Editing Sahel (section)

== Geography ==
[[File:Sahel forest near Kayes Mali.jpg|thumb|right|The lush green of the Sahelian acacia savanna during the [[Semi-arid climate#Hot semi-arid climates|rainy summer season]] in [[Mali]]. Note the large [[Adansonia digitata|baobab]] amongst the acacia.]]
[[File:Azawakh 52 jd.jpg|thumb|right|Herders with livestock and [[azawakh]] dogs in the Sahel]]

The Sahel spans {{convert|5900|km|mi|-1|abbr=on}} from the [[Atlantic Ocean]] in the west to the [[Red Sea]] in the east, in a belt several hundred to a thousand kilometers (c. 600 miles) wide. It covers an area of {{convert|3,053,200|km2|sqmi|-1|sp=us}}.

Representing a climatic and ecological [[ecotone|transition zone]] with [[Semi-arid climate#Hot semi-arid climates|hot semi-desert and steppe conditions]], the Sahel region borders the [[Tropical savanna climate|more humid]] [[Sudanian savanna]]s to its south and the [[Desert climate|dry]] [[Sahara]] desert to the north.  This [[Ecoregion#Terrestrial|ecoregion]] is also called the '''Sahelian ''[[Acacia]]'' [[savanna]]''' in honour of its most prominent and very drought tolerant genus of tree.<ref name="wwf">{{WWF ecoregion | name = Sahelian Acacia savanna | id=at0713 | access-date = 2009-12-07 }}</ref>

The topography of the Sahel is mainly flat; most of the region lies between {{convert|200|and|400|m|ft|sp=us}} in elevation. Several isolated plateaus and mountain ranges rise from the Sahel (e.g. [[Marrah Mountains]], [[Aïr Mountains]], [[Ennedi Plateau]]), but are designated as separate ecoregions because their flora and fauna are distinct from the surrounding lowlands (e.g. [[East Saharan montane xeric woodlands|East Saharan woodlands]]). Annual rainfall varies from around {{convert|abbr=on|100|-|200|mm|in|0}} in the north of the Sahel to around {{convert|abbr=on|700|-|1,000|mm|in|0}} in the south.<ref name="wwf"/>

===Flora and fauna===
The Sahel is mostly covered in grassland and savanna, with areas of woodland and shrubland. Grass cover is fairly continuous across the region, dominated by annual grass species such as ''[[Cenchrus biflorus]], [[Schoenefeldia gracilis]]'' and ''[[Aristida stipoides]]''. Species of [[acacia]] are the dominant trees, with ''[[Acacia tortilis]]'' the most common, along with ''[[Senegalia senegal]]'' and ''[[Senegalia laeta]]''. Other tree species include ''[[Adansonia digitata]]'', ''[[Commiphora africana]]'', ''[[Balanites aegyptiaca]]'', ''[[Faidherbia albida]]'', ''[[Borassus aethiopum]]'', ''[[Vitellaria paradoxa]]'', ''[[Olea europaea]]'', ''[[Arbutus unedo]]'', ''[[Phoenix canariensis]]'', ''[[Hyphaene compressa]]'', ''[[Cupressus sempervirens]]'', ''[[Quercus coccifera]]'', ''[[Quercus suber]]'', ''[[Pinus nigra]]'', ''[[Populus nigra]]'', ''[[Ceratonia siliqua]]'', ''[[Salix alba]]'', ''[[Afzelia africana]]'', ''[[Kigelia africana]]'', ''[[Sclerocarya birrea]]'', and ''[[Boscia senegalensis]]''. In the northern part of the Sahel, areas of desert shrub, including ''[[Panicum turgidum]]'' and ''[[Aristida sieberiana]]'', alternate with areas of grassland and savanna. During the long dry season, many trees lose their leaves and the predominantly annual grasses die.

