, photo = Sahara real color.jpg
, photo_caption = The Sahara taken by
Apollo 17
Apollo 17 (December 7–19, 1972) was the final mission of NASA's Apollo program, the most recent time humans have set foot on the Moon or traveled beyond low Earth orbit. Commander Gene Cernan and Lunar Module Pilot Harrison Schmitt walked on ...
astronauts, 1972
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disputed
Controversy is a state of prolonged public dispute or debate, usually concerning a matter of conflicting opinion or point of view. The word was coined from the Latin ''controversia'', as a composite of ''controversus'' – "turned in an opposite d ...
)
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The Sahara (, ) is a
desert
A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...
on the
African continent
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
. With an area of , it is the largest hot desert in the world and the
third-largest desert overall, smaller only than the deserts of
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
and the northern
Arctic
The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
.
The name "Sahara" is derived from the Arabic word for "desert" in the feminine irregular form, the singular ( ), plural ( ), (), (), ().
The desert comprises much of
North Africa
North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...
, excluding the fertile region on the
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...
coast, the
Atlas Mountains
The Atlas Mountains are a mountain range in the Maghreb in North Africa. It separates the Sahara Desert from the Mediterranean Sea and the Atlantic Ocean; the name "Atlantic" is derived from the mountain range. It stretches around through Moroc ...
of the
Maghreb
The Maghreb (; ar, الْمَغْرِب, al-Maghrib, lit=the west), also known as the Arab Maghreb ( ar, المغرب العربي) and Northwest Africa, is the western part of North Africa and the Arab world. The region includes Algeria, ...
, and the
Nile Valley
The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest rive ...
in
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
and the
Sudan
Sudan ( or ; ar, السودان, as-Sūdān, officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is a country in Northeast Africa. It shares borders with the Central African Republic t ...
. It stretches from the
Red Sea
The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...
in the east and the Mediterranean in the north to the
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
in the west, where the landscape gradually changes from desert to coastal plains. To the south it is bounded by the
Sahel
The Sahel (; ar, ساحل ' , "coast, shore") is a region in North Africa. It is defined as the ecoclimatic and biogeographic realm of transition between the Sahara to the north and the Sudanian savanna to the south. Having a hot semi-arid c ...
, a belt of
semi-arid tropical savanna around the
Niger River
The Niger River ( ; ) is the main river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through ...
valley and the
Sudan region
Sudan is the geographical region to the south of the Sahara, stretching from Western Africa to Central and Eastern Africa. The name derives from the Arabic ' (), or "the lands of the Blacks", referring to West Africa and northern Central Afric ...
of
sub-Saharan Africa
Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...
. The Sahara can be divided into several regions, including the western Sahara, the central
Ahaggar Mountains
The Hoggar Mountains ( ar, جبال هقار, Berber: ''idurar n Ahaggar'') are a highland region in the central Sahara in southern Algeria, along the Tropic of Cancer. The mountains cover an area of approximately 550,000 km.
Geography
Thi ...
, the
Tibesti Mountains
The Tibesti Mountains are a mountain range in the central Sahara, primarily located in the extreme north of Chad, with a small portion located in southern Libya. The highest peak in the range, Emi Koussi, lies to the south at a height of and i ...
, the
Aïr Mountains
The Aïr Mountains or Aïr Massif ( tmh, Ayăr; Hausa: Eastern ''Azbin'', Western ''Abzin'') is a triangular massif, located in northern Niger, within the Sahara. Part of the West Saharan montane xeric woodlands ecoregion, they r ...
, the
Ténéré
The Ténéré (Tuareg: Tenere, literally: "desert") is a desert region in the south central Sahara. It comprises a vast plain of sand stretching from northeastern Niger into western Chad, occupying an area of over . The Ténéré's boundaries are ...
desert, and the
Libyan Desert
The Libyan Desert (not to be confused with the Libyan Sahara) is a geographical region filling the north-eastern Sahara Desert, from eastern Libya to the Western Desert of Egypt and far northwestern Sudan. On medieval maps, its use predates t ...
.
For several hundred thousand years, the Sahara has alternated between desert and savanna grassland in a 20,000-year cycle caused by the
precession
Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In othe ...
of Earth's
axis
An axis (plural ''axes'') is an imaginary line around which an object rotates or is symmetrical. Axis may also refer to:
Mathematics
* Axis of rotation: see rotation around a fixed axis
*Axis (mathematics), a designator for a Cartesian-coordinate ...
as it rotates around the Sun, which changes the location of the
North African monsoon North African climate cycles have a unique history that can be traced back millions of years. The cyclic climate pattern of the Sahara is characterized by significant shifts in the strength of the North African Monsoon. When the North African Monsoo ...
.
Geography
![Sahara satellite hires](https://upload.wikimedia.org/wikipedia/commons/a/a7/Sahara_satellite_hires.jpg)
The Sahara covers large parts of
Algeria
)
, image_map = Algeria (centered orthographic projection).svg
, map_caption =
, image_map2 =
, capital = Algiers
, coordinates =
, largest_city = capital
, relig ...
,
Chad
Chad (; ar, تشاد , ; french: Tchad, ), officially the Republic of Chad, '; ) is a landlocked country at the crossroads of North and Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic ...
,
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
,
Libya
Libya (; ar, ليبيا, Lībiyā), officially the State of Libya ( ar, دولة ليبيا, Dawlat Lībiyā), is a country in the Maghreb region in North Africa. It is bordered by the Mediterranean Sea to the north, Egypt to Egypt–Libya bo ...
,
Mali
Mali (; ), officially the Republic of Mali,, , ff, 𞤈𞤫𞤲𞥆𞤣𞤢𞥄𞤲𞤣𞤭 𞤃𞤢𞥄𞤤𞤭, Renndaandi Maali, italics=no, ar, جمهورية مالي, Jumhūriyyāt Mālī is a landlocked country in West Africa. Mali ...
,
Mauritania
Mauritania (; ar, موريتانيا, ', french: Mauritanie; Berber: ''Agawej'' or ''Cengit''; Pulaar: ''Moritani''; Wolof: ''Gànnaar''; Soninke:), officially the Islamic Republic of Mauritania ( ar, الجمهورية الإسلامية ...
,
Morocco
Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...
,
Niger
)
, official_languages =
, languages_type = National languages[Western Sahara
Western Sahara ( '; ; ) is a disputed territory on the northwest coast and in the Maghreb region of North and West Africa. About 20% of the territory is controlled by the self-proclaimed Sahrawi Arab Democratic Republic (SADR), while the r ...](_blank)
,
Sudan
Sudan ( or ; ar, السودان, as-Sūdān, officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is a country in Northeast Africa. It shares borders with the Central African Republic t ...
and
Tunisia
)
, image_map = Tunisia location (orthographic projection).svg
, map_caption = Location of Tunisia in northern Africa
, image_map2 =
, capital = Tunis
, largest_city = capital
, ...
. It covers , amounting to 31% of Africa. If all areas with a mean annual precipitation of less than 250 mm were included, the Sahara would be . It is one of three distinct
physiographic provinces
physiographic province is a geographic region with a characteristic geomorphology, and often specific subsurface rock type or structural elements. The continents are subdivided into various physiographic provinces, each having a specific charact ...
of the
African massive physiographic division. Sahara is so large and bright that, in theory, it could be detected from other stars as a surface feature of Earth, with near-current technology.
The Sahara is mainly rocky
hamada
A hamada ( ar, حمادة, ) is a type of desert landscape consisting of high, largely barren, hard rocky plateaus, where most of the sand has been removed by deflation. The majority of the Sahara is in fact hamada. Other examples are Negev dese ...
(stone plateaus);
ergs
The erg is a unit of energy equal to 10−7joules (100 nJ). It originated in the Centimetre–gram–second system of units (CGS). It has the symbol ''erg''. The erg is not an SI unit. Its name is derived from (), a Greek word meaning 'work' o ...
(sand seas – large areas covered with sand
dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, f ...
s) form only a minor part, but many of the
sand dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, fl ...
s are over high.
Wind
Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hou ...
or rare rainfall shape the desert features: sand dunes, dune fields, sand seas, stone plateaus, gravel plains (''reg''),
dry valleys
The McMurdo Dry Valleys are a row of largely snow-free valleys in Antarctica, located within Victoria Land west of McMurdo Sound. The Dry Valleys experience extremely low humidity and surrounding mountains prevent the flow of ice from nearby ...
(''wadi''),
dry lake
A dry lake bed, also known as a playa, is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceeds recharge. If the floor of a dry lake is covered by deposits of alkaline c ...
s (''oued''), and
salt flats Salt flats, Salt flat, Salt Flats, or Salt Flat may refer to: Geology
*Salt pan (geology), a flat expanse of ground covered with salt and other minerals
* Dry lake, an ephemeral lakebed that consists of fine-grained sediments infused with alkali sal ...
(''shatt'' or ''chott'').
Unusual landforms include the
Richat Structure
The Richat Structure, also called ''Guelb er Richât'' ( ar, قلب الريشات, Qalb ar-Rīšāt), is a prominent circular geological feature in the Sahara's Adrar Plateau, near Ouadane, west–central Mauritania, Northwest Africa. In t ...
in Mauritania.
Several deeply dissected mountains, many volcanic, rise from the desert, including the
Aïr Mountains
The Aïr Mountains or Aïr Massif ( tmh, Ayăr; Hausa: Eastern ''Azbin'', Western ''Abzin'') is a triangular massif, located in northern Niger, within the Sahara. Part of the West Saharan montane xeric woodlands ecoregion, they r ...
,
Ahaggar Mountains
The Hoggar Mountains ( ar, جبال هقار, Berber: ''idurar n Ahaggar'') are a highland region in the central Sahara in southern Algeria, along the Tropic of Cancer. The mountains cover an area of approximately 550,000 km.
Geography
Thi ...
,
Saharan Atlas Saharan may refer to:
* Someone or something from the Sahara desert
* Sahrawi people (also spelled Saharawi), the indigenous people of Western Sahara
* Saharan languages
The Saharan languages are a small family of languages across parts of the ea ...
,
Tibesti Mountains
The Tibesti Mountains are a mountain range in the central Sahara, primarily located in the extreme north of Chad, with a small portion located in southern Libya. The highest peak in the range, Emi Koussi, lies to the south at a height of and i ...
,
Adrar des Iforas
The Adrar des Ifoghas (also Adrar des Iforas; Tamasheq: ⴰⴷⵔⴰⵔ ⵏ ⵉⴼⵓⵖⴰⵙ in Tifinagh; Adrar n Ifoghas; ar, أدرار إيفوغاس Ifoghas' Mountains) is a massif located in the Kidal Region of Mali, reaching into Algeri ...
, and the
Red Sea Hills
Itbāy ( ar, اطبيه) or ʿAtbāy is a region of southeastern Egypt and northeastern Sudan. It is characterized by a chain of mountains, the Red Sea Hills, running north–south and parallel with the Red Sea. The hills separate the narrow coas ...
. The highest peak in the Sahara is
Emi Koussi
Emi Koussi (also known as Emi Koussou) is a high pyroclastic shield volcano that lies at the southeast end of the Tibesti Mountains in the central Sahara, in the northern Borkou Region of northern Chad. The highest mountain of the Sahara, the vo ...
