Lake Chad and the Aral Sea: A Sad Tale of Two Lakes
Michael H. Glantz
9 September 2004
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 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require that increasing amounts of water be withdrawn for dam construction,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.
Clearly, the lake's fishermen have been greatly affected by the shrinkage of the lake. However, some farmers have benefited because the seabed where the lake had receded has favorable soil moisture for agricultural production and livestock rearing. Pastoralists have been forced due to the drying out of the lake to move their herds to the wetter south, putting them and their herds in conflict with farmers. There are serious environmental problems to contend with: soil salinization, invasion of unwanted vegetative species, increasing water demands for irrigation and loss of fisheries, along with an increase in poverty.
The continued existence
of the lake even into the not-so-distant future is not assured. Population
pressures for water, land and food will continue to mount. Water in the
region will increasingly become even more scarce than it is at present.
And, the regional impacts of global warming of the atmosphere have as
yet to be identified, although many researchers believe that the first
signs of global warming have already appeared in the area surrounding
Lake Chad. A recent report on climate change and the hydrologic cycle
suggested, "Of all the major basins in the world, probably Lake Chad
has been affected most by climate change" (www.fao.org/docrep/W5183E/w5183e04.htm).
Thousands of miles away in Central Asia, it is possible to see the harbinger of Lake Chad's future, if no changes in trends in water use occur. The Aral Sea is sandwiched between two deserts. Forty years ago, the Aral was, ironically for this comparison, the fourth-largest inland body of water in the world. Today, after only four decades of accelerated human exploitation of the Aral Basin's water resources, the sea (really a lake without an outlet to the world's oceans) is well in its way to extinction. Two countries share the sea, Uzbekistan and Kazakhstan, both of which are downstream from the rivers. The Aral Sea basin contains parts of several countries through which Central Asia's two major rivers flow, the Amudarya and the Syrdarya. These two rivers are the lifelines for water inflow to the Aral Sea. The upstream states through which the rivers flow include Tajikistan, Kyrgyzstan and Afghanistan. Turkmenistan has a major canal that withdraws a disproportionate share of Amudarya water before it reaches Uzbekistan's irrigation diversion canals and farmlands.
As with Lake Chad, human activities in the region had expanded sharply since 1960, and the demands on streamflow diversions from these rivers intensified. It has intensified to the extent that, since the late 1970s, there have been many years when the flow of one or both of these rivers never made it to the sea. As a result, the level of the Aral declined steadily since then. The region had been the major cotton-producing region for the Soviet Union and, after the breakup of the USSR, cotton production continued to be a mainstay of Uzbekistan's economy.
The Aral Sea level has dropped about 20m since 1960, primarily as a result of increased diversions from the Amudarya and Syrdarya rivers for irrigation purposes.
The influence of human activities in the Aral, unlike the situation with Lake Chad, has been the major reason behind the declining sea level over the part 40 years or so. The water of the two major rivers that feed the Aral Sea has increasingly been diverted away from the sea are directed toward the desert soils primarily for cotton production. Combining this reduction of flow into the sea with high evaporation rates and low precipitation levels over the sea, the level of the sea had to drop.
Kazakhstan's leaders decided to save the northern part of the Aral, called the Little Aral. The larger Aral to the south has since divided into eastern and western parts with the shallow eastern part on the edge of complete desiccation. The lucrative commercial fishing industry that once supported 60,000 people had been brought to a halt, as the quality and quantity of the seawater changed for the worse and the commercial fish populations disappeared. Poverty and out migration increased, as did illness and desertification processes in the region surrounding the sea. Salinity of the irrigated soils has been a major problem leading at first to an increase in the amount of water needed to flush the salts from the soil and in many cases to land abandonment followed by an increase in the number of dust storms.
The demise of these two lakes in different parts of the globe can be very instructive. One of the lakes has pretty much disappeared as a result of human factors (the Aral) and the other is disappearing as the combined result of overuse of river water and of a drier climate regime. While it is not too late to correct the situation in the Lake Chad region, it is likely too late for the Aral as the economy of Uzbekistan is over dependent on river diversions for cotton production. Many of the processes in both lake regions involving humans have been similar: out migration, land abandonment, loss of wetlands, loss of flora and fauna, desertification, invasion of unwanted species, loss of livelihoods, increases in irrigation, and so forth.
If they have not already done so, it may be wise for the managers of the Lake Chad basin to revisit the recent demise of the Aral Sea in order to gain a better glimpse of where their lake ecosystem and people dependent on it are headed, under a "business as usual scenario," that is, if there is no change in the direction of current water use decisions.
These two lake situations reinforce my belief that when it comes to environmental changes the future for some places already exists elsewhere on the globe. The Aral scenario seems to be Lake Chad's future. The big question that demands an honest answer is this: Do the governments associated with the Lake Chad basin's water supply and demand situation care enough to save the Lake?
--Michael H. Glantz
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