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Global water outlook to 2025

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"... Based on a global model of supply and demand for food and water, this report shows that if current water policies continue, farmers will indeed find it difficult to meet the world's food needs. Hardest hit will be the world's poorest people. The results from the model used in this report also show the consequences of changing the course of water policy. Further inattention to water-related investments and policies will produce a severe water crisis, which will lead in turn to a food crisis. A commitment to sustainable use of water, through appropriate policies and investments, however, will lead to a more water- and food-secure world. Water may be a scarce resource, but humans have developed many ways of using it more efficiently — that is, getting more from each unit of water. But water-saving policies, practices, and technologies are of no help if they are not used. Inappropriate incentives and institutions often hinder effective use of water. This report spells out the future results of our current choices." Authors' Introduction
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REPORT
FOOD POLICY
INTERNATIONAL FOOD
POLICY RESEARCH INSTITUTE
sustainable options for ending hunger and poverty
GLOBAL WATER OUTLOOK TO 2025
Averting an Impending Crisis
Mark W. Rosegrant, Ximing Cai, and Sarah A. Cline
THE INTERNATIONAL FOOD POLICY RESEARCH INSTITUTE (IFPRI)
IFPRI was established in 1975 to identify and analyze national and international strategies and policies for
meeting the food needs of the developing world on a sustainable basis, with particular emphasis on low-income
countries and poor people; to make the results of its research available to all those in a position to use them; and
to help strengthen institutions conducting research and applying research results in developing countries.
While IFPRI’s research is geared to the precise objective of contributing to the reduction of hunger and
malnutrition, the factors involved are many and wide-ranging, requiring analysis of underlying processes and
extending beyond a narrowly defined food sector.The Institute’s research programs reflect worldwide
collaboration with governments and private and public institutions interested in increasing food production and
improving the equity of its distribution.
A 2020 VISION FOR FOOD,AGRICULTURE, AND THE ENVIRONMENT is an initiative of IFPRI launched in 1993 in
collaboration with partners around the world.The 2020 Vision Initiative seeks to develop and promote a shared
vision for how to meet the world’s food needs while reducing poverty and protecting the environment and seeks
to generate information and encourage debate to influence action by all relevant parties.
The 2020 Vision Initiative gratefully acknowledges support for its general activities from the following donors:
Canadian International Development Agency (CIDA), Danish International Development Agency (DANIDA),
Swedish International Development Cooperation Agency (SIDA), and Swiss Agency for Development
Cooperation (SDC).
THE INTERNATIONAL WATER MANAGEMENT INSTITUTE (IWMI)
IWMI’s mission is: improving water and land resources management for food, livelihoods, and nature. IWMI
works to: (1) identify the larger issues related to water management and food security that need to be
understood and addressed by governments and policymakers; (2) develop, test, and promote management
practices and tools that can be used by governments and institutions to manage water and land resources more
effectively and address water scarcity issues; (3) clarify the link between poverty and access to water and help
governments and the research community better understand the specific water-related problems of poor
people; and (4) help developing countries build their research capacities to deal with water scarcity and related
food security issues.
IWMI’s agenda is to put research into action through five research themes: Integrated Water Resources
Management for Agriculture, Sustainable Smallholder Land and Water Management, Sustainable Groundwater
Management,Water Resource Institutions and Policies, and Water, Health, and Environment.
The Institute leads three international programs that bring together the expertise of a number of Future
Harvest Centers and other partners, including national research systems and NGOs: the Comprehensive
Assessment of Water Management in Agriculture; the SIMA Malaria and Agriculture initiative; and the CGIAR
Challenge Program on Water and Food.
FUTURE HARVEST
IFPRI and IWMI are two of 16 food and environmental research organizations known as the Future Harvest
Centers.The centers, located around the world, conduct research in partnership with farmers, scientists, and
policymakers to help alleviate poverty and increase food security while protecting the natural resource base.The
Future Harvest Centers are principally funded by governments, private foundations, and regional and
international organizations, most of which are members of the Consultative Group on International Agricultural
Research (CGIAR).
Global Water Outlook to 2025
Averting an Impending Crisis
A 2020 Vision for Food, Agriculture, and the Environment Initiative
International Food Policy Research Institute
Washington, D.C., U.S.A.
International Water Management Institute
Colombo, Sri Lanka
September 2002
Mark W. Rosegrant
Ximing Cai
Sarah A. Cline
The views expressed in this document are those of the authors and are not necessarily endorsed by or representative of the
cosponsoring or supporting organizations.
Copyright © 2002 International Food Policy Research Institute. All rights reserved. Sections of this report may be reproduced
without the express permission of but with acknowledgment to the International Food Policy Research Institute.
ISBN 0-89629-646-6
Co
n
te
n
ts
Preface v
Introduction 1
A Thirsty World 2
Alternative Futures for Water 4
Consequences of Key Policy Changes 17
Implications for the Future 22
Notes 25
Box:The IMPACT-WATER Model 26
Pr
e
f
ace
F
or some time, experts have argued about the Earth’s capacity to support ever larger human popu-
lations. Can the Earth produce enough food to feed 8 billion people? 10 billion? It now appears
that one of the main factors limiting future food production will be water. This scarce resource is
facing heavy and unsustainable demand from users of all kinds, and farmers increasingly have to compete
for water with urban residents and industries. Environmental uses of water, which may be key to
ensuring the sustainability of the Earth’s water supply in the long run, often get short shrift.
Based on a global model of supply and demand for food and water, this report shows that if current
water policies continue, farmers will indeed find it difficult to meet the world’s food needs. Hardest hit
will be the world’s poorest people. The results from the model used in this report also show the conse-
quences of changing the course of water policy. Further inattention to water-related investments and
policies will produce a severe water crisis, which will lead in turn to a food crisis. A commitment to
sustainable use of water, through appropriate policies and investments, however, will lead to a more
water- and food-secure world. Water may be a scarce resource, but humans have developed many ways
of using it more efficiently—that is, getting more from each unit of water. But water-saving policies,
practices, and technologies are of no help if they are not used. Inappropriate incentives and institutions
often hinder effective use of water. This report spells out the future results of our current choices.
Many more details about the scenarios described in this report are available in a book called World
Water and Food to 2025: Dealing with Scarcity, by Mark W. Rosegrant, Ximing Cai, and Sarah A. Cline, also
available from IFPRI.
v
GLOBAL WATER OUTLOOK TO 2025
D
emand for the world’s increasingly scarce water supply is rising rapidly, challenging its
availability for food production and putting global food security at risk. Agriculture,
upon which a burgeoning population depends for food, is competing with industrial,
household, and environmental uses for this scarce water supply. Even as demand for water
by all users grows, groundwater is being depleted, other water ecosystems are becoming
polluted and degraded, and developing new sources of water is getting more costly.
Introduction
Will there be enough water to grow food for
the almost 8 billion people expected to populate
the Earth by 2025? It is impossible to answer
that question without an understanding of the
evolving relationship between water availability
and food production.This understanding will
allow decisionmakers to look squarely at the
consequences of the choices they make to
balance water supply and demand among all users
in the years to come.
To spell out these consequences, we have
developed a global model (see box on page 26) of
water and food supply and demand to address
the following questions: How are water avail-
ability and water demand likely to evolve by the
year 2025? What impact will various water poli-
cies and investments have on water availability for
the environment, domestic and industrial uses,
and irrigation? What steps can policymakers take
to ensure a sustainable use of water that meets
the worlds food needs?
GLOBAL WATER OUTLOOK TO 2025
1
W
ater development underpins food security, peoples livelihoods, industrial growth, and
environmental sustainability throughout the world. In 1995 the world withdrew
3,906 cubic kilometers (km
3
) of water for these purposes (Figure 1). By 2025 water with-
drawal for most uses (domestic, industrial, and livestock) is projected to increase by at least
50 percent. This will severely limit irrigation water withdrawal, which will increase by only 4
percent, constraining food production in turn.
A Thirsty World
About 250 million hectares are
irrigated worldwide today, nearly five
times more than at the beginning of
the 20th century. Irrigation has helped
boost agricultural yields and outputs
and stabilize food production and
prices. But growth in population and
income will only increase the demand
for irrigation water to meet food
production requirements (Figure 2).
Although the achievements of irriga-
tion have been impressive, in many
regions poor irrigation management
has markedly lowered groundwater
tables, damaged soils, and reduced
water quality.
Water is also essential for
drinking and household uses and for
industrial production. Access to safe
drinking water and sanitation is critical
to maintain health, particularly for chil-
dren. But more than 1 billion people
across the globe lack enough safe
water to meet minimum levels of
health and income. Although the
domestic and industrial sectors use far
less water than agriculture, the growth
in water consumption in these sectors
has been rapid. Globally, withdrawals
for domestic and industrial uses
quadrupled between 1950 and 1995,
5,000
4,000
3,000
2,000
1,000
0
Figure 1 Total water withdrawal by region, 1995 and 2025
Asia
World
Latin America
Sub-Saharan
Africa
West Asia/
North Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Developed
countries
1995
2025
Cubic kilometers
Developing
countries
1,600
1,400
1,200
1,000
800
600
400
200
0
Figure 2 Total irrigation water consumption by region, 1995 and 2025
Asia
World
Latin America
Sub-Saharan
Africa
West Asia/
North Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Developed
countries
1995
2025
Cubic kilometers
Developing
countries
GLOBAL WATER OUTLOOK TO 2025
2
compared with agricultural uses, for which with-
drawals slightly more than doubled.
1
Water is integrally linked to the health of the
environment.Water is vital to the survival of
ecosystems and the plants and animals that live in
them, and in turn ecosystems help to regulate the
quantity and quality of water. Wetlands retain
water during high rainfall, release it during dry
periods, and purify it of many contaminants.
Forests reduce erosion and sedimentation of
rivers and recharge groundwater. The importance
of reserving water for environmental purposes has
only recently been recognized: during the 20th
century, more than half of the worlds wetlands
were lost.
2
GLOBAL WATER OUTLOOK TO 2025
3
Business As Usual Scenario
In the business as usual scenario current trends in
water and food policy, management, and investment
remain as they are. International donors and
national governments, complacent about agricul-
ture and irrigation, cut their investments in these
sectors. Governments and water users implement
institutional and management reforms in a limited
and piecemeal fashion.These conditions leave the
world ill prepared to meet major challenges to the
water and food sectors.
Over the coming decades the area of land
devoted to cultivating food crops will grow slowly
in most of the world because of urbanization, soil
degradation, and slow growth in irrigation invest-
ment, and because a high proportion of arable land
is already cultivated. Moreover, steady or declining
real prices for cereals will make it unprofitable for
farmers to expand harvested area. As a result,
greater food production will depend primarily on
increases in yield. Yet growth in crop yields will also
diminish because of falling public investment in agri-
cultural research and rural infrastructure.
