“Sandstorms” and the development of critical thinking skills 1

After completing the activities about sandstorms in the worksheets on “Weather and Climate”, you may have basic understanding about the negative impact of sandstorms and the methods used to combat them. Is this the complete story? In fact, there are pros and cons for everything. This provides a good opportunity for you to develop your critical thinking skills. This set of worksheets contains two extended activities about sandstorms which help facilitate the development of critical thinking skills.

1.Refer to Appendix 1 about the negative impact of sandstorms.Try to classify the impact into the categories listed in Table 1. Gather further information from the Internet.

Economic Aspect
Environmental Aspect
Social Aspect
Transport
Others

Table1

2.Based on the information in Table 1, do you think sandstorm is a disaster to the residents ofBeijing? Why？

3.Based on what you know, do you think sandstorms have contributions to human beings? Explain your viewpoints.

4.Refer to the information on Appendix 1 and Appendix 2, form yourselves into groups and carry out a debate based on the motion below. Search for more relevant information and record yourinformationin Table 2.

As the media usually reports the negative impact ofsandstorm only, this activity provides an opportunity for students to use multiple perspectives to analyse the contrasting views of different people, so as to reflect the interactions between sandstorms andhuman beings.

A Geography Teacher

Motion：Sandstorm is a blessing to human beings.

For / Against

Table2

5.After completing the above activities, how would you evaluate sandstorms?State and explain your viewpoints in the space provided below.


ToBeijing, the capital city of China, the effects of sandstorms on its economic development and social well-being are significant. Therefore, different strategies are adopted to combat sandstorms. Are they good methods? Study the newspaper clippings in Appendix 3 and Appendix 4, and answer the following questions.

1.Do you agree using afforestation to combat sandstorms? Why?

2.According to the newspaper clipping in Appendix 4, besides tree-planting, grass-planting is another way to combat sandstorms. Do you think planting grasses is more effective than planting trees in combating sandstorms? Explain your answers.


Appendix 1

The Negative Impact of Sandstorms

Appendix 2

Appendix 3

Afforestation is the major method used by a number of past Chinese leaders on combating sandstorms.They thought that it was a critical foundation to the prosperity of the country and people. They believed a patch of grass can withstand tons of sand！Mao Zedong announced the following mission in 1955—“To plant trees besides residence, villages, roads, water bodies, barren land and hills and all other possible areas, in order to build a green country” (在一切宅旁、村旁、路旁、水旁、荒地上、荒山上，即一切可能的地方，均要按規格種起樹來，實行綠化). Deng Xiaoping further suggested in 1991 that“Building a green nation is a blessing to all generations”(綠化祖國，造福萬代). It is really important to plant trees to combat sandstorms. Beijing has been greatly affected by sandstorms. Continuous efforts have been put on building a green city recently.

Since 1978, different projects on afforestation and increasing vegetation coveragewere implemented inChina. 300 million acres of trees have already beenplanted in 13 provinces across Northwestern,Northern and Northeastern parts ofChina. Over 10 million acres of grassland and improved pasture areplanted, and over 30 million acres of land have been afforested to combat sandstorms. The national vegetation coverage has been restored by 9%. This is one of thegreatest ecological constructions in the world today, and is named asChina’s “Green Great Wall”. In addition, over 100 million acres of desertified land were remedied, over 100 million acres of areas with soil erosion were under control and areas of farmland protected by shelterbelt reached a record high of over 300 million acres.

Another example is in Gulong, Gansu Province (the eastern end of Hexi Zoulang, facing TenggerDesert [Tenggeli Shamo] in the north). Since 1999, the county has introduced a theme on ecological development each year, such as “A tree and a patch of grass can prevent sandstorms”(一棵樹，一把草，壓住沙子防風掏), “Shrubs as the nominal protective measure, sand blocks as the supplementary one. Obstruct the sand in front and drag it back at the rear”(灌木為主，沙障為輔，沙前設障，前擋後拉) and “Save the soil by afforestation”(搶壤造林) . By the end of 2001, the whole county hadplanted about 170,000 acres of trees in three-year time, and over 400,000 acres of grass were planted to cover sand. As a result, the forest coverage of the county had increased from 6% to 7%.

Besides, an entrepreneurHe Yuan Cheng has developed a “liquefiedecological land cover “, which can consolidate sand in desert. In July 1999, Mr. He performed a demonstration in Duolun County (The desertification here is a direct cause of sandstorms affecting Beijing) by spraying liquefied ecological land cover and grass seeds on a barren, sandy hill which wasquality pasture originally. After one year, grass was fully developed and the migratory sand dunes became stagnant.

Appendix 4

When there are desertification and sandstorms, people usually mention“tree-planting” as a measure to combat them. However, is it effective to combat desertification and sandstorms with tree-planting？

Are trees“water pumps”？

Due to water shortage, trees are rare in arid and semi-arid areas. Herbs are the main vegetation type in these areas. In view of serious desertification in these areas, tree-planting is thus proposed to combat desertification and sandstorms. Unfortunately, the rate of water absorption of trees is much higher than that of herbs. Massive planting of trees is against the ecological environments of arid and semi-arid areas. Trees can hardly survive and a large sum of money and labour may be wasted. In fact, many trees planted in arid and semi-arid areas（e.g. Inner Mongolia）die because of their incompatibility with the geographical and ecological environment there. Even if some of them survive, they absorb a large amount of water which only intensify the droughtcondition in arid and semi-arid areas.

Can trees act as barriers to sandstorms？

Some experts pointed out that planting trees for combating sandstorms was not as effective as imagined.Sandstorms can still be found in the forests and the visibility outside the forests is extremely low. On the contrary, the visibility is relatively high on land covered with grass. The ability of trees in consolidating soil is also not as effective as herbs and shrubs, and herb layer can hardly be formed in afforested areas. So, it is doubtful whether tree-planting is effective in preventing desertification and combating sandstorms.

Reference

1.《中國國家地理》，第二十五期，二零零三年六月號。