The Sahel was formerly home to large populations of grazing mammals, including the [[scimitar oryx|scimitar-horned oryx]] ''(Oryx dammah)'', [[dama gazelle]] ''(Gazella dama)'', [[Dorcas gazelle]] ''(Gazella dorcas)'', [[red-fronted gazelle]] ''(Gazella rufifrons)'', the giant prehistoric buffalo ''([[Pelorovis]])'', and [[Bubal hartebeest]] ''(Alcelaphus buselaphus buselaphus)'', along with large predators, such as the [[African wild dog]] ''(Lycaon pictus)'', the [[Northwest African cheetah]] ''(Acinonyx jubatus hecki)'', the [[Northeast African cheetah]] ''(Acinonyx jubatus soemmeringii)'', and the [[lion]] ''(Panthera leo)''. The larger species have been greatly reduced in number by over-hunting and competition with livestock, and several species are [[vulnerable species|vulnerable]] (Dorcas gazelle, cheetah, lion and red-fronted gazelle), [[endangered species|endangered]] ([[Dama gazelle]] and [[African wild dog]]), or [[extinction|extinct]] (the Scimitar-horned oryx is probably [[extinct in the wild]], and both ''[[Pelorovis]]'' and the Bubal hartebeest are now extinct).

The seasonal wetlands of the Sahel are important for [[migratory bird]]s moving within Africa and on the [[African-Eurasian flyways]].<ref name="wwf"/>

=== Climate ===
{{more citations needed section |date=April 2025}}
[[File:Acacia Trees (24227057806).jpg|thumb|[[Ennedi Plateau]] is located at the border of the Sahara and the Sahel]]
[[File:Seasonal westafrica rainfall mean 20070501 20070930.gif|thumb|right|10 year average precipitation during the summer rainy season (May - September) in the Sahel and adjacent regions]]
The Sahel has a [[hot semi-arid climate]] ([[Köppen climate classification]] ''BSh''). The climate is typically hot, sunny, dry and somewhat windy all year long. The Sahel's climate is similar to, but less extreme than, the climate of the [[Sahara desert]] located just to the north.

The Sahel mainly receives a low to very low amount of precipitation annually. The steppe has a very long, prevailing dry season and a short rainy season. The precipitation is also extremely irregular, and varies considerably from season to season. Most of the rain usually falls during four to six months in the middle of the year, while the other months may remain absolutely dry. The interior of the Sahel region generally receives between 200&nbsp;mm and 700&nbsp;mm of rain yearly. A system of subdivisions often adopted for the Sahelian climate based on annual rainfall is as follows: the Saharan-Sahelian climate, with mean annual precipitation between around 100 and 200&nbsp;mm (such as [[Khartoum]], Sudan), the strict Sahelian climate, with mean annual precipitation between around 200 and 700&nbsp;mm (such as [[Niamey]], Niger) and the Sahelian-Sudanese climate, with mean annual precipitation between around 700 and 900&nbsp;mm (such as [[Ouagadougou]], Burkina Faso). The [[relative humidity]] in the steppe is low to very low, often between 10% and 25% during the dry season and between 25% and 75% during the rainy season. The least humid places have a relative humidity under 35%.{{Citation needed|date=August 2022}} Annual rain levels were measured to fall between 20-40% in a span of two decades from 1931-1960 and 1968-1990; the levels recovered slightly in the mid-1990s in some areas, especially in central and eastern areas as far as Senegal.{{sfn|Khatim Kherraz|Nabil Ben Khatra|2019|p=8}}

The Sahel is characterized by constant, intense heat, with an unvarying temperature. The Sahel rarely experiences cold temperatures. During the hottest period, the average high temperatures are generally between {{convert|36|and|42|°C}} (and even more in the hottest regions), often for more than three months, while the average low temperatures are around {{convert|25|to|31|°C}}. During the "coldest period", the average high temperatures are between {{convert|27|and|33|°C}} and the average low temperatures are between {{convert|15|and|21|°C}}.<ref>{{Cite web |title=Global Surface Temperature  |url=https://climate.nasa.gov/vital-signs/global-temperature |website= Global Climate Change: Vital Signs of the Planet |publisher=[[NASA]]  |access-date=26 August 2022 }}</ref> Everywhere in the Sahel, the average mean temperature is over {{convert|18|°C}}.

