The changing social vulnerability in Shanghai during 2000–2020 and its implications for risk management

Risk dynamics are driven not only by changes in hazard and exposure, but also the changing social vulnerability along with urban development, aging, renewal, and adaptation planning. However, there has been limited research on the spatial and temporal changes in social vulnerability, particularly at a fine scale in urban settings. To bridge this gap, our study developed a framework to consistently evaluate social vulnerability. Using Shanghai as a case study, the framework was applied to assess the social vulnerability at a township level for the years 2000, 2010, and 2020. The results revealed that the social vulnerability index decreased in 99.56 % of the townships in Shanghai from 2000 to 2020. However, there were notable variations among the four primary sub-indexes as demographic sub-index, particularly regarding an aging population, displayed a strong increase aggravating social vulnerability, in contrast to an overall decline trend of the other three sub-indexes of educational, residential, and economic. Therefore, the social vulnerability reduced along with socioeconomic development while an aging society posed a new challenge. Furthermore, 32 townships were identified with a notable rising demographic sub-index, a high flood hazard, and a low capability of disaster reliefs, demonstrating social vulnerability should be comprehensively addressed aligning with other challenges. The study highlighted the need to consider the dynamics of social vulnerability in disaster risk reduction strategies and the importance of addressing emerging challenges, such as an aging population, in urban vulnerability.