"Africa's deserts are in retreat," New Scientist magazine said yesterday.

The aerial survey, commissioned by Dutch, German and American overseas aid agencies, shows increased vegetation in northern Burkina Faso, which 20 years ago was experiencing a desertification crisis because of declining rainfall and destructive farming methods.

Scientists suspect that increased rainfall since the droughts of the 1970s and 1980s and better farming techniques have led to the reverse trend and the greening of parts of Africa.

A comparison with archive photos show an increase in vegetation in the past 15 years in southern Mauritania, northern Burkina Faso, north-western Niger, central Chad and much of Sudan and parts of Eritrea.

"Analysts say the gradual greening has been happening since the mid-1980s, though has gone largely unnoticed. Only now is the evidence being pieced together," the magazine added.