Enhancing the Natech risk assessment framework for climate-related natural hazards

Technological accidents triggered by natural hazards, known as Natech events, occur when natural hazards compromise industrial facilities, equipment, or infrastructure, causing the release of hazardous substances from their containment systems. These scenarios are becoming increasingly relevant as climate change alters the frequency, intensity, and spatial distribution of natural hazards, including floods, storms, wildfires, droughts, and heatwaves. In this context, the thesis aims to enhance the current framework for Natech risk assessment, which is crucial to support the effective management of such accidental scenarios, focusing on climate-related natural hazards. Specifically, some methodological gaps were addressed: (i) the lack of consideration of climate change in the assessment; (ii) the limited availability of quantitative vulnerability models for wind-induced equipment damage, and (iii) the insufficient consideration of the environment as a target of risk in current methodologies. To overcome these gaps, the research combines three complementary approaches: a structured review of climate-informed hazard datasets, aimed at obtaining current and projected frequencies and severities of natural hazards; the development of generalised vulnerability models for unanchored atmospheric tanks, representing a highly vulnerable equipment type in the chemical and process industry; and the formulation of screening and consequence assessment methods explicitly considering the environment as a target, with specific applications to releases of hazardous substances in floodwaters and the marine environment. By enabling more realistic natural hazard characterisation, including wind-related phenomena in vulnerability assessment, and addressing the assessment of environmental consequences, the thesis provides an innovative and climate-adaptive framework for a more comprehensive assessment of Natech risk. As a result, climate change can be operationally incorporated into Natech risk assessment, intense wind events such as tropical and extra-tropical storms can be consistently included in quantitative analyses, and the environment can be formally treated as a target of risk.