Arabic “shore” names Africa’s Sahara-edge transition belt
The Sahel—from Arabic sāḥil, coast or shore—is the hot semi-arid transition between Sahara desert and wetter Sudanian savannas. It stretches about 5,900 kilometres from Atlantic to Red Sea in a belt hundreds to a thousand kilometres wide, covering roughly 3.05 million square kilometres.
Figuratively the name casts the belt as the southern shore of the Sahara’s sea of sand. It is also called the Sahelian acacia savanna after its hardiest trees, and most of it lies between 200 and 400 metres above sea level, broken by separate highland islands such as the Marrah, Aïr and Ennedi massifs.
Grassland and savanna dominate, with patches of woodland and scrub. Annual grasses such as Cenchrus biflorus, Schoenefeldia gracilis and Aristida stipoides carpet the ground fairly continuously, and acacias, above all Acacia tortilis, are the commonest trees. In the long dry season many trees drop their leaves and the grasses die back, while farther north desert shrubs alternate with grassy stretches.
Large grazing herds once roamed here before hunting and competition with livestock cut them down. The Dorcas and red-fronted gazelles, cheetah and lion are now vulnerable, the Dama gazelle and African wild dog endangered, and the scimitar-horned oryx probably gone from the wild; the bubal hartebeest and Pelorovis are extinct. Seasonal wetlands remain vital stopovers for birds migrating within Africa and between Africa and Eurasia.
The climate resembles the Sahara’s in milder form: hot, sunny, dry and breezy most of the year. Rain comes in a short season of four to six months mid-year, varies wildly from one year to the next, and totals between about 200 and 700 millimetres in the interior. Around 80 million people lived in the belt in 2018, one of the fastest-growing populations anywhere, and drought brings recurring food and water shortages, especially in the west.
Source: Sahel
