Growing Enough Food

Without Enough Water

David Molden

About IWMI

IWMI is one of 15 research centers supported by the Consultative Group on International Agricultural Research (CGIAR).

Mission: To improve the management of land and water resources for food, livelihoods and the environment.

Where we work:Headquarters: Colombo, Sri LankaIn Africa : Ghana, Southern Africa, EthiopiaIn Asia: India, Pakistan, Nepal, Laos, Vietnam, Central Asia, Syria

Water Scarcity 2000

1/3 of the world’s population live in basins that have to deal with water scarcity

Other Water Pressures

Population & Diet – food grain production projected to increase by 100% by 2050

Urbanization - Cities are projected to use 150% more water in 2025, encroach on ag land

Energy – Hydropower and biofuels compete for water and land

Climate Change – Shifting patterns of water availability

Drivers of Land & Water Use

Land degradation – limits productivityRiver 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

Some areas will be wetter, others drier, more rainfall variability, all hotter

Source: Arnell, 2003 – IWMI, FAO, ADB report on revitalizing irrigation.

Water Scarcity and Climate Change

Some areas wetter, some areas drier

Will there be enough water?

One liter of water produces one calorie on average

Food

Sup

ply

in C

alor

ies

One liter of water produces one calorie on average

USA

projectionsdata

2003

1961 2050

China

India

140

20

120

100

40

60

80

WorldMea

t con

sum

ptio

n kg

/cap

/yr

Per capita meat demand (kg/cap/yr)

More meat and milk requires more feed grain, requiring more 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 2050More calories & more meat, fish, milk

More food production – need to double grain production by 2050

More water for food – if practices don’t change,

water needs for agriculture will double Something has to change

SolutionsOlivia Molden

Water Management

Major Pathways to Meet Future Food & Water Demands

1. Improve water productivity (more food/water)– Irrigation systems– Rainfed systems

2. Expand irrigated & rainfed agriculture3. Promote trade from highly productive to less

productive regions4. Manage demand, consume and waste less

Grow more food per unit of water

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7C

hish

tian

sub-

div.

Mah

i-Kad

ana

Nac

hcha

duw

a

Mud

a

Raj

anga

naya

Nile

Del

ta

Kou

rani

Bar

ia II

Sun

sari

Mor

ang

Gor

go

Wes

t Gan

dak

Mar

chw

ar L

ift

Sag

a

Big

Tho

mps

on

Kha

geri

Pan

chak

anya

Fryi

ngpa

n

Kan

kai

Mog

tedo

Sal

dana

Kou

rani

Bar

ia I

Sey

han

Coe

lla

RU

T

Torre

on

Sal

vatie

rra M

odul

e**

Alto

Rio

Ler

ma

*

Cor

taza

r Mod

ule*

Sal

vatie

rra M

odul

e*

Men

emen

Impe

rial I

D

Man

isa

Sam

aca

Triff

a S

chem

e, S

ec. 2

2

Alto

Rio

Ler

ma

**

Sar

igol

Pan

oche

WD

Ada

la

Bha

iraw

a Lu

mbi

ni

Ala

sehi

r

Turg

utlu

Cor

taza

r Mod

ule*

*

Sav

ili

US

dolla

r per

m3

Figure 4: Standardised Gross Value of Production per unit water consumed by ETcrop

* surface water and public wells ** private wells

Productivity of Water at 40 Irrigation Systems:

There is ample scope for improvement.

Source: Sakthivadivel et al, 1999

Range of water productivities in biological, economical and nutritional terms for selected commodities

aIncludes extensive systems without additional nutritional inputs to superintensive systems

Source: Muir, 1993; Verdegem, Bosma, and Vereth 2006; Renault and Wallender 2000; Oweis and Hachum 2003; Zwart and Bastiannsen 2004

