Desertification and sandstorms –
Specific examples
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I.
Purpose of using these specific examples in this module
These specific examples are chosen to broaden students’ global perspective and enable them to
have a better understanding of what is happening in other parts of the world.
II. Curriculum tailoring for students of different abilities
1. Teachers should provide all students with a brief introduction of the global pattern of
desertification, major regions affected by sandstorms and the measures taken by them to
alleviate the problems.
2. For more able students, teachers can further extend the lesson to include more in-depth case
studies of how the spreading of desert dust and sand affects the inhabitants of Australia
(especially dwellers of large cities, like Sydney and Brisbane) and the Sahara. They can also
study the similarities and differences on how less developed countries and more developed
countries manage their sand problems.
III. How to make use of the information provided in this folder?
1.
2.
3.
4.
As stated in the Curriculum Guide, the two specific examples chosen are Australia and the
Sahara. Sahel is chosen in this information folder as an illustration of how desertification has
affected the area around the Sahara.
Under each specific example, there is a brief introduction of the desertification problem and
their causes. The solutions adopted to solve this problem will also be introduced.
Teachers need not cover all the information provided in this folder. Instead it is advisable for
them to select appropriate example(s) and refine the materials based on the ability and interest
of their students.
Teachers can make use of the materials as:

Background information for students to understand the causes of desertification and
sandstorm and how the problem is being tackled;

Information for comparing the solutions adopted in Australia and the Sahel;

Materials for self-study.
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I. Definition of desertification
The United Nations Convention to Combat Desertification (UNCCD) defines the term
as:
“land degradation in arid, semi-arid and sub-humid areas resulting from various factors
including climatic variations and human activities.”
II. Global desertification problem
In 2012, about 1/3 of the Earth’s surface is threatened by desertification. It has been
estimated that global desertification has put the livelihood of 1000 million people at risk
and eventually about 135 million people may be forced to leave their land. This problem
is especially serious in the Sub-Sahara regions.
Desertification map of Africa
http://www.unep.org/geo/geo3/english/fig71.htm
Desertification map of Asia and the Pacific Region
http://www.unep.org/geo/geo3/english/fig75.htm
References:
1. Learning to combat desertification
http://unesdoc.unesco.org/images/0012/001258/125816e.pdf
2. World Day to Combat Desertification and Drought
http://www.earthtimes.org/politics/world-day-combat-desertification/2040/
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I.
Definition of sandstorm
Sandstorm is a kind of climatic hazard. It occurs when strong wind raises and carries along
clouds of sand or dust which is so dense that it obscures the sun and reduces visibility to less than 1
km. Sandstorm usually occurs in deserts, arid and semi-arid regions, such as, Sahara Desert in
North Africa, Central Australia, Southwest of USA, Central Asia and Northwest China.
II. Sandstorms of different magnitudes
Criteria for classifying sandstorms in China according to magnitude
Magnitude
Maximum peak gust
Visibility (m)
(m/s)
Very strong
≥25
<50
Strong
≥20
<200
Medium
≥17
200-500
Weak
≥10
500-1000
Figure 1: Sources of sandstorm in East Asia (Source: Hong Kong Observatory)
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References:
1. 沙塵暴資料庫
http://www.atmos.pccu.edu.tw/duststorm.index1.htm
2. Photos showing desertification in China
http://www.chinadialogue.net/article/show/single/en/3114
http://www.environmentalgraffiti.com/featured/sandstorms-on-earth/2353?image=3
3. Satellite images of sandstorms can be seen in the following website:
http://earthobservatory.nasa.gov/Search/index.php?q=duststorm
http://www.sciencenewsline.com/summary/2012032017460010.html
4. Video showing the causes, effects and remedial measures of sandstorm
http://www.welovehk.org/welovehk/channel_content.jsp?id=261
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I.
Desertification in Australia
Australia is the world’s driest continent. There is a large piece of land with annual rainfall
varies from 250 – 800 mm, which is called the arid and semi-arid areas. The soil in these two areas
also suffers from salinization due to the arid climate. However, agriculture is Australia’s most
extensive form of land use, occupying 60% of the total land area. Livestock grazing makes up 88%
of agricultural land use. As the environmental condition in Australia is not very favourable for
agriculture, improper management in farming may lead to land degradation, which may be
intensified into desertification, leading to sandstorm as a result.
The main causes of desertification include over-grazing, removal of vegetation cover, woody
weed invasion and improper farming management. These activities may result in soil erosion, soil
degradation, increased soil salinity and loss of biodiversity.
New South Wales and Queensland was hit by the worst
dust storm (sandstorm)
Between 22 and 24 September 2009, a strong sandstorm swept across
the Australian states of New South Wales and Queensland. On 23 September,
the dust plume was more than 500 km in width and 1000 km in length and
covered many cities and towns in these two states. Sydney, for example, was
covered by reddish-orange cloud, with visibility reducing to between 100-200
m. The air quality index for New South Wales was 4164 in Sydney. (The
level above 200 is considered as hazardous.) Up to 75,000 tonnes of dust per
hour was blown across Sydney and dumped into the Pacific Ocean. On 25
September, the dust reached New Zealand which is 2,200 km away.
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The storm affected the livelihood of the people in the New South Wales
and Queensland. People suffering from asthma, heart or lung diseases were
advised not to go out. Traffic, especially air flight was disturbed. This
sandstorm was caused by severe drought. Rainfall in the eastern interior of
Australia decreased resulted in drought in the autumn in 2009. Temperature
was abnormally high, which was the second-hottest year on record.
Therefore, drought problem became more serious leading to less vegetation
cover. Together with the strong wind in those months (up to an average of 65
km / hr), wind erosion became serious which blew the sand from the interior
part of Australia which is the desert area, to the eastern part of Australia.
The following website shows the animation of how the dust was spread to different parts of
Australia from 23 – 26th September 2009:
http://www.csiro.au/en/Outcomes/Environment/Australian-Landscapes/Dust-storm-animations.aspx
The following websites show the photographs of Sydney under this severe sandstorm:
http://abyteofenews.wordpress.com/2009/09/23/sand-storm-in-sydney-australia-incredible-images/
http://cloudfanatic.blogspot.hk/2009/09/sand-storm-over-sydney-23rd-september.html
II. What have the government done to combat desertification and sandstorm?
The main cause of desertification and sandstorm is land degradation. Therefore, the Australian
government has adopted different measures to alleviate the problem of land degradation.
A. Legislation and strategies


