Scientists have found that the deadly floods across parts of West Africa in recent weeks were made more likely and intense by human-driven climate change, while the expansion of cities into flood-prone areas amplified the devastation, raising the thorny problem of how to better protect poorer urban communities.
A report from the World Weather Attribution (WWA) group highlighted how the floods hit some of West Africa’s most densely populated coastal regions, where rapid urbanisation has pushed formal and informal settlements dangerously into floodplains, while converting land into farms has reduced drainage.
Since May, West African countries including Ghana, Togo, Côte d’Ivoire and Nigeria have experienced weeks of torrential rain and deadly flash floods. Homes have been submerged, thousands of people displaced and over 70 people killed.
WWA scientists said climate models showed that human-induced climate change increased the intensity of the rainfall, with what was once a rare amount of rain falling in just three days – a downpour that can now be expected every two to four years.
“The event is not rare already today and therefore the flood risk is certainly not going away but will increase in particular with additional pressures from growing populations and urbanisation,” said Friederike Otto, a professor of climate science at Imperial College London.
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Scientists have found that the deadly floods across parts of West Africa in recent weeks were made more likely and intense by human-driven climate change, while the expansion of cities into flood-prone areas amplified the devastation, raising the thorny problem of how to better protect poorer urban communities.
A report from the World Weather Attribution (WWA) group highlighted how the floods hit some of West Africa’s most densely populated coastal regions, where rapid urbanisation has pushed formal and informal settlements dangerously into floodplains, while converting land into farms has reduced drainage.
Since May, West African countries including Ghana, Togo, Côte d’Ivoire and Nigeria have experienced weeks of torrential rain and deadly flash floods. Homes have been submerged, thousands of people displaced and over 70 people killed.
WWA scientists said climate models showed that human-induced climate change increased the intensity of the rainfall, with what was once a rare amount of rain falling in just three days – a downpour that can now be expected every two to four years.
“The event is not rare already today and therefore the flood risk is certainly not going away but will increase in particular with additional pressures from growing populations and urbanisation,” said Friederike Otto, a professor of climate science at Imperial College London.
Impact made worse by informal settlements
On top of climate change, scientists said urbanisation, inadequate drainage, poor waste management and the expansion of informal settlements into floodplains have left millions more people exposed to flooding.
Informal settlements are neighbourhoods which develop without authorisation from government authorities. More commonly known as slums or shanty towns, they often lack land tenure and services like running water and electricity and tend to be home to poorer communities.
Across West Africa and much of the developing world, as people have moved from rural areas to cities in search of work, these settlements have expanded into wetlands, flood-retention areas and riverbanks. This has further heightened flood risks across West African cities.
Kiswendsida Guigma, technical advisor at the Red Cross Red Crescent Climate Centre, said West Africa’s coastal cities are being “squeezed between repeated flooding and rapid urban growth”, pushing infrastructure beyond its limits and making it harder for communities to recover.
Roussel Teguia, a post-doctoral research fellow at Canada’s Université Laval, said the recent floods have exposed longstanding failures in urban planning across West Africa’s fast-growing coastal cities where much of the region’s economy is concentrated.
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Teguia said the floods are deadlier due to factors including rapid urbanisation in low-lying areas, lack of affordable housing alternatives and the long-standing marginalisation of poor communities. He also condemned the destruction of wetlands, mangroves and floodplains for roads and buildings when instead these natural bodies “should be treated as critical public safety infrastructure”.
“These floods should not be understood only as natural disasters,” he said. Residents of informal settlements must stop being treated as the problem, since they are often the first victims of “an urban model that exposes them to risk and then blames them for being exposed”, he added.
Short-sighted approach to relocation
Cote d’Ivoire’s capital Abidjan recorded 59 of the deaths, with about 20 dying in the densely-settled slope neighbourhood of Mossikro. Local media reported that authorities had previously relocated residents from this area due to fears about vulnerability to deadly landslides and flooding, but some people had returned to previously evacuated sites and died when the hillside collapsed due to the rain.
Local authorities have since started demolishing houses in the area, to the anger of many locals who say they were not consulted or warned about the demolitions, which are costing them their properties and livelihoods. “If you destroy this place, where am I supposed to go?” one unnamed resident told Al Jazeera.
The government says many of the structures were built illegally in flood and landslide-risk zones and it plans to move 3,000 people first and 2,000 more later. Municipal official Yue Hilaire told the TV channel the municipality has been trying to persuade them to leave for a long time. “Frankly we are tired,” he said. “The mayor instructed us to evict them because we don’t want to witness another tragedy every year.”
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Guigma said that to avoid people returning, the government should ensure that “where people are relocated they also have relatively good economic opportunities for them to stay”.
Demolishing poor people’s homes without offering real alternatives is not prevention, Teguia argued, calling on governments to provide safe, serviced and affordable land close to jobs and transport, stop the occupation of wetlands and regulate powerful land owners and users.
Relocation programmes often fail because they are designed as land-clearing or security operations rather than social processes, he explained.
Governments must move from reactive crisis management measures to a long-term comprehensive approach to risk, Teguia said. Relocation policies need to be just, fairly compensated, include affected communities and encompass economic and social networks – otherwise they “simply move the vulnerability elsewhere”, he warned.
Finance gap limits flood response
The WWA scientists said deadly floods will continue unless governments do more to reduce people’s exposure and vulnerability, calling for investments in safe and affordable housing, improved drainage and sanitation, stronger enforcement of building regulations, more effective early warning systems and greater involvement of at-risk communities in planning.
Joyce Kimutai, research associate in extreme weather and climate change at Imperial College London, said the study is a clear example of “the need for international cooperation on climate justice”, adding that developed countries have a responsibility to help nations like Togo, Cote d’Ivoire and Ghana to adapt to a worsening problem that, as low emitters of greenhouse gas, they did not cause.
But significant financial support for countries grappling with increasing climate disasters may still be some way off. Earlier this month, the UN’s fledgling Fund for Responding to Loss and Damage (FRLD) postponed approving its first round of projects after requests for support far exceeded the money available.
One of the roughly 180 submissions the fund received was a Nigerian recovery and resilience project to address flood losses and damage in Lagos which is prone to yearly flooding.
Otto of Imperial College London said such situations where the role of climate change is certain “should be the kinds of events where this fund should pay and help, but of course, that would require first money to be in the fund”.
Ghana and Togo have also identified increasingly frequent flooding as a major climate risk in their national adaptation plans, prioritising investments in drainage, resilient infrastructure, flood management, early warning systems and climate-resilient urban planning.
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But while these adaptation plans acknowledge that delivering the proposed measures requires more international aid, wealthy nations are likely to have missed their 2025 goal of doubling adaptation finance for developing countries. Funding reached just over $30 billion in 2024, far below the target of $40 billion by 2025.
The WWA findings underscore the urgent need to speed up support for vulnerable communities who have done little to cause climate change, said UN Climate Change Executive Secretary Simon Stiell, adding that “all climate finance commitments must be delivered in full”.
