2017
Research report
Ecology and Environment 1
The question of desertification in the sub-Saharan region
By: Laura Fuller
About Desertification
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Desertification is when a desert gradually spreads to the surrounding areas of semi desert.
It affects every continent apart from Antarctica
3.6 billion hectares of the worlds surfaced have been affected
Formerly productive land that has become a desert, often due to a combination of natural
factors, such as drought or human factors such as overgrazing
Desertification involves the destruction of ecosystems and habitats.
Land that was once marginal is turned into an unproductive wasteland – vegetation dies
and soil becomes exposed and eroded
300 million people in more than 100 countries are directly affected by desertification and
more are at risk.
Distribution of areas at risk
The most vulnerable area tend to be located on the margins of the hot deserts. The UN estimates
that roughly a third of the world’s land and surface is currently affected by desertification
Causes of Desertification
Human causes:
Over-cultivation intense farming on marginal land can reduce soil fertility and damage its structure
the lack of organic matter makes it crumbly and more likely to be blown away or washed away
Over-grazing marginal grassland has a sustainable capacity - the number of animals that can be
supported without causing any long term damage if this number is exceeded, the system becomes
unsustainable and the vegetation and soil deteriorates
Over-irrigation If land is over irrigated, salinisation can occur. Salinisation occurs when the water in
soils evaporates in high temperatures, drawing salts from the soil to the surface.This creates an
impermeable and infertile salty crust on the surface
Other human activities that can damage the soil and vegetation are road building, deforestation
and tourism
Population growth: More people need more food which puts pressure on the land
Deforestation: Tress are cut down for fuel and building. The loss of roots to hold the soil down
gives rise to erosion
War: Many sub-Saharan countries have suffered for years from civil war, where crops and animals
have been destroyed leading to famine
Physical causes:
Climate change and drought: This damages animal’s habitats and the soil in many areas. This also
leads to famine as crops die. Disease is prevalent due to poor water quality.
Rainfall is unpredictable and temperatures are high. When it does not rain the soil becomes dry as
evaporation is high. However when it does rain it washes the soil away
Soil erosion: Soil which is exposed can easily be removed by wind or water thus resulting in
desertification
Rainfall: Changing rainfall patterns rainfall has become less predictable and prolonged droughts
more common and therefore the soil is dry and more erodible.
Impacts of Desertification
Soil becomes less usable - The soil can be blown away by wind or washed away rain.
Nutrients in the soil can be removed by wind or water. Salt can build up in the soil which
makes it harder for plant growth. Vegetation is damaged - Loosened soil may bury plants or
leave their roots exposed. Also, when overgrazing occurs, plant species may be lost.
Food Loss - The soil is not suited for growing food; therefore the amount of food being
made will decline. If the population is growing, this will cause economic problems and
starvation.
Population
About 260 million people are thought to be living in the Sahel region
But the population is estimated to be doubling every 20 years there
The rate of population increase (3% a year) is greater than the increase in food production
(2% a year)
The more people mean more food is needed. This could lead to over-cultivation and over-
irrigation. This puts pressure on the land to be more productive
FOR EXAMPLE The Sahel
The Sahel stretches across the African continent through 9 countries
People who live in the Sahel are some of the most poorest in the world
It has a combination of low and unreliable rainfall and hot summer temperatures
Long droughts and serious famines are common
It is an area of 650 000 square km
Energy and fuel wood crisis
The people who live in the Sahel reply on wood for cooking therefore thousands of trees
are cut down
The tree canopy protects the soil from the sun as the sun will evaporate the moisture from
the soil leaving it dry and therefore it may be blown away
If trees are cut down, the roots will die and the soil will become erodible
Water supply
The Sahel suffers from an unreliable rainfall so droughts are common
Without water vegetation starts to die and the soil turns to dust therefore making it easier
for the wind to erode it
15.6 million people were affected by a drought in 2011-2012
Food supply
Nearly 20 million people are at risk of starvation
1/3 of children in Burkina Faso will not reach their full growth potential due to lack of food
Crop production is down by 26%
There is a 25% drop in agricultural production
Farming
It is estimated that up to 4 million hectares of land is now infested by locusts in South Africa
Crop production has reduced in 2012 by 26% when comparing to 2010
Livelihoods
15.6 million people were affected in the Sahel region by the 2011-2012 drought
There was migration to the cites to Europe and to the Mediterranean jungle
Management strategies/Solutions
External Aid: Oxfam launched an appeal to aid 1.8 million people with emergency
resources/help. They aimed to give food aid to people and emergency support
The Eden reforestation project: the replanting of trees will bind the soil together and
therefore soil erosion would decrease and soil fertility will increase, it also has created jobs
for 3500 villages worldwide. Over 1 million trees are being planted in Ethiopia’s rift valley.
The aim is to reduce poverty by employing local people to replant the trees. These trees
will not only bind the soil together and reduce soil erosion, but it will provide shade for the
ground/soil and therefore evapotranspiration will decrease
The great green wall involved planting a 15km wide and 7100km long tree belt to combat
desertification. It aims to tackle poverty as it provides jobs, decreases soil erosion and
maintains soil fertility. It provides fresh fruit and veg for locals and the community approves
of the project.
Diguettes: a line of stones which are laid along the contours. They act as a semipermeable barrier which allows water to slow down and allows nutrients to be deposited.
This was very successful as the community are involved and it encourages them to work
together.
Technology: drought resistant seed genetically modifies crops. It increases food supplies
and it is resistant against common diseases. It is expensive and it’s hard to change tradition
but it can cause harvest to double.
Appropriate technology: Warka water towers collects 25 gallons (100 litres) a day of
water. The Warka water towers catches condensation out of the air and water is collected
at the bottom. It can be built by locals and therefore is sustainable. They provide water for
people, animals and field. No electricity is needed. It is very successful as it is good for the
environment, it provides jobs for the locals and it saves them time walking to get water.