Environmental management is coordinated by the federal, state and local governments.
Different governmental level is responsible for the holistic to localized policy in
managing the environment.
The National Strategy for Rangelands Management identifies the actions needed to
protect and enhance the natural resources which can prevent land degradation. The
conditions of these grazing lands are carefully monitored through best practice grazing
management and control of number of animals reared.
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B. Research and monitoring


The Federal and State Governments have organized many research and monitoring
works examining the effects and developing innovative approaches to reducing the
impacts of land degradation. These researches mainly focused on improving
productivity and environmental management in the grazing industry.
Voluntary organizations and research teams have also conducted researches on
developing land in a sustainable way. Since the grazing lands are ecologically sensitive,
researches have been done to evaluate the effects under different scenarios, such as
climate change or drought. Recommendations on the capacity of land and the planning
of development after considering the interest of different stakeholders are given.
C. Collaboration with local community, especially the indigenous people
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

Indigenous people manage about 18% of the total land area. So their contribution to the
conservation of land use is important.
The Federal government has established a national network of 13 Indigenous Land
Management Facilitators. The role of these facilitators is to:
 Act as a link between Indigenous land managers and other individuals and
organizations involved in promoting sustainable land management and biodiversity
conservation;
 Ensure that the indigenous communities within a region are aware of the land
management issues and initiatives in their region;
 Provide information about the types of support and technical advice that is
available to assist them with land management.
Funding is also provided to help indigenous people to improve fire management, to
introduce reforestation in semi-arid communities and to plant suitable vegetation species
as native bush food sources.
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D. Actions done at local level

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Strategic tree planting has been done to prevent soil salinization. Saltbush is used because
they can absorb soil moisture, keeping down the groundwater level.
Trees can prevent soil erosion which in turn can minimize the occurrence of sandstorm.
Reforestation, using native species where appropriate, has been carried out to regenerate
degraded forest.
Soil conditions are monitored throughout the country so that soil erosion can be
controlled.
The effectiveness of different land use management and vegetation cover on soil is
intensively monitored to avoid the worsening of soil erosion.
E. Education



