Keywords: Climate Change Impact, Coastal Inundation, IPCC RCP / SSP Scenarios, Coastal Resilience, Numerical Modelling, Perth, Sea Level Rise
In view of the ongoing global climate changes, low-lying coastal cities of the world, including Perth in Western Australia, are encountering escalating threats from extreme wave events along with sea level rise. This research focuses on the compounding impacts of climate change on wave heights and coastal inundation forms using an integrative numerical modelling approach. Implementing high-resolution bathymetric data, 45-year offshore wave hindcasts, and IPCC AR6 sea-level rise projections across different Representative Concentration Pathways, the work has been able to simulate coastal hazard scenarios using DHI MIKE 21. The existing literature points out seasonal swell regimes and low-frequency cyclonic activity as the main drivers of Perth’s vulnerability, but there are few studies that describe it risk under changing climate. This research addresses this gap by linking Extreme Value Analysis (EVA) to scenario-based modelling in order to profile significant wave characteristics and coastal flooding changes. The outcomes show that historic and future Hags differ up to 10% in the prevalence of significant wave heights across major prevailing swell directions (180°, 225°, 270°) with significant wave height overstepping 9.2 m under the extreme RCP 8.5 (SSP5-8.5) LC scenarios. Inundation footprints for Fremantle and Mullaloo back under 100-year return periods and high-emissions scenarios significantly reflect inland penetration, posing a serious threat to the coastal environment, and showcasing the importance of adaptive coastal infrastructure development and resilience planning. The study emphasizes the effectiveness of numerical methods to understand and estimate climate change through coastal interactions. Therefore, it should be considered as the basis of proactive adaptation guidelines. The results add to the ongoing academic conversation around climate-resilient urban planning and promote the enhancement of predictive skills for coastal hazard assessments under deep uncertainty.