Moreover, many of the actions that produced yield
gains in recent decades, such as increasing the
density of crop planting, introducing strains that are
more responsive to fertilizer, and improving
management practices, cannot easily be repeated.
In the water sector, the management of river
basin and irrigation water will become more effi-
cient, but slowly. Governments will continue to
transfer management of irrigation systems to
farmer organizations and water-user associations.
Such transfers will increase water efficiency when
they are built upon existing patterns of coopera-
tion and backed by a supportive policy and legal
environment. But these conditions are often
lacking.
In some regions farmers will adopt more effi-
cient irrigation practices. Economic incentives to
induce more efficient water management,
however, will still face political opposition from
those concerned about the impact of higher
water prices on farmers income and from
entrenched interests that benefit from existing
systems of allocating water.Water management
will also improve slowly in rainfed agriculture as a
result of small advances in water harvesting,
better on-farm management techniques, and the
development of crop varieties with shorter
growing seasons.
Public investment in expanding irrigation
systems and reservoir storage will decline as the
financial, environmental, and social costs of building
new irrigation systems escalate and the prices of
cereals and other irrigated crops drop.
T
he future of water and food is highly uncertain. Some of this uncertainty is due to rela-
tively uncontrollable factors such as weather. But other critical factors can be influ-
enced by the choices made collectively by the worlds people. These factors include income
and population growth, investment in water infrastructure, allocation of water to various
uses, reform in water management, and technological changes in agriculture. Policy deci-
sionsand the actions of billions of individualsdetermine these fundamental, long-term
drivers of water and food supply and demand.
To show the very different outcomes that policy choices produce, we present three alter-
native futures for global water and food, followed by an assessment of specific policy options.
3
Alternative Futures for Water
4
GLOBAL WATER OUTLOOK TO 2025
5
Nevertheless, where benefits outweigh costs, many
governments will construct dams, and reservoir
water for irrigation will increase moderately.
With slow growth in irrigation from surface
water, farmers will expand pumping from ground-
water, which is subject to low prices and little
regulation. Regions that currently pump ground-
water faster than aquifers can recharge, such as the
western United States, northern China, northern
and western India, Egypt, and West Asia and North
Africa, will continue to do so.
The cost of supplying water to domestic and
industrial users will rise dramatically. Better
delivery and more efficient home water use will
lead to some increase in the proportion of house-
holds connected to piped water. Many households,
however, will remain unconnected. Small price
increases for industrial water, improvements in
pollution control regulation and enforcement, and
new industrial technologies will cut industrial water
use intensity (water demand per $1,000 of gross
domestic product). Yet industrial water prices will
remain relatively low and pollution regulations will
often be poorly enforced.Thus, significant potential
gains will be lost.
Environmental and other interest groups will
press to increase the amount of water
allocated to preserving wetlands,
diluting pollutants, maintaining riparian
flora and other aquatic species, and
supporting tourism and recreation.Yet
because of competition for water for
other uses, the share of water devoted
to environmental uses will not
increase.
The Water Situation
Almost all users will place heavy
demands on the worlds water supply
under the business as usual scenario.
Total global water withdrawals in 2025
are projected to increase by 22
percent above 1995 withdrawals, to
4,772 km
3
(see Figure 1, page 2).
4
Projected withdrawals in developing
countries will increase 27 percent
over the 30-year period, while devel-
oped-country withdrawals will
increase by 11 percent.
5
Together, consumption of water for
domestic, industrial, and livestock
usesthat is, all nonirrigation uses
will increase dramatically, rising by 62
percent from 1995 to 2025 (Figure 3).
Because of rapid population growth and
rising per capita water use (Figure 4),
total domestic consumption will
increase by 71 percent, of which more
60
50
40
30
20
10
0
Figure 4 Per capita domestic water consumption by region, 1995 and 2025
Asia
World
Latin America
Sub-Saharan
Africa
W
est Asia/
North Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Devel
oped
countries
1995
2025
Cubic meters/person/year
Developing
countries
600
500
400
300
200
100
0
Figure 3 Total nonirrigation water consumption by region, 1995 and 2025
Asia
World
Latin America
Sub-Saharan
Africa
West Asia/
North Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Developed
countries
1995
2025
Cubic kilometers
Developing
countries
GLOBAL WATER OUTLOOK TO 2025
than 90 percent will be in developing countries.
Conservation and technological improvements will
lower per capita domestic water use in developed
countries with the highest per capita water
consumption.
Industrial water use will grow much faster in
developing countries than in developed countries.
In 1995 industries in developed countries
consumed much more water than industries in the
developing world. By 2025, however, developing-
world industrial water demand is projected to
increase to 121 km
3
,7 km
3
greater than in the
developed world (Figure 5). The intensity of indus-
trial water use will decrease worldwide, especially
in developing countries (where initial intensity
levels are very high), thanks to improvements in
water-saving technology and demand policy.
Nonetheless, the sheer size of the increase in the
worlds industrial production will still lead to an
increase in total industrial water demand.
Direct water consumption by livestock is very
small compared with other sectors. But the rapid
increase of livestock production, particularly in
developing countries, means that livestock water
demand is projected to increase 71 percent
between 1995 and 2025. Whereas livestock water
demand will increase only 19 percent
in the developed world between
1995 and 2025, it is projected to
more than double in the developing
world, from 22 to 45 km
3
.
Although irrigation is by far the
largest user of the worlds water, use
of irrigation water is projected to rise
much more slowly than other
sectors. For irrigation water, we have
computed both potential demand and
actual consumption. Potential demand
is the demand for irrigation water in
the absence of any water supply
constraints, whereas actual consump-
tion of irrigation water is the realized
water demand, given the limitations of
water supply for irrigation (Figure 6).
The proportion of potential demand
that is realized in actual consumption
is the irrigation water supply relia-
bility index (IWSR).
6
An IWSR of 1.0
would mean that all potential demand
is being met.
Potential irrigation demand will
grow by 12 percent in developing
countries, while it will actually decline
in developed countries by 1.5 percent.
The fastest growth in potential
demand for irrigation water will occur
in Sub-Saharan Africa, with an increase
of 27 percent, and in Latin America,
2,500
2,000
1,500
1,000
500
0
Figure 6 Potential and actual consumption of irrigation water, 1995 and 2025
World
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Developed
countries
Cubic kilometers
Developing
countries
1995 Potential irrigation consumption
2025 Potential irrigation consumption
1995 Actual irrigation consumption
2025 Actual irrigation consumption
2,500
2,000
1,500
1,000
500
0
Figure 5 Water consumption by sector, 1995 and 2025
W
orl
d
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Developed
countries
Livestock
Irrigation
Cubic kilometers
Developing
countries
Domestic
Industrial
1995
1995 199520252025
2025
GLOBAL WATER OUTLOOK TO 2025
6
with an increase of 21 percent. Each of these
regions has a high percentage increase in irrigated
area from a relatively low 1995 level. India is
projected to have the highest absolute growth in
potential irrigation water demand, 66 km
3
(17
percent), owing to relatively rapid growth in irri-
gated area from an already high level in 1995. West
Asia and North Africa will increase by 18 percent
(28 km
3
, mainly in Turkey), while China will experi-
ence a much smaller increase of 4 percent (12 km
3
).
In Asia as a region, potential irrigation water demand
will increase by 8 percent (100 km
3
).
Water scarcity for irrigation will intensify, with
actual consumption of irrigation water worldwide
projected to grow more slowly than potential
consumption, increasing only 4 percent between
1995 and 2025. In developing countries a declining
fraction of potential demand will be met over time.
The IWSR for developing countries will decline
from 0.81 in 1995 to 0.75 in 2025, and in dry river
basins the decline will be steeper (Table 1). For
example, in the Haihe River Basin in China, which is
an important wheat and maize producer and serves
major metropolitan areas, the IWSR is projected to
decline from 0.78 to 0.62, and in the Ganges of
India, the IWSR will decline from 0.83 to 0.67.
In the developed world, the situation is the
reverse: the supply of irrigation water is projected
to grow faster than potential demand (although
certain basins will face increasing water scarcity).
Increases in river basin
efficiency will more than
offset the very small
increase in irrigated area.
As a result, after initially
declining from 0.87 to
0.85 in 2010, the IWSR
will improve to 0.90 in
2025 thanks to slowing
growth of domestic and
industrial demand (and
actual declines in total
domestic and industrial
water use in the United
States and Europe) and
more efficient use of irrigation water.
The Food Situation
Water scarcity under business as usual will lead to
slower growth of food production and substantial
shifts in where the worlds food is grown.
Farmers will find themselves unable to raise
crop yields as quickly as in the past in the face of a
decline in relative water supply.The global yield
growth rate for all cereals is projected to decline
from 1.5 percent per year from 1982 to 1995 to
1.0 percent per year from 1995 to 2025. In devel-
oping countries, average crop yield growth will
decline from 1.9 percent per year to 1.2 percent.
The projected relative crop yields for irrigated
cereals show that scarce water is a significant cause
of the slowdown in cereal yield growth in devel-
oping countries. Relative crop yield is the ratio of
the actual projected crop yield to the economically
attainable yields at given crop and input prices under
conditions of zero water stress. The relative crop
yield for cereals in irrigated areas in developing
countries is projected to decline from 0.86 in 1995
to 0.75 in 2025 (Figure 7).This fall in the relative
crop yield represents an annual loss in crop yields
forgone due to increased water stress of 0.68
metric tons per hectare in 2025, or an annual loss of
cereal production of 130 million metric tons, equiva-
lent to the annual rice crop in China in late 1990s
and double the U.S. wheat crop in the same period.
7
Table 1 Irrigation water supply reliability by region, 1995 and 2025
IRRIGATION WATER SUPPLY
RELIABILITY INDEX
REGION 1995 2025
Asia 0.81 0.76
Latin America 0.83 0.75
Sub-Saharan Africa 0.73 0.72
West Asia/North Africa 0.78 0.74
Developed countries 0.87 0.90
Developing countries 0.81 0.75
World 0.82 0.78
SOURCE: Authors estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenario.
GLOBAL WATER OUTLOOK TO 2025
7
Crop-harvested area is expected to grow even
more slowly than crop yield in the coming
decades. Cereal-harvested area will rise by only
64 million hectares by 2025, from 687 million
hectares in 1995. All of this growth is projected to
occur in developing countries, with a slight decline
in cereal-harvested area in developed countries.
Growth in food demand will be concentrated
in developing countries, where rising incomes and
rapid urbanization will also cause people to
change the kinds of food they demand.
Consumers will shift from maize and coarse grains
to wheat and rice, livestock products, and fruits
and vegetables. In much of Asia, an additional shift
will occur from rice to wheat.The projected
strong growth in meat consumption, in turn, will
substantially increase cereal consumption in the
form of animal feed, particularly maize. Total
world cereal demand is projected to grow by 828
million tons, or 47 percent.
