Dark and lighter green: Definition of "Sub-Saharan Africa" as used in the statistics of UN institutions.
Lighter green: However, Sudan is classified as North Africa by United Nations Statistics Division.
Simplified climatic map of Africa: Sub-Saharan Africa consists of the Sahel and the Horn of Africa in the north (yellow), the tropical savannas (light green) and the tropical rainforests (dark green) of Equatorial Africa, and the arid Kalahari Basin (yellow) and the "Mediterranean" south coast (olive) of Southern Africa.
Sub-Saharan Africa is, geographically, the area of the continent of Africa that lies south of the Sahara desert.
According to the UN, it consists of all African countries that are fully or partially located south of the Sahara.
It contrasts with North Africa, whose Arab states are part of the Arab world.
Somalia, Djibouti, Comoros and Mauritania are geographically part of Sub-Saharan Africa, but are Arab states and a part of the Arab world.
the Saharan and Sub-Saharan regions of Africa have been separated by the extremely harsh climate of the sparsely populated Sahara, forming an effective barrier interrupted by only the Nile River in Sudan, though the Nile was blocked by the river's cataracts.
The Sahara pump theory explains how flora and fauna (including Homo sapiens) left Africa to penetrate the Middle East and beyond.
African pluvial periods are associated with a "wet Sahara" phase during which larger lakes and more rivers existed.
The use of the term has been criticized because it refers to the South only by cartography conventions and projects a connotation of inferiority; a vestige of colonialism, which some say, divided Africa into European terms of homogeneity.
In northern Somalia was Barbara or the Bilad al-Barbar ("Land of the Berbers"), which was inhabited by the Eastern Baribah or Barbaroi, as the ancestors of the Somalis were referred to by medieval Arab and ancient Greek geographers, respectively.
Climate zones of Africa, showing the ecological break between the hot desert climate of North Africa and the Horn of Africa (red), the hot semi-arid climate of the Sahel and areas surrounding deserts (orange) and the tropical climate of Central and Western Africa (blue).
Southern Africa has a transition to semi-tropical or temperate climates (green), and more desert or semi-arid regions, centered on Namibia and Botswana.