2. 
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land degradation in arid, semi-arid and dry subhumid areas resulting from various factors,
including climate variation and human activities"
(UNCCD 1995).
Almost half of the land surface, about 6.45
billion hectors is dry lands, One billion of these
hectors are real deserts such as the Sahara.
Desertification is worse in places like Africa and
Asia

3. World desertification map

4. Causes of Desertification
• There are 4 main factors in desertification
• Drought
• Over grazing
•Over cultivation
• Trees used for fuel and shelter

5. Drought 
Climatic fluctuations 

6. desertification
climate
humans
animals

7. Drought
A long period without rainfall
causes crops to die
lack of food
may have to move to find food

8. Causes of Desertification
Overgrazing –
too many animals grazing on the land
animals eat all the vegetation
vegetation fails to grow
soil is exposed to rain and wind
soil is washed or blown away.
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9. Overgrazing
too many animals grazing on the land
animals eat all the vegetation
vegetation fails to grow
soil is exposed to rain and wind
soil is washed or blown away.

10. 
Overcultivation –
◦ many crops being grown on the land year after year,
◦ no rotation of crops,
◦ crops take all the nutrients from the soil,
◦ the soil becomes infertile and nothing can grow.
◦ Because there are no crops to protect the soil the soil is
again easily eroded by the wind and rain
.

11. Removal of trees for fuel and shelter –
There are few trees in the desert and their roots
hold the soil together.
When the trees are removed for firewood or to
build shelter the roots die and the soil becomes
loose.
Yet again this means the soil can be easily blown or
washed away.

12. 
Drought: low rainfall since
1968.

Soils become dry and there is
no water left in wells.

Trees die, grass withers and is
replaced by poor desert scrub.

Crops fail and cattle feed on
poor pasture.
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Less roots to protect the
topsoil, less humus; soils
become more sandy and dry.
Wind erosion removes the soil,
causing dust storms, leaving
bare rock.

13. Population is high and
increasing fast.

To increase food supplies
more crops are grown and
more cattle kept leading to
over-cultivation and overgrazing.

Yields decline and cattle are
undernourished and die.

Demand increases for water as
population grows.
Trees are cut down for fuel
supplies. Called deforation.

Less vegetation; more dry, 
bare soil; more wind erosion.


14. Short Term Solutions
 Refugee Camps
 Medical Aid
 Food and Clothing Aid
Long Term Solutions

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Fence off areas to prevent animals grazing
there
Introduce drought resistant crops e.g. millet
Plant trees and bushes to provide cover for
soil and stop it being blown or washed away
Rotate crops and water them using irrigation
techniques
Build stone walls to collect moisture

15. Any factor that leads to the following is considered a desertification factor:
“Removal of vegetation”
“Removal of top fertile soil and reduction in biological productivity of soil”
„ Depletion of surface and ground water resources”

16. 
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Estimates of percentage of human actions
causing:
desertification are: overgrazing (35%),
deforestation,(30%), other agricultural
activities (28%), overexploitation
of fuel wood (7%), and bioindustrial activities
(1%) (Cullet).Human impacts can exacerbate
but not initiate desertification.

18. Food and water
shortages lead to
malnutrition,
famine, disease and
high death rates.


19. Loss of ecological stability.
Loss of biodiversity.
Reduction in carbon sink capability and their
effects on climate.
Floods, drought and related losses.
Damages to watershed
Soil erosion.
Silting up of reservoirs.
Desertification and Drought.
Changes in hydrological regime.
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20. Crop
productio
n
Drought
Unsustainabili
ty
Land
degradatio
n
Desertification
Poverty
Biodiversit
y
Change
in land
use
Migrations
Abandonme
nt

21. The soil becomes unusable
Nutrients in the soil can be
removed by wind or water.
Vegetation is lacked or damaged
Loosened soil may bury plants or
leave their roots exposed and
overgrazing might make
different plats extinct .
Lack of sales for some countries
Countries that rely on crops
being sold cannot make
anything off of them if the soil
isn‟t fertile enough to produce
them.
Food loss/ famine
The soil cannot produce food so
people cannot eat. Poor
countries that rely on this food
source may result in a famine.
People near affected areas
Desertification can cause
flooding, poor water quality,
dust storms, and pollution. All
of these effects can hurt
people living near an affected
region

22. In the short-term, provide food aid and water supplies to
prevent suffering.

Improve water supplies by building large reservoirs and
drilling deeper wells.

Conserve water in local small-scale schemes eg „magic
stones‟ in Burkino Faso.

Encourage sustainable farming practices (using locally-made
tools, not tractors).

Provide drought-resistant seed such as millet (northern
Nigeria). GM crops.

Tree planting schemes to reduce soil erosion (Mauritania).

International action to reduce the causes of global warming.


23. Nov 1992
Nov 1998
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Before and after
animals have
overgrazed and
trampled the
savanna.
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