Causes of more frequent sandstorms in China

"Between Ad 300 and 1949, northwestern China experienced a sandstorm on average every 31 years, but after 1990, the average increased to one sandstorm per year, while by 2006, the average rate of sandstorms for the Beijing region was five or six a year" (Visible earth, 2006). According to the dictionary, a sandstorm is a storm in which sand is blown into the air by strong winds (Oxford Advanced Learner's English-Chinese Dictionary). Overgrazing, overharvesting of ground flora and nonstandard mines resulting in grasslands degenerating into deserts as well as climate change accelerating the wind strength together lead to more frequent sandstorms in China.
First of all, overgrazing and overharvesting are creating more sand sources these years that directly caused more sandstorms. "Grassland Sustainable Development Research of China", which was done by Development Research Center of The State Council of China in 2003, indicated that the overgrazing was an acute environmental problem: by 2003, the average overgrazing rate of the grassland in Northern China was above 36%. In other words, when the amount of livestock in northeast China has exceeded the capability of the grassland, the growth of grass cannot catch up with the rate of abatement, which results in the descending of grassland. As a result, the soil is exposed to the air causing degeneration of soil. Moreover, some of the ground flora in northwest China is ideal herb. Liu and Diamond (2005) argued that because of overharvesting, the grass production in a unit hectare has been decreasing to about 60% since the 1950s. Taking liquorice: as an example, people are digging out liquorice blindly for tiny economic benefit, which may not only make the liquorice extinct but also break the balance of living conditions of other ground flora. Without the ground flora keeping nutrition and water in the soil, the soil degenerates into sand. So more frequently, the sand storm is created.

Furthermore, sand sources are being made by illegal or bad-planned mining. As stated by Farndon (2007), China is comparatively short of oil and gas resources. Thus, 70 percent of its energy comes from coal. A large number of coalfields are distributed over northwest China. For the sake of profits, many nonstandard and small-scale mines are set up illegally on the area that was forest or grassland before. Just like millions of the rabbet dens under the Australian ground surface, these mines in China are usually improperly developed, which leads to large segments of exposed ground and ruined plants' roots. The waste is disposed without consideration of decontamination, resulting in the degradation of soil which is, in other words, bringing about more sand storms to our lives.

In addition, the accelerator of sand storms, namely wind, is changed by overall climate change. According to Zhang et al. (2005), analyses and researches have already indicated that apart from the phenomenon of El Nino, greenhouse and the abnormality of the climate, the Northern Hemispheric Polar Vortex has changed the Asian West Wind Index (AWWI) partially. Therefore, more gusty days will appear in spring season which generate higher probability in blowing tons of sand into the atmosphere. Degenerated grassland has no power in keeping the soil from blowing away and scattered trees cannot slow down the strong wind. As a result, the change of wind power also causes more sand storms.

In conclusion, the increasing number of sand sources and the growing power of wind are the two main reasons for more sandstorms. Overgrazing, overharvesting of ground flora and nonstandard mines are the three main causes of degeneration of grassland in China and the source of more sand. At the same time, the climate change has a profound influence on changing the wind power. To reduce sandstorms, Chinese government has implemented many methods including policies to control overgrazing and overharvesting, legislation to normalize the nonstandard mines and building up the Green Great Wall. With all these methods which are directly pointing to the main causes, sandstorms can be reduced by the efforts of China.
References:

Development Research Center of the State Council . (2003). Grassland sustainable development research of China. Retrieved March 12, 2008, from www.ccag.com.cn/downloads/c_SADPII/strategy_workshop/eng/DRC.ppt

Farndon, J. (2007). China rises: How China's astonishing growth will change the world. London: Great Britain.

Hornby, A. S. (2004). Oxford Advanced Learner's English-Chinese Dictionary (6th ed.). Beijing: ShangWu Yin Shu Guan.

Liu, J., & Diamond, J. (2005). China's environment in a globalizing world. Nature, 435, 1137-1286. Retrieved March 12, 2008, from nature.com.

NASA. (2006, April 19). Dust over Japan. Retrieved March 12, 2008, from http://visibleearth.nasa.gov/view_rec.php?id=17521
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Zhang, G.F., Zhao G.P., Na, L., Hu, W.D., Sun, Y.C., Wang, W.D. (2005). Analysis on the trend and reason for spring sandstorm in Ningxia. Journal of Nanjing Institute of Meteorology, 18, 410-415. Retrieved March 16, 2008, from www.cabi.org.