By Evan Ratliff
The Chinese call it "yellow dragon." Koreans, "the fifth season." Each
spring, the dust from China's northern deserts is swept up by the wind and
whipped eastward, blasting into Beijing. A choking blanket of particles
coats houses, cars, and people, and the city's hospitals become flooded with
patients suffering from respiratory ailments.
The dust clogs machinery, shutters airports, and destroys crops,
forcing thousands of rural Chinese off their lands. Clouds of it blow
throughout Asia, carrying pollution and potentially infectious disease. In
Korea, the government recently considered declaring the dust storms a
natural disaster. The furies are fed by desertification: Overgrazing,
deforestation, and drought convert arid land to desert, creating a layer of
mobile topsoil.

This combination of forces is expanding the Gobi desert by about 950
square miles per year - an area two-thirds the size of Rhode Island. Now,
with the dunes within 150 miles of China's capital city, and the 2008
Olympics on the way, Beijing officials have initiated a massive campaign to
attack the problem.

The plan is known as the Green Great Wall - a 2,800-mile network of
forest belts designed to stop the sands. Chinese scientists from the
Ministry of Forestry believe the trees can serve as a windbreak and halt the
advancing desert. In a recent report to the United Nations, Chinese
officials predicted that the effort will "terminate expansion of new
desertification caused by human factors" within a decade. By 2050, they
claim, much of the arid land can be restored to a productive and sustainable
state.

Possibly the largest proposed ecological project in history, the new
Great Wall calls for planting more than 9 million acres of forest at a cost
of up to $8 billion. The project began last year as the fourth phase of an
afforestation program launched in 1978. By 2010, the green belts are
expected to stretch from outer Beijing through Inner Mongolia. To build the
wall, the government has launched a two-pronged plan: Use aerial seeding to
cover wide swaths of land where the soil is less arid, and pay farmers to
plant trees and shrubs in areas that require closer attention. A $1.2
billion oversight system, consisting of mapping and land-surveillance
databases, will be implemented. The government has also hammered out a
dust-monitoring network with Japan and Korea.

The wall itself will be made up of an outer belt - ranging from 775 to
1,765 feet wide - with a sand fence along the perimeter. Inside, low-lying,
sand-tolerant vegetation, arranged in optimized checkerboard patterns, will
create an artificial ecosystem to stabilize the dunes. A 6-foot-wide gravel
platform will hold sand down and encourage a soil crust to form. The
government has also funded research to explore the use of genetically
engineered plants, chemical dune stabilization, grass strains bred in space,
and even farming techniques that will allow rice to grow in sandy soil.

Can an expansive row of trees and some strategically placed grass
really stave off an encroaching desert? It worked before. In 1935,
overgrazing and drought caused 850 million tons of topsoil to blow off the
United States' southern Plains, leaving 4 million acres barren and creating
the Dust Bowl. To address the problem, the newly formed Soil Conservation
Service introduced the Shelterbelt Project - a 100-mile-wide strip of native
trees bisecting the country from Canada to Texas. In a few years, it helped
to reduce the amount of airborne soil by 60 percent.

But in China, the question remains as to whether the area targeted by
the wall is just too arid to support trees. And even if the trees do take
root, they'll soak up massive amounts of groundwater, which could worsen the
problem. "You may improve one part of the landscape," says Hong Jiang, a
geography professor at the University of Wisconsin, "but you can't hold back
the degradation."

Ultimately, many Western scientists fear that the Green Great Wall is
an expensive band-aid on a centuries-old wound. Or worse, propaganda. Either
way, Dee Williams, a US Department of Interior anthropologist who has
cataloged the failure of past anti-desertification efforts in China, argues
that the country must move beyond micro-level tech fixes and embrace
political solutions. The government needs to foster positive behavior - pay
farmers to reduce livestock numbers, raise water prices to encourage
conservation, and temporarily relocate locals away from arid areas to allow
recovery. The last hope, says Williams, is that the choking dust will force
the government to act. "Maybe it takes a crisis to precipitate the kind of
creative thinking the Chinese are capable of," he says.

With the dust storms intensifying, the success or failure of the wall
will have an effect beyond China's backyard. Last year, Pacific winds blew
dust plumes all the way to North America, causing spectacular sunsets off
San Francisco. But in the future, the result could be far less beautiful.
Toxins picked up over Asia's urban centers hitch a ride on dust particles,
creating a global highway for air pollution. China is hoping that the Great
Green Wall will begin working some magic before that happens - and prevent
an international dustup.

10 years of environmental engineering

1996
Italian army blows up 15,000 pounds of explosives to block lava
flowing from Mount Etna to villages below.

1999
Mexico City installs 20,000 air filters on streetlights in the
smog-choked central district.

US approves an $8 billion project to rechannel a river as part of
reengineering the 4 million-acre Florida Everglades.

Los Angeles builds a massive ground-based sprinkler system to control
dust pollution in nearby Owens Valley.

2001
New York City Transit dumps some 1,000 subway cars in the ocean off
Delaware and South Carolina to serve as artificial reefs.

2002
Construction begins on Italy's $3 billion plan to build hinged dams
around Venice to keep the city from sinking.

2003
First generators go online at China's Three Gorges Dam, a $24 billion
project that will provide 18.2 million kilowatts of power by 2009.

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