The Sahel has a high to very high [[sunshine duration]] year-round, between 2,400 hours (about 55% of the daylight hours) and 3,600 hours (more than 80% of the daylight hours). The sunshine duration in the Sahel approaches desert levels, and is comparable to that in the [[Arabian Desert]], for example, even though the Sahel is only a steppe and not a desert. The [[cloud cover]] is low to very low. For example, [[Niamey]], Niger has 3,082 hours of bright sunshine; [[Gao]], Mali has near 3,385 hours of sunshine; [[Timbuktu]], Mali has 3,409 sunny hours, and [[N'Djamena]], Chad has 3,205 hours of sunlight.<ref>{{Cite web|url=http://www.niamey.climatemps.com/|title=Niamey Climate Niamey Temperatures Niamey Weather Averages|website=www.niamey.climatemps.com}}</ref><ref>{{Cite web|url=http://www.timbuktu.climatemps.com/|title=Timbuktu Climate Timbuktu Temperatures Timbuktu Weather Averages|website=www.timbuktu.climatemps.com}}</ref><ref>{{Cite web|url=http://www.gao.climatemps.com/|title=Gao Climate Gao Temperatures Gao Weather Averages|website=www.gao.climatemps.com}}</ref><ref>{{Cite web|url=http://www.n-djamena.climatemps.com/|title=N'Djamena Climate N'Djamena Temperatures N'Djamena Weather Averages|website=www.n-djamena.climatemps.com}}</ref>

===Recent droughts===
{{Further|Sahel drought}}
For hundreds of years, the Sahel region has experienced frequent droughts and [[megadrought]]s. One megadrought lasted from 1450 to 1700, 250 years.<ref>{{cite magazine|last=Brahic|first=Catherine|title=Africa trapped in mega-drought cycle|url=https://www.newscientist.com/article/dn16967-africa-trapped-in-megadrought-cycle.html|magazine=New Scientist|access-date=17 December 2012}}</ref> There was a major drought in the Sahel in 1914 caused by annual rains far below average, leading to large-scale famine. From 1951 to 2004, the Sahel experienced some of the most consistent and severe droughts in Africa.<ref>{{cite web|last=Scholl|first=Adam|title=Map Room: Hidden Waters|url=http://www.worldpolicy.org/journal/winter2012/map-room|publisher=World Policy Journal|access-date=17 December 2012|archive-date=30 October 2021|archive-url=https://web.archive.org/web/20211030012853/http://worldpolicy.org/2013/09/12/map-room-anonymous/|url-status=dead}}</ref> The 1960s saw a large increase in rainfall in the region, making the northern drier region more accessible. There was a push, supported by governments, for people to move northwards. When the long drought period from 1968 through 1974 began, grazing quickly became unsustainable and large-scale denuding of the terrain followed. Like the drought in 1914, this led to a large-scale famine, but this time somewhat tempered by international visibility and an outpouring of aid. This catastrophe led to the founding of the [[International Fund for Agricultural Development]].

