Water And Oceanography

What’s Causing Lake Chad to Shrink



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Lake Chad, once the sixth largest lake in the world, and Africa’s largest inland lake, has long been a vital part of the ecology and economies of its four bordering nations (Chad, Niger, Nigeria, and Cameroon). Some 20 to 30 million people in the surrounding region depend on the lake for fishing as well as their primary source of potable water and irrigation for farming and livestock. But like a number of other lakes throughout the world (e.g., the Aral Sea in Asia), Lake Chad has been drying up over the past 40 years.

In 1963, the lake covered some 9,700 square miles, but since then it has shrunk to about one-twentieth that size, according to Michael Coe and Jonathan Foley of the University of Wisconsin-Madison (www.sciencedaily.com). NASA forecasts predict that the lake could disappear entirely by about 2030 if it continues to recede at current rates (www.fao.org). Though it has experienced repeated cyclical periods of expansion and shrinking over its approximately 20,000-year-long history, many local fishermen and farmers consider the recent dramatic changes far greater than past declines (news.nationalgeographic.com).

Something more than the normal cyclical variations in rainfall and usage seems to be at work, and the prime suspect appears to be human activities. Global warming is already having profound effects on many ecosystems, particularly in the developing world, including more and longer lasting droughts in places like Africa and Australia, along with the melting of polar ice caps and mountain glaciers. While some island nations face annihilation from rising sea levels, areas dependent on monsoon rains and mountain glaciers for vital water sources, are facing famine.

Climate change has set off a devastating chain of events that affect the Lake Chad region in several ways. Severe droughts, starting in the late 1960s, have advanced the desert deep into the sub-Saharan region.. The lake’s waters come from the Chairi and Logone rivers and the summer monsoon rains. The lack of rain has diminished both these sources, while increasing the local population’s dependency on the lake as their primary water source (news.nationalgeographic.com).

The desertification process reduces the vegetation available for livestock, resulting in overgrazing of the surrounding savanna. This, in turn, intensifies the desertification, according to Foley, by reducing “the ecosystem’s ability to recycle moisture back into the atmosphere.” Declining water levels have also reduced the fish populations by about 60%. Unfortunately, growing population pressures and irrigation demands are likely to worsen the situation (www.sciencedaily.com).

According to the UN’s Food and Agricultural Organization, 1.2 billion people now have inadequate access to water, and by 2025, some two-thirds of the world population could be facing water shortage (www.fao.org). Water is likely to be for the 21st century what oil has been for much of recent history, as shrinking supplies lead to millions of displaced peoples and global conflict over access to the precious resource.

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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://www.sciencedaily.com/releases/2001/02/010228080245.htm
  • InfoBoxCallToAction ActionArrowhttp://www.fao.org/news/story/en/item/36126/icode/
  • InfoBoxCallToAction ActionArrowhttp://news.nationalgeographic.com/news/2001/04/0426_lakechadshrinks.html
  • InfoBoxCallToAction ActionArrowhttp://news.nationalgeographic.com/news/2001/04/0426_lakechadshrinks.html
  • InfoBoxCallToAction ActionArrowhttp://www.sciencedaily.com/releases/2001/02/010228080245.htm
  • InfoBoxCallToAction ActionArrowhttp://www.fao.org/news/story/en/item/36126/icode/