Water And Oceanography

What is Causing Lake Chad and other Lakes to Shrink



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In this “climate” of the global warming phenomena, shrinking lakes appear to be proof that global warming disrupts and negatively impacts water ecosystems. But the full story involves Mother Nature’s cycles of balance and change counterbalanced by many intrusive, human activities. In particular, humanity’s neglect, misunderstanding and mismanagement of water resources are prime reasons why our water worlds, represented by diminishing lakes, are in crisis.

The shrinking Lake Chad in northern central Africa has attracted world attention, extensive research and documentation but not world solutions. Solutions are difficult to define because the causes of the lake’s current state are ill defined. 

To understand the condition of Lake Chad, some “setting” details should be identified.  Lake Chad is in the Sahel, a sprawling savanna bordered by the rain forests of the African west coast and the Sahara desert to the north. Chad, Niger, Nigeria, and Cameroon are neighbouring countries dependent on Lake Chad as a water resource. Monsoon rains usually fall from June to August.

Those who support recent causes for the shrinking of Lake Chad blame an overuse of irrigation systems between 1983 and 1994 and the construction of hydro-electric power plants. But these contenders ignore the fact that just prior, the 1970’s were drought years making “the northern half of the lake (Northern Basin) completely dry and turned the Southern Basin into a densely vegetated area with scattered swamps and open pools.” International Lake Environment Committee The annual monsoon rains failed, so people depended more on Lake Chad for water. The increase of irrigation systems and hydro-electric plants were short term reactions to the current drought status quo of Nature. Instead of respecting the drought cycle, humanity challenged it. Humanity “panicked” into a solution creating more problems. 

Others support the theory that the environmental pressures of a significant increase in population in the area of Lake Chad caused the shrinking. Approximately 11 million people live in the basin but “An estimated 20 million people rely on Lake Chad/ Hadejia-Nguru for their economic activities, a figure that is projected to rise to 35 million by the year 2020 (World Bank 2000).”   (Lake Chad flooded savannah

Population growth brings with it attendant demands and problems. And because different countries depend on Lake Chad, consensus on water management strategies is difficult to attain, further avoiding a solution. The Lake Chad Basin Commission was formed in 1964 to regulate and plan uses of the water and natural resources within the Lake Chad Basin. Cameroon, Chad, Niger, and Nigeria were founding members while the Central African Republic was admitted in 1994 and Sudan was admitted in 2000.  (Shrinking African Lake Offers Lesson on Finite Resources) Humanity’s lifestyle has disrupted and overturned the ecosystem, the natural dynamics of the Lake Chad region.

However, history shows that this shrinking phenomena is not unique to recent years. Some 50,000 years ago, Paleo-Chad or Lake Megachad formed a freshwater inland sea covering nearly 2 million km2. Case Studies of Africa’s Changing Lakes

But the real surprise is that Chad was once one of 4 megalakes in the Sahara region thousands of years ago. “Lake Megafezzan was north of Lake Megachad in present day Libya, the Chotts Megalake was in present day northern Algeria and the Ahnot-Moyer Megalake in central Algeria.” The shrinking of Lake Chad cannot be blamed on anthropogenic CO2 - November 18, 2007. Only Lake Chad remains of the old giants.   

1963 may have been a high point in Lake Chad’s 20th century history, but it was not a high point in its global history. 1963 was a temporary hiatus before Lake Chad’s further decline “naturally”. Human activity merely exacerbated and certified the process.

Other shrinking lakes in the world present similar scenarios. In Uzbekistan and Kazakstan, the Aral Sea, an endheoric lake (a terminal lake with no outfall), has been impacted by the construction and use of the Karakum Canal. This is the largest and longest irrigation canal of the former Soviet Union, stretching 1300km westward from the Amu Dar'ya into the Kara-Kum Desert.

“With contraction, the sea's influence on climate has substantially diminished. Summers have become warmer, winters cooler, spring frosts later, and fall frosts earlier, the growing season has shortened, humidity has lowered.”  (Desiccation of the Aral Sea – Philip P. Mickin)

Further, salt and dust storms from the dried lake bed have reached l000 km to the southeast in the fertile Fergana Valley, in Georgia on the Black Sea coast, and even along the arctic shores. (op.cit.) In the past, the sea completely dried up and then returned. But human interference has complicated Nature’s process. Man’s needs complicate Nature’s needs.

Donting Lake, in the middle reaches of China’s Yangtse River could be one example of a lake shrinking primarily because of global warming. It was reported in November 2009 that continued years of drought upstream led to less than 10 percent of the average volume during the flood season. In the 1950s, about 150 billion cu. m. of water flowed from the Yangtze River into Dongting Lake each year. From 1990 to 1998, the annual flow into the lake was lowered to 88 billion cu. m. by the operation of the Three Gorges Reservoir.

Of further concern, the exposed lake bed is a conducive environment for rats and mice. When the Yangtse flooded in June 23, 2007, 2 billion rats were flushed out and raced for higher ground. Further, the rats ravaged about 1.6 million hectares of farmland crops. (China Daily “Shrinking major lake a victim of drought”) Man’s neglect and misunderstanding of water resources and Nature’s cycles could initiate plagues and a primary resource crisis.

What is causing Lake Chad and other lakes to shrink? The blame seems to sit squarely on the shoulders of humanity. As populations increase, so mismanagement, misinformation, misunderstanding and mistakes, often in the personas of self protection and greed, seem to be on the increase. Until humanity “tunes in” to Nature, Nature will tune us out.

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