, a
shield volcano
A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more v ...
in the
Tibesti
The Tibesti Mountains are a mountain range in the central Sahara, primarily located in the extreme north of Chad, with a small portion located in southern Libya. The highest peak in the range, Emi Koussi, lies to the south at a height of and is ...
range of northern Chad.
The central Sahara is
hyperarid
An aridity index (AI) is a numerical indicator of the degree of dryness of the climate at a given location. A number of aridity indices have been proposed (see below); these indicators serve to identify, locate or delimit regions that suffer from ...
, with sparse vegetation. The northern and southern reaches of the desert, along with the highlands, have areas of sparse grassland and
desert shrub
Deserts and xeric shrublands are a biome defined by the World Wide Fund for Nature. Deserts and xeric (ancient Greek xērós, “dry") shrublands form the largest terrestrial biome, covering 19% of Earth's land surface area. Ecoregions in this ...
, with trees and taller shrubs in
wadi
Wadi ( ar, وَادِي, wādī), alternatively ''wād'' ( ar, وَاد), North African Arabic Oued, is the Arabic term traditionally referring to a valley. In some instances, it may refer to a wet (ephemeral) riverbed that contains water onl ...
s, where moisture collects. In the central, hyperarid region, there are many subdivisions of the great desert:
Tanezrouft
The Tanezrouft ( ar, تنزروفت) is a natural region located along the borders of Algeria and Mali, west of the Hoggar Mountains. Along with the Libyan Desert it is one of the most desolate and most arid parts of the Sahara Desert. This area ha ...
, the
Ténéré
The Ténéré (Tuareg: Tenere, literally: "desert") is a desert region in the south central Sahara. It comprises a vast plain of sand stretching from northeastern Niger into western Chad, occupying an area of over . The Ténéré's boundaries are ...
, the
Libyan Desert
The Libyan Desert (not to be confused with the Libyan Sahara) is a geographical region filling the north-eastern Sahara Desert, from eastern Libya to the Western Desert of Egypt and far northwestern Sudan. On medieval maps, its use predates t ...
, the
Eastern Desert
The Eastern Desert (Archaically known as Arabia or the Arabian Desert) is the part of the Sahara desert that is located east of the Nile river. It spans of North-Eastern Africa and is bordered by the Nile river to the west and the Red Sea and ...
, the
Nubian Desert
The Nubian Desert ( ar, صحراء النوبة, ''Şaḩrā’ an Nūbyah'') is in the eastern region of the Sahara Desert, spanning approximately 400,000 km2 of northeastern Sudan and northern Eritrea, between the Nile and the Red Sea. Th ...
and others. These extremely arid areas often receive no rain for years.
To the north, the Sahara skirts the
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...
in Egypt and portions of Libya, but in
Cyrenaica
Cyrenaica ( ) or Kyrenaika ( ar, برقة, Barqah, grc-koi, Κυρηναϊκή παρχίαKurēnaïkḗ parkhíā}, after the city of Cyrene), is the eastern region of Libya. Cyrenaica includes all of the eastern part of Libya between ...
and the
Maghreb
The Maghreb (; ar, الْمَغْرِب, al-Maghrib, lit=the west), also known as the Arab Maghreb ( ar, المغرب العربي) and Northwest Africa, is the western part of North Africa and the Arab world. The region includes Algeria, ...
, the Sahara borders the
Mediterranean forest, woodland, and scrub
Mediterranean forests, woodlands, and scrub is a biome defined by the World Wide Fund for Nature. The biome is generally characterized by dry summers and rainy winters, although in some areas rainfall may be uniform. Summers are typically hot in ...
eco-regions of northern Africa, all of which have a
Mediterranean climate
A Mediterranean climate (also called a dry summer temperate climate ''Cs'') is a temperate climate sub-type, generally characterized by warm, dry summers and mild, fairly wet winters; these weather conditions are typically experienced in the ...
characterized by hot summers and cool and rainy winters. According to the botanical criteria of
Frank White and geographer Robert Capot-Rey,
the northern limit of the Sahara corresponds to the northern limit of
date palm
''Phoenix dactylifera'', commonly known as date or date palm, is a flowering plant species in the palm family, Arecaceae, cultivated for its edible sweet fruit called dates. The species is widely cultivated across northern Africa, the Middle Eas ...
cultivation and the southern limit of the range of
esparto
Esparto, halfah grass, or esparto grass is a fiber produced from two species of perennial grasses of north Africa, Spain and Portugal. It is used for crafts, such as cords, basketry, and espadrilles. ''Stipa tenacissima'' and ''Lygeum spartum ...
, a
grass
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...
typical of the Mediterranean climate portion of the Maghreb and
Iberia
The Iberian Peninsula (),
**
* Aragonese and Occitan: ''Peninsula Iberica''
**
**
* french: Péninsule Ibérique
* mwl, Península Eibérica
* eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...
. The northern limit also corresponds to the
isohyet
A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional graph ...
of annual precipitation.
To the south, the Sahara is bounded by the Sahel, a belt of dry
tropical savanna
Tropical and subtropical grasslands, savannas, and shrublands is a terrestrial biome defined by the World Wide Fund for Nature. The biome is dominated by grass and/or shrubs located in semi-arid to semi-humid climate regions of subtropical and t ...
with 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
''Cornulaca monacantha'' is a species of flowering plant in the genus '' Cornulaca'', that is now included in the family Amaranthaceae, (formerly Chenopodiaceae). It is a desert plant found in the Middle East and the Sahara, and the southern e ...
'' (a drought-tolerant member of the
Chenopodiaceae
Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus ''Amaranthus''. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it ...
), or northern limit of ''
Cenchrus biflorus
''Cenchrus biflorus'' is a species of annual grass in the family Poaceae. Common names include Indian sandbur, ''Bhurat'' or ''Bhurut'' in India, ''Haskaneet'' in Sudan, ''Aneeti'' in the Arabic dialect of Mauritania, ''K 'arangiya'' in the ...
'', a
grass
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...
typical of the Sahel.
According to climatic criteria, the southern limit of the Sahara corresponds to the isohyet of annual precipitation (this is a long-term average, since
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
varies annually).
Important cities located in the Sahara include
Nouakchott
, image_skyline = Nouakchott.jpg
, image_caption = City view of Nouakchott
, pushpin_map = Mauritania#Arab world#Africa
, pushpin_relief = 1
, mapsize =
, map_caption ...
, the capital of Mauritania;
Tamanrasset
Tamanrasset (; ar, تامنراست), also known as Tamanghasset or Tamenghest, is an oasis city and capital of Tamanrasset Province in southern Algeria, in the Ahaggar Mountains. It is the chief city of the Algerian Tuareg. It is located an alt ...
,
Ouargla
Ouargla ( Berber: Wargrən, ar, ورقلة) is the capital city of Ouargla Province in the Sahara Desert in southern Algeria. It has a flourishing petroleum industry and hosts one of Algeria's universities, the University of Ouargla. The commune ...
,
Béchar
Béchar ( ar, بشار) is the capital city of Béchar Province, Algeria. It is also a commune, coextensive with Béchar District, of Béchar Province. In 2008 the city had a population of 165,627, up from 134,954 in 1998, with an annual growth ...
,
Hassi Messaoud
Hassi Messaoud ( ar, حاسي مسعود) is a town in Ouargla Province, eastern Algeria, located southeast of Ouargla. As of 2008 it had a population of 45,147 people, up from 40,360 in 1998, and an annual population growth rate of 1.1%, the lowe ...
,
Ghardaïa
Ghardaïa ( ar, غرداية, Mzab-Berber: ''Taɣerdayt'') is the capital city of Ghardaïa Province, Algeria. The commune of Ghardaïa has a population of 93,423 according to the 2008 census, up from 87,599 in 1998, with an annual growth rate ...
, and
El Oued
El Oued ( ar, اﻟﻮادي, ber, Suf meaning ''the River''), Souf or Oued Souf is a city, and the capital of El Oued Province, in Algeria. The oasis town is watered by an underground river, hence its name is El Oued which enables date palm cult ...
in Algeria;
Timbuktu
Timbuktu ( ; french: Tombouctou;
Koyra Chiini: ); tmh, label=Tuareg, script=Tfng, ⵜⵏⴱⴾⵜ, Tin Buqt a city in Mali, situated north of the Niger River. The town is the capital of the Tombouctou Region, one of the eight administrativ ...
in Mali;
Agadez
Agadez ( Air Tamajeq: ⴰⴶⴰⴷⴰⵣ, ''Agadaz''), formerly spelled Agadès, is the fifth largest city in Niger, with a population of 110,497 based on the 2012 census. The capital of Agadez Region, it lies in the Sahara desert, and is also ...
in Niger;
Ghat
Ghat, a term used in the Indian subcontinent, depending on the context could refer either to a range of stepped hills with valleys (ghati in Hindi), such as the Eastern Ghats and Western Ghats; or the series of steps leading down to a body of ...
in Libya; and
Faya-Largeau
Faya-Largeau (also known as Faya, ar, فايا لارجو or ) is the largest city in northern Chad and was the capital of the region of Bourkou-Ennedi-Tibesti. It is now in the Borkou Region, which was formed in 2008 from the Borkou Departmen ...
in Chad.
Climate
![Hoggar8](https://upload.wikimedia.org/wikipedia/commons/1/17/Hoggar8.jpg)
The Sahara is the world's largest
hot desert
A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one ...
. It is located in the
horse latitudes
The horse latitudes are the latitudes about 30 degrees north and south of the Equator. They are characterized by sunny skies, calm winds, and very little precipitation. They are also known as subtropical ridges, or highs. It is a high-pressure ...
under the
subtropical ridge
The horse latitudes are the latitudes about 30 degrees north and south of the Equator. They are characterized by sunny skies, calm winds, and very little precipitation. They are also known as Subtropics, subtropical ridges, or highs. It is a h ...
, 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 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 system
A high-pressure area, high, or anticyclone, is an area near the surface of a planet where the atmospheric pressure is greater than the pressure in the surrounding regions. Highs are middle-scale meteorological features that result from interpl ...
s are extremely unfavorable for the development of convectional showers. The subtropical ridge is the predominant factor that explains the
hot desert climate
The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a dry climate sub-type in which there is a severe excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in desert ...
(
Köppen climate classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notabl ...
''BWh'') of this vast region. The descending airflow 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
The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in the ...
, lying in
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
and
Peru
, image_flag = Flag of Peru.svg
, image_coat = Escudo nacional del Perú.svg
, other_symbol = Great Seal of the State
, other_symbol_type = Seal (emblem), National seal
, national_motto = "Fi ...
.
