Quantitative assessment of building losses in China’s coastal regions due to sea-level rise under extreme climate conditions

Abstract Against the backdrop of global climate change, the superposition of extreme sea level events and long-term sea-level rise poses a severe threat to coastal regions. However, there is currently a lack of large-scale and detailed quantitative assessments for building losses caused by sea-level rise. This study takes 14 coastal provinces (autonomous regions, municipalities, and special administrative regions) in China as the research area. By integrating extreme sea level data, a digital elevation model, and building data, and by utilizing Python scripts and ArcGIS Pro software, this research quantitatively assesses the spatial distribution characteristics of land inundation and building loss under the combined effects of storm surges and tides, aiming to advance the quantitative study of building inundation exposure in coastal areas. The study finds that under sea-level rise resulting from a 100 year return period of extreme climate, the total potentially inundated area in China’s coastal provinces reaches 49 366.22 km 2 . Among these areas, buildings in 93 cities face varying degrees of inundation exposure. The losses are primarily concentrated in economically developed regions such as Jiangsu and Guangdong. In some areas, the potential density of inundated buildings exceeds 200 buildings/km 2 , which, coupled with high housing prices and dense construction, leads to extremely severe economic losses. The results of this study emphasize that adaptive protection measures based on local conditions should be formulated to mitigate the comprehensive threats of sea-level rise induced by extreme weather.