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Copyright © 2002 Earth Policy Institute
Water Scarcity Spreading
Lester Brown
Water scarcity may be the most underestimated
resource issue facing the world today. As world water demand has
more than tripled over the last half-century, signs of water scarcity
have become commonplace. Some of the more widespread indicators
are rivers running dry, wells going dry, and lakes disappearing.
Among the rivers that run dry for part of the year are the Colorado
in the United States, the Amu Darya in Central Asia, and the Yellow
in China. China's Hai and Huai rivers have the same problem from
time to time, and the flow of the Indus River—Pakistan's
lifeline—is sometimes reduced
to a trickle when it enters the Arabian Sea.
The Colorado River, the largest in the southwestern United States,
now rarely makes it to the sea. As the demand for water increased
over the years, diversions from the river have risen to where they
now routinely drain it dry.
A similar situation exists in Asia, where the Amu Darya—one
of the two rivers feeding the Aral Sea—now
is dry for part of each year. With the sharp decline in the amount
of water delivered to the Aral Sea by the Amu Darya, the sea has
begun to shrink. There is a risk that the Aral could one day disappear
entirely, existing only on old maps.
China's Yellow River, the northernmost of its two major rivers,
first ran dry for a few weeks in 1972. Since 1985, it has failed
to make it to the Yellow Sea for part of almost every year. Sometimes
the river does not even reach Shandong, the last province it flows
through en route to the sea. As water tables have fallen, springs
have dried up and some rivers have disappeared entirely. China's
Fen River, the major watercourse in Shanxi Province, which once
flowed through the capital of Taiyuan and merged with the Yellow,
no longer exists.
Another sign of water scarcity is disappearing lakes. In Central
Africa, Lake Chad has shrunk by some 95 percent over the last four
decades. Reduced rainfall, higher temperatures, and some diversion
of water from the streams that feed Lake Chad for irrigation are
contributing to its demise. In China, almost 1,000 lakes have disappeared
in Hebei Province alone.
Water tables are falling in several of the world's key farming regions,
including under the North China Plain, which produces nearly one
third of China's grain harvest; in the Punjab, which is India's
breadbasket; and in the U.S. southern Great Plains, a leading grain-producing
region.
Water shortages now plague almost every country in North Africa
and the Middle East. Algeria, Egypt, Iran, and Morocco are being
forced into the world market for 40 percent or more of their grain
supply. As population continues to expand in these water-short nations,
dependence on imported grain is rising.
Iran, one of the most populous countries in the Middle East, with
70 million people, is facing widespread water shortages. In the
northeast, Chenaran Plain—a fertile
agricultural region to the east of Mashad, one of Iran's largest
and fastest-growing cities—is
fast losing its water supply. Wells drawing from the water table
below the plain are used for irrigation and to supply water to Mashad.
The latest official estimate shows the water table falling by 8
meters in 2001 as the demand for water far outstrips the recharge
rate of aquifers.
Falling water tables in parts of eastern Iran have caused many wells
to go dry. Some villages have been evacuated because there is no
longer any accessible water. Iran is one of the first countries
to face the prospect of water refugees—people
displaced by the depletion of water supplies.
In Yemen, a country of some 19 million people, water tables are
falling everywhere by 2 meters or more a year. In the basin where
the capital Sana'a is located, extraction exceeds recharge by a
factor of five, dropping the water table by 6 meters (about 20 feet)
a year. Recent wells drilled to a depth of 2 kilometers (1.3 miles)
failed to find any water. In the absence of new supplies, the Yemeni
capital will run out of water by the end of this decade.
Another way of looking at water security is the amount of water
available per person in a country. In 1995, 166 million people lived
in 18 countries where the average supply of fresh water was less
than 1,000 cubic meters a year—the
amount deemed necessary to satisfy basic needs for food, drinking
water, and hygiene. By 2050, water availability per person is projected
to fall below the 1,000-cubic-meter benchmark in some 39 countries.
By then, 1.7 billion people will in effect be suffering from hydrological
poverty.
At some point, the combination of aquifer depletion and the diversion
of irrigation water to cities will likely begin to reduce the irrigated
area worldwide. Data compiled by the U.N. Food and Agriculture Organization,
based on official data submitted by governments, show irrigated
area still expanding. For example, between 1998 and 1999, the last
year for which global data are available, irrigated area grew from
271 to 274 million hectares. (See Figure.) This reported 1-percent
growth would be reassuring, but it appears to be overstated since
governments are much better at gathering data on new irrigation
projects than on irrigation reductions as water is diverted to cities
or aquifers are depleted. It is quite possible that the historical
growth in world irrigated area has come to a halt, and the area
could even be declining.
Copyright
© 2002
Earth Policy Institute
Figure
1: World Irrigated Area and Irrigated Area Per Person, 1961-1999
Figure
2: Selected Examples
of Aquifer Depletion Worldwide
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DATA
Figure
1: World Irrigated Area and Irrigated Area Per Person, 1961-1999
Figure
2: Selected Examples
of Aquifer Depletion Worldwide
OTHER INFORMATION FROM THE EARTH POLICY
INSTITUTE
ECO-ECONOMY
UPDATES:
Rising Temperatures
and Falling Water Tables Raising Grain Prices
Water Deficits
Growing in Many Countries
World Grain Harvest
Falling Short by 54 Million Tons: Water Shortages Contributing to
Shortfall
Worsening Water
Shortages Threaten China's Food Security
BOOKS
Lester R. Brown, Janet Larsen, and Bernie Fischlowitz-Roberts,
The Earth Policy Reader
(New York: W.W. Norton & Company, 2002).
Lester R. Brown, Chapter 2: "Signs of Stress: Climate
and Water," in Eco-Economy:
Building an Economy for the Earth (W.W. Norton & Company,
2001).
LINKS
AQUASTAT, global information system of water and
agriculture from the Land and Water Development Division of the
U.N. Food and Agriculture Organization
http://www.fao.org/ag/
agl/
aglw/aquastat/
main/index.stm
International Water Management Institute
http://www.cgiar.org/iwmi
The World's Water
http://www.worldwater.org
United Nations Environment Programme, UNEP Freshwater
Site
http://freshwater.unep.net
Worldwatch Institute, Water Mini Site
http://www.worldwatch.org/
taxonomy/term/102
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