The researchers worked in cooperation with the University of Manchester’s African Cities Research Consortium, selecting twelve cities chosen to reflect the continent’s diversity in geography, climate, economy, culture, and urbanisation history. The set includes heavily studied metropolises such as Accra, Nairobi, Dar es Salaam, and Lagos, alongside severely under-researched cities like Bukavu, Freetown, Maiduguri, and Mogadishu. After screening more than 3,100 search results with machine-assisted tools and manual review, the team coded each documented intervention by actor, spatial scale, implementation status, response type, and potential synergies or trade-offs, then contextualised the results against a composite index combining climate exposure, social vulnerability, and infrastructure deficit.

The imbalance between adaptation and mitigation is not accidental, the authors argue, but rooted in the architecture of international climate finance. Mitigation programmes globally receive roughly 30 billion US dollars compared with 16 billion for adaptation and a mere 2.7 billion for integrated strategies. More than half of adaptation programmes, 57 percent, are loan-financed, and disbursement ratios hover around 46 percent. The cost-benefit logic of climate finance privileges measurable emission reductions over the diffuse, context-specific benefits of adaptation, creating what the study calls a paradox: African cities contribute least to global warming, with average per capita emissions of around 2.5 tonnes per year compared with 27 tonnes in cities like Rotterdam, yet the financing system disadvantages precisely those cities for whom adaptation is the urgent imperative.

To quantify where co-beneficial measures might be falling behind, the researchers introduced what they call the Synergy Gap, calculated as the difference between the general implementation rate and the rate at which actions with cross-domain benefits are implemented. Positive values signal that singular interventions are outpacing synergistic ones, a pattern the authors attribute to siloed governance structures that treat adaptation and mitigation as separate policy domains. About 32 percent of all recorded actions carried potential synergies, and the largest share, 51 percent, fell into a category the study labels the NBS-Sequestration Nexus: nature-based solutions such as tree planting, mangrove restoration, and green infrastructure that cool neighbourhoods and buffer floods while also sequestering carbon.

The geography of implementation is strikingly uneven. Nairobi, Dar es Salaam, and Lagos consistently show the highest levels of reported climate activity and implementation, while Addis Ababa, Freetown, and Mogadishu sit at the lower end. In Addis Ababa, roughly 90 percent of recorded actions consist of plans and recommendations rather than concrete implementations, despite strong problem awareness among city planners regarding drinking water, sewage, and flooding. Accra, together with Lilongwe, shows the largest Synergy Gap in the dataset, with promising policy frameworks on solid waste, energy, and transport undermined by weak cross-sectoral execution. In contrast, Nairobi, Freetown, and Maiduguri are the only three cities where more synergistic actions are implemented than singular ones, driven mainly by local and multi-actor initiatives.

One of the study’s most consequential findings concerns who actually gets things done. Households and communities achieve higher implementation rates than government-led measures across the twelve cities, and multi-actor collaborations also perform comparatively well. Autonomous actions were overwhelmingly coded at the household and community levels, with half of household actions being behavioural or cultural practices such as savings strategies and improved waste handling. Yet these are the least resourced actors in the climate finance landscape. The authors note that this partly reflects a research bias, since studies tend to document community practices only once they are already observable, while government planning is researched regardless of whether it is ever implemented. Still, the pattern underscores a structural tension: the potentially most effective actors are the least funded.

Informal settlements emerge as both the epicentre of climate vulnerability and a blind spot in the evidence base. Actions targeting informal settlements account for 37 percent of the sample, with the highest shares in Nairobi at 77 percent and Lilongwe at 67 percent, but only 3 percent in Addis Ababa despite its slum population share of around 72 percent. The study devotes considerable attention to the conceptual difficulties of informality, noting that the term is a malleable socio-political construct and that formal and informal sectors are so interpenetrated in many African cities that separating them is, as one cited scholar puts it, ridiculous. Data on informality, the largest dimension of most African cities, are rarely publicly available, and urban indicators often aggregate formal and informal dimensions in ways that obscure intra-urban inequality.

Data scarcity itself emerges as a methodological finding. For Bukavu, Freetown, Maiduguri, and Mogadishu, fewer than ten publications per city exist, and the authors caution that the apparent positions of Bukavu and Maiduguri in their comparative analyses very likely reflect data artefacts rather than actual activity levels. Mogadishu, despite facing among the most urgent climate pressures, remains one of the least researched capital cities in Africa, with minimal solar and wind adoption despite favourable conditions. The authors stress that reported action levels are as much a function of research attention as of actual implementation, an epistemic bias they link to the framing of Southern Urbanism, which rejects applying Euro-American urban theory to cities shaped by colonial and postcolonial dynamics.

