1. DesertificationDesertification Speaker: Cheng Jingxia Group : 13 Group : 13

2. Contents 1.The current situation of desertification 2.The cause of desertification 3.The harm of desertification 4.How to prevent and control the desertification?

11. Definition Desertification is arid, semi-arid and dry sub-humid areas of land degradation, which caused by various factors, including climatic variations and human activities.

12. Current situation Desertification is a worldwide ecological environmental problem. Over 100 countries were affected by desertification. There are more than 12 million people have been suffered the direct threat of

13. desertification. Although the people of all countries are going to fight against desertification, but desertification is expanding at

14. the speed of 50 to 70 thousand square kilometers a year. The global desertification has reached 36 million square kilometers, accounting for 1/4 of the entire Earth's land area,

15. which is equivalent to the sum of the land area of Russia, Canada, China and the United States. Throughout the world, the economic losses caused by the desertification has reached 42 billion dollars each year.

17. In China China is one of the countries which is the most seriously affected by desertification. The areas of desert, Gobi desert and desertification land in China are about 1.7397

18. million square kilometers, the part of modern desertification land caused by human activities is about 370,000 square kilometers, sand desertification caused direct economic losses is more than 54 billion yuan each year.

19. Desertification in China are mainly distributed in Xinjiang and Inner Mongolia, Tibet, Qinghai, Gansu provinces.

22. The cause of desertification 1. Abnormal climate changing 2. Unreasonable land clearing 3. Overgrazing 4. Unreasonable dredging and tree felling 5. Water resources wasting

23. The harm of desertification 1. deteriorating the ecological environment, affecting people's lives, threatening human health.

24. 2. Directly affecting agriculture, production and life 3. Causing significant economic losses, and impeding economic development 4. Exacerbating poverty level

25. Measures 1. Wind sheltering and sand fixation 2. Treating plants, expanding the proportion of grass, building protection system

26. 3. Rational developing and utilizing of water resources 4. Controlling the land reclamation, protecting vegetation, non abusing deforestation

27. 5. Improving the protection of the legal system, deepening the prevention publicity and education. 6. Establishing a national desertification prevention and control team.

28. 7. learning the advanced experience about sand control from foreign countries.

29. Sahara It is the world's largest desert, located in the south of the Atlas Mountains and the Mediterranean, west from the Atlantic Coast,

30. east to the Red Sea coast, across the continent northern, up to 5600 km from east to west, north to south width of 1600 km, the area of

31. approximately 9.6 million square kilometers, accounting for 32% of the total area in Africa.

54. Governing desert is a long way to go. Need our unremitting efforts!