Decoding vulnerability dynamics in a multi-hazard context. An Impact Chain-based exploration

During the last years, the co-occurrence of various natural hazards and the COVID-19 pandemic significantly added to the multi-hazard tapestry worldwide, translating into a boost in multi-risk research. Nevertheless, the dynamics of vulnerability across time and space within the more and more prominent multi-hazard contexts is only beginning to be explored, emerging as an intriguing but also challenging research topic.Concurrent or cascading hazards lead to compounded impacts that may increase the vulnerability to a certain hazard, while mitigation strategies can also misfire and contribute to the augmentation of vulnerability. Such convoluted interactions prove that it has never been more important to understand how and why vulnerability to natural hazards varies across scales and evolve depending on the unfolding of multi-hazards, if we are to break down the silos of hazard management approaches and devise fruitful multi-risk management plans.This study aims to explore the dynamics of vulnerability in a multi-hazard context under an Impact Chain approach, focusing on two independent, co-occurrent hazardous events that impacted Romania in 2020-2021, namely river floods and the COVID-19 pandemic. The enhanced Impact Chain builds on its previous variant developed within the Paratus Project, integrating data pertaining to hazards, impacts, exposed elements, vulnerabilities, adaptation options, and the various connections established among them. The chain is based on diverse data and information sources: scientific literature, hydrological warnings, legal documents, official medical reports, official press releases, statistical data, and grey literature in the form of news reports. The input of first responders and leaders in charge of emergency management is added to this list, integrating into the enhanced Impact Chain the perspectives of influential stakeholders.The main novelty consists of new links and element types that capture 1) the augmentation of vulnerabilities that stem from different hazard impacts, and 2) the unwelcome effects of adaptation options that are intended to mitigate vulnerabilities or impacts, but inadvertently lead to their escalation. These additions enable both the diagnosis of past or present multi-risk management, the anticipation of potential crises, shortcomings of management approaches, and the transformation of certain vulnerabilities into drivers of vulnerability.The Impact Chain informs on the focal point of mitigation efforts, also bringing to light the vulnerabilities that remained unaddressed by the adaptation options, as well as the ones that were most augmented by impacts or adaptation options working in asynergy. Due to their potential to perpetuate the failures of multi-risk management, these vulnerabilities represent the foremost considerations for future strategic initiatives.This study takes a leading initiative in research dedicated to vulnerability, being the first to address vulnerability fluctuations applied in a case study focusing on multiple co-occurrent hazards. The Impact Chain approach stands as a novel framework for examining vulnerability, also demonstrating high reproducibility across different hazards and scales. In the face of the new challenges posed by the increasingly frequent concurrent or cascading hazards, such tools can make the difference between effectively managed multi-hazards and those that escalate into unprecedented disasters.