Trends in Land Degradation in Latin America and the Caribbean, the Role of Climate Change
Latin America has a rich reserve of genetic resources. About 40% of the known living species are present in this Region. The continent represents an important reserve of cultivated land and fresh water. About one third of the forest of the world lives in their important tropical and temperate biomes, much of them are in pristine condition. Despite its genetic richness, important deforestation has affected mainly coastal ecosystems, settlement of the most part of its population. Originally, this continent had 6.93 millions km2 of forests. At present only 3.66 of its original forest coverage remain. Present rate of forest loss is 15,000 km2 yr−1, that is to say, almost 3 ha per minute. About 45% of croplands in South America and 74% in Meso-America are degraded. The arid lands are threatened by desertification and very often by droughts. Both phenomena have high social costs pushing millions of people to move to cities, creating social pressure in urban areas. This is one of the sources of crime increase and political instability in many countries. At present, the tropical rain forest continues to be cleared, mainly using fire, to open lands for annual crops and pastures. There are some biomes like temperate forest in Chile and Argentina, the Mata Atlantica in Brazil, the dry subtropical forest of the Chaco, that have been reduced to small patches.
The main source of human pressure on the environment comes from unsound agricultural practices and interventions on natural ecosystems to extract goods and services. In addition, climate has been fluctuating forcing important landscape changes in the last thousand of years. Climatic trends are evident in extensive areas of the continent. Temperature in tropical Andes shows a significant warming of about 0.33°C per decade since the mid-1970s. Minimum temperature has increased as much as 2°C in some coastal areas. In the South Western Pacific coast, rainfall has shown a clear negative trend throughout the 20th century. A contrary trend has been observed in the Atlantic coast of Argentina and Southern Brazil. Climatic variability seems to be increasing, making more frequent extreme climatic events of drought and floods. In the overall continent a rapid reduction in the permanent ice bodies is observed, mainly Andean permafrost and glaciers, which moved upward their lower front about 300 m or more in a century. Main biomes of the continent are subjected to different natural and human drivers or pressure. Among the most threatened biomes are the Caatinga in Brazil, the Amazon rain forest, temperate forest of the Patagonia, the arid and semiarid Sclerofylous forest and highlands of Puna.
Increasing climatic hazards are forcing farmers to opt low input agriculture in order to reduce economic risk. This leads to a marginal agriculture, associated with low yields and income, and consequently, social deterioration and very often, the primary cause of massive migrations. In some areas, farmers will never be able to adapt to these conditions at the required speed. Currently, prices of agricultural products are at the lower limit to support reductions on yields, so, farmers are in an extremely vulnerable condition.
KeywordsTemperate Forest Land Degradation Amazon Basin Tropical Rain Forest Human Pressure
Unable to display preview. Download preview PDF.
- Aguilar E, Peterson TC, RamÍrez Obando P, Frutos R, Retana JA, Solera M, González Santos I, Araujo RM, Rosa Santos A, Valle VE, Brunet India M, Aguilar L, álvarez L, Bautista M, Castañón C, Herrera L, Ruano E, Siani JJ, Obed F, Hernández Oviedo GI, Salgado JE, Vásquez JL, Baca M, Gutiérrez M, Centella C, Espinosa J, MartÍnez D, Olmedo B, Ojeda Espinoza CE, Haylock M, Núnez R, Benavides H, Mayorga R (2005) Changes in precipitation and temperature extremes in Central America and northern South America, 1961–2003, J Geophys Res 110, D23107, doi:10.1029/2005JD006119.CrossRefGoogle Scholar
- Campos M, Hermosilla C, Luna J, Marin M, Medrano J, Medina G, Vives M, Diaz J, Gutierrez A, Dieguez M (1997) Global Warming and the Impacts of Sea Level Rise for Central America: an Estimation of Vulnerability. Workshop organized by U.S. EPA, Chinese Taipei, USCSP, Government of The Netherlands, and NOAA, 24–28 February 1997, Taipei, Taiwan.Google Scholar
