water resources and climate change.pdf

7/27/2019 water resources and climate change.pdf

http://slidepdf.com/reader/full/water-resources-and-climate-changepdf 1/48

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Climate Change Impacts on

Water [email protected]

Professor Emeritus

CED, Trivandrum



2

CC affects

Precipitation (including extremes),Water vapour

Snow and land ice

Sea levelEvapotranspiration

Soil moisture

Runoff and river dischargePatterns of large-scale variability



3

CC also impacts systems and

sectorsEcosystems and biodiversity,

Agriculture and food security,

land use and forestry,Human health,

Water supply and sanitation,

Settlements and infrastructure,Economy: insurance, tourism,

industry, transportation.



4

Drivers of water usePopulation & Economic

Growth in developing nationsLifestyle changes, expanded

water supply systems and

expanding irrigation use arehighest users of all.



5

ASIA - 43 countries

Uneven Water distributionLarge areas under water stress

20 have renewable annual per capita water resources in excess

of 3,000 m3, 11 between 1,000 &

3,000 m3, 6 below 1,000 m3, butno data for the rest



6

ASIA (cont’d)

Large areas of arid & semi-arid lands.Humid and sub-humid areas water

scarcity/stress a major constraint for

sustainable development. Fast growingvery high population, Low development

levels & weak coping capacity, Climate

change expected to exacerbate the water

scarcity in Asia, along with multiple

socio-economic stresses.



7

Asian Freshwater resources

Decreasing trend of annualmean rainfall Russia, north-

east & north China, thecoastal arid plains of

Pakistan, parts of north-east

India, Indonesia, Philippines& some areas of Japan



8

ASIA WATER

Substantial interdecadalvariability in both the Indian and the

east Asian monsoons. Frequency of

more intense rainfall events in manyparts of Asia on the rise. So severe

floods, landslides, & debris & mud

flows. Fall in number of rainy days &total annual precipitation.



9

Rise in frequency & intensity of droughts

In Asia - due to rising temperatures,during the summer & normally drier

months - Rapid thawing of permafrost &

decreasing depth of frozen soils manycities & human settlements, Cause more

frequent landslides & degeneration of

some forest ecosystems,

Cause rise in lake water levels in the

permafrost region of Asia



10

Water shortages in India, Pakistan, Nepal

& Bangladesh, attribution to rapid

urbanisation & industrialisation,

population & inefficient water use.

Aggravated by changing climate &

adverse impacts on demand, supply &water quality.

The Brahmaputra –Ganges –Meghna &

Indus Basins water shortages result of actions of upstream riverside-dwellers in

storing water



11

Increasing water stress

falling production of rice, maizeand wheat in the past decades

in many parts of Asia.

Due partly to risingtemperatures, increasing

frequency of El Niño events &

reductions in number of rainy

days



12

Biodiversity

Gradual reduction in rainfall &resultant aridity aridity in central &

west Asia increased in recent years,

reduced the extent of grasslands &rise in barren ground & hence higher

moisture loss. Gradual fall in rain

during the growing season for grass.



13

CC Causes

Changes in seasonality & volume of discharge in river systems; rising

flooding risks in wet season & rising

possibility of water shortages in thedry season. Affects brackish-water

fisheries, seriously affect the

aquaculture industry &infrastructure, particularly in heavily

populated megadeltas.



14

Lower dry-season base flowsreduce of some species.

Saltwater intrusion of 10 –20 km

upstream in estuaries due to lower river runoff pushed further inland by

rising sea levels. Sea-level rises of

0.4 –1.0 m can induce saltwater intrusion 1 –3 km further inland



15

Higher snow and glacier melt,

rising snow lines, would be unfavourable

for downstream agriculture in several

countries of south and central Asia. Inthe medium term, climate-change-driven

enhanced snow or glacier melt will lead

to floods.



16

Rise in surface air temperature

a 27% decline in glacier area, a 10 –15%decline in frozen soil area, an increase in

flood and debris flow, and more severe

water shortages by 2050 compared to1961 –90. Gross per capita water

availability in India is projected to decline

from about 1,820 m3/yr in 2001 to as little

as 1,140 m3/yr in 2050, as a result of

population growth and CC causes..



17

Energy Changes in runoff could have a

significant effect on the power

output of hydropower-generatingcountries such as Tajikistan,

which is the third largest hydro-

electricity producer in the world.



18

Agr icu l ture Agricultural irrigation demand in arid and

semi-arid regions of Asia estimated to

increase by at least 10% for an increase

in temp. of 1°CEnhanced variability in hydrological

characteristics will be l ikely to continue

to affect grain supplies & food security inmany nations of Asia



19

Coastal areas

Especially heavilypopulated megadelta regions in south,

east and south-east Asia, expected to

face greatest risk of increased river andcoastal flooding. In southern and eastern

Asia, the interaction of CC with rapid

economic and population growth,

and migration from rural to urban areas,

is expected to affect development



20

Adaptation and adaptive capacity

In developing Asian countriescontinue to be limited by

various ecological, social &

economic, technical, institutional &political constraints. Water recycling

a sustainable approach towards

adaptation to climate change & canbe cost-effective in the long term.



21

Rate of melting of Asian glaciers

constant since at least the1960s-Exception: the central

Karakorum



22

World wide

Irrigation uses ~ 70% of totalwater withdrawals & adds to

more than 90% of consumptive water use (i.e.

water not available for reuse).

Irrigation gives ~40% of totalagricultural output.



23

Since 1960

Globally, irrigated land increasedapproximately linearly, @

roughly 2% p.a. from 140 millionha in 1961/63 to 270 million ha in

1997/99, i.e., about 18%

of today’s total cultivated land(Bruinsma, 2003).



