1 Quantifying processes contributing to coastal hazards to inform coastal climate resilience assessments, demonstrated for the Caribbean Sea Svetlana Jevrejeva 1,2 , Lucy Bricheno 1 , Jennifer Brown 1 , David Byrne 1 , Michela De Dominicis 1 , Andy 5 Matthews 1 , Stefanie Rynders 1 , Hindumathi Palanisamy 2 and Judith Wolf 1 1 National Oceanography Centre, Liverpool, L3 5DA, the UK 2 Centre for Climate Research Singapore, Singapore, Singapore Correspondence to: Svetlana Jevrejeva (Svetlana.jevrejeva@gmail.com) 10 Abstract. 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 1.5m, depending on the underwater topography. Coastal wave heights up to 12m offshore and up to 5m near the coast of St Vincent are simulated with a regional wave model. 15 We deliver probabilistic sea level projections for 2100, with a low probability/high impact estimate of possible sea level rise up to 2.2m, exceeding the 1.8m global estimate for the same scenario. 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, 20 scientists, and local communities to actively prepare for and protect against climate change. 1 Introduction Climate change is happening worldwide – no region on Earth has escaped it (IPCC, 2014). Caribbean small island states are particularly vulnerable to coastal climate change since the socio-economics of small islands rely on the preservation of the coastal zone. This presents a significant risk to the region’s people (IPCC, 2014; Caribbean Marine Climate Change Report 25 Card, 2017; CARIBSAVE, 2012). Small Island Developing State (SIDS), with a high concentration of population, infrastructure, and services in the low-lying coastal areas, are particularly exposed to rising sea levels, intense storms and coastal erosion. These are already posing severe threats to people (property, infrastructure and livelihoods, such as tourism and artisanal fisheries) and the marine and coastal ecosystems that support them (Rhiney, 2015). They can have a severe impact on the economy, in some cases over 100% GDP for a single event (Jevrejeva et al., 2018; Monioudi et al., 2018; Caribbean 30 Marine Climate Change Report Card 2017; CARIBSAVE, 2012). https://doi.org/10.5194/nhess-2020-46 Preprint. Discussion started: 5 March 2020 c  Author(s) 2020. CC BY 4.0 License.