With slowing production growth, the prices
of most food commodities are projected to
decline, but far more slowly than in the
past two decades. Maize prices will
increase slightly, while rice, wheat, and
other cereals will all decline in price.
Rice prices show the biggest decline, a
drop of $64 per ton, or 22 percent,
between 1995 and 2025, but this is still
far below the rate of decline in the
past three decades. Real world prices
of wheat, rice, and maize fell by 47, 59,
and 61 percent respectively, between
1970 and 2000.
Under the business as usual
scenario, irrigated and rainfed produc-
tion will each account for about one-
half the increase in production between
1995 and 2025 (Figure 8).The large
contribution to production from
rainfed areas may surprise some
observers. But more than 80 percent
of cereal area in developed countries is
rainfed, and much of this area is highly
productive maize and wheat land. The
average rainfed cereal yield in devel-
oped countries was 3.2 tons per
hectare in 1995, virtually as high as irri-
gated cereal yields in developing coun-
tries, and is projected to grow to 4.0
tons per hectare by 2025. Moreover,
whereas rainfed cereal yields in devel-
oping countries are projected to
increase only from 1.5 tons per hectare
to 2.1 tons per hectare by 2025, rainfed
area in developing countries will
1.2
1.0
0.8
0.6
0.4
0.2
0
Figure 7 Relative cereal yield by region, 1995 and 2025
Asia
World
Latin America
Sub-Saharan
Africa
W
est Asia/
North Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Develo
p
ed
countries
1995
2025
Developing
countries
Figure 8 Share of irrigated and rainfed production in cereal production
increase, 1995 and 2025
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Rainfed
developing
countries
30%
Irrigated
developed countries
11%
Irrigated
developing
countries
39%
Rainfed
developed countries
20%
GLOBAL WATER OUTLOOK TO 2025
8
account for 62 percent of total cereal area in
developing countries (Figure 9).
By substituting cereal and other food imports
for irrigated agricultural production (so-called
imports of virtual water), countries can effectively
reduce their agricultural water use.
8
Under busi-
ness as usual, developing countries will dramatically
increase their reliance on food imports from 107
million tons in 1995 to 245 million tons in 2025.
The increase in developing-country cereal imports
by 138 million tons between 1995 and 2025 is the
equivalent of saving 147 km
3
of water at 2025
water productivity levels, or 8 percent of total
water consumption and 12 percent of irrigation
water consumption in developing countries in 2025.
The water (and land) savings from the projected
large increases of food imports by the developing
countries are particularly beneficial if they are the
result of strong economic growth that generates
the necessary foreign exchange to pay for the food
imports. But even when rapidly growing food
imports are primarily a result of rapid income
growth, national policymakers concerned about
heavy reliance on world markets often see them as
a signal to set trade restrictions that can slow
growth and food security in the longer term. More
serious food security problems arise when high
food imports are the result of slow agricultural and
economic development that fails to keep pace with
basic food demand driven by population and
income growth. Under these condi-
tions, countries may find it impossible
to finance the required imports on a
continuing basis, causing a further
deterioration in the ability to bridge
the gap between food consumption and
the food required for basic livelihood.
Hot spots for food trade gaps
are Sub-Saharan Africa, where cereal
imports are projected to more than
triple by 2025 to 35 million tons, and
West Asia and North Africa, where
cereal imports are projected to
increase from 38 million tons in 1995
to 83 million tons in 2025.The reliance
on water-saving cereal imports in West
Asia and North Africa makes
economic and environmental sense,
but it must be supported by faster
nonagricultural growth. It is highly
unlikely that Sub-Saharan Africa could
finance the projected level of imports
internally; instead international finan-
cial or food aid would be required.
Failure to finance these imports would
further increase food insecurity and
pressure on water resources in this
region.
7
6
5
4
3
2
1
0
Figure 9 Irrigated and rainfed cereal yield by region, 1995 and 2025
Asia
World
Latin America
Sub-Saharan
Africa
West Asia/
North Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: Projections for 2025 are for the business as usual scenerio.
Developed
countries
1995
2025
Metric tons/hectare
Developing
countries
Irrigated yield
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Asia
World
Latin America
S
ub-Saharan
A
frica
West Asia/
North Africa
Developed
countries
1995
2025
Metric tons/hectare
Developing
countries
Rainfed yield
GLOBAL WATER OUTLOOK TO 2025
9
Water Crisis Scenario
A moderate worsening of many of the current
trends in water and food policy and in investment
could build to a genuine water crisis. In the water
crisis scenario, government budget problems
worsen. Governments further cut their spending
on irrigation systems and accelerate the turnover
of irrigation systems to farmers and farmer groups
but without the necessary reforms in water rights.
Attempts to fund operations and maintenance in
the main water system, still operated by public
agencies, cause water prices to irrigators to rise.
Water users fight price increases, and conflict
spills over to local management and cost-sharing
arrangements. Spending on the operation and
maintenance of secondary and tertiary systems
falls dramatically, and deteriorating infrastructure
and poor management lead to falling water use
efficiency. Likewise, attempts to organize river
basin organizations to coordinate water manage-
ment fail because of inadequate funding and high
levels of conflict among water stakeholders within
the basin.
National governments and international
donors will reduce their investments in crop
breeding for rainfed agriculture in developing
countries, especially for staple crops such as rice,
wheat, maize, other coarse grains, potatoes,
cassava, yams, and sweet potatoes. Private agricul-
tural research will fail to fill the investment gap for
these commodities. This loss of research funding
will lead to further declines in productivity growth
in rainfed crop areas, particularly in more marginal
areas. In search of improved incomes, people will
turn to slash-and-burn agriculture, thereby defor-
esting the upper watersheds of many basins.
Erosion and sediment loads in rivers will rise, in
turn causing faster sedimentation of reservoir
storage. People will increasingly encroach on
wetlands for both land and water, and the integrity
and health of aquatic ecosystems will be compro-
mised. The amount of water reserved for environ-
mental purposes will decline as unregulated and
illegal withdrawals increase.
The cost of building new dams will soar,
discouraging new investment in many proposed
dam sites. At other sites indigenous groups and
nongovernmental organizations (NGOs) will
mount opposition, often violent, over the environ-
mental and human impacts of new dams. These
protests and high costs will virtually halt new
investment in medium and large dams and storage
reservoirs. Net reservoir storage will decline in
developing countries and remain constant in
developed countries.
In the attempt to get enough water to grow
their crops, farmers will extract increasing
amounts of groundwater for several years, driving
down water tables. But because of the acceler-
ated pumping, after 2010 key aquifers in northern
China, northern and northwestern India, and West
Asia and North Africa will begin to fail.With
declining water tables, farmers will find the cost of
extracting water too high, and a big drop in
groundwater extraction from these regions will
further reduce water availability for all uses.
As in the business as usual scenario, the rapid
increase in urban populations will quickly raise
demand for domestic water. But governments will
lack the funds to extend piped water and sewage
disposal to newcomers. Governments will respond
by privatizing urban water and sanitation services
in a rushed and poorly planned fashion. The new
private water and sanitation firms will be under-
capitalized and able to do little to connect addi-
tional populations to piped water. An increasing
number and percentage of the urban population
must rely on high-priced water from vendors or
spend many hours fetching often-dirty water from
standpipes and wells.
The Water Situation
The developing world will pay the highest price
for the water crisis scenario. Total worldwide
water consumption in 2025 will be 261 km
3
higher
than under the business as usual scenarioa 13
percent increasebut much of this water will be
wasted, of no benefit to anyone (Figure 10).
GLOBAL WATER OUTLOOK TO 2025
10
GLOBAL WATER OUTLOOK TO 2025
11
Virtually all of the increase will go to
irrigation, mainly because farmers will
use water less efficiently and with-
draw more water to compensate for
water losses.The supply of irrigation
water will be less reliable, except in
regions where so much water is
diverted from environmental uses to
irrigation that it compensates for the
lower water use efficiency.
For most regions, per capita
demand for domestic water will be
significantly lower than under the
business as usual scenario, in both
rural and urban areas.The result is
that people will not have access to
the water they need for drinking and
sanitation. The total domestic demand
under the water crisis scenario will be
162 km
3
in developing countries, 28
percent less than under business as
usual; 64 km
3
in developed countries,
7 percent less than under business as
usual; and 226 km
3
in the world, 23
percent less than under business as
usual (FIgure 11).
Demand for industrial water, on
the other hand, will increase, owing to
failed technological improvements and
economic measures. In 2025 the total
industrial water demand worldwide
will be 80 km
3
higher than under the
business as usual scenarioa 33
percent risewithout generating
additional industrial production.
With water diverted to make up
for less efficient water use, the water
crisis scenario will hit environmental
uses particularly hard. Compared
with business as usual, environmental
flows will drop significantly by 2025,
with 380 km
3
less environmental flow
in the developing world, 80 km
3
less
in the developed world, and 460 km
3
less globally.
350
300
250
200
150
100
50
0
Figure 11 Domestic consumption of water by region, business as usual
and crisis scenarios, 2025
Asia
World
Latin America
Sub-Saharan
Africa
West Asia/
N
ort
h
Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
Developed
countries
Business as usual
Crisis
Cubic kilometers
Developing
countries
2,500
2,000
1,500
1,000
500
0
Figure 10 Total water consumption by region, business as usual and
crisis scenarios, 2025
Asia
World
Latin America
Sub-Saharan
Africa
West Asia/
North Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
Developed
countries
Business as usual
Crisis
Cubic kilometers
Developing
countries
3,000
2,500
2,000
1,500
1,000
500
0
Figure 12 Total cereal production by region, business as usual and crisis
scenarios, 2025
Asia
World
Latin America
Sub
-S
aharan
Africa
West Asia/
North Africa
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
Developed
countries
Business as usual
Crisis
Developing
countries
Million metric tons
The Food Situation
The water crisis scenario will have
severe consequences for food produc-
tion.Total cereal production under
water crisis, for example, will be 249
million metric tons, or 10 percent, less
than business as usualthe result of
declines in both cultivated area and
yields (Figure 12). This reduction is the
equivalent of annually losing the entire
cereal crop of India, or the combined
annual harvest of Sub-Saharan Africa
and West Asia and North Africa.
Compared with business as
usual, the total cereal-harvested area
under the water crisis scenario is
17.7 million hectares, or 3 percent,
lower than business as usual in the
developing world, 8.9 million
hectares, or 4 percent, lower in the
developed world, and 26.6 million
hectares, or 4 percent, lower globally
Yields will fall for both irrigated
and rainfed crops. The average total
cereal yield in 2025 is 216 kilograms
per hectare, or 6 percent, lower
under the water crisis scenario than
under business as usual. Because the
supply of irrigation water in most
regions is less reliable under the
water crisis scenario, the average
yield of irrigated cereals will be lower
for developing and developed coun-
tries and the world as a whole in
2025. Globally, irrigated cereal yields
will be 4 percent lower under water
crisis than under business as usual.
