6.3. Sensitivity, Adaptability, and Vulnerability

As noted above, climate change is only one of the causes leading to global change. As happens when there are multiple stresses, different stresses may be prevalent in different situations. In this regard, the vulnerability of certain systems and activities-such as mountain regions with snow/ice cover, low coastal areas, agriculture, water resources management and hydropower generation, and human health-are recognized as vulnerable under projected climate change scenarios. Furthermore, climate change may worsen some existing problems-such as desertification and freshwater shortages (in certain regions)-and give rise to new problems, such as the expansion of the geographical and altitudinal range of some human diseases. Warming of the atmosphere also may result in some benefits, such as the enhancement of high-latitude agriculture and reductions in the effects of wintertime diseases. Politicians and decisionmakers need to be aware of the vulnerability and adaptability of ecosystems and activities in their countries and their region, as well as elsewhere around the world, to design and implement sustainable development initiatives that take advantage of beneficial climate changes and to build strategies for international commercial exchanges in light of differential climate change impacts around the world.

Regarding the assessment of climate change impacts on different economic sectors, climatic projections at scales relevant to the production and management fields are still inadequate (as indicated in Annex B). The resolution of current GCMs is too coarse to allow reliable projections or cost/benefit analyses of possible adaptation options for the individual countries of Latin America. In some cases, however, appropriate downscaling and other techniques are available, making possible the use of GCM outputs, and regional models suitable for impact and vulnerability analysis are now being developed for this region.

The largest impacts of climate change are likely to affect natural ecosystems and sectors related to primary production, such as agriculture, livestock raising, and fisheries. Water resources are at risk in many areas. Human health and human settlements, especially in coastal lowlands and environmentally and socioeconomically marginal areas, also are vulnerable. Impacts are expected to be less severe for industry, transportation, and infrastructure outside of flood-prone areas, although increased frequency or severity of extreme events may affect these sectors.

6.3.1. Terrestrial Ecosystems: Vulnerability and Impacts

Virtually all of the world's major types of ecosystems are present in Latin America (Figure 6-4), which is characterized by high species and ecosystem diversity. Some Latin American countries-such as Mexico, Venezuela, Colombia, Ecuador, Bolivia, Brazil, and Peru-are among the world's richest in terms of terrestrial plant and animal species (Annex D; see also WRI, 1990-91; LAC CDE, 1992). Forest biomes in this region include tropical rainforests, such as the Amazon; other tropical forests in eastern Mexico, Central America, and northern South America; and the endangered Mata Atlantica in Brazil. There also are important sectors of tropical deciduous forests in the Yucatán; in the Pacific watershed of Central America, Venezuela, and Ecuador; and on the Brazilian coast from about 7°S to the Tropic of Capricorn. Mid-latitude deciduous or temperate forests are established on low-elevation coastal mountains in southern Brazil and southern Chile and to a lesser extent in southern Argentina (in the piedmont area of the Patagonian Andes). Austral forests are located on the southernmost tip of the subcontinent and on Tierra del Fuego Island. Grasslands, shrublands, and deserts-the most extensive ecosystems in the region-are found on the Mexican Pacific and Venezuelan Caribbean coasts, in northeastern Brazil, and in inland areas between Brazil and Bolivia. The Gran Chaco ecosystem is located across parts of Bolivia, Paraguay, and Argentina. The chaparral biome is on the central Chilean coast. Mid-latitude grasslands occupy extensive areas in southern Brazil, Uruguay, and central and eastern Argentina; tropical grasslands and savannas are present in Central America, the Guyanas, Venezuela, Colombia, Brazil, Paraguay, and Argentina. Arid shrublands occupy the west of Argentina and Patagonia, and hyper-arid areas exist along the west coast of Peru and northern Chile, as well as in southern Bolivia and northWestern Argentina. The Latin American region includes almost 23% of the world's potentially arable land, 12% of the current cropland, and 17% of all pastures (Gómez and Gallopin, 1991). Table 6-3 lists the surface area of different biomes in South America, and Table 6-4 lists land-cover types by country; Figure 6-4 provides information on the actual vegetation cover in South America, based on satellite imagery (Stone et al., 1994).

Figure 6-4: Major biomes in Latin America [compiled by the World Bank Environment Department Geographic Information System (GIS) Unit].

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