Evolving multi-hazard paradigms in a nutshell

Understanding multi-hazard approaches is crucial in an era of escalating natural hazards leading to disastrous impacts on Earth’s citizens. Triggered by the increasing frequency and severity of these events, this brief post provides a concise yet comprehensive overview of evolving paradigms in multi-hazard research and management. By exploring definitions, historical developments, and current trends, we highlight the critical importance of integrated strategies in mitigating impacts on society all in a nutshell.

Foundation: Multi-hazard concept history at one glance

It is important to acknowledge that the encouragement of multi-hazard approaches began with the work of Hewitt and Burton (1971) [1]; they emphasised the necessity of systematic cross-hazard approaches in understanding the hazard landscape of an area. However, the importance of multi-hazards was pronounced when this concept was first introduced in the United Nations’ Agenda 21 for Sustainable Development, held in Rio de Janeiro, Brazil, in 1992 under the title of “complete multi-hazard research” [2]. Subsequent international frameworks, including the Johannesburg Plan (UN, 2002), the Hyogo Framework for Action (2005) [3], and the more recent Sendai Framework for Disaster Risk Reduction (2015-2030) [4], have further underscored the importance of these strategies. The Sendai Framework, for instance, highlights the necessity for multi-hazard approaches, defining them as “the selection of multiple major hazards faced by a country, including the specific contexts in which hazardous events may occur simultaneously, cascadingly, or cumulatively over time, with consideration for their potential interrelated effects” [2]. 

Since then, the field has seen an exponential increase in research across various dimensions of multi-hazards, ranging from social to physical aspects [for example, 5-6]. This trend has persisted, reaching a point where the term “multi-hazard” has become a common buzzword in nearly every project related to natural hazards [7].

The unfolding story: Initial and ongoing confusion

Initially, due to the unclear and varied definition of multi-hazards, studies mainly adopted approaches based on their own perceptions of this term, ranging from an “all-hazards-at-a-place approach” [1] to “more-than-one-hazard” approaches [8]. Kappes (2012) [8] provided an early definition of “multi-hazard” within the framework of risk reduction as “the totality of relevant hazards in a defined area”. This concept aimed to cover all potential environmental or man-made threats that could lead to harm, damage, or degradation. However, the criteria for defining the relevance of a hazard have been subject to debate, ranging from the introduction of a damage-based cut-off point for relevance by Hewitt and Burton (1971) [1], to the European Commission (2011) [9] proposing criteria based on the scale and impact of a hazard [8]. 

The traditional approach treats each hazard individually as a single event, often confusing decision-makers, particularly in critical circumstances. Managing natural hazards in isolation fails to recognise the interconnection and potential cascading effects that can arise from multiple hazards [8, 10-11]. Gill and Malamud (2016) [11] argue that narrowing the focus to a limited portion of the entire Earth system instead of understanding its dynamic interactions as a whole could lead to decisions that increase vulnerability to overlooked hazards. Consequently, the prevalence of single-hazard approaches inevitably leads to a distortion of management priorities.