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[a-w-h] Windpower in North China, to relieve a developing Dust-Bowl. by David MacClement 24 May 2001 03:55 UTC |
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· Some of you, with roots in the west-central US, will shudder to read
about what's been happening in northern China in recent years. (My 21yo
daughter lived on her own in Beijing through the winter and spring of 1999
- I've just checked a Mar 25 e-mail titled "still alive" - she told me
about the dust then.)
· But the reason I'm posting this to a Wind-Energy group is because it
suggests using windturbines to take enough energy out of the wind near the
soil surface that much less of the soil is blown away.
Here's the main bit:
"Official estimates show 900 square miles (2,330 square kilometers) of
land going to desert each year."
".. another interesting option now presents itself—the use of wind
turbines as windbreaks to reduce wind speed and soil erosion. With the cost
of wind-generated electricity now competitive with that generated from
fossil fuels, constructing rows of wind turbines in strategic areas to slow
the wind could greatly reduce the erosion of soil. This also affords an
opportunity to phase out the use of wood for fuel, thus lightening the
pressure on forests.
The economics are extraordinarily attractive. In the U.S. Great Plains,
under conditions similar to China's northwest, a large advanced-design wind
turbine occupying a tenth of a hectare of land can produce $100,000 worth
of electricity per year. This source of rural economic regeneration fits in
nicely with China's plan to develop the impoverished northwest.
Reversing desertification will require a huge effort .."
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...
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EARTH POLICY ALERT
Alert 2001-2
For Immediate Release
May 23, 2001
Copyright Earth Policy Institute 2001
DUST BOWL THREATENING CHINA'S FUTURE
Lester R. Brown
On April 18, scientists at the National Oceanic and Atmospheric
Administration (NOAA) laboratory in Boulder, Colorado, reported that a huge
dust storm from northern China had reached the United States "blanketing
areas from Canada to Arizona with a layer of dust." They reported that
along the foothills of the Rockies the mountains were obscured by the dust
from China.
This dust storm did not come as a surprise. On March 10, 2001, The
People's Daily reported that the season's first dust storm—one of the
earliest on record—had hit Beijing. These dust storms, coupled with those
of last year, were among the worst in memory, signaling a widespread
deterioration of the rangeland and cropland in the country's vast northwest.
These huge dust plumes routinely travel hundreds of miles to populous
cities in northeastern China, including Beijing, obscuring the sun,
reducing visibility, slowing traffic, and closing airports. Reports of
residents in eastern cities caulking windows with old rags to keep out the
dust are reminiscent of the U.S. dust bowl of the 1930s. Eastward moving
winds often carry soil from China's northwest to North Korea, South Korea,
and Japan, countries that regularly complain about dust clouds that both
filter out the sunlight and cover everything with dust. Responding to
pressures from their constituents, a group of 15 legislators from Japan and
8 from South Korea are organizing a tri-national committee with Chinese
lawmakers to devise a strategy to combat the dust.
News reports typically attribute the dust storms to the drought of the
last three years, but the drought is simply bringing a fast-deteriorating
situation into focus. Human pressure on the land in northwestern China is
excessive. There are too many people, too many cattle and sheep, and too
many plows. Feeding 1.3 billion people, a population nearly five times that
of the United States, is not an easy matter.
In addition to local pressures on resources, a decision in Beijing in
1994
to require that all cropland used for construction be offset by land
reclaimed elsewhere has helped create the ecological disaster that is now
unfolding. In an article in Land Use Policy, Chinese geographers Hong Yang
and Xiubein Li describe the environmental effects of this offset policy.
The fast-growing coastal provinces, such as Guandong, Shandong, Xheijiang,
and Jiangsu, which are losing cropland to urban expansion and industrial
construction, are paying other provinces to plow new land to offset their
losses. This provided an initial economic windfall for provinces in the
northwest, such as Inner Mongolia (which led the way with a 22-percent
cropland expansion), Gansu, Qinghai, Ningxia, and Xinjiang.
