Understanding Desertification

Introduction Desertification is the change of land and its vegetation that makes it unable to support life, becoming like a desert. Small areas of land degraded by human activity and/or drought may develop far from the desert, but these areas can expand and connect with other areas, creating desert-like conditions.

What is desertification? “Desertification is a process of sustained land (soil and vegetation) degradation in arid, semi-arid and sub-humid areas, caused at least partly by man. It reduces both resilience and productive potential to an extent which can neither be readily reversed by removing the cause nor easily reclaimed without substantial investment.” (Nelson 1990) UNEP estimates that there are 900 million people are at risk from desertification (economically dependent on agriculture)

An example in Ethiopia Phase 1: Wood harvesting exceeds the rate of growth Phase 2: Wood becomes scarce, crop residue and dung are used for fuel, interrupting the nutrient cycle and causing soil deterioration. Phase 3: No trees left, crop residue and dung become main fuel and sold for cash; soil deterioration accelerates and crop yields decline. Phase 4: Dung becomes sole source of fuel, crop residues used to feed livestock, dramatic soil erosion. Phase 5: Total collapse, commonly triggered by a dry period, movement of people. (Nelson 1990)

Where does this occur? Sonoran Desert - Northwest Mexico to southwestern United States Atacama Desert - western base of the Andes to central Chile Diagonal strip from the Atlantic Ocean to China - includes Sahara, Arabian, Rajastan, Iranian, Taklamakan, and Gobi deserts. Namib-Kalahari - southern Africa Most of Australia

What causes it? Human agricultural activities Climatic changes deforestation overgrazing over-cultivation overuse of land area short schedule for crop rotation Climatic changes increase in temperature decrease in precipitation

Is it really happening? Desert boundaries naturally fluctuate back and forth over extended periods of time. Droughts can exacerbate apparent evidence of desertification. United Nations and other groups have decided to pursue an anti-desertification policy: Convention to Combat Desertification in Those Countries Experiencing Serious Drought and/or Desertification, Particularly in Africa (1994) Emphasizes a “bottom-up” policy, with the use of local and traditional concepts and technology

Conclusion Adjust methods of farming and irrigation in conjunction with international programs Develop greater understanding of drought and rainfall patterns Change governmental policies toward the environment