Measures of the vulnerability of human populations to disease and injury are not well developed. Vulnerability is intrinsically a multi-faceted characteristic. Simple "indicators" of vulnerability include average income, existing health status (as reflected in mortality rates) and proximity to potential hazards. Little research has been undertaken on population vulnerability specifically in relation to climate change and health. Progress has been made defining and forecasting areas with food insecurity (e.g., Bohle et al., 1994; Adger and Kelly, 1999; Vogel, 1998).
Woodward et al. (1998) have identified five causes of population vulnerability to ill health in the face of environmental stress: destructive economic growth that depletes capital stocks, poverty, political rigidity, dependency, and geographic isolation. With the partial exception of the first two, each of these act principally by reducing the population's capacity for adaptive response. The attainment of good public health depends on there being a responsive social order. The lack of a flexible and responsive political system and public institutions may have contributed to recent, severe impacts of climate-related disasters in parts of Asia, such as widespread forest fires in Indonesia and famine following flooding in North Korea. Dependency (such as reliance on others for information, resources and expertise) is a cause of vulnerability, because support is not always provided when it is needed. In the past, geographic isolation frequently protected populations from the introduction of infectious organisms and agricultural pests. Today, all countries are tied in to the global economy by the ease with which people and goods move around the globe. Unless new methods of protection are developed in isolated countries, remoteness may become a liability.
Vulnerability to climate variability provides a good framework to approach social vulnerability to climate change (Adger, 1996). Blaikie et al. (1994) defined vulnerability as the capacity of a population to anticipate, cope with, resist and recover from the impacts of a natural hazard. At the individual level, a complex mix of factors determines the degree to which someone's life and livelihood is put at risk by an event. These factors include: age, gender, disability, information, social engagement, income, cultural knowledge, legal rights, political power, built and natural environment, and physical resources, etc. Many social factors generate vulnerability to natural hazards at the community level; Box 14.2 illustrates some of these factors using examples from Brazil.
|Box 14.2 Vulnerability to climate variability: examples from Brazil|
Landslides during torrential rains in vulnerable urban areas kill many people each year. Squatter settlements are constructed on denuded hills as a consequence of the structure of urban land ownership and rent, and the need of the poor people to get closer to economic opportunities. For example, in February 1988 in Rio de Janeiro, 277 people were killed, 735 injured and more than 22,000 displaced due to rains, floods and landslides (Munasinghe et al., 1991)
Floods following storms in urban areas have caused epidemics of leptospirosis (Weil's disease). The vulnerability to the disease is caused by improper housing in flood-prone areas, poor drainage of rainwater and inadequate garbage disposal, which favours an increase in the population of sewer rats, the animal reservoir for the disease. This has been repeatedly reported in summertime in several coastal cities in Brazil. In some cities, such as Recife, floods could become worse with sea level rise (Neves and Muehe, 1995). Severe storms causing extensive flooding in the city of Rio de Janeiro have increased the annual incidence of leptospirosis by 10-30 fold, as has happened in the years 1988 and 1996 (Confalonieri, unpublished data)
Migration of the rural population affected by drought in the north-eastern region of Brazil has lead to the spread of endemic diseases to the periphery of urban areas. This has happened with visceral leishmaniasis, which was re-introduced in the cities of Teresina and Sao Luis (Silva et al., 1997; Costa, 1993) following migrant waves of peasants affected by severe droughts in El Niño years, in the late 1980s and early 1990s.
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