128-569: The Tindouf Basin is a major sedimentary basin in West Africa , to the south of the little Atlas region, Morocco . It stretches from west to east about 700 kilometres (430 mi) and covers about 100,000 square kilometres (39,000 sq mi), mostly in Algeria but with a western extension into Morocco and Western Sahara . In the Ordovician period (490 Ma to 445 Ma) the area
256-552: A fertility statuette, created in the region of Senegambia , and may be associated with the emergence of complexly organized pastoral societies in West Africa between 4000 BCE and 1000 BCE. Though possibly developed as early as 5000 BCE, Nsibidi may have also developed in 2000 BCE, as evidenced by depictions of the West African script on Ikom monoliths at Ikom , in Nigeria . Migration of Saharan peoples south of
384-518: A Dutch writer, describing Benin in his book Description of Africa (1668) ". Its craft was the most adored and treasured bronze casting in the history of Africa. It was annexed by the British Empire in 1897 during the invasion and scramble of Africa. Portuguese traders began establishing settlements along the coast in 1445, followed by the French , English , Spanish , Danish and Dutch ;
512-426: A consequence, the weather tends to be sunny, dry and stable with a minimal chance of rainfall. Subsiding, diverging, dry air masses associated with subtropical high-pressure systems are extremely unfavorable for the development of convectional showers. The subtropical ridge is the predominant factor that explains the hot desert climate ( Köppen climate classification BWh ) of this vast region. The descending airflow
640-736: A continental Cretaceous and Pliocene Hamada cover. The basin may have potential for oil and/or gas production, but has been largely unexplored (about 15 billions of barrel and 3000 km3 of gas) most of these reserves in algeria. West Africa West Africa , also called Western Africa , is the westernmost region of Africa . The United Nations defines Western Africa as the 16 countries of Benin , Burkina Faso , Cape Verde , The Gambia , Ghana , Guinea , Guinea-Bissau , Ivory Coast , Liberia , Mali , Mauritania , Niger , Nigeria , Senegal , Sierra Leone , and Togo , as well as Saint Helena, Ascension and Tristan da Cunha ( United Kingdom Overseas Territory ). The population of West Africa
768-635: A fisheries regulations Act in 2010 and installed a satellite-based monitoring system and Senegal enacted a fisheries code in 2015. In Cape Verde, the fishermen communities of Palmiera and Santa Maria have organized themselves to protect fishing zones. Mozambique finally created a conservation area, including a coastline. West Africa, broadly defined to include the western portion of the Maghreb ( Western Sahara , Morocco , Algeria , and Tunisia ), occupies an area in excess of 6,140,000 km , or approximately one-fifth of Africa. The vast majority of this land
896-519: A healthy adult. The Saharan silver ant is unique in that due to the extreme high temperatures of their habitat, and the threat of predators, the ants are active outside their nest for only about ten minutes per day. Dromedary camels and goats are the domesticated animals most commonly found in the Sahara. Because of its qualities of endurance and speed, the dromedary is the favourite animal used by nomads . Human activities are more likely to affect
1024-612: A result of increasing aridification of the Green Sahara , Central Saharan hunter-gatherers and cattle herders may have used seasonal waterways as the migratory route taken to the Niger River and Chad Basin of West Africa. In 2000 BCE, " Thiaroye Woman", also known as the " Venus of Thiaroye", may have been the earliest statuette created in Sub-Saharan West Africa; it may have particularly been
1152-617: A rich array of biomes , from biodiversity-rich tropical forests to drylands supporting rare and endangered fauna such as pangolins , rhinoceros , and elephants . Because of the pressure for economic development, many of these ecologies are threatened by processes like deforestation , biodiversity loss , overfishing , pollution from mining , plastics and other industries, and extreme changes resulting from climate change in West Africa . The history of West Africa can be divided into five major periods: first, its prehistory, in which
1280-554: A subgroup of the Igbo people. The Kingdom of Nri was unusual in the history of world government in that its leader exercised no military power over his subjects. The kingdom existed as a sphere of religious and political influence over a third of Igboland and was administered by a priest-king called an Eze Nri . The Eze Nri managed trade and diplomacy on behalf of the Nri people and possessed divine authority in religious matters. The Oyo Empire
1408-569: A summer rainy season that extends across Africa from east to west. The southern limit of the Sahara is indicated botanically by the southern limit of Cornulaca monacantha (a drought-tolerant member of the Chenopodiaceae ), or northern limit of Cenchrus biflorus , a grass typical of the Sahel. According to climatic criteria, the southern limit of the Sahara corresponds to the 150 mm (5.9 in) isohyet of annual precipitation (this
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#17327731457161536-542: A surface feature of Earth, with near-current technology. The Sahara is mainly rocky hamada (stone plateaus); ergs (sand seas – large areas covered with sand dunes ) form only a minor part, contrary to common misconception , but many of the sand dunes are over 180 metres (590 ft) high. Wind or rare rainfall shape the desert features: sand dunes, dune fields, sand seas, stone plateaus, gravel plains ( reg ), dry valleys ( wadi ), dry lakes ( oued ), and salt flats ( shatt or chott ). Unusual landforms include
1664-660: Is a long-term average, since precipitation varies annually). Important cities located in the Sahara include Nouakchott , the capital of Mauritania; Tamanrasset , Ouargla , Béchar , Hassi Messaoud , Ghardaïa , and 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 . It is located in
1792-422: Is a north African gazelle that can also go for a long time without water. Other notable gazelles include the rhim gazelle and dama gazelle . The Saharan cheetah ( northwest African cheetah ) lives in Algeria, Togo , Niger, Mali, Benin , and Burkina Faso . There remain fewer than 250 mature cheetahs, which are very cautious, fleeing any human presence. The cheetah avoids the sun from April to October, seeking
1920-629: Is a prehistoric industry, or domain, that 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 site is known as the largest and earliest grave of Stone Age people in the Sahara. The Kiffians were skilled hunters . Bones of many large savannah animals that were discovered in