====2010 drought====
{{Main|2010 Sahel famine}} 
Between June and August 2010, famine struck the Sahel.<ref>{{cite news|url=http://www.channel4.com/news/articles/world/africa/drought+threatens+african+humanitarian+crisis/3697427 |title=Drought threatens African humanitarian crisis – Channel 4 News |publisher=Channel4.com |date=2010-07-01 |access-date=2010-07-28}}</ref> Niger's crops failed to mature in the heat, 350,000 faced starvation, and 1,200,000 were at risk of famine.<ref>{{cite news| url=https://www.theguardian.com/world/2010/jun/21/millions-face-starvation-west-africa | location=London | work=The Guardian | title=Millions face starvation in west Africa, warn aid agencies | first=Henry | last=Foy | date=2010-06-21}}</ref> In Chad the temperature reached {{convert|47.6|°C|°F|1|abbr=on}} on 22 June in [[Faya-Largeau]], breaking a record set in 1961 at the same location. Niger tied its highest temperature record set in 1998, also on 22 June, at 47.1&nbsp;°C in [[Bilma]]. That record was broken the next day, when Bilma hit {{convert|48.2|°C|°F|1|abbr=on}}. The hottest temperature recorded in Sudan was reached on 25 June, at {{convert|49.6|°C|°F|1|abbr=on}} in [[Dongola]], breaking a record set in 1987.<ref name="MastersNOAA">{{cite web|last=Masters|first=Jeff|title=NOAA: June 2010 the globe's 4th consecutive warmest month on record|url=http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1544|work=Weather Underground|publisher=Jeff Masters' WonderBlog|access-date=21 July 2010|url-status=dead|archive-url=https://web.archive.org/web/20100719104107/http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1544|archive-date=19 July 2010}}</ref> Niger reported on 14 July that [[diarrhoea]], starvation, [[gastroenteritis]], [[malnutrition]] and [[respiratory diseases]] had sickened or killed many children. The new [[military junta]] appealed for international food aid and took serious steps to call on overseas help.<ref>{{cite news|url=http://www.france24.com/en/20100625-reporters-niger-famine-horizon-harvests-sahara-junta-coup-appeal-international-aid-mamadou-tandja |title=Niger: famine on the horizon? |publisher=France 24 |date=2010-07-14 |access-date=2012-10-25}}</ref> On 26 July, the heat reached near-record levels over Chad and Niger,<ref name="underground.com">{{cite web |url=http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1516 |title=wonder Blog: Weather Underground |publisher=Wonder-ground.com |access-date=2010-07-28 |url-status=dead |archive-url=https://web.archive.org/web/20100627220406/http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1516 |archive-date=2010-06-27 }}</ref> and in northern Niger about 20 people reportedly died of dehydration by 27 July.{{Citation needed|date=October 2022}}

===Desertification and soil loss===
[[File:Camels in Chad.png|thumb|right|[[Camel]]s at a [[watering hole]] in the [[Semi-arid climate#Hot semi-arid climates|semi-arid]] Sahel in [[Chad]]]]
The Sahel region faces environmental issues that are contributing to [[global warming]]. If the change in climate in the Sahel region "is not slowed-down and [[Desertification in Africa|desertification]] possibly reversed through sustainable practices and any form of [[reforestation]], it is only a matter of time before countries like Niger lose their entire landmass to desert due to unchecked unsustainable human practices.<ref name="ReferenceA">{{cite web |url=https://www.morganorioha.com/wp-content/uploads/2018/09/Managing-Climate-Reality-in-Sub-Sahara_Africa-2.pdf |title=Managing Climate Reality in Sub-Sahara Africa |publisher= Morganorioha.com |date=2018 |author=Orioha, M. K. |access-date=January 19, 2019}}</ref>{{rp|9}} [[Overexploitation|Over-farming]], over-grazing, [[over-population]] of marginal lands, and natural [[soil erosion]] have caused serious [[desertification]] of the region.<ref>{{Cite web|url=http://desertificationb.tripod.com/id3.html|title=Causes and Effects of Desertification|access-date=2010-06-19|archive-date=2013-12-02|archive-url=https://web.archive.org/web/20131202224726/http://desertificationb.tripod.com/id3.html|url-status=dead}}</ref><ref>Schmidt, Laurie J. (18 May 2001). [http://earthobservatory.nasa.gov/Features/DustBowl/ "From the Dust Bowl to the Sahel"]. NASA.</ref> This has affected shelter construction, making it necessary to change the used materials. The Woodless Construction project was introduced in Sahel in 1980 by the Development Workshop, achieving since then a high social impact in the region.<ref>{{Cite web|url=http://sior.ub.edu/jspui/cris/socialimpact/socialimpact00509|title=Training and employment of locals. [Social Impact]. WConstruction. The promotion of Woodless Construction in West Africa (1980–2017).|website=SIOR, Social Impact Open Repository}}</ref> A major initiative to combat desertification in the Sahel region via reforestation and other interventions is the [[Great Green Wall (Africa)|Great Green Wall]].

