A NextGen Blog by Lauren Rose, University of Exeter.
All Photos © Alison M. Jones, unless otherwise noted.
This is the latest post to our NWNL NEXTGEN BLOG series. Since 2007, NWNL has supported watershed education with college internships and blogging opportunities. This NWNL NEXTGEN BLOG series posts students’ essays; sponsors a forum for our student contributors; and invites upper-level students to propose work focused on watershed values, threats and solutions.
Lauren graduated from the University of Exeter and the University of Queensland with a degree in Zoology. She is currently pursuing a master’s degree in Island Conservation and Biodiversity with Jersey International Centre of Advanced Studies. She believes nature-based solutions best help our expanding human population live in harmony with the natural world. This post investigates the impact of climate change in two NWNL watersheds – the Mara and Omo River Basins – which together span Ethiopia, Kenya and Tanzania – and affect the White Nile watershed, as the Mara River flows into its source, Lake Victoria..
Climate change is one of the greatest threats facing humans and the natural world. Rapidly-growing human populations worldwide have sought faster development and have exploited resources, subsequently increasing greenhouse gases. This has resulted in a 2° F (1° C) increase in global mean surface temperature since the pre-industrial period.[mfn]Hoegh-Guldberg[/mfn] Although this slight degree change may not appear to be a major concern, the repercussions are both significant and concerning. This amplified rate of changing climates, increased by human activity, has left the world struggling to adapt in such a short timeframe.
Freshwater is a limited resource, becoming increasingly scarce as its demand surges with growing human populations.[mfn]Vörösmarty, Charles[/mfn] Climate change is having profound impacts on watershed-scale hydrological processes and is disproportionately impacting developing countries.[mfn]Xu, Chong-yu[/mfn],[mfn]Paavola Jouni and Adger, Neil[/mfn]East Africa is predicted to receive an increase in average annual rainfall and more frequent extreme weather events such as fires, floods, hurricanes and droughts.[mfn]Orindi, Victor[/mfn],[mfn]Cambridge University Press[/mfn],[mfn]Wara, Michael et al.[/mfn] In 2019, East Africa’s ‘short-rains’ season (October-December) was one of the wettest in history, causing floods, landslides and impacting over 2.8 million people.[mfn]Collier, Paul et al.[/mfn] This region is at an even higher risk, due its vulnerable economy and lack ofresources needed to adapt.[mfn]Wainwright, Caroline et al[/mfn] Additionally, increased average temperatures are predicted to exacerbate malaria conditions, further threatening socio-economic development in East Africa.[mfn]Endo, Dr Noriko et al.[/mfn]
The Mara River Basin
East Africa’s Mara River Basin stretches between Kenya and Tanzania, measuring approximately 13,750 km2. The Mara River is born in the Mau Escarpment of Kenya’s Rift Valley; travels through the Maasai Mara National Reserve and the Serengeti National Park; and then drains into Lake Victoria. Current threats to the Mara River Basin include deforestation, expanding agriculture and population growth.[mfn]Ombara, Doris[/mfn]
Climate change is seen through the changing seasonal distribution of rainfall, rising temperatures, and extreme weather events. The average temperature is expected to increase by 33° to 36° F (0.7º to 1.97º C) by 2030 – and by 35° to 37° F (1.5º to 2.71° C) in 2050. The duration of heat waves in both Kenya and Tanzania is also predicted to increase, further impacting human health, agriculture and the environment. The consequent heat stress and reduced water availability will create a domino effect by increasing poverty, perpetuating food insecurity and decimating wildlife populations from heat stress and reduced water availability.
The Mara River Basin is incredibly biodiverse. It harbors 473 freshwater species, over 90 mammal species, 214 resident bird species, 4 reptile species, 20 amphibian species, 40 fish species, 50 invertebrate species and 141 vascular plant species.[mfn]World Wildlife Fund[/mfn] In addition, there are hundreds more species that are yet-to-be-discovered in this area and many migratory and seasonal species that rely on this water source. In particular, it is home to one of the seven ‘Wonders of the World’ – the Great Migration. Every year over 2 million wildebeest migrate from Tanzania to Kenya, crossing the Mara River in search for greener pastures. The Mara River holds the only remaining permanent water source for this irreplaceable overland migration.[mfn]National Geographic[/mfn] Since these animals follow the seasonal local rains, any major shifts in water availability and distribution greatly affect their livelihoods.
Regarding populations, that are now increasing by 3-4% annually in East Africa, this same dependance on freshwater availability impacts the growing demand for agricultural and livestock food sources. The resulting pressure for more crop fields and grazing lands has led to further deforestation, which in turn is altering microclimates, eroding soil and reducing water quality.[mfn]Zermoglio, Fernanda, et al.[/mfn] By 2030, water demand in the Mara River Basin is predicted to increase by 49-180%, due to climate change droughts, deforestation of the Mau Forest Complex and increasing commercial irrigation withdrawals. These pressures will undoubtably result in water conflicts due to competitive demands and limited water.[mfn]Omonge, Paul, et al.[/mfn] There is also the possibility that proposed upstream dams will withhold critical water flows needed downstream by iconic and globally-treasured fauna in Kenya’s Maasai Mara and Tanzania’s Serengeti ecosystems. This will threaten tourism, conservation and thus development within this globally significant watershed.
