Even in a best-case scenario we'll have to sacrifice substantial areas of land to build dense, sustainable cities. Most of the wildlife and wilderness in that part of West Africa is already gone, most land is deforested and densely populated farmland with some protected areas here and there. The west African mangroves are mostly gone already, for example.

Hopefully Africa does a better job preserving some areas of land for animals while developing others than the West did. Some countries like Tanzania and Namibia are doing OK, others like Nigeria are environmental disasters already with a population density which can only increase.