Major [[dust storm]]s are a frequent occurrence as well. During November 2004, a number of major dust storms hit [[Chad]], originating in the [[Bodélé Depression]].<ref>{{cite web|title=Dust Storm in the Bodele Depression|date = December 2004|url=http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=14230|publisher=NASA|access-date=19 June 2010}}</ref> This is a common area for dust storms, occurring on average on 100 days every year.<ref>{{Cite web |last=Di Liberto |first=John |date=13 Jul 2018 |title=Dust from the Sahara Desert stretches across the tropical Atlantic Ocean in late June/early July 2018 |url=https://www.climate.gov/news-features/event-tracker/dust-sahara-desert-stretches-across-tropical-atlantic-ocean-late |url-status=live |archive-url=https://web.archive.org/web/20230802170246/https://www.climate.gov/news-features/event-tracker/dust-sahara-desert-stretches-across-tropical-atlantic-ocean-late |archive-date=2 Aug 2023 |access-date=26 Feb 2024 |website=climate.gov}}</ref>
[[File:Village Telly in Mali.jpg|thumb|Sahel region of [[Mali]]]]
On 23 March 2010, a major sandstorm hit Mauritania, Senegal, [[The Gambia]], [[Guinea-Bissau]], [[Guinea]], and inland [[Sierra Leone]]. Another struck in southern [[Algeria]], inland Mauritania, Mali and northern [[Ivory Coast]]<ref>{{Cite web|url=http://www.eosnap.com/?tag=sand-storm|title=Earth Snapshot • Sand Storm|access-date=2010-06-18|archive-date=2011-04-29|archive-url=https://web.archive.org/web/20110429234702/http://www.eosnap.com/?tag=sand-storm|url-status=dead}}</ref> at the same time.

Following the drought period of the 1970s and 1980, however, the Sahel began to experience increased rainfall.<ref>{{cite web |url=https://adaptation.ei.columbia.edu/content/re-greening-sahel |title=Re-Greening of the Sahel |author= |date= |publisher=Columbia University |accessdate=October 27, 2024}}</ref> This may be due to [[global warming]], which can cause changes that may result in changes in large-scale weather patterns, such as increased stronger monsoons, in turn caused by a warmer Atlantic Ocean.<ref>{{cite journal |last1=Pausata |first1=Francesco S.R. <!--et al--> |date=March 2020 |title=The Greening of the Sahara: Past Changes and Future Implications |url=https://www.sciencedirect.com/science/article/pii/S2590332220301007 |journal=One Earth |volume=2 |issue=3 |pages=235–250 |doi=10.1016/j.oneear.2020.03.002 |bibcode=2020OEart...2..235P |access-date=October 26, 2024}}</ref> Warming of the [[Mediterranean Sea]] may also be a factor.<ref>{{cite journal |last1=Biasutti |first1=Michela |date=27 June 2016 |title=What brings rain to the Sahel? |url=https://www.nature.com/articles/nclimate3080 |journal=Nature Climate Change |volume=6 |issue= 10|pages=897–898 |doi=10.1038/nclimate3080 |bibcode=2016NatCC...6..897B |access-date=October 26, 2024}}</ref>

===Protected areas===
Protected areas in the Sahel include [[Ferlo Nord Wildlife Reserve]] in Senegal, [[Sylvo-Pastoral and Partial Faunal Reserve of the Sahel]] in Burkina Faso, [[Ansonga-Ménake Faunal Reserve]] in Mali, [[Tadres Reserve]] in Niger, and [[Waza National Park]] in Cameroon.<ref>{{Cite web|date=2022-02-07|title=SERIES 2 {{!}} Rising tensions in the Sahel|url=https://theinformant247.com/series-2-rising-tensions-in-the-sahel/|access-date=2022-02-16|website=The Informant247|language=en-US}}</ref>