Desertification

What is desertification?

is the process by which land in dry areas becomes more like a desert: it loses its vegetation, its soil and its ability to grow crops.

It happens mostly on the , the edges of hot deserts, where rain is low and unreliable.

The Sahel is a strip of semi-arid land south of the Sahara, stretching across Africa from Senegal in the west to Sudan and Eritrea in the east. Severe droughts in the 1970s and 1980s caused famine there, and desertification has made millions of people's land less productive.

Key terms

Causes of desertification

Natural causes:

Climate change: less rain and higher temperatures, with more frequent and longer droughts.

Human causes, made worse by population growth:

Removal of fuel wood: trees and shrubs are cut for cooking and heating, leaving the soil bare.
too many animals eat the plants faster than they regrow, and trample the soil.
growing crops on the same land year after year uses up its nutrients.

Bare soil is then lost to : wind blows it away, and heavy storms wash it off.

Remember

Climate change, population growth, fuel wood, overgrazing, over-cultivation and soil erosion.

Key terms

Strategies to reduce desertification

Strategy	How it helps	Example in the Sahel
Water and soil management	Lines of stones along slopes slow runoff, so rain soaks in and soil stays put	Stone lines in Burkina Faso
Tree planting	Roots hold the soil; trees give shade, fodder and fuel	The Great Green Wall; farmers protecting tree shoots in Niger
	Simple, cheap methods that local people can build and repair	Zaï pits: small holes filled with manure, which catch rain around each plant

The Great Green Wall, launched by the African Union in 2007, is a belt of restored land about 8,000 km long, from Senegal to Djibouti. It aims to restore 100 million hectares by 2030.

Key terms

How successful are the strategies?

Zaï pits and stone lines in Burkina Faso have restored an estimated 200,000 to 300,000 hectares, raising crop yields. They are cheap and use local skills, but digging the pits is hard work.
In Niger, farmers protecting tree shoots that regrow from old roots has re-greened about 5 million hectares.
The Great Green Wall has restored some land, but progress is well behind its 2030 target, held back by a lack of money and by conflict in parts of the Sahel.

Judgement: small-scale methods run by local farmers have often worked best, because the people who use the land maintain them.

Exam practice

Plan your own answer first, then open the model answers to see what each level looks like.

6 marks · about 6 minutes

Explain the causes of desertification.

Explain means: Give the reasons why something happens, developing each point with "because" or "so".

Level 1 (Basic)· 2/6 marks (band 1–2)

Desertification is caused by climate change and too many people. Animals eat the plants.

Why this level: Correct causes named but not explained. To reach Level 2: explain how each cause turns land into desert, using "so" or "because".

Level 2 (Clear)· 4/6 marks (band 3–4)

Climate change brings less rain and higher temperatures, so droughts last longer and plants die. As the population grows, more trees are cut for fuel wood, and too many animals overgraze, removing the plants that hold the soil together. The bare soil is then eroded.

Why this level: Clear explanations of several causes. To reach Level 3: develop each further, include over-cultivation, and show how the causes link together to lead to soil erosion.

Level 3 (Detailed)· 6/6 marks (band 5–6)

Desertification has both natural and human causes. Climate change brings less rain and higher temperatures, with longer droughts, so plants struggle to survive. At the same time, population growth increases pressure on the land. More trees and shrubs are cut down for fuel wood; too many goats and cattle overgraze the remaining plants; and growing crops year after year without rest, called over-cultivation, uses up the soil's nutrients. All of these leave the soil bare, without roots to hold it together. It is then lost to erosion, blown away by the wind or washed off by heavy storms, so the land can no longer support plants, and becomes desert-like.

Why this level: Detailed, linked explanation of natural and human causes, all leading to soil erosion, with correct terms. This is Level 3.

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