Trade-off risks, though less frequent than synergies, cluster in worrying ways. Of 268 potential trade-offs recorded, representing 14 percent of all actions, half relate to social exclusion, followed by potential ecosystem harm at 26 percent. The authors warn that when technical and utilitarian values dominate nature-based interventions, the social and cultural dimensions of human-nature relations central to how African communities experience climate risk are marginalised. Excess rainfall is the most frequently recorded climate stressor across half the cities, associated with nearly 60 percent of preventative adaptation goals, while temperature extremes concentrate in Accra, Addis Ababa, and Dar es Salaam.

The study’s conclusions are deliberately framed as hypotheses rather than definitive rankings, given the exploratory nature of comparing cities with such uneven evidence bases. But its prescriptions are clear: integrated, multi-scalar approaches anchored in better data and dynamic frameworks are essential to align urban climate action with Africa’s heterogeneous urban realities. The authors call for flexible, co-produced typologies that can distinguish settlements appearing similar from above but diverging on the ground, dedicated funding windows for community-government coalitions, and governance reforms that overcome the compartmentalisation of adaptation and mitigation. As the scientific community prepares the IPCC’s forthcoming Special Report on Cities, the message from these twelve African cities is that integration is not simply another box to check, but a precondition for climate action that works.

Subject of Research: Integrated climate change adaptation and mitigation interventions, synergies, and co-benefits in African cities

Article Title: Lessons from integrated climate change adaptation and mitigation interventions for synergies and co-benefits in African cities

Article References: Bodenstein, C.-P., & Lwasa, S. (2026). Lessons from integrated climate change adaptation and mitigation interventions for synergies and co-benefits in African cities. Discover Cities, 3(1), Article 174. https://doi.org/10.1007/s44327-026-00359-0

Image Credits: AI Generated

DOI: 10.1007/s44327-026-00359-0

Keywords: climate adaptation, climate mitigation, African cities, synergy gap, co-benefits, nature-based solutions, informal settlements, urban climate finance, Southern Urbanism, climate governance, urban vulnerability, infrastructure deficit

The study arrives at the intersection of two defining challenges of the twenty-first century: climate change and population ageing. Their convergence is particularly acute in China, which faces both a rapidly ageing population and an escalating frequency of devastating floods that cause annual economic losses exceeding ten billion US dollars. For older adults, floods carry risks well beyond immediate physical danger, including heightened rates of injuries, post-traumatic stress disorder, depression, and the exacerbation of diabetes and cardiovascular and respiratory conditions. These outcomes directly undermine healthy ageing, defined by the United Nations Decade of Healthy Ageing as the process of developing and maintaining the functional ability that enables well-being in older age.

To capture how nature-based solutions might counteract these harms, a research team led by Binhua Fu and Joseph Kimuli Balikuddembe of Sichuan University’s Institute for Disaster Management and Reconstruction conducted a scoping review following the Arksey and O’Malley framework and the PRISMA-ScR reporting guidelines. The team searched PubMed, Scopus, and Google Scholar for qualitative studies published between 2000 and early 2025, focusing on research that examined nature-based solutions for flood risk reduction—such as Sponge City infrastructure, green infrastructure, wetland restoration, and ecosystem-based adaptation—in settings across mainland China. Of 622 retrieved records, only 13 studies met the eligibility criteria, a finding that itself underscores how nascent and fragmented this evidence base remains.

The analytical machinery behind the review is worth noting for its technical sophistication. The researchers extracted data into six healthy ageing outcome domains aligned with the World Health Organization’s conceptual framework: physical activity and mobility, mental health, cognitive functioning, well-being and social support, environmental quality, and economic security. They then employed narrative synthesis alongside a Sankey diagram analysis, generated in R using the networkD3 package, to visualize weighted flows connecting geographical context, flood type, intervention type, and health co-benefit. This multi-level edge-list approach, in which each conceptual connection was weighted by its frequency across eligible studies, provided a quantitative representation of the dominant pathways within the qualitative literature.

Geographically, the evidence base spans at least nine provinces and provincial-level municipalities, with case studies concentrated in major urban centers such as Wuhan, Shanghai, and Guangzhou, and in designated pilot Sponge Cities including Guiyang and Ningbo. Temporally, the field is moving fast: ten of the thirteen included studies were published from 2020 onwards, coinciding with the scaling of China’s Sponge City Program amid mounting climate risks. Urban or pluvial flooding dominated the literature, addressed in ten of the thirteen studies, with fluvial, riverine, and general flooding covered by single investigations. Permeable pavements, rain gardens, bioswales, green roofs, and wetland restoration were consistently perceived as effective at reducing surface runoff and easing pressure on drainage networks.