24

India occupies over 3.0

million km2, with enormous

diversity of climate,landscape, geology, flora and

fauna.



25

According to National Water Policy

in the planning and operation of

systems, water allocation priorities

are broadly as: (i) drinking water, (ii)irrigation, (iii) hydropower, (iv)

ecology, (v) agro-industries and

non-agricultural industries,and (vi) navigation.



26

Indian river systemmore than 20 major rivers & several

tributaries.Annual precipitation = 4000 km3

(rain+snow).

Monsoon yield = 3000 km3.(SW monsoon yield from June to

Sept.)

Tamil Nadu receives only NE

(October and November) monsoon..



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India=3.29 million km2Population =1,027,015,247 persons

(Census 2001).

(i.e., 2.4% or 1/50th of world’s land; 15%

or 1/6th of world’s population; 1/25th of

world’s water resources)Indian livestock = 500 million, (20% of

world’s).

More than half are cattle-backbone of Indian agriculture. Total utilizable water

resources = 1086 km3.



28

GW resources of India (km3/year )Replenishable = 432

Domestic, industrial and other uses= 71

Available for irrigation= 361

Utilizable for irrigation= 325 (90%)

Total utilizable GW resource = 396



29

Kerala:

Area: 38,836 km2 ; Population: 31.8 million (Census,

2001)

Size of side of support square: 34 m; Population

density: 798/kmHighland, elevation >75.0m ; area: 18,696 km2 ; 48.14%

Midland, elevation 7.5-75.0m; area: 16218 km2;

41.76%

Coastal land, elevation <7.5 m; area: 3922 km2; 10.10%

Low coastal land: 2992 km2; 76.29%

High coastal land: 930 km2; 23.71%



30

Kerala- High landNatu ral fo rest:

Decrease in p lant species divers i ty-

consequent fall in animal species

divers i ty - increas ing dryness – higher

w ind and water erosion so i l loss

Soil and nutrients:

Loss of soil moisture due to extended

days of drought and severe showerydays – loss of soil and soil nutrients due

to intense rain water erosion



31

Kerala- High landAgrobiodiversity:

Exposure of cardamom, tea, coffee,

rubber and others to long warmer spells

and heavy rainy spells – both adverse for

these crops

Pests and vectors:

A jump in intensity of invasion- but

durations may decline



32

Kerala- High landHydro-power:

Bleak outlook- span of wet days decline

and so is base flow days- decline of days

reservoir staying at or near FRL – higher power demand due to rising demand for

air-conditioning for extended periods; for

pumping water from wells, irrigation anddrinking water supply schemes. Barren

land releases largrger sediment load



33

Kerala Midland

Agro-biodiversity: harmed due todrier soil and drier air-

decreasing latex yield in rubber

plantations- decreasinghomestead farm production –

decline in livestock farming andmilk production – decrease in

food crop farming and out put -



34

Kerala MidlandSoil and nutrients:

Decrease in nutrients and

increase in area under erodedsoils- extreme wet and dry

spells tend to erode top soiland nutrients



35

Kerala Midland

Agro-biodiversity:Decrease in yield from

rubber, coconut, arecanutfarms – decrease in soil

moisture and air moisture-

soil microbes change due to

physical changes in soil



36

Kerala Midland

Pests & vectors:Density will jump but duration

of activity may decline



37

Kerala Midland

Surface & ground water:Decline in the duration of base flow

in streams- aquifers get deeper-

increase in kwh/m3 of water lifted for use in farms, industry and homes.

Dissolved ion content in water may

go up due to decreasing dilution andhigher evaporation loss of soil

moisture



38

Kerala Coastal landSLR due to GHG

Salt water intrusion in river channels, coastal lagoons &

aquifers



39

Kerala Coastal land

GHG led SLR erodes beaches in

LCL- shoreline migrates

eastward – beach front property

and homes damaged- civicfacilities like coastal roads,

water supply lines, waste water

disposal and sanitation facilitiesdamaged- power standards &

supply system uprooted



40

Kerala Coastal land:

Salinity rise in soil moisture –Salination of aquifers

damages foundation of public

buildings and homes –domestic shaft well water

turns brackish - quality of public water supply sources

decline



41


Salinity intrusion intoaquifers- inlets and coastal

wetlands – wetland

ecosystems including paddyfields in LCL affected- plant

and machinery in themanufacturing units ruin by

salinity intrusions



42


fauna & flora slide into

environmental stress - due todisruptions unable to migrate

or re-establish



43

Wet lands of Kerala

Two Types:Natural (in CL) &constructed (in ML & HL) wetlands

Water in wetlands, river channels,

intra-costal water ways all suffer byhigher salinity, decreasing flow -

aquatic animal and plant life under

duress – many species may becomeextinct – water supply system &

sources suffer.



44

Impacts on Social Life:

Increasing violence and anarchy inthe society- Disruptions in civic life

and stress due to warmer

temperatures-Citizens more prone to

anger & violence.

New diseases: poor sanitation,

waterborne & contaminated water.



45



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PROPOSED SOLUTIONS

Hydro damsModified Irrigation

Residue return

Drainage of cropland

Wastewater treatment

DesalinisationGeothermal energy



47

PROPOSED SOLUTIONS

CO2 capture and storage

Bio-energy crops; Biomass electricity:Hydropower; Geothermal energy

Efficient Energy Use in buildings;

Land-use change & management,

Cropland management (water),

Cropland management (reduced tillage),

Afforestation/reforestation,

Avoided/reduced deforestation,Solid waste management; Wastewater

treatment; Unconventional oil.



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LET US ALL WORK FORNATIONAL WATER

SECURITY TO ONE ANDALL IN NEAR FUTURE.

THANK YOU VERY MUCH.

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