Many educational activities have been organized to raise the awareness of the general
public on the problems of drought and desertification.
Educational case studies have been conducted and forums and discussions on drought and
desertification and its implications on the world have been organized by world
organizations, such as the United Nations Convention to Combat Desertification
(UNCCD), to consider ways on how these problems can be minimized.
Since 1994, the United Nations (UN) General Assembly has declared June 17 as the
World Day to Combat Desertification and Drought. It aims at arousing the international
awareness over this issue and urges governments to take action.
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References:
1. Australian actions to combat desertification and land degradation
http://www.environment.gov.au/land/publications/actions/domestic1.html
2. Australia hit by worst dust storms in 70 years
http://www.cbc.ca/news/world/story/2009/09/22/australia-sydney-dust-storm-outback.html
3. Desertification – a Global issue
http://www.nynrm.sa.gov.au/Portals/7/pdf/biodiversity/global.pdf
4. Desertification vulnerability: Asia and the Pacific
http://www.unep.org/Geo/geo3/english/154.htm
5. Drought and severe dust storm in Sydney, Australia
http://www.climatehotmap.org/global-warming-locations/sydney-australia.html
6. Dust storm chokes Sydney
http://www.abc.net.au/2009-09-23/dust-storm-chokes-sydney/1438510
7. Implementing the proposals for Action of the Intergovernmental Panel on Forests and the
Intergovernmental Forum on Forests
http://www.daff.gov.au/__data/assets/pdf_file/0006/37590/summary_of_pfa_aust_wb_profor.
pdf
8. Monitoring soil condition across Australia. Recommendations from the Expert Panels
https://www.asris.csiro.au/downloads/Monitoring%20Soil%20Condition%20ver_4.doc
9. Sustainability in Australia’s arid lands
http://www.csiro.au/Outcomes/Water/Rural-and-regional-water/arid-land-sustainability.apsx
10. Visible from space: The wall of dust marching across the Australian outback to turn the skies
over Sydney blood red
http://www.dailymail.co.uk/news/article-1215443/Australia-dust-storm-sweps-eastern-coast.
html
11. World Day to Combat Desertification and Drought
http://www.earthtimes.org/politics/world-day-combat-desertification/2040/
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I.
Desertification in Sahel
Sahel is situated in North Africa along the southern edge of the Sahara Desert. Its coverage
includes Senegal, southern Mauritania, central Mali, southern Algeria, southern Niger, central Chad,
southern Sudan, northern South Sudan and Eritrea. The climatic type of the region is tropical
semi-arid with low annual rainfall of about 600 mm. In 2012, there are about 309 million people
living in this region and the population is growing at a rate of 3% per year. About 70% of the
region’s population live in rural area and rely on farming. Some are nomadic cattle herders but most
are subsistence farmers growing sorghum, cotton and millet. They are among the poorest and most
vulnerable to climatic variability and desertification.
The problem of desertification is becoming more serious because more droughts occurred in
recent years. The effects of such climatic anomalies are further worsened by human activities. As
population in the Sahel grows at an increasing rate, more and more people practice sedentary
farming instead of nomadic pastoralism to gain their living, resulting in serious overgrazing and
over-cultivation in the region. As there is no time for the land to replenish their fertility, when
drought came, the land will be subjected to soil erosion. In addition, people living in the Sahel have
over-exploited the trees as fuelwood or construction poles. Deforestation has removed the
protection of the soil and they are subjected to soil erosion. Soil becomes loose and sandstorm is
common in the area. The most serious effect of desertification and sandstorms is crop failure.
Productivity of land drops and people may suffer from famine if this condition persists. By January
2012, more than 10 million people in Sahel are at risk of food shortages. Ten million families will
have exhausted their food reserves.
References:
1. Climate change, desertification and migration: Connecting the dots
http://www.rtcc.org/climate-change-desertification-and-migration-connecting-the-dots
2. Combating desertification – what makes the desert beautiful is that somewhere it hides a well
http://www.developmenteducation.ie/media/documents/Desertification.pdf
3. Desertification – a threat to the Sahel
http://www.eden-foundation.org/project/desertif.html
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4. Desertification in the Sahel
http://oceanworld.tamu.edu/resources/oceanography-book/desertificationinsahel.html
5. Why is the Sahel shifting?
http://science.howstuffworks.com/environmental/green-science/sahel-shifting1.htm
II.
What have been done to combat desertification and sandstorm in Sahel?
A. Great Green Wall Initiative
In 2007, African Heads of State and Government have endorsed the Great Green Wall
Initiative which targeted to combat desertification and sandstorm in the Sahel region. It has
been planned that a tree belt of about 8000 km long and 15 km wide will be planted along the
southern border of the Sahara Desert covering more than 20 countries. The project is
financially supported by the Food and Agriculture Organization of the United Nations
(UNFAO), the United Nations Environment Programme (UNEP), the United Nations
Convention to Combat Desertification (UNCCD), the European Union and the African Union
Commission. Drought-adapted species which are native to the region will be planted. The
project not only contains the planting of trees but also includes:

Biodiversity conservation



Sustainable management of natural resources, including soils, water, forests, grazing
lands
Promotion of sustainable rural production systems in agriculture, pastoralism and
forestry
Diversification of economic activities, e.g. through rural production centers, to
stimulate job creation and offer income generation activities, in particular for youth
and women
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Planting of vegetation helps the formation of rain through the evapotranspiration process
facilitated by green plants. Trees could also help to minimize wind intensity, slowing down
wind erosion and reducing the spread of sand. The whole project not only can conserve the
natural environment but are also a kind of sustainable development. Once the economic and
social conditions of the native people improve, they can make a better use of the land and the
actions to conserve the nature can be more effective.
B. Development of Agroforestry
In order to control desertification and to solve the problem of food shortage, some
countries in the Sahel began to develop agroforestry. A few selected trees or shrubs are
grown in a scattered pattern on cultivated land together with crops or on grazing land where
animals are reared. Many African countries found that agroforestry together with water
harvesting1 is a more efficient method in raising agricultural productivity than large-scale
irrigation system which requires huge investment, and creates severe and negative
environmental and social impacts. This solution has several advantages:

It is very effective in increasing soil fertility because trees drop organic matter onto
the soil and release nutrients.

