 Lake Chad in a 2001 satellite image, with the actual lake in blue, and vegetation on top of the old lake bed in green. Above that, the changes from 1973 to 1997 are shown. Lake Chad (in French: Lac Tchad) is a large, shallow lake in Africa. It is economically very important, providing water to more than 20 million people living in the countries which surround it - Chad, Cameroon, Niger and Nigeria. It is located mainly in the far west of Chad, bordering on northeastern Nigeria. The lake possesses many small islands and mudbanks, and its shorelines are largely comprised of marshes. Because it is very shallow - only 7 metres at its deepest - its area is particularly sensitive to small changes in average depth, and it consequently also shows seasonal fluctuations in size. It has no apparent outlet but its waters percolate into the Soro and Bodele depressions.
The lake is believed to be a remnant of a former inland sea which is estimated to have covered an area of 300,000 km² 6,000 years ago. It was one of the largest lakes in the world when first surveyed by Europeans in 1823, but it has shrunk considerably since then. Climate change and increased demands on the lake's water have accelerated its shrinkage over the past 40 years. In the 1960s it had an area of more than 26,000 km², making it the fourth largest lake in Africa. By 2000 its extent had fallen to less than 1,500 km². This is due to reduced rainfall combined with greatly increased amounts of irrigation water being drawn from the lake and the rivers which feed it, the largest being the Chari/Logon system, which originates in the mountains of the Central African Republic. It seems likely that the lake will shrink further and perhaps even disappear altogether in the course of the 21st century.
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