Case Study: Desertification | SL IB Geography Revision Notes 2019

Desertification in the Sahel

The Sahel is the transition zone between the Sahara Desert to the north and the wetter, more grassland savannas to the south
It stretches from the Atlantic Ocean to the Red Sea, a distance of 5 400 kilometres from west to east
The total area is roughly 3 million square kilometres and is home to around 260 million people

Growing at a rate of 3% per year, the population doubles every 20 years
The rate of population growth is higher than the rate of food output
The majority of the population relies on agriculture to meet food demands
Meeting those demands is difficult in a region with a high population and a warming climate

It receives approximately 200 to 600 mm of annual rainfall, which fluctuates annually
There are periods of intense rainfall in the Sahel, but they bring little benefit due to poor infiltration
Recurring droughts have caused famines in the region
Between 1970 and 2010, the region was notorious for hunger and malnutrition
Satellite imagery from the 1980s showed the Sahara expanding southward into the Sahel, but 10 years later, further images showed that the desert had retreated back to the north
Studies suggest that the Sahara fluctuates between expanding and retreating every few years
Despite no long-term trend in the Sahara Desert expanding, farmers are still under pressure to overgraze small areas of marginal land, thereby speeding up the process of desertification

Awaiting

Map showing extent of the Sahel region and reafforestation project

The causes of desertification in the Sahel can be divided into direct and indirect causes and are driven by:
- Changing climate (direct)
- Overgrazing (direct)
- Deforestation (direct)
- Poor agricultural practices (direct)
- Population pressures (indirect)
Despite the 3% growth in population each year, the Sahel region produces just 2% a year
This leads to intensive farming methods or farming on unstable land
People are becoming less active because of economic reasons or changes in the weather
Sedentary lifestyles are more degrading on the land due to increased water, food and resource consumption
This leads to over-cultivation, overgrazing, deforestation and overexploitation of water
Also, slash-and-burn farming has become more popular, which makes wind erosion worse by leaving behind dry, empty land

Dams, irrigation canals and wells were built during the 1980s and 1990s
- However, these wells were too small to combat drought, plus they provided a breeding ground for insects such as mosquitoes, which can carry disease
Countries in the Sahel region joined forces to form an alliance to combat severe drought and invested in high-yielding and drought-resistant crops
- This helped to stop soil degradation, desert encroachment whilst also providing jobs and promoting ecotourism
In Burkina Faso, Oxfam worked with farmers to improve the traditional stone wall, aiming to increase food production by using bund lines of stones across a slope to stop water and soil from running away
- This method preserves the topsoil and has improved farming and food production in the village
- They managed to increase millet, the staple crop in Burkina Faso, production by 50% on average
On a larger scale, the Great Green Wall is a plan to grow an 8 000-kilometre band of trees across 11 Sahel countries
- It is hoped that by 2030, 100 million hectares of degraded land will have been restored, which will help to decrease the impact of drought in the region
- Ethiopia has restored 15 million hectares