For the whole history of the Roman Empire, Egypt as a major source of grain for Rome is a given. But it seems the rest of North Africa was as well. Take for example the post-tetarchy chaos when Constantine ruled in Gaul and Maxentius in Italy. The revolt of Domitius Alexander in north Africa causing major political problems for Maxentius due to the shut down of the grain supply from north africa is common knowledge. I had always assumed "North Africa" in this context included Egypt. However based on the following, it seems Domitius did not control Egypt, only what is now modern Libya and surrounds. https://en.m.wikipedia.org/wiki/Domitius_Alexander This does not jive with the modern condition of agriculture in this area. Libya does not grow enough food to handle even 25% of its national need and is relying on major aquifer irrigation projects which clearly did not exist in Roman times ( https://en.m.wikipedia.org/wiki/Economy_of_Libya )
Did climactic change or human mismanagement destroy agriculture in this region? What happened?
“Africa” in a Roman context doesn’t refer to Egypt or (most of) Libya—it refers to the Maghreb, specifically the coastal region from Carthage to the Atlantic. This region produced, and continues to produce, substantial quantities of wheat and olive oil.