2048-497: Is a transnational highway project to link 12 West African coastal states, from Mauritania in the north-west of the region to Nigeria in the east, with feeder roads already existing to two landlocked countries, Mali and Burkina Faso . The eastern end of the highway terminates at Lagos , Nigeria . Economic Community of West African States (ECOWAS) consider its western end to be Nouakchott , Mauritania , or to be Dakar , Senegal , giving rise to these alternative names for
2176-465: Is associated with high rates of wind-blown mineral dust, and these dust levels are found as expected in marine cores from the north tropical Atlantic. But around 12,500 BCE the amount of dust in the cores in the Bølling / Allerød phase suddenly plummets and shows a period of much wetter conditions in the Sahara, indicating a Dansgaard-Oeschger (DO) event (a sudden warming followed by a slower cooling of
2304-458: Is estimated at 419 million people as of 2021, and at 381,981,000 as of 2017, of which 189,672,000 were female and 192,309,000 male. The region is demographically and economically one of the fastest growing on the African continent. Early history in West Africa includes a number of prominent regional powers that dominated different parts of both the coastal and internal trade networks, such as
2432-403: Is estimated to include five hundred species of plants, which is extremely low considering the huge extent of the area. Plants such as acacia trees, palms, succulents, spiny shrubs, and grasses have adapted to the arid conditions, by growing lower to avoid water loss by strong winds, by storing water in their thick stems to use it in dry periods, by having long roots that travel horizontally to reach
2560-625: Is plains lying less than 300 meters above sea level, though isolated high points exist in numerous states along the southern shore of West Africa. Benin Burkina Faso The Gambia Ghana Guinea-Bissau Guinea Ivory Coast Liberia Mali Mauritania Nigeria Niger Senegal Sierra Leone Togo The northern section of West Africa (narrowly defined to exclude
2688-463: Is rather majestic and looks like a huge phallus and a deformed animal or thing is protruding from it. It is said to be the dwelling place of a pangool . Ngoye njuli is protected by the Senegalese authorities and attracts visitors. In West Africa, as in other parts of Africa where the baobab tree is found, the leaves are mixed with couscous and eaten, the bark of the tree is used to make ropes, and
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#17327731457162816-407: Is the largest hot desert in the world and the third-largest desert overall, smaller only than the deserts of Antarctica and the northern Arctic . The name "Sahara" is derived from Arabic : صَحَارَى , romanized : ṣaḥārā /sˤaħaːraː/ , a broken plural form of ṣaḥrā' ( صَحْرَاء /sˤaħraːʔ/ ), meaning "desert". The desert covers much of North Africa , excluding
2944-667: Is the strongest and the most effective over the eastern part of the Great Desert, in the Libyan Desert: this is the sunniest, driest and the most nearly "rainless" place on the planet, rivaling the Atacama Desert , lying in Chile and Peru . The rainfall inhibition and the dissipation of cloud cover are most accentuated over the eastern section of the Sahara rather than the western. The prevailing air mass lying above
3072-422: Is very unreliable and erratic in the Sahara as it may vary considerably year by year. In full contrast to the negligible annual rainfall amounts, the annual rates of potential evaporation are extraordinarily high, roughly ranging from 2,500 millimetres (100 in) per year to more than 6,000 millimetres (240 in) per year in the whole desert. Nowhere else on Earth has air been found as dry and evaporative as in
3200-543: The Adrar of Mauritania and a value of 75 °C (167 °F) has been measured in Borkou , northern Chad. Due to lack of cloud cover and very low humidity, the desert usually has high diurnal temperature variations between days and nights. However, it is a myth that the nights are especially cold after extremely hot days in the Sahara. On average, nighttime temperatures tend to be 13–20 °C (23–36 °F) cooler than in
3328-633: The African slave trade began not long after, which over the following centuries would debilitate the region's economy and population. The slave trade also encouraged the formation of states such as the Bono State , Bambara Empire and Dahomey , whose economic activities include but not limited to exchanging slaves for European firearms . In the early 19th century, a series of Fulani reformist jihads swept across Western Africa. The most notable include Usman dan Fodio 's Fulani Empire , which replaced
3456-488: The Algerian Desert called Bou Bernous , at an elevation of 378 metres (1,240 ft) above sea level, and only Death Valley, California rivals it. Other hot spots in Algeria such as Adrar , Timimoun , In Salah , Ouallene , Aoulef , Reggane with an elevation between 200 and 400 metres (660 and 1,310 ft) above sea level get slightly lower summer average highs, around 46 °C (114.8 °F) during
3584-560: The Benue Trough , and others on a line running from Mount Cameroon to Lake Chad . Colonial boundaries are reflected in the modern boundaries between contemporary West African states, cutting across ethnic and cultural lines, often dividing single ethnic groups between two or more states. In contrast to most of Central, Southern, and Southeast Africa, West Africa is not populated by Bantu -speaking peoples. The West African region can be divided into four climatic sub-regions namely
3712-727: The Hausa city-states, Seku Amadu 's Massina Empire , which defeated the Bambara, and El Hadj Umar Tall 's Toucouleur Empire , which briefly conquered much of modern-day Mali. However, the French and British continued to advance in the Scramble for Africa , subjugating kingdom after kingdom. With the fall of Samory Ture's established Wassoulou Empire in 1898 and the Ashanti queen Yaa Asantewaa in 1902, most West African military resistance to colonial rule resulted in failure. Part of
3840-765: The Late Pleistocene Iberomaurusians , early Holocene Capsians , and mid-Holocene Mechta groups, whereas the Tenerian crania are more like those of Mediterranean groups. Graves show that the Tenerians observed spiritual traditions, as they were buried with artifacts such as jewelry made of hippo tusks and clay pots. The most interesting find is a triple burial, dated to 5300 years ago, of an adult female and two children, estimated through their teeth as being five and eight years old, hugging each other. Pollen residue indicates they were buried on
3968-522: The Mali and Gao Empires . West Africa sat at the intersection of trade routes between Arab -dominated North Africa and further south on the continent, the source of specialized goods such as gold , advanced iron-working , and ivory . After European exploration encountered rich local economies and kingdoms, the Atlantic slave trade built on already existing slave systems to provide labor for colonies in
