Lake Turkana, the world's largest desert lake, is likely to receive more rain and frequently overflow its banks, placing 15 million shore residents in jeopardy.
The wetter future is predicted by the UN Environment Programme (UNEP) in a new report.
The report said over 20 years, climate change will likely cause heavier rains over the lake's river inflows. This extra water will raise water levels in the lake and increase the likelihood of severe flooding.
"Many people think climate change is a problem for the future,” Frank Turyatunga, deputy head of UNEP’s Africa office, said.
“But as Lake Turkana shows, it's happening now and it's already forcing people to adapt to new conditions.”
While severe, abrupt flooding has been rare, climate change projections foresee flooding becoming more regular and impacting more people if adaptation measures are not put in place.
The report called for improved international cooperation and reforestation, agro-forestry and avoiding construction in areas at risk of flooding.
“In the last two years, rising water levels in Lake Turkana have damaged pastureland, inundated buildings and forced people to flee their homes,” Tito Ochieng, director of water in Turkana county.
Lake Turkana is part of the Omo-Turkana basin, which stretches into four countries: Ethiopia, Kenya, South Sudan and Uganda.
The basin is home to many rare plants and animals.
The study urged officials in Kenya and Ethiopia, which both border Lake Turkana, to prepare for a future in which once-rare floods, such as those in 2019 and 2020, are regular occurrences.
For years, the lake has appeared to be drying up.
Its main river inflows have been blocked to some degree by dams and many feared water levels would drop by two-thirds, causing the lake to cleave into two smaller bodies of water.
It was, one report said, "an African Aral Sea disaster in the making” – in which only 10 per cent remains of the original sea.
The study also found evidence of rising water levels in the eight lakes lining Kenya’s Rift Valley.
Severe flooding in those lakes in 2019 and 2020 damaged homes and infrastructure — and led to a spike in attacks by crocodiles and hippos venturing into flooded shores closer to human habitation.
Since 1988, Ethiopia has built a series of hydroelectric dams on its main tributary, the Omo River, leading to predictions of Lake Turkana’s demise.
A mindset persists in Kenya that lake water levels are constantly falling, which makes planning difficult, UNEP said, despite rising lake levels.
Using sophisticated water resources modelling and climate change scenario analysis, the UNEP report found that as many as eight human settlements around the lake could be inundated periodically by flooding.
Africa stands out disproportionately as the world's most vulnerable region to climate change.
This vulnerability is driven by the prevailing low levels of socioeconomic growth in the continent. While climate change is global, the poor are disproportionately vulnerable to its effects.
UNEP’s climate change work in Africa supports countries to implement their climate action commitments — Nationally Determined Contributions (NDCs) — to meet food security, create income and opportunities for youth and economic expansion.
The report was part of a wider project designed to accelerate cooperation in the border areas among Ethiopia, Kenya and Somalia.
The project also developed an open-source information portal on the basin, based in part on satellite imagery. It contains data on land cover, water quality and soil moisture and examines the various climate change scenarios.
The report follows the launch of the UN Decade on Ecosystem Restoration 2021-2030, a global push to revive natural spaces. It is also part of UNEP’s wider work to monitor and restore freshwater ecosystems worldwide, supporting a Sustainable Development Goal.
(Edited by V. Graham)