As the northwestern provinces, already suffering from overplowing and
overgrazing, plowed ever more marginal land, wind erosion intensified. Now
accelerating wind erosion of soil and the resulting land abandonment are
forcing people to migrate eastward, not unlike the U.S. westward migration
from the southern Great Plains to California during the Dust Bowl years.
While plows are clearing land, expanding livestock populations are
denuding the land of vegetation. Following economic reforms in 1978 and the
removal of controls on the size of herds and flocks that collectives could
maintain, livestock populations grew rapidly. Today China has 127 million
cattle compared with 98 million in the United States. Its flock of 279
million sheep and goats compares with only 9 million in the United States.
In Gonge County in eastern Quinghai Province, the number of sheep that
local grasslands can sustain is estimated at 3.7 million, but by the end of
1998, sheep numbers there had reached 5.5 million, far beyond the land's
carrying capacity. The result is fast-deteriorating grassland,
desertification, and the formation of sand dunes.
In the New York Times, Beijing Bureau Chief Erik Eckholm writes that
"the
rising sands are part of a new desert forming here on the eastern edge of
the Quinghai-Tibet Plateau, a legendary stretch once known for grass
reaching as high as a horse's belly and home for centuries to ethnic
Tibetan herders." Official estimates show 900 square miles (2,330 square
kilometers) of land going to desert each year. An area several times as
large is suffering a decline in productivity as it is degraded by overuse.
In addition to the direct damage from overplowing and overgrazing, the
northern half of China is literally drying out as rainfall declines and
aquifers are depleted by overpumping. Water tables are falling almost
everywhere, gradually altering the region's hydrology. As water tables
fall, springs dry up, streams no longer flow, lakes disappear, and rivers
run dry. U.S. satellites, which have been monitoring land use in China for
some 30 years, show that literally thousands of lakes in the North have
disappeared.
Deforestation in southern and eastern China is reducing the moisture
transported inland from the South China Sea, the East China Sea, and the
Yellow Sea, writes Wang Hongchang, a Fellow at the Chinese Academy of
Social Sciences. Where land is forested, the water is held and evaporates
to be carried further inland. When tree cover is removed, the initial
rainfall from the inland-moving, moisture-laden air simply runs off and
returns to the sea. As this recycling of rainfall inland is weakened by
deforestation, rainfall in the interior is declining.
Reversing this degradation means stabilizing population and planting
trees
everywhere possible to help recycle rainfall inland. It means converting
highly erodible cropland back to grassland or woodland, reducing the
livestock population, and planting tree shelter belts across the windswept
areas of cropland, as U.S. farmers did to end dust storms in the 1930s.
In addition, another interesting option now presents itself—the use of
wind turbines as windbreaks to reduce wind speed and soil erosion. With the
cost of wind-generated electricity now competitive with that generated from
fossil fuels, constructing rows of wind turbines in strategic areas to slow
the wind could greatly reduce the erosion of soil. This also affords an
opportunity to phase out the use of wood for fuel, thus lightening the
pressure on forests.
The economics are extraordinarily attractive. In the U.S. Great Plains,
under conditions similar to China's northwest, a large advanced design wind
turbine occupying a tenth of a hectare of land can produce $100,000 worth
of electricity per year. This source of rural economic regeneration fits in
nicely with China's plan to develop the impoverished northwest.
Reversing desertification will require a huge effort, but if the dust
bowl
continues to spread, it will not only undermine the economy, but it will
also trigger a massive migration eastward. The options are clear: Reduce
livestock populations to a sustainable level or face heavy livestock losses
as grassland turns to desert. Return highly erodible cropland to grassland
or lose all of the land's productive capacity as it turns to desert.
Construct windbreaks with a combination of trees and, where feasible, wind
turbines, to slow the wind or face even more soil losses and dust storms.
If China cannot quickly arrest the trends of deterioration, the growth
of
the dust bowl could acquire an irreversible momentum. What is at stake is
not just China's soil, but its future.
<end>
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sent on by David.
(David MacClement) davd@ihug.co.nz
http://www.geocities.com/davd.geo/index.html#top
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