- Campos M (1996) Estimación de la Vulnerabllidad de los Recursos Hidricos, Marinos-Costeros y Agricolas en Centroamerrica, ante un Potencial Cambio Climático, USCSP/Proyecto Centroamericano sobre Cambio Climático (In press).Google Scholar
- Downing TE (1992) Climate Change and Vulnerable places: Global Food Security and country studies in Zimbabwe, Kenya, Senegal and Chile. Research Report 1, Environmental Change Unit, University of Oxford, United Kingdom, 54 pp.Google Scholar
- Friederich S (1994) Wirkung veräderter Klimatischer factorem auf pflanzenschaedlinge. In: Brunnert H, Dämmgen U (eds.) Klimaveraenderungen und Landwirtschaft, Part II Landbauforsc, Vlkenrode, 148, 1726 pp.Google Scholar
- GCOS (2003) The Second Report on the Adequacy of the Global Observing Systems for Climate in Support of the UNFCCC. WMO-IOC-UNEP-ICS, GCOS-82, Technical Document No. 1143, World Meteorological Organization, Geneva, Switzerland, 85 pp.Google Scholar
- GEF (2006) A conceptual design tool for exploiting interlinkages between the focal areas of the GEF Scientific and Technical Advisory Panel (STAP), www.unep.org/stapgefGoogle Scholar
- GEO (2002) Global Environmental Outlook 3. Past Present and Future Perspectives. UNEP. Earthscan, London. 446 pp.Google Scholar
- IPCC (2007) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. (www.ipcc.ch).Google Scholar
- Löpmeier FJ (1990) Klimaimpaktforschung aus agrarmeteorologischer sicht. Bayer Landw Jarhb 67:185–190Google Scholar
- MA (Millennium Ecosystem Assessment) (2002) Millennium Ecosystem Assessment Methods. Reid W, Ash N, Bennett E, Kumar P, Lee M, Lucas N, Simons H, Thompson V, Zurek M (eds.) Millennium AssessmentGoogle Scholar
- Mosekilde E, Mosekilde L (eds.) (1991) Complexity, chaos and biological evolutions. Plenum press, New York.Google Scholar
- NRC (2002) Abrupt Climate Change: Inevitable Surprises. Committee on Abrupt Climate Change, Ocean Studies Board, Polar Research Board, Board on Atmospheric Sciences and Climate, Division on Earth and Life Sciences, National Research Council, National Academy Press, Washington, DC, USA, 230 pp.Google Scholar
- Paeth H, Scholten A, Friederichs P, Hense A (2006) Uncertainties in climate change prediction: El Nino-Southern Oscillation and monsoons, Global and Planetary Change (In Press)Google Scholar
- Parry M, Carter TR, Konijn NT (eds.) (1988) The Impact of Climatic Variations on Agriculture. Vol. 2, Assessment in Semi-Arid Regions. Kluwer Academic Publishers, Dordrecht, The Netherlands, 764 pp.Google Scholar
- Santibañez QF (1991) Possible variations agroclimatiques en Amerique de Sud au XXIème siècle. La Météorol 38:17–24Google Scholar
- Schnoor J (1996) Environmental modeling. John Willey & Sons, Inc, A Willey-Interscience Series, New York, 683 pp.Google Scholar
- Teleginski-Ferraz S, Tércio A, da Rocha R, Santiago VC (2006) Precipitation and temperature variability over south America from 1860 to 2100. Proceedings of 8 ICSHMO, Foz do Iguaç, Brazil, April 24–28, 2006, INPE, pp. 1527–1534.Google Scholar
- Treharne K (1989) The implications of the “greenhouse effect” for fertilizer and agrochemicals. In: de Bennet RM (ed.) The Greenhouse Effect and UK Agriculture 19. Centre for Agricultural Strategy, University of Reading, United Kingdom, pp. 67–78.Google Scholar
- van Dam R, Gitay H, Finlayson M (2002) Wetlands and Climate Change 2003. Ramsar Convention COP paper. (www.ramsar.org/cop8_doc_11_e.htm).Google Scholar
- Vincent, LA, Peterson TC, Barros VR, Marino MB, Rusticucci M, Carrasco G, Ramirez E, Alves LM, Ambrizzi T, Berlato MA, Grimm AM, Marengo JA, Molion L, Moncunill DF, Rebello E, Anunciação YMT, Quintana J, Santos JL, Baez J, Coronel G, Garcia J, Trebejo I, Bidegain M, Haylock MR, Karoly D (2005) Observed trends in indices of daily temperature extremes in South America 1960–2000. J Clim 18:5011–5023CrossRefGoogle Scholar
- WMO (2003) Scientific Assessment of Ozone Depletion: 2002. Global Ozone Research and Monitoring Project, Report No. 47, World Meteorological Organization, Geneva, Switzerland, 498 pp.Google Scholar