Answer:
Deforestation, and desertification. Deforestation can cause desertification, and desertification can cause droughts. To address this issue of deforestation, we could stop using urbanizing Africa, and start rebuilding its ecosystems.
Explanation:
No ecosystem can function without water, and in order to stop deforestation, we need to stop desertification, and vice versa. Deforestation <em>causes</em> desertification, because without trees, the water in the ground is easy (for the sun) to evaporate, and without water trees can't grow.