It is in fact still a matter of active debate as to whether or not the Sahara is natural. Some evidence suggests humans may have played a role in its expansion

It is in fact still a matter of active debate as to whether or not the Sahara is natural. Some evidence suggests humans may have played a role in its expansion to current size, at least: https://www.sciencedaily.com/releases/2017/03/170314111320.htm https://www.sciencedaily.com/releases/2017/03/170314111320.h...