Lake Chad, once one of the African continent's largest bodies of freshwater, has dramatically decreased in size due to climate change andhuman demand for water. Once a great lake close in surface area to NorthAmerica's Lake Erie, Lake Chad is now a ghost of its former self.According to a study by University of Wisconsin-Madison researchers,working with NASA's Earth Observing System program, the lake is now1/20th of the size it was 35 years ago.
Found at the intersection of four different countries in West Africa(Chad, Niger, Nigeria, and Cameroon), Lake Chad has been the source ofwater for massive irrigation projects. In addition, the region hassuffered from an increasingly dry climate, experiencing a significantdecline in rainfall since the early 1960s.
The most dramatic decrease in the size of the lake is shown in thefifteen years between January 1973 and January 1987. Beginning in 1983the amount of water used for irrigation began to increase. Ultimately,between 1983 and 1994, the amount of water diverted for purposes ofirrigation quadrupled from the amount used in the previous 25 years. Thered color denotes vegetation on the lake bed and the ripples on thewestern edge of the lake denote sand dunes formed by the wind.
The bottom picture is a composite of Landsat-7 images from November 2000 to February2001 showing the present stage of Lake Chad. The small patch of blue thatis now the lake stands in stark contrast to the wide swath of the oldlake bed (shown in green, indicating vegetation).
For more information, see: Africa'S Lake Chad Shrinks by 20 Times Due to Irrigation Demands, Climate Change
References & Resources
Images courtesy NASA GSFC Scientific Visualization Studio and Landsat 7 Project Science Office.
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