1. Overpopulation Impact on Resources

8. Effects of Overpopulation on Resources Overpopulation can lead to the overuse and degradation of resources Overpopulation can lead to the overuse and degradation of resources Where? Where? Sahel, Africa. Sahel, Africa. (Includes parts of Sudan)

9. Causes of Desertification Human activities; overgrazing, deforestation (triggered by overpopulation) Human activities; overgrazing, deforestation (triggered by overpopulation) Climate change; drought Climate change; drought

10. Areas affected by Desertification

12. Overgrazing Cattle are a sign of status Cattle are a sign of status More people mean more cattle More people mean more cattle Nomads graze more cattle on the land than it can support Nomads graze more cattle on the land than it can support Reduces plant cover Reduces plant cover Grasses often do not re-grow Grasses often do not re-grow Soil damaged Soil damaged Infertile, unsuitable for crops Infertile, unsuitable for crops

14. Deforestation Trees removed for fuel. Trees removed for fuel. Trees removed to clear land for crops. Trees removed to clear land for crops. Less tress mean reduced transpiration of moisture from them. Less tress mean reduced transpiration of moisture from them. As a result the atmosphere contains less moisture and there is less rainfall in the region. As a result the atmosphere contains less moisture and there is less rainfall in the region.

16. Deforestation; Fuel Increase in population Increase in population High demand for fuel High demand for fuel Forest clearances Forest clearances Soil exposed to wind and flash floods Soil exposed to wind and flash floods Soil erosion Soil erosion Animal manure may be used as fuel, thus depriving the soil of fertiliser. Animal manure may be used as fuel, thus depriving the soil of fertiliser.

17. Over-cropping/Over- cultivation Pressure to grow cash crops Pressure to grow cash crops Cotton, beans, etc Cotton, beans, etc Plantation workers get small tracts of land beside plantations Plantation workers get small tracts of land beside plantations To feed their families they grow crops here continuously To feed their families they grow crops here continuously Land cannot be left fallow Land cannot be left fallow Soil loses its nutrients and becomes useless Soil loses its nutrients and becomes useless Desertification Desertification

20. Climate change 30% decrease in rainfall levels in the Sahel in 20 years. 30% decrease in rainfall levels in the Sahel in 20 years. Drought more frequent Drought more frequent Dry soil leads to soil erosion Dry soil leads to soil erosion Wells have been dug anywhere possible Wells have been dug anywhere possible This dries out the soil even more This dries out the soil even more