Download P.3[PDF 416KB]

3
What
t
c
a
p
Im
ave?
tion H
a
c
i
f
i
t
r
e
s
e
D
Does
Because people, who live in drylands, depend on the ecosystem
services for their crops, livestock, commodities, fuel wood, etc.,
deterioration in ecosystem services by land degradation triggers
further degradation of their livelihood and well-being.
Both short-term and long-term climatic variations create
instability in the production of crops, forage, livestock, and also the
water supply. Once a dryland ecosystem is damaged, even the
removal of the cause cannot ensure full recovery of the ecosystem.
The well-being of the population is trapped in a vicious spiral of
decreased agricultural productivity and increased poverty.
Many African countries often have serious droughts. As the land
which is basis for food production is degraded, local people have
no choice but to exploit further natural resources such as forests
and water. This leads to further land degradation to create a
downward spiral.
▼ Consequences of Desertification
Undermining basis of
food production
Acceleration of poverty
Population concentration
in urban areas
Increased refugees
Loss of biodiversity
Impact on climate change
▼ Human Activities and Dryland Degradation
Human Factors: Political,
economic, socio-political
and scientific and technology
Political and
economic instability
Overgrazing and expansion
of cropped areas
▼ Population Affected by Desertification
Reduced
vegetation cover
Large-scale expansion
of irrigation
Increased soil erosion
Salinization
Global population 6.51 billion
People at risk to be affected
1 billion
Climatological
factors
People directly affected
250 million
Reduced
biological productivity
Climate change,
Drought
0
5
10
15
20
25
30
Source: UNCCD Fact Sheet（2005）
※ Population figures taken from ‘United
Nations World Population Prospects: The 2006 Revision.
60
65
70
Poverty, emigration,
and reduced human well-being
（100 million people）
Source: Millennium Ecosystem Assessment（2005）
▼ Linkages and Feedback Loops among Desertification, Global Climate Change and Biodiversity Loss
Desertification
Reduced carbon sequestration
into above- and below- ground
carbon reserves
Decreased plant and soil
organisms’ species diversity
The left hand side of the figure
shows the complex interaction
between desertification, climate
change and biodiversity loss.
Reduced primary production
and nutrient cycling
Desertification is not only the result
of climate change, but also
influences climate change by
Reduced soil conservation
reducing carbon sequestration of
vegetation and soil.
Increase in extreme
events（floods,
droughts, fires…）
Soil erosion
Diversity in vegetation in dryland
Reduced structural diversity
of vegetation cover and
diversity of microbial
species in soil crust
Reduced carbon
reserves and increased
CO2 emissions
ecosystem supports livestock and
wildlife as well as people through
provision of food and fuel. This
important function of biodiversity is
being damaged as a result of
desertification.
Loss of nutrients
and soil moisture
Climate change
Biodiversity loss
Increases and
reductions in species
abundances
Major services impacted
by biodiversity losses
Change in community
structure and diversity
Major components of biodiversity
involved in the linkages
Source: Millennium Ecosystem
Assessment（2005）