The Sahara is a desert located in North Africa. It covers an area of 9,200,000 square kilometers (3,600,000 square miles), making it the largest hot desert in the world and the third largest desert overall, after the deserts in Antarctica and the Arctic.
The name “Sahara” comes from the Arabic word for “desert.” The desert spans many countries in North Africa, excluding fertile areas along the Mediterranean Sea, the Atlas Mountains, and the Nile Valley in Egypt and Sudan. It stretches from the Red Sea in the east and the Mediterranean Sea in the north to the Atlantic Ocean in the west, where the landscape shifts from desert to coastal plains. To the south, it meets the Sahel, a semi-arid region around the Niger River valley and Sudan.
The Sahara can be divided into several regions, such as the western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains, the Ténéré Desert, and the Libyan Desert. For many thousands of years, the Sahara has shifted between desert and savanna grassland in cycles lasting about 20,000 years. This change is due to the tilt of Earth’s axis as it orbits the Sun, affecting North Africa’s rainfall patterns.
The Sahara includes large parts of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, Western Sahara, and Sudan, as well as some areas in southern Morocco and Tunisia. It takes up 31% of Africa. If we include regions with less than 250 mm (9.8 in) of rain each year, the Sahara expands to 11 million square kilometers (4,200,000 square miles). It is one of three main regions of the African continent’s geography. The Sahara is so large and reflective that, with advanced technology, it could be spotted from other stars.
The Sahara is mostly made up of rocky plateaus, known as Hamada. Contrary to common belief, sand dunes, called ergs, cover only a small part of the desert, although some dunes can reach over 180 meters (590 feet) high. The features of the desert, like sand dunes and dry valleys, are shaped by wind and rare rainfall. Unique landforms include the Richat Structure in Mauritania.
Deep mountains, many of which are volcanic, rise within the desert. These include the Aïr Mountains, Ahaggar Mountains, Saharan Atlas, Tibesti Mountains, Adrar des Iforas, and the Red Sea Hills. The highest peak is Emi Koussi, a volcano in the Tibesti range of northern Chad.
The central part of the Sahara is very dry, with little vegetation. In the northern and southern areas, as well as in the highlands, there is sparse grass and desert shrubs, with occasional trees in valleys, where moisture collects. The central region contains subdivisions such as the Tanezrouft, the Ténéré, the Libyan Desert, the Eastern Desert, and the Nubian Desert. These very dry areas often go for years without rain.
To the north, the Sahara reaches the Mediterranean Sea in Egypt and parts of Libya. In regions like Cyrenaica and the Maghreb, it meets Mediterranean forest areas that have a hot summer and cool, rainy winters. The northern limit of the Sahara aligns with the northern limit for date palm farming and the southern limit for esparto grass, typical of Mediterranean climates. This limit also corresponds to areas that receive about 100 mm (3.9 inches) of rainfall annually.
To the south, the Sahara borders the Sahel, a dry tropical savanna that stretches across Africa from east to west and has a rainy season in summer. The southern limit of the Sahara can be identified by a specific drought-resistant plant. Climatologically, this limit corresponds to areas with an average annual rainfall of about 150 mm (5.9 inches).
Important cities in the Sahara include Nouakchott, Tamanrasset, Ouargla, Béchar, Hassi Messaoud, Ghardaïa, El Oued in Algeria, Timbuktu in Mali, Agadez in Niger, Ghat in Libya, and Faya-Largeau in Chad.
The Sahara is the world’s largest hot desert and is located in the horse latitudes, beneath a significant belt of warm air that leads to its dry conditions.
Image Credit By M.Bitton – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=127898221
