It has been assumed that global warming would cause an expansion of the world’s deserts, but now some scientists are predicting a contrary scenario in which water and life slowly reclaim these arid places…
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.
Farouk el-Baz, director of the Centre for Remote Sensing at Boston University, believes the Sahara is experiencing a shift from dryer to wetter conditions.
“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,” Mr 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.”
Satellite images from the last 15 years do seem to show a recovery of vegetation in the Southern Sahara. The broader picture is reinforced by studies carried out in the Namib Desert in Namibia.
For the last few years there has been higher than average rainfall. This is a region with an average rainfall of just 12 millimetres per year – what scientists call “hyper-arid”. Scientists have been measuring rainfall here for the last 60 years.
Last year the local research centre, called Gobabeb, measured 80mm of rain.