Future Population Exposure to Flooding Due to Sea-Level Rise and Storm Surge in South Korea Where the Country’s Population Is Declining

Oh Seok Kim, Korea University
Stephen A. Matthews, Retired
Jaeheon Jung, Korea University
Kee Whan Kim, Korea University
Kwangwoo Cho, Korea Environment Institute
Keun Hyung Hong, Ministry of Oceans and Fisheries

Sea-level rise (SLR) is a global threat that will exacerbate future storms and typhoons. Given its three-sided coastal geography, the Korean peninsula will become more vulnerable to SLR and the associated floods in the future. This study aims to quantify and compare population exposure to flood due to storm surge (SS) without SLR in 2010, as compared to population exposure in 2050. By doing so, our work will portray how future SLR will impact people who live in coastal regions of South Korea. SLR and SS were modeled based on the moderate climate change scenario by averaging Representative Concentration Pathways (RCP) 4.5 and 8.5 to delineate 100-year floodplain. Gridded population projection data were produced via dasymetric mapping that is based on state-of-the-art ensemble machine learning algorithms, e.g., eXtreme Gradient Boosting (XGBoost) at a 500m pixel level. Our results show that approximately 1.79 million residents of the capital region, Seoul and Incheon, will become affected in 2050. At the national level, 4.91 million people and 12,697 square kilometers of coastal lands will be affected by floods due to future SLR and SS in 2050. Some areas will be affected less in the future because their populations will become smaller.

Keywords: Spatial Demography, Geographic Information Systems (GIS), Population projections, forecasts, and estimations, Population, Environment, and Climate Change

See extended abstract.