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
In meteorology, an air mass is a volume of air defined by its temperature and humidity. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to la ...
lying above 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
Thermal lows, or heat lows, are non-frontal low-pressure areas that occur over the continents in the subtropics during the warm season, as the result of intense heating when compared to their surrounding environments.Glossary of Meteorology (200 ...
is usually noticed near the surface, and is the strongest and the most developed during the summertime. The
Sahara High
, photo = Sahara real color.jpg
, photo_caption = The Sahara taken by Apollo 17 astronauts, 1972
, map =
, map_image =
, location =
, country =
, country1 =
, ...
represents the eastern continental extension of the
Azores High
The Azores High also known as North Atlantic (Subtropical) High/Anticyclone or the Bermuda-Azores High, is a large subtropical semi-permanent centre of high atmospheric pressure typically found south of the Azores in the Atlantic Ocean, at the Hor ...
, centered over the
North Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe an ...
. 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 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
The Atlas Mountains are a mountain range in the Maghreb in North Africa. It separates the Sahara Desert from the Mediterranean Sea and the Atlantic Ocean; the name "Atlantic" is derived from the mountain range. It stretches around through Moroc ...
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
A rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds, known as its leeward side.
Evaporated moisture from water bodies (such as oceans and large lakes) is carrie ...
effect on the leeward side by dropping much of the humidity brought by atmospheric disturbances along the
polar front
In meteorology, the polar front is the weather front boundary between the polar cell and the Ferrel cell around the 60° latitude, near the polar regions, in both hemisphere. At this boundary a sharp gradient in temperature occurs between these ...
which affects the surrounding Mediterranean climates.
The primary source of rain in the Sahara is the
Intertropical Convergence Zone
The Intertropical Convergence Zone (ITCZ ), known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal e ...
, a continuous belt of low-pressure systems near the equator which bring the brief, short and irregular
rainy season
The rainy season is the time of year when most of a region's average annual rainfall occurs.
Rainy Season may also refer to:
* ''Rainy Season'' (short story), a 1989 short horror story by Stephen King
* "Rainy Season", a 2018 song by Monni
* ''T ...
to the
Sahel
The Sahel (; ar, ساحل ' , "coast, shore") is a region in North Africa. It is defined as the ecoclimatic and biogeographic realm of transition between the Sahara to the north and the Sudanian savanna to the south. Having a hot semi-arid c ...
and southern Sahara. Rainfall in this giant desert has to overcome 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
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present.
Humidity depe ...
; a significant
diurnal temperature variation
In meteorology, diurnal temperature variation is the variation between a high air temperature and a low temperature that occurs during the same day.
Temperature lag
Temperature lag is an important factor in diurnal temperature variation: peak d ...
; and extremely high levels of
potential evaporation
Potential evaporation (PE) or potential evapotranspiration (PET) is defined as the amount of evaporation that would occur if a sufficient water source were available. If the actual evapotranspiration is considered the net result of atmospheric d ...
which are the highest recorded worldwide.
Temperature
The sky is usually clear above the desert, and the
sunshine duration
Sunshine duration or sunshine hours is a climatological indicator, measuring duration of sunshine in given period (usually, a day or a year) for a given location on Earth, typically expressed as an averaged value over several years. It is a gene ...
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 the theoretical maximum value. A value of 4300 hours (98%) of the time would be recorded in
Upper Egypt
Upper Egypt ( ar, صعيد مصر ', shortened to , , locally: ; ) is the southern portion of Egypt and is composed of the lands on both sides of the Nile that extend upriver from Lower Egypt in the north to Nubia in the south.
In ancient ...
(
Aswan
Aswan (, also ; ar, أسوان, ʾAswān ; cop, Ⲥⲟⲩⲁⲛ ) is a city in Southern Egypt, and is the capital of the Aswan Governorate.
Aswan is a busy market and tourist centre located just north of the Aswan Dam on the east bank of the ...
,
Luxor
Luxor ( ar, الأقصر, al-ʾuqṣur, lit=the palaces) is a modern city in Upper (southern) Egypt which includes the site of the Ancient Egyptian city of ''Thebes''.
Luxor has frequently been characterized as the "world's greatest open-a ...
) and in the Nubian Desert (
Wadi Halfa
Wādī Ḥalfā ( ar, وادي حلفا) is a city in the Northern state of Sudan on the shores of Lake Nubia near the border with Egypt. It is the terminus of a rail line from Khartoum and the point where goods are transferred from rail to ferr ...
).
The annual average
direct solar irradiation is around 2,800 kWh/(m
2 year) in the Great Desert. The Sahara has a huge potential for solar energy production.
![Algeria Sahara Desert Photo From Drone 5](https://upload.wikimedia.org/wikipedia/commons/a/a0/Algeria_Sahara_Desert_Photo_From_Drone_5.jpg)
The high position of the Sun, the extremely low relative humidity, and the lack of
vegetation
Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic character ...
and rainfall make 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 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 in a remote desert town in the
Algerian Desert
The Algerian Desert ( ar, الصحراء الجزائرية) is located in north-central Africa and is part of the Sahara Desert. The desert occupies more than four-fifths of Algerian territory. Its expansion starts from the Saharan Atlas as a ...
called
Bou Bernous
Bou Bernous is a village in the commune of Oum El Assel, in Tindouf Province, Algeria
)
, image_map = Algeria (centered orthographic projection).svg
, map_caption =
, image_map2 =
, capital ...
, at an elevation of above sea level,
and only
Death Valley, California
Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the Highest temperature recorded on Earth, hottest place on Earth.
Death Valley's Badwater Basin is the ...
rivals it. Other hot spots in Algeria such as
Adrar Adrar (in Tifinagh script "ⴰⴷⵔⴰⵔ"), a Berber word meaning "mountain", is the name of several areas in Northwest Africa:
Algeria
* Adrar, Algeria, a town in Algeria
* Adrar Province, an administrative division of Algeria
* Adrar District, ...
,
Timimoun
Timimoun ( ar, ﺗﻴﻤﻴﻤﻮن) is a town and commune, and capital of Timimoun District, in Adrar Province, south-central Algeria. According to the 2008 census it has a population of 33,060, up from 28,595 in 1998, with an annual growth rate ...
,
In Salah
In Salah or officially Aïn Salah ( ar, عين صالح) is the oasis town in central Algeria that is the capital of the In Salah Province and In Salah District. It was once an important trade link of the trans-Saharan caravan route. As of the 2 ...
,
Ouallene
Ouallene or Ouallen is a desert town and bordj in southern Algeria. The village is located in the Adrar Province to the southeast of Reggane. The bordj sits at an elevation of about 346 m (1,135 ft) above sea level and lies in the heart of ...
,
Aoulef
Aoulef ( ar, أولف , translit=Awlaf) is a town and commune and capital of Aoulef District, in Adrar Province, south-central Algeria. According to the 2008 census it has a population of 21,723, up from 15,229 in 1998, with an annual growth rate ...
,
Reggane
Reggane (from Berber "Argan"; ar, رقان) is a town and commune, and the capital of Reggane District, in Adrar Province, central Algeria. Reggane lies in the Sahara Desert near an oasis. According to the 2008 census it has a population of 20,40 ...
with an elevation between above sea level get slightly lower summer average highs, around during the hottest months of the year. Salah, well known in Algeria for its extreme heat, has average high temperatures of , , and 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
The Azalai (Tamasheq, var. Azalay) is a semi-annual salt caravan route practiced by Tuareg traders in the Sahara desert between Timbuktu and the Taoudenni salt mine in Mali, or the act of traveling with a caravan along that route.
The other maj ...
, lying in northern Mali. The major part of the desert experiences around three to five months when the average high strictly exceeds ; while in the southern central part of the desert, there are up to six or seven months when the average high temperature strictly exceeds . Some examples of this are
Bilma
Bilma is an oasis town and commune in north east Niger with, as of the 2012 census, a total population of 4,016 people.
It lies protected from the desert dunes under the Kaouar Cliffs and is the largest town along the Kaouar escarpment. It ...
, Niger and Faya-Largeau, Chad. The annual average daily temperature exceeds everywhere and can approach in the hottest regions year-round. However, most of the desert has a value in excess of .
![Sunset in Sahara](https://upload.wikimedia.org/wikipedia/commons/b/b5/Sunset_in_Sahara.jpg)
Sand and ground temperatures are even more extreme. During daytime, the sand temperature is extremely high: it can easily reach or more.
A sand temperature of 83.5 °C (182.3 °F) has been recorded in
Port Sudan
Port Sudan ( ar, بور سودان, Būr Sūdān) is a port city in eastern Sudan, and the capital of the state of Red Sea. , it has 489,725 residents. Located on the Red Sea, Port Sudan is recognized as Sudan's main seaport and the source of 90% ...
.
Ground temperatures of have been recorded in the
Adrar of Mauritania and a value of 75 °C (167 °F) has been measured in
Borkou
Borku (french: Borkou) or Borgu (') is a region of Central Africa, mostly in Northern Chad, forming part of the transitional zone between the arid wastes of the Sahara and the fertile lands of the central Sudan. It is bounded N. by the Tibesti ...
, northern Chad.
Due to lack of cloud cover and very low humidity, the desert usually has high
diurnal temperature variation
In meteorology, diurnal temperature variation is the variation between a high air temperature and a low temperature that occurs during the same day.
Temperature lag
Temperature lag is an important factor in diurnal temperature variation: peak d ...
s 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 cooler than in the daytime. The smallest variations are found along the coastal regions due to high humidity and are often even lower than a 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 the Sahara is strongly influenced by the
North Atlantic Oscillation
The North Atlantic Oscillation (NAO) is a weather phenomenon over the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level (SLP) between the Icelandic Low and the Azores High. Through fluctuations in the ...
(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 the flow of dry, cold air from higher latitudes of Eurasia into the Sahara significantly.
Precipitation
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 system
In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...
s over the Mediterranean Sea along the polar front, although very attenuated by the rain shadow effects of the mountains and the annual average rainfall ranges from to . For example,
Biskra
Biskra ( ar, بسكرة ; ; Latin Vescera) is the capital city of Biskra Province, Algeria. In 2007, its population was recorded as 307,987. Biskra is located in northeastern Algeria, about 248 miles (400 km) from Algiers, 71 miles (115&nbs ...
, Algeria, and
Ouarzazate
Ouarzazate (; ar, ورزازات, Warzāzāt, ; ary, وارزازات, Wārzāzāt; shi, label= Berber, ⵡⴰⵔⵣⴰⵣⴰⵜ, Warzazat), nicknamed ''the door of the desert'', is a city and capital of Ouarzazate Province in the region of Dr ...
, 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 the Intertropical Convergence Zone from the south and the annual average rainfall ranges from to . For example, Timbuktu, Mali and
Agadez
Agadez ( Air Tamajeq: ⴰⴶⴰⴷⴰⵣ, ''Agadaz''), formerly spelled Agadès, is the fifth largest city in Niger, with a population of 110,497 based on the 2012 census. The capital of Agadez Region, it lies in the Sahara desert, and is also ...
, 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 the strongest anticyclonic weather regime, and the annual average rainfall can drop to less than . In fact, most of the Sahara receives less than . Of the of desert land in the Sahara, an area of about (about 31% of the total area) receives an annual average rainfall amount of or less, while some (about 17% of the total area) receives an average of or less.
