Risk assessment and scenario analysis of coastal flood in China Seminar

Event details

In China, more than 40% of the population live in coastal areas, which contribute nearly 60% of the national gross domestic product. However, these areas are experiencing frequent storm surges and coastal flooding which has caused US$ 76.74 billion direct economic losses and 7138 fatalities from 1989 to 2014. Given China’s rapid urbanisation and global climate change, it is crucial to identify what the future impacts of coastal flooding in China will be, and how these trends may alter under changing climatic conditions (e.g. sea level rise) and anthropogenic drivers (e.g. enhanced subsidence), and what adaptation can be undertaken to reduce possible risks. Presently, there is no combined national and regional assessment of future flooding, damage and adaptation costs due to sea-level rise in China. This presentation presents impacts and costs of coastal change in China, taking into account a wide range of uncertainties in socioeconomic development, sea-level rise, local subsidence/protection data, and adaptation strategies. Quantitatively assessed damage and adaptation costs of coastal flooding in China are assessedv using the Dynamic Interactive Vulnerability Assessment (DIVA) modelling framework and a range of RCPs (Representative Concentration Pathways, RCPs) climate scenarios representing future sea-level rise, and SSPs (Shared Socio-economic reference Pathways, SSPs) representing socio-economic change. These are combined with new data on coastal type, subsidence and protection standards, plus future subsidence control plan and protection plan from government. Preliminary results show that 25-123 cm of relative sea-level rise is projected in 2100. With subsidence, 28.2 million population are expected to be flooded annually under a 100-year flood event in 2100, with 81,000 km2 areas and US$ 7.19 billion assets at risk. Furthermore, due to human-induced subsidence, flood risk is most serious in coastal mega-cites, e.g. Shanghai and Tianjin. This study emphasises that future control of subsidence and enhanced adaptation lessen flood impacts effectively.