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- Sahel most seriously affected region for desertification in the world

-  semi-arid zone south of the Sahara Deser, rainfall variable and unreliable

. Four main human causes of desertification identified in the Sahel: - Over cultivation - Overgrazing - Deforestation  - Mismanagement of irrigation.

- The political instability and colonial legacy  not helped 

- . The rainfall has dropped below average almost every year since 1970. This lack of precipitation dries the soil and cracks it.

- Vegetation unable to grow so dies and leaves the soil exposed, causing the soil to lose structure



- Overgrazing =The use of chemical fertilisers

Global warming and lack of rainfall

- Climate feedback


DESERTIFICATION CASE STUDY: THE SAHEL - SENEGAL Causes of desertification: Overgrazing

- Overgrazing typically increases soil erosion.

- Reduction in soil depth, soil organic matter, and soil fertility impair the land's future natural and agricultural productivity.

- Native plant grass species, both individual bunch grasses and in grasslands, are especially vulnerable.

- Occurs when plants are overly exposed to grazing of animals for extended periods of time.

- Caused by livestock in poorly managed agricultural systems.

- It increases soil erosion, by reducing the depth, organic matter and fertility of the soil.


DESERTIFICATION CASE STUDY: THE SAHEL - SENEGAL Causes of desertification: The use of chemical fertilisers

- Soil fertility can sometimes be mitigated by applying the appropriate lime and organic fertilizers.

- However, the loss of soil depth and organic matter takes centuries to correct.

- Their loss is critical in determining the soil's water-holding capacity and how well pasture plants do during dry weather.

- Causes the soil to have a nutrient imbalance because chemical fertilisers are highly concentrated.

- They kill microorganisms living in the soil.

- The fertilisers can contaminate water sources.


DESERTIFICATION CASE STUDY: THE SAHEL - SENEGAL Causes of desertification: Global warming and lack of rainfall

- As temperatures rise, land surface warms so moisture from the soil evaporates.

- Decreased rainfall in Senegal due to climate change means vegetation harder to grow, less shelter of the soil creating a positive feedback loop.


DESERTIFICATION CASE STUDY: THE SAHEL - SENEGAL Causes of desertification: Climate feedback

- Adding dust and sand into the atmosphere is  one of the ways that desertification can affect the climate.

- Dust particles in the atmosphere can scatter incoming radiation from the sun, reducing warming locally at the surface, but increasing it in the air above.

- They can also affect the formation and lifetimes of clouds, potentially making rainfall less likely and thus reducing moisture in an already dry area.

- Soils are a very important store of carbon. The top two metres of soil in global drylands.l, dry soils are more likely to be net emitters of CO2. So as soils become arider, they will tend to be less able to take in carbon from the atmosphere, and thus will contribute to climate change

- . Other forms of degradation also generally release CO2 into the atmosphere, such as deforestation, overgrazing – by stripping the land of vegetation – and wildfires.



-Almost no more trees, and the grass does not grow anymore, so further away to find grazing for our cattle

- Many farmers in Senegal have had their livelihoods ruined due to drought and soil erosion

- Young people  forced to leave their villages in search of jobs and a better quality of life

- Senegal’s agriculture industry occupies roughly 70% of the country’s working population and contributes 15% of the GDP

- Senegal has experienced a food deficit and become reliant upon aid and imported food.



- Acacia tree planting

- The Great Green Wall


DESERTIFICATION CASE STUDY: THE SAHEL - SENEGAL Solutions to desertification Acacia tree planting

- Acacia trees have been grown to help combat desertification in Senegal as they also provide socio-economic benefits.

- From 2004 to 2007, FAO, in partnership with the Senegalese forestry service, provided seeds and seedlings and taught the women in the village how to sow and plant the Acacia trees as well as how to extract and market the gum they produce.

- They feed the soil by capturing nitrogen that restores fertility and provides a shelter for crops.


DESERTIFICATION CASE STUDY: THE SAHEL - SENEGAL Solutions to desertification The Great Green Wall

- The goal of the project is to plant a wall of trees, 4,300 miles long and 9 miles wide, across the African continent, from Senegal to Djibouti.

- The Great Green Wall has received a total of 1.8 billion dollars from the World Bank and another 108 million dollars from the Global Environment Facility Senegal is currently the furthest along with the Great Green Wall.

- They've planted roughly 50,000 acres of trees in addition to protecting existing trees.


DESERTIFICATION CASE STUDY: THE SAHEL - SENEGAL Solutions to desertification: Have they been successful?

 Acacia tree planting:

-  it has been extremely successful because the environment benefitting from the trees + the people

- The families can have a sustainable income that doesn’t rely on overgrazing and it is sustainable without damaging the environment

-  A total of 44 villages have benefited from the Acacia project in Senegal so far 523 people, mainly women and youth, have been trained in sustainable forest management and restoration, as well as forest products and business development.

- 4 500 hectares of degraded land have been restored and wildlife is being reintroduced in a community-based nature reserve in Koyli-Alpha


The Great Green Wall:

-  protect a lot of the country from the dust carried over from the desert

- However, large chunks of the proposed wall were uninhabited so no one would be there to tend to the saplings.

- Almost 80% of all trees planted in Africa since 1978 have died