Since farmers fail to harvest more
rainfall and crop research cutbacks
slow yield growth, rainfed crops will
yield 191 kilograms per hectare less
than business as usual, a 7 percent
decrease from 1995 to 2025.
The decline in food production
will help push up food prices sharply
Figure 13 World prices for rice, wheat, and maize, business as usual and
crisis scenarios, 19952025
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
450
400
350
300
250
200
150
100
50
0
Business as usual
Crisis
US$/metric ton
Rice
1995
2000
2005
2010 2015 2020 2025
300
250
200
150
100
50
0
Business as usual
Crisis
US$/metric ton
Wheat
1995
2000
2005
2010 2015 2020 2025
250
200
150
100
50
0
Business as usual
Crisis
US$/metric ton
Maize
1995
2000
2005
2010 2015 2020 2025
GLOBAL WATER OUTLOOK TO 2025
12
under the water crisis scenario (Figure 13,
previous page).The price of rice will rise by 40
percent, wheat by 80 percent, maize by 120
percent, other coarse grains by 85 percent,
soybeans by 70, and potatoes, sweet potatoes, and
other roots and tubers by 50 to 70 percent. Crop
prices under the water crisis scenario in 2025 are
1.8 times that of business as usual for rice, 1.7
times for potatoes, 1.6 times for soybeans, and
more than double for all other crops.
These high prices will dampen food demand.
Under the water crisis scenario, cereal demand
in 2025 will decline by 55 million tons, or 7
percent, compared with the business as usual
scenario in the developed world, and 192 million
tons, or 11 percent, in the developing world.
Compared with business as usual, net trade
will decline in the water crisis scenario.
Developing countries will import 58 million tons,
or 23 percent, less cereal than under business as
usual.This decline implies that high prices dampen
crop demand and thus lead to trade reductions.
The ultimate result of this scenario is growing
food insecurity, especially in developing countries.
Per capita cereal consumption in 2025 in the devel-
oping world is 2 percent lower than 1995 levels.
This scenario makes it clear that increasing
water scarcity, combined with poor water policies
and inadequate investment in water, has the poten-
tial to generate sharp increases in cereal food
prices over the coming decades. Price increases of
this magnitude will take a significant bite out of the
real income of poor consumers. Malnutrition will
increase substantially, given that the poorest
people in low-income developing countries spend
more than half their income on food. Sharp price
increases can also fuel inflation, place severe pres-
sure on foreign exchange reserves, and have
adverse impacts on macroeconomic stability and
investment in developing countries.
Sustainable Water Scenario
A sustainable water scenario would dramatically
increase the amount of water allocated to envi-
ronmental uses, connect all urban households to
piped water, and achieve higher per capita
domestic water consumption, while maintaining
food production at the levels described in the
business as usual scenario. It would achieve
greater social equity and environmental protec-
tion through both careful reform in the water
sector and sound government action.
Governments and international donors will
increase their investments in crop research, tech-
nological change, and reform of water manage-
ment to boost water productivity and the growth
of crop yields in rainfed agriculture. Accumulating
evidence shows that even drought-prone and high-
temperature rainfed environments have the poten-
tial for dramatic increases in yield. Breeding
strategies will directly target these rainfed areas.
Improved policies and increased investment in
rural infrastructure will help link remote farmers
to markets and reduce the risks of rainfed farming.
To stimulate water conservation and free up
agricultural water for environmental, domestic,
and industrial uses, the effective price of water to
the agricultural sector will be gradually increased.
Agricultural water price increases will be imple-
mented through incentive programs that provide
farmers income for the water that they save, such
as charge-subsidy schemes that pay farmers for
reducing water use, and through the establish-
ment, purchase, and trading of water use rights. By
2025 agricultural water prices will be twice as
high in developed countries and three times as
high in developing countries as in the business as
usual scenario.The government will simultane-
ously transfer water rights and the responsibility
for operation and management of irrigation
systems to communities and water user associa-
tions in many countries and regions. The transfer
of rights and systems will be facilitated with an
improved legal and institutional environment for
preventing and eliminating conflict and with tech-
nical and organizational training and support.As a
result, farmers will increase their on-farm invest-
ments in irrigation and water management tech-
nology, and the efficiency of irrigation systems and
basin water use will improve significantly.
GLOBAL WATER OUTLOOK TO 2025
13
River basin organizations will be established in
many water-scarce basins to allocate mainstream
water among stakeholder interests. Higher
funding and reduced conflict over water, thanks to
better water management, will facilitate effective
stakeholder participation in these organizations.
Farmers will be able to make more effective
use of rainfall in crop production, thanks to
breakthroughs in water harvesting systems and
the adoption of advanced farming techniques, like
precision agriculture, contour plowing, precision
land leveling, and minimum-till and no-till tech-
nologies. These technologies will increase the
share of rainfall that goes to infiltration and evap-
otranspiration.
Spurred by the rapidly escalating costs of
building new dams and the increasingly apparent
environmental and human resettlement costs,
developing and developed countries will reassess
their reservoir construction plans, with compre-
hensive analysis of the costs and benefits,
including environmental and social effects, of
proposed projects. As a result, many planned
storage projects will be canceled, but others will
proceed with support from civil society groups.
Yet new storage capacity will be less necessary
because rapid growth in rainfed crop yields will
help reduce rates of reservoir sedimentation
from erosion due to slash-and-burn cultivation.
Policy toward groundwater extraction will
change significantly. Market-based approaches
will assign rights to groundwater based on both
annual withdrawals and the renewable stock of
groundwater. This step will be combined with
stricter regulations and better enforcement of
these regulations. Groundwater overdrafts will be
phased out in countries and regions that previ-
ously pumped groundwater unsustainably.
Domestic and industrial water use will also
be subject to reforms in pricing and regulation.
Water prices for connected households will
double, with targeted subsidies for low-income
households. Revenues from price increases will
be invested to reduce water losses in existing
systems and to extend piped water to previously
unconnected households. By 2025 all households
will be connected. Industries will respond to
higher prices, particularly in developing countries,
by increasing in-plant recycling of water, which
reduces consumption of water.
With strong societal pressure for improved
environmental quality, allocations for environ-
mental uses of water will increase. Moreover, the
reforms in agricultural and nonagricultural water
sectors will reduce pressure on wetlands and
other environmental uses of water. Greater
investments and better water management will
improve the efficiency of water use, leaving more
water instream for environmental
purposes. All reductions in domestic
and urban water use, due to higher
water prices, will be allocated to
instream environmental uses.
The Water Situation
In the sustainable water scenario the
world consumes less water but
reaps greater benefits than under
business as usual, especially in devel-
oping countries. In 2025 total world-
wide water consumption is 408 km
3
,
or 20 percent, lower under the
sustainable scenario than under busi-
ness as usual (Figure 14). This reduc-
2,500
2,000
1,500
1,000
500
0
Figure 14 Total and irrigation water consumption, by region,
business as usual and sustainable scenarios, 2025
World
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
Cubic kilometers
Developing countries
Irrigation
Other uses
Business
as usual
Developed countries
Business
as usual
Business
as usual
Sustainable
Sustainable
Sustainable
GLOBAL WATER OUTLOOK TO 2025
14
tion in consumption frees up water for environ-
mental uses. Higher water prices and higher
water use efficiency reduces consumption of irri-
gation water by 296 km
3
compared with business
as usual. The reliability of irrigation water supply
is reduced slightly in the sustainable scenario
compared with business as usual, because this
scenario places a high priority on environmental
flows. Over time, however, more efficient water
use in this scenario counterbalances the transfer
of water to the environment and results in an
improvement in the reliability of supply of irriga-
tion water by 2025.
This scenario will improve the domestic
water supply through universal access to piped
water for rural and urban households. Globally,
potential domestic water demand under the
sustainable water scenario will decrease 9
percent compared with business as usual, owing
to higher water prices. However, potential per
capita domestic demand for connected house-
holds in rural areas will be 12 percent higher
than that under business as usual in the devel-
oping world, and 5 percent higher in the devel-
oped world. This increase is accomplished by
expanding universal access to piped water in
rural areas even with higher prices
for water. And in urban areas,
potential per capita water consump-
tion for poor households sharply
improves through connection to
piped water, while the initially
connected households reduce
consumption in response to higher
prices and improved water-saving
technology (Figure 15).
Through technological improve-
ments and effective economic incen-
tives, the sustainable water scenario
will reduce industrial water demand.
In 2025 total industrial water
demand worldwide under the
sustainable scenario will be 85 km
3
,
or 35 percent, lower than under
business as usual.
The environment is a major beneficiary of the
sustainable water scenario, with large increases in
the amount of water reserved for wetlands,
instream flows, and other environmental
purposes. Compared with the business as usual
scenario, the sustainable scenario will also result
in an increase in the environmental flow of 850
km
3
in the developing world, 180 km
3
in the
developed world, and 1,030 km
3
globally. This is
the equivalent of transferring 22 percent of global
water withdrawals under business as usual to
environmental purposes.
The Food Situation
The sustainable water scenario can raise food
production slightly over the business as usual
scenario, while achieving much greater gains for
domestic water use and the environment.
The total harvested area under the sustain-
able water scenario in 2025 will be slightly lower
than under business as usual owing to less water
for irrigation and barely lower crop prices.
Because the supply of irrigation water will be less
reliable under the sustainable water scenario
than under business as usual, the yield of irrigated
120
100
80
60
40
20
0
Figure 15 Potential per capita domestic water consumption by connected
rural and urban households, business as usual and sustainable
scenarios, 2025
World
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
Cubic meters/person/year
Developing countries
Rural
Urban
Business
as usual
Developed countries
Business
as usual
Business
as usual
Sustainable
Sustainable
Sustainable
GLOBAL WATER OUTLOOK TO 2025
15
cereals will be 2 percent lower for the world as a
whole in 2025. On the other hand, global rainfed
yields under the sustainable water scenario will
be 7 percent higher than business as usual, owing
to higher agricultural research investment and a
larger improvement in rainfall harvesting.With
the faster growth in rainfed yields making up for
slower growth in harvested area and irrigated
yields, total cereal production in 2025 will be 19
million tons, or 1 percent, more under the
sustainable scenario than under business as usual.
Crop prices under this scenario will decline
slowly from 1995 to 2025 except for slight
increases for maize and soybeans due to heavy
demand for livestock feeds (Figure 16).
As in the water crisis scenario, net trade in
the sustainable scenario is lower than that under
business as usual, with cereal imports from the
developing world declining by 14 million tons,
or 6 percent. This decline reflects the different
rates of adjustment of food production between
food-importing and -exporting countries. Cereal
production under the sustainable water scenario
is 10 million tons less in developed countries and
29 million tons more in developing countries than
under the business as usual scenario.
