combating desertification how far is desertification a feedback to human’s misuse of the natural...
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Combating DesertificationHow 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 cro
p 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
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
High pop. Poor / poverty
Climatic change
Over -cropping
Deforest- ation
Over -grazing
Global warming
Less PPT
↓ Soil fertility; soil degradation & Soil aridity
Human factors
+Impropriate irrigation
-salinization
∴infiltration >E underground water table rises salinization
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 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 desEffects of desertificationertification
Atmosphere
-local climate
↓PPT
drought
-macro climate
global warming
Hydrosphere
-water cycle
breaks down
Lithosphere
-loss of arable
salinization
-land intensify the
soil erosion
Biosphere
-extinction of plants & animals
-↓biodiversity
Upset the balance of ecosystem
EffectsAtmosphere1) 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)Sandstormexpanding of desert
EffectsLithosphere
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.↑ deforestationno root to bind the soil
↑ soil erosion↑ silting
EffectsHydrosphere1)Water cycle breaks down ↓∵ PPT & ↑ evaporation( no shelter)∵ rivers and wells dried up
Biosphere1)lower the bio-diversity ↓∵ PPT & unevenly dis.+deforestation scattered veg. (veg. Is shorter, few species, less luxuriant)extinction
Effects
Others1)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)
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?
LDCs1)Money? LDCs are so poor
2)International aid? lack of technology,
efficient farming skill
& low education
3)Attitude? X family planning
Effectiveness?
MDCs1) Exploitation? try to get more raw materials
& resources from LDCs
2) Human behaviour?? rapid ↑in living
standard & large amt
of wastes are produced
MDCs
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