Sahara

The Sahara is a vast desert that covers much of North Africa. It is the largest hot desert in the world, spanning an area of 9,200,000 square kilometres (3,600,000 sq mi). It is only smaller than the deserts of Antarctica and the northern Arctic.

The name "Sahara" comes from the Arabic word for desert. This enormous desert stretches from the Red Sea in the east and the Mediterranean Sea in the north, all the way to the Atlantic Ocean in the west. To the south, it is bordered by the Sahel, a region of dry grasslands.

For hundreds of thousands of years, the Sahara has gone through cycles, shifting between being a dry desert and a grassy savanna. These changes happen over about 20,000 years due to the way Earth's axis slowly moves as the planet orbits the Sun. This movement affects where rainy seasons, known as the North African monsoon, occur.

Geography

The Sahara is a vast desert that stretches across much of North Africa. It covers large parts of countries such as Algeria, Chad, Egypt, Mali, Mauritania, Niger, Western Sahara, and Sudan, along with parts of Morocco and Tunisia. This desert is one of the largest in the world, with diverse landscapes including rocky plateaus, huge sand seas filled with towering sand dunes, gravel plains, dry valleys, and salt flats.

The Sahara also features several mountain ranges and volcanic areas, with the highest peak being Emi Koussi in Chad. Despite its harsh conditions, the desert supports sparse vegetation in some areas and includes oases where life can flourish. Important cities such as Nouakchott and Timbuktu are located within this incredible landscape.

Climate

The Sahara is the world's largest hot desert. It is located in the horse latitudes under the subtropical ridge, where air descends, warms, and dries out, preventing clouds and rain. This makes the Sahara very sunny, dry, and stable with very little rainfall.

The sky is usually clear, and the Sahara receives a lot of sunshine—over 3,600 hours per year in most places, and even more in some areas. The desert is extremely hot, with average high temperatures often above 38°C (100°F) during the hottest months. Sand and ground temperatures can get even hotter, sometimes reaching over 80°C (176°F). The desert also has big temperature changes between day and night, but nights are not usually as cold as people think.

Ecoregions

The Sahara contains several distinct ecoregions, each with its own plants and animals due to differences in climate and landscape.

These include the Atlantic coastal desert, which gets moisture from ocean fog and supports lichens and shrubs. The North Saharan steppe and woodlands area has winter rains that help shrubs and trees grow. The large Sahara desert ecoregion is extremely dry, featuring sand dunes, stone plateaus, and gravel plains. Other regions, like the South Saharan steppe and woodlands, receive summer rains that allow grasses and herbs to thrive.

Flora and fauna

The Sahara Desert is home to many different plants and animals that have adapted to its dry conditions. Plants such as acacia trees, palms, and spiny shrubs grow low to the ground to avoid losing water. They store water in their stems and have long roots to reach moisture.

Several interesting animals live in the Sahara, including the fennec fox, addax antelope, and dorcas gazelle. The Saharan cheetah is also found here, though there are fewer than 250 left. Other animals include monitor lizards, hyraxes, sand vipers, and small populations of African wild dogs. Dromedary camels and goats are common domesticated animals in the region.

History

Scientists have identified more than 230 humid periods in North Africa, occurring every 21,000 years for the past eight million years.

In the Central Sahara, engraved and painted rock art were created perhaps as early as 10,000 years ago. The Sahara was then a much wetter place than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive, with half found in the Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs, including Afrovenator, Jobaria and Ouranosaurus, have also been found here. The modern Sahara, though, is not lush in vegetation, except in the Nile Valley, at a few oases, and in the northern highlands, where Mediterranean plants such as the olive tree are found to grow. Shifts in Earth's axis increased temperatures and decreased precipitation, which caused an abrupt beginning of North Africa desertification about 5,400 years ago.

Accumulated sources of archaeological, genetic and anthropological evidence have confirmed early migratory flows and cultural influences from Sub-Saharan Africa into the Sahara and North African regions. The Kiffian culture existed between 10,000 and 8,000 years ago in the Sahara, during the Neolithic Subpluvial. Human remains from this culture were found in 2000 at a site known as Gobero, located in Niger in the Ténéré Desert. The Kiffians were skilled hunters.

Gobero was discovered in 2000 during an archaeological expedition led by Paul Sereno, which sought dinosaur remains. Two distinct prehistoric cultures were discovered at the site: the early Holocene Kiffian culture, and the middle Holocene Tenerian culture. Graves show that the Tenerians observed spiritual traditions.

Uan Muhuggiag appears to have been inhabited from at least the 6th millennium BCE to about 2700 BCE. The most noteworthy find at Uan Muhuggiag is the well-preserved mummy of a young boy of approximately 2+1⁄2 years old.

During the Neolithic Era, before the onset of desertification around 9500 BCE, the central Sudan had been a rich environment supporting a large population ranging across what is now barren desert, like the Wadi el-Qa'ab. By the 5th millennium BCE, the people who inhabited what is now called Nubia were full participants in the "agricultural revolution", living a settled lifestyle with domesticated plants and animals. Saharan rock art of cattle and herdsmen suggests the presence of a cattle cult like those found in Sudan and other pastoral societies in Africa today.

By 6000 BCE predynastic Egyptians in the southwestern corner of Egypt were herding cattle and constructing large buildings. Subsistence in organized and permanent settlements in predynastic Egypt by the middle of the 6th millennium BCE centered predominantly on cereal and animal agriculture: cattle, goats, pigs and sheep.

The Haratin speak Maghrebi Arabic dialects and Berber languages. They are believed to largely descend from native ancient black populations that inhabited the Sahara.

In 4000 BCE, the start of sophisticated social structure developed among herders amid the Pastoral Period of the Sahara. Saharan pastoral culture was intricate. By 1800 BCE, Saharan pastoral culture expanded throughout the Saharan and Sahelian regions.

The people of Phoenicia, who flourished from 1200 to 800 BCE, created a chain of settlements along the coast of North Africa and traded extensively with its inhabitants.

An urban civilization, the Garamantes, arose around 500 BCE in the Sahara, in a valley that is now called the Wadi al-Ajal in Fezzan, Libya.

The Byzantine Empire ruled the northern shores of the Sahara from the 5th to the 7th centuries. After the Muslim conquest of Arabia, specifically the Arabian peninsula, the Muslim conquest of North Africa began in the mid-7th to early 8th centuries and Islamic influence expanded rapidly on the Sahara.

European colonialism in the Sahara began in the 19th century. France conquered the regency of Algiers from the Ottomans in 1830, and French rule spread south from French Algeria and eastwards from Senegal into the upper Niger to include present-day Algeria, Chad, Mali then French Sudan including Timbuktu (1893), Mauritania, Morocco (1912), Niger, and Tunisia (1881).

Most of the Saharan states achieved independence after World War II: Libya in 1951; Morocco, Sudan, and Tunisia in 1956; Chad, Mali, Mauritania, and Niger in 1960; and Algeria in 1962.

Peoples and languages

The Sahara is home to many different groups of people. Some of these groups include the Amazigh, such as the Tuareg, and the Sahrawis, who speak a language called Hassaniya. Other groups include the Toubou, Nubians, Zaghawa, Kanuri, Hausa, Songhai, Beja, and Fula/Fulani.

Today, most people in the Sahara speak Arabic dialects. Other languages spoken there include Amazigh and Beja languages. These languages belong to a larger family called Afro-Asiatic.