“Desertification
is the degradation of drylands. It involves the loss of biological or economic
productivity and complexity in croplands, pastures, and woodlands. It is due
mainly to climate variability and unsustainable human activities. Seventy
percent of the world's drylands are degraded.
Desertification is
considered a major global environmental issue largely because of the link
between dryland degradation and food production. If desertification is not
stopped and reversed, food yields in many affected areas will decline.
Malnutrition, starvation, and ultimately famine may result.“
United Nations Secretariat of the
Convention to Combat Desertification
“Desertification
threatens nearly one quarter of the land surface of the globe. The
environmental impacts of desertification include a reduction in crop yields, a
loss of plants and a deterioration in the quality of plant foodstuffs available
to humans and animals. “
The Guardian newspaper, Desertification
special report, The Arid Expansion
It is important to underline that desertification [E1] [E2] [E3] [E4] [E5] [I1] [I2] [F1] [F2] [F3] [ES1] [ES2] is a big problem for land degradation but also
for food production whereby for people who live in that lands.
It seems that in many country droughts and famines
are not sudden natural disasters. Nor are they simply caused by lack of
rainfall. They are the end-results of a long deterioration in the ability of the
country to feed itself, perhaps a decline caused largely by mistakes and
mismanagement - both inside and outside that land.
·
39%
world surface affects desertification
·
250
millions people live in arid or semi-arid lands
·
more
than 100 countries in the world
·
costs
for desertification amount to 45 thousand millions dollars/year
·
70%
agriculture arid lands have yet been deteriorated
·
decrease
of food productions: 12 millions hectares/year lost
·
decrease
of biodiversity
Degradation begins in limited lands and
proceeds in alternative periods, increases during arid climate and regresses in
wet periods. It could be a mistake to consider the phenomenon only in a final
moment, it results from the arrangement of many complicated processes:
- soil erosion;
- increase of
salinity of soil;
- reduction of vegetable cover soil;
- variation of environmental hydrology;
- climate variation;
Desertification became well known in the 1930, when
parts of the Great Plains in the United States turned into the "Dust Bowl" as a result of drought and poor practices in
farming, although the term itself was not used until almost 1950. During the
dust bowl period, millions of people were forced to abandon their farms and
livelihoods. Greatly improved methods of agriculture and land and water
management in the Great Plains have prevented that disaster from recurring, but
desertification presently affects millions of people in almost every
continent.
Desertification is widespread in many areas of China.
The populations of rural areas have increased since 1949 for political reasons
as more people have settled there. While there has been an increase in
livestock, the land available for grazing has decreased. Also the importing of
European cattle such as Friesian and Simmental, which have higher food intakes,
has made things worse.
Activity One: Defining
Desertification
The purpose of this activity is to give students an
understanding of the complexity of defining the issue of desertification.
Share the following
background information with your students:
-
Deserts occur where
evaporation greatly exceeds the rainfall
-
More than one-third
of Earth is already classified as arid or semiarid, meaning that rain can be
extremely infrequent in those locations.
-
Furthermore, there is
a disturbing trend toward desertification, in which existing grasslands and
other ecosystems change into dry wastelands.
1.
Divide the class into
pairs. Each group should collect at least five important facts about
desertification process. Tell students that they are
going to research deserts and desertification to find out if they think the
trend toward desertification can be avoided or controlled. Research will be
conduct on materials provided by the teacher.
2.
Invite groups to use the
materials to chart on blank world maps areas of the world that are currently
prone to desertification.
