Desertification is the degradation of land due to loss of soil nutrients and moisture, vegetation reduction, salinization, and accelerated wind and water erosion (Mainguet 1999). It is an international environmental challenge which poses a risk to portions of over 100 countries. Arid regions cover roughly a quarter of the global landmass, and an estimated 70 percent of these dryland areas currently experience moderate to severe desertification (UNCCD 2007). These dryland areas are home to over 2 billion people worldwide and support unique ecosystems adapted for life in arid conditions (UNEP 2007).
The water scarcity inherent in arid environments makes these regions sensitive to the effects of climate change and human development. Additionally, international market demand encourages agricultural excess in at-risk regions. Although the burden of desertification is greatest in dryland areas, the causes and consequences of desertification extend to the whole planet. Global climate change, if it continues unabated, will affect local weather patterns everywhere. Loss of biodiversity, poverty, famine, and reduced crop production pose scientific, ethical, and economic concerns. In addition, disputes over water rights and ecological refugees displaced by harsh conditions can threaten international political stability (UNCCD 2007).
Causes and Consequences
Drylands are naturally prone to climate variability with long and unpredictable cycles of drought (UNEP 2007). In contrast to isolated events, desertification refers to permanent landscape change that gradually reduces the ability of ecosystems to rebound after environmental perturbations. Human impact, coupled with natural processes, continues to exacerbate the spread of desertification. Global climate change alters temperature, rainfall, cloud cover, and wind patterns and increases the likelihood of extreme weather events. Droughts become more frequent as soil moisture and evapotranspiration decrease. In turn, lowered soil fertility restricts future plant growth. The decreased absorption of atmospheric carbon dioxide may further contribute to climate change (Sivakumar 2007).
Agriculture and unsustainable land use also have complex environmental effects on dry landscapes (Avni et al., 2006; Mortimore and Turner 2005). Arid and semi-arid regions may initially support agriculture, but repeated cultivation frequently leads to a loss of a soilâ€™s nutrients and water-holding capacity. Unsustainable farming practices, overgrazing, deforestation and irrigation all accelerate soil erosion and salinization. As available fertile land decreases, the threat of poverty and famine spreads (Williams 2001).
Present Struggles and Future Concerns
Desertification is also related to political and economic practices. In Kenya, inequity of wealth distribution leads to high variability of land holdings and inefficient concentration of agriculture that promotes soil degradation (Hogg 1987). Prior to the present crisis in Darfur, Sudan faced major ecological and social stresses as a result of rapid population growth in the late twentieth century (El-Ferouk 1996). Outside economic pressure further intensified agricultural activity, which rapidly reduced soil quality in many area causing droughts, famines, and epidemics. Mass migrations in search of water, food, and work further destabilized the country politically and socially.
In terms of global financial costs, the United Nations Environment Programme estimated in 1992 that over 42 billion U.S. dollars are lost annually as a result of desertification (Mainguet 1996). Furthermore, a statistical analysis of civil wars and interstate military engagements from 1980 to 1992 concluded that countries suffering from environmental degradation and poverty are significantly more prone to conflict (Hauge and Ellingsen 1998). These studies demonstrate that desertification appears to be directly correlated with economic, social, and political instability.
Desertification is a regional problem with global consequences. If allowed to continue unabated, it may affect the global poverty level and the global economy. The United Nations Convention to Combat Desertification has taken steps to address these issues through the implementation of many National and Regional Action Programmes (UNCCD 2007). The UNCCD programmes emphasize practical solutions and local involvement.
The desertification problem is particularly difficult to unravel because the causes and effects of soil degradation are often related. Over-cultivation strains the already scarce natural resources and perpetuates cycles of drought and poverty. Finally, many of the people most affected by desertification have the least political voice and resources to change land-use practices (UNCCD 2007).
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Hauge, W., and T. Ellingsen, Beyond Environmental Scarcity: Causal Pathways to Conflict, Journal of Peace Research, 35, 299-317, 1998.
Hogg, R., Development in Kenya: Drought, Desertification and Food Scarcity, American Affairs, 86, 47-58, 1987.
Mainguet, M., Aridity: Droughts and Human Development, Springer, New York, New York, 1999.
Mortimore, M., and B. Turner, Does the Sahelian smallholderâ€™s management of woodland, farm tress, rangeland support the hypothesis of human-induced desertification?, Journal of Arid Environments, 63, 567-595, 2005.
Sivikumar, M. V. K., Interactions between climate and desertification, Agricultural and Forest Meteorology, 142, 143-155, 2007.
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