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DESERTIFICATION
What Desertification
VI.
Geography is desertification?
Land degradation (soil erosion, waterlogging,
salinization, land use change) in arid, semi-arid and
dry sub-humid areas resulting from various factors,
including climatic variations and human activities.
Linear dunes in the Sahara Desert
What causes desertification?
It is caused primarily by human activities and
climatic variations:
population growth: populations are
increasing as fast in arid lands as
elsewhere
overcultivation,
overgrazing,
deforestation,
poor irrigation
People takes too much from the soil and puts too
little back
Image of Sahelian mother and child
Environmental Issues | Page 10
Desertification
Geography 12
Why is desertification a problem?
Desertification is a problem because:
one-third of the earths land is arid or semi-arid
overall land degradation of various sorts is estimated to be causing an annual loss of 12 million
tons of grain output: almost half of all the grains output each year
some 250 million people live there, 100 countries are affected
more than 20% of the earth - home to 80 million people - is directly threatened by desertification.
Who and/or what does desertification affect?
Over 250 million people are directly affected by desertification. In addition, some one thousand million
(or one billion) people in over one hundred countries are at risk. These people include many of the world's
poorest, marginalized, most and politically weak citizens.
Are there any solutions?
At the local level, individuals and governments can help to reclaim and protect their lands.
In areas of sand dunes, covering the dunes with large boulders or petroleum will interrupt the
wind regime near the face of the dunes and prevent the sand from moving.
In areas where some water is available for irrigation, shrubs planted on the lower one-third of a
dune's windward side will stabilize the dune. This vegetation decreases the wind velocity near the
base of the dune and prevents much of the sand from moving.
More efficient use of existing water resources and control of salinization are effective other tools for
improving arid lands.
Use surface-water resources such as rain water harvesting or irrigating with seasonal runoff from
adjacent highlands.
Find and tap groundwater resources and to develop more effective ways of irrigating arid and
semiarid lands.
Research into proper crop rotation to protect the fragile soil, on understanding how sand-fixing
plants can be adapted to local environments, and on how grazing lands and water resources can
be developed effectively without being overused.
If we are to stop and reverse the degradation of arid and semiarid lands, we must understand how and why
the rates of climate change, population growth, and food production adversely affect these environments.
Environmental Issues | Page 11