GC Insights: Open-access R code for translating the co-occurrence of natural hazards into impact on joint financial risk

Abstract. Hydro-meteorological hazard is often estimated by academic and public sector researchers using publicly funded climate models, whilst the ensuing risk quantification uses proprietary insurance sector models, which can inhibit the effective translation of risk-related environmental science into modified practice or policy. For co-occurring hazards, this work proposes as an interim solution an open-access R code that deploys a metric (i.e. inter-hazard correlation coefficient, r) obtainable from scientific research that is usable in practice without restricted data (climate or risk) being exposed. This tool is evaluated for a worked example that estimates the impact on joint financial risk at an annual 1-in-200-year level of wet and windy weather in the UK co-occurring rather than being independent, but the approach can be applied to other multi-hazards in various sectors (e.g. road, rail and telecommunications) now or in future climates.