Sahara

The Sahara is a vast desert that covers much of North Africa. It is the largest hot desert in the world. It stretches across 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 huge desert reaches 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 borders the Sahel, a region of dry grasslands.

For hundreds of thousands of years, the Sahara has changed between being a dry desert and a grassy area. These changes happen over about 20,000 years. They are caused by the way Earth's axis slowly moves as the planet goes around the Sun. This movement changes where rainy seasons, called the North African monsoon, happen.

Geography

The Sahara is a huge desert that covers much of North Africa. It stretches across countries such as Algeria, Chad, Egypt, Mali, Mauritania, Niger, Western Sahara, and Sudan, as well as parts of Morocco and Tunisia. It is one of the largest deserts in the world. The Sahara has many different landscapes, including rocky areas, huge sand seas with tall sand dunes, gravel plains, dry valleys, and salt flats.

The Sahara also has several mountain ranges and volcanic areas. The highest peak is Emi Koussi in Chad. Even though the desert is harsh, some plants grow there, and oases allow life to thrive. Important cities like Nouakchott and Timbuktu are found in this amazing place.

Climate

The Sahara is the world's largest hot desert. It is found in the horse latitudes under the subtropical ridge. Here, air goes down, gets warm, and dries out. This stops clouds and rain from forming.

Because of this, the Sahara is very sunny and dry. It gets lots of sunshine—more than 3,600 hours each year in most places, and even more in some areas. The desert is very hot, with temperatures often above 38°C (100°F) in the hottest months. Sand and ground can get even hotter, sometimes over 80°C (176°F). The temperature can change a lot between day and night, but nights are not usually as cold as many people think.

Ecoregions

The Sahara has several different ecoregions. Each has its own plants and animals because of the climate and land shape.

These include the Atlantic coastal desert. It gets wet air from the ocean, which helps lichens and shrubs grow. The North Saharan steppe and woodlands gets rain in winter, helping shrubs and trees. The big Sahara desert ecoregion is very dry, with sand dunes, stone flat areas, and gravel lands. Other places, like the South Saharan steppe and woodlands, get rain in summer, which lets grasses and herbs grow.

Flora and fauna

The Sahara Desert has many plants and animals that have learned to live with very little water. Plants like acacia trees, palms, and spiny shrubs grow close to the ground to keep from drying out. They store water inside their stems and have long roots to find moisture deep below.

Several interesting animals live in the Sahara, including the fennec fox, addax antelope, and dorcas gazelle. The Saharan cheetah lives here too, though there are very few left. Other animals include monitor lizards, hyraxes, sand vipers, and a small number of African wild dogs. Dromedary camels and goats are common animals that people raise in the area.

History

Scientists have found that North Africa had over 230 wet periods every 21,000 years for the past eight million years.

In the Central Sahara, people made rock art with engravings and paintings maybe as early as 10,000 years ago. The Sahara was much wetter then. We can still see pictures of river animals like crocodiles, especially in Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs, like Afrovenator, Jobaria, and Ouranosaurus, have been found here too. Today, the Sahara has very little vegetation except in the Nile Valley, a few oases, and the northern highlands where plants like the olive tree grow. Changes in Earth's tilt made the Sahara much drier about 5,400 years ago, starting a process called desertification.

We know from archaeology, genetics, and human history that people moved between Sub-Saharan Africa and the Sahara. The Kiffian culture lived in the Sahara between 10,000 and 8,000 years ago during a wetter time called the Neolithic Subpluvial. In 2000, human remains from this culture were found at a place called Gobero in the Ténéré Desert in Niger. The Kiffians were good hunters.

Gobero was found in 2000 by an team led by Paul Sereno who were looking for dinosaur fossils. They found two ancient cultures at the site: the Kiffian culture and the Tenerian culture. The Tenerians had beliefs about spirits.

Uan Muhuggiag was home to people from at least 6,000 years ago until about 2,700 years ago. One big discovery there was the well-preserved mummy of a young boy.

Before the Sahara became a desert about 9,500 years ago, central Sudan had lots of plants and animals. By 5,000 years ago, people in what is now Nubia were growing crops and raising animals. Saharan rock art shows pictures of cattle and people, suggesting they may have had a special respect for cattle, similar to some African societies today.

By 6,000 years ago, people in the southwest corner of Egypt were herding cattle and building big structures. They grew grains and raised animals like cattle, goats, pigs, and sheep.

The Haratin speak Maghrebi Arabic and Berber languages. They are thought to be descendants of the original people who lived in the Sahara.

Around 4,000 years ago, herders in the Sahara began to develop more complex societies during the Pastoral Period. By 1,800 years ago, this culture spread across the Sahara and Sahel regions.

The people of Phoenicia, who lived from 1,200 to 800 years ago, built settlements along the coast of North Africa and traded with the local people.

An urban civilization, the Garamantes, began around 500 years ago in what is now called the Wadi al-Ajal in Fezzan, Libya.

The Byzantine Empire controlled the northern edge of the Sahara from the 5th to the 7th centuries. Later, after the rise of Islam, Islamic influence spread across the Sahara.

European colonialism started in the Sahara in the 19th century. France took control of Algiers in 1830 and later expanded its rule to many parts of the region, including present-day Algeria, Chad, Mali, French Sudan, Timbuktu, Mauritania, Morocco, Niger, and Tunisia.

Many Saharan countries became independent 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.