14.2.5.5. Effects on Food Production and Safety
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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