The Omo River Basin and Lake Turkana Basin
Significantly larger than the Mara River Basin, the transboundary Omo River Basin (131,000 sq km/ 50,579 sq mi ) flows from southern Ethiopia’s Shewan highlands south across the border into Kenya’s Lake Turkana.[mfn]Kraljevic, Andrea, et al.[/mfn],[mfn]Omo-Turkana Research Network[/mfn] Lake Turkana is the world’s largest desert lake and depends heavily on the Omo River, which supplies 90% of its water.[mfn]Omo-Turkana Research Network[/mfn] Koobi Fora, on the northeast shore of the lake is a World Heritage site, famous for the Leakey family’s discovery of some of the earliest evidence of humankind. Today, Lake Turkana supports several indigenous tribes that total 300,000 people. Many Turkana, Rendille, Dassenech, El Molo and other tribal fishermen rely on this lake for survival.[mfn]Arnold, David[/mfn] Lake Turkana research has shown that the shoreline of its shallow Ferguson’s Gulf (on the lake’s northwestern shore) has significantly receded and its mouth has narrowed by 1km [0.6 mi].[mfn]Hodbod, Jennifer, et al.[/mfn] Such a reduction in the capacity of water in Ferguson’s Gulf could severely endanger its critical fish nursery that has previously thrived in this Gulf.
Upstream in Ethiopia, other indigenous tribes – including the Karo, Nyangatoum and Mursi – have depended on the annual flooding of the Omo River for over 6,000 years to deposit fertile soil and water to nourish their crops planted along the river’s banks.[mfn]Kraljevic, Andrea, et al.[/mfn],[mfn]Omo-Turkana Research Network[/mfn] A huge supply of water from annual monsoons in the highlands has supported these tribes’ tradition of flood-recession agriculture, allowing them to be self-sufficient in this arid basin, despite severe climate-change droughts in southwest Ethiopia. However, Ethiopia’s recent construction of its Gilgel Gibe III Hydroelectric Dam – the third of five to be built- has exacerbated the effects of climate change on this watershed’s wildlife and people.[mfn]Kraljevic, Andrea, et al.[/mfn] The Gibe III withholds the flow of monsoonal waters to the Omo in order to supply irrigation for huge new Asian-owned plantations for thirsty crops such as cotton and sugar. This situation, exacerbating impacts of climate change, means Omo tribes can no longer depend on flood-recession agriculture for subsistence. Furthermore, it also means water levels in Lake Turkana could drop by up to 10 meters (33 ft), which will unquestionably have a cascade of effects on local people and wildlife.[mfn]Arnold, David[/mfn]
As both the Mara and Omo River Basins face severe impacts of climate change, increased regulation of water usage and distribution for commercial agriculture is essential to ensure adequate provisioning in the future.[mfn]Hodbod, Jennifer, et al.[/mfn] Water is the most indispensable natural resource in these watersheds; yet it has been more often than not taken for granted. Impacts of climate change can often be difficult to recognize or quantify, however, thanks to recent research, this issue is beginning to be addressed at many levels – from grassroots tribal councils to the central governments. On a local, national and transboundary scale, all African countries would greatly benefit from sustainable and managed water usage. However, efforts must be also made at a global scale, as well as at all levels of management, to work towards combating climate change for all populations – especially those who have not been major contributors to greenhouse gas emissions. Only through global understanding, united policymaking and immediate action to reduce carbon emissions can multitude layers of disaster be averted. After all, prevention can be better than a cure!
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Collier, Paul et al. “Climate change and Africa.” Oxford Review of Economic Policy, pages337–353, 2008.
Endo, Dr Noriko et al. “Impact of climate change on malaria in Africa: a combined modellingand observational study.” The Lancet, page S7, 2017.
Hodbod, Jennifer, et al. “Social-ecological change in the Omo-Turkana basin: A synthesis of current developments.” Ambio, pages 1099-1115, 2019
Hoegh-Guldberg, Ove et al. “The human imperative of stabilizing global climate change at1.5°C.” Science, DOI:10.1126/science.aaw6974, 2019.
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Wara, Michael et al. “El Niño-like conditions during the Pliocene warm period,” Science, page758-761,2005.
World Wildlife Fund. Mara river biodiversity report. 2005. https://www.wwfkenya.org/mara_river_biodiversity_report
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Zermoglio, Fernanda, et al. “Vulnerability and adaptation in the mara river basin.” USAID From the American people, May 2019, Accessed Feb 15 2021, by LR. https://reliefweb.int/sites/reliefweb.int/files/resources/2019_USAID_ATLAS_Vulnerability%20Assessment%20of%20the%20Mara%20River%20Basin.pdf