Product

Water ProductivityKilograms per cubic meter ET

Dollars per cubic meter ET

Protein grams per m3

ET

Calories per m3 ET

Wheat ($0.2 per kilogram) 0.2-1.2 0.04-0.30 50-150 660-4,000

Rice ($0.31 per kilogram) 0.15-1.6 0.05-0.18 12-50 500-2,000

Maize (0.11 per kilogram) 0.30-2.00 0.03-0.22 30-200 1,000-

7,000

Beef ($3.0 per kilogram) 0.03-0.1 0.09-0.3 10-30 60-210

Fish (aquaculture)a 0.05-1.0 0.07-1.35 17-340 85-1,750

WP for Livestock and Fish• Beef 0.03 to 0.1 kg/m3 (ET)• Fish 0.05 to 1.0 kg/m3 (ET)Rapid increase in consumption of fish, meat, milk,

with incomeHuge scope for improvement – feed source, and

animal husbandry important

Reasons for Caution

Chishtian

Human

usesSurface

Rain

Groundwater miningEnvironmentalcommitments

Otherevaporation

VegetationCity uses

Crops

740km390%

Accounting for Water Use at Chistian, Pakistan

Often problem is overuse, not low efficiencyLow water productivity is the real waste

Breeding: optimism or caution?• Biophysical limit on biomass/transpiration• Harvest index already maximized – limit on

marketable produce per unit transpiration• Hard to foresee a big jump• except in underutilized, understudied cropsBut helpful in reducing damage from weeds,

insects, minimizing impacts of drought

Water productivity rises faster at lower yields and levels off at higher yields

Source: Adapted from Zwart and Bastiaanssen 2004In Water for Food, Water for Life, Earthscan Publishing

Water productivity is subject to diminishing returns

Source: Based on the yield-water productivity relationship for rainfed cereals in Rockström (2003)

In Water for Food, Water for Life, Earthscan Publishing

Area of Greatest Potential

Areas with high poverty

Opportunities in Rainfed Agriculture• Largest opportunities to build resilience and

improve water productivity are in rainfed landscapes – low productivity, high poverty

• Technology– water harvesting, supplemental irrigation– Field water conservation to reduce

nonproductive evaporation– Improved nutrients – Drought resistance varieties

• Expand “water” to includepolicies and practices forupgrading rainfed systems

Irrigation potential

developed:

Egypt, Morocco,

Somalia, South Africa > 75%

Botswana, Sudan,

Zimbabwe, Madagascar, Mali, Malawi,

Uganda 50-75%

Rest < 50%% Irrigated

LandINDIA:

~50SSA:

5

Rain = 1745 km3

Rainfed ET – 190 km3

Irrigated ET – 67 km3

Outflow – 10 to 30 km3

Limited options to expand irrigation – but gets attention

Ample options to upgrade agriculture on rainfed lands –gets little attention

A green-blue view

Irrigated

Pastoral

Rainfed

Wetlands

Consider A Range of Agricultural Water Management Options

Fish, Livestock, Crops, Ecosystem Services

Transforming Agricultural Water Management

We know what to do – we need to know HOW?

- Use of wells and dug-outs- Small-scale: labour-intensive manual

irrigation - Few commercial farmers : motor pumps- Irrigation during dry season

Crops: Mainly tomato, pepper, local vegetables

Shallow Groundwater Irrigation

• Millions of pumps in operation in S-Asia

• In India >70% of irrigated production

• High demand in SSA • Spontaneous uptake• Privately owned• Enormous impact on

farmer & landless income

But:• Small pumps are inefficient

(50%)• Still quite expensive sales

price and running• Technical knowledge gap• 6% GHG emission in India• Resource sustainability• No women ownership?

Solutions1. Affordable & efficient pump for

smallholders2. Alternative energy sources

(solar)3. Ban import tax on ag equipment

(cost of pump <$100 in India, $140 in Togo, $300 in Ghana). Zambia recently abolished

4. Extension training

Motorized pumps: extreme demand – extreme opportunity for change

Easy to transport: * individual* scattered plots* rent-out

Accra Market Queen

Making it Happen – beyond technologies

• Access to technology, seeds, fertilizers?• Is there enough money

or credit to buy them?• Are markets available to sell?• Financially viable?• Water and land resources available?• Is it sustainable – financial, ecological?• Supportive policies?• “Mind mobilization” Matsepo Khumbane

Summary – Water, Food & Livelihood Agenda

1. Enhance & safeguard water access for the poor

2. Increase water productivity 3. In doing so enhance ecosystem services &

resilience4. Transform water governance and

management

Water access, productivity,and ecosystems for livelihoods

1. Upgrade rainfed areas – manage water & soils2. Revitalize irrigation3. Sustainable groundwater management4. Reuse wastewater safely5. Transform water governance and management6. Support with information systems