The synthesis’s central revelation is the breadth of co-benefits these interventions deliver. The most prominently documented domain was psychosocial well-being and social support: aesthetically pleasing, accessible green spaces became hubs for conversation, leisure, and recreation, directly strengthening social and peer support networks and mitigating loneliness among older residents. Mental health benefits followed closely, with one study in Guangzhou linking the use of urban green infrastructure to measurable decreases in anxiety, dysphoria, and emotional exhaustion, and other studies reporting stress relief, relaxation, and high perceived aesthetic and health value. Physical activity and mobility improved as Sponge City features provided convenient, walkable spaces after rain, while urban parks encouraged walking and cycling.

Environmental improvements formed a cross-cutting co-benefit with direct implications for independent living. Studies reported enhanced air quality, noise mitigation, and cooling effects that reduce urban heat islands, creating safer and more comfortable outdoor environments for older adults. Cognitive functioning evidence was thinner but tantalizing: a single study associated urban green infrastructure use with memory enhancement, suggesting a possible pathway for NbS to support cognitive health in later life. Economic and community participation benefits emerged from multifunctional designs that integrated productive landscapes, including community engagement in risk-adaptive agriculture within flood detention zones and the use of green infrastructure spaces for vegetable and flower gardens—activities representing livelihood diversification, economic savings, and meaningful occupation for retired residents.

The review’s authors are equally candid about what the evidence lacks. Their analysis identified five principal gaps: an exclusively urban focus that neglects rural elderly populations; a methodological reliance on perceived rather than objectively or clinically measured benefits; a conceptual gap in which older adults appear only as incidental subsets of broader studies rather than central subjects of gerontological research; a thematic gap with cognitive function and nutrition severely underexplored; and an economic gap in the absence of quantified financial impacts on older persons. Sample sizes for older adult subgroups varied enormously, from as few as three retired persons to 95 participants aged 56 and above, and several key studies failed to report age-disaggregated data at all.

The policy implications are nonetheless substantial. The authors argue that the co-benefits provide a tangible pathway to operationalize China’s parallel national commitments to its “ecological civilization” vision and the Healthy China 2030 strategy, framing Sponge City rain gardens and urban wetlands not as drainage projects but as practical manifestations of a dual mandate: managing floodwater while creating the green, accessible environments that promote physical activity, mental restoration, and social connection. The economic case is compelling, the authors contend, because fostering environments that support activity, well-being, and cohesion can function as primary prevention, potentially reducing the incidence and severity of age-related chronic conditions and easing the mounting financial burden on China’s social and healthcare system—a perspective consistent with the One Health paradigm that treats investments in ecosystem health as direct investments in human health.

The rural blind spot carries particular equity weight. Rural communities in China are often on the front lines of riverine and pluvial flooding, yet they remain conspicuously absent from research on nature-based co-benefits, a disparity the authors warn risks exacerbating health inequalities among the elderly. They point to low-cost, replicable approaches such as flood-adaptive farming, grassland management, and riparian ecosystem restoration as candidates for scaling in rural settings, where older residents may be even more dependent on their immediate environment for both income and social connection.

The study’s limitations also shape its recommendations. The review was restricted to English-language publications, potentially excluding relevant Chinese-language studies, and, as is standard for scoping reviews, no formal critical appraisal of individual study quality was conducted. The predominance of qualitative and mixed-methods designs, while essential for understanding lived experiences and contextual factors, means the magnitude of health impacts remains unmeasured. The authors urge researchers to adopt longitudinal and mixed-methods designs employing validated health metrics, and call on policymakers and urban planners to intentionally design and evaluate nature-based solutions with geriatric outcomes as a primary objective, ensuring equitable distribution between urban and rural settings.

For a country that simultaneously confronts an “aging tsunami” and intensifying floods, the message of this review is that flood control and healthy ageing are not separate policy problems but two faces of the same infrastructure investment. If future research can move beyond perceived benefits to establish causal pathways and quantify costs, nature-based flood risk reduction may prove to be one of the most cost-effective preventive health strategies available to ageing societies in China and far beyond its borders.

Subject of Research: Beyond Flood Control: A Scoping Review Deciphering the Co-benefits of Nature-Based Flood Risk Reduction for Healthy Ageing in China

Article Title: Beyond Flood Control: A Scoping Review Deciphering the Co-benefits of Nature-Based Flood Risk Reduction for Healthy Ageing in China

Article References: Fu, B., Balikuddembe, J. K., Lu, Y., Yang, A., Di, B., Tian, B., & Reinhardt, J. D. (2026). Beyond Flood Control: A Scoping Review Deciphering the Co-benefits of Nature-Based Flood Risk Reduction for Healthy Ageing in China. International Journal of Disaster Risk Science. https://doi.org/10.1007/s13753-026-00741-x

Image Credits: AI Generated

DOI: 10.1007/s13753-026-00741-x

Keywords: Beyond, Flood, Control, Scoping, Review, Deciphering, Co-benefits, Nature-Based, Risk, Reduction, Healthy, Ageing