Desertification is the process by which land becomes drier and degraded, turning once fertile land into desert. Physical causes of desertification Climate change is making temperatures hotter and rainfall less reliable and more variable, which can cause desertification.
Human causes of desertification As population increases:
more animals are kept, such as goats, which eat more vegetation (this is known as overgrazing);
people farm the land more, which removes nutrients and removes the natural vegetation (this is known as over-cultivation);
people collect and remove more fuel wood to keep warm at night or for cooking.
All of these things reduce the amount of natural vegetation (plants and trees). There are no plants or leaves to intercept rain and soil is left exposed to hot sun, so the sun bakes the soil and it cracks. When it rains, the rainwater runs over the surface of the soil rather than soaking in, which means that soil can often be washed away (soil erosion).