“Exceptionally heavy” rainfall that led to deadly flooding across southern Africa in recent weeks was made more intense by a combination of climate change and La Niña.
This is according to a rapid attribution study by the World Weather Attribution service.
From late December 2025 to early January, south-eastern Africa was hit hard by intense downpours that resulted in more than a year’s worth of rain falling in some areas in just a few days, according to the study.
This led to severe flooding that left at least 200 people dead, thousands sheltering in temporary accommodation and tens of thousands of hectares of farmland waterlogged.
The analysis finds that periods of intense rainfall over southern Africa have become 40% more severe since pre-industrial times, according to observations.
The authors say they were unable to calculate how much of this increase was driven specifically by climate change, due to limitations in how climate models simulate African rainfall.
However, the study notes that the researchers “have confidence that climate change has increased both the likelihood and the intensity” of the rainfall.
The authors also note that the El Niño-Southern Oscillation phenomenon played a role in the “devastating” flooding, estimating that a La Niña event made the rainfall around five times more likely.
Major disruption
The heavy rainfall started on 26 December last year and intensified from early January. The most-extreme rainfall took place between 10 and 19 January.
The countries most affected by the floods, and analysed by the study, are Eswatini, Mozambique, South Africa and Zimbabwe, with some areas receiving up to 200mm of rain, according to the study authors.
Study author Bernardino Nhantumbo – a researcher at Mozambique’s National Institute of Meteorology – told a press briefing that in just two or three days, some areas recorded the amount of rainfall that is “expected for the whole rainy season”.
The map below shows the areas most affected by intense rainfall over 10-19 January. Darker blue indicates a greater accumulation of rainfall, while light green indicates less rainfall. The pink box shows the study area.
In Mozambique, the floods damaged nearly 5,000km of roads, which has hindered the transport of goods and affected pharmaceutical supply chains, the study says. In Zimbabwe, bridges, roads and infrastructure were “significantly damaged or destroyed”.
More than 75,000 people have been affected by the floods in Mozambique, according to the study. BBC News reported the floods were the worst seen “in a generation” in the country.
Dr Izidine Pinto, a climate scientist from Mozambique currently working at the Royal Netherlands Meteorological Institute, told a press briefing that the country was particularly affected because it “lies downstream of major river basins”.
The flooding prompted Mozambique’s education minister to consider rescheduling the start of the academic year, according to Channel Africa.
In South Africa, the country’s weather service said that areas receiving more than 50mm of rain over 11-13 January were “widespread”, with some places seeing up to 200mm.
South Africa’s Kruger National Park – the largest national park in South Africa – was severely damaged by floods and temporarily closed after several rivers burst their banks, reported TimesLIVE.
The South African news outlet quoted environment minister Willie Aucamp as saying: “The indication is that it will take as long as five years to repair all the bridges and roads and other infrastructure.”
Extreme rainfall
The peak of the rainy season in southern Africa falls between December and February.
To put the extreme rainfall into its historical context and determine how unlikely it was, the authors analysed a timeseries of 10-day maximum rainfall data for the December-February season.
They find that in today’s climate, extreme rainfall events of the scale seen this year in southern Africa would be expected only once every 50 years.
They add that such events have become “significantly more intense”, with observational data showing a 40% increase in rainfall severity since pre-industrial times.
The map below shows accumulated rainfall over Eswatini, Mozambique, South Africa and Zimbabwe over 10-19 January, as a percentage of the average December-February rainfall for the region over 1991-2020.
Green shading indicates that the rainfall in 2026 was higher than in 1991-2020, while brown indicates that it was lower. The red box indicates the study region.
The study explains that in January and February, rainfall patterns in southern Africa are “strongly influenced” by the El Niño-Southern Oscillation (ENSO), a naturally occurring climate phenomenon that affects global temperatures and regional weather patterns.
La Niña is the “cool” phase of ENSO, which typically brings wetter weather to southern Africa.
Pinto told the press briefing that “most past extreme rainfall events [in the region] have occurred during La Niña years”.
