Causes of Desertifiication
- Desertification is caused by both natural factors and human activities
- It can be argued that many of the natural causes may be made worse by human activity and climate change
Comparison Between Natural and Human Causes
Natural causes | Human causes |
Soil erosion leads to the loss of nutrients. Plants are unable to establish and grow |
Overgrazing means the vegetation has all gone due to the numbers of animals or the land does not have chance to recover |
Rainfall patterns have become less predictable leading to drought and any vegetation dying due to lack of water |
Over-cultivation leads to all the nutrients being taken up by crops leaving none for future vegetation to grow |
Reduced vegetation means that nutrients are not added to the soil through the decomposition of dead organic matter |
Deforestation removes shade for the soil and means there are no roots which bind the soil together. This increases soil erosion, whilst decreasing infiltration and interception |
Any rain that does fall is often in short, intense bursts, leading to increased surface run off and soil erosion |
Population growth puts increased pressure on the land as people raise more animals and grow more crops |
Causes of desertification
- In areas such as Kenya, both human and natural factors lead to desertification
- Grazing patterns and traditional lifestyles mean that:
- Nomadic Masai farmers have been forced to use smaller and smaller areas of land for grazing
- This results in overgrazing, which removes the vegetation
- The soil no longer has protection from the wind and rain which leads to soil erosion and desertification
- Nomadic Masai farmers have been forced to use smaller and smaller areas of land for grazing
- Population growth increases the demand for food and fuelwood
- This leads to over-cultivation and deforestation
- Deforestation:
- Reduces the amount of nutrients returned to the soil
- Exposes the soil to wind and rain
- This further increases soil erosion, leading to desertification
- In Kenya increasing temperatures and more irregular rainfall are natural causes of desertification
- However, these could be the result of the enhanced greenhouse effect (human cause) leading to climate change