japan Agency for Marine-Earth Science and Technology, Yokohama, 236-0001, Japan;Institute of Engineering Innovation, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan;European Centre for Medium-Range Weather Forecasts, Reading, RG2 9AX, UK;European Centre for Medium-Range Weather Forecasts, Reading, RG2 9AX, UK;Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam, 1081HV Amsterdam, The Netherlands;Deltares, 2629 HV Delft, The Netherlands;European Commission, Joint Research Centre, I-21027 Ispra, Italy;European Commission, Joint Research Centre, I-21027 Ispra, Italy;CIMA Research Foundation, I-17100, Savona, Italy;World Bank Group, 1818 H Street, NW Washington DC , District of Columbia, 20433, USA;Global Facility for Disaster Reduction and Recovery, World Bank Group, 1818H Street, NW, Washington District of Columbia, 20433, USA;Willis Re, London, EC3M 7DQ, UK;Willis Re, London, EC3M 7DQ, UK
Recommended Citation:
M A Trigg,C E Birch,J C Neal,et al. The credibility challenge for global fluvial flood risk analysis[J]. Environmental Research Letters,2016-01-01,11(9)