Tree roots can hold the soil together, preventing wind erosion.

Trees can protect the crops by filtering the sunlight and thus lowering soil
temperature. When the trees are too tall or dense to shade most of the sunlight, they


will be cut as fuelwood or timber.
Trees’ leaves and pods can be used as fodder crops (feed for livestock). This can be
an important food source for livestock during the dry season.
Tree products such as timber, resins and fruits can supplement the income of
farmers in case of crop failure.
1
Water harvesting means capturing rain where it falls or capturing the runoff in your own village or
town. Refer to the following website for further details:
http://www.rainwaterharvesting.org/whatiswh.htm
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It has been estimated that there will be an average of 116% increases in average food
yield in Africa in 2011. This practice has becoming more and more popular in the Sahel.
C. Other measures
1.
Rainwater use efficiency
Rain in Sahel usually falls in high intensity causing rapid surface runoff which erodes
the soil and in turn leads to soil moisture deficit. Rainwater loss to runoff accounts for
20-40% of annual total rainfall in the Sahel making the largest contributor to lack of
moisture. Therefore, shrubs are grown in rows (called hedgerow systems) and stone are
placed on slopes in rows to limit runoff in fields because they provide a barrier to runoff. In
Kenya, hedgerow systems are used which increase infiltration and help to increase
agricultural yield. They also help to combat desertification as soil moisture increases.
2.
Better farming practices and population control
Overgrazing and over-cultivation are the major causes of desertification and sandstorm
in the Sahel region. Therefore, the number and intensity of crops grown and animals reared
must be controlled. Farming methods that help to conserve soil fertility and moisture must
be adopted. This can be done through providing education to the farmers. However, the
hidden reason for overgrazing and over-cultivation is population growth. So population
control is another solution for the problem. Government or non-government organizations
must help to educate local people on the importance of birth control and the ways of
contraception.
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References:
1. Anonymous (2010). Africa’s “Great Wall” aims to slow desertification. Bulletin of the American
Meteorological Society, 91.9 Sep 2010:1167.
2. Anonymous (2012). The Great Wall of Africa. Utne, 170 Mar/Apr 2012:23.
3. Leathy Stephen (2011). Food production: Green Sahel provided lessons in halting
desertification. Global Information Network, 17 October 2011.
4. Madeley, John (1999). Senegal fights back against desertification of its land. Financial Times,
16 Feb 1999: 28.
5. Africa’s “Great Green Wall” bears fruit for families in Sahel
http://www.wfp.org/stories/africas-great-green-wall-bears-fruit-village-senegal
6. African nations strive to stem desertification with a ‘Great Green Wall’
http://www.un.org/apps/news/story.asp?NewsID=44671
7. Agroforestry: a route to food security in the Sahel
http://www.treeaid.org.uk/2013/agroforestry-a-route-to-food-security-in-the-sahel
8. Agroforestry is regreening the Sahel
http://civfi.com/2011/12/19/agroforestry-is-regreening-the-sahel
9. Climate change and variability in the Sahel Region: Impacts and adaptation strategies in the
agricultural sector
http://www.unep.org/Themes/Freshwater/Documents/pdf/ClimateChangeSahelCombine.pdf
10. Great Green Wall
http://www.fao.org/partnerships/great-green-wall/great-green-wall-home/en/
11. Great Green Wall for the Sahara and the Sahel initiative
http://www.fao.org/docrep/016/ap603e/ap603e.pdf
12. Impact of desertification – Desertification and the Sahel
https://sites.google.com/site/desertificatioandthesahel/impact-of-desertification
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13. Is the Great Green Wall the end of the line for desertification?
http://www.earthtimes.org/climate/great-green-wall-the-end-of-the-line-for-desertification/398
14. Sahel region learning to reap the benefits of shade
http://www.ipsnews.net/2013/02/sahel-region-learning-to-reap-the-benefits-of-shade
15. The Great Green Wall Initiative
http://www.thegef.org/gef/great-green-wall
16. The Great Green Wall of Africa
http://www.atlasobscura.com/places/the-great-green-wall-of-africa
17. UNEP support to the Great Green Wall for the Sahara and the Sahel Initiative
http://www.unep-wcmc.org/unep-support-to-the-great-green-wall-for-the-sahara-and-the-sahelinitiative_862.html
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