The sustainable scenario shows that with
improved water policies, investments, and rainfed
cereal crop management and technology, growth
in food production can be maintained while
universal access to piped water is achieved and
environmental flows are increased dramatically.
Compared with the water crisis scenario, the
increase in environmental flows under the
sustainable water scenario is about 1,490 km
3
,
equivalent to 5 times the annual flow of the
Mississippi River, 20 times the annual flow of the
Yellow River, and 4 times the annual flow of the
Ganges River.
300
250
200
150
100
50
0
Figure 16 World food prices, business as usual and sustainable scenarios, 2025
Rice
Sweet
potatoes
Wheat
Maize
Other coarse
grains
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
Soybeans
Business as usual
Sustainable
US$/metric ton
P
otatoes
Other roots
and tubers
GLOBAL WATER OUTLOOK TO 2025
16
Raising Water Prices
Raising water prices seems to make sense for
several reasons. Higher water prices not only
encourage all users to use water more efficiently,
but also could generate funds to maintain existing
water infrastructure and to build new infrastruc-
ture.Yet because of perceived political risks and
concern that higher prices would hurt poor
farmers and consumers, there have been few
attempts to implement higher water prices. In
fact, in most instances the poor suffer from
current subsidized water prices because water
subsidies in most countries go disproportionately
to the better off: urban water users connected to
the public system and irrigated farmers.
Well-designed price hikes for water can
create incentives for people to use water effi-
ciently and recover at least operation and main-
tenance costs, while protecting and even
increasing farm incomes. But would such water
price increases save significant amounts of water
that could be left instream for environmental
purposes without reducing food production?
To address this question, we examine two
scenarios with higher water pricing. One imple-
ments higher water prices but with water use
efficiency remaining the same as under the busi-
ness as usual scenario. The other scenario
assumes higher water prices but also assumes
that higher water prices induce improvements in
basin efficiency through better crop water
management and investments in new irrigation
technology compared with the business as usual
scenario. Under both scenarios, water prices for
agriculture, industry, and connected households
are assumed to increase gradually over the
period from 2000 to 2025. By 2025 water prices
for industrial water use are 1.75 times higher
than prices under the business as usual scenario
in developed countries and 2.25 times higher in
developing countries. For domestic water uses,
water prices are 1.5 times higher in developed
countries and double in developing countries.
For agricultural water uses, prices double by
2025 in developed countries and triple in devel-
oping countries compared with the business as
usual prices.
The higher-price scenarios result in a reduc-
tion of water withdrawals of 839 km
3
(18
percent) and of total water consumption of 287
km
3
(14 percent) compared with business as
usual, with more than half of the reduction occur-
ring in developing countries. Withdrawals and
consumption are the same in the two scenarios;
higher efficiency influences the proportion of
withdrawals and consumption that are used
beneficially.The impact on water withdrawal is
even greater in some regions, with reductions of
more than 20 percent in China, Southeast Asia,
Latin America, and West Asia and North Africa,
and between 14 and 20 percent in other coun-
tries and regions. The reduction in withdrawals
and consumption thus represents a major benefit
for the environment, dramatically increasing envi-
ronmental flows.
Demand for water for all nonirrigation uses
that is, for industrial, domestic, and livestock use
falls dramatically under the higher-price scenarios
compared with business as usual. Total nonirriga-
tion consumption of water falls from 599 km
3
under the business as usual scenario to 449 km
3
globally, from 395 km
3
to 285 km
3
in developing
Consequences of Key Policy Changes
I
f policymakers do not make a holistic change in water policies and investments but
simply change certain key factors, could this produce substantial benefits? We examine
what would happen if policymakers and water users raised water prices, shifted to sustain-
able groundwater use, or better exploited the potential of rainfed agriculture.
GLOBAL WATER OUTLOOK TO 2025
17
countries, and from 204 km
3
to 164 km
3
in devel-
oped countries.Water withdrawals for these
purposes also fall significantly.
Total consumption of irrigation water under
both the higher-price and the higher-price/higher-
efficiency scenarios is about 100 km
3
less than
under the business as usual scenario. Yet because
of more efficient water use in the higher-
price/higher-efficiency scenario, more of the irri-
gation water is consumed beneficially by crops.
Whereas cereal production declines by about 5
percent in the higher-price scenario compared
with business as usual, under the higher-price/
higher-efficiency scenario the change in cereal
production is slight.
With the decline in production under the
higher-price scenario, world food prices increase,
with the greatest increase for rice (10 percent)
and price increases of 48 percent for other
cereals. When water prices induce higher basin
efficiency, however, food prices are the same or
lower (Figure 17).
These results show that higher water prices
for industry, domestic, and agricultural sectors
would result in large water savings that can be
used for environmental purposes. Making water
use more efficient in conjunction with higher
prices is critical to maintaining or increasing the
reliability of irrigation water supply and food
production compared with business as usual.
Shifting to Sustainable
Groundwater Use
A number of basins and countries are pumping
groundwater in excess of natural recharge rates.
These include the Rio Grande and Colorado
River Basins in the western United States, the
Yellow and Haihe River Basins in northern China,
and several river basins in northern and western
India, Egypt, and West Asia and North Africa.
What would happen to water and food if these
regions stopped overpumping and returned to
sustainable water use?
The low-groundwater-pumping scenario
assumes that all countries and regions will phase
out unsustainable groundwater overdraft over
the next 25 years.Areas with more plentiful
groundwater will increase their pumping almost
as much as in the business as usual scenario.
Total global groundwater pumping will fall to 753
km
3
in 202125, a decline from the 1995 value of
817 km
3
and from the 2025 business as usual
value of 922 km
3
. Compared with business as
usual, global consumptive water use will decline
5.6 percent in the irrigation sector,
0.5 percent in the livestock sector,
0.1 percent in the domestic sector,
and 0.1 percent in the industrial
sector, with most of this change
occurring in developing countries.
Virtually no change in consumption
will occur in other sectors.
In 202125 the total area planted
to cereals will be 730,000 hectares
less under the low-groundwater
scenario than under business as
usual. Although rainfed area will
increase, it will not be enough to
offset the large decline in irrigated
area. Most of the change in irrigated
area will occur in developing coun-
tries, especially in China. In most
Figure 17 World cereal prices under business as usual and alternative water
price scenarios, 2021-25
300
250
200
150
100
50
0
Rice
Wheat
Other coarse
grains
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
Business as usual
Higher price
Higher price/higher efficiency
US$/metric ton
Maize
GLOBAL WATER OUTLOOK TO 2025
18
regions yields for irrigated cereals will fall and
yields for rainfed cereals will rise slightly.
Total cereal production will decline by an
annual average of 18 million tons from business
as usual projections in 202125. The fall in irri-
gated cereal production will lead to price
increases that stimulate increased rainfed produc-
tion, but, once again, the increase will not be
enough to overcome the decline in irrigated
cereal production. Crop prices under the low-
groundwater scenario are projected to be 510
percent higher in 202125 than under business as
usual projections. Although total developing-
country cereal production will decline in the low-
groundwater scenario compared with business as
usual in 202125, these price rises will actually
cause farmers in developed countries to produce
more cereals and thus lead to an overall increase
in cereal production there compared with busi-
ness as usual.
Not surprisingly, the low-groundwater
scenario projects the biggest drops in cereal
production to be concentrated in the basins that
currently experience large overdrafts, especially
China and India. As a result, the developing world
as a whole will increase its net imports, with
major increases concentrated in China and India,
and developed countries will increase their net
exports.
These country-level shortfalls in demand and
increases in imports could be serious, but they
may be a worthwhile trade-off for restoring
sustainable groundwater supplies. More impor-
tant, countries must combine a phase-out of
groundwater overdrafting with policies to miti-
gate the impacts on the overdrafting regions in
order to maintain income growth. Countries
should increase their agricultural research invest-
ments, and, particularly in the hardest-hit river
basins, make investments and implement policy
reforms to increase basin efficiency, and
encourage diversification from irrigated cereals
to crops that give more value per unit of water.
Exploiting the Potential of
Rainfed Agriculture
Could more rapid growth in rainfed cereal
productionthrough either research and
technology-driven growth in cereal yield and area
or through increased rainfall harvesting
compensate for significant reductions in irrigation
and water supply investment compared with
business as usual? We explore these questions in
two alternative scenarios.
The low-investment scenario assumes that
basin efficiency will not increase above 1995
levels, that the rate of increase in potential irri-
gated area will be about one-third of the rate
under the business as usual scenario, that the
increase in reservoir storage will be 40 percent
of business as usual, and that increases in
maximum allowable water withdrawals will be 30
percent as high. This reduction in investment in
infrastructure and management seriously
constrains growth in food production, causing an
annual drop in irrigated cereal production of 120
million tons (11 percent) in 202125 and driving
cereal prices up by 2535 percent.
We then estimate the required rainfed area
and yield increases to offset the reduction of irri-
gated production and maintain essentially the
same international trade prices. A larger increase
is assigned to rainfed yield than area (because of
limited potential for area expansion), and a larger
increase is assigned to those basins, countries, or
regions where irrigation effects are greater.
Under this scenario the international price
will maintain approximately the same level as the
business as usual scenario for all cereal crops
except rice. It proved impossible to fully
compensate for the loss of rice production, which
has a high proportion of irrigated area.
Compared with business as usual, this scenario
results in a decline in global irrigation water
consumption of 240 km
3
, or 16 percent, and a
decline in irrigated cereal production of 153
million tons. Rainfed area, however, increases by
GLOBAL WATER OUTLOOK TO 2025
19
10 million hectares, mostly in developing countries.
Rainfed yields increase by 11 percent, and rainfed
production increases by 187 million tons
compared with business as usual. The share of the
worlds cereal produced on rainfed lands will
increase significantly, to 62 percent globally, 51
percent in developing countries, and 78 percent in
developed countries, compared with 56, 43, and 74
percent, respectively, under business as usual.
The second scenario looks at the possibility
of increasing effective rainfall use through water
harvesting, conservation tillage, and precision
farming to counteract the reduction of irrigated
production due to low investment in irrigation
development and water supply. Effective rainfall
use increases by 1015 percent above 1995 levels
from 1995 to 2025 in those basins and countries
with rainwater shortages for crop production,
including river basins in the western United
States, northern and western China, northern and
western India, and countries in West Asia and
North Africa. An increase ranging from 5 to 10
percent is projected for other regions. These
rates compare to 35 percent increases under
business as usual.
Under this scenario world cereal prices
(especially for rice) are higher than those under
business as usual. The projected increase in effec-
tive rainfall water use cannot fully compensate
for the irrigation decline. Although the global
production of rainfed cereals is 126 million tons
more than under business as usual, irrigated
production is 131 million tons lower (Figure 18).