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4096-703: The Niger River valley and the Sudan region of sub-Saharan Africa . The Sahara can be divided into several regions, including the western Sahara, the central Ahaggar Mountains , the Tibesti Mountains , the Aïr Mountains , the Ténéré desert, and the Libyan Desert . For several hundred thousand years, the Sahara has alternated between desert and savanna grassland in a 20,000-year cycle caused by
4224-694: The Richat Structure in Mauritania. Several deeply dissected mountains, many volcanic, rise from the desert, including the Aïr Mountains , Ahaggar Mountains , Saharan Atlas , Tibesti Mountains , Adrar des Iforas , and the Red Sea Hills . The highest peak in the Sahara is Emi Koussi , a shield volcano in the Tibesti range of northern Chad. The central Sahara is hyperarid , with sparse vegetation. The northern and southern reaches of
4352-751: The Senegambia region (Senegal and the Gambia) used to have a diverse wildlife including lions , hippopotamus , elephants , antelopes , leopards etc. However, during colonization, the European colonizers such as the French and British killed most of the wildlife particularly the lions, using their body parts as trophies. By the turn of the 20th century, the Senegambia region had lost most of its lion population and other exotic animals due to poaching . By
4480-459: The forest-savanna region, were ultimately acculturated and admixed into the larger groups of West African agriculturalists , akin to the migratory Bantu -speaking agriculturalists and their encounters with Central African hunter-gatherers . The development of the region's economy allowed more centralized states and civilizations to form, beginning with Dhar Tichitt that began in 1600 B.C. followed by Djenné-Djenno beginning in 300 B.C. This
4608-474: The horse latitudes under the subtropical ridge , a significant belt of semi-permanent subtropical warm-core high pressure where the air from the upper troposphere usually descends, warming and drying the lower troposphere and preventing cloud formation. The permanent absence of clouds allows unhindered light and thermal radiation. The stability of the atmosphere above the desert prevents any convective overturning, thus making rainfall virtually non-existent. As
4736-514: The precession of Earth's axis (about 26,000 years) as it rotates around the Sun, which changes the location of the North African monsoon . The Sahara covers large parts of Algeria , Chad , Egypt , Libya , Mali , Mauritania , Niger , Western Sahara and Sudan , and parts of southern Morocco and Tunisia . It covers 9 million square kilometres (3,500,000 sq mi), 31% of
4864-576: The 10th-century Kingdom of Nri , which helped birth the arts and customs of the Igbo people , Bono State in the 11th century, which gave birth to the numerous Akan States, while Ife rose to prominence around the 12th century. Further east, Oyo arose as the dominant Yoruba state and the Aro Confederacy as a dominant Igbo state in modern-day Nigeria. The Kingdom of Nri was a West African medieval state in present-day southeastern Nigeria and
4992-494: The 1930s, the Gambian elephant population became extinct. That phenomenon was not only limited to the Senegambia region but affected much of West Africa as the region lost much of its "natural resources once tied so closely to its cultural identity. Poaching has stolen most of its wildlife." The British issued poaching licenses, and although they would later try to reverse the damage that had been done by attempting to preserve what
5120-418: The 1950s. Some have identified the two recent decades as a recovery period. Others refer to this as a period of "hydrological intensification" with much of the annual rainfall increase coming from more severe rain events and sometimes flooding rather than more frequent rainfall, or similarly other works underline the continuity of the drought even though the rainfall has increased. Since 1985, 54 percent of
5248-400: The African continent. If all areas with a mean annual precipitation of less than 250 mm (9.8 in) were included, the Sahara would be 11 million square kilometres (4,200,000 sq mi). It is one of three distinct physiographic provinces of the African massive physiographic division . The Sahara is so large and bright that, in theory, it could be detected from other stars as
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5376-417: The African humid period. At its largest extent, sometime before 5000 BCE, Lake Mega-Chad was the largest of four Saharan paleolakes, and is estimated to have covered an area of 350,000 km . The Sahara pump theory describes this cycle. During periods of a wet or " Green Sahara ", the Sahara becomes a savanna grassland and various flora and fauna become more common. Following inter-pluvial arid periods,
5504-601: The Americas. After the end of the slave trade in the early 19th century , European nations, especially France and Britain , continued to exploit the region through colonial relationships . For example, they continued exporting a number of extractive goods , including labor-intensive agricultural crops like cocoa and coffee , forestry products like tropical timber , and mineral resources like gold. Since independence, many West African countries, like Ivory Coast , Ghana , Nigeria and Senegal , have played important roles in
5632-668: The Atlantic. Due to Mauritania's increasingly close ties to the Arab World and its 1999 withdrawal from the Economic Community of West African States (ECOWAS), in modern times it is often considered, especially in Africa, as now part of western North Africa . Major and principal cities in West Africa include, geographically eastward: Before European colonisation , West African countries such as those from
5760-412: The Great Desert the hottest large region in the world, and the hottest place on Earth during summer in some spots. The average high temperature exceeds 38 to 40 °C (100.4 to 104.0 °F) during the hottest month nearly everywhere in the desert except at very high altitudes. The world's highest officially recorded average daily high temperature was 47 °C (116.6 °F) in a remote desert town in
5888-464: The Guinea Coast associated with a reduction of the wet spells under both 1.5 °C and 2 °C global warming level. A Trans-ECOWAS project, established in 2007, plans to upgrade railways in this zone. One of the goals of the Economic Community of West African States (ECOWAS) is the development of an integrated railroad network. Aims include the extension of railways in member countries,
6016-631: The Guinea Coast, Soudano-Sahel, Sahel (extending eastward to the Ethiopian border) and the Sahara, each with different climatic conditions. The seasonal cycle of rainfall is mainly driven by the south-north movement of the Inter-Tropical Convergence Zone (ITCZ) which is characterised by the confluence between moist southwesterly monsoon winds and the dry northeasterly Harmattan. Based on the inter-annual rainfall variability, three main climatic periods have been observed over