The authors estimate that the current weak La Niña event made the extreme rainfall five times more likely and increased the intensity of the event by around 22%.
For attribution studies, which identify the “fingerprint” of human-caused climate change on extreme weather events, scientists typically use climate models to simulate and compare worlds with and without global warming.
However, many models have limitations in their simulations of African rainfall. In this study, the authors found that the models available to them cannot “adequately capture” the influence of ENSO on rainfall in the region.
Study author Prof Fredi Otto, a professor in climate science at the Imperial College London, told a press briefing that these limitations are “well known”. They stem, in part, because the models were “developed outside of Africa” by modellers with different priorities, she explained.
This means that the authors were unable to calculate how much more intense or likely the rainfall event was specifically as a result of human-caused warming.
However, Otto explained that the authors are “very, very confident that climate change did increase the likelihood and intensity of the rainfall” to some extent. This is because the observations all show an increase in rainfall over time and other existing literature supports this assumption, she added.
She told the press briefing that the results of this study were “definitely not 100% satisfactory”, adding that this study will “definitely not be the last of its kind in this region”.
(These findings are yet to be published in a peer-reviewed journal. However, the methods used in the analysis have been published in previous attribution studies.)
Vulnerability
The study warns that the flooding “exposed deep and persistent social vulnerability in the region”.
The authors say that a large proportion of the population – especially in urban areas – live in poor housing with “inadequate planning and insufficient provision of basic services”.
Paola Emerson, head of office at the UN Office for the Coordination of Humanitarian Affairs (OCHA) in Mozambique, told a UN press briefing about the flooding that nearly 90% of people in the country live in traditional adobe houses that “basically melt after a few days’ rains”.
In a WWA press release, study author Nhantumbo explained:
“When 90% of homes are made of sun-dried earth, they simply cannot withstand this much rain. The structural collapse of entire villages is a stark reminder that our communities and infrastructure are now being tested by weather they are just not designed to endure.”
Study author Renate Meyer – an adviser with the conflict and climate team at the Red Cross Red Crescent Centre – said in a WWA press briefing that the “recurring frequency of hazards such as drought and extreme rainfall have had a significant impact on communities experiencing, amongst others, displacement, health challenges, socioeconomic loss and psychological distress”.
For example, the World Health Organization (WHO) said in a press release that the event had disrupted access to health services and increased the risks of water- and mosquito-borne diseases, as well as respiratory infections across southern Africa.
Meyer explained that the countries included in this study have “substantial populations living below or near the poverty line with limited savings, low insurance cover and a high dependence on climate sensitive livelihoods”.
The post Climate change and La Niña made ‘devastating’ southern African floods more intense appeared first on Carbon Brief.
Climate change and La Niña made ‘devastating’ southern African floods more intense
One of the key expected outcomes from the upcoming COP31 climate summit in Antalya, Turkey, is the launch of a “just transition mechanism”.
This follows years of calls from civil society to support a “just transition” as countries shift towards low-emissions energy systems and away from fossil fuels.
At the COP30 UN climate talks last year in the Brazilian city of Belém parties agreed to establish a “mechanism” to support this goal, called the “Belém-Antalya mechanism” (BAM).
Groups that have championed the BAM want it to act as a central hub on just transitions, providing support for workers and communities around the world.
However, the details of exactly what the much-touted BAM will consist of remain vague, with developed and developing countries disagreeing about its functions and purpose.
Disagreements continued at the UN climate talks in Bonn in June 2026, including on the crucial question of how the BAM will be financed.
Here, Carbon Brief looks at where the idea for the BAM came from, how it could support just transitions and what to expect from COP31.
How has a ‘just transition’ featured in UN climate talks?
A “just transition” is the idea that workers and communities should be supported in the shift to a low-carbon economy. It is a central principle behind the idea of climate justice.
Often, the term refers to those linked to the fossil-fuel industry, but it can also refer to transitions taking place in agriculture, heavy industry and various other sectors.
