Desertification is a process by which susceptible areas experience irreversible or long-term loss of biological productivity, which may result from climatic changes or human activity.
The human component of desertification
Researchers have paid much attention to human activity as contributing factors to - or the ultimate cause of desertification. These undertakings include:
1. Denudement of land through deforestation or overgrazing, which increases surface runoff, soil erosion, and moisture evaporation, making vegetation restoration difficult. Clearing vegetation on sandy ground can produce dune shifts, which may penetrate areas of human habitation.
2. Uncontrolled irrigation of agricultural areas, which can increase soil salinity due to water evaporation as well as soil erosion due to water runoff and wind.
3. Uncontrolled irrigation of agricultural areas, which can increase soil salinity due to water evaporation as well as soil erosion due to water runoff and wind.
4. Shortening of fallow periods, which leads to a reduction in field fertility.
5. Urban development and road construction, which increases the intensity of flooding and soil washout and may also block existing water-runoff channels, drying out vegetation that was previously downstream.
Desertification - a worldwide problem
Desertification is not a recent phenomenon. In the past, its implications were seen as a local problem and of little concern outside the affected areas. In the twentieth century, characterized by a rapidly expanding population and the attendant search for new agricultural lands, governments and international organizations realized that the drop in soil fertility that they were observing in so many areas was a serious worldwide threat. According to predictions of the UN Environmental Program (UNEP), roughly a fourth of the planet's landmass is in danger of desertification and some billion human beings are expected to be affected by its appearance. In order to meet this challenge, an international plan of action - The United Nations Convention to Combat Desertification - was developed, which came into force at the end of 1996.
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