Deserts And Desertification The Causes ,Consequences And Challenges

WERI FOUNDATION

1. Water and Energy Relief International 1
Desertification comes about by a complex
interaction between the natural environment and
human activities. The cause may vary from region to
region on account of economic conditions,
population pressure, agricultural practices, and
politics.
Human activities that destroys surface vegetation,
degrades soil structure and fertility, impedes water
infiltration, and causes soil drying promotes
desertification. This is especially true for the fragile
transition zone between arid and semiarid land where
human activity has stretched the ecosystem to its
limit causing expansion of deserts.
Desertification is a global problem occurring in
many places but is prevalent along the margins of
semiarid and arid lands in Asia, central Australia,
portions of North and South America, and Africa. A
world map prepared by the United States NRCS
shows just how widespread the problem is.
PHENOMENON OF DESERTIFICATION
United Nations Convention to Combat Desertification

2. Water and Energy Relief International 2
Desertification
Desertification is the expansion of dry lands due to poor
agricultural practices (e.g. overgrazing, degradation of soil fertility
and structure), improper soil moisture management, salinization
and erosion, forest removal, and climate change.
Desertification in Africa
Two common misconceptions prevail about desertification, that it
spreads from a desert core and drought is responsible.
Desertification spreads outward from any where excessive abuse
of the land occurs and far from any climatic desert. Droughts do
increase the possibility of desertification if the carrying capacity
of non-irrigated land is exceeded. Well-managed land can recover
from the effects of drought. Combining drought with land abuse
sets the stage for desertification.
United Nations Convention to Combat Desertification

3. Water and Energy Relief International 3
Cause of Desertification
Desertification comes about by a complex interaction between
the natural environment and human activities. The cause may
vary from region to region on account of economic conditions,
population pressure, agricultural practices, and politics. Human
activities that destroys surface vegetation, degrades soil
structure and fertility, impedes water infiltration, and causes
soil drying promotes desertification. This is especially true for
the fragile transition zone between arid and semiarid land
where human activity has stretched the ecosystem to its limit
causing expansion of deserts.
Population growth and its demand on agricultural resources
has promoted the desertification process. Over cultivation, for
example, causes declining soil fertility leading to falling crop
yields. Over use leads to crusting of exposed topsoil by rain
and sun that increases runoff, water erosion and gullying. Soil
drying promotes wind erosion and encroachment of sand
dunes on arable land.
United Nations Convention to Combat Desertification

4. Water and Energy Relief International 4
Overgrazing has several effects. It:
•Causes a decline in pasture vegetation and palatable grass species.
•Replaces perennials with short-lived annual species that do not hold
soil against erosion.
•Compacts soil under trampling hoofs.
•Destabilizes dunes when crest vegetation is eaten.
•Forest cutting for fuel wood has deforested large tracks of land in
Africa and Asia encouraging desertification.
Desertification around the world
The United Nations Conference on Desertification ranks
desertification hazard on the basis of a drop in agricultural
productivity:
None - less than 10%
Moderate - 10% to 25 %
High - 25% to 50%
Very high - more than 50%
Desertification is a global problem occurring in many places but is
prevalent along the margins of semiarid and arid lands in Asia, central
Australia, portions of North and South America, and Africa.
A world map prepared by the United States NRCS shows just how
widespread the problem is.

United Nations Convention to Combat Desertification

5. Water and Energy Relief International 5
DESERT AND DESERTIFICATION CHALLENGE AND
OPPORTUNUITIES
Africa has been significantly impacted by desertification. Almost
three quarters of Africa's agricultural drylands are already degraded to
some degree. The impact on desertification on the greatest number of
people occurs in Asia. Degraded regions include the sand dunes of
Syria, the eroded mountain slopes of Nepal, and the deforested and
overgrazed highlands of Laos.
The Northern Mediterranean region is the cradle of civilization and
has borne the effects of poor agricultural practices. Salinized, infertile
soils are the result of natural hazards e.g. droughts, floods and forest
fire, as well as overtilling and overgrazing. Soil degradation is high
through much of Central and Eastern Europe, and very high in some
areas, for example along the coast of the Adriatic Sea.
Poor irrigation practices and the unsustainable exploitation of water
resources are contributing to chemical pollution, soil salinization and
aquifer depletion. Nearly a quarter of the inhabitants of Latin America
and the Caribbean live below the poverty line fueling practices that
lead to land degradation. Erosion and water shortages are intensifying
in many East Caribbean islands.
United Nations Convention to Combat Desertification