The concept originated in the 1980s, when US labour unions forged alliances with environmental justice groups. It has since become a key part of international climate discussions.
The preamble to the 2015 Paris Agreement includes a commitment to “tak[e] into account the imperatives of a just transition of the workforce and the creation of decent work and quality jobs in accordance with nationally defined development priorities”.
Bert De Wel, policy officer at the International Trade Union Confederation (ITUC), tells Carbon Brief:
“The labour movement is very happy with the wide audience and broad political support that the concept has received since its inception in the 1980s. The inclusion in the Paris Agreement, with the reference to the creation of decent work and quality jobs was a milestone for the movement. While other demands have been added…we continue to stress the labour dimension as being central to the concept.”
Three years after the creation of the Paris Agreement, at COP24 in the former coal-mining city of Katowice, the Polish presidency highlighted the issue of just transitions.
The need for carbon-cutting policies to ensure “a just transition of the workforce” that creates “decent work and quality jobs” was included in the “Silesia declaration”, issued by the presidency during the first week of COP24.
While the declaration was only signed by 50 countries – roughly a quarter of the parties at the summit – it was still “noted” in the final COP text.
This helped to drive momentum behind the idea, culminating in formal agreement at COP27 in Egypt to launch a “work programme on just transition” (JTWP).
De Wel says the establishment of the JTWP was a “major step forward” that allowed parties to “speak about just transition in more concrete terms”.
In the years since, negotiators have worked to flesh out the JTWP, with disagreements between parties about what its purpose should be.
Broadly, developed countries would like it to focus on domestic workforces, while some nations want a more global outlook, including support for transitions in developing countries.
The JTWP has proved a challenging negotiating space, with talks at the COP29 summit in 2024 closing without an agreement, in what one observer dubbed a “betrayal”.
However, despite these frustrations, parties at COP30 in Brazil agreed to establish a new institutional mechanism on just transitions, which has become widely known as the BAM. The move was hailed as a “victory” by civil society.
Where did the ‘just transition mechanism’ come from?
In the run-up to COP30, civil society began to push for the establishment of an “institutional arrangement” that would move work under the JTWP from talk into action.
(This was originally called the “Belém action mechanism” by civil society groups, who subsequently updated this to the “Belém-Antalya mechanism” following the outcome at COP30. However, in the JTWP text agreed at COP30 it is only described as a “mechanism”, sometimes also referred to as the “just transition mechanism”.)
Anabella Rosemberg, senior advisor on just transition at NGO umbrella group Climate Action Network (CAN) International, tells Carbon Brief:
“The idea of the mechanism emerged from the collaboration of civil society, trade unions, feminist groups, youth and Indigenous peoples in the UNFCCC.
“It was clear that the kind of activities being run under the JTWP – two dialogues a year and one ministerial – would not support the delivery of just-transition strategies on the ground, so a new approach was developed to get words into action.”
Following the inception of the idea, civil society did “tonnes of stuff to boost it up the agenda”, Dr Leon Sealey-Huggins, a senior campaigner at the charity War on Want, tells Carbon Brief.
This ranged from presenting demands and proposals to different constituents, organising joint letters and writing policy papers, all the way through to designing logos, creating memes and even a song.
These efforts ultimately paid off: during the Bonn climate negotiations in June 2025, one draft text included the idea for a new institutional arrangement. One of the options in the draft text was for a “toolbox, guidance framework, global platform, technical assistance network [or] mechanism”.
![Paragraph 28 of the JTWP text published 25 June 2025. The text reads "28. Options for further implementation of the United Arab Emirates just transition work programme Option 1: Improving existing modalities Option 2: New institutional arrangements [toolbox, guidance framework, global platform, technical assistance network, mechanism] Option 3: Defer decision to 2026"](https://www.carbonbrief.org/wp-content/uploads/2026/11/para28-1024x334.png)
This inclusion was broadly welcomed as a “big win” for civil society groups, although parties acknowledged that more needed to be done to flesh out the idea.
Going into COP30, civil society groups continued to push the idea of creating a BAM, with protests, banners and badges visible around the venue.