The annual average rainfall is virtually zero over a wide area of some in the eastern Sahara comprising deserts of: Libya, Egypt and Sudan (
Tazirbu
Tazerbu ( ar, تازربو) is an oasis located in the Libyan Desert in the Kufra District of Libya, about 250 km to the northwest of Kufra.Bertarelli (1929), p. 515. The name means "main seat" in the Toubou language, because this was the sea ...
,
Kufra
Kufra () is a basinBertarelli (1929), p. 514. and oasis group in the Kufra District of southeastern Cyrenaica in Libya. At the end of nineteenth century Kufra became the centre and holy place of the Senussi order. It also played a minor role in ...
,
Dakhla,
Kharga
The Kharga Oasis (Arabic: , ) ; Coptic: ( "Oasis of Hib", "Oasis of Psoi") is the southernmost of Egypt's five western oases. It is located in the Western Desert, about 200 km (125 miles) to the west of the Nile valley. "Kharga" or ...
,
Farafra
The Farafra depression ( ar, واحة الفرافرة, ) is a geological depression, the second biggest by size in Western Egypt and the smallest by population, near latitude 27.06° north and longitude 27.97° east. It is in the large Western ...
,
Siwa,
Asyut
AsyutAlso spelled ''Assiout'' or ''Assiut'' ( ar, أسيوط ' , from ' ) is the capital of the modern Asyut Governorate in Egypt. It was built close to the ancient city of the same name, which is situated nearby. The modern city is located at , ...
,
Sohag
Sohag ( , ), also spelled as ''Sawhāj'', ''Suhag'' and ''Suhaj'', is a city on the west bank of the Nile in Egypt. It has been the capital of Sohag Governorate since 1960, before which the capital was Girga and the name of the governorate was ...
, Luxor, Aswan,
Abu Simbel
Abu Simbel is a historic site comprising two massive rock-cut temples in the village of Abu Simbel ( ar, أبو سمبل), Aswan Governorate, Upper Egypt, near the border with Sudan. It is situated on the western bank of Lake Nasser, about sou ...
, Wadi Halfa) where the long-term mean approximates per year.
Rainfall 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 per year to more than per year in the whole desert. Nowhere else on Earth has air been found as dry and evaporative as in 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
Ain (, ; frp, En) is a department in the Auvergne-Rhône-Alpes region in Eastern France. Named after the Ain river, it is bordered by the Saône and Rhône rivers. Ain is located on the country's eastern edge, on the Swiss border, where it ...
.
Desertification and prehistoric climate
![Journal](https://upload.wikimedia.org/wikipedia/commons/5/54/Journal.pone.0076514.g004.png)
One theory for the formation of the Sahara is that the monsoon in Northern Africa was weakened because of glaciation during the
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
period, starting two or three million years ago. Another theory is that the monsoon was weakened when the ancient
Tethys Sea
The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents ...
dried up during the
Tortonian
The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian.
The Torton ...
period around 7 million years.
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 North African climate cycles have a unique history that can be traced back millions of years. The cyclic climate pattern of the Sahara is characterized by significant shifts in the strength of the North African Monsoon. When the North African Monso ...
that alters the path of the
North African Monsoon North African climate cycles have a unique history that can be traced back millions of years. The cyclic climate pattern of the Sahara is characterized by significant shifts in the strength of the North African Monsoon. When the North African Monsoo ...
– usually southward. The cycle is caused by a 41,000-year cycle in which the tilt of the earth changes between 22° and 24.5°.
At present (2000), we are 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
The African humid period (AHP) (also known by other names) is a climate period in Africa during the late Pleistocene and Holocene geologic epochs, when northern Africa was wetter than today. The covering of much of the Sahara desert by grasses, ...
". For a relatively weak North African monsoon, 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 irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument.
Solar irradiance is measured in watts per square metre (W/m ...
(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 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.
![Village Telly in Mali](https://upload.wikimedia.org/wikipedia/commons/2/29/Village_Telly_in_Mali.jpg)
During the last
glacial period
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...
, 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 area
In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...
s over the collapsing
ice sheet
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Las ...
s to the north. Once the ice sheets were gone, the northern Sahara dried out. In the southern Sahara, the drying trend was initially counteracted by the
monsoon
A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscil ...
, which brought rain further north than it does today. By around 4200 BCE, however, the monsoon retreated south to approximately where it is today,
[Sahara's Abrupt Desertification Started by Changes in Earth's Orbit](_blank)
Accelerated by Atmospheric and Vegetation Feedbacks. leading to the gradual
desertification
Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid. It is the spread of arid areas caused by ...
of the Sahara. The Sahara is now as dry as it was about 13,000 years ago.
[
]Lake Chad
Lake Chad (french: Lac Tchad) is a historically large, shallow, endorheic lake in Central Africa, which has varied in size over the centuries. According to the ''Global Resource Information Database'' of the United Nations Environment Programme, ...
is the remnant of a former inland sea, paleolake Mega-Chad, which existed during 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 km2.
The Sahara pump theory
The Sahara pump theory is a hypothesis that explains how flora and fauna migrated between Eurasia and Africa via a land bridge in the Levant region. It posits that extended periods of abundant rainfall lasting many thousands of years (pluvial per ...
describes this cycle. During periods of a wet or "Green Sahara
The African humid period (AHP) (also known by other names) is a climate period in Africa during the late Pleistocene and Holocene geologic epochs, when northern Africa was wetter than today. The covering of much of the Sahara desert by grasses, ...
", the Sahara becomes a savanna
A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...
grassland and various flora and fauna become more common. Following inter-pluvial arid periods, the Sahara area then reverts to desert conditions and the flora and fauna are forced to retreat northwards to the Atlas Mountains
The Atlas Mountains are a mountain range in the Maghreb in North Africa. It separates the Sahara Desert from the Mediterranean Sea and the Atlantic Ocean; the name "Atlantic" is derived from the mountain range. It stretches around through Moroc ...
, southwards into West Africa
West Africa or 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, Maurit ...
, or eastwards into the Nile Valley
The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest rive ...
. This separates population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...
s of some of the species in areas with different climate
Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...
s, forcing them to adapt
ADAPT (formerly American Disabled for Attendant Programs Today) is a United States grassroots disability rights organization with chapters in 30 states and Washington, D.C. They use nonviolent direct action in order to bring about disability just ...
, possibly giving rise to allopatric speciation
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...
.
It is also proposed that humans accelerated the drying-out period from 6000 to 2500 BCE by pastoralists overgrazing available grassland.
Evidence for cycles
The growth of speleothems
A speleothem (; ) is a geological formation by mineral deposition (geology), deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety ...
(which requires rainwater) was detected in Hol-Zakh, Ashalim
Ashalim ( he, אֲשָׁלִים) is a small community settlement in southern Israel. Located in the Negev desert about 35 km south of Be'er Sheva and on the eastern side of Nahal Besor, the largest stream in the Negev, it falls under the ju ...
, 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 was just one tenth the rainfall around 125 kya. In the southern Negev Desert
The Negev or Negeb (; he, הַנֶּגֶב, hanNegév; ar, ٱلنَّقَب, an-Naqab) is a desert and semidesert region of southern Israel. The region's largest city and administrative capital is Beersheba (pop. ), in the north. At its southe ...
speleothems did not grow between 185 and 140 kya (MIS
MIS or mis may refer to:
Science and technology
* Management information system
* Marine isotope stage, stages of the Earth's climate
* Maximal independent set, in graph theory
* Metal-insulator-semiconductor, e.g., in MIS capacitor
* Minimally in ...
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
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...
. This suggests that the southern Negev was arid-to-hyper-arid in these periods.
During the Last Glacial Maximum
The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent.
Ice sheets covered much of Northern North America, Northern Eur ...
(LGM) the Sahara desert 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
The Hadley cell, named after George Hadley, is a global-scale tropical atmospheric circulation that features air rising near the equator, flowing poleward at a height of 10 to 15 kilometers above the earth's surface, descending in the subtropics, ...
. This is a climate cell which causes rising tropical air of the Inter-Tropical Convergence Zone
The Intertropical Convergence Zone (ITCZ ), known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal e ...
(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 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 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
The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stage ...
) peaked during the Holocene thermal maximum
The Holocene Climate Optimum (HCO) was a warm period that occurred in the interval roughly 9,000 to 5,000 years ago BP, with a thermal maximum around 8000 years BP. It has also been known by many other names, such as Altithermal, Climatic Optimu ...
climatic phase at 4000 BCE when mid-latitude temperatures seem to have been between 2 and 3 degrees warmer than in the recent past. Analysis of Nile River
The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest rive ...
deposited sediments in the delta also shows this period had a higher proportion of sediments coming from the Blue Nile
The Blue Nile (; ) is a river originating at Lake Tana in Ethiopia. It travels for approximately through Ethiopia and Sudan. Along with the White Nile, it is one of the two major tributaries of the Nile and supplies about 85.6% of the water ...
, suggesting higher rainfall also in the Ethiopian Highlands
The Ethiopian Highlands is a rugged mass of mountains in Ethiopia in Northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below , while the summits reach heights of up to . ...
. This was caused principally by a stronger monsoon
A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscil ...
al circulation throughout the sub-tropical regions, affecting India, Arabia and the Sahara. Lake Victoria
Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropical lake, and the world's second-largest fresh water lake by surface area after ...
only recently became the source of the White Nile
The White Nile ( ar, النيل الأبيض ') is a river in Africa, one of the two main tributaries of the Nile, the other being the Blue Nile. The name comes from the clay sediment carried in the water that changes the water to a pale color. ...
and dried out almost completely around 15 kya.
The sudden subsequent movement of the ITCZ southwards with a Heinrich event
A Heinrich event is a natural phenomenon in which large groups of icebergs break off from glaciers and traverse the North Atlantic. First described by marine geologist Hartmut Heinrich (Heinrich, H., 1988), they occurred during five of the last s ...
(a sudden cooling followed by a slower warming), linked to changes with the El Niño-Southern Oscillation
EL, El or el may refer to:
Religion
* El (deity), a Semitic word for "God"
People
* EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer
* El DeBarge, music artist
* El Franco Lee (1949–2016), American po ...
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 the scale of the Nile floods between 2700 and 2100 BCE.
Ecoregions
The Sahara comprises several distinct ecoregion
An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of l ...
s. With their variations in temperature, rainfall, elevation, and soil, these regions harbor distinct communities of plants and animals.
* The Atlantic coastal desert
The Atlantic coastal desert is the westernmost ecoregion in the Sahara Desert of North Africa. It occupies a narrow strip along the Atlantic coast, where the more frequent fog and haze generated offshore by the cool Canary Current provides suf ...
is a narrow strip along the Atlantic coast where fog generated offshore by the cool Canary Current
The Canary Current is a wind-driven surface current that is part of the North Atlantic Gyre. This eastern boundary current branches south from the North Atlantic Current and flows southwest about as far as Senegal where it turns west and later jo ...
provides sufficient moisture to sustain a variety of lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.[succulents
In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meani ...]
, and shrubs. It covers an area of in the south of Morocco and Mauritania.