Developing countries are harder hit, with a short-
fall in total cereal production of 42 million tons
(2.8 percent) that causes a reduction in demand
of 26 million tons and an increase in imports of
16 million tons. Nevertheless, the results show
significant benefits from better management that
generates higher effective rainfall.
These scenarios show that there is significant
potential for increasing rainfed production to
compensate for lower investment in irrigation.
Appropriate investments and policy reforms,
however, will be required to enhance the contri-
bution of rainfed agriculture. In some regions
water harvesting has the potential to improve
rainfed crop yields. But crop breeding for rainfed
environments is crucial to future cereal yield
growth. Strong progress has been made in
breeding for enhanced crop yields in rainfed
areas, even in the less favorable environments.
The continued application of conventional
breeding and the recent developments in
nonconventional breeding offer
considerable potential for improving
cereal yield growth in rainfed envi-
ronments. Progress could be
hastened by extending research to
farmers and by using tools derived
from biotechnology to assist conven-
tional breeding (Table 2).
Governments must also combine
crop research targeted to rainfed
areas with increased investment in
rural infrastructure and policies to
close the gap between potential and
actual yields in rainfed areas.
Important policies include higher
priority for rainfed areas in agricul-
tural extension services and access
to markets, credit, and input supplies.
3,000
2,500
2,000
1,500
1,000
500
0
Figure 18 Rainfed and irrigated cereal production, business as usual and
lower irrigation investment and higher effective rainfall use
scenarios, 202125
World
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: LINV-HIER stands for lower irrigation investment and higher effective
rainfall use.
Million metric tons
Developing countries
Rainfed production
Irrigated production
Business
as usual
Developed countries
Business
as usual
Business
as usual
LINV-HIER
LINV-HIER LINV-HIER
GLOBAL WATER OUTLOOK TO 2025
20
Table 2 Rainfed and irrigated cereal yield by region, for three scenarios: business as usual, lower
irrigation investment and higher rainfed area and yield, and lower irrigation investment
and higher effective rainfall use, 202125
SOURCE: Authors' estimates and IMPACT-WATER projections, June 2002.
NOTE: BAU stands for business as usual, LINV-HRF stands for lower irrigation investment and higher rainfall area and yield, and
LINV-HIER stands for lower irrigation investment and higher effective rainfall use.
Rainfed yield (metric tons/hectare) Irrigated yield (metric tons/hectare)
REGION BAU LINV-HRF LINV-HIER BAU LINV-HRF LINV-HIER
Asia 2.46 2.96 2.49 4.50 4.05 4.13
Latin America 2.92 3.13 3.08 5.46 4.85 4.92
Sub-Saharan Africa 1.19 1.22 1.30 3.08 2.95 2.99
West Asia/North Africa 1.75 1.93 1.89 4.86 4.55 4.61
Developed countries 3.89 4.24 3.95 5.97 5.54 5.59
Developing countries 2.08 2.36 2.18 4.53 4.09 4.16
World 2.77 3.07 2.86 4.80 4.37 4.43
GLOBAL WATER OUTLOOK TO 2025
21
W
ater scarcity will get much worse if policy and investment commitments from
national governments and international donors and development banks weaken
further. The water crisis scenariopredicated on the worsening of a number of already
evident trendswould lead to a breakdown in domestic water service for hundreds of
millions of people, devastating loss of wetlands, serious reductions in food production, and
skyrocketing food prices that would force declining per capita food consumption in much
of the world. Failure to adopt water-saving technology improvements and policy reforms
could make demand for nonirrigation water grow even faster than we projected, further
worsening water scarcity.
Implications for the Future
Water scarcity can lead to declining food
demand and increasing food prices. As shown in
the water crisis scenario, major cereal crop prices
may be more than double the projections under
the business as usual scenario, and at the same time
food demand may be significantly reduced, espe-
cially in developing countries. Moreover, price
increases can have an even larger impact on low-
income consumers.
Excessive diversion of water flows and over-
draft of groundwater have already caused environ-
mental problems in many regions around the
world. Our analysis shows that the problems, from
a local to a worldwide scale, will likely be even
more serious in the future. If current investment
plans and recent trends in the water and food
sectors continue, expanding the environmental uses
of water would require reducing the consumption
of irrigation water or domestic and municipal
water or both. Thus, in the absence of policy and
investment reform, competition over water
between households and industries and between
farmers and environmental uses will increase in
many parts of the world.
With water becoming increasingly scarce,
continued high flow diversions would become self-
defeating. Excess extraction speeds the recession
of ecological systems and lowers water quality,
finally reducing the qualified water supply for
human uses.This has already occurred in the Aral
Sea Basin in Central Asia. Groundwater overdraft
can likewise lead to the loss of an important water
source for human uses, as is already happening in
many regions.
However, the analysis also reveals cause for
hope. The scenarios explored in this report point
to three broad strategies that can address the chal-
lenge posed by water scarcity for food production:
1. invest in infrastructure to increase the supply of
water for irrigation, domestic, and industrial
purposes;
2. conserve water and improve the efficiency of
water use in existing systems through reforms in
water management and policy; and
3. improve crop productivity per unit of water and
land through integrated water management and
agricultural research and policy efforts, including
crop breeding and water management for rainfed
agriculture.
Although the financial, environmental, and social
costs of new water supply projects are high, in
some regions, especially in developing countries, it
is still crucial to selectively expand water supply,
storage, and withdrawal capacities. Storage and
water distribution systems (such as water lift proj-
ects and canals) are particularly needed for Sub-
GLOBAL WATER OUTLOOK TO 2025
22
Saharan Africa, some countries in South and
Southeast Asia (such as Bangladesh, India, and Viet
Nam), and some countries in Latin America. These
countries must consider not only the full social,
economic, and environmental costs of develop-
ment, but also the costs of failure to develop new
water sources. Projects must be designed to
account for full costs and benefits, including not
only irrigation benefits, but also health, household
water use, and catchment improvement benefits. It
is also essential to improve compensation
programs for those who are displaced or negatively
affected by water projects.
Expanding water supplies can help alleviate
water scarcity, but the results show that the most
promising avenue is likely to be water management
reforms, incentive policies, and investments in infra-
structure and technology to enhance efficiency in
existing uses. Throughout this report, we have
shown that feasible improvements in the efficiency
of basin-scale irrigation water use can, on a global
scale, compensate for irrigation reduction resulting
from (1) the phasing out of groundwater overdraft
worldwide; (2) increased committed environmental
flows; (3) higher prices for agricultural water use
(which themselves encourage investments in
improved efficiency); and (4) low irrigated area
development. We have also shown that improving
irrigation water use efficiency is an effective way to
increase water productivity.
In severely water-scarce basins, however, rela-
tively little room exists for improving water use
efficiency, and food production and farm incomes
could fall significantly if water for irrigation is trans-
ferred to other uses. In these basins, governments
will need to compensate for the negative impact of
growing water scarcity on agriculture by alternative
means, such as investing in agriculture to obtain
more rapid growth in crop yields, promoting the
diversification of farming into less water-intensive
crops, and diversifying the economy to reduce the
economic role of agriculture over time.
Making big improvements in river basin effi-
ciency in specific river basins will require site-
specific analysis and implementation. Basin
efficiency depends on improvements both in water-
saving technologies and in the institutions
governing water allocation, water rights, and water
quality. Industrial water recycling, such as recircula-
tion of cooling water, can be a major source of
water savings in many countries. Much potential
also exists for improving the efficiency of domestic
water use. Steps may include anything from
detecting and repairing leaks in municipal systems
to installing low-flow showerheads and low-water
or waterless toilets. Treated wastewater can be
used for a variety of nonpotable purposes including
landscape and recreational irrigation, maintenance
of urban stream flows and wetlands, wastewater-
fed aquaculture, and toilet flushing. To encourage
water-saving innovation, domestic and industrial
water prices should be increased. Generalized
subsidies should be replaced with subsidies
targeted to the poor.Water providers should
charge low prices for a basic entitlement of water,
with increasing prices for greater amounts of
water.
Improvements in the irrigation sector can be
made at the technical, managerial, and institutional
levels. Technical improvements include advanced
irrigation systems such as drip irrigation, sprinklers,
conjunctive use of surface and groundwater, and
precision agriculture, including computer moni-
toring of crop water demand. Managerial improve-
ments include the adoption of demand-based
irrigation scheduling systems and improved equip-
ment maintenance. Institutional improvements
involve the establishment of effective water user
associations and water rights, the creation of a
better legal environment for water allocation, and
the introduction of higher water prices. Great care
must be taken in designing a water pricing system
for agriculture. Direct water price increases are
likely to be punitive to farmers because water plays
such a large role in their cost of production. Better
alternatives would be pricing schemes that pay
farmers for reducing water use, and water rights
and water trading arrangements that provide
farmers or water user associations with incentives
to reduce wasteful water use.
GLOBAL WATER OUTLOOK TO 2025
23
Rainfed agriculture emerges from the analysis
as a potential key to sustainable development of
water and food. Rainfed agriculture still produces
about 60 percent of total cereals, and its role
remains very important in both the business as
usual and the sustainable water scenarios.
Improved water management and crop produc-
tivity in rainfed areas would relieve considerable
pressure on irrigated agriculture and on water
resources. Exploiting the full potential of rainfed
agriculture, however, will require investing in water
harvesting technologies, crop breeding targeted to
rainfed environments, agricultural extension serv-
ices, and access to markets, credit, and input
supplies in rainfed areas.
A large part of the world is facing severe
water scarcity, but the impending water crisis can
be averted. The precise mix of water policy and
management reforms and investments, and the
feasible institutional arrangements and policy
instruments to be used, must be tailored to
specific countries and basins.They will vary based
on level of development, agroclimatic conditions,
relative water scarcity, level of agricultural intensifi-
cation, and degree of competition for water. But
these solutions are not easy, and they take time,
political commitment, and money. Fundamental
reform of the water sector must start now.
GLOBAL WATER OUTLOOK TO 2025
24
GLOBAL WATER OUTLOOK TO 2025
25
Notes
1. W. J. Cosgrove and F. Rijsberman, World Water Vision: Making Water Everybody’s Business (London:World
Water Council and World Water Vision and Earthscan, 2000); I. A. Shiklomanov,Electronic Data
Provided to the Scenario Development Panel,World Commission on Water for the 21st Century
(State Hydrological Institute, St. Petersburg, Russia, 1999), mimeo.
2. E. Bos and G. Bergkamp,Water and the Environment, in Overcoming Water Scarcity and Quality
Contraints, 2020 Focus 9, ed. R. S. Meinzen-Dick and M.W. Rosegrant (Washington, D.C.: International
Food Policy Research Institute, 2001).
3. The business as usual, crisis, and sustainable scenarios are compared using average 2025 results gener-
ated from 30 hydrologic scenarios. The other scenarios are compared with business as usual based on
a single 30-year hydrologic sequence drawn from 196190, and results are shown as the average of the
years 202125.
