Revealing the relationship between storm surge risks and coastal urbanization characteristics under sea level rise

Under the pressures of climate change and sea level rise (SLR), coastal cities like Shenzhen face escalating threats from storm surges. A critical research gap remains in the mechanistic understanding of how anthropogenic urbanization processes interact with these climatic hazards. This study takes Shenzhen as a representative hyper-urbanized coastal city and employs the MIKE 21 model to simulate exposure risks under combined SLR and storm surge scenarios. We also quantify the statistical linkages between key urbanization metrics and storm surge impacts. The results indicate that: (1) The maximum inundation extent from a 1000-year typhoon is 106.74 km2 (5.34% of Shenzhen's land area), increasing to 119.50 km2 (+11.95%) with the adverse SLR scenario; (2) Coastal urbanization characteristics correlate positively with storm surge risk, with artificial land use and reclaimed land area as key positive factors, whereas areas with high economic activities and better vegetation coverage may possess greater capacity for disaster reduction; (3) Land reclamation markedly amplifies risk, with 79.74% of reclaimed areas exposed, and artificial land on reclaimed terrain facing 1.69 times higher risk than that on original terrain; (4) High-density built-up areas and critical infrastructure experience disproportionately higher exposure, with artificial surfaces being 4.2 times more vulnerable than green spaces, underscoring the spatial inadequacy of existing green infrastructure for resilience. This study provides a scientific basis for climate adaptation and resilient spatial planning in Shenzhen and similar coastal cities.