* The North Saharan steppe and woodlands
The North Saharan steppe and woodlands is a desert ecoregion, in the deserts and xeric shrublands biome, that forms the northern edge of the Sahara. It extends east and west across Northern Africa, south of the Mediterranean dry woodlands and s ...
is along the northern desert, next to the Mediterranean forests, woodlands, and scrub
Mediterranean forests, woodlands, and scrub is a biome defined by the World Wide Fund for Nature. The biome is generally characterized by dry summers and rainy winters, although in some areas rainfall may be uniform. Summers are typically hot in ...
ecoregions of the northern Maghreb and Cyrenaica. Winter rains sustain shrublands and dry woodlands that form a transition between the Mediterranean climate regions to the north and the hyper-arid Sahara proper to the south. It covers in Algeria, Egypt, Libya, Mauritania, Morocco, and Tunisia.
* The Sahara Desert ecoregion covers the hyper-arid central portion of the Sahara where rainfall is minimal and sporadic. Vegetation is rare, and this ecoregion consists mostly of sand dunes (''erg, chech, raoui''), stone plateaus (''hamadas''), gravel plains (''reg''), dry valleys (''wadis''), and salt flats. It covers of: Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, and Sudan.
* The South Saharan steppe and woodlands
The South Saharan steppe and woodlands, also known as the South Sahara desert, is a deserts and xeric shrublands ecoregion of northern Africa. This band is a transitional region between the Sahara's very arid center (the Sahara desert ecoregion ...
ecoregion is a narrow band running east and west between the hyper-arid Sahara and the Sahel savannas to the south. Movements of the equatorial Intertropical Convergence Zone (ITCZ) bring summer rains during July and August which average but vary greatly from year to year. These rains sustain summer pastures of grasses and herbs, with dry woodlands and shrublands along seasonal watercourses. This ecoregion covers in Algeria, Chad, Mali, Mauritania, and Sudan.
* In the West Saharan montane xeric woodlands
The West Saharan montane xeric woodlands is an ecoregion that extends across several highland regions in the Sahara. Surrounded at lower elevations by the largely barren Sahara, the West Saharan montane xeric woodlands are isolated refuges of pla ...
, several volcanic highlands provide a cooler, moister environment that supports Saharo-Mediterranean woodlands and shrublands. The ecoregion covers , mostly in the Tassili n'Ajjer
Tassili n'Ajjer ( Berber: ''Tassili n Ajjer'', ar, طاسيلي ناجر; "Plateau of rivers") is a national park in the Sahara desert, located on a vast plateau in southeastern Algeria. Having one of the most important groupings of prehistoric ...
of Algeria, with smaller enclaves in the Aïr of Niger, the Adrar Plateau
The Adrar (, Berber for "mountain") is a highland natural and historical region of the Sahara Desert in northern Mauritania. The Adrar Region, an administrative division of Mauritania, is named after the traditional region. It is sometimes cal ...
of Mauritania, and the Adrar des Iforas
The Adrar des Ifoghas (also Adrar des Iforas; Tamasheq: ⴰⴷⵔⴰⵔ ⵏ ⵉⴼⵓⵖⴰⵙ in Tifinagh; Adrar n Ifoghas; ar, أدرار إيفوغاس Ifoghas' Mountains) is a massif located in the Kidal Region of Mali, reaching into Algeri ...
of Mali and Algeria.
* The Tibesti-Jebel Uweinat montane xeric woodlands ecoregion consists of the Tibesti and Jebel Uweinat
Mount Uwaynat or Gabal El Uweinat ( ar, جبل العوينات ', Arabic for 'Mountain of the springs') is a mountain range in the area of the Egyptian-Libyan- Sudanese tripoint. Because of thousands of prehistoric rock art sites, it is consi ...
highlands. Higher and more regular rainfall and cooler temperatures support woodlands and shrublands of date palm, acacia
''Acacia'', commonly known as the wattles or acacias, is a large genus of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa and Australasia. The genus na ...
s, myrtle, oleander
''Nerium oleander'' ( ), most commonly known as oleander or nerium, is a shrub or small tree cultivated worldwide in temperate and subtropical areas as an ornamental and landscaping plant. It is the only species currently classified in the ge ...
, tamarix
The genus ''Tamarix'' (tamarisk, salt cedar, taray) is composed of about 50–60 species of flowering plants in the family Tamaricaceae, native to drier areas of Eurasia and Africa. The generic name originated in Latin and may refer to the Tam ...
, and several rare and endemic plants. The ecoregion covers in the Tibesti of Chad and Libya, and Jebel Uweinat on the border of Egypt, Libya, and Sudan.
* The Saharan halophytics is an area of seasonally flooded saline depressions which is home to halophytic
A halophyte is a salt-tolerant plant that grows in soil or waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs and seashores. T ...
(salt-adapted) plant communities. The Saharan halophytics cover including: the Qattara and Siwa depressions in northern Egypt, the Tunisian salt lakes
The Tunisian salt lakes are a series of lakes in central Tunisia, lying south of the Atlas Mountains at the northern edge of the Sahara. The lakes include, from east to west, the Chott el Fedjedj, Chott el Djerid, and Chott el Gharsa.
Geography ...
of central Tunisia, Chott Melghir
Chott Melrhir () also known as Chott Melghir or Chott Melhir is an endorheic chott-kind of salt lake in northeastern Algeria. It is the westernmost part of a series of Depression (geology), depressions, which extend from the Gulf of Gabès into the ...
in Algeria, and smaller areas of Algeria, Mauritania, and the southern part of Morocco.
* The Tanezrouft
The Tanezrouft ( ar, تنزروفت) is a natural region located along the borders of Algeria and Mali, west of the Hoggar Mountains. Along with the Libyan Desert it is one of the most desolate and most arid parts of the Sahara Desert. This area ha ...
is one of the Sahara's most arid regions, with no vegetation and very little life. A barren, flat gravel plain, it extends south of Reggane
Reggane (from Berber "Argan"; ar, رقان) is a town and commune, and the capital of Reggane District, in Adrar Province, central Algeria. Reggane lies in the Sahara Desert near an oasis. According to the 2008 census it has a population of 20,40 ...
in Algeria towards the Adrar des Ifoghas
The Adrar des Ifoghas (also Adrar des Iforas; Tamasheq: ⴰⴷⵔⴰⵔ ⵏ ⵉⴼⵓⵖⴰⵙ in Tifinagh; Adrar n Ifoghas; ar, أدرار إيفوغاس Ifoghas' Mountains) is a massif located in the Kidal Region of Mali, reaching into Algeri ...
highlands in northern Mali.
Flora and fauna
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 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 plant
Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They al ...
s. Approximately a quarter of these are endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
. About half of these species are common to the flora of the Arabian deserts.
The central Sahara 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 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
Evapotranspiration (ET) is the combined processes by which water moves from the earth’s surface into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpi ...
. Plant leaves may dry out totally and then recover.
Several species of fox live in the Sahara including: the fennec fox
The fennec fox (''Vulpes zerda'') is a small crepuscular fox native to the deserts of North Africa, ranging from Western Sahara to the Sinai Peninsula. Its most distinctive feature is its unusually large ears, which serve to dissipate heat and l ...
, pale fox
The pale fox (''Vulpes pallida'') is a species of fox found in the band of African Sahel from Senegal in the west to Sudan in the east. It is one of the least studied of all canid species, in part due to its remote habitat and its sandy coat tha ...
and Rüppell's fox
Rüppell's fox (''Vulpes rueppellii''), also called Rüppell's sand fox, is a fox species living in desert and semi-desert regions of North Africa, the Middle East, and southwestern Asia. It has been listed as Least Concern on the IUCN Red List s ...
. The addax
The addax (''Addax nasomaculatus''), also known as the white antelope and the screwhorn antelope, is an antelope native to the Sahara Desert. The only member of the genus ''Addax'', it was first described scientifically by Henri de Blainvil ...
, a large white antelope
The term antelope is used to refer to many species of even-toed ruminant that are indigenous to various regions in Africa and Eurasia.
Antelope comprise a wastebasket taxon defined as any of numerous Old World grazing and browsing hoofed mammals ...
, can go nearly a year in the desert without drinking. The dorcas gazelle
The dorcas gazelle (''Gazella dorcas''), also known as the ariel gazelle, is a small and common gazelle. The dorcas gazelle stands about at the shoulder, with a head and body length of and a weight of . The numerous subspecies survive on vegeta ...
is a north African gazelle that can also go for a long time without water. Other notable gazelles include the rhim gazelle
The rhim gazelle or rhim (''Gazella leptoceros''), also known as the slender-horned gazelle, African sand gazelle or Loder's gazelle, is a pale-coated gazelle with long slender horns and well adapted to desert life. It is considered an endangered ...
and dama gazelle
The dama gazelle (''Nanger dama''), also known as the addra gazelle or mhorr gazelle, is a species of gazelle. It lives in Africa, in the Sahara desert and the Sahel. A critically endangered species, it has disappeared from most of its former r ...
.
The Saharan cheetah
The cheetah (''Acinonyx jubatus'') is a large cat native to Africa and central Iran. It is the fastest land animal, estimated to be capable of running at with the fastest reliably recorded speeds being , and as such has evolved specialized ...
(northwest African cheetah
The Northwest African cheetah (''Acinonyx jubatus hecki''), also known as the Saharan cheetah, is a cheetah subspecies native to the Sahara and the Sahel. It is listed as Critically Endangered on the IUCN Red List. In 2008, the population was su ...
) lives in Algeria, Togo
Togo (), officially the Togolese Republic (french: République togolaise), is a country in West Africa. It is bordered by Ghana to the west, Benin to the east and Burkina Faso to the north. It extends south to the Gulf of Guinea, where its c ...
, Niger, Mali, Benin
Benin ( , ; french: Bénin , ff, Benen), officially the Republic of Benin (french: République du Bénin), and formerly Dahomey, is a country in West Africa. It is bordered by Togo to the west, Nigeria to the east, Burkina Faso to the north ...
, and Burkina Faso
Burkina Faso (, ; , ff, 𞤄𞤵𞤪𞤳𞤭𞤲𞤢 𞤊𞤢𞤧𞤮, italic=no) is a landlocked country in West Africa with an area of , bordered by Mali to the northwest, Niger to the northeast, Benin to the southeast, Togo and Ghana to the ...
. 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 the shelter of shrubs such as balanites
''Balanites'' is an Afrotropical, Palearctic and Indomalayan genus of flowering plants in the caltrop family, Zygophyllaceae. The name ''Balanites'' derives from the Greek word for an acorn and refers to the fruit, it was coined by Alire Del ...
and acacias. They are unusually pale. The other cheetah subspecies (northeast African cheetah
The Northeast African cheetah (''Acinonyx jubatus soemmeringii'') is a cheetah subspecies occurring in Northeast Africa. Contemporary records are known in South Sudan and Ethiopia, but population status in Eritrea, Djibouti, Somalia and Sudan is ...
) 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 lizard
Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recogn ...
s, hyrax
Hyraxes (), also called dassies, are small, thickset, herbivorous mammals in the order Hyracoidea. Hyraxes are well-furred, rotund animals with short tails. Typically, they measure between long and weigh between . They are superficially simil ...
, sand vipers, and small populations of African wild dog
The African wild dog (''Lycaon pictus''), also called the painted dog or Cape hunting dog, is a wild canine which is a native species to sub-Saharan Africa. It is the largest wild canine in Africa, and the only extant member of the genus '' Ly ...
