Causes of Desertification & Deforestation (Edexcel IGCSE Geography)

Causes of Desertification

Spec point — 4GE1-S3.064

• Desertification is caused by both natural factors and human activities
• Many of the natural causes may be made worse by climate change

Natural causes

• Soil erosion leads to the loss of nutrients. Plants are unable to establish and grow
• Rainfall patterns have become less predictable leading to drought and any vegetation dying due to lack of water
• Reduced vegetation means that nutrients are not added to the soil through the decomposition of dead organic matter
• Any rain that does fall is often in short, intense bursts, leading to increased surface runoff and soil erosion

Human causes

• Overgrazing means the vegetation has all gone due to the number of animals or the land does not have a chance to recover
• Over-cultivation leads to all the nutrients in the soil being used
• Deforestation removes shade from the soil which means there are no roots which bind the soil together. This increases soil erosion, whilst decreasing infiltration and interception
• Population growth puts increased pressure on the land as people raise more animals and grow more crops

Causes of Desertification

Causes of Deforestation

Spec point — 4GE1-S3.064

• Deforestation is the felling and clearance of trees
• Brazil, Democratic Republic of the Congo and Indonesia are experiencing the highest levels of deforestation in the world

World Deforestation 2015

Natural causes of deforestation

• Wildfires are a natural cause of deforestation

  • The frequency and severity of wildfires have increased. This is linked to climate change

Human causes of deforestation

• There are six main human causes of deforestation

Human Causes of Deforestation

Worked Example **(i) Define the term deforestation **

(ii) Outline two causes of deforestation

(6 Marks)

• Answer:

• (i)

  • The maximum mark requires a full and accurate definition
  • The felling** (1) **and removal/clearance of trees (1)

• (ii)

• Any two of the following to gain 1 mark to each for the cause with the 2nd mark for outlining/expanding linked to 1st mark so that cause is clear

  • Hydropower (1) to make space for dams and reservoirs (1)
  • Mining** (1)** to make space for mining equipment and buildings (1)
  • Agriculture (1) for grazing or planting crops (1)
  • Settlement (1) to make space to build houses (1)
  • Timber (1) for furniture/building/paper (1)
  • Roads (1) to gain access to transport resources and people (1)

• Factors need to be specific, not just human activity or climate

Exam Hint It is important to remember that the causes of both desertification and deforestation are often a combination of factors rather than any one cause.