What is the cause of increasing desertification in Africa? What is causing the Sahara to increase in size

The human activities, mostly in the agriculture, are the most responsible for the increasing desertification in Africa.

Explanation:

The population in Africa is mostly poor, and because of that often it is uneducated and not informed properly. When it comes to agriculture this turns out to have devastating effect because the methods used are still primitive and highly damaging to the environment.

The slash and burn method is highly used. It is a method that basically destroys all vegetation so that space is opened up for agriculture, but that is often done on places where the soil is either of not good quality, or very fragile when left without its natural cover. The cleared area only serves the people for few years before it is not good for agriculture, so the process constantly continues, with the end result being destroyed land left behind. On top of this, the water from the rivers is used irrationally, so the environment gets lower amounts of water.

This cases drying out of the areas where the people practice this. Becoming more dry and combined with totally destroyed soil creates good conditions for formation or extension of a preexisting desert. In the case of Africa it is the Sahara Desert that expands because of this, gradually moving southwards.