, in perhaps only 14 countries and red-necked ostrich
The North African ostrich, red-necked ostrich, or Barbary ostrich (''Struthio camelus camelus'') is the nominate subspecies of the common ostrich from West and North Africa. It is the largest subspecies, making it the largest living bird.
Evolu ...
. Other animals exist in the Sahara (birds in particular) such as African silverbill
The African silverbill (''Euodice cantans'') is a small passerine bird formerly considered conspecific with the Asian species Indian silverbill, (''Euodice malabarica''). This estrildid finch is a common resident breeding bird in dry savanna h ...
and black-faced firefinch
The black-faced firefinch (''Lagonosticta larvata'') is a common species of estrildid finch found in Africa. It has an estimated global extent of occurrence of 2,100,000 km2.
It is found in Benin, Burkina Faso, Cameroon, Central African Rep ...
, among others. There are also small desert crocodile
The West African crocodile, desert crocodile, or sacred crocodile (''Crocodylus suchus'') is a species of crocodile related to – and often confused with – the larger and more aggressive Nile crocodile (''C. niloticus'').
Taxonomy
Compared ...
s in Mauritania and the Ennedi Plateau
The Ennedi Plateau is located in the northeast of Chad, in the regions of Ennedi-Ouest and Ennedi-Est. It is considered a part of the group of mountains known as the Ennedi Massif found in Chad, which is one of the nine countries that make up t ...
of Chad.
The deathstalker
The deathstalker (''Leiurus quinquestriatus'') is a species of scorpion, a member of the family Buthidae. It is also known as the Palestine yellow scorpion, Omdurman scorpion, Naqab desert scorpion and by many other colloquial names, which gene ...
scorpion can be long. Its venom contains large amounts of agitoxin
Agitoxin is a toxin found in the venom of the scorpion '' Leiurus quinquestriatus hebraeus'' (yellow scorpion). Other toxins found in this species include charybdotoxin (CTX). CTX is a close homologue of Agitoxin.
Structure
Agitoxin can be p ...
and scyllatoxin
Scyllatoxin (also leiurotoxin I) is a toxin, from the scorpion '' Leiurus quinquestriatus hebraeus'', which blocks small-conductance Ca2+-activated K+ channels. It is named after Scylla, a sea monster from Greek mythology. Charybdotoxin is also f ...
and is very dangerous; however, a sting from this scorpion rarely kills a healthy adult. The Saharan silver ant
The Saharan silver ant (''Cataglyphis bombycina'') is a species of insect that lives in the Sahara Desert. It is the fastest of the world’s 12,000 known ant species, clocking a velocity of 855 millimetres per second (over ). It can travel a len ...
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
The dromedary (''Camelus dromedarius'' or ;), also known as the dromedary camel, Arabian camel, or one-humped camel, is a large even-toed ungulate, of the genus ''Camelus'', with one hump on its back.
It is the tallest of the three species of ...
camels and goat
The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...
s 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 nomad
A nomad is a member of a community without fixed habitation who regularly moves to and from the same areas. Such groups include hunter-gatherers, pastoral nomads (owning livestock), tinkers and trader nomads. In the twentieth century, the popu ...
s.
Human activities are more likely to affect 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
Soil retrogression and degradation are two regressive evolution processes associated with the loss of equilibrium of a stable soil. Retrogression is primarily due to soil erosion and corresponds to a phenomenon where succession reverts the land t ...
and salinization.
Researchers from Hacettepe University
Hacettepe University is a leading state university in Ankara, Turkey. It was established on 8 July 1967. It is ranked first among the Turkish universities by URAP in 2021.
The university has two main campuses. The first campus is in the old to ...
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.
History
People lived on the edge of the desert thousands of years ago,[Discover Magazine](_blank)
2006-Oct. 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
Bubalus, Bubaline, or Large Wild Fauna rock art is the earliest form of Central Saharan rock art, created in an petroglyph, engraved style, which have been dated between 12,000 BCE and 8000 BCE. The Bubaline Period is followed by the Kel Essuf P ...
, Kel Essuf Period
Kel Essuf rock art is the earliest form of engraved anthropomorphic Central Saharan rock art, which was produced prior to 9800 BP, at least as early as 12,000 BP amid the Late Pleistocene, late period of the Pleistocene. The Kel Essuf Period is pr ...
, Round Head Period
Round Head rock art is the earliest painted, monumental form of Central Saharan rock art, which was largely created from 9500 BP to 7500 BP and ceased being created by 3000 BP. The Round Head Period is preceded by the Kel Essuf Period and follo ...
, Pastoral Period, Caballine Period, and Cameline Period. The Sahara was then a much wetter place than it is today. Over 30,000 petroglyph
A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions ...
s of river animals such as crocodile
Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...
s[National Geographic News]
17 June 2006. survive, with half found in the Tassili n'Ajjer in southeast Algeria. Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s of dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s, including ''Afrovenator
''Afrovenator'' (; "African hunter") is a genus of megalosaurid theropod dinosaur from the Middle Jurassic Period of northern Africa.
Discovery and naming
The remains of ''Afrovenator'' were discovered in 1993 in the Tiourarén Formation ...
'', ''Jobaria
''Jobaria'' is a genus of sauropod dinosaur that lived in what is now Niger during the middle Jurassic Period, between 164 and 161 million years ago. ''Jobaria'' is currently the only known valid sauropod from the Tiouraren, where it was discov ...
'' and ''Ouranosaurus
''Ouranosaurus'' is a genus of herbivorous basal hadrosauriform dinosaur that lived during the Aptian stage of the Early Cretaceous of modern-day Niger and Cameroon. ''Ouranosaurus'' measured about long. Two rather complete fossils were found in ...
'', have also been found here. The modern Sahara, though, is not lush in vegetation, except in the Nile
The Nile, , Bohairic , lg, Kiira , Nobiin language, Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered ...
Valley, at a few oases
In ecology, an oasis (; ) is a fertile area of a desert or semi-desert environment'ksar''with its surrounding feeding source, the palm grove, within a relational and circulatory nomadic system.”
The location of oases has been of critical imp ...
, and in the northern highlands, where Mediterranean plants such as the olive
The olive, botanical name ''Olea europaea'', meaning 'European olive' in Latin, is a species of small tree or shrub in the family Oleaceae, found traditionally in the Mediterranean Basin. When in shrub form, it is known as ''Olea europaea'' ...
tree are found to grow. It was long believed that the region had been this way since about 1600 BCE, after shifts in Earth's axis
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle between its equatorial plane and orbit ...
increased temperatures and decreased precipitation, which led to the abrupt desertification of North Africa about 5,400 years ago.
Kiffians
The Kiffian culture
The Kiffian culture is a prehistoric industry, or domain, that existed between approximately 8,000 BC and 6,000 BC in the Sahara Desert, during the African humid period referred to as the Neolithic Subpluvial. Human remains from this culture were ...
is a prehistoric industry, or domain, that existed between 10,000 and 8,000 years ago in the Sahara, during the Neolithic Subpluvial
The African humid period (AHP) (also known by other names) is a climate period in Africa during the late Pleistocene and Holocene geologic epochs, when northern Africa was wetter than today. The covering of much of the Sahara desert by grasses, ...
. Human remains from this culture were found in 2000 at a site known as Gobero
The Gobero archaeological site, dating to approximately 8000 BCE, is the oldest known graveyard in the Sahara Desert. The site contains important information for archaeologists on how early humans adapted to a constantly changing environment. Gobe ...
, located in Niger
)
, official_languages =
, languages_type = National languages[Ténéré Desert
The Ténéré (Tuareg: Tenere, literally: "desert") is a desert region in the south central Sahara. It comprises a vast plain of sand stretching from northeastern Niger into western Chad, occupying an area of over . The Ténéré's boundaries are ...](_blank)
. The site is known as the largest and earliest grave of Stone Age people in the Sahara desert. The Kiffians were skilled hunters
Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/ hide, bone/tusks, horn/antler, et ...
. Bones of many large savannah animals that were discovered in 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
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...
population was closely related to the Late Pleistocene Iberomaurusian
The Iberomaurusian is a backed bladelet lithic industry found near the coasts of Morocco, Algeria, and Tunisia. It is also known from a single major site in Libya, the Haua Fteah, where the industry is locally known as the Eastern Oranian.The " ...
s and early Holocene Capsians of the Maghreb, as well as mid-Holocene Mechta groups. Traces of 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
The Tenerian culture is a prehistoric industry that existed between the 5th millennium BC and mid-3rd millennium BC in the Sahara Desert. This spans the Neolithic Subpluvial and later desiccation, during the middle Holocene.
French archaeologist ...
colonized the area.
Tenerians
Gobero was discovered in 2000 during an archaeological expedition led by Paul Sereno
Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago and a National Geographic "explorer-in-residence" who has discovered several new dinosaur species on several continents, including at sites ...
, which sought dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
remains. Two distinct prehistoric cultures were discovered at the site: the early Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...
Kiffian culture, and the middle Holocene Tenerian culture
The Tenerian culture is a prehistoric industry that existed between the 5th millennium BC and mid-3rd millennium BC in the Sahara Desert. This spans the Neolithic Subpluvial and later desiccation, during the middle Holocene.
French archaeologist ...
. 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 the Late Pleistocene
The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division of ...
Iberomaurusian
The Iberomaurusian is a backed bladelet lithic industry found near the coasts of Morocco, Algeria, and Tunisia. It is also known from a single major site in Libya, the Haua Fteah, where the industry is locally known as the Eastern Oranian.The " ...
s, 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 tusk
Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with pigs and walruses, or, in the case of elephants, elongated incisors. Tusks share c ...
s 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 a bed of flowers. The three are assumed to have died within 24 hours of each other, but as their skeletons hold no apparent trauma (they did not die violently) and they have been buried so elaborately – unlikely if they had died of a plague – the cause of their deaths is a mystery.
Tashwinat Mummy
Uan Muhuggiag
Uan Muhuggiag is an archaeological site in Libya. It was occupied by pastoralists during the early- to mid-Holocene. The site is where the Tashwinat Mummy was found, which was dated to around 5600 BP. It now resides in the Assaraya Alhamra Museum ...
appears to have been inhabited from at least the 6th millennium BCE to about 2700 BCE, although not necessarily continuously. The most noteworthy find at Uan Muhuggiag is the well-preserved mummy
A mummy is a dead human or an animal whose soft tissues and organs have been preserved by either intentional or accidental exposure to chemicals, extreme cold, very low humidity, or lack of air, so that the recovered body does not decay fu ...
of a young boy of approximately years old. The child was in a fetal position, then embalmed, then placed in a sack made of antelope skin, which was insulated by a layer of leaves. The boy's organs were removed, as evidenced by incisions in his stomach and thorax, and an organic preservative was inserted to stop his body from decomposing. An ostrich eggshell necklace was also found around his neck. Radiocarbon dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.
