Editing Lake Chad (section)

==Prehistory and history<span class="anchor" id="History"></span>==
[[File:Megatschad GIS.PNG|thumb|275px|Lake Chad in [[African humid period]] (blue) and in 20th century (green)|left]]
The [[Chad Basin]] was formed by the depression of the [[African Shield]].<ref name=w2/><ref name=hd3/><ref name=r4/> The floor of the basin is made of [[Precambrian]] bedrock covered by more than {{convert|3600|m|abbr=on}} of sedimentary deposits.<ref>{{cite book|last=Obaje|first=Nuhu George|title=Geology and Mineral Resources of Nigeria|url=https://books.google.com/books?id=U1VBp7aItooC&pg=PA69|access-date=2013-05-06|date=2009-08-12|publisher=Springer|isbn=978-3-540-92684-9|page=69}}</ref> For most of the [[Quaternary]], the basin had abundant water sources. Towards the end of this period the climate became drier. Around 20,000–40,000 years ago, [[eolianite]] sand dunes began to form in the north of the basin.<ref>{{cite book|last=Wright|first=J.B.|title=Geology and Mineral Resources of West Africa|url=https://books.google.com/books?id=YBDbdZrHosMC&pg=PA94|access-date=2013-05-06|date=1985-11-30|publisher=Springer|isbn=978-0-04-556001-1|page=95}}</ref> The area of Lake Chad experienced four heydays between 39,000 BC and 300 BC, leaving thick [[diatomaceous earth]] and [[lacustrine deposits]] in the strata. This has been called Mega-Chad. The maximum depth of Mega-Chad exceeds {{convert|180|m|ft|abbr=on}} and covers an area of approximately {{convert|400000|km2|sqmi|abbr=on}},<ref name=w2/> flowed into the [[Benue River]] through the [[Mayo Kébbi]], and finally flows into the [[Atlantic Ocean]] through the [[Niger River]].<ref>{{cite journal|last1=Leblanc|first1=M.|last2=Favreau|first2=G.|last3=Maley|first3=J.|last4=Nazoumou|first4=Y.|last5=Leduc|first5=C.|last6=Stagnitti|first6=F.|last7=van Oevelen|first7=P. J.|last8=Delclaux|first8=F.|last9=Lemoalle|first9=J.|year=2006|title=Reconstruction of Megalake Chad using Shuttle Radar Topographic Mission data|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=239|issue=1–2|pages=16–27|doi=10.1016/j.palaeo.2006.01.003|url=https://www.researchgate.net/publication/222672298|language=en|access-date=2023-06-13|archive-date=2023-06-13|archive-url=https://web.archive.org/web/20230613162944/https://www.researchgate.net/publication/222672298_Reconstruction_of_Megalake_Chad_using_Shuttle_Radar_Topographic_Mission_data}}</ref><ref>{{cite journal |author1=Mathieu Schuster |author2=Claude Roquin |author3=Philippe Duringer |author4=Michel Brunet |author5=Matthieu Caugy |author6=Michel Fontugne |author7=Hassan Taïsso Mackaye |author8=Patrick Vignaud |author9=Jean-François Ghienne |title=Holocene Lake Mega-Chad palaeoshorelines from space |journal=Quaternary Science Reviews |date=2005 |volume=24 |issue=16–17 |pages=1821–1827 |doi=10.1016/j.quascirev.2005.02.001 }}</ref>

The vast waters formed during the [[African humid period]] provided conditions for the emergence of lakeside fishermen's settlements, and the [[Nilo-Saharan]] ethnic group also migrated to Lake Chad during this period. Agriculture also emerged in the [[Sahel]] region at this time.<ref>{{cite book |author= Kevin Shillington |title=History of Africa|publisher=Macmillan Education UK |url=https://books.google.com/books?id=rxtHEAAAQBAJ|isbn=9781137524812 |pages=19–31 }}</ref> By 1800 BC, a [[pottery]] culture known as Gajiganna had emerged, initially as pastoralists, but, starting around 1500 BC, living in settled hamlets at the side of the lake.<ref>{{cite journal |last=Ogundiran |first=Akinwumi  |year=2005 |title=Four Millennia of Cultural History in Nigeria (ca. 2000 B.C.–A.D. 1900): Archaeological Perspectives |journal=Journal of World Prehistory |volume=19 |issue=2 |page=138 |doi=10.1007/s10963-006-9003-y}}</ref> The archaeological discovery revealed wild grasses, mostly of the tribe [[Paniceae]], and wild rice together with the earliest domesticated [[Pearl millet]] in the Lake Chad region, dating to 1200–1000 [[Radiocarbon calibration|cal BC]]. One of the oldest domesticated Pearl millet in West Africa was found in the Chad Basin, charred together with wild grasses, and their era can be traced back to 800–1000 cal BC.<ref>{{cite journal |author1=Marlies Klee |author2=Barbara Zach |title=The Exploitation of Wild and Domesticated Food Plants at Settlement Mounds in North-East Nigeria (1800 cal BC to Today) |journal=The Exploitation of Plant Resources in Ancient Africa |date=1999 |pages=81–88 |doi=10.1007/978-1-4757-6730-8_8|isbn=978-1-4419-3316-4 }}</ref>

