Socio-economic vulnerability of the megacity of Shanghai (China) to sea-level rise and associated storm surges

Sea-level rise (SLR) poses a significant threat to many coastal areas and will likely have important impacts on socio-economic development in those regions. Located on the eastern coast in China, the megacity of Shanghai is particularly vulnerable to SLR and associated storm surge risks. Using the municipality of Shanghai as a case study, the possible impacts of flooding risks caused by SLR and associated storm surges on socio-economic development in the region were analysed by a Source-Pathway-Receptor-Consequence (SPRC) conceptual model. The projections of flooding risk in the study area were simulated by MIKE21 (a two-dimensional hydrodynamic model) for the three time periods of 2030, 2050 and 2100. An index system for vulnerability assessment was devised, in which flooding depth, density of population, GDP per capita, GDP per unit land, loss rate under flooding and fiscal revenue were selected as the key indicators. A quantitative spatial assessment method based on a GIS platform was established by quantifying each indicator, calculating and then grading the vulnerability index. The results showed that in the 2030 projection, 99.3 % of the areas show no vulnerability to SLR and associated storm surges under the present infrastructure. By 2050, the areas with low, moderate and high vulnerabilities change significantly to 5.3, 8.0 and 23.9 %, respectively, while by 2100, the equivalent figures are 12.9, 6.3 and 30.7 %. The application of the SPRC model, the methodology and the results from this study could assist with the objective and quantitative assessment of the socio-economic vulnerability of other similar coastal regions undergoing the impacts of SLR and associated storm surges. Based on the results of this study, mitigation and adaptation measures should be considered, which include the controlling the rate of land subsidence, the reinforcement of coastal defence systems and the introduction of adaptation in long-term urban planning.