Early in negotiations, the G77 and China – a large coalition of developing countries at UN climate talks – put forward their own proposal for a just transition “mechanism”. This, they suggested, could provide technical assistance, support international cooperation and help to foster partnerships in an effort to address implementation gaps.
Their proposal faced initial pushback from developed-country parties including Norway, the UK and others, who opposed it due to concerns that it would duplicate existing systems and require additional funding.
Developed countries also opposed the use of the term “mechanism”, with the EU suggesting an “action plan” as a potential alternative. Nevertheless, the creation of a “mechanism” was included in the final draft text on the JTWP.
This text was formally approved during the COP30 closing plenary to extended applause from many in the hall.
In a statement at the time, Chiara Martinelli, director at CAN Europe, welcomed the decision:
“Delivering BAM was a major civil society win. It creates a coordinated institutional home to drive forward progress on the just transition.”
The decision to develop the mechanism included a request for parties to work over the subsequent year – through to COP31 – on a plan to get things started.
What role could the mechanism play in facilitating ‘just transitions’?
According to civil society, the BAM could help tackle the fractured just-transition landscape by centralising resources and helping to overcome a number of barriers.
Speaking to Carbon Brief, Rosemberg says the just-transition space “lacks coordination and the right kind of support and is quite disconnected from climate action imperatives”. She adds:
“The BAM can play a role in bringing those [people] trying to make just transition happen together, identify gaps and barriers, foster cooperation and accelerate support.”
Civil society has put forward a number of proposals likely to inform the structure of the BAM. Most consist of a mechanism with three parts, which would encompass and expand upon the work that is currently being carried out under the JTWP.
One proposal by a coalition of five NGOs suggests the mechanism is formed of a steering body, a “knowledge arm” and an “implementation arm”.
The steering body would coordinate the work of the two arms of the BAM, including deciding the topics that should be discussed under the ongoing JTWP, which will continue to feature in climate negotiations. They suggest the body would recommend topics that require negotiation when “gaps that require political guidance are identified”.
Their proposal is illustrated in the infographic below, showing the steering body acting as a central hub for work within the BAM.
The final part of the BAM, the “implementation arm”, would act as a hub to enable and coordinate technical, financial and knowledge-based assistance for those pursuing a just transition.
Rosemberg says the vision of civil society is for work to go “beyond negotiators’ dialogues”. She says the BAM could enable the organisation of a “matchmaking platform” to provide support faster, as well as dedicated groups to identify and mobilise financial resources. She adds:
“Finally, through bottom-up identification of barriers, the BAM can also allow a discussion on enabling just transition that is informed by practitioners. The BAM can show that implementation does not necessarily mean taking issues outside of the UNFCCC.”
A separate proposal for the structure of the BAM from the Global Campaign to Demand Climate Justice (DCJ) – a separate coalition of NGOs – similarly proposes three elements. These would be: coordination and coherence; knowledge generation; and international cooperation and support.
Sealey-Huggins, who is affiliated with DCJ, notes:
“If it works in practice, what we’ll see is a cascade of just-transition policies implemented across countries, across sectors in a unifying, transformational moment for justice-centered climate action, and that will be the key to unlocking the transition that’s been missing so far.”
Another proposal for the BAM comes from the Grantham Institute at the London School of Economics. It suggests the three functions of the mechanism should be capacity-building, technical assistance and knowledge-sharing, but it recommends a dual-arm structure comprising a policy arm and an operational arm.
De Wel tells Carbon Brief that while there is “rather broad consensus on the functions”, parties are pushing in “very different directions” on how the BAM will be set up.
What are the financial implications of the mechanism?
Within UN climate negotiations, some parties have raised concerns about the potential cost of the mechanism.
The push to launch the BAM comes at a time when the UNFCCC itself is facing a funding gap, following the US withdrawal. Several other parties have also delayed or reduced their contributions, in response to changes in domestic priorities.
This has led to the UNFCCC cancelling events and not filling vacated positions, as the organisation struggles to