Permanent villages were established to the south of the lake by 500 BC,<ref name=fzn1>{{cite book|last=Decorse|first=Christopher R.|title=West Africa During the Atlantic Slave Trade: Archaeological Perspectives|url=https://books.google.com/books?id=8Fcr1HSZXNgC&pg=PA103|access-date=2013-05-06|year=2001|publisher=Continuum International Publishing Group|isbn=978-0-7185-0247-8|page=103}}</ref> and major archaeological discoveries include the [[Sao civilization]].<ref name=w2/> According to the records of [[Claudius Ptolemy]] in the mid-2nd century AD, the Romans of the 1st century AD had already [[Romans in sub-Saharan Africa|come into contact]] with Lake Chad through their connections with Tunisia, [[Tripolitania]], and [[Fezzan]].<ref>{{Cite journal|last=Johnston|first=H. H.|date=1910|title=Lake Chad|journal=Nature|language=en|volume=84|issue=2130|pages=244–245|doi=10.1038/084244a0|bibcode=1910Natur..84..244J|s2cid=8682184|issn=1476-4687}}</ref> By the 5th century AD camels were being used for [[trans-Saharan trade]] via the Fezzan, or to the east via [[Darfur]].<ref name=eof1>{{cite book|last1=Appiah|first1=Kwame Anthony|last2=Gates|first2=Henry Louis Jr.|title=Encyclopaedia of Africa|url=https://books.google.com/books?id=A0XNvklcqbwC&pg=PA254|access-date=2013-05-06|year=2010|publisher=Oxford University Press|isbn=978-0-19-533770-9|page=254}}</ref> After the Arabs conquered North Africa during the 7th and 8th centuries, the Chad Basin became increasingly linked to the Muslim countries.<ref name=fzn1/> 

Trade and improved agricultural techniques enabled more sophisticated societies.<ref name=eof1/> Around 900 AD, the Kanem people who spoke the [[Kanuri language]] unified numerous nomadic tribes and established the [[Kanem Empire]] in the northeast of Lake Chad. At the beginning of the founding of the country, the Kanem people continued to live a nomadic life until the 11th century, when they were Islamized and settled in [[Njimi]]. Through [[trans-Saharan trade]], the power of the Kanem Empire reached its peak in the 13th century, but as the empire declined in the 14th century, its southwestern vassal state of [[Bornu Empire|Bornu]] began to rise, causing the power center of the empire to shift to Bornu around 1400. In the second half of the 16th century, the [[Bornu Empire]] began importing firearms from North Africa, consolidating its military hegemony. The Bornu Empire declined in the 18th century, and later lost its western region to the [[Sokoto Caliphate]] during the early 19th century. It was later colonised by European powers in the 20th century.<ref>{{cite book |author= Kevin Shillington |title=History of Africa |publisher=Macmillan Education UK |url=https://books.google.com/books?id=rxtHEAAAQBAJ|isbn=9781137524812 |pages=101-103+188-190+249-256 }}</ref>

Following the growing interest in Africa among European academic and business communities, the Lake Chad area was extensively described by Europeans in the 19th century. Three scientific expeditions were conducted between 1898 and 1909.<ref name=w2/> During the [[Berlin Conference]] in 1884–1885, Africa was divided between the European colonial powers. By the second decade of the 20th century, Lake Chad had been colonized and occupied by [[British Empire|Britain]], [[French colonial empire|France]], and [[German colonial empire|Germany]], defining boundaries that are largely intact with the present [[Decolonisation of Africa|post-colonial states]].<ref>{{cite book|last=Harlow|first=Barbara|title=Colonialism|chapter-url=https://books.google.com/books?id=qFTHBoRvQbsC&pg=PA139|access-date=2013-05-06|year=2003|publisher=ABC-CLIO|isbn=978-1-57607-335-3|chapter=Conference of Berlin (1884–1885)|page=139}}</ref><ref name=hea3>{{cite news |title=乍得湖：从"文明摇篮"到"死亡之心" |trans-title=Lake Chad: From "Cradle of Civilization" to "Heart of Death" |author1=熊正坤 |author2=张瑾 |url=http://www.chinawater.com.cn/newscenter/jlkt/202104/t20210408_763432.html |access-date=2024-01-01 |publisher=China Water Resources News |date=2021-04-08 |archive-date=1 January 2024 |archive-url=https://web.archive.org/web/20240101065102/http://www.chinawater.com.cn/newscenter/jlkt/202104/t20210408_763432.html |url-status=live }}</ref> At the beginning of independence, the countries surrounding Lake Chad not only had a poor economic foundation, but also had more complex ethnic, religious, and political conflicts. [[Nigeria]] and [[Niger]], which had just gained independence, experienced continuous coups, while Chad also experienced ongoing civil war. The inability of countries along the lake to consider the protection of Lake Chad has led to a series of environmental problems.<ref name=hea3/>