6144-486: The Intertropical Convergence Zone from the south and the annual average rainfall ranges from 100 millimetres (4 in) to 250 millimetres (10 in). For example, Timbuktu, Mali and Agadez , Niger are found in this zone. The vast central hyper-arid core of the desert is virtually never affected by northerly or southerly atmospheric disturbances and permanently remains under the influence of
6272-625: The Ivory Coast, have lost large areas of their rainforest . In 2005, the Food and Agriculture Organization of the United Nations ranked Nigeria as the state with the worst deforestation rate in the entire world. Causes include logging, subsistence agriculture , and the collection of fuelwoods. According to a ThoughtCo publication authored Steve Nix (2018), almost 90 percent of West Africa's original rainforest has been destroyed, and
6400-523: The Kiffian culture do not exist after 8,000 years ago, as the Sahara went through a dry period for the next thousand years. After this time, the Tenerian culture colonized the area. 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
6528-531: The Niger River basin between eastern Ghana and western Nigeria (northern Benin), rice ( oryza glaberrima ) in the Inner Niger Delta region of Mali, pearl millet ( cenchrus americanus ) in northern Mali and Mauritania, and cowpeas in northern Ghana. After having persisted as late as 1000 BP, or some period of time after 1500 CE, remaining West African hunter-gatherers, many of whom dwelt in
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#17327731457166656-462: The Sahara (birds in particular) such as African silverbill and black-faced firefinch , among others. There are also small desert crocodiles in Mauritania and the Ennedi Plateau of Chad. The deathstalker scorpion can be 10 cm (3.9 in) long. Its venom contains large amounts of agitoxin and scyllatoxin and is very dangerous; however, a sting from this scorpion rarely kills
6784-531: The Sahara area then reverts to desert conditions and the flora and fauna are forced to retreat northwards to the Atlas Mountains , southwards into West Africa , or eastwards into the Nile Valley . This separates populations of some of the species in areas with different climates , forcing them to adapt , possibly giving rise to allopatric speciation . It is also proposed that humans accelerated
6912-528: The Sahara is strongly influenced by the North Atlantic Oscillation (NAO), with warmer winter temperatures during negative NAO events and cooler winters with more frosts when the NAO is positive. This is because the weaker clockwise flow around the eastern side of the subtropical anticyclone during negative NAO winters, although too dry to produce more than negligible precipitation, does reduce
7040-504: The Sahara is the continental tropical (cT) air mass, which is hot and dry. Hot, dry air masses primarily form over the North-African desert from the heating of the vast continental land area, and it affects the whole desert during most of the year. Because of this extreme heating process, a thermal low is usually noticed near the surface, and is the strongest and the most developed during the summertime. The Sahara High represents
7168-638: The Sahara region. However, at least two instances of snowfall have been recorded in Sahara, in February 1979 and December 2016, both in the town of Ain Sefra . One theory for the formation of the Sahara is that the monsoon in Northern Africa was weakened because of glaciation during the Quaternary period, starting two or three million years ago. Another theory is that the monsoon was weakened when
7296-545: The Sahel: the wet period from 1950 to the early 1960s followed by a dry period from 1972 to 1990 and then the period from 1991 onwards which has seen a partial rainfall recovery. During the dry period, the Sahel experienced a number of particularly severe drought events, with devastating effects. The recent decades, have also witnessed a moderate increment in annual rainfall since the beginning of 1990s. However, total annual rainfall remains significantly below that observed during
7424-567: The Sahelian region resulted in seasonal interaction with and gradual absorption of West African hunter-gatherers, who primarily dwelt in the savannas and forests of West Africa. In West Africa, which may have been a major regional cradle in Africa for the domestication of crops and animals, Niger-Congo speakers domesticated the helmeted guineafowl between 5500 BP and 1300 BP; domestication of field crops occurred throughout various locations in West Africa, such as yams (d. praehensilis) in
7552-713: 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. The Kiffian culture
7680-514: The West African regions underwent an increase in the numeracy level throughout the 19th century. The reason for such a growth was predetermined by a number of factors. Namely, the peanut production and trade, which was boosted by the demand of the colonial states . Importantly, the rise of numeracy was higher in the regions which were less hierarchical and had less dependence on the slavery trade (e.g. Sine and Salum). Whereas areas with
7808-595: The amount of rainfall received – the Northern (Mediterranean), Central and Southern Zones. There are two transitional zones – the Mediterranean-Sahara transition and the Sahel transition zone. The Saharan flora comprises around 2800 species of vascular plants . Approximately a quarter of these are endemic . About half of these species are common to the flora of the Arabian deserts. The central Sahara
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#17327731457167936-422: The ancient Tethys Sea dried up during the Tortonian period around 7 million years ago. The climate of the Sahara has undergone enormous variations between wet and dry over the last few hundred thousand years, believed to be caused by long-term changes in the North African climate cycle that alters the path of the North African Monsoon – usually southward. The cycle is caused by a 41,000-year cycle in which
8064-435: The archaeology of the city of Kumbi Saleh in modern-day Mauritania, the Mali empire came to dominate much of the region until its defeat by Almoravid invaders in 1052. Three great kingdoms were identified in Bilad al-Sudan by the ninth century. They included Ghana, Gao and Kanem . The Sosso Empire sought to fill the void but was defeated ( c. 1240 ) by the Mandinka forces of Sundiata Keita , founder of
8192-421: The atmospheric circulation itself, the desert is made even drier by its geographical configuration and location. Indeed, the extreme aridity of the Sahara is not only explained by the subtropical high pressure: the Atlas Mountains of Algeria, Morocco and Tunisia also help to enhance the aridity of the northern part of the desert. These major mountain ranges act as a barrier, causing a strong rain shadow effect on
8320-448: The climate). The moister Saharan conditions had begun about 12,500 BCE, with the extension of the ITCZ northward in the northern hemisphere summer, bringing moist wet conditions and a savanna climate to the Sahara, which (apart from a short dry spell associated with the Younger Dryas ) peaked during the Holocene thermal maximum climatic phase at 4000 BCE when mid-latitude temperatures seem to have been between 2 and 3 degrees warmer than in
