DESERTIFICATION - Sahel

Question 1

What physical factors lead to desertification in the Sahel?

Answer 1

• Semi-arid: 300-600mm.
• High temperatures increase evaporation and dries the land, making it more vulnerable to soil erosion.
• Has been suffering from drought since the 1980s.
• Seasonal variation in rainfall - most rain falls between June and September.
• Rainfall is often heavy and leads to flooding since it can not infiltrate through the hard ground. This washes away nutrients and uproots vegetation.

Question 2

What human factors cause drought in the Sahel?

Answer 2

• There is civil war in Ethiopia, Eritrea and Somalia. This leads to desertification becasue it leads to an increase in use of marginal land as people are displaced. This increases soil exhaustion. The movement of refugees also causes desertification.
• The nomadic population is now settling into a sedentary lifestyle. This leads to overcultivation, which leads to infertility, which leads to decreased soil cover and increased soil erosion.
• 135 million inhabitants and a high fertility rate in its 10 countries which averages at 5.6. This population pressure leads to an increase in use of marginal land and an increase in overcultivation.

Question 3

How will people be affected by desertification in the Sahel?

Answer 3

• The Sahel now extends for 3 million squared km.
• Agricultural production will decrease, by 2050, from anywhere between 13 percent in Burkina Faso to 50 percent in Sudan.
• This leads to poverty in the mainly rural communities than depend on farming for their livelihoods.
• There is migration away from countries such as Chad, for example, which has a -3.45 migrants / every 1,000. These people often emigrate because they have lost their livelihoods, as aforementioned.
• Periods of low rainfall in 1968-1974 and 1979-1984, mixed with decreased productivity due to desertification, caused an estimated 100,000 drought-related deaths.
• Leaves people vulnerable to other natural disasters. In 2004 in Niger, a swarm of locusts destroyed crops.

Question 4

What environmental problems were caused due to desertification?

Answer 4

• There is decreased biodiversity. The only vegetation in the Sahel is xerophytic (drought resistant) shrubs and grasses.
• Desertification leads to more desertification. As the soil becomes more exposed, it can not support as much vegetation. This exposes it even further and causes soil erosion, and so on.

Question 5

How is Oxfam attempting to lessen the effects of desertification in the Sahel?

Answer 5

• Cash for work schemes - Oxfam employs local people to work for them in return for food vouchers.
• Destocking programmes reduce the number of livestock by paying owners a fair price for some that are healthy. This allows them to buy feed for the remaining animals. This is useful because it also reduces overgrazing as well as increasing the prosperity of farmers.
• Water points are constructed, which helps to develop a more efficient irrigation system.

Question 6

How do bunds decrease desertification in the Sahel?

Answer 6

• The sub-Saharan governments are providing logistical support so that bunds can be adopted on a larger scale.
• Stone bunds are strones that are placed on slopes which slow down surface runoff and allow it to infiltrate into the ground.
• It prevents soil erosion from flooding because it protects the soil and eroded the rock instead.
• Bunds also lower soil temperature, so that it is less dry and less evaporation takes place.

Question 7

How is afforestation being used to prevent desertification in the Sahel?

Answer 7

• It has been planned to build a ‘great green wall’ between the Sahara and the Sahel.
• This scheme was developed by the African Union.
• 11 states near the Sahara have created the Panafrican Agency of the Great Green Wall.
• This prevents desertification because planting trees increases cover of the land. This decreases soil temperature and decreases rate of evaporation. It also protects the soil from erosion from heavy rainfall, and creates a nutrient cycle.