IADIZA   20886
INSTITUTO ARGENTINO DE INVESTIGACIONES DE LAS ZONAS ARIDAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Land Degradation / Desertification, Society and Global Change in Latin America
Autor/es:
ABRAHAM. E. M. & R VILLALBA
Lugar:
Selfoss, Islandia
Reunión:
Congreso; The International Forum “Soils, Society and Global Change”, celebrating the Centenary of Conservation and Restoration of Soil and Vegetation in Iceland.; 2009
Institución organizadora:
State Soil Conservation Service of Iceland (SCS) en cooperación con Agencias de Naciones Unidas
Resumen:
Desertification - the land degradation of drylands due to factors ineluding climate variations and human activities - is among the most serious environmental challenges facing the world today. These general concepts become much more evident at regional and local level, where effects and synergies are starting to be visible. Conditions of risk multiply when these desertification processes synergize with those of climate change: new drivers are added to already degraded areas, leading to unknown changes. The challenge is to analyze how society and economy will prevent and adapt to these changes. This study presents examples from Latin America and Argentina, likely to be extrapolated to other drylands in the world. It ineludes comments on some eIimate change scenarios, drylands and desertification status in LAC - especially in Argentina- in relation to ongoing processes affecting the Andes and the settlements in their area of influence. There is eIear evidence that the Andes Cordillera is experiencing unprecedented environmental changes. A major retreat of ice bodies during the 20th century has been documented for the Central as well as for the Patagonian Andes (Leiva et al., 1989; Villalba et al., 2005). In many cases this has been associated with negative trends in snow precipitation and in the run-off of Cordilleran rivers. On the contrary, the increase in humidity levels in air masses coming ITom Amazonia and the Subtropical Atlantic provokes the arrival of major summer precipitations, associated with powerful storms, accompanied by severe hail. These contrasting trends are consistent with an increase in the humidity proceeding from the Atlantic in the subtropical region, and decreasing Pacific contributions since approximately 20 LS until the southem continent tipo To continue this tendency, the amount of river water volumes will depend exclusively on snowfalls. This scenario shows worrying perspectives for settlements and land uses: as the volume of snow pack diminishes, river regimes change from glacial to glacio-pluvial and then to pluvial. As a result, total run-off is expected to increase as the glaciers begin to melt, and then to decrease as the total area covered by snow and ice declines. Peak discharges will shift from the summer months, when the demand is highest, to spring and winter, with potentially severe implications for the major agricultural activity: viticulture. If we add the generalized desertification processes in practicalIy every ecosystem to this changing climatic scenario, vulnerability increases even more. In a changing world where humid places will be subject to progressive dryness, and viceversa, the map of desertification is likely to change, and so the need will emerge for those who already know about the changes entailed by desertification processes to transfer their experiences and knowledge to all those unaware of the consequences of land degradation. It is vital to link the experience generated by the UNCCD regarding concrete measures to combat desertification, with the important scientific findings of the UNFCCC. In this sense it is essential to discuss and agree on the development model we want for drylands. This paper also discusses the developments among which we can choose.