8448-463: The colony of Guinea-Bissau , while Germany claimed Togoland , but was forced to divide it between France and Britain following First World War due to the Treaty of Versailles . Only Liberia retained its independence, at the price of major territorial concessions. Following World War II , nationalist movements arose across West Africa. In 1957, Ghana, under Kwame Nkrumah , became the first West African colony to achieve its independence, followed
8576-474: The daytime. The smallest variations are found along the coastal regions due to high humidity and are often even lower than a 10 °C (18 °F) difference, while the largest variations are found in inland desert areas where the humidity is the lowest, mainly in the southern Sahara. Still, it is true that winter nights can be cold, as it can drop to the freezing point and even below, especially in high-elevation areas. The frequency of subfreezing winter nights in
8704-469: The desert experiences around three to five months when the average high strictly exceeds 40 °C (104 °F); while in the southern central part of the desert, there are up to six or seven months when the average high temperature strictly exceeds 40 °C (104 °F). Some examples of this are Bilma , Niger and Faya-Largeau, Chad. The annual average daily temperature exceeds 20 °C (68 °F) everywhere and can approach 30 °C (86 °F) in
8832-405: The desert, along with the highlands, have areas of sparse grassland and desert shrub , with trees and taller shrubs in wadis , where moisture collects. In the central, hyperarid region, there are many subdivisions of the great desert: Tanezrouft , the Ténéré , the Libyan Desert , the Eastern Desert , the Nubian Desert and others. These extremely arid areas often receive no rain for years. To
8960-475: The drying-out period from 6000 to 2500 BCE by pastoralists overgrazing available grassland. The growth of speleothems (which requires rainwater) was detected in Hol-Zakh, Ashalim , Even-Sid, Ma'ale-ha-Meyshar, Ktora Cracks, Nagev Tzavoa Cave, and elsewhere, and has allowed tracking of prehistoric rainfall. The Red Sea coastal route was extremely arid before 140 and after 115 kya (thousands of years ago). Slightly wetter conditions appear at 90–87 kya, but it still
9088-401: The earliest pottery in Africa – by at least 9400 BCE, and along with their pottery, as well as wielding independently invented bows and arrows , migrated into the Central Sahara, which became their primary region of residence by 10,000 BP. The emergence and expansion of ceramics in the Sahara may be linked with the origin of Round Head and Kel Essuf rock art, which occupy rockshelters in
9216-667: The eastern continental extension of the Azores High , centered over the North Atlantic Ocean . The subsidence of the Sahara High nearly reaches the ground during the coolest part of the year, while it is confined to the upper troposphere during the hottest periods. The effects of local surface low pressure are extremely limited because upper-level subsidence still continues to block any form of air ascent. Also, to be protected against rain-bearing weather systems by
9344-614: The edge of the desert thousands of years ago, since the end of the last glacial period . In the Central Sahara, engraved and painted rock art were created perhaps as early as 10,000 years ago, spanning the Bubaline Period , Kel Essuf Period , Round Head Period , Pastoral Period , Caballine Period , and Cameline Period . 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
9472-607: The end of colonialism, the region has been the stage for some brutal conflicts, including: Geopolitically , the United Nations definition of subregion Western Africa includes the preceding states with the addition of Mauritania (which withdrew from ECOWAS in 1999), comprising an area of approximately 6.1 million square km. The UN region also includes the United Kingdom Overseas Territory of Saint Helena, Ascension and Tristan da Cunha in
9600-754: The entire region; and fifth, the post-independence era, in which the current nations were formed. West African populations were considerably mobile and interacted with one another throughout the population history of West Africa . Acheulean tool-using archaic humans may have dwelled throughout West Africa since at least between 780,000 BP and 126,000 BP ( Middle Pleistocene ). During the Pleistocene , Middle Stone Age peoples (e.g., Iwo Eleru people , possibly Aterians ), who dwelled throughout West Africa between MIS 4 and MIS 2 , were gradually replaced by incoming Late Stone Age peoples , who migrated into West Africa as an increase in humid conditions resulted in
9728-768: The fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb , and the Nile Valley in Egypt and the Sudan . It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains. To the south it is bounded by the Sahel , a belt of semi-arid tropical savanna around
9856-478: The first human settlers arrived, developed agriculture , and made contact with peoples to the north; the second, the Iron Age empires that consolidated both intra-Africa, and extra-Africa trade, and developed centralized states; third, major polities flourished, which would undergo an extensive history of contact with non-Africans; fourth, the colonial period, in which Great Britain and France controlled nearly
9984-484: The flow of dry, cold air from higher latitudes of Eurasia into the Sahara significantly. The average annual rainfall ranges from very low in the northern and southern fringes of the desert to nearly non-existent over the central and the eastern part. The thin northern fringe of the desert receives more winter cloudiness and rainfall due to the arrival of low pressure systems over the Mediterranean Sea along
10112-579: The fruit and seeds are used for drinks and oils. West Africa is greatly affected by deforestation and has one of the worst deforestation rate. Even "the beloved baobab tree" which is viewed as sacred by some West African cultures are under threat due to climate change , urbanization and population growth. "Huge swaths of forest are being razed to clear space for palm oil and cocoa plantations. Mangroves are being killed off by pollution. Even wispy acacias are hacked away for use in cooking fires to feed growing families." Nigeria, Liberia, Guinea, Ghana and
10240-699: The habitat in areas of permanent water (oases) or where water comes close to the surface. Here, the local pressure on natural resources can be intense. The remaining populations of large mammals have been greatly reduced by hunting for food and recreation. In recent years development projects have started in the deserts of Algeria and Tunisia using irrigated water pumped from underground aquifers. These schemes often lead to soil degradation and salinization . Researchers from Hacettepe University have reported that Saharan soil may have bio-available iron and also some essential macro and micro nutrient elements suitable for use as fertilizer for growing wheat. People lived on
