This article is from World Watch regarding China's Water Shortage.
An unexpectedly abrupt
decline in the supply of water for China's
farmers poses a rising threat to world food security. China depends
on
irrigated land to produce 70 percent of the grain for its huge
population of 1.2 billion people, but it is drawing more and more
of
that water to supply the needs of its fast-growing cities and
industries. As rivers run dry and aquifers are depleted, the emerging
water shortages could sharply raise the country's demand for grain
imports, pushing the world's total import needs beyond exportable
supplies.
Any major threat to China's food self-sufficiency, if not addressed
by
strong new measures, would likely push up world grain prices,
creating
social and political instabilities in Third World cities-as previous
WORLD WATCH articles have pointed out (see commentary). New information
on the deteriorating water situation has confirmed the imminence
of this
possibility. The challenge now facing the Chinese government is
how to
meet the soaring water needs of its swelling urban and industrial
sectors without undermining both its own agriculture and the world's
food security.
The decline in China's capacity to irrigate its crops-signs
of which
include the drying-up of rivers and wells all over the northern
region
of the country-is coming at a time when depleted world grain stocks
are
near an all-time low. With its booming economy and huge trade
surpluses,
China can survive its water shortages by simply importing more
of its
food, because it can afford to pay more for grain. But low-income
countries with growing grain deficits may not be able to pay these
higher prices. For the 1.3 billion of the world's people who live
on $1
a day or less, higher grain prices could quickly become life
threatening. The problem is now so clearly linked to global security
that the U.S. National Intelligence Council (NIC) the umbrella
over all
U.S. intelligence agencies, has begun to monitor the situation
with the
kind of attention it once focused on Soviet military maneuvers.
This deepening concern led the NIC to sponsor a major interdisciplinary
assessment of China's food prospect. Headed by Michael McElroy,
chairman
of Harvard University's Department of Earth and Planetary Sciences,
the
study used information from intelligence satellites to refine
cropland
area estimates, and commissioned computer modeling by the Sandia
National Laboratory to assess the extent of future water shortages
in
each of China's river basins. The recently released study concluded
that
China will need massive grain imports in the decades ahead-a conclusion
that meshes with earlier projections published by WORLD WATCH.
Signs of Stress
SINCE MID-CENTURY, the population of China has grown by nearly
700
million-an increase almost equivalent to adding the whole population
of
the world at the beginning of the Industrial Revolution. Most
of that
population has concentrated in the region through which several
great
rivers, including the Yellow and the Yangtze, flow. Those rivers
provide
the irrigation water needed to grow much of the food for China,
as well
as the water for its burgeoning cities and industries.
This dependence has placed a growing burden on the region's
land and
water resources, because the Chinese population has not been able
to
expand into new land the way the Americans once did with their
westward
expansion into the Great Plains and California. In China, the
western
half of the country is mostly desert or mountains. The resulting
concentration of Chinese population, industry, and agriculture
has been
roughly equivalent to squeezing the entire U.S. population into
the
region east of the Mississippi, then multiplying it by five.
A quarter-century ago, with more and more of its water being
pumped out
for the country's multiplying needs, the Yellow River began to
falter.
In 1972, the water level fell so low that for the first time in
China's
long history it dried up before reaching the sea. It failed on
15 days
that year, and intermittently over the next decade or so. Since
1985, it
has run dry each year, with the dry period becoming progressively
longer. In 1996, it was dry for 133 days. In 1997, a year exacerbated
by
drought, it failed to reach the sea for 226 days. For long stretches,
it
did not even reach Shandong Province, the last province it flows
through
en route to the sea. Shandong, the source of one-fifth of China's
corn
and one-seventh of its wheat, depends on the Yellow River for
half of
its irrigation water.
Although it is perhaps the most visible manifestation of water
scarcity
in China, the drying-up of the Yellow River is only one of many
such
signs. The Huai, a smaller river situated between the Yellow and
Yangtze, was also drained dry in 1997, and failed to reach the
sea for
90 days. Satellite photographs show hundreds of lakes disappearing
and
local streams going dry in recent years, as water tables fall
and
springs cease to flow. As water tables have fallen, millions of
Chinese
farmers are finding their wells pumped dry.
