A study of the impacts of 863 natural disasters recorded over the past five decades in South America indicates that relatively rare geological phenomena, such as earthquakes and volcanic activity, have produced nearly double the number of deaths compared to more-frequently-occurring climatic and meteorological events such as floods, mudslides, storms and drought. Of the approximately 180,000 disaster-related deaths, 60% were caused by earthquakes or volcanic activity—a type of occurrence concentrated in the Andean countries such as Peru, Chile, Ecuador and Colombia. Earthquakes and volcanic activity accounted for 11% and 3%, respectively, of the events analyzed in the study.
Approximately 32% of the deaths occurred as a result of events associated with meteorological or climatic events—a category that encompasses four of every five natural disasters recorded in the region between 1960 and 2009. Disease epidemics—a type of biological disaster for which regional data are scarce, according to the survey—caused 15,000 people to lose their lives, or 8% of the total. In Brazil, 10,225 people died during the five-decade period as a result of natural disasters—slightly more than 5% of total deaths. The majority died in floods and mudslides during storms.
The study was conducted by geographer Lucí Hidalgo Nunes, a professor at the Institute of Geosciences at the University of Campinas (IG-Unicamp), for her postdoctoral thesis. It resulted in the book Urbanização e desastres naturais – Abrangência América do Sul [Overview of Urban Development and Natural Disasters in South America] (Oficina de Textos publishers), published in mid-2015. “Since the 1960s, South America’s urban population has exceeded its rural population,” says Nunes. “The most common setting for natural calamities has been urban space, which is only growing in terms of area occupied by cities and number of inhabitants.”
The situation was reversed when the focus of the analysis changed from the number of deaths to the number of people affected in each type of disaster. Of the 138 million non-fatal victims of these events, 1% were affected by epidemics, 11% by earthquakes or volcanic activity and 88% by climatic or meteorological phenomena. Droughts and floods victimized the largest number of people. Major droughts affected 57 million (41% of the total), and 52.5 million (38%) were flood victims. Brazil accounted for about 85% of the non-fatal victims of drought, mainly among those living in the Northeast, and one-third of flood victims, primarily residents of the major cities of the South and Southeast.
At an estimated US$44 billion over the course of the five decades, the monetary losses associated with the nearly 900 disasters were incurred, in 80% of the cases, as a result of climatic or meteorological phenomena. “Brazil has nearly 50% of the landmass and more than half the population of South America. But it was the locus of only 20% of disasters, 5% of deaths and 30% of economic losses associated with these events,” Nunes says. “Nevertheless, the number of people affected here was high—53% of the total number of individuals affected by natural disasters in South America. We still have vulnerabilities, but not as many as in other countries like Peru, Colombia and Ecuador.”
To write the study, Nunes compiled, organized and analyzed records of natural disasters in the past five decades in the South American countries, as well as French Guiana (an overseas department of France), that are stored in the International Disaster Database (EM-DAT). This database holds information on over 21,000 natural disasters that occurred across the globe between 1900 and the present. It is maintained by the Centre for Research on the Epidemiology of Disasters (CRED), which operates at the School of Public Health at the Catholic University of Louven, in Brussels, Belgium. “No database is perfect,” Nunes comments.” EM-DAT, for example, is lacking in records of biological disasters.” Its advantage lies in the fact that it brings together information from different sources—nongovernmental agencies, United Nations entities, insurance companies, research institutes and communications media—and stores it using a consistent methodology. This approach facilitates comparative studies.
What constitutes a disaster
Events recorded in EM-DAT as natural disasters must meet at least one of four criteria: cause the death of at least 10 people; affect 100 or more individuals; trigger the declaration of a state of emergency; or generate an appeal for international aid. In her study of South America, Nunes organized the disasters into three major categories, subdivided into 10 types of events. Geophysical phenomena include earthquakes, volcanic eruptions and dry mass movements (such as a rock that slides downhill on a rainless day). Meteorological or climatic events include storms, floods, mudslides, temperature extremes (exceptional heat or cold), droughts and fires. Epidemics are the only type of biological disaster accounted for (see table).
