A framework for multi-hazard risk indicators

The occurrence of multiple hazards poses significant risks to both human lives and assets. These risks often surpass those associated with individual hazards as they result from the interaction of natural hazards through simultaneous, cascading, or cumulative incidents. In several European regions, vulnerable to a range of climatic extremes, the society and environment are expected to undergo significant impacts in the next few decades. This is attributed to the rising frequency and severity of multi-hazard events, which are closely tied to changing climatic conditions. In this context, the aim of this work is to develop and test a new framework for multi-hazard risk indicators that are suitable for use in risk-based assessments and decisions making. Indicators are used within different disciplines, offering insights into hazards, risk, resilience, vulnerability and other impacts related to climate change, amongst other factors. Such indicators can be used to model interacting hazards and cascading impacts within risk assessments, including a decision support system for multi-hazard disaster risk. This work, supported by a systematic literature review grounded on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA), introduces a framework for a suite of simple and usable multi-hazard indicators that balance complexity and usability to enable their uptake within natural hazard risk assessments (e.g., multi-hazard/risk rate). We adopt the following definition Indicators are observable and measurable characteristics that can be used to simplify information to help understand the state of a concept or phenomenon, and/or to monitor it over time to show changes or progress towards achieving a specific change. The development of these indicators prioritises the needs of end-users in disaster risk management, aiming to overcome limitations associated with their evolution being driven by climate scientists, without considering sectoral impacts or risk-based assessments. The framework for indicator development can contribute valuable insights for progressing multi-hazard risk management policies globally, particularly in regions experiencing an increased susceptibility to multi-hazard events. The research has been carried out within the framework of the Horizon Europe project MEDiate (Multi-hazard and risk-informed system for Enhanced local and regional Disaster risk management). The primary objective of this project is to create a decision-support system (DSS) for disaster risk management that takes into account the complexities of multiple interacting natural hazards and their cascading impacts. The framework is implemented on four interactive multi-hazard pairscompounding coastal and riverine flooding, extreme heat and drought, extreme wind and precipitation, and extreme precipitation and landslidesin four European testbeds: Oslo (Norway), Nice (France), Essex (UK), and Mlaing (Iceland), respectively.