10368-405: The highest recorded worldwide. The sky is usually clear above the desert, and the sunshine duration is extremely high everywhere in the Sahara. Most of the desert has more than 3,600 hours of bright sunshine per year (over 82% of daylight hours), and a wide area in the eastern part has over 4,000 hours of bright sunshine per year (over 91% of daylight hours). The highest values are very close to
10496-551: The hottest months of the year. Salah, well known in Algeria for its extreme heat, has average high temperatures of 43.8 °C (110.8 °F), 46.4 °C (115.5 °F), 45.5 °C (113.9 °F) and 41.9 °C (107.4 °F) in June, July, August and September respectively. There are even hotter spots in the Sahara, but they are located in extremely remote areas, especially in the Azalai , lying in northern Mali. The major part of
10624-491: The hottest regions year-round. However, most of the desert has a value in excess of 25 °C (77 °F). Sand and ground temperatures are even more extreme. During daytime, the sand temperature is extremely high: it can easily reach 80 °C (176 °F) or more. A sand temperature of 83.5 °C (182.3 °F) has been recorded in Port Sudan . Ground temperatures of 72 °C (161.6 °F) have been recorded in
10752-534: The human population relies. West Africa is west of an imagined north-south axis lying close to 10° east longitude . The Atlantic Ocean forms the western as well as the southern borders of the West African region. The northern border is the Sahara Desert , with the Ranishanu Bend generally considered the northernmost part of the region. The eastern border is less precise, with some placing it at
10880-649: The interconnection of previously isolated railways and the standardization of gauge, brakes, couplings, and other parameters. The first line would connect the cities and ports of Lagos , Cotonou , Lomé and Accra and would allow the largest container ships to focus on a smaller number of large ports, while efficiently serving a larger hinterland . This line connects 3 ft 6 in ( 1,067 mm ) gauge and 1,000 mm ( 3 ft 3 + 3 ⁄ 8 in ) metre gauge systems, which would require four rail dual gauge , which can also provide standard gauge . The Trans–West African Coastal Highway
11008-406: The last glacial period , the Sahara was much larger than it is today, extending south beyond its current boundaries. The end of the glacial period brought more rain to the Sahara, from about 8000 BCE to 6000 BCE, perhaps because of low pressure areas over the collapsing ice sheets to the north. Once the ice sheets were gone, the northern Sahara dried out. In the southern Sahara, the drying trend
11136-458: The late nineteenth century, The hypothesis was later formally proposed and tested by the meteorologist John Kutzbach in 1981. Kutzbach's ideas about the impacts of insolation on global monsoonal patterns have become widely accepted today as the underlying driver of long-term monsoonal cycles. Kutzbach never formally named his hypothesis and as such it is referred to here as the " Orbital Monsoon Hypothesis " as suggested by Ruddiman in 2001. During
11264-530: The leeward side by dropping much of the humidity brought by atmospheric disturbances along the polar front which affects the surrounding Mediterranean climates. The primary source of rain in the Sahara is the Intertropical Convergence Zone , a continuous belt of low-pressure systems near the equator which bring the brief, short and irregular rainy season to the Sahel and southern Sahara. Rainfall in this giant desert has to overcome
11392-419: The maximum area of water and to find any surface moisture, and by having small thick leaves or needles to prevent water loss by evapotranspiration . Plant leaves may dry out totally and then recover. Several species of fox live in the Sahara including: the fennec fox , pale fox and Rüppell's fox . The addax , a large white antelope , can go nearly a year in the desert without drinking. The dorcas gazelle
11520-629: The mid-17th to the late 18th century, holding sway not only over most of the other kingdoms in Yorubaland , but also over nearby African states, notably the Fon Kingdom of Dahomey in the modern Republic of Benin to the west. The Benin Empire was a post-classical empire located in what is now southern Nigeria . Its capital was Edo, now known as Benin City , Edo . It should not be confused with
11648-437: The middle Holocene Tenerian culture . The post-Kiffian desiccation lasted until around 4600 BCE, when the earliest artefacts associated with the Tenerians have been dated to. Some 200 skeletons have been discovered at Gobero. The Tenerians were considerably shorter in height and less robust than the earlier Kiffians. Craniometric analysis also indicates that they were osteologically distinct. The Kiffian skulls are akin to those of
11776-474: The modern-day country called Benin , formerly called Dahomey . The Benin Empire was "one of the oldest and most highly developed states in the coastal hinterland of West Africa, dating perhaps to the eleventh century CE". The Benin Empire was governed by a sovereign Emperor with hundreds of thousands of soldiers and a powerful council rich in resources, wealth, ancient science and technology with cities described as beautiful and large as Haarlem . " Olfert Dapper ,
11904-655: The new Mali Empire. The Mali Empire continued to flourish for several centuries, most particularly under Sundiata's grandnephew Musa I , before a succession of weak rulers led to its collapse under Mossi , Tuareg and Songhai invaders. In the 15th century, the Songhai would form a new dominant state based on Gao , in the Songhai Empire , under the leadership of Sonni Ali and Askia Mohammed . Meanwhile, south of Sudan, strong city-states arose in Igboland , such as
12032-514: The next year by France's colonies (Guinea in 1958 under the leadership of President Ahmed Sekou Touré); by 1974, West Africa's nations were entirely autonomous. Since independence, many West African nations have been submerged under political instability, with notable civil wars in Nigeria, Sierra Leone, Liberia, and Ivory Coast, and a succession of military coups in Ghana and Burkina Faso . Since
12160-579: The north, the Sahara skirts the Mediterranean Sea in Egypt and portions of Libya, but in Cyrenaica and the Maghreb , the Sahara borders the Mediterranean forest, woodland, and scrub eco-regions of northern Africa, all of which have a Mediterranean climate characterized by hot summers and cool and rainy winters. According to the botanical criteria of Frank White and geographer Robert Capot-Rey,
12288-477: The northern limit of the Sahara corresponds to the northern limit of date palm cultivation and the southern limit of the range of esparto , a grass typical of the Mediterranean climate portion of the Maghreb and Iberia . The northern limit also corresponds to the 100 mm (3.9 in) isohyet of annual precipitation. To the south, the Sahara is bounded by the Sahel, a belt of dry tropical savanna with
