Sahara Desert – WorldAtlas
Covering a vast area of 9,200,000 km², the Sahara Desert is considered the largest hot desert in the world and the third largest desert after the polar deserts of Antarctica and the northern Arctic. The Sahara Desert encompasses much of North Africa, occupying about 31% of the entire African continent. The Sahara Desert covers vast areas of 11 North African countries including Algeria, Egypt, Mali, Morocco, Western Sahara, Tunisia, Chad, Libya, Mauritania, Niger and Sudan within its borders. The name of the Sahara Desert is derived from the Arabic word ‘sahra’ which means ‘desert.’
The vast Sahara Desert is approximately 4,800 km long and has a maximum width of 1,800 km. The desert is bounded by the Mediterranean Sea and the Atlas Mountains on the north side; the Red Sea on the eastern side; the Atlantic Ocean to the west and the semi-arid Sahel region to the south. The Sahel region serves as a transition zone between the hot desert in the north and the humid savannas of sub-Saharan Africa in the south.
The Sahara Desert includes several topographical features such as hard rocky plateaus, craggy mountains, vast plains covered with sand and gravel, salt marshes, seas of sand, sand sheets, dry valleys, filled basins. seasonally, dry lakes, high dunes and huge oasis depressions. The dunes of the Sahara Desert reach a height of 183 m and cover about 15% of the entire desert area. In addition to this, there are numerous volcanic massifs in the Sahara Desert, including the Air Mountains, the Saharan Atlas, the Adrar des Iforas, the Ahaggar Mountains, the Red Sea Hills and the Tibesti. Located at the south-eastern end of the Tibesti Mountains, in the northern part of Chad, is a shield volcano named Emi Koussi, which rises to 3,415m and is the highest point in the Sahara Desert. Located in Egypt, the Qattara Depression is the lowest point of the Sahara Desert, which reaches 133 m below sea level.
Although water sources are quite scarce throughout the desert region, there are 2 major rivers and around 20 seasonal lakes and aquifers in the Sahara Desert. The major rivers of the Nile and the Niger as well as the seasonal lakes and aquifers are the main source of water for the main desert oases. The Sahara Desert is further subdivided into many smaller deserts such as Nubian Desert, Tanezrouft Desert, Sinai Desert, Libyan Desert, Tenere Desert etc. Some of the important African cities located in the Sahara Desert include El Oued in Algeria, Cairo in Egypt, Timbuktu in Mali, Faya-Largeau in Chad, Ghat in Libya, Nouakchott in Mauritania and Agadez in Niger.
According to Köppen’s climate classification, the vast Sahara Desert experiences a hot desert climate. The sky over the desert region generally remains fairly clear and, therefore, the permanent absence of clouds allows for unhindered high sunshine duration over the entire desert area. Strong sun exposure, lack of vegetation and extremely low rainfall make the Sahara Desert one of the hottest regions in the world. During the warmer months, the average high temperature varies between 38 ° and 40 ° C. The highest temperature in the Sahara Desert was recorded at around 58 ° C in Aziziyah, Libya. The night temperature varies between 13 ° and 20 ° C. In winter, temperatures drop below freezing at night. The Sahara Desert receives extremely low precipitation, with precipitation being very unreliable and extremely irregular. Annual evaporation rates are relatively much higher, ranging from 2,500 mm to over 6,000 mm throughout the Sahara Desert region.
The Sahara Desert contains many ecological regions or ecoregions. These are as follows: The Atlantic Coastal Desert Ecoregion covers an area of 39,900 km² along the Atlantic coast in the western part of the Sahara Desert. The Northern Sahara Steppes and Forests ecoregion covers an area of 1,675,300 km² along the northern part of the Sahara Desert. The Sahara Desert ecoregion covers an area of 4,639,900 km² in the central part of the Sahara Desert. The steppes and forests of the south of the Sahara ecoregion covers an area of 1,101,700 km² and stretches from east to west between the hot Sahara desert and the humid savannas of the Sahel. The Western Sahara Xerian Mountain Forest ecoregion covers an area of approximately 258,100 km² and encompasses many areas of the volcanic highlands of the Sahara Desert. The Tibesti-Jebel Uweinat Mountain Xeric Forest Ecoregion covers an area of approximately 54,000 km² in the eastern parts of the Sahara Desert.
As mentioned above, the Sahara Desert experiences extremely harsh climatic conditions and as a result the desert supports only the plants and animals that can survive in its extremely dry and hot climate. It has been recorded that there are around 2,800 species of vascular plants in the Sahara Desert, of which a quarter of these plants are endemic to the region. More than 500 species of plants are found in the central Sahara region. Some of these important plants include acacias, succulents, Sahara cypress, grasses, Laperrine olive, date palms, tamarisk, thorny shrubs, desert thyme, etc. These plants have adapted to the arid conditions of the Sahara Desert by becoming shorter to avoid water loss by strong winds. Additionally, these plants store water in their thick stems which they can use during dry spells, and have also developed long roots that can travel horizontally in search of surface moisture. Plants also have small, thick leaves to prevent water loss through evapotranspiration.
It has been recorded that around 100 reptilian species, 90 avian species, 70 mammal species and a wide range of different animal species are found in the Sahara desert. Some of the main animals that are found in the Sahara Desert include desert foxes, addax antelopes, gazelles, Sahara cheetah, African wild dog, hyrax, deathstalker scorpion, silver ant of the Sahara, camels and dromedary goats, sand vipers, monitor lizards, desert crocodiles. , etc. Notable avian species like the red-necked ostrich, African silver beak, black-faced chaffinch, etc. are also found in the Sahara Desert.
Several studies have revealed that since the end of the last Ice Age, several people have lived on the edge of the Sahara Desert. Archaeologists have discovered numerous petroglyphs in the central part of the Sahara Desert that date back thousands of years. The Kiffian civilization was one of the oldest civilizations in the Sahara Desert. After the Kiffians, the region was inhabited by peoples of several cultures including the Tenerans, the Tashwinat Mummy, the Nubians, etc. Around 6000 BCE, the Egyptians arrived in the Sahara region and began to practice agriculture and herding cattle. It is believed that at that time the Sahara region was green and was home to a large number of plants and animals. But, about 5,400 years ago, the gradual shifting of the Earth’s axis led to an increase in temperature, decrease in precipitation and an extension of desertification in the Sahara region. From 1200 to 800 BC, the region was occupied by the Phoenicians, then in later years by the Greeks, Garamantes, Romans, Berbers, Byzantines and Ottomans. In the 19e century, Europeans began to colonize the Sahara region. After the end of World War II, most of the Saharan states gained independence.