Growing Water Deficit
Threatening Grain Harvests
Analysis by Lester R. Brown
Many countries are facing dangerous water shortages. As
world demand for food has soared, millions of farmers have
drilled too many irrigation wells in efforts to expand their
harvests. As a result, water tables are falling and wells
are going dry in some 20 countries containing half the
The overpumping of aquifers for irrigation temporarily
inflates food production, creating a food production bubble
that bursts when the aquifer is depleted.
The shrinkage of irrigation water supplies in the big three
grain- producing countries - the United States, India, and
China - is of particular concern. Thus far, these countries
have managed to avoid falling harvests at the national
level, but continued overexploitation of aquifers could soon
catch up with them.
In most of the leading U.S. irrigation states, the irrigated
area has peaked and begun to decline. In California,
historically the irrigation leader, a combination of aquifer
depletion and the diversion of irrigation water to
fast-growing cities has reduced irrigated area from nearly
nine million acres in 1997 to an estimated 7.5 million acres
in 2010. (One acre equals 0.4 hectares.)
In Texas, the irrigated area peaked in 1978 at seven million
acres, falling to some five million acres as the Ogallala
aquifer underlying much of the Texas panhandle was depleted.
Other states with shrinking irrigated area include Arizona,
Colorado, and Florida. All three states are suffering from
both aquifer depletion and the diversion of irrigation water
to urban centers. And now that the states that were rapidly
expanding their irrigated area, such as Nebraska and
Arkansas, are starting to level off, the prospects for any
national growth in irrigated area have faded.
With water tables falling as aquifers are depleted under the
Great Plains and California's Central Valley, and with
fast-growing cities in the Southwest taking more and more
irrigation water, the U.S. irrigated area has likely peaked.
India is facing a much more difficult situation. A World
Bank study reported in 2005 that the grain supply for 175
million Indians was produced by overpumping water. Water
tables are falling in several states, including Punjab and
Haryana, two surplus grain producers that supply most of the
wheat and much of the rice used in India's massive food
distribution programme for low-income consumers.
Up-to-date and reliable information is not always easy to
get. But it is clear that overpumping is extensive, water
tables are falling, wells are going dry, and farmers who can
afford to are drilling ever deeper wells in what has been
described as "a race to the bottom".
Based on studies by independent researchers, there is ample
reason to think that decades of overpumping in key states
are leading to aquifer depletion on a scale that is reducing
the irrigation water supply. India's water-based food bubble
may be about to burst.
In China, the principal concern is the northern half of the
country, where rainfall is low and water tables are falling
everywhere. This includes the highly productive North China
Plain, which stretches from just north of Shanghai to well
north of Beijing and which produces half of the country's
wheat and a third of its corn. Overpumping there suggests
that some 130 million Chinese are being fed with grain
produced with the unsustainable use of water.
Furthermore, China's water-short cities and rapidly growing
industrial sector are taking an ever-greater share of the
available surface and underground water resources. In many
situations, growth in urban and industrial demand for water
can be satisfied only by diverting water from farmers.
Although new dams being built in the mountainous southwest
may offset at least some of the losses elsewhere, it is
possible that the irrigated area has peaked in China - and
therefore in all three of the leading grain-producing
Water shortages are most immediately affecting food security
in the Middle East. In 2008, Saudi Arabia became the first
country in the world to acknowledge its bursting food bubble
when it announced that the aquifer supporting its wheat
production was largely depleted. Saudi Arabia is now phasing
out wheat production and could be totally dependent on
foreign grain as soon as 2013.
And in Yemen, water tables are falling by some two metres
per year. The Yemeni grain harvest has shrunk by one third
over the last 40 years, forcing the country to import more
than 80 percent of its grain.
Both Syria and Iraq - the other two populous countries in
the region - have water troubles. Some of these arise from
the reduced flows of the Euphrates and Tigris Rivers, which
both countries depend on for irrigation water. Turkey, which
controls the headwaters of these rivers, is in the midst of
a massive dam building program that is slowly reducing
Although all three countries are party to water-sharing
arrangements, Turkey's ambitious plans to expand both
hydropower and irrigation are being fulfilled partly at the
expense of its two downstream neighbors.
Mindful of the future uncertainty of river water supplies,
farmers in Syria and Iraq are drilling more wells for
irrigation. This is leading to overpumping and an emerging
water-based food bubble in both countries. Syria's grain
harvest has fallen by one fifth since peaking at roughly
seven million tonnes in 2001. In Iraq, the grain harvest has
fallen by one fourth since peaking at 4.5 million tonnes in
Jordan is also on the ropes agriculturally. Forty or so
years ago, it was producing over 300,000 tonnes of grain
annually. Today it produces only 60,000 tonnes and thus must
import over 90 percent of its grain. In Israel, which banned
the irrigation of wheat in 2000 to save water, production of
grain has been falling since 1983. Israel now imports 98
percent of the grain it consumes.
To the east, water supplies are also tightening in Iran and
Afghanistan. An estimated one fifth of Iran's 75 million
people are being fed with grain produced by overpumping,
making its food bubble the largest in the region.
Afghanistan, a landlocked country with a fast-growing
population, is already importing a third of its grain from
Thus in the Middle East, where populations are growing fast,
the world is seeing the first collision between population
growth and water supply at the regional level. Because of
the failure of governments in the region to mesh population
and water policies, each day now brings 10,000 more people
to feed and less irrigation water with which to feed them.
Thus far the countries where shrinking water resources are
actually reducing grain harvests are all ones with smaller
populations. But middle-sized countries such as Pakistan and
Mexico are also overpumping their aquifers to feed growing
Pakistan, struggling to remain self-sufficient in wheat,
appears to be losing the battle. Its population of 185
million in 2010 is projected to reach 246 million by 2025,
which means trying to feed 61 million more people in 15
years. But water levels in wells are already falling by a
meter or more each year around the twin cities of Islamabad
and Rawalpindi. They are also falling under the fertile
Punjab plain, which Pakistan shares with India.
A World Bank report, "Pakistan's Water Economy: Running
Dry", sums up the situation: "The survival of a modern and
growing Pakistan is threatened by water."
In Mexico, home to 111 million people, the demand for water
is outstripping supply. In the agricultural state of
Guanajuato, the water table is falling by six feet or more a
year. In the northwestern wheat-growing state of Sonora,
farmers once pumped water from the Hermosillo aquifer at a
depth of 40 feet. Today, they pump from over 400 feet. With
51 percent of all water extraction in Mexico from aquifers
that are being overpumped, Mexico's food bubble may burst
If business as usual continues, the question for each
country overpumping its aquifers is not whether its food
bubble will burst, but when - and how the government will
cope with it. For some countries, the bursting of the bubble
may well be catastrophic.
And the near-simultaneous bursting of several national food
bubbles could create unmanageable food shortages, posing an
imminent threat to global food security and political
*Adapted from "World on the Edge" by Lester R. Brown,
founder and president of the Earth Policy Institute. Full
book available online at www.earth-policy.org/books/wote..