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Desertification

Desertification

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Desertification

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  1. Desertification An ancient issue Alive today

  2. What is Desertification • Land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climate variations and human activities.

  3. The process through which a desert takes over a formerly non-desert area. When a region begins to undergo desertification, the new conditions typically include a significantly lowered water table, a reduced supply of surface water, increased salinity in natural waters and soils, progressive destruction of native vegetation, and an accelerated rate of erosion.

  4. The process of making or becoming a desert (a dry barren often a sand-covered area of land characteristically desolate, waterless and without vegetation.)

  5. Erosion The wearing away of the land by running water, rain, wind, ice or other geological agents.

  6. The wearing away of land surface by wind or water, intensified by land-clearing practices related to farming, residential or industrial development, road building, or logging.

  7. Salinisation The process whereby soluble salts accumulate within the soil. Dryland salinity Areas where soil salinity levels are high enough to affect plant growth.

  8. Chapter 8 Our Growing Deserts In Herda, D.J. & Madden, Margaret. Land Use and Abuse

  9. Please make notes with particular regard to: • The land’s original condition • Current descriptions of it’s condition • Causation - why did it change? • Desertification • Salinity - Salinisation • Erosion

  10. To Summarise: • To express an idea in terms of the main points only • Express, concisely, the relevant details • To restate the main points, or ideas, as well as the most important supporting ideas, of a passage or passages, in condensed form

  11. Thriving Alexandria

  12. Because of mankind’s ignorance and indifference toward the land around him, an entire community reverted to wasteland. And Maryut is only one example of how mismanagement can lead to desertification

  13. As local human populations have increased, their escalating food needs have lengthened the cultivation period. Grain crops are now planted longer into the dry season preventing trees and grasses from reproducing as they did in the past. Much of the land has reverted to desert.

  14. As the farmers harvest their fields, the land is left barren, it’s surface broken by ploughing. Dry season winds blow away the topsoil, exposing the land to erosion. The result is desertification.

  15. When silting and salinity eventually reduced the soil’s ability to support grain and pastureland, the sheikhs moved their tribes to newer, more fertile areas, abandoning the old lands to desertification while they began the process all over again.

  16. As the limited supply of fresh water is pumped from the ground, the salt water is drawn up and spread across the soil. As the water evaporates, salt deposits are left behind, eventually building up to levels that prevent plant growth. Millions of acres of land have been lost to salinisation. These once fertile lands are today little more than great salt deserts.