Scientists are predicting that water and life may slowly reclaim the world's most torturous deserts despite prediction of doom from some quarters.
According to a report by BBC News, the evidence is limited and definitive conclusions are impossible to reach, but recent satellite pictures of North Africa seem to show areas of the Sahara in retreat.
It could be that an increase in rainfall has caused this effect.
"It's not greening yet. But the desert expands and shrinks in relation to the amount of energy that is received by the Earth from the Sun, and this over many thousands of years," el-Baz told the BBC World Service.
"The heating of the Earth would result in more evaporation of the oceans, in turn resulting in more rainfall," he said.
Droughts over the preceding decades have had the effect of driving nomadic people and rural farmers into the towns and cities.
Such movement of people suggests weather patterns are becoming dryer and harsher.
The Intergovernmental Panel on Climate Change warned recently that rising global temperatures could cut West African agricultural production by up to 50 percent by the year 2020.
But, satellite images from the last 15 years do seem to show a recovery of vegetation in the Southern Sahara, although the Sahel Belt, the semi-arid tropical savannah to the south of the desert, remains fragile.
The fragility of the Sahel may have been exacerbated by the cutting of trees, poor land management and subsequent erosion of soil.
The broader picture is reinforced by studies carried out in the Namib Desert in Namibia. or the last few years, there has been higher than average rainfall in the area.
This is a region with an average rainfall of just 12 millimetres per year - what scientists call "hyper-arid".
Last year, the local research centre, called Gobabeb, measured 80mm of rain.
In the last decade, they have seen the local river, a dry bed for most of the year, experience record-high floods. All this has coincided with record-high temperatures.
According to Mary Seely, a scientist from Gobabeb, "Deserts and arid areas always have extremely varied rainfall. You would have to look at a record of several hundred years to maybe say that things are getting greener or dryer. For the last few years, there has been higher than average rainfall."