Climatologist José Marengo, who heads the Natural Disaster Surveillance and Early Warning Center (CEMADEN) in Cachoeira Paulista, state of São Paulo, says that beyond natural events, there are disasters that are considered technological, as well as hybrid cases. The November 2015 collapse of the Samarco-owned mine tailings dam in Mariana, Minas Gerais, which killed 19 people and released tons of toxic mud into the Doce River watershed, was unrelated to natural events. It can be classified as a technological disaster, in which human activity is linked to the causes of the event. In 2011, a 9.0-magnitude earthquake, followed by tsunamis, was the largest ever to hit Japan. It killed nearly 16,000 people, injured 6,000 others, and 2,500 were never found. It also destroyed 138,000 buildings. One of the affected buildings was the Fukushima nuclear power plant, whose reactors released radioactive material. “In that case, there was a technological disaster caused by a natural disaster,” Marengo notes.
In each succeeding decade, increasing numbers of natural disasters on the continent have been recorded, following what appears to be a global trend. “The quality of information on natural disasters has improved a great deal in recent decades. This helps swell the statistics,” Nunes says. “But there appears to be a real increase in the number of events.” According to the study, the increase in tragic events was largely due to the growing number of major meteorological and climatic phenomena that have occurred in South America. In the 1960s there were 51 events of this type. In the 2000s, the number had risen to 257. Over the course of those five decades, the incidence of geophysical disasters that cause many fatalities has remained more or less stable, and the number of epidemics has fallen.
The number of deaths from extreme events appears to have decreased after having reached a peak of 75,000 in the 1970s. In the past decade, slightly more than 6,000 deaths in South America were caused by natural disasters, according to Nunes’ survey. Historically, fatalities are concentrated in rare but large-scale events, primarily earthquakes and volcanic eruptions. The 20 events with the most fatalities—eight in Peru and five in Colombia—accounted for 83% of all deaths linked to natural phenomena between 1960 and 2009. The worst disaster was an earthquake in Peru in May 1970, with a death toll of 66,000, followed by a flood in Venezuela in December 1999 (30,000 fatalities) and a volcanic eruption in Colombia in November 1985 (20,000 deaths). On the disaster scale, Brazil is listed 9th in number of fatalities (the meningitis epidemic in 1974, with 1,500 deaths) and 19th (a mudslide triggered by heavy rains, which killed 436 people in March 1967 in Caraguatatuba, on the coast of São Paulo State).
There has also been a decrease in the number of people affected in more recent years, but the numbers remain high. Disasters In the 1980s resulted in some 50 million non-fatal victims in South America. In the past decade and the preceding one, that number fell to about 20 million.
Today, seven out of every 10 deaths in Latin America occur in cities, where haphazard land use and certain specific geoclimatic features tend to increase the local population’s vulnerability to natural disasters. Nunes compared the situation of 56 South American urban clusters with populations of more than 750,000 in relation to five factors that raise the risk of calamities: drought, earthquake, flood, mudslide and volcanic activity. Quito, the capital of Ecuador, was the only metropolis exposed to all five factors. Four Colombian cities (Bogotá, Cali, Cúcuta and Medellín) and La Paz, Bolivia, came next, with four vulnerabilities. The major Brazilian cities had two risk factors at most—drought and flood (see table). “Disasters occur as a result of a combination of natural threats and the vulnerabilities of the inhabited areas,” says researcher Victor Marchezini of CEMADEN, a sociologist who studies the long-term impacts of these extreme phenomena. “They are a socioenvironmental event.”
The costs of a disaster are difficult to measure. But based on data from the 2013 edition of the Brazilian Atlas of Natural Disasters, which uses a methodology different from that used by the Unicamp geographer to account for calamities in South America, the group led by Carlos Eduardo Young of the Institute of Economics at the Federal University of Rio de Janeiro (UFRJ) conducted a study in late 2015. Based on World Bank estimates of losses caused by disasters in several Brazilian states, Young calculated that heavy rains, floods and dry mass movements that occurred between 2002 and 2012 caused economic losses of at least R$180 billion in Brazil. Generally speaking, the poorer states, such as those in the Northeast, suffered the greatest economic losses in terms of the size of their GDP. “Vulnerability to disasters may be inversely proportional to the degree of economic development of the state,” Young says. “Climate change could heat up the issue of regional inequality in Brazil.”Republish