4. Water demand can be defined and measured in terms of withdrawals and actual consumption. While
water withdrawal is the most commonly estimated figure, consumption best captures actual water use,
and most of our analysis will utilize this concept.
5. The global projection is broadly consistent with other recent projections to 2025, including the 4,580
km
3
in the medium scenario of J.Alcamo, P. Döll, F. Kaspar, and S. Sieberg, Global Change and Global
Scenarios of Water Use and Availability:An Application of Water GAP 1.0 (Kassel, Germany: Center for
Environmental System Research, University of Kassel, 1998), the 4,569 km
3
in the business-as-usual
scenario of D. Seckler, U.Amarasinghe, D. Molden, S. Rhadika, and R. Barker, World Water Demand and
Supply, 1990 to 2025: Scenarios and Issues, Research Report Number 19 (Colombo, Sri Lanka:
International Water Management Institute, 1998), and the forecast of 4,966 km
3
(not including reser-
voir evaporation) of Shiklomanov,Electronic Data.
6. Compared with other sectors, the growth of irrigation water potential demand is much lower, with 12
percent growth in potential demand between 1995 and 2025 in developing countries and a slight
decline in potential demand in developed countries.
7. All tons mentioned in this report are metric tons.
8. J. A.Allan,Water Security Policies and Global Systems for Water Scarce Regions, in Sustainability of
Irrigated AgricultureTransactions,Vol. 1E, special session:The Future of Irrigation under Increased
Demand From Competitive Uses of Water and Greater Needs for Food SupplyR.7 in the sympo-
sium on Management Information Systems in Irrigation and Drainage, 16th Congress on Irrigation and
Drainage, Cairo (New Delhi: International Commission on Irrigation and Drainage, 1996).
To explore the relationships among water, environment, and food production, we developed
a global modeling framework, IMPACT-WATER, that combines an extension of the
International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT)
with a newly developed Water Simulation Model (WSM).
1
IMPACT is a partial equilibrium
model of the agricultural sector, representing a competitive agricultural market for crops
and livestock. Demand is a function of prices, income, and population growth. Growth in
crop production in each country is determined by crop and input prices and the rate of
productivity growth. World agricultural commodity prices are determined annually at levels
that clear international markets. IMPACT generates projections for crop area; yield;
production; demand for food, feed, and other uses; prices; and trade. For livestock, IMPACT
projects numbers, yield, production, demand, prices, and trade.
For this study we integrated the IMPACT model with WSM, a basin-scale model of water
resource use, to create a linked model, IMPACT-WATER. We made the linkage by (1)
incorporating water in the crop area and yield functions; and (2) simultaneously determining
water availability at the river basin scale, water demand by irrigation and other sectors, and
crop production. IMPACT-WATER divides the world into 69 spatial units, including macro
river basins in China, India, and the United States and aggregated basins over other
countries and regions. Domestic and industrial water demands are estimated as a function
of population, income, and water prices. Water demand in agriculture is projected based on
irrigation and livestock production growth, water prices, climate, and water use efficiency for
irrigation at the basin level. Then water demand is incorporated as a variable in the crop
yield and area functions for each of eight major food crops: wheat, rice, maize, other coarse
grains, soybeans, potatoes, yams and sweet potatoes, and cassava and other roots and
tubers. Water requirements for all other crops are estimated as a single aggregate demand.
We treat water availability as a stochastic variable with observable probability
distributions. WSM simulates water availability for crops at a river basin scale, taking into
account precipitation and runoff, water use efficiency, flow regulation through reservoir and
groundwater storage, nonagricultural water demand, water supply infrastructure and
withdrawal capacity, and environmental requirements at the river basin, country, and
regional levels. Environmental impacts can be explored through scenario analysis of
committed instream and environmental flows, salt leaching requirements for soil salinity
control, and alternative rates of groundwater pumping.
1
For a more detailed description of the integrated model, see M.W. Rosegrant, X. Cai, and S.A. Cline, World Water and
Food to 2025: Dealing with Scarcity (Washington, D.C.: International Food Policy Research Institute, 2002).
The IMPACT-WATER Model
GLOBAL WATER OUTLOOK TO 2025
26
2020 VISION INITIATIVE
INTERNATIONAL ADVISORY COMMITTEE
H.E.Yoweri K. Museveni (Chairman), President, Republic of Uganda
H.E. Olusegun Obasanjo, President, Federal Republic of Nigeria
Mr. Fawzi Hamad Al-Sultan, Former President, International Fund for Agricultural Development (IFAD), Italy
Mr. Sartaj Aziz, Former Finance Minister and Foreign Minister, Government of Pakistan
Mr. David Beckmann, Director, Bread for the World, USA
Ms. Catherine Bertini, Executive Director,World Food Programme, Italy
Dr. Keith A. Bezanson, Director, Institute of Development Studies, United Kingdom
Mr. Norman E. Borlaug, Distinguished Professor of International Agriculture,Texas A&M University, USA
Dr. Lester Brown, Chairman of the Board of Directors,Worldwatch Institute, USA
Dr. Margaret Catley-Carlson, Chairperson, Global Water Partnership
Prof. Chen Chunming, Senior Advisor and President, Chinese Academy of Preventive Medicine, China
Dr. Gordon R. Conway, President,The Rockefeller Foundation, USA
Dr. Bernd Eisenblätter, Managing Director, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ), Germany
Dr. Leonard Good, President, Canadian International Development Agency (CIDA), Canada
Dr. Bo Göransson, Director General, Swedish International Development Cooperation Agency (SIDA), Sweden
Mr. Michel Griffon, Director, Centre de Coopération Internationale en Recherche Agronomique pour le
Développement (CIRAD), France
Prof. Kenzo Hemmi, Professor Emeritus, University of Tokyo, Japan
Dr. Robert W. Herdt,Vice President,The Rockefeller Foundation, USA
Mr. Dean R. Hirsch, President,World Vision International, USA
Mr. Johan Holmberg, Ambassador of Sweden to Ethiopia
Mr. Ian Johnson, Chairman of the CGIAR and Vice President, Environmentally and Socially Sustainable
Development Network,The World Bank, USA
H.E. Speciosa Wandira Kazibwe,Vice President, Republic of Uganda
Dr. Justin Lin, Professor and Director, China Center for Economic Research, Peking University, China
Mr. Mark Malloch Brown,Administrator, United Nations Development Programme (UNDP), USA
Sra. Margarita Marino de Botero, Corporacion El Colegio Verde, Colombia
Prof.Alexander F. McCalla, Professor Emeritus, University of California at Davis, USA
Mr. Robert S. McNamara, Global Coalition for Africa, USA
Dr. Moïse Mensah, Former Minister of Finance, Government of Benin
H.E. John Evans Atta Mills,Vice President, Republic of Ghana
Sra. D. Cecilia Lopez Montaño, Head, National Planning Department, Colombia
Mr. Harris Mutio Mule, Executive Director,Top Investment and Management Services (TIMS), Limited, Kenya
Dr. Maureen ONeil, President, International Development Research Centre (IDRC), Canada
Prof. David Pimentel, Department of Entomology, Cornell University, USA
Mrs. Mary Robinson, U.N. High Commissioner for Human Rights, Switzerland
Mrs.Victoria Sekitoleko, Regional Representative, Food and Agriculture Organization of the United Nations (FAO),
Zimbabwe
Prof.Amartya Sen,Trinity College, United Kingdom
Dr. Ismail Serageldin, Director, Library of Alexandria, Egypt
Dr. Ammar Siamwalla, President,Thailand Development Research Institute Foundation,Thailand
Dr. M. S. Swaminathan, Chairman, M. S. Swaminathan Research Foundation, India
The Honorable Youssef Wally, Deputy Prime Minister and Minister of Agriculture, Egypt
Mr. Klaus Winkel, Head, Department of Evaluation, Research, and Documentation, Danish International
Development Agency (DANIDA), Denmark
Mr.Timothy Wirth, President, Better World Foundation, USA
Prof. Muhammad Yunus, Managing Director, Grameen Bank, Bangladesh
INTERNATIONAL FOOD
POLICY RESEARCH INSTITUTE
2033 K Street, NW
Washington, DC 20006-1002 USA
Telephone: 001-202-862-5600
Fax: 001-202-467-4439
Email: ifpri@cgiar.org
Website: www.ifpri.org
Also available from the 2020 Vision Initiative:
Rosegrant, Mark W., Ximing Cai, and Sarah A. Cline. 2002. World water and food to 2025: Dealing with scarcity.
IFPRI-2020 Vision/International Water Management Institute book.Washington, D.C. U.S.A.: International
Food Policy Research Institute.
Rosegrant, Mark W., Michael S. Paisner, Siet Meijer, and Julie Witcover. 2001.
2020 Global food outlook:Trends,
alternatives and choices.
2020 Vision Food Policy Report.Washington, D.C., U.S.A.: International Food
Policy Research Institute.
Meinzen-Dick, Ruth S., and Mark W. Rosegrant, eds. 2001.
Overcoming water scarcity and quality constraints.
2020 Vision Focus 9.Washington, D.C., U.S.A.: International Food Policy Research Institute.
ABOUT THE AUTHORS
Mark W. Rosegrant is a senior research fellow in the Environment and Production Technology
Division of the International Food Policy Research Institute (IFPRI) and principal researcher
at the International Water Management Institute (IWMI). Ximing Cai is a research fellow at
IFPRI and a researcher at IWMI. Sarah A. Cline is a research analyst at IFPRI.
... Changes in water extractions in the agro-ecosystem (Shen et al. 2008), alternative approaches for achieving rising water and food demands by 2050 (De Fraiture and Wichelns 2010;De Fraiture et al. 2007), and altering dietary habits affected the water resources. Rosegrant et al. (2002Rosegrant et al. ( , 2009 have been studied together with the links between trends in consumption, trade, social and economic development . To this end, how changes in WF will influence future soil carbon 298 R. Bhatt et al. stock has not been given consideration. ...
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... Changes in water extractions in the agro-ecosystem (Shen et al. 2008), alternative approaches for achieving rising water and food demands by 2050 (De Fraiture and Wichelns 2010;De Fraiture et al. 2007), and altering dietary habits affected the water resources. Rosegrant et al. (2002Rosegrant et al. ( , 2009) have been studied together with the links between trends in consumption, trade, social and economic development (Ercin and Hoekstra 2014). To this end, how changes in WF will influence future soil carbon stock has not been given consideration. ...
