Quantifying processes contributing to coastal hazards to inform coastal climate resilience assessments, demonstrated for the Caribbean Sea

Scientific evidence is critical to underpin the decisions associated with shoreline management, to build climate-resilient communities and infrastructure. We explore the role of waves, storm surges and sea level rise for the Caribbean region with a focus on coastal impacts in the eastern Caribbean islands. We simulate past extreme events and a worst-case scenario, modelling the storm surges and waves, suggesting a storm surge might reach 1.5 m, depending on the underwater topography. Coastal wave heights of up to 12 m offshore and up to 5 m near the coast of St Vincent are simulated with a regional wave model. We deliver probabilistic sea level projections for 2100, with a low-probability–high-impact estimate of possible sea level rise up to 2.2 m, exceeding the 1.8 m global estimate for the same scenario. We introduce a combined vulnerability index, which allows for a quantitative assessment of relative risk across the region, showing that sea level rise is the most important risk factor everywhere but wave impacts are important on windward coasts, increasing to the north, towards the main hurricane track. Our work provides quantitative evidence for policy-makers, scientists and local communities to actively prepare for and protect against climate change. We introduce a Combined Vulnerability Index, which allows a quantitative assessment of relative risk across the region, showing that sea level rise is the most important risk factor everywhere, but wave impacts are important on windward coasts, increasing to the north, towards the main hurricane track. Our work provides quantitative evidence for policy makers, scientists, and local communities to actively prepare for and protect against climate change.