The method was dev ...
determined the age of the mummy to be approximately 5600 years old, which makes it about 1000 years older than the earliest previously recorded mummy in ancient Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
. In 1958–59, an archaeological expedition led by Antonio Ascenzi
Antonio is a masculine given name of Etruscan origin deriving from the root name Antonius. It is a common name among Romance language-speaking populations as well as the Balkans and Lusophone Africa. It has been among the top 400 most popular male ...
conducted anthropological, radiological, histological and chemical analyses on the Uan Muhuggiag mummy. The team claimed that the mummy was a 30-month-old child of uncertain sex who possessed Negroid
Negroid (less commonly called Congoid) is an obsolete racial grouping of various people indigenous to Africa south of the area which stretched from the southern Sahara desert in the west to the African Great Lakes in the southeast, but also to i ...
features (Note: "negroid" is derived from a disproven theory of biological race, and modern genetics has since rendered such terminology obsolete). A long incision on the specimen's abdominal wall also indicated that the body had been initially mummified by evisceration and later underwent natural desiccation. One other individual, an adult, was found at Uan Muhuggiag, buried in a crouched position. However, the body showed no evidence of evisceration or any other method of preservation. The body was estimated to date from about 7500 BP.
Nubians
During the Neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
Era, before the onset of desertification
Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid. It is the spread of arid areas caused by ...
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
Nubia () (Nobiin: Nobīn, ) is a region along the Nile river encompassing the area between the first cataract of the Nile (just south of Aswan in southern Egypt) and the confluence of the Blue and White Niles (in Khartoum in central Sudan), or ...
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
Due to the multiple benefits from cattle, there are varying beliefs about cattle in societies and religions. In some regions, especially most states of India, the slaughter of cattle is prohibited and their meat may be taboo.
Cattle are consider ...
like those found in Sudan and other pastoral societies in Africa today. Megalith
A megalith is a large stone that has been used to construct a prehistoric structure or monument, either alone or together with other stones. There are over 35,000 in Europe alone, located widely from Sweden to the Mediterranean sea.
The ...
s found at Nabta Playa
Nabta Playa was once a large internally drained basin in the Nubian Desert, located approximately 800 kilometers south of modern-day Cairo or about 100 kilometers west of Abu Simbel in southern Egypt, 22.51° north, 30.73° east. T ...
are overt examples of probably the world's first known archaeoastronomy
Archaeoastronomy (also spelled archeoastronomy) is the interdisciplinary or multidisciplinary study of how people in the past "have understood the phenomena in the sky, how they used these phenomena and what role the sky played in their cultur ...
devices, predating Stonehenge
Stonehenge is a prehistoric monument on Salisbury Plain in Wiltshire, England, west of Amesbury. It consists of an outer ring of vertical sarsen standing stones, each around high, wide, and weighing around 25 tons, topped by connectin ...
by some 2,000 years. This complexity, as observed at Nabta Playa, and as expressed by different levels of authority within the society there, likely formed the basis for the structure of both the Neolithic society at Nabta and the Old Kingdom of Egypt.
Archaeological evidence has attested that population settlements occurred in Nubia as early as the Late Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
era and from the 5th millennium BC onwards, whereas there is "no or scanty evidence" of human presence in the Egyptian Nile Valley during these periods, which may be due to problems in site preservation.
Egyptians
By 6000 BCE predynastic Egypt
Prehistoric Egypt and Predynastic Egypt span the period from the earliest human settlement to the beginning of the Early Dynastic Period around 3100 BC, starting with the first Pharaoh, Narmer for some Egyptologists, Hor-Aha for others, with th ...
ians 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. Metal objects replaced prior ones of stone. Tanning of animal skins, pottery and weaving were commonplace in this era also. There are indications of seasonal or only temporary occupation of the Al Fayyum
Faiyum ( ar, الفيوم ' , borrowed from cop, ̀Ⲫⲓⲟⲙ or Ⲫⲓⲱⲙ ' from egy, pꜣ ym "the Sea, Lake") is a city in Middle Egypt. Located southwest of Cairo, in the Faiyum Oasis, it is the capital of the modern Faiyum ...
in the 6th millennium BCE, with food activities centering on fishing, hunting and food-gathering. Stone arrowhead
An arrowhead or point is the usually sharpened and hardened tip of an arrow, which contributes a majority of the projectile mass and is responsible for impacting and penetrating a target, as well as to fulfill some special purposes such as sign ...
s, knives and scrapers from the era are commonly found.[Fayum, Qarunian]
(Fayum B, about 6000–5000 BCE?)
Digital Egypt
Burial items included pottery, jewelry, farming and hunting equipment, and assorted foods including dried meat and fruit. Burial in desert environments appears to enhance Egyptian preservation rites, and the dead were buried facing due west.[Predynastic (5,500–3,100 BCE), Tour Egypt.] Several scholars have argued that the African origins of the Egyptian civilisation derived from pastoral communities which emerged in both the Egyptian and Sudanese regions of the Nile Valley in the fifth millennium BCE.
By 3400 BCE, the Sahara was as dry as it is today, due to reduced precipitation and higher temperatures resulting from a shift in Earth's orbit. As a result of this aridification, it became a largely impenetrable barrier to humans, with the remaining settlements mainly being concentrated around the numerous oases that dot the landscape. Little trade or commerce is known to have passed through the interior in subsequent periods, the only major exception being the Nile Valley. The Nile, however, was impassable at several cataracts
A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colors, blurry or double vision, halos around light, trouble w ...
, making trade and contact by boat difficult.
Tichitt culture
In 4000 BCE, the start of sophisticated social structure (e.g., trade of cattle as valued assets) developed among herders amid the Pastoral Period of the Sahara. Saharan pastoral
A pastoral lifestyle is that of shepherds herding livestock around open areas of land according to seasons and the changing availability of water and pasture. It lends its name to a genre of literature, art, and music (pastorale) that depicts ...
culture (e.g., fields of tumuli, lustrous stone rings, axes) was intricate. By 1800 BCE, Saharan pastoral culture expanded throughout the Saharan and Sahelian regions. The initial stages of sophisticated social structure among Saharan herders served as the segue for the development of sophisticated hierarchies
A hierarchy (from Greek: , from , 'president of sacred rites') is an arrangement of items (objects, names, values, categories, etc.) that are represented as being "above", "below", or "at the same level as" one another. Hierarchy is an important ...
found in African settlements, such as Dhar Tichitt
Dhar Tichitt is a Neolithic archaeological site located in the southwestern region of the Sahara Desert, in Mauritania. It is one of several settlement locations along the sandstone cliffs in the area. Dhar Tichitt, Dhar Walata, Dhar Néma, an ...
. After migrating from the Central Sahara, Mande peoples Mande may refer to:
* Mandé peoples of western Africa
* Mande languages
* Manding, a term covering a subgroup of Mande peoples, and sometimes used for one of them, Mandinka
* Garo people of northeastern India and northern Bangladesh
* Mande Rive ...
established their civilization in the Tichitt region of the Western Sahara The Tichitt Tradition of eastern Mauritania dates from 2200 BCE to 200 BCE. Tichitt culture, at Dhar Néma, Dhar Tagant, Dhar Tichitt, and Dhar Walata, included a four-tiered hierarchal social structure, farming
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...
of cereals
A cereal is any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grain crops are grown in greater quantities and provide more food en ...
, metallurgy
Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys.
Metallurgy encompasses both the sc ...
, numerous funerary
A funeral is a ceremony connected with the Disposal of human corpses, final disposition of a corpse, such as a burial or cremation, with the attendant observances. Funerary customs comprise the complex of beliefs and practices used by a culture ...
tombs, and a rock art
In archaeology, rock art is human-made markings placed on natural surfaces, typically vertical stone surfaces. A high proportion of surviving historic and prehistoric rock art is found in caves or partly enclosed rock shelters; this type also ...
tradition At Dhar Tichitt and Dhar Walata, pearl millet
Pearl millet (''Cenchrus americanus'', commonly known as the synonym ''Pennisetum glaucum''; also known as 'Bajra' in Hindi, 'Sajje' in Kannada, 'Kambu' in Tamil, 'Bajeer' in Kumaoni and 'Maiwa' in Hausa, 'Mexoeira' in Mozambique) is the most w ...
may have also been independently tamed amid the Neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
. The urban
Urban means "related to a city". In that sense, the term may refer to:
* Urban area, geographical area distinct from rural areas
* Urban culture, the culture of towns and cities
Urban may also refer to:
General
* Urban (name), a list of people ...
Tichitt Tradition may have been the earliest large-scale, complexly organized society in West Africa
West Africa or 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, Maurit ...
, and an early civilization
A civilization (or civilisation) is any complex society characterized by the development of a state, social stratification, urbanization, and symbolic systems of communication beyond natural spoken language (namely, a writing system).
Ci ...
of the Sahara, which may have served as the segue for state formation
State formation is the process of the development of a centralized government structure in a situation where one did not exist prior to its development. State formation has been a study of many disciplines of the social sciences for a number of ...
in West Africa.
As areas where the Tichitt cultural tradition were present, Dhar Tichitt and Dhar Walata were occupied more frequently than Dhar Néma. Farming of crops (e.g., millet
Millets () are a highly varied group of small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. Most species generally referred to as millets belong to the tribe Paniceae, but some millets al ...
) may have been a feature of the Tichitt cultural tradition as early as 3rd millennium BCE in Dhar Tichitt.
As part of a broader trend of iron metallurgy developed in the West African Sahel amid 1st millennium BCE, iron items (350 BCE – 100 CE) were found at Dhar Tagant, iron metalworking and/or items (800 BCE – 400 BCE) were found at Dia Shoma and Walaldé, and the iron remnants (760 BCE – 400 BCE) found at Bou Khzama and Djiganyai. The iron materials that were found are evidence of iron metalworking at Dhar Tagant. In the late period of the Tichitt Tradition at Dhar Néma, tamed pearl millet was used to temper the tuyeres of a oval-shaped low shaft furnace; this furnace was one out of 16 iron furnaces located on elevated ground. Iron metallurgy
Ferrous metallurgy is the metallurgy of iron and its alloys. The earliest surviving prehistory, prehistoric iron artifacts, from the 4th millennium BC in Egypt, were made from meteorite, meteoritic Iron–nickel alloy, iron-nickel. It is not know ...
may have developed before the second half of 1st millennium BCE, as indicated by pottery dated between 800 BCE and 200 BCE. At Dhar Walata and Dhar Tichitt, copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
was also used.
After its decline in Mauritania, the Tichitt Tradition spread to the Middle Niger region (e.g., Méma
Méma is a region in Mali, Africa. A plain of alluvial deposits, it is situated north of Massina; west of Lake Debo and the Inner Niger Delta; and southwest of the Lakes Region. The now-senescent basin may have been the first settlement area for ...
, Macina, Dia Shoma, Jenne Jeno Jenne can refer to:
*Djenné, a city of Mali
* Jenne, Lazio, a city and comune in the Metropolitan City of Rome, Italy
People with the given name
* Jenne Langhout (1918–2010), Dutch field hockey player
* Jenne Lennon (), American singer
People ...