12416-490: The number of registered trawlers operating in African waters, increase the monitoring and control and set up regional fisheries organizations. Some steps have already been taken in the form of WARFP (the World Bank's West Africa Regional Fisheries Program which empowers west-African countries (i.e. Liberia, Sierra Leone, Cape Verde, and Senegal) with information, training and monitoring systems. Furthermore, Liberia enacted
12544-459: The opposite is true, with decreased annual precipitation and less vegetation resulting in a phase of the Sahara climate cycle known as the "desert Sahara". The idea that changes in insolation (solar heating) caused by long-term changes in Earth's orbit are a controlling factor for the long-term variations in the strength of monsoon patterns across the globe was first suggested by Rudolf Spitaler in
12672-453: The opposite trends illustrated opposite tendencies (e.g. central and northern Senegal). Those patterns were further even more stimulated by the French colonial campaign. Britain controlled the Gambia, Sierra Leone, Ghana, and Nigeria throughout the colonial era, while France unified Senegal, Guinea, Mali, Burkina Faso, Benin, Ivory Coast, and Niger into French West Africa . Portugal founded
12800-419: The physical and atmospheric barriers that normally prevent the production of precipitation. The harsh climate of the Sahara is characterized by: extremely low, unreliable, highly erratic rainfall; extremely high sunshine duration values; high temperatures year-round; negligible rates of relative humidity ; a significant diurnal temperature variation ; and extremely high levels of potential evaporation which are
12928-401: The polar front, although very attenuated by the rain shadow effects of the mountains and the annual average rainfall ranges from 100 millimetres (4 in) to 250 millimetres (10 in). For example, Biskra , Algeria, and Ouarzazate , Morocco, are found in this zone. The southern fringe of the desert along the border with the Sahel receives summer cloudiness and rainfall due to the arrival of
13056-400: The population has been affected by five or more floods in the 17 Sahel region countries. In 2012, severe drought conditions in the Sahel were reported. Governments in the region responded quickly, launching strategies to address the issue. The region is projected to experience changes in rainfall regime, with climate models suggesting that decreases in wet season rainfall are more likely in
13184-532: The recent past. Analysis of Nile River deposited sediments in the delta also shows this period had a higher proportion of sediments coming from the Blue Nile , suggesting higher rainfall also in the Ethiopian Highlands . This was caused principally by a stronger monsoonal circulation throughout the sub-tropical regions, affecting India, Arabia and the Sahara. Lake Victoria only recently became
13312-521: The region's wildlife populations, there are still some protected nature reserves within the region. Some of these include: West Africa is also home to several baobab trees and other plant life . Some baobab trees are several centuries old and form part of the local folklore, for example, a mythical baobab tree named Ngoye njuli in Senegal which is regarded as a sacred site by the Serer . The tree itself
13440-461: The regional and global economies. West Africa has a rich ecology , with strong biodiversity and several distinct regions. The area's climate and ecology are heavily influenced by the dry Sahara to the north and east, which provides dry winds during the Harmattan , as well as the Atlantic Ocean to the south and west, which provides seasonal monsoons. This mixture of climates gives West Africa
13568-453: The rest is "heavily fragmented and in a degraded state, being poorly used." Overfishing is a major issue in West Africa. Besides reducing fish stocks in the region, it also threatens food security and the livelihoods of many coastal communities that largely depend on artisanal fishing . The overfishing generally comes from foreign trawlers operating in the region. To combat the overfishing, Greenpeace has recommended countries reduce
13696-449: The road: The capitals' airports include: Of the sixteen, the most important hub and entry point to West Africa are Kotoka International Airport , and Murtala Muhammed International Airport , offering many international connections. Sahara The Sahara ( / s ə ˈ h ɑːr ə / , / s ə ˈ h ær ə / ) is a desert spanning across North Africa . With an area of 9,200,000 square kilometres (3,600,000 sq mi), it
13824-608: The same area suggest that they lived on the shores of a lake that was present during the Holocene Wet Phase, a period when the Sahara was verdant and wet. The Kiffian people were tall, standing over six feet in height. Craniometric analysis indicates that this early Holocene population was closely related to the Late Pleistocene Iberomaurusians and early Holocene Capsians of the Maghreb, as well as mid-Holocene Mechta groups. Traces of
13952-672: The same regions (e.g., Djado , Acacus , Tadrart ). Hunters in the Central Sahara farmed, stored, and cooked undomesticated central Saharan flora , underwent domestication of antelope , and domesticated and shepherded Barbary sheep . After the Kel Essuf Period and Round Head Period of the Central Sahara, the Pastoral Period followed. Some of the hunter-gatherers who created the Round Head rock art may have adopted pastoral culture, and others may have not. As
14080-463: The scale of the Nile floods between 2700 and 2100 BCE. The Sahara comprises several distinct ecoregions . With their variations in temperature, rainfall, elevation, and soil, these regions harbor distinct communities of plants and animals. The flora of the Sahara is highly diversified based on the bio-geographical characteristics of this vast desert. Floristically , the Sahara has three zones based on
14208-521: The shelter of shrubs such as balanites and acacias. They are unusually pale. The other cheetah subspecies ( northeast African cheetah ) lives in Chad, Sudan and the eastern region of Niger. However, it is currently extinct in the wild in Egypt and Libya. There are approximately 2000 mature individuals left in the wild. Other animals include the monitor lizards , hyrax , sand vipers , and small populations of African wild dog , in perhaps only 14 countries and red-necked ostrich . Other animals exist in
14336-647: The source of the White Nile and dried out almost completely around 15 kya. The sudden subsequent movement of the ITCZ southwards with a Heinrich event (a sudden cooling followed by a slower warming), linked to changes with the El Niño-Southern Oscillation cycle, led to a rapid drying out of the Saharan and Arabian regions, which quickly became desert. This is linked to a marked decline in
