abbassamento delle falde acquifere in Cina ..

["AlessandroGimona"<agimona at libero.it>]

Dal World Watch Institute:


FALLING WATER TABLES IN CHINA MAY SOON RAISE FOOD PRICES EVERYWHERE
Lester R. Brown
In 1999 the water table under Beijing fell by 2.5 meters (8 feet).  
Since 1965, the water table under the city has fallen by some 59 meters 
or nearly 200 feet, warning China's leaders of the shortages that lie 
ahead as the country's aquifers are depleted.
Hydrologically, there are two Chinas-the humid south, which includes the 
Yangtze River basin and everything south of it, and the north, which 
includes all the country north of the Yangtze basin. The south, with 700 
million people, has one third of the nation's cropland and four fifths 
of its water. The north, with 550 million people, has two thirds of the 
cropland and one fifth of the water.
The water per hectare of cropland in the north is one eighth that of the 
south.
The northern part of the country is drying out as the demand for water 
outstrips the supply. Water tables are falling. Wells are going dry. 
Streams are drying up, and rivers and lakes are disappearing.  Under the 
North China Plain, a region that stretches from just north of Shanghai 
to well north of Beijing and that produces 40 percent of China's grain, 
the water table is dropping by an average of 1.5 meters per year.
Farmers in the north are faced with losses of irrigation water both from 
aquifer depletion and from the diversion to cities and industry.  
Between now and 2010, when China's population is projected to grow by 
126 million, the World Bank projects that the nation's urban water 
demand will increase from 50 billion cubic meters to 80 billion, a 
growth of 60 percent. Industrial water demand, meanwhile, is projected 
to increase from 127 billion cubic meters to 206 billion, an expansion 
of 62 percent. In much of northern China, this growing demand for water 
can be satisfied only by taking irrigation water from agriculture.
What happens to irrigation water supplies directly affects China's 
agricultural prospect.  Whereas les
percent of the U.S.  grain 
harvest comes from irrigated land, in China it is close to 70 percent.
In the competition for water between cities, industry, and agriculture, 
the economics of water use do not favor agriculture. In China, a 
thousand tons of water produces one ton of wheat, worth perhaps $200.  
The same water used in industry will expand output by $14,000-70 times 
as much. In a country that is desperately seeking economic growth and, 
even more, the jobs it generates, the gain in diverting water from 
agriculture to industry is obvious.
The Yellow River, the northernmost of the country's two major rivers, is 
being overused. After flowing uninterruptedly for thousands of years, 
this cradle of Chinese civilization ran dry in 1972, failing to reach 
the sea for some 15 days.  In the following years, it ran dry 
intermittently until 1985. Since then, it has run dry for part of each 
year. In 1997, a drought year, the Yellow River failed to reach the sea 
for 226 days.
In fact, during much of 1997 the river failed to reach Shandong 
Province, the last of the eight it flows through en route to the sea.  
Shandong, producing a fifth of China's corn and a seventh of its wheat, 
is more important to China than are Iowa and Kansas together to the 
United States. Half of the province's irrigation water used to come from 
the Yellow River, but this supply is now shrinking. The other half comes 
from an aquifer that is falling by 1.5 meters per year.
As more and more water is diverted to industry and cities upstream, less 
is available downstream. Beijing is permitting the poverty-ridden 
upstream provinces to divert water for their development at the expense 
of agriculture in the lower reaches of the basin.
Among the hundreds of projects to divert water from the Yellow River in 
the upper reaches is a canal that will take water to Hohhot, the capital 
of Inner Mongolia, starting in 2003. This additional water wi ll help 
satisfy swelling residential needs as well as those of ex

industries, including the all-important wool textile industry that is 
supplied by the region's vast flocks of sheep.  Another canal will 
divert water to Taiyuan, the capital city of Shanxi province, a city of 
some 4 million that has recently been forced to ration water.
The growing upstream claims on the Yellow River mean that one day it may 
no longer reach Shandong Province at all, depriving the province of 
roughly half of its irrigation water. The resulting prospect of massive 
grain imports and growing dependence on U.S. grain leads to sleepless 
nights for political leaders in Beijing.
Immediately to the north of the Yellow River basin is the Hai River 
basin, which has over 100 million people and includes Beijing and 
Tianjin, both large industrial cities. Water use in the basin currently 
totals 55 billion cubic meters annually, while the sustainable supply 
totals only 34 billion cubic meters. This annual deficit of 21 billion 
cubic meters is being satisfied largely by groundwater mining-by 
overpumping. Once the aquifer is depleted, water pumping will 
necessarily drop to the sustainable yield, cutting the water supply by 
nearly 40 percent. Given rapid urban and industrial growth in the area, 
irrigated agriculture in the basin could largely disappear by 2010, 
forcing a shift back to less productive rainfed agriculture.
Meanwhile, as China's economy expands at a projected annual rate of 7 
percent, as it adds 12 million people a year, and as Chinese eat more 
grain-fed meat, the country's need for grain will continue to grow.  
This, coming at a time when grain production will be falling in key 
producing regions as water shortages intensify, could quickly make China 
the world's leading grain importer, overtaking even Japan.
Water shortages can be ameliorated by using water more efficiently, but 
in China this is not always easy. A recent government strategy paper 
indicates that this means raising water prices to an "appropriate" 
level, one much closer to market v
 with political risks because the public response to raising 
water prices in China is akin to that of raising gasoline prices in the 
United States.
Recent policy decisions indicate the direction in which China is 
planning to move.  For one, China has officially abandoned its 
longstanding policy of grain self-sufficiency. After raising the grain 
support price some 42 percent in 1994 in a valiant effort to remain 
self-sufficient, the leaders in Beijing have since acknowledged that the 
fiscal cost was too high, and they are permitting the price of grain to 
fall toward world market levels.  They have also announced that in the 
competition for water, cities and industry get priority-leaving 
agriculture last.
China is not alone in facing water shortages. Other countries where 
water scarcity is raising grain imports or threatening to do so include 
India, Pakistan, Iran, Egypt, Mexico, and dozens of smaller countries. 
But only China-with nearly 1.3 billion people, a fast-growing economy, 
and a $40-billion-plus trade surplus with the United States-has the 
potential to disrupt world grain markets. In short, falling water tables 
in China could soon mean rising food prices for the entire world.
CONTACT: Reah Janise Kauffman
Worldwatch Institute
1776 Massachusetts Ave., NW
Washington, DC   20036-1904
PHONE: (202) 452-1992 x 514
FAX: (202) 296-7365
EMAIL: rjkauffman at worldwatch.org