Transcript Combating Desertific..

Combating Desertification
How far is desertification a feedback to
human’s misuse of the natural resources in the
semi-arid regions?
Misuse – in an unsustainable way

-
What resources?
Land
Water
Energy resources
Results: demands exceeding the carrying capacity
Misuse of the Land Resources 1




From pastoralism to sedentary cultivation
& grazing in rangelands
Desertification sets in
About 65% of dryland areas are rangelands
Some suited to sustainable grazing than
crop production
Results: inadequate fallowing for recovery
Misuse of the Land Resources 2


From free mobility to restricted movements
Desertification sets in
Results: lower flexibility & adjustment of
economic activity to meet disturbances and stress
Misuse of the Land Resources 3


From full control to threat of long-term
security
loss of incentive for
maintaining
environmentally
sustainable practices
Results: Desertification sets in – vicious cycle!
Misuse of the Water Resources 1



From smaller households to large
population
Great need to increase in food production
Large-scale irrigation, tapping underground
water environmental crises
Misuse of the Water Resources 2

Environmental crises
e.g. water-logging & salinization, water
pollution, eutrophication,
over-exploitation of
groundwater aquifers
Results: degrading productivity of the land
Misuse of the Energy Resources 1



Destruction of vegetation in arid regions
Often for fuelwood / firewood
Leading to unprotected land
Results: Land degradation
Desertification –
other factors?
Other than human activities?
Desertificaton - Definition

a process of turning the productive land into desert

a land degradation process that involves a continuum
of change, from slight to very severe degradation of
the plant and soil resource, and is due to human
activities.

is also a situation on the desert expansion. That means desert
is continuously expanding to the surrounding area.
Desertification
Human factors
High pop.
+
Climatic change
Poor / poverty
Impropriate
irrigation
-salinization
Over grazing
Deforestation
Global
warming
Over cropping
↓ Soil fertility; soil degradation & Soil aridity
∴infiltration >E underground water table rises salinization
Less PPT
What can we draw?
“If the climatic factors are said to be the
main causes of desertification, then human
activities are going to intensify it.”
Desertification
& Climate Change
They are interlinked!
Desertification & Climate Change

Long-term climate change (aridity)

Global warming  rising temp  lower soil moisture
hinder condensation & rainfall  drop of water table 
further drop of soil moisture  loss of vegetation cover
(protection) loss of organic matters less cohesive soil 
easy erosion by wind & water  desertification climate
change  land degradation  loss of vegetation  higher
CO2 emissions global warming  lower evaporanspiration
 lower air humidity  less & infrequent rainfall …..

Temporary / high magnitude drought periods
in semi-arid areas
Effects of
desertification
Atmosphere
Hydrosphere
Lithosphere
Biosphere
-local climate
-water cycle
-loss of arable
breaks down
salinization
-extinction of
plants &
animals
↓PPT
drought
-macro climate
-land intensify the
soil erosion
global warming
Upset the balance of ecosystem
-↓biodiversity
Effects
Atmosphere
1) Micro
(i)↓PPT+↑T° ↑T in day time &↓ T in night
time↑ET/reflection ↑diurnal range of T°
(ii) ↑wind speed  ∵no veg cover / shelter
(iii) ↓relative humidity
2) Macro
(i)Global warming
(ii)Sandstormexpanding of desert
Effects
Lithosphere
1)loss of arable land
soil texture change to sandy  ↓cohesive
power (cannot hold water) not suitable for veg
growth
2)intensify the soil erosion
1.↑ deforestationno root to bind the soil
 ↑ soil erosion↑ silting
Effects
Hydrosphere
1)Water cycle breaks down
∵↓PPT & ↑ evaporation(∵ no shelter)
 rivers and wells dried up
Biosphere
1)lower the bio-diversity
∵↓PPT & unevenly dis.+deforestation
scattered veg. (veg. Is shorter, few
species, less luxuriant)extinction
Effects
Others
1)lower the income
∵PPT ↓  crops productivity ↓
2)use a large amt of $ for soil protection & recovery
(i.e. UNCED US$1,100 m per yr to recover the
deserted land)
What are the way out?
Between LDCs & MDCs….
How to solve – In LDCs
1. Control the pop. growth / natural increase by
using family planning, in order to decrease the
land use capacity
2. The number of grazing and the rate of
cultivation should not over the carrying
capacity of land
How to solve – In LDCs
3. improve farming & grazing methods, to check
reduce soil erosion and salinization
i) suitable timing and amount to carry out irrigation
plant the halophytes (which can adapt salty &
droughted soil) e.g. Chenopodiaceae
ii)sufficient fallowing period
animal welfare (e.g. Kenya)
How to solve – In LDCs
4. Legislation: ban the deforestation and over
grazing, etc., in order to balance the ecosystem of
desert.
5. Afforestation i.e. wind break trees & drought
resistant plants
6. Stone lines e.g. in Burkina Faso
7. Building reservoir and canal
e.g, The Indira Gandhi Canal
How to solve – In MDCs
1) international aid (e.g. Green Peace)
technology, low interest rate of loan &
education
2) scientific research
e.g World Association of Soil and Water
Conservation (WASWC)
How to solve – In MDCs
Both citizens in MDCs & LDCs have the
responsibility.
i) Don’t buy valuable halophytes (e.g. Fat Choi)
ii) 5R(reuse, reduce, renew, recycle, rethink)
iii) Fund raising
Effectiveness?
LDCs
1)Money? LDCs are so poor
2)International aid? lack of technology,
efficient farming skill
& low education
3)Attitude? X family planning
Effectiveness?
MDCs
MDCs
1) Exploitation? try to get more raw materials
& resources from LDCs
2) Human behaviour?? rapid ↑in living
standard & large amt
of wastes are produced
Remarks
The Recent Philosophy……
Remarks: “bottom-up approach”

~ drawing local communities to help:
(1) planning, decision-making & implementation
(2) empower those people who are most directly affected by
desertification / those depend most on the land for their livelihood,
to become the initiators of projects
(3) enable local communities affected by these problems to understand
properly the issues
*Take courage in formulating their unique solutions to the problems
within their particular environmental & socio-economic conditions