Lake 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 Human activities in the lake's watershed require that increasing amounts of water be withdrawn for dam construction, irrigation activities and other purposes.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 patterns."

www.unep.org/vitalwater/27.htm

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).

Governments dependent on Lake Chad water have appealed for international support to replenish the lake. The Science-in-Africa web site (Africa's first online science magazine) reported that "The project -- in English 'Lake Chad Replenishment Project' -- would entail damming the Oubangui River at Palambo in the Central African Republic (CAR) and channeling some of its water through a navigable canal to Lake Chad. It is a large-scale project which requires heavy resources," according to Niger's Minister of Environmental and Hydraulic Affairs, Adamou Namata. At least there is a desire on the part of some governments in the Lake Chad basin to "Save the Lake" (www.scienceinafrica.co.za/2003/march/chad.htm).

www.worldlakes.org/lakedetails.asp?lakeid=8357

The Aral Sea: A disappearing sea in Central Asia

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.

An Uzbek Government poster display showing the declining levels of the Aral Sea over the last several decades. Photo by M.H. Glantz, taken in Nukus, Karakalpakstan, Uzbekistan in September 1995.

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.

Concluding Thought

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