The process of desertification

Transcription

1 Desertification in the Sahel. The location of the Sahel. The causes of desertification in the Sahel. Drought: The Sahel region of Africa has been suffering from drought on a regular basis since the early 1980s. The area naturally experiences alternating wet and dry seasons. If the rains fail it can cause drought. It is thought that climate change might be causing a disruption to the rainfall patterns. Marginal land: In addition to natural factors, the land is marginal. Overgrazing: The farmers of the Sahel greatly value their livestock and sometimes the cattle numbers are too big for the amount of grass available, so the grass is overgrazed leaving lots of bare ground. Over-cultivation: With rising human populations there is pressure on the land to grow food. Over-cultivation often leads to the soil becoming exhausted and losing fertility. Crops die off and the land is left bare. Collection of firewood: The collection of firewood for heat and cooking reduces the forest cover (due to deforestation), leaving the land bare and less sheltered against the wind. Soil erosion: Bare soil can be eroded by the action of wind and rain and the topsoil is lost. Dry bare soil will be blown away by the wind and soil may also be washed away when it rains Page 1 of 9

2 The results of desertification in the Sahel. The results of desertification are famine and hunger, and people are then less able to work when their need is greatest. It becomes a vicious circle and can result in many deaths, especially among infants and the elderly. In Niger in 2004, there was hardly any rain during the wet season and the situation was made worse when a plague of locusts consumed any remaining crops. In these cases, people rely on food aid from the international community. On its own, food aid is unsustainable in the long term. What is really needed is development aid, which involves educating the local community in sustainable farming practices. The poor countries of the Sahel region rely upon farming for about 40% of their GDP. Therefore, desertification can have a terrible effect upon their economies. Desertification is also a cause of some of the large-scale international migration we are currently seeing as people migrate from North Africa to Europe. Key words: Climate change: The change in global climates observed from the mid-20 th century onwards. Caused by the rise in concentrations of atmospheric carbon dioxide produced by the use of fossil fuels (a better term to use than global warming). Development aid: This is financial aid given to a country by other countries to support economic, environmental, social and political development. Food aid: Basic food supplies, given to a country when the country is experiencing food shortages. GDP: This stands for Gross Domestic Product and it is a measure of the wealth of a country. International migration: The permanent movement of people from one country to another. Marginal land: Land that is very poor and only just suitable for farming. Topsoil: The upper fertile layer of soil Page 2 of 9

3 Cards for flow diagram activity: Population increase Climate change Land becomes infertile and turns into desert More fuel and grazing land needed Less rain Trees are cut down Soil eroded by the wind Less grass cover Soil becomes bare Population increase Climate change Land becomes infertile and turns into desert More fuel and grazing land needed Less rain Trees are cut down Soil eroded by the wind Less grass cover Soil becomes bare Population increase Climate change Land becomes infertile and turns into desert More fuel and grazing land needed Less rain Trees are cut down Soil eroded by the wind Less grass cover Soil becomes bare Page 3 of 9

4 The process of desertification Place the labels in the correct boxes. Population increase More fuel and grazing land is needed Climate change Trees are cut down Less rain Soil eroded by wind Less grass cover Land becomes infertile and turns into desert Soil becomes bare Page 4 of 9

5 The process of desertification Fill in the missing words. Population Climate Infertile Soil Grass Fuel Trees Grazing Eroded Desert Rain increase More and land is needed Less cover are cut down change Less becomes bare Soil by wind Land becomes and turns into Page 5 of 9

6 Causes of desertification question: Writing frame. Use the prompts to help you to structure you answers. First of all underline the command words and the key phrases in each question. Fill in the spaces with your own writing. Refer to your flow chart and the information sheet about desertification in the Sahel. Explain the causes of desertification in a region you have studied. (6 marks) Region studied:... The main causes of desertification are... The main human cause of desertification in the... region is The main natural cause of desertification in this region is... These two causes create a chain of events that lead to desertification by Page 6 of 9

7 Impacts of desertification question: Writing frame. Use the prompts to help you to structure you answers. First of all underline the command words and the key phrases in each question. Fill in the spaces with your own writing. Refer to your flow chart and the information sheet about desertification in the Sahel. Explain how desertification can have impacts upon the economy and society of a region you have studied. (6 marks) Region studied:... Desertification in the... region of Africa has had impacts upon the the economy (the wealth) of the region. These impacts include... Desertification has also had impacts upon the society (the people s lives) within the region. These impacts include Page 7 of 9

8 General marking criteria for 6 mark questions (adapted from AQA, OCR and Edexcel GCSE specifications) Level 1: Basic (1-2 marks) Knowledge of basic information. Simple understanding. Little organisation; few links; little or no detail; uses a limited range of specialist terms. Reasonable accuracy in the use of spelling, punctuation and grammar. Text is legible. Level 2: Clear (2-4 marks) Knowledge of accurate and relevant information. Clear understanding. Organised answers, with some linkages; occasional detail/examples; uses a good range of specialist terms where appropriate. Considerable accuracy in spelling, punctuation and grammar. Text is legible. Level 3: Detailed (5-6 marks) Knowledge of detailed accurate and relevant information. Detailed understanding, supported by relevant evidence and examples. Well organised, demonstrating detailed links between ideas. Clear and fluent expression of ideas in a logical form; uses a wide range of specialist terms where appropriate. Accurate use of spelling, punctuation and grammar. Text is legible. What mark did you give and why? Page 8 of 9

9 Teacher notes The introductory videos look generally at what desertification is and also the causes and impacts of it. The pupils should watch and aim to list some causes and impacts of desertification. No real detail is required as this is just to give them an overview of the issue. With reference to the Sahel desertification sheet, the class should complete the flow diagram exercise (differentiated). They can either come up with their own flow diagram or chain using the cards provided, or use one of the differentiated worksheets for support. Show the answer slide (slide 4) at the end to ensure the class understands how the different aspects influence each other. There are two practice examination questions with writing-frames (if needed) for students to complete so that their understanding can be assessed. They should highlight the command and key words within the question first: Explain the causes of desertification in a region you have studied. (6 marks) Explain how desertification can have impacts upon the economy and society of a region you have studied. (6 marks) Pupils could peer-assess their answers using the mark scheme provided. Could be printed off, to allow them to use it as a mark scheme. Munion [GFDL ( or CC BY-SA 3.0 ( via Wikimedia Commons, commons.wikimedia.org/wiki/file%3amap_of_the_sahel.png Page 9 of 9