Storm Surge Risk Assessment of Immovable Cultural Heritage in the Guangdong–Hong Kong–Macao Greater Bay Area

Abstract The Guangdong–Hong Kong–Macao Greater Bay Area (GBA), with rich cultural heritage, is increasingly exposed to climate-driven disasters, especially severe storm surges. This study develops a storm surge risk assessment framework for immovable cultural heritage under climate change, by coupling the Intergovernmental Panel on Climate Change hazard–exposure–vulnerability framework with Advanced CIRCulation (ADCIRC) model simulations. A total of 11,220 heritage sites were evaluated under 20-year and 100-year return period scenarios. Key findings include: (1) based on hazard simulation, the 100-year scenario inundated more sites (3587 sites, 31.97%) than the 20-year scenario (2413 sites, 21.51%), indicating higher storm surge inundation risk, with the greatest inundation depths in the central and western GBA. Hazard levels are relatively high in Foshan, Zhongshan, and Zhuhai. (2) Exposure is mainly associated with land use characteristics and shows clear spatial heterogeneity, with Guangzhou and Foshan showing relatively high exposure in both scenarios. (3) Vulnerability is generally moderate, and relatively high vulnerability is observed in Zhuhai, Huizhou, and Zhaoqing. (4) Integrated risk differs between scenarios: Guangzhou and Foshan show prominent risk under the 100-year scenario, whereas the proportion of high-risk sites decreases under the 20-year scenario, although Shenzhen and Dongguan still show relatively high within-city proportions of Levels I and II risk sites, and risk levels are associated with heritage protection grades. The findings suggest that the GBA should adopt a zoned and prioritized management strategy by improving disaster prevention in core priority zones and prioritizing resource allocation for high-risk, unclassified heritage units to prevent irreversible damage caused by intensifying storm surges.