http://www.fragilecologies.com/sep09_04.htmlLake Chad and the Aral Sea: A sad tale of two lakes
When I studied African politics about 40 years ago with visiting Lincoln University professor John Marcum at the University of Pennsylvania, Lake Chad was immense in surface area. It was the fourth largest inland water body on the African continent. The lake's surface area in 1963 was about 25000 square kilometers. The lake is very shallow, on the order of 5 to 8 m deep. Its waters provided livelihoods for fishermen as well as for settlements, cultivators and herders. The Chari and the Longone rivers are the major ones that feed the lake, a land-locked lake with no outlet to the oceans.
"The lake is shared by Cameroon, Chad, Nigeria and Niger which, along with CAR (Central African Republic), make up the Lake Chad Basin Commission (LCBC), whose name in French is the Commission du Bassin du Lac Tchad (CBLT). Its basin extends over 967,000 sq km and is home to about 20 million people, according to LCBC. These include 11.7 million in Nigeria, 5.0 million in Chad, 2.5 million in Cameroon, 634,000 in the CAR and 193,000 in Niger" (www.irinnews.org; March 21, 2003).
The Lake Chad Basin Commission is an organization designed to manage the basin and to resolve disputes that might arise over the lake and its resources.
Being on the fringe of the Sahara, high temperatures assure that evaporation rates of the lake's water would be high (estimated at 2000mm/year). Rainfall (about 1500mm/year in the south and 100mm in the north of the basin) has been another source of its water.
Today, the surface area of the lake barely reaches 1350 square kilometers. According to a BBC news report (March 24, 2004), "Nigeria's president has warned that Lake Chad will soon disappear unless immediate action is taken." Once the fourth-largest African lake (and the sixth largest lake in the world), today, is on its way to extinction.
The levels of the lake have fluctuated over decades, centuries and millennia, responding to changes in the global temperature and regional precipitation. There was a time in history when Lake Chad was so huge that contemporary historians refer to it as Mega-Chad. At other times it may have even come close to disappearing. But these changes have more or less been on long time scales and were clearly caused by natural changes in the climate system. All that has changed in the modern era. Human activities in the lake's watershed require that increasing amounts of water be withdrawn for dam construction, irrigation activities and other purposes. At the same time as the population's demand for water is increasing, the climate in the region has been changing in ways that have apparently not been seen in a thousand years or more.
The recent drying out of the lake apparently started in the 1960s and has continued for almost two decades. This drying out was primarily because of severe meteorological drought (that is, reduced rainfall for well over a decade) and continued high temperatures both of which are natural factors. In fact the surface area of the lake declined by more than 20% during West Africa's disastrous Sahelian drought from 1968-73. By the 1980s and 1990s, however, water from the rivers that flow into the lake was being diverted in increasing amounts for irrigation purposes. It is estimated that about one-third of the streamflow today is diverted from the Chari River before its flow reaches Lake Chad.
Diversion of streamflow had been at a relatively low level, until the late 1970s when Lake Chad basin countries began to sharply intensify their food and fiber (e.g., cash crop) production efforts. According to UNEP GRID, "between 1953 and 1979, irrigation had only a modest impact on the Lake Chad ecosystem. Between 1983 and 1994, however, irrigation water use increased four-fold. About 50% of the decrease in the lake's size since the 1960s is attributed to human water use, with the remainder attributed to shifting climate pattern
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