14464-646: The south Atlantic Ocean . In the United Nations scheme of African regions , the region of Western Africa includes 16 states and the United Kingdom Overseas Territory of Saint Helena, Ascension and Tristan da Cunha : Mali , Burkina Faso , Senegal and the Niger are mostly in the Sahel , a transition zone between the Sahara desert and the Sudanian Savanna ; Benin , Ivory Coast , The Gambia , Ghana , Guinea , Guinea-Bissau , Liberia , Sierra Leone , Togo and Nigeria compose most of Guinea ,
14592-561: The strongest anticyclonic weather regime, and the annual average rainfall can drop to less than 1 millimetre (0.04 in). In fact, most of the Sahara receives less than 20 millimetres (0.8 in). Of the 9,000,000 square kilometres (3,500,000 sq mi) of desert land in the Sahara, an area of about 2,800,000 square kilometres (1,100,000 sq mi) (about 31% of the total area) receives an annual average rainfall amount of 10 millimetres (0.4 in) or less, while some 1,500,000 square kilometres (580,000 sq mi) (about 17% of
14720-538: The subsequent expansion of the West African forest . West African hunter-gatherers occupied western Central Africa (e.g., Shum Laka ) earlier than 32,000 BP, dwelled throughout coastal West Africa by 12,000 BP, and migrated northward between 12,000 BP and 8000 BP as far as Mali, Burkina Faso, and Mauritania. During the Holocene , Niger-Congo speakers independently created pottery in Ounjougou , Mali –
14848-562: The theoretical maximum value. A value of 4300 hours (98%) of the time would be recorded in Upper Egypt ( Aswan , Luxor ) and in the Nubian Desert ( Wadi Halfa ). The annual average direct solar irradiation is around 2,800 kWh/(m year) in the Great Desert. The Sahara has a huge potential for solar energy production. The high position of the Sun, the extremely low relative humidity, and the lack of vegetation and rainfall make
14976-472: The tilt of the earth changes between 22° and 24.5°. At present, it is in a dry period, but it is expected that the Sahara will become green again in 15,000 years. When the North African monsoon is at its strongest, annual precipitation and subsequent vegetation in the Sahara region increase, resulting in conditions commonly referred to as the " green Sahara ". For a relatively weak North African monsoon,
15104-478: The total area) receives an average of 5 millimetres (0.2 in) or less. The annual average rainfall is virtually zero over a wide area of some 1,000,000 square kilometres (390,000 sq mi) in the eastern Sahara comprising deserts of: Libya, Egypt and Sudan ( Tazirbu , Kufra , Dakhla , Kharga , Farafra , Siwa , Asyut , Sohag , Luxor, Aswan, Abu Simbel , Wadi Halfa) where the long-term mean approximates 0.5 millimetres (0.02 in) per year. Rainfall
15232-661: The traditional name for the area near the Gulf of Guinea ; Mauritania lies in the Maghreb , the northwestern region of Africa that has historically been inhabited by West African groups such as the Fulani , Soninke , Wolof , Serer and Toucouleur people , along with Arab-Berber Maghrebi people such as the Tuareg ; Cape Verde is an island country in the Atlantic Ocean ; and Saint Helena, Ascension and Tristan da Cunha consists of eight main islands located in four different parts of
15360-470: The western Maghreb) is composed of semi-arid terrain known as Sahel , a transitional zone between the Sahara and the West Sudanian savanna . Forests form a belt between the savannas and the southern coast, ranging from 160 km to 240 km in width. The northwest African region of Mauritania periodically suffers country-wide plagues of locusts which consume water, salt and crops on which
15488-545: The western Sahel, and increases more likely in the central to east Sahel, although opposite trends cannot yet be ruled out. These trends will affect the frequency and severity of floods, droughts, desertification , sand and dust storms, desert locust plagues and water shortages. However, irrespective of the changes in seasonal mean rain, the most intense storms are expected to become more intense, amplifying flood frequency. Enhanced carbon emissions and global warming may also lead to an increase in dry spells especially across
15616-517: Was a Yoruba empire of what is today Western, North Central Nigeria and Southern Republic of Benin . Established in the 14th century, the Oyo Empire grew to become one of the largest West African states. It rose through the outstanding organizational skills of the Yoruba, wealth gained from trade and its powerful cavalry . The Oyo Empire was the most politically important state in the region from
15744-656: Was an embayment sloping down from the West African craton into the Tethys Ocean . It became a closed basin in the Late Carboniferous (320 Ma to 300 Ma). The basin has a steep northern edge against the Anti Atlas and more gently sloping southern edge. The basin is filled with up to 8 kilometres (5.0 mi) of sediment from the Cambrian and Carboniferous ageas. These marine formations are overlain by
15872-403: Was initially counteracted by the monsoon , which brought rain further north than it does today. By around 4200 BCE, however, the monsoon retreated south to approximately where it is today, leading to the gradual desertification of the Sahara. The Sahara is now as dry as it was about 13,000 years ago. Lake Chad is the remnant of a former inland sea, paleolake Mega-Chad, which existed during
16000-470: Was just one tenth the rainfall around 125 kya. In the southern Negev Desert speleothems did not grow between 185 and 140 kya ( MIS 6), 110–90 (MIS 5.4–5.2), nor after 85 kya nor during most of the interglacial period (MIS 5.1), the glacial period and Holocene . This suggests that the southern Negev was arid-to-hyper-arid in these periods. During the Last Glacial Maximum (LGM) the Sahara
16128-499: Was left of the local wildlife, but by that time, it was too late. During the 1930s, the elephant population in the Gold Coast was about 300, and Sierra Leone between 500 and 600. Although a small number of elephants survived in Nigeria, hunting, agricultural expansion and clearing of forest in that country drastically affected its wildlife population, particularly elephants. Despite the historical damage that has been done to
16256-489: Was more extensive than it is now with the extent of the tropical forests being greatly reduced, and the lower temperatures reduced the strength of the Hadley Cell . This is a climate cell which causes rising tropical air of the Inter-Tropical Convergence Zone (ITCZ) to bring rain to the tropics, while dry descending air, at about 20 degrees north , flows back to the equator and brings desert conditions to this region. It
16384-625: Was then succeeded by the Ghana Empire that first flourished roughly between the 2nd and 12th centuries C.E., which later gave way to the Mali Empire . In current-day Mauritania, there exist archaeological sites in the towns of Tichit and Oualata that were initially constructed around 2000 B.C., and were found to have originated from the Soninke branch of the Mandé peoples . Also, based on
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