In Latin America there is ample evidence of increases in extreme climatic events and climate change. Since the TAR, unusual extreme weather events have occurred in most countries, such as continuous drought/flood episodes, the Hurricane Catarina in the South Atlantic, and the record hurricane season of 2005 in the Caribbean Basin. In addition, during the 20th century, temperature increases, rainfall increases and decreases, and changes in extreme events, were reported for several areas. Changes in extreme episodes included positive trends in warm nights, and a positive tendency for intense rainfall events and consecutive dry days. Some negative impacts of these changes were glacier retreat, increases in flood frequency, increases in morbidity and mortality, increases in forest fires, loss of biodiversity, increases in plant diseases, reduction in dairy cattle production and problems with hydropower generation. However, beneficial impacts were reported for the agricultural sector in temperate zones. According to Swiss Re estimations, if no action is taken in Latin America to slow down climate change, in the next decades climate-related disasters could cost US$300 billion per year (CEPAL, 2002; Swiss Re, 2002).
On the other hand, rates of deforestation have increased since the TAR (e.g., in Brazilian Amazonia). In Argentina, Bolivia, Brazil and Paraguay, agricultural expansion, mainly the soybean cropping boom, has exacerbated deforestation and has intensified the process of land degradation. This critical land-use change will enhance aridity and desertification in many of the already water-stressed regions in South America, affecting not only the landscape but also modifying the water cycle and the climate of the region.
As well as climatic stress and changes in land use, other stresses are compromising the sustainable development of Latin America. Demographic pressures, as a result of migration to urban areas, result in widespread unemployment, overcrowding and the spread of infectious diseases. Furthermore, overexploitation is a threat to most local production systems, and aquifer over-exploitation and mismanagement of irrigation systems are causing salinisation of soils and water and sanitation problems.
By the end of the 21st century, the projected mean warming for Latin America ranges from 1 to 4°C or from 2 to 6°C, according to the scenario, and the frequency of weather and climate extremes is very likely to increase. By the year 2020, 100 Mha of Brazil Amazonia forest will have disappeared if deforestation rates continue as in 2002/03, and the soybean-planted area in South America could reach 59 Mha, representing 57% of the world's soybean production. By 2050, the population of LA is likely to be 50% higher than in 2000, and migration from the countryside to the cities will continue.
Predicted changes are very likely to severely affect a number of ecosystems and sectors (see Figure 13.5) by:
• decreasing plant and animal species diversity, and causing changes in ecosystem composition and biome distribution,
• melting most tropical glaciers in the near future (2020-2030),
Bridge between the continents
# Coral reefs and mangroves seriously threatened with warmer SST
O Under the worst sea-level rise scenario, mangroves are very likely to disappear from low-lying coastlines
# Amazonia: loss of 43% of 69 tree species by the end of 21st century; savannisation of the eastern part
O Cerrados: Losses of 24% of 138 tree species for a temperature increase of 2°C
O Reduction of suitable lands for coffee
O Increases in aridity and scarcity of water resources
O Sharp increase in extinction of: mammals, birds, butterflies, frogs and reptiles by 2050
9 Water availability and hydro-electric generation seriously reduced due to reduction in glaciers
# Ozone depletion and skin cancer
0 Severe land degradation and desertification
# Rio de la Plata coasts threatened by increasing storm surges and sea-level rise
1 I Increased vulnerability to extreme events
Areas in red correspond to sites where biodiversity is currently severely threatened and this trend is very likely to continue in the future
Figure 13.5. Key hotspots for Latin America.
• S°Uth Brazilian America rerradi
Bridge between the continents
• S°Uth Brazilian America rerradi
• reducing water availability and hydropower generation,
• increasing desertification and aridity,
• severely affecting people, resources and economic activities in coastal areas,
• increasing crop pests and diseases,
• changing the distribution of some human diseases and introducing new ones.
One beneficial impact of climate change is likely to be the projected increase in soybean yields in the south of South America. However, the future conversion of natural habitats to accommodate soybean expansion are very likely to severely affect some ecosystems such as the Cerrados, dry and humid Chaco, Amazon transition and rainforest, and the Atlantic, Chiquitano and Yungas forests.
If the Latin American countries continue to follow the business-as-usual scenario, the wealth of natural resources that have supported economic and socio-cultural development in the region will be further degraded, reducing the regional potential for growth. Urgent measures must be taken to help bring environmental and social considerations from the margins to the fore of decision-making and development strategies (UNEP, 2002).
Climate change would bring new environmental conditions resulting from modifications in space and time, and in the frequency and intensity, of weather and climate processes. These atmospheric processes are closely interlinked with environmental, social and economic pillars on which development should be based, and all together may influence the selection of sustainable development paths. Facing a new climate system and, in particular, the exacerbation of extreme events, will call for new ways to manage human and natural systems for achieving sustainability. Future development in regional, sub-regional and local areas must be based on reliable and sufficiently-dense basic data. Consequently, any action towards sustainable development already commits governments and stakeholders to take the lead in the development of the information necessary to facilitate the actions needed to cope with the adversities of climate events, from the transitional period until a new climate system is established, and to take advantage of the new climate system's potential advantages.
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