Effects of Desertification
Environmental problems
Of all the global environmental problems, desertification is, perhaps, the most threatening for poor rural people. The most accepted definition of desertification states that it is land degradation in arid, semiarid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities. Drylands cover almost 40 percent of the total land surface of the world and are inhabited by approximately 1 billion humans dispersed over more than 100 countries. These people include many of the world 's most vulnerable, marginalized, and politically weak citizens. In spite of the progress in the understanding of the ecological dimension of this phenomenon, few communities ' wellbeing has improved by the myriad action plans and activities carried out by local, regional, or national organizations, particularly in Africa. A growing body of evidence suggests that a closer look at the social system and the role of its components is critical to understanding this frequent outcome.
Drylands are characterized by water scarcity stemming from the conjunction of low water offer (i.e., precipitation) and high water demand (i.e., water lost to the atmosphere as water vapor from soil via evaporation and from plants through transpiration). Drylands ' precipitation is highly variable through the year and occurs in infrequent, discrete, and largely unpredictable events. In turn, the high evaporative demand of the atmosphere, resulting from high air temperatures, low humidity, and abundant solar radiation, determines that water availability is the dominant controlling factor for biological processes such as plant growth and herbivore productivity. Thus drylands, though not barren, are ecosystems of low and highly variable productivity capable of limited human settlement and vulnerable to anthropogenic disturbance.
The proximate causes of desertification are complex and vary from region to region. The European Mediterranean region has a
Of all the global environmental problems, desertification is, perhaps, the most threatening for poor rural people. The most accepted definition of desertification states that it is land degradation in arid, semiarid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities. Drylands cover almost 40 percent of the total land surface of the world and are inhabited by approximately 1 billion humans dispersed over more than 100 countries. These people include many of the world 's most vulnerable, marginalized, and politically weak citizens. In spite of the progress in the understanding of the ecological dimension of this phenomenon, few communities ' wellbeing has improved by the myriad action plans and activities carried out by local, regional, or national organizations, particularly in Africa. A growing body of evidence suggests that a closer look at the social system and the role of its components is critical to understanding this frequent outcome.
Drylands are characterized by water scarcity stemming from the conjunction of low water offer (i.e., precipitation) and high water demand (i.e., water lost to the atmosphere as water vapor from soil via evaporation and from plants through transpiration). Drylands ' precipitation is highly variable through the year and occurs in infrequent, discrete, and largely unpredictable events. In turn, the high evaporative demand of the atmosphere, resulting from high air temperatures, low humidity, and abundant solar radiation, determines that water availability is the dominant controlling factor for biological processes such as plant growth and herbivore productivity. Thus drylands, though not barren, are ecosystems of low and highly variable productivity capable of limited human settlement and vulnerable to anthropogenic disturbance.
The proximate causes of desertification are complex and vary from region to region. The European Mediterranean region has a
Bibliography: 1) Adger, W. Neil, Tor A. Benjaminsen, Katrina Brown, and Hanne Svarstad. 2001. "Advancing a Political Ecology of Global Environmental Discourses." Development and Change 32:681-715. 2) Herrmann, Stefanie M. and Charles F. Hutchinson. 2005. "The Changing Contexts of the Desertification Debate." Journal of Arid Environments 63:538-55. 3) Reynolds, James F. and D. Mark Stafford-Smith. 2002. Global Desertification: Do Humans Create Deserts? Berlin: Dahlem University Press. 4) Veron, Santiago R., Jose M. Paruelo, and Martin Oesterheld. 2006. "Assessing Desertification." Journal of Arid Environments 66:751-63.