) of Mali where it developed into and persisted as Faïta Facies ceramics between 1300 BCE and 400 BCE among rammed earth
Rammed earth is a technique for constructing foundations, floors, and walls using compacted natural raw materials such as earth, chalk, lime, or gravel. It is an ancient method that has been revived recently as a sustainable building method.
...
architecture and iron metallurgy (which had developed after 900 BCE). Thereafter, the Ghana Empire developed in the 1st millennium CE.
Phoenicians
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. This put them in contact with the people of ancient Libya, who were the ancestors of people who speak Berber languages in North Africa and the Sahara today.
The Libyco-Berber alphabet of the ancient Libyans of north Africa seems to have been based on Phoenician, and its descendant Tifinagh is still used today by the (Berber) Tuareg people, Tuareg of the central Sahara.
The Periplus of the Phoenician navigator Hanno the Navigator, Hanno, who lived sometime in the 5th century BC, claims that he founded settlements along the Atlantic coast of Africa, possibly including the Western Sahara. The identification of the places discussed is controversial, and archeological confirmation is lacking.
Greeks
By 500 BCE, Ancient Greece, Greeks arrived in the desert. Greek traders spread along the eastern coast of the desert, establishing trading colonies along the Red Sea
The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...
. The Carthage, Carthaginians explored the Atlantic coast of the desert, but the turbulence of the waters and the lack of markets caused a lack of presence further south than modern Morocco. Centralized states thus surrounded the desert on the north and east; it remained outside the control of these states. Raids from the nomadic Berber people of the desert were of constant concern to those living on the edge of the desert.
Urban civilization
An urban civilization, the Garamantes, arose around 500 BCE in the heart of the Sahara, in a valley that is now called the Wadi al-Ajal in Fezzan, Libya. The Garamantes achieved this development by digging tunnels far into the mountains flanking the valley to tap fossil water and bring it to their fields. The Garamantes grew populous and strong, conquering their neighbors and capturing many slaves (who were put to work extending the tunnels). The ancient Greeks and the Ancient Rome, Romans knew of the Garamantes and regarded them as uncivilized nomads. However, they traded with them, and a Roman bath has been found in the Garamantes' capital of Garama. Archaeology, Archaeologists have found eight major towns and many other important settlements in the Garamantes' territory. The Garamantes' civilization eventually collapsed after they had depleted available water in the aquifers and could no longer sustain the effort to extend the tunnels further into the mountains.
Between the first century BCE and the fourth century CE, several Romans in Sub-Saharan Africa, Roman expeditions into the Sahara were conducted by groups of military and commercial units of Roman Empire, Romans.
Berbers
The Berber people occupied (and still occupy with Arabs) much of the Sahara. The Garamantes Berbers built a prosperous empire in the heart of the desert. The Tuareg nomads continue to inhabit and move across wide Sahara surfaces to the present day.
Islamic and Arabic expansion
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. By the end of 641 all of Egypt was in Muslim hands. Trade across the desert intensified, and a significant slave trade crossed the desert. It has been estimated that from the 10th to 19th centuries some 6,000 to 7,000 slaves were transported north each year.
The Beni Ḥassān and other nomadic Arab tribes dominated the Sanhaja Berber people, Berber tribes of the western Sahara after the Char Bouba war of the 17th century. As a result, Arabian culture and language came to dominate, and the Berber tribes underwent some Arabization.
Ottoman Turkish era
In the 16th century the northern fringe of the Sahara, such as coastal regencies in present-day Ottoman Algeria, Algeria and Tunisia, as well as some parts of present-day Libya, together with the semi-autonomous kingdom of Egypt, were occupied by the Ottoman Empire. From 1517 Egypt was a valued part of the Ottoman Empire, ownership of which provided the Ottomans with control over the Nile Valley, the east Mediterranean and North Africa. The benefit of the Ottoman Empire was the freedom of movement for citizens and goods. Traders exploited the Ottoman land routes to handle the spices, gold and silk from the East, manufactured goods from Europe, and the slave and gold traffic from Africa. Arabic continued as the local language and Islamic culture was much reinforced. The Sahel and southern Sahara regions were home to several independent states or to roaming Tuareg clans.
European colonialism
European colonialism in the Sahara began in the 19th century. July Monarchy, France conquered the regency of Algiers from the Ottomans in 1830, and French rule spread south from French Algeria and eastwards from French Senegal, Senegal into the upper Niger River, Niger to include present-day Algeria, Chad, Mali then French Sudan including Timbuktu
Timbuktu ( ; french: Tombouctou;
Koyra Chiini: ); tmh, label=Tuareg, script=Tfng, ⵜⵏⴱⴾⵜ, Tin Buqt a city in Mali, situated north of the Niger River. The town is the capital of the Tombouctou Region, one of the eight administrativ ...
(1893), Mauritania, Morocco (1912), Niger, and Tunisia (1881). By the beginning of the 20th century, the trans-Saharan trade had clearly declined because goods were moved through more modern and efficient means, such as airplanes, rather than across the desert.
The French took advantage of long-standing animosity between the Chaamba Arabs and the Tuareg. The newly raised ''Méhariste'' Méhariste, camel corps were originally recruited mainly from the Chaamba nomadic tribe. In 1902, the French penetrated Hoggar Mountains and defeated Kel Ahaggar, Ahaggar Tuareg in the battle of Tit, Tamanrasset, Tit.
The French Colonial Empire was the dominant presence in the Sahara. It established regular air links from Toulouse (HQ of famed Aéropostale (aviation), Aéropostale), to Oran and over the Hoggar to Timbuktu and West to Bamako and Dakar, as well as trans-Sahara bus services run by La Compagnie Transsaharienne (est. 1927). A remarkable film shot by famous aviator Captain René Wauthier documents the first crossing by a large truck convoy from Algiers to Tchad, across the Sahara.
Egypt, under Muhammad Ali of Egypt, Muhammad Ali and his successors, conquered Nubia in 1820–22, founded Khartoum in 1823, and conquered Darfur in 1874. Egypt, including the Sudan, became a British protectorate in 1882. Egypt and United Kingdom of Great Britain and Ireland, Britain lost control of the Sudan from 1882 to 1898 as a result of the Mahdist War. After its capture by British troops in 1898, the Sudan became an Anglo-Egyptian condominium (international law), condominium.
Restoration (Spain), Spain captured present-day Western Sahara
Western Sahara ( '; ; ) is a disputed territory on the northwest coast and in the Maghreb region of North and West Africa. About 20% of the territory is controlled by the self-proclaimed Sahrawi Arab Democratic Republic (SADR), while the r ...
after 1874, although Rio del Oro remained largely under Sahrawi people, Sahrawi influence. In 1912, Kingdom of Italy, Italy captured parts of what was to be named Ottoman Libya, Libya from the Ottomans. To promote the Roman Catholic religion in the desert, Pope Pius IX appointed a delegate Apostolic of the Sahara and the Sudan in 1868; later in the 19th century his jurisdiction was reorganized into the Vicariate Apostolic of Sahara.
Breakup of the empires and afterwards
Egypt became independent of Britain in 1936, although the Anglo-Egyptian treaty of 1936 allowed Britain to keep troops in Egypt and to maintain the British-Egyptian condominium in the Sudan. British military forces were withdrawn in 1954.
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. Spain withdrew from Western Sahara
Western Sahara ( '; ; ) is a disputed territory on the northwest coast and in the Maghreb region of North and West Africa. About 20% of the territory is controlled by the self-proclaimed Sahrawi Arab Democratic Republic (SADR), while the r ...
in 1975, and it was partitioned between Mauritania and Morocco. Mauritania withdrew in 1979; Morocco continues to hold the territory (see Western Sahara conflict).
Tuareg people in Mali Tuareg rebellions (disambiguation), rebelled several times during the 20th century before finally forcing the Malian armed forces to withdraw below the line demarcating Azawad from southern Mali during the Tuareg rebellion (2012), 2012 rebellion. Islamist rebels in the Sahara calling themselves al-Qaeda in the Islamic Maghreb have stepped up their violence in recent years.
In the post–World War II era, several mining, mines and communities have developed to use the desert's natural resources. These include large deposits of petroleum, oil and natural gas in Algeria and Libya, and large deposits of phosphates in Morocco and Western Sahara. Libya's Great Man-Made River is the world's largest irrigation project. The project uses a pipeline system that pumps fossil water from the Nubian Sandstone Aquifer System to cities in the populous Libyan northern Mediterranean coast including Tripoli and Benghazi.
A number of Trans-African Highway network, Trans-African highways have been proposed across the Sahara, including the Cairo–Dakar Highway along the Atlantic coast, the Trans-Sahara Highway from Algiers on the Mediterranean to Kano (city), Kano in Nigeria, the Tripoli – Cape Town Highway from Tripoli, Libya, Tripoli in Libya to N'Djamena in Chad, and the Cairo – Cape Town Highway which follows the Nile. Each of these highways is partially complete, with significant gaps and unpaved sections.
People, culture, and languages
The people of the Sahara are of various origins. Among them the Amazigh including the Tuareg people, Tuareg, various Arabized Amaziɣ groups such as the Hassaniya-speaking Sahrawis, whose populations include the Znaga, a tribe whose name is a remnant of the pre-historic Zenaga language. Other major groups of people include the: Toubou, Nubians, Zaghawa people, Zaghawa, Kanuri people, Kanuri, Hausa people, Hausa, Songhai people, Songhai, Beja people, Beja, and Fula people, Fula/Fulani (french: Peul; ff, Fulɓe). The archaeological evidence from the Holocene period has shown that Nilo-Saharan speaking groups had populated the central and southern Sahara before the influx of Berber languages, Berber and Arabic speakers, around 1500 years ago, who now largely populate the Sahara in the modern era.
Arabic dialects are the most widely spoken languages in the Sahara. Arabic, Berber and its variants now regrouped under the term Amazigh (which includes the Guanche language spoken by the original Berber inhabitants of the Canary Islands) and Beja languages are part of the Afro-Asiatic or Hamito-Semitic family. Unlike neighboring West Africa
West Africa or 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, Maurit ...
and the central governments of the states that comprise the Sahara, the French language bears little relevance to inter-personal discourse and commerce within the region, its people retaining staunch ethnic and political affiliations with Tuareg and Berbers, Berber leaders and culture. The legacy of the French French North Africa, colonial era administration is primarily manifested in the territorial reorganization enacted by the French Third Republic, Third and French Fourth Republic, Fourth republics, which engendered artificial political divisions within a hitherto isolated and porous region. Diplomacy with local clients was conducted primarily in Arabic, which was the traditional language of bureaucratic affairs. Mediation of disputes and inter-agency communication was served by interpreters contracted by the French government, who, according to Keenan, "documented a space of intercultural mediation," contributing much to preserving the indigenous cultural identities in the region.[Jeremy Keenan, ed. (2013). ''The Sahara: Past, Present and Future''. Routledge, ]
See also
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Notes
References
Bibliography
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* Republished with a new preface Columbia University Press, 1990.
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External links
About Sahara subsurface hydrology
and planned usage of the aquifers]
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{{Authority control
Sahara,
Articles containing video clips
Deserts and xeric shrublands
Deserts of Africa
Geography of North Africa
Geography of the Arab world
Palearctic realm
Physiographic provinces