Sahara

The Sahara is the world's largest desert, over 9,000,000 km² (3,500,000 mi²), about the same size as the United States. The Sahara is located in northern Africa and is 2.5 million years old. Its name, Sahara, is an English pronunciation of the word for desert in Arabic (صحراء arabic pronunciation ( help· info)).

Overview

The boundaries of the Sahara are the Atlantic Ocean on the west, the Atlas Mountains and the Mediterranean Sea on the north, the Red Sea and Egypt on the east, and the Sudan and the valley of the Niger River on the south. The Sahara is divided into western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains (a region of desert mountains and high plateaus), Tenere desert and the Libyan desert (the most arid region). The highest peak in the Sahara is Emi Koussi (3415 m) in the Tibesti Mountains in northern Chad.

The Sahara divides the continent of Africa into North and Sub-Saharan Africa. The southern border of the Sahara is marked by a band of semiarid savanna called the Sahel; south of the Sahel lies the lusher Sudan and the Congo River Basin.

Humans have lived on the edge of the desert for almost 500,000 years. During the last ice age, the Sahara was a much wetter place than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive in total with half found in the Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs, like Afrovenator, have also been found here. The modern Sahara, though, is not as 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 grow. It has been this way since about 3000 BC.

2.5 million people live in the Sahara, most of these in Egypt, Mauritania, Morocco and Algeria. Dominant groups of people are the Tuareg- Berber, the Sahrawis, and different black African ethnicities including the Tubu, the Nubians, the Zaghawas and the Kanuri. The largest city is Cairo, Egypt's capital. Other important cities are Nouakchott, the capital of Mauritania, Tamanrasset, Algeria; Timbuktu, Mali; Agadez, Niger; Ghat, Libya; and Faya, Chad.

History

Cattle Period

The domestication of the pig (see [1]) in the Sahara and ancient Egypt has been cited as a likely primary contributor to the desertification of the Sahara (see Sahara Desert (ecoregion)).

By 6000 BC 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 BC centered predominantly on cereal and animal agriculture: cattle, goats, pigs and sheep [2]. Metal objects replaced prior ones of stone [3]. Tanning animal skins, pottery and weaving are commonplace in this era also [4]. There are indications of seasonal or only temporary occupation of the Al Fayyum in the 6th millennium BC, with food activities centering on fishing, hunting and food-gathering [5]. Stone arrowheads, knives and scrapers are common [6]. Burial items include pottery, jewelry, farming and hunting equipment, and assorted foods including dried meat and fruit [7]. The dead are buried facing due west [8].

Berber Period

The use and forging of iron came about from trade with the Phoenicians (c. 1220 BC). They created a confederation of kingdoms across the entire Sahara to Egypt, generally settling on the coasts but sometimes in the desert also.

By 2500 BC the Sahara was as dry as it is today and it became a largely impenetrable barrier to humans, with only scattered settlements around the oases, but little trade or commerce through the desert. The one major exception was the Nile Valley. The Nile, however, was impassable at several cataracts making trade and contact difficult. Over time Egypt spread south and technologies such as iron working, and perhaps ideas such as that of monarchy spread into Nubia and further south.

Sometime between 633 and 530 BC Hanno the Navigator either established or reinforced Phoenician colonies in the Western Sahara, but all ancient remains have vanished with virtually no trace. See History of Western Sahara.

By 500 BC a new influence arrived in the form of the Greeks and Phoenicians. Greek traders spread along the eastern coast of the desert, establishing trading colonies along the Red Sea coast. The Carthaginians explored the Atlantic coast of the desert. The turbulence of the waters and the lack of markets never led to an extensive presence further south than modern Morocco. Centralized states thus surrounded the desert on the north and east; it remained outside of the control of these states. Raids from the nomadic Berber people of the desert were a constant concern of those living on the edge of the desert.

The greatest change in the history of the Sahara arrived with the Arab invasion that brought camels to the region. For the first time an efficient trade across the Sahara desert could be conducted. The kingdoms of the Sahel, especially the Ghana Empire and the later Mali Empire, grew rich and powerful exporting gold and salt to North Africa. The emirates along the Mediterranean sent south manufactured goods and horses. From the Sahara itself salt was exported. This process turned the scattered oasis communities into trading centres, and brought them under the control of the empires on the edge of the desert.

This trade persisted for several centuries until the development in Europe of the caravel allowed ships, first from Portugal but soon from all Western Europe, to sail around the desert and gather the resources from the source in Guinea. The Sahara was rapidly remarginalized.

The colonial powers also largely ignored the region, but the modern era has seen a number of mines and communities develop to exploit the desert's natural resources. These include large deposits of oil and gas in Algeria and Libya and large deposits of phosphates in Morocco and Western Sahara.

mtDNA analyses (see Z. Brakez et al., "Human mitochondrial DNA sequence variation in the Moroccan population of the Souss area" extract) found that various populations have contributed to the present-day gene pool of the Souss region of southern Morocco, including Berbers, Arabs, Phoenicians, Sephardic Jews, and sub-Saharan Africans. Throughout the Sahara, Berbers, Arabs, and sub-Saharan Africans are significantly represented genetically.