Understanding desertification
Download
1 / 9

Understanding Desertification - PowerPoint PPT Presentation


  • 183 Views
  • Uploaded on

Understanding Desertification. Introduction. Desertification is the change of land and its vegetation that makes it unable to support life, becoming like a desert.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Understanding Desertification' - kaz


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Introduction
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
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
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
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
What causes it?

  • Human agricultural activities

    • 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
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
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


ad