This special issue (SI) aims to enhance our understanding of the complex, cascading interactions between natural hazards, health systems, disease outbreaks, and societal health. By compiling a high-quality collection of papers, we seek to

1. provide an overview of the state of the art for multi-hazards and health research;
2. showcase new research on the health impacts of disasters, particularly when they coincide with disease outbreaks;
3. advance modelling and measurement capabilities for multi-hazard scenarios involving public health emergencies;
4. identify synergies and trade-offs in disaster risk reduction (DRR) and adaptation strategies.

Natural hazard emergencies are fundamentally a complex interaction of natural, anthropogenic, and biological processes. For example, the COVID-19 pandemic highlighted the operational challenges of responding to events like the 2020 Zagreb earthquake amidst lockdowns and travel restrictions. Similarly, devastating floods in Pakistan in 2022 led to outbreaks of cholera and diarrhoea. These events demonstrate that a limited understanding of the cascading effects of combined disasters and diseases creates major operational, ethical, and decision-making challenges for disaster management, humanitarian, and development organizations. However, until relatively recently, there has been little engagement between the multi-hazard and health research communities to understand how these processes interact and feed off each other.

International frameworks, such as the United Nation's Sendai Framework for Disaster Risk Reduction (SFDRR) and the latest Intergovernmental Panel on Climate Change reports (Assessment Report 6 cycle), recognize the need to move beyond single-hazard thinking and address the complexities of multiple and systemic risks. The scientific community has been called upon to improve our understanding of these spatiotemporal complexities. The pre-print paper, titled Invited perspective: Redefining Disaster Risk: The Convergence of Natural Hazards and Health Crises by Sairam and De Ruiter in NHESS, for example, explores the interconnections between natural hazards, health, and society, highlighting the need for a more integrated approach.

While separate communities have advanced research on multi-hazard and systemic risks, there is a clear need to bring together a dedicated body of work on the unique intersection of disasters, diseases, health, and health systems. This SI provides that opportunity, fostering cross-disciplinary learning and identifying new research avenues. The urgency of this topic is underscored by the compounding effects of climate change on health systems and health outcomes, as well as the spatial and temporal variability of exposures and vulnerabilities to these complex hazards. This SI is part of the RiskKAN (https://www.risk-kan.org/) working group on the same topic.

Review process: This inter-journal special issue co-lists papers of different journals. Thereby, each paper was submitted to 1 particular journal and underwent the regular interactive peer-review process of that journal. Depending on the journal, the peer review was handled by regular members of the editorial board and/or by guest editors designated by the journal’s chief/executive editors.