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Chapter
Global population is increasing at an alarming rate, need to produce more food grains with the shrieking infinite natural resources, and water security is a major problem on the planet. In the agriculture various level of water pollution due to urbanization, industrialization, changing dietary habits, higher trends of food wastage, etc., its management is a need of hour. In the present scenario reducing the water footprint (WF) for the future generation is a key factor for the society welfare and sustainability on the planet, and agriculture is a big sector that is exploiting the quality water on the earth. There is an urgent need to focus on the ecofriendly water saving approaches with efficient use in the agricultural systems. Rice–wheat cropping system (RWCS) is covering a major area ~12.5 Mha in South Asia; it is using a huge amount of water compared to the other agriculture systems. Scientists across the region are working for reducing the share of the WFs in agriculture and in this regard, many technologies known as resource conservation technologies (RCTs) are advocated in the region. Among different RCTs—laser land levelling (LLL), short duration cultivars, timely transplanting of rice, irrigation scheduling through tensiometers, direct seeding of rice, crop diversification, raised bed planting, mechanical transplanting are the main technologies recommended for the RWCS. Hence, these technologies are not universally effective in reducing the WFs, hence, their proper selection at farmer’s fields in their conditions is a must for reducing the WFs. Further, among all, only two, viz., short period cultivars and appropriate transplanting reduce the drainage (which could be reused) share instead of reducing the share of evaporation (which cannot be reused). Further, as evaporation reduced its reduced share diverted to transpiration which further improves the nutrient inflows and finally yields. This chapter is focused on the integrated invented, tested approaches, those are recommended for the south Asian farmers’, and practicing in the rice-based cropping systems. It can help in reducing the WF to improve the land and water productivity for their livelihoods security.
... Only 3% of all the water on the earth is available as potable water [1]. Furthermore, the need for freshwater has visibly increased during the past few years all over the world [2]. Desalination, which is a process of removing the salts present in water, represents the primary alternative source for freshwater. ...
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Article
In this work, a novel triple-layer nanocomposite membrane prepared with polyethersulfone (PES)/carbon nanotubes (CNTs) as the primary bulk material and poly (vinylidene fluoride-co-hexafluoro propylene) (PcH)/CNTs as the outer and inner surfaces of the membrane by using electrospinning method is introduced. Modified PES with CNTs was chosen as the bulk material of the triple-layer membrane to obtain a high porosity membrane. Both the upper and lower surfaces of the triple-layer membrane were coated with PcH/CNTs using electrospinning to get a triple-layer membrane with high total porosity and noticeable surface hydrophobicity. Combining both characteristics, next to an acceptable bulk hydrophobicity, resulted in a compelling membrane for membrane distillation (MD) applications. The prepared membrane was utilized in a direct contact MD system, and its performance was evaluated in different salt solution concentrations, feed velocities and feed solution temperatures. The results of the prepared membrane in this study were compared to those reported in previously published papers. Based on the evaluated membrane performance, the triple-layer nanocomposite membrane can be considered as a potential alternative with reasonable cost, relative to other MD membranes.
... The World Health Organization concludes that a minimum of 2 L drinking water per person per day is required for an average adult in average conditions [8]. Both water and energy consumption are growing significantly with expected increases of 27% (water) [9] and 30% (energy) [10] by the year 2030. Rooftop solar thermal (e.g. ...
... Of major concern, the cropland expected to be lost to urbanisation is 1.77 times more productive than the global average (d' Amour et al. 2017). Rosegrant et al. (2002) estimated that urban expansion in developing countries decreases cropland by 0.5 million ha/year). Furthermore, urban and peri-urban expansion and rising land values of adjacent lands can diminish the viability of local agricultural production (Naab et al., 2013). ...
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Technical Report
This report examines sustainable land management (SLM) and its potential as an integrative strategy to address multiple environmental and sustainable development objectives. It highlights the linkages between SLM and soil health, land degradation, food security, climate changes mitigation and adaptation. The report is intended to provide information and guidance on fostering SLM, to a wide range of stakeholders involved in agriculture, environmental management and sustainable development. It aims to support investment in SLM by the Global Environment Facility (GEF), particularly investments in pursuit of Land Degradation Neutrality. The report explores the anthropogenic and natural drivers of land degradation, and the potential environmental and socioeconomic benefits of SLM; examines the role of SLM in addressing the critical challenge of global food security; describes the key processes of land degradation and their impacts, as the basis for developing good practice guidance on SLM that is scientifically sound and robust; proposes principles for SLM that promote soil health, productivity and ecosystem services; presents a framework for identifying SLM practices suited to the context and objectives; provides guidance on identifying indicators for evaluation of a site in terms of land potential and soil condition, and indicators for monitoring outcomes of SLM investments; discusses the barriers to adoption of good practice for SLM; and provides recommendations for developing and implementing SLM programs in ways that optimise global environmental benefits. Recommendations are provided to guide investment in support of SLM, and planning of SLM programs. Also available at http://www.stapgef.org/sustainable-land-management-environmental-benefits-and-food-security-synthesis-report-gef
Chapter
This work analyzes some system-wide macroeconomic consequences of lower (sustainable) water availability, when global economic growth is postulated according to the Shared Socio-Economic Pathway 1 (SSP1), for the reference year 2050. After finding that the rather optimistic forecasts of economic development cannot be met in most water scarce macro-regions, we assess what consequences for the structure of the economy, welfare and the terms of trade, the insufficiency of water resources would imply. The analysis is undertaken by means of numerical simulations with a global computable general equilibrium model, under a set of alternative hypotheses. In particular, we consider whether (or not) the regional economic systems have a differentiated capability of adaptation (by means of innovation and modification of economic processes), and whether (or not) the scarce water resources can be allocated among industries, such that more water is assigned where its economic value is greater.
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Conference Paper
Water Balance Study of Beas River (Himachal Pradesh, India) has been presented in this paper. The main objective of this research is to examine the balance water available in the Beas basin (upto Pong Dam) after assessing or delineating the present water utilization including industrial water demand and projected water demand to be satisfied by Beas river (upto Pong Dam). Water resources throughout the world, mainly in India are under very heavy stress due to increased water demand and limited available quantity of water. Sustainable water management of a river basin is essential to ensure a long-term stable and flexible water supply to meet the crop water demands as well as growing municipal and industrial water demands in respected basin. Geographic Information System (GIS) is the most simple and uncomplicated software which assign a management tool for planning of water allocation policies in irrigation system. ArcGIS application permit the users to access information and spatial analysis and produce results in the form of maps, tables and graphs to support the planning and decision making problems. ArcGIS is used for the analysis of various thematic layers, such as flow, basin boundary, and drainage pattern, raingauge station location of Beas Basin (upto pong dam) which comes in four districts of Himachal Pradesh namely Kullu, Mandi, Kangra, and Hamirpur. G&D sites, schemes and anicuts location map were generated by digitization. The raingauge stations in and around Beas river basin (upto pong dam) were considered for analysis. Thiessen polygon is generated using raingauge station points to find out the influencing area and then the influencing factors of each raingauge station. The total water budget of the basin was calculated for the period of 1998-2014 by considering the annual rainfall, which is computed using available rainfall records and the influencing factor of each raingauge station. The total volume of the flow for the above mentioned period was computed using measured discharge data of Beas River at Pong Dam (G&D) site, and is considered for runoff analysis. The rainfall-runoff relation is established. This equation is linear in nature. 75% dependable rainfall is calculated and basin yield is also calculated. Balance water available is-MCM.
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CONTENTS: Brief 1. Overview / Ruth S. Meinzen-Dick and Mark W. Rosegrant Brief 2. Water for Food Production / Mark W. Rosegrant and Ximing Cai Brief 3. Domestic Water Supply, Hygiene, and Sanitation / Hans van Damme Brief 4. Emerging Water Quality Problems in Developing Countries / Wim van der Hoeck - -Brief 5. Water and Rural Livelihoods / Linden Vincent Brief 6. Water and the Environment / Elro Bos and Ger Bergkamp Brief 7. Dams and Water Storage / Jeremy Bird and Pamela Wallace Brief 8. Groundwater: Potential and Constraints / Marcus Moench Brief 9. Water Harvesting and Watershed Management / John Kerr and Ganesh Pangare Brief 10. Water Pricing: Potential and Problems / R. Maria Saleth Brief 11. Markets for Tradable Water Rights / Karin E. Kemper Brief 12. Recognizing Water Rights / Franz and Keebet von Benda-Beckmann Brief 12. Integrated Management of Water in River Basins / Mark Svendsen Brief 13.Water, Conflict, and Cooperation / Aaron T. Wolf
World Water Vision: Making Water Everybody's Business (London:World Water Council and World Water Vision and Earthscan, 2000); I. A. Shiklomanov
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W. J. Cosgrove and F. Rijsberman, World Water Vision: Making Water Everybody's Business (London:World Water Council and World Water Vision and Earthscan, 2000); I. A. Shiklomanov,"Electronic Data Provided to the Scenario Development Panel,World Commission on Water for the 21st Century" (State Hydrological Institute, St. Petersburg, Russia, 1999), mimeo.
Water and the Environment
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E. Bos and G. Bergkamp,"Water and the Environment," in Overcoming Water Scarcity and Quality Contraints, 2020 Focus 9, ed. R. S. Meinzen-Dick and M.W. Rosegrant (Washington, D.C.: International Food Policy Research Institute, 2001).
580 km 3 in the medium Global Change and Global Scenarios of Water Use and Availability:An Application of Water GAP 1.0 (Kassel, Germany: Center for Environmental System Research km 3 in the "business-as-usual" scenario ofElectronic Data
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The global projection is broadly consistent with other recent projections to 2025, including the 4,580 km 3 in the medium scenario of J.Alcamo, P. Döll, F. Kaspar, and S. Sieberg, Global Change and Global Scenarios of Water Use and Availability:An Application of Water GAP 1.0 (Kassel, Germany: Center for Environmental System Research, University of Kassel, 1998), the 4,569 km 3 in the "business-as-usual" scenario of D. Seckler, U.Amarasinghe, D. Molden, S. Rhadika, and R. Barker, World Water Demand and Supply, 1990 to 2025: Scenarios and Issues, Research Report Number 19 (Colombo, Sri Lanka: International Water Management Institute, 1998), and the forecast of 4,966 km 3 (not including reservoir evaporation) of Shiklomanov,"Electronic Data."
World water and food to 2025: Dealing with scarcity. IFPRI-2020 Vision/International Water Management Institute book
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Rosegrant, Mark W., Ximing Cai, and Sarah A. Cline. 2002. World water and food to 2025: Dealing with scarcity. IFPRI-2020 Vision/International Water Management Institute book.Washington, D.C. U.S.A.: International Food Policy Research Institute.
2020 Global food outlook:Trends, alternatives and choices. 2020 Vision Food Policy Report
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Rosegrant, Mark W., Michael S. Paisner, Siet Meijer, and Julie Witcover. 2001. 2020 Global food outlook:Trends, alternatives and choices. 2020 Vision Food Policy Report.Washington, D.C., U.S.A.: International Food Policy Research Institute.