Desertification Desertification happens in The Sahel region of Africa. The main physical cause of desertification is a decrease in the annual rainfall so reducing the water available to maintain the vegetation leading to grassland changing to desert. Also rainfall can be unpredictable and sometimes heavy so leading to soil erosion and the removal of nutrients from the soil. Human causes of desertification include burning trees and shrubs so land is clear for farming and urbanisation (the building of towns and cities). Consequently there is less vegetation and therefore fewer roots to bind the soil together to reduce gulley erosion. Trees are cut down for firewood so reducing shade and heating the soil so moisture is rapidly lost making it hard for vegetation and crops to grow The effects of desertification include in 2004 the subsistence farmers of Mali and Niger were hit by a severe drought and a plague of locusts that almost destroyed their crops. By 2005 it was clear that 3.3 million people (including 800,000 children) were at risk from a serious food shortage. The livestock farmers were losing their cattle to starvation because the dry pastures were turning into deserts.