Causes of Desertification & Deforestation (Edexcel IGCSE Geography)
Revision Note
Causes of desertification
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 deforestation
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
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
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
Examiner Tips and Tricks
It is important to remember that the causes of both desertification and deforestation are often a combination of factors rather than any one cause.
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