Are the deserts getting green?
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.
They think vast, dry regions like the Sahara might soon begin shrinking.
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."
Article continues: http://news.bbc.co.uk/2/hi/africa/8150415.stm