NEWSLETTER #38 - SOCIETY OF AFRICAN EARTH SCIENTISTS

 

Volume 10, Issue 1

January -March 2021


CONTENT
Chair's Foreword
Africa's Drying Lakes
Earth Science Events
References and selected reading

Chair's Foreword*

The Society is duty bound to ring its alarm bell at the creeping crisis in African water resources as represented by the drying of its major Lakes. This surreptitious occurrence has the potential to seriously destabilise parts of our continent, due to the emerging conflicts, population displacements and humanitarian crises brought about by the disappearance of these often vast bodies of water. Major reasons identified are climate change and human over utilisation of river and groundwater. Solutions and actions offered to redress this problem are  currently few and far between. 

Africa's Drying Lakes

One of the major crises that have crept up unnoticed and not spot-lighted in recent decades has been the gradual depletion of Africa's lakes due to both man-made and climatic factors. This is a continent-wide problem with many vital lakes disappearing and forcing displacements of urban and rural populations.  Ethiopia, for instance, is encountering huge changes in its level of water resources due to climate change and over-utilisation. Ethiopia has already lost Lake Ziway and its Haramaya Lake, one of its greatest lakes mainly due to over-utilisation. The lake once covered an area spanning 10 miles and was 30 feet in depth. Now nearby Harar City must seek an alternative source of clean water and its fishermen must move to a nearby lake [1]. 

   We can identify the Nile Valley River Basin as linked to the major continental Lakes in Africa. Many lakes fed by river systems throughout the entire continent are at risk as we see in the cited case of Ethiopia. For the purpose of this article, we assume as case studies and objects of  focus for our attention, the major lakes which are among the largest on the planet: Lake Chad, Lake Victoria and Lake Tanganyika.

Lake Chad

   The most shocking and alarming case of the major lakes suffering a rapid depletion of water in recent times is that of Lake Chad in the West Africa Sahel region which has shrunk in size by a staggering 90% in the 50 years from 1963 to 2017 [2]. 

Lake Chad changes from 1963 to 2017

   One project proposal for reversing the drying out given the name "Transaqua", dates back to the 1980s. It involves diverting the flow of the Congo River. However, no other remedial measures have been proposed  as an alternative to this method; which does not inspire the support of local people and will cost tens of billions of dollars to the surrounding affected countries [3].

   Various studies on Lake Chad agree that a severe depletion of lake water levels occurred during the droughts years of the 1970s and 1980s [4]. But Coe and Foley [5]  study the response of the lake to climate and water use practices between 1953 and 1979 and notice a four-fold increase in water use for irrigation from 1983 - 1994 in comparison with their  26 year period of study [6]. Okonkwo et al note the positive response of the lake water levels to increased rainfall  after the drought years of the 1970s and 1980s [7]; but significantly, Gao et al [8] sees the recovery of the lake due to increased rainfall to have been thwarted by the increased irrigation withdrawals noted earlier. Consequently, they see a full recovery of the lake by the natural means of increased precipitation  (rainfall) to be rendered unlikely without some form of inter-basin water transfer such as that suggested by the Transaqua project [9].

   The problem has been brought into sharper relief in recent years due to the drying of the lake exacerbating poverty in the region and making it more prone to the terrorism of Boko Haram and other groups who recruit youth made idle and jobless by the resulting loss of industry in the region as a result of the diminishing lake. There has been a loss of industries such as animal husbandry, farming and fishing as a result of the catastrophic loss of water resources. The situation is made even more dire by the fact that the implementation of any form of solution requires relative peace and security for personnel employed to operate safely.

Lake Victoria

   Lake Victoria is known to be the world's largest tropical freshwater lake and is the second largest  freshwater lake in the world after Lake Superior in North America. About 30 million people in Rwanda, Burundi, Uganda, Kenya and Tanzania rely on the lake for clean water, fishing, irrigation and electricity [10]. 

   Scientists report that the lake could dry up and disappear in the next 500 years. However,  there is no need for complacency, as the humanitarian and poverty effects of the loss of this water resource could be experienced by local people within a  few decades; and we have already watched as the decades passed us by whilst Lake Chad was diminished to one tenth of its size in just 50 years. Also one cannot calculate for unforeseen leaps in industrial water consumption  due to damming and hydropower projects, irrigation and cash crops production,  etc. Studies have also shown that water levels in the lake may be sensitive to small decreases in rainfall in coming years. Climate warming is increasing in the region, suggesting the risk of reducing rainfall rates in the future [11].

Lake Tanganyika

   Lake Tanganyika is the world's second deepest lake at a depth of 1,470 m. It drains a watershed that includes much of central South East Africa. A study of the lake by Ivory et al [12]  highlights the role of vegetation structure in directly driving the intensity of weathering and erosion over long time scales. This would appear to suggest that maintaining vegetation structure near bodies of water such as lakes must form part of the strategy to maintain these precious African water resources.

Earth Science Events

November  4-5, 2021

International Conference on Ecological Geology and Earth Science ALSO

Earth Science and Climate Change ALSO Rock Mechanics, Geological Ecology and Environmental Engineering Conferences

VISION: Bringing together scientists, researchers and scholars to share experiences, knowledge and research on the subject areas.

VENUE: Capetown, South Africa.

References 

[1] Tollera, M.T., Climate change, over-utilisation dry up  Ethiopian lakes, Down to Earth, 29 May 2018.

[2] Usigbe, L, Drying Lake Chad Gives Rise to Crisis, Africa Renewal, United Nations, December 2019.

[3] Ross, W.,  Lake Chad: Can the vanishing lake be saved?, BBC News Africa, 31 Mar 2008.

[4]    Hansen, K., The Rise and Fall of Africa's Great Lake, Earth Observatory, NASA, 9 November 2017.

[5] Coe, M. and Foley, J., Human and natural impacts on the water resources of the Lake Chad basin. Journal of Geophysical Research, Atmospheres, 2001, 106 (D4) 3349-3356.

[6] Ibid.

[7]  Okonkwo, C. et al, Combined Effect of El Nino Southern Oscillation and Atlantic multidecadal oscillation on Lake Chad level variability, Cogent Geoscience, Hydrosphere, 2015.

[8] Gao, H et al.,  On the causes of the shrinking of  Lake Chad, Environmental Research Letters, 2011, 6(3).

[9] Ross, W., op. cit.

[10] Beverly, E., , In 100,000 years Lake Victoria has dried up three times - It could happen again, Quartz Africa, January 2020.

[11] Ibid.

[12] Ivory, S.J. et al, Climate vegetation and weathering across space and time in Lake Tanganyika (tropical eastern Africa), Quaternary Science Advances, vol. 3, April 2021.

*Board of the Society of African Earth Scientists: Dr Enas Ahmed (Egypt), Osmin Callis (Secretary - Guyana/Nigeria), Mathada Humphrey (South Africa), Ndivhuwo Cecilia Mukosi (South Africa), Damola Nadi (Nigeria),  Dr Chukwunyere Kamalu (Chair - Nigeria).