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DESERTIFICATION lect-8.pptx
- 1. Deforestation & DESERTIFICATION A Serious andDaunting Problem…… SERIOUS THREAT.................. by Dr. Jeevan Jyoti, PhD Asst. Professor, ACHS, Asmara
- 2. Whatis deforestation? Deforestationis the elimination of forest and woodland areas on the large scale.
- 3. Why is ita problem? Deforestation causes problems on both the ecological and evolutionary scales. Ecological: Deforestation eliminates key habitats that support highly specialized and sensitive species, and eliminates the Forests ability to act as natural water and air filters.
- 4. Evolutionary: Withhabitat loss comes the loss of highly specialized species, eliminating often cause widespread extinctions.
- 5. Current status Whereis deforestation still a problem? Developing countries. Tropical regions are at highest risk. Developed countries.
- 6. Causes Commercial Logging Agriculture Roads & Railways Forest fires Mining and drilling. Fuel-wood collection Residential living space.
- 7. Preventive measures Plantation Alternate energy sources
- 8. Desertification • The transformationof habitable land to desert, as by a change in climate or destructive land use. • Can be natural or human-induced. • Desertification is regarded as an environmental problem of global significance. • Came to global attention about 30 years ago.
- 9. SOME FACTS Desertificationis a worldwide phenomenon causing land degradation. It is mainly considered as a combination of natural/ climatic processes and human interferences.
- 10. Regions effected bydesertification Africa Central Asia Australia Regions in North and South America.
- 11. AREAS AT RISKFROM DESERTIFICATION
- 12. Causes ofDesertification Human activity Climatic changes (non-human induced)
- 13. • Human Actions •Overgrazing •Inappropriate numbers or types of animals • Trampling of soils •Reduction of vegetative cover •Deforestation •Fuel wood gathering •Land for farming. • Overcultivation •Economic incentives overriding agricultural knowledge •Population growth
- 14. • Estimates ofpercentage of human actions causing desertification are: • overgrazing (35%), • Deforestation (30%), • other agricultural activities (28%), • Overexploitation of fuel wood (7%)
- 15. • Climatic Effects •Natural global cycles of dry season and rain fall. • Less rain falls. • Vegetation dies. • Land becomes lighter colour and reflects more light. • Less rain means drier, more desiccated land. • Topsoil dries and turns to dust, blows away.
- 16. MAIN CAUSES FORDESERTIFICATION
- 17. • Impacts: Ecological •Accelerated soil erosion by wind or water • Wind erosion can lead to huge dust storms. • Dust can choke a city, bury an oasis, hasten desertification in other areas. • Reduction in species diversity • Loss of animal and plant species • Reduction in plant biomass.
- 18. Impacts: Economic • Lossof fertility and productivity in soils. • In China alone, about $6.5 billion annually is lost to the effects of desertification. • Worldwide $300-600 billion lost annually. • Since 1985, Kazakhstan has lost 12.5 million acres of grain-growing land.
- 19. Impacts: Human • Desertlands are inhospitable, sometimes not habitable. • 2/3 of habitable land in Africa at risk. • Loss of land means increased poverty, famine. • Food insecurity leads to more environmental refugees and displaced persons, more forced migrations.
- 20. Current Numbers Worldwide, desertification is making approximately 12 million hectares useless for cultivation every year. This is equal to 10% of the total area of South Africa. South Africa losing approximately 300- 400 million tons of topsoil every year. The Sahara desert is creeping southward at a rate of 1km/year.
- 21. The Sahel regionsare areas which experience desertification. Desertification is when a desert gradually spreads to the surrounding areas of semi-desert. Why?......
- 22. Sahelian Africa (CASESTUDY- THE SAHEL) Sahel: A semiarid region of north-central Africa south of the Sahara Desert. The West African Sahel is the most seriously affected region for desertification in the world. (severe drought 1968-1973). Four main causes of desertification identified in the Sahel: overcultivation, overgrazing, deforestation and mismanagement of irrigation
- 23. Why does theSahel suffer from desertification? DESERTIFICATION Increase in population Increase in cattle Deforestation for fire wood Grassland grazed more intensively Roots no longer hold soil together Roots may be eaten as well as grass Leaves no longer protect soil from weather Less vegetation means less protection from weather Loose top soil blown away by wind (Soil Erosion) = Loose top soil blown away by wind (Soil Erosion) = DESERTIFICATION
- 24. Preventive measures Treeplanting -Wind breaks -Prevent erosion, trap airborne dirt Improved farming -Less soil disturbance Alternative energy (to relieve fuel wood pressure). -Solar cookers for food -Wind turbines yield energy and wind breaks
- 25.