Desertification

• Desertification is when land on the edges of deserts becomes desert-like. The Sahel, on the southern edge of the Sahara, is a well-known example.
• Physical causes include unreliable rainfall and long droughts. Sinking dry air near 30 degrees north and south helps to explain where dry lands lie.
• Human causes include overgrazing, over-cultivation with no fallow period, and cutting trees for fuel wood. Each leaves the soil bare, so wind and rain erode it.
• A typical chain: the population and its herds grow, more animals graze, plants are stripped, bare soil is eroded, and the land becomes desert-like.
• Strategies include tree planting, stone lines, drought-tolerant crops and solar cookers, often run by NGOs with local people.
• International action includes the Great Green Wall, an African-led project to restore land across the Sahel.

Desertification

Land on the edge of a desert becoming desert-like.

Sahel

The dry zone on the southern edge of the Sahara.

Overgrazing

Too many animals eating the plants, so the plants cannot grow back.

Fuel wood

Wood cut for cooking and heating.

Drought-tolerant crops

Crops that can survive with little water.

NGO

A non-governmental organisation: a charity or group that works to help people and is independent of government.

Stone lines

Rows of stones that slow runoff and trap soil on slopes.

• Saying desertification is only natural. People play a large part through grazing, farming and cutting trees.
• Thinking the vulnerable areas form a neat band. They are on the edges of deserts and dry lands in several parts of the world.
• Writing 'farming' or 'roads' alone as a cause. Say how the activity damages the land, such as ploughing too often without rest.
• Thinking cheap, local materials mean a scheme is poor or unsustainable. Simple schemes are often easy to run and repair.

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