Climate-related flood risks and urban responses in the Pearl River Delta, China

Abstract

Growing concern on climate-related flood hazards has led to increasing interest in understanding the interactions between climate, flood, and human responses. This paper jointly investigates climate change trends, impacts on flood events, flood vulnerability and risk, and response strategies in the Pearl River Delta (PRD), a rapidly urbanizing coastal area in southeast China. Our analysis based on a reanalysis dataset and model projections are integrated with literature results, which indicates a climate scenario of increasing mean temperature, precipitation, sea level, typhoon intensity, and the frequency of extreme weather events in the PRD. These trends, together with the continuing urbanization in flood-prone areas, are expected to increase flood frequency and aggravate both the scale and degree of flooding in the PRD area. We further estimate the flood vulnerability of the 11 PRD cities using the indicator system method. The results suggest that the exposure and sensitivity of central cities (Hong Kong, Macao, Shenzhen, and Guangzhou) are very high because of highly exposed populations and assets located in lowland areas. However, the potential vulnerability and risk can be low due to high adaptive capacities (both by hard and soft flood-control measures). A novel framework on flood responses is proposed to identify vulnerable links and response strategies in different phases of a flood event. It further suggests that the flood risks can be mitigated by developing an integrated climate response strategy, releasing accurate early warning and action guidance, sharing flood-related information, and applying the advantages of online social network analysis.