This region was once a large grain-producing region on which the Roman Empire was dependent – an illustration of the fact that climate change is not solely a modern phenomenon.
The population is primarily Arab and Berber, with smaller numbers of Bedouin and other minorities. These countries serve as magnets for the mobile of the countries immediately south of the Sahara, and as routes for migrants hoping to evade detection as they enter southern Europe.
These countries are primarily poor. There has always been a wealthy elite, in Egypt and the other strategic cities of the region. But little of that wealth has touched the ordinary inhabitants.
In modern times there has been a growth of commercial agriculture in some parts, and of oil, gas or mineral extraction in others. Tourism is a major income source for Egypt, Tunisia and Morocco.
Yet life for most citizens of this region is grindingly poor, with few opportunities for improvement. Unemployment is high; health, education services, water supplies, road networks and other facilities are poor for most.
These countries all have governments with a strong sense of nationalism, where dissent of any kind is suppressed with vigour. Each one of these countries has been cited as a place of frequent human rights abuses.
Islam is heavily protected by law in each of these countries. In some, conversion to Christianity and the starting of churches is expressly illegal. Christians face continual harassment and discrimination, with the ever-present possibility of arrest or of death.
Even in Egypt, where until 10 years ago Christians were left largely to themselves, there is increasing violence. Much Christian ministry has to be done in conditions of great secrecy.
Individual Christian converts are often thrown out of their families and communities, who may also report them to the authorities.
At the same time, the governments of each of these countries fear the power of radical Islam. The position of the elite is in each case based on an institutional Islam which has a cosy relationship with those in power. The primary goal has been wealth accumulation rather than expansion.
Those who want to change this are feared. The remoteness of the desert regions gives plenty of opportunity for training camps for radicals bent on violence at home or abroad.
The future of this region will depend very much on how these challenges are faced.