Causes and consequences. Desertification Causes and consequences.

At the end of this lesson I will be able to: State what desertification is? Name a place that is experiencing desertification. Write two points (containing 3 bullet points each) on the causes of desertification. Examine 3 consequences of desesrtification. Describe 3 solutions to desertification.

Desertification is The gradual spread of the desert into agricultural land.

The Sahel experiences desertification. It borders on the Sahara Desert.

Causes of desertification. Drought This is insufficient precipitation. There is also high evaporation due to high temperatures and trade winds. Scientists believe droughts are becoming more severe due to climate change.

2. Human Activity Increased populations has seen increased demand for food leading land to be overworked and overgrazed. The destruction of the roots of plants by grazing animals and cutting down of shrubs and trees for firewood leaves soil exposed. Soil erosion occurs once the soil is exposed. i.e it blows away.

Goats, sheep and cattle overgrazing fragile pasture, Bakino Fasa in the Sahel.

Goats grazing fragile pasture in Chad

The Sahel is the name given to a 1,000-kilometre band of savannah in Africa south of the Sahara, stretching from Mauretania in the west to Eritrea on the Red Sea coast. The four driest periods in this relatively arid region were in 1913, 1972, 1983 and 1984. Three of these dry spells followed an eruption of Katmai in Alaska in 1912 and of El Chichon in Mexico in 1982.

The extended drought between 1970 and 1990 in the Sahel region claimed 250,000 lives and created 10 million refugees: it was one of the world’s biggest humanitarian disasters. All kinds of causes were evoked, including overgrazing, natural variability and industrial exhausts, but Professor Haywood and his colleagues think that volcanic eruptions also strongly influence the sea temperatures in the Atlantic, which are associated with Sahelian drought.

They simulated the impact of continued global warming into the future and found that only 11 of the 50 years between 2020 and 2070 would have negative Sahelian precipitation anomalies.

A new analysis of Africa's past and future climate shows that the Sahel region, which experienced catastrophic drought for decades until rains returned in the 1990s, could experience wetter monsoons for decades to come. However, drought across southern Africa is projected to intensify further. Scientists have linked this to changes in temperatures of the atlantic ocean( cooling ) indian ocean (warming)

What were our causes again? Drought

2. Human Activity

Wind Wind Human Activity Drought Soil become bare Population growth Evaporation Insufficient rain Climate change overgrazing Cutting down trees Human Activity Drought Soil become bare and exposed and blows away Wind Wind Desertification

Wind Wind Human Activity Drought Soil become bare Population growth Evaporation Insufficient rain Climate change overgrazing Cutting down trees Human Activity Drought Soil become bare and exposed and blows away Wind Wind Desertification

At the end of this lesson I will be able to: State what desertification is? Name a place that is experiencing desertification. Write two points (containing 3 bullet points each) on the causes of desertification. Examine 3 consequences of desesrtification. Describe 3 solutions to desertification.

What is a consequence? Something that happens as a result of something.

What is a consequence of desertification?

1. Loss of agricultural land. Millions of hectares of land has turned into desert. People don’t have any land to work. Livelihoods of millions is threatened.

2. Famine Loss of agricultural land means less food is produced. Less food when the population is growing has led to famine. Famin results in death E.g in Ethiopia.

3. Migration People leave the areas of desertification, Population rises in other areas. Overgrazing etc. occurs here causing desertification.

At the end of this lesson I will be able to: State what desertification is? Name a place that is experiencing desertification. Write two points (containing 3 bullet points each) on the causes of desertification. Examine 3 consequences of desesrtification. Describe 3 solutions to desertification.

Desertification Migration No land to farm Famine

Solution Irrigation Restrict grazing Drought resistant shrubs and plants

Solution to Desertification http://www.icrisat.org/newsroom/latest-news/happenings/happenings1431.htm

1. Irrigation This means bringing water from one area to places that don’t have any water. This allows previously unusable land to be used for agriculture. Solar powered pumps are now being used for irriagtion in the Sahel

2. Restricted Grazing Limits on the number of animals grazing and the types of animals grazing help preserve roots of plants. Plant keep the soil together. Soil less likely to be eroded.

3. Drought resistant plants Sorghum – drought and heat tolerant. Grass/grain crop for food, fodder, biofuel and alcohol. Easier to grow than grass for grazing and soil isn’t eroded. http://vimeo.com/20850064

What is desertification?

What causes it? Drought Human Activity

What are the consequences? No land Famine Migration

Solution Irrigation Less grazing Drought tolerant crops.

Regreening the Sahel

At the end of this lesson I will be able to: State what desertification is? Name a place that is experiencing desertification. Write two points (containing 3 bullet points each) on the causes of desertification. Examine 3 consequences of desesrtification. Describe 3 solutions to desertification.