Agricultural Water Management - The Key To Food Security In A Changing World
-
Upload
international-water-management-institute-iwmi -
Category
Education
-
view
2.496 -
download
3
description
Transcript of Agricultural Water Management - The Key To Food Security In A Changing World
Agricultural Water Management: The Key to Food Security in a Changing World
David MoldenInternational Water Management Institute
Water Scarcity 2000
1/3 of the world’s population live in basins that have to deal with water scarcitySource: Comprehensive Assessment of Water Management in Agriculture, 2007
Other Water Pressures
Urbanization - Cities are projected to use 150% more water in 2025
Agriculture – Water fuels production increasesPopulation & Diet – food grain production
projected to increase by 100% by 2050Energy – Hydropower and biofuels compete for
water and landClimate Change – Shifting patterns of water
availability – potential yields decline in Africa
Drivers of Water Use
River basins closed – Colorado, Murray Darling, Yellow, Indus, Amu Darya ……… no additional water left
Groundwater overdraft – in agricultural breadbaskets
Fisheries – ocean and freshwater at a limit, aquaculture will become more prevalent
Livestock – limit on extent of grazing land, more will come from mixed and industrialized production
Limits – Reached or Breached
ASIA: High Numbers of Poor, AFRICA: High Percentage Poor
1.7M poor, 960M undernourished people (12/2008, FAO)
Policy Concerns
• Food self-sufficiency – increase food production to meet growing population needs (need more water)
• Save water from agriculture – to meet needs of growing cities and environment (less water for ag)
• Water to fight poverty (more water)
IS THERE ENOUGH WATER?
Will there be enough water?
More People – 6.5 to 9 billion people by 2050
More calories & more meat, fish, milk
More food production – need to double grain production by 2050
More water for food – if practices don’t change, double water needs
This equation doesn’t work – something has to change
Will there be enough water?More people – 6.5 to 9 billion people by 2050
More calories & more meat, fish, milkMore food production – need to double grain production by 2050
More water for food – if practices don’t change, water needs double
Something has to change
Based on IWMI WaterSim analysis for the CA
Today
Without Water Productivity Gains,
Crop ET doubles by 2050
2050
Water Use – Today and 2050
No Water Productivity Gains
Climate Change
Some areas will be wetter, others drier, more rainfall variability, all hotter
Source: Arnell, 2003.
Water Scarcity and Climate Change
Some areas wetter, some areas drier
Source: Comprehensive Assessment of Water Management in Agriculture, 2007.
Climate Change, Water, Agriculture3 Critical Concerns
Glacial Snowmelt – Himalayas, Andes, African HighlandsRising Sea Levels - River delta systems
Mekong, Egypt’s Nile DeltaClimate Variability – across
sub-Saharan Africa
Water implications of mitigation measures?
Biofuels Afforestation
SolutionsOlivia Molden
Water Management
Major Pathways to Meet Future Food & Water Demands
• Invest in rainfed agriculture• Invest in irrigation
– Improve productivity of existing systems– Expand irrigation
• Promote trade from highly productive to less productive regions
• Manage demand, consume and waste less
Consider the Full Range of Agricultural Water Management Options
Fish, Livestock, Crops, Ecosystem Services
1. Water to Fight Poverty –what is potential?
Where are the rural poor in SSA ?
Source: FAO, 2008: Water and Rural Poverty
Poverty reduction potential of AWM solutions across livelihood zones
Source: FAO, 2008: Water and Rural Poverty
FAO - SSA 245 Million 58% are rural poor
AWM Team - SSA
279 Million 65% are poor
AWM Team - India
220 Million 90% are poor
This Project (Gates funded Ag Water Management Solutions):65M rural poor livelihoods improved in 15 years
Who could benefit from Agricultural Water Management Solutions?
2. Transform water governance
• Poverty, hunger, gender inequality, and ecosystem degradation continue - not because of technical failings but because of political and institutional failings
• Water availability has changed, but our actions have not
• No blueprints - need to craft local solutions
Transition From To
Exploiting water resources Managing Demand
New allocations Reallocating water
Who is included and excluded
Safeguarding right to water
Developing groundwater Regulating groundwater
Institutions for single sectors
Institutional frameworks able to deal with cross sectoral issues
Manage as per design
Deal with uncertainty, adaptive manage for change, data, monitoring, feedback important
Form Coalitions
• Emerging interest of private sector
• Important to trigger policy change
Water storage mitigates variability
Source: World Bank data from ICOLD
But need to re-think water storage: role of groundwater “groundwater banking” and soil moisture.
And beyond: insurance, local trade
Cub
ic m
eter
s pe
r ca
pita
3. Water Storage – a safeguard against climate variability
4 43 7
46 128
7
140
6 248
6
325
5
472
9 615
0
0
1,0002,000
3,000
4,000
5,0006,000
7,000
Ke
nya
Eth
iopi
a
So
uth
Afr
ica
Th
aila
nd
Lao
s
Ch
ina Bra
zil
Au
stra
liaN
ort
hA
me
rica
MAKING STORAGE “SMARTER” –storage continuum
All of the above
Planting crops
Direct,Buckets, pumps
Dam outlets,pumps, off-take towers
Natural wetlands
Reservoirs
Ponds and Tanks
Aquifers
Soil Moisture
deep shallow
small large
SUBSURFACE SURFACE ACCESS
Increasing resilience Increasing resilienceIncr
easi
ng
cap
ital
co
sts
Incr
easi
ng
co
mp
lexi
ty o
f m
anag
emen
tIn
crea
sin
g e
nvi
ron
men
tal
and
so
cial
co
st
Boreholes,deep /shallow wells
4. Manage Water Demand
• Reducing withdrawals mitigates – half of India’s irrigation is from groundwater requiring pumps
• Put in place innovative incentives, allocation, pricing policies to curtail water demands
• Food waste is water waste
5. Grow more food per unit of water
Increase Water ProductivityPhysical Water Productivity – more crop per drop– Reduces water needsRange shows that there is considerable scope for
improvement– Wheat 500 to 2000 liters/kg– Beef 5000 to 20000 liters/kgIPCC – crop yields in SSA could decline by 50%, butComprehensive Assessment says could more than
double with investment and management
0
50
100
150
200
250
300
350
400
450
500N
umbe
r of p
ublic
ation
s
Year
Number of publications related to water productivity from 1990 to 2007(The result is from Google Scholar search using fixed term “water productivity” )
Opportunities in Rainfed Agriculture• Largest opportunities to build resilience and
improve water productivity are in rainfed landscapes – low water productivity, high poverty
• Technology– water harvesting, supplemental irrigation– Field water conservation to reduce
nonproductive evaporation– Improved nutrients – Drought resistance varieties
• Expand Policies to includeupgrading rainfed systems
Asia needs to feed an extra 1.5 billion people by 2050, with food needs projected to double.
Cannot rely on rainfed alone
Asia contains 70% of the world’s irrigated area
Important to do it right for:• Climate change• Food security• Environment
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Ch
ish
tian
su
b-d
iv.
Ma
hi-K
ad
ana
Na
chch
adu
wa
Mu
da
Ra
jan
ga
naya
Nile
De
lta
Ko
ura
ni B
aria
II
Su
nsa
ri M
ora
ng
Go
rgo
We
st G
an
dak
Ma
rch
wa
r Lift
Sa
ga
Big
Th
om
pso
n
Kh
ag
eri
Pa
nch
aka
nya
Fry
ing
pa
n
Ka
nka
i
Mo
gte
do
Sa
lda
na
Ko
ura
ni B
aria
I
Se
yha
n
Co
ella
RU
T
To
rre
on
Sa
lva
tierr
a M
odu
le**
Alto
Rio
Le
rma
*
Co
rta
zar M
od
ule
*
Sa
lva
tierr
a M
odu
le*
Me
ne
me
n
Imp
eria
l ID
Ma
nis
a
Sa
ma
ca
Trif
fa S
che
me
, Se
c. 2
2
Alto
Rio
Le
rma
**
Sa
rigo
l
Pa
no
che
WD
Ad
ala
Bh
aira
wa
Lum
bin
i
Ala
seh
ir
Tu
rgu
tlu
Co
rta
zar M
od
ule
**
Sa
vili
US
do
lla
r p
er
m3
Figure 4: Standardised Gross Value of Production per unit water consumed by ETcrop
* surface water and public wells ** private wells
Large scope to improvePerformance
Water productivity variations
It won’t be easy
Adoption rates are low – water productivity not necessarily a farmer concern, markets may not be in place, need to understand political-economy of water useScale effects - Farm water productivity gains can increase basin depletion, not save water
Need to understand tradeoffs and align incentives of different actors by a variety of means (economic incentives, allocation)
Water Use – Today and 2050
Based on WaterSim analysis for the CA
Today
CA Scenario
No Water Productivity
Gains
CA Scenario: Policies for productivity gains, upgrading rainfed, revitalized irrigation, trade; reducing waste can
further reduce water needs
2050
Summary - Water Agenda
Change national perceptions Water access and productivity – high poverty
reduction potentialTransform water governance
Data, monitoring, modeling and feedback to support adaptive management
Rethink water storage – (eg groundwater banking)Manage water demandGrow more food per unit of water
Revitalize irrigation, upgrade rainfed agriculture