The southern Saharan desert is in retreat, making farming viable again in what were some of the most arid parts of Africa.
A separate analysis of satellite images completed this summer reveals that dunes are retreating right across the Sahel region on the southern edge of the Sahara desert. Vegetation is ousting sand across a swathe of land stretching from Mauritania on the shores of the Atlantic to Eritrea 6000 kilometres away on the Red Sea coast.
Nor is it just a short-term trend. 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.