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Climate change would affect human health indirectly by threatening food production, as a result of increased temperature, ultraviolet irradiation, sea-level rise, changes in pest ecology, ecological disruption in agricultural areas as a result of disasters, and socioeconomic shifts in land-use practices (Rosenzweig et al., 1993; Siqueira et al., 1994; Reilly et al., 1996; Haines and McMichael, 1997; Magrin et al., 1997c; Epstein et al., 1998). A link between El Niño and variation of the inter-tropical convergence zone and drought in northeastern Brazil has been described for many years (Hastenrath and Heller, 1977). Periodic occurrences of severe droughts associated with El Niño in this agriculturally rich region have resulted in occasional famines (Kiladis and Díaz, 1986; Hastenrath, 1995). Severe food shortages have occurred in this region in 1988 and 1998 (Kovats et al., 1999).
Developing countries already struggle with large and growing populations, and malnutrition rates would be particularly vulnerable to changes in food production (Patz, 1998). Changes in the distribution of plant pests have implications for food safety. Ocean warming could increase the number of temperature-sensitive toxins produced by phytoplankton, causing contamination of seafood more often and an increased frequency of poisoning. The rapid spread of cholera along the Peruvian coasts and the fact that the V. cholerae 01 isolates involved constitute a separate genetic variant that could be a result of environmental change (Wachsmuth et al., 1991, 1993)—as well as the ability of V. cholerae to survive in seawater and freshwater—make cholera a persistent health hazard (Tamplin and Carrillo, 1991). Thus, climate-induced changes in the production of aquatic pathogens and biotoxins may jeopardize seafood safety (IPCC, 1996). Increased ambient temperature has been associated with food poisoning; multiplication of pathogenic microorganisms in food is strongly dependent on temperature (Colwell and Huq, 1994; Bentham and Langford, 1995; Patz, 1998). This indicates the importance of ambient conditions in the food production process, including animal husbandry and slaughtering, to avoid the adverse effects of a warmer climate.
In Argentina, the heavily populated Paraná Delta could be seriously affected by even small changes in sea level (Kovats et al., 1998). The effects of sea-level rise may be counteracted by growing deltas as a result of the large amount of sediment coming down the Paraná and Uruguay Rivers from intense deforestation and consequential water erosion on the land of the upper basins.
Many glaciers and ice fields may soon disappear, potentially jeopardizing local water supplies that are critical for human consumption, regional agriculture, and hydroelectric power generation (Epstein et al., 1998). There is high confidence in the effects of warming on glaciers, which already are disappearing in Peru and decreasing in the high Andes between 29°S and 36°S (Canziani et al., 1997).
Climate changes are expected to have the greatest effect on health in developing nations in Latin America that already have poor and weak infrastructures. Linkages between local public health and issues of climate change must continue to be considered so that prevention and response mechanisms can be implemented against disease and other threats to human health (Kovats et al., 1998).
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