In the geography of water, there are two Chinas. The humid
south
includes the vast Yangtze River and a population of 700 million.
The
arid north includes the Yellow, Liao, Hai, and Huai Rivers, and
has 550
million. While four-fifths of the water is in the south, two-thirds
of
the cropland is in the north. As a result, the water per hectare
of
cropland in the north is only one-eighth that in the south.
Although comprehensive hydrological data are not always available,
key
pieces of the water puzzle are beginning to emerge from various
sources.
A recent Chinese survey reported by Professor Liu Yonggong of
China
Agricultural University in Beijing indicated that the water table
beneath much of the North China Plain, a region that produces
some 40
percent of China's grain, has fallen an average of 1.5 meters
(roughly 5
feet) per year over the last five years. A joint Sino-Japanese
analysis
of China's agricultural prospect reports that water tables are
falling
almost everywhere in China that the land is flat.
In the late summer of 1997, many of the irrigation wells in
Shandong
Province, which was experiencing its worst drought in 25 years,
were not
pumping. Chinese water analysts report frenzied well-drilling
in some
provinces as farmers chased the falling water table downward.
Of course, those farmers' ability to provide food enough for
their
nation is constrained by a range of factors in addition to water-by
the
construction of roads over once-productive farmland, by erosion
of soil,
by the diminishing benefits of fertilizer, and by a shrinking
backlog of
the technology used to raise land productivity. But it is the
swelling
diversion of irrigation water, combined with heavy losses to aquifer
depletion, that has emerged as the most imminent threat to China's
food
security.
Projected Demand for Water
EVEN AS THE YELLOW RIVER, aquifers, and wells get drier, the
amount of
water needed continues to swell. Between now and 2030, UN demographers
project that China's population will increase from 1.2 billion
to 1.5
billion, an increase that exceeds the entire population of the
United
States. Even if there were no changes in water consumption per
person,
this would boost the demand for water by one fourth above current
levels-but per-person consumption, too, is growing. It is expected
to
grow in all three of the end use sectors-agricultural, residential,
and
industrial.
In the agricultural sector, demand for irrigation water, now
roughly 400
billion cubic meters or tons per year, is expected to reach 665
billion
tons in 2030. As incomes rise, people are consuming more pork,
poultry,
beef, and eggs, and feedgrain use is growing. For example, to
produce
one kilogram of pork it takes four kilograms of grain, and one
kilogram
of chicken takes two kilograms of grain. More grain means more
water
(see Figure 1). Between 1990 and 1997, consumption of pork climbed
by a
phenomenal 9 percent per year. Consumption of both beef and poultry,
starting from a much smaller base, has climbed at over 20 percent
per
year. The brewing of beer, which is also made from grain, is growing
at
7 percent annually.
In the residential sector, a similar compounding is occurring.
At
present, some 85 percent of all water withdrawals are for irrigation,
but the residential share is increasing as China's population
urbanizes
and hundreds of millions turn from the village well to indoor
plumbing
with showers and flush toilets. Combined with projected increases
in
population, rising individual water use will boost residential
water use
from 31 billion tons in 1995 to 134 billion tons in 2030, a gain
of more
than four-fold.
The demand for water by industry is growing even faster. Assuming
an
economic growth of 5 percent a year from 1995 until 2030 (actual
growth
in the past decade has been more than twice that rate), industrial
water
use would increase from 52 billion tons to 269 billion tons (see
table).
The increase in residential and industrial water use together
would
total 320 billion tons of water during this 25-year span. If this
water
were used for irrigation, at 1,000 tons of water required per
ton of
grain produced, it would yield 320 million tons of grain, an amount
approaching China's 1997 grain harvest of 380 million tons.
In other words, non-agricultural uses that are now straining
the system
by drawing only 15-percent of the supply would multiply nearly
five
times, while the agricultural needs now taking 85 percent would
have
increased as well. Obviously, that can't happen. Because consumption
can't exceed the sustainable supply for long, China is facing
fundamental changes in the way it distributes and uses its water.
Diversion, Depletion, and Pollution
THOUGH 70-PERCENT OF THE GRAIN produced in China comes from
irrigated
land, the country is seeing its irrigation supply depleted on
three
fronts: the diversion of water from rivers and reservoirs to cities;
the
depletion of underground supplies in aquifers; and the increasing
pollution caused by rapid industrialization. Politically, it is
difficult for any government to deny people water for their showers
and
toilets, if they can afford to buy it-and China's urbanizing population
increasingly can. And economically, farms can't compete with factories
for water. As competition among farms, homes, and industries
intensifies, farms inevitably lose out.
Of China's 617 cities, 300 are already facing water shortages.
In those
areas of north China where all available water is being used,
these
shortfalls can be filled only by diverting water from agriculture.
In
the spring of 1994, farmers in the region surrounding Beijing
were
denied access to reservoirs, their traditional source of irrigation
water, because all the water was needed to satisfy the city's
burgeoning
demand. That established a pattern for water-stressed cities all
over
the north North China Plain
As for the demand from industry, agriculture simply cannot
compete in
China or anywhere else. A thousand tons of water produces one
ton of
wheat, which has a market value of $200, whereas the same amount
of
water used in industry yields an estimated $14,000 of output-70
times as
much. Moreover, that economic advantage is reinforced by a political
one: the need to provide jobs for some 14 million new entrants
into the
labor force each year. And, as China's old state-run corporations
are
cut back, massive layoffs are leaving millions of people unemployed.
As
it happens, water used in industry can also create a disproportionately
large number of jobs. Since incomes are much higher in industry
than in
agriculture, the number of jobs a given amount of water can bring
to
industry versus agriculture is somewhat less than the 70 to 1
just
mentioned, but the bottom line still is that shifting irrigation
water
to industry creates many more jobs.
While farmers are losing out to cities and industries politically,
they
are also losing ground hydrologically. As the demand for underground
water increases over time, the pumping eventually surpasses the
natural
recharge of the aquifer, which comes from precipitation in the
upstream
portion of the watershed. After this "sustainable yield threshold"
is
passed, the water table starts to fall. If demand continues to
climb,
the excess of pumping over the sustainable yield of the aquifer
widens
each year. As a result, the distance the water table falls increases
each year.
Once the aquifer is depleted, the amount of water pumped is
limited to
the rate of recharge. It cannot be otherwise. If the pumping has
been
taking place at double the recharge when depletion occurs, then
the
pumping will be cut by half. If pumping has been five times the
recharge, it will be cut by four fifths. Under the North China
Plain, if
the water table is falling 1.5 meters per year, then the pumping
could
easily be occurring at double the recharge rate. And if it is,
the time
will come when the amount of water pumped in this wheat and corn
belt
will be necessarily cut by half.
When farmers lose irrigation water, they either revert to rainfed
farming if rainfall is sufficient or they abandon the land if
it is not.
For China, most of the land will simply revert to rainfed agriculture.
The yield will then decline by about one-half to two-thirds.
Unfortunately, even this stark arithmetic fails to fully convey
the
extent to which China's grainland irrigation water is being lost,
because it doesn't account for losses to pollution. There are
50,000
kilometers of major rivers in China, and, according to the UN
Food and
Agriculture Organization, 80 percent of them are so degraded they
no
longer support fish. As a result of toxic discharge from cities
and
upstream enterprises, which include such highly polluting industries
as
paper mills, tanneries, oil-refineries and chemical plants, the
Yellow
River water is now loaded with heavy metals and other toxins that
make
it unfit even for irrigation, much less for human consumption,
along
much of its route.
Water pollution horror stories abound throughout China as farmers-for
want of a cleaner source-irrigate with heavily polluted water.
In Shanxi
province, in the Yellow River watershed, rice has been found to
contain
excessive levels of chromium and lead, and the cabbage is laced
with
cadmium. Along the length of the Yellow River, abnormally high
rates of
mental retardation, stunting and developmental diseases are linked
to
elevated concentrations of arsenic and lead in the water and food.
As industrialization outpaces pollution control, more and more
river
water is rendered unsuitable for irrigation. In the heavily
industrialized, heavily populated Yangtze valley, it may not be
the
diversion of water to industry that most threatens agriculture,
but the
pollution of water by industry, which renders it unsuitable for
irrigation to begin with.