Mixed approaches - Nature-based solutions and integrated urban resilience

Urban Resilience and Climate Adaptation: Evidence on Green Spaces, Urban Agriculture and Food Security in African Cities
Urban Resilience and Climate Adaptation: Evidence on Green Spaces, Urban Agriculture and Food Security in African Cities

African cities face growing climate risks while also confronting food insecurity, environmental degradation and unequal access to urban resources. This evidence examines how urban green spaces and urban agriculture can contribute to climate resilience, food security and more inclusive urban development.

The analysis draws on primary survey data collected from 547 respondents, including households, urban producers and municipal representatives, across selected cities in Senegal. The evidence combines socioeconomic analysis, spatial and environmental indicators, and quantitative modelling to examine food security, knowledge and perceptions of urban green spaces, and factors associated with participation in urban agriculture.

The findings show that climate resilience is closely connected to access to local food systems, environmental resources and household socioeconomic conditions. Urban agriculture contributes to household food security, while income, remittances and other socioeconomic characteristics influence food-security outcomes. The analysis also identifies gender differences in perceptions and satisfaction related to urban green spaces, highlighting unequal experiences of urban environmental resources. Evidence from urban producers further shows that access to finance and production constraints shape participation and the capacity to sustain urban agricultural activities.

The results suggest that climate adaptation policies in African cities should move beyond infrastructure-focused responses and better integrate green spaces, urban agriculture, food systems and inclusive local economic opportunities. Policies should also consider gender and socioeconomic differences and strengthen support for producers through finance, technical assistance and local planning.

Evidence on the Effectiveness and Cost-Effectiveness of Ecosystem-Based Disaster Risk Reduction in LMICs
Authors: Suchi Kapoor Malhotra, Ashrita Saran, Ratika Bhandari, Kevin Ouma Ojiambo, Sujata Shirodkar, Gavin Stewart, Howard White, and Hugh Sharma Waddington. Affiliations: Campbell South Asia, Global Development Network, Makerere University, Newcastle University, London School of Hygiene & Tropical Medicine, and London International Development Centre

Climate change is increasing exposure to natural hazards, particularly in low- and middle-income countries (LMICs). Ecosystem-based disaster risk reduction (Eco-DRR) can reduce risks while protecting and restoring natural systems, but evidence on its effectiveness and economic value remains fragmented. This rapid systematic review synthesised evidence on the effectiveness and cost-effectiveness of Eco-DRR interventions in LMICs.

This rapid systematic review synthesised 58 studies: 28 effectiveness evaluations, 20 economic evaluations and 10 modelling studies. Evidence Effectiveness evidence, mainly on green infrastructure and protected areas, indicated benefits for hazard incidence and exposure and natural capital outcomes, including reductions in forest fires and increases in forest and vegetation cover. Evidence on human development outcomes was limited. Economic evaluations generally found that Eco-DRR interventions generated benefits exceeding costs, with favourable benefit-cost ratios reported for flood-risk reduction, early warning systems, land-use planning, capacity building and mangrove restoration.

Significant evidence gaps remain, including limited evidence across hazards, interventions, equity and distributional outcomes, and incomplete assessment of indirect and non-monetised benefits. The findings indicate that Eco-DRR can contribute to climate adaptation and disaster-risk management, while highlighting the need for stronger evidence to inform equitable and effective climate action.

Nature for climate in cities: Where are nature-based responses prioritised in policy — and where are they missing?
Authors: Nora Nisi and Nina Schoonman, researchers at the International Institute for Environment and Development.

‘Working with nature’ is increasingly championed as an effective ‘win–win’ climate response, with nature-based solutions (NbS) promoted as affordable and adaptable responses to climate change. Yet it remains unclear how far this agenda has translated into policy in the global South, particularly in cities and informal settlements where climate risks are acute. This study examines how nature is mobilised in climate change, disaster risk reduction and urban development policy across Bangladesh, Cambodia, Ecuador, Honduras, Kenya and Sierra Leone. It uses “nature-based responses” (NbR) as an umbrella category encompassing NbS, ecosystem-based adaptation, green infrastructure and specific nature-based actions such as tree planting, allowing analysis beyond NbS terminology alone. A quantitative keyword-frequency analysis, supported by qualitative content analysis, was used to review 42 national and sub-national policy documents. The analysis first assessed the overall prevalence of NbR across the policy sample, then examined the extent to which NbR were specifically referenced in urban and informal-settlement contexts. We found that NbR appeared in 90% of documents, but explicit NbS in only 29%. Urban NbR appeared in 57% and urban NbS in 19%, while only 5% explicitly linked NbR/NbS to informal settlements. The findings call for well-designed NbS that explicitly pursue climate, biodiversity and human-wellbeing co-benefits; treating urban nature as essential resilience infrastructure; recognising informal settlements as legitimate sites for NbS investment; and mainstreaming NbS into policy, planning and budgets. We also emphasise NