Natural hazards[1] are recurring phenomena (WMO 2021). They can be, for example, a violent storm over an uninhabited region with no human consequences and can be triggers to disasters, to serious disruption of the functioning of a community or a society at any scale (UNISDR 2017), that negatively affect individuals at the global, national, societal scales.
Death due to natural hazards is the ultimate consequence and not only is associated with the nature and extent to which a system is exposed to a natural event but also linked to socioeconomic and environmental contexts and conditions (IPCC 2022). Individuals have the capability and systems' conditions to cope, manage, and respond to such adverse conditions.
The increase in frequency and intensity of climatic extremes amplifies the severity of natural hazards (IPCC 2022; IPCC 2020) and, consequently, the challenges that social systems must manage, especially individuals who experience vulnerabilities in their daily lives (CRED-UNISDR 2018).
In Brazil, the number of individuals affected by natural hazards is high. Between 2001 and 2021, approximately 53 million people were affected by landslides, storms, droughts, floods, flash floods, and dam collapses (EM-DAT 2021). Additionally, highly vulnerable regions will increase in vulnerability because of increases in climate and weather extremes due to climate change (Marengo 2021).
Despite the number of deaths due to weather-, climate-, and water-related disasters decreasing from 1970 to 2019 (WMO 2021), two essential questions require answers: What is the most dangerous category of natural hazards? Which individuals are the most fatally affected by natural hazards? Thus, this study aims to provide, for the first time in Brazil, insights into temporal evolution, spatial distribution, and induced fatalities patterns differentiated by sex, age, and marital status in the Brazilian population from 1979 to 2019.
1.1 Scientific knowledge
Within the broader field of disaster and environmental change research, studies have been conducted on natural hazards impacts, measuring and qualifying fatal victims and their circumstances of mortality.
Many empirical studies on mortality due to natural hazards have been conducted from perspectives based on different scales of analysis, differentiated by the category of natural hazards and/or focused on a single event.
Global studies have estimated human losses, identifying the impacts of all categories of natural hazards on the human population and population subgroups, suggesting global trends. In the 1990s, Sapir (1993) provided insights into patterns and trends in disaster mortality and morbidity generated by natural and man-made hazards, affirming that they occur neither equally nor at random. Neumayer and Plumber (2017) indicate to economic, cultural, and socially constructed gender-specific vulnerabilities as responsible for different strands of global male and female mortality. Zagheny, Muttarak and Striessnig (2015) correlated the level of economic development of nations with the age and sex of fatal victims of hydro-meteorological disasters.
On the global scale, some studies have focused on a specific category of natural hazard, evaluating the possible mortality patterns, reasons for their occurrence, and the most affected subgroups. Froud and Petley's (2018) analysis of global fatal landslides indicates a strong seasonal rainfall pattern throughout the annual cycle, and the most prevalent fatalities occurred in densely occupied urban centers in the poorest countries. Likewise, Doccy et al. (2013) suggested, based on a historical review of floods events from 1980 to 2009, a global increase in the frequency of flood events, and mortality varying annually and often concentrated around large-scale events. Holle (2016) analyzed how global lightning fatalities differ between developed and lesser-developed countries and suggested higher education and awareness as measures to reduce the number of deaths. Additionally, a comparative multi-country analysis was conducted in Latin American cities to assess whether the risk of heat-related mortality is associated with age, sex, and disease status, amplified by social disparities (Bell et al. 2008).
Results of the global-scale analysis of natural hazards fatalities have demonstrated what is already known: the poorest nations and the most disadvantaged populations are those that suffer most severely (Hamza 2015) and have the largest number of deaths[2] (CRED-UNISDR 2018).
Research based on multi-hazards data in a single country can compare mortality data among categories of natural hazards ( i.e. floods, landslides, lightning, storms, hurricanes, extreme temperatures as cold and heat waves), identifying the category that kills the most people, the most affected regions, and the sociodemographic characteristics of the victims, converting national data mortality into knowledge.
An analysis conducted by a group of researchers in the United States (Thacker et al. 2008) highlights that extreme temperatures in the United States cause more deaths than other natural hazards. Despite this information, the amount of media attention and disaster relief resources is much higher for hurricane, storm, flood, and tornado events than for extreme temperatures. A study of Mexico (Jauregui-Dias et al. 2019) identified that from 2000 to 2015, the mortality from extreme weather events in Mexico remains constant. The differences between sex and age vary by the type of disaster and because of the sex division of labor. Mahapatra et al. (2018) analyzed Indian data mortality by all natural hazard causes from 2001 to 2014 for all states and union territories of India and found no consistent pattern in death rates. Extreme weather events vary in magnitude and region annually, and males are at greater risk of death than females due to their participation in outdoor work.
A study of South Korean (Myung and Jang 2011) analyzed the causes of fatalities due to meteorological disasters, the demographical characteristics of the victims, and regional distribution and found that the majority of fatalities are caused by floods due to drowning and that the place of death is distinct for male and female victims. Additionally, a study of natural hazards loss of life in Switzerland, from 1946 to 2015 (Badoux et al. 2016), recognized that most fatalities occur due to avalanches, affecting male and female victims differently. The Badoux et al. (2016) study also recognizes that improved forecasting, process detection, and warning systems are mainly responsible for the reduction of mortality.
Other authors have investigated natural hazards mortality through multi-hazards lenses, and a group of studies has focused on mortality due to specific categories of natural hazard at the national scale, with a long-term dataset, or focus on specific events. Coates (1999) was the first to publish a study on flood fatalities in Australia from 1788 to 1996 and determined that the reduction in fatalities was due to improvements in warning systems and rescue services. Ashley and Ashley (2008), based on US mortality data from 1979 to 2004, attributed the high number of flood fatalities to “people walking purposely" through water. A study of Greece demonstrated the circumstances under which most of the flood fatalities, from 1970 to 2009, occur: during nighttime, in outdoor areas, mostly vehicle-related, and from drowning (Diakakis and Deligiannakis 2017). A study of landslide and flood fatalities in Italy from 1965 to 2014 correlated the age and sex of victims to the circumstances of their deaths (Salvati et al. 2018).
Additionally, case studies have assessed the singularities of the cyclone of 1991 in Bangladesh (Bern et al. 1993), the 2003 heat wave in France (Poumadre et al. 2005), the 2002 landslide in Chuuk, Micronesia (Sanchez et al. 2009), and the 1931 hurricane, and floods in Fiji (Yeo and Blong 2010)
[1] A hazard is qualified as “a process, phenomenon or human activity that may cause loss of life, injury or other health impacts, property damage, social and economic disruption or environmental degradation” (UNDRR 2020)