Desertification Causes.

Presentation on theme: "Desertification Causes."— Presentation transcript:

1 Desertification Causes

2 Desertification – the problem
Nine-hundred million people in about 100 countries are at risk from desertification Desertification has degraded 73% of the world's rangeland By 1973, the drought that began in 1968 in the Sahel of West Africa and the land-use practices there had caused the deaths of more than 100,000 people and 12 million cattle, as well as the disruption of social organizations from villages to the national level.

3 中國戈壁沙灘向南蠶食綠地 戈壁灘緩慢但持續地向東南方向蠶食擴張
由於西北部的戈壁沙灘逐步向東南侵襲，中國內地面臨日益頻繁和嚴重的沙暴氣候。中國政府為此在過去一年里設法改進對風沙的長期預報技術和水平。 風沙南下 漫天的風沙會打亂正常生活，空氣中彌漫著沙塵，幾乎可以使人窒息。 在中國北方，人們對大風沙和沙暴天氣已經見怪不怪了。中國媒體去年春天就報道了13次沙暴襲擊的消息。 但現在，生活在河流湖泊眾多的南方的人們，也開始嚐到風沙的滋味。

4 Climatic factors for desertification

5 Climatic factors for desertification

6 Climatic factors for desertification

7 Climatic factors for desertification

8 Climatic factors for desertification
In Lebanon, 80-90% of rain falls between Nov and Mar Only 5% of rain comes in summer

9 Climatic factors for desertification
LONG PERIOD OF DRYNESS

10 Human factors for desertification

11 Human factors for desertification

12 Human factors for desertification

13 Human factors for desertification
INTENSIVE FARMING

14 Human factors for desertification
Infertile soil

15 Human factors for desertification
PASTURE

16 Human factors for desertification
scrub

17 Human factors for desertification

18 Human factors for desertification
Soil erosion

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