Spatial Assessment of Water-Use Vulnerability under Future Climate and Socioeconomic Scenarios within a River Basin

This case study developed a framework to assess the spatial distribution of water-use vulnerability within a river basin under various scenarios of climate change, climate change adaptation and mitigation strategies. Our indicator-based approach used a multicriteria decision-making technique and drew from the vulnerability concept of the Intergovernmental Panel on Climate Change (IPCC), which includes components of adaptive capacity, exposure, and sensitivity. To conduct a vulnerability assessment in the Han River basin, South Korea, datasets for the selected indicators from the IPCC vulnerability concept were used in conjunction with simulation results obtained from a hydrologic model. The datasets includes the existing national statistical database, climate change scenarios from representative concentration pathways (RCPs), scenarios for climate change adaptation, and mitigation strategies from shared socioeconomic pathways (SSPs). With six plausible combinations of the RCPs and SSPs, hydrological simulations using the soil and water assessment tool (SWAT) were carried out. The results for the Han River basin indicate that, of the three components of vulnerability, the greatest differences between scenarios were associated with the exposure component, which is influenced by physical climate and environmental changes. Furthermore, it was shown that vulnerability can vary with different SSPs as much as it can with different RCPs. The vulnerability results obtained with the plausible SSP scenarios markedly differed from those with the historical socioeconomic data (i.e., no SSP). This shows the importance of considering socioeconomic scenarios in studies of vulnerability and sustainability in the future.