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Cold and warm fronts, tropical cyclones, and severe convergence are some of the most frequent phenomena that produce floods, droughts, mud and snow slides, heat waves, frosts, and climate-related fires throughout Latin America. These extreme events produce direct and indirect impacts on productivity and affect the quality of life for Latin Americans. A hazard (extreme climate phenomenon) becomes a disaster when it outstrips the ability of a country or region to cope.
There are subregions of Latin America where the occurrence of extreme events is very frequent. Central America and southern Mexico often experience the effect of tropical cyclones and associated heavy rain, flooding, and slides. For northwestern South America and northeastern Brazil, many of the extremes that occur are highly related to El Niño.
Sometimes these extreme events could be magnified to such a level (extreme of extremes) that the impact becomes a disaster. In Latin America, interaction with other complex phenomena, such as interannual or interdecadal oscillations, can contribute to create the appropriate conditions to produce a disastrous impact. Examples of these extraordinary extreme events include Hurricane Mitch in Central America, heavy rains in Venezuela, some of the most severe droughts in northeastern Brazil, and variations in ocean currents during El Niño for Peru and Ecuador.
Emanuel (1987, 1991) has suggested that warmer surface conditions and colder lower stratospheric temperatures would result in stronger hurricanes. Data for the eastern Pacific region indicate that the number of strong hurricanes in the region has been increasing since 1973 (Whitney and Hobgood, 1997). Such changes may represent a major environmental threat for countries such as Mexico (Jáuregui, 1995) and the Central American isthmus.
Some of the relatively weak cold surges may exhibit unusual intensity, causing frosts and low temperatures in coffee-growing areas of southeastern Brazil, resulting in heavy damage and losses in coffee production (Marengo et al., 1997). In the Mexican Altiplano, dry atmospheric conditions result in radiative cooling and frosts even during the summer (Morales and Magaña, 1998).
Even though it is still uncertain how global warming may affect the frequency and intensity of extreme events, extraordinary combinations of hydrological and climatic conditions historically have produced disasters in Latin America. Thus, in assessing vulnerability and adaptation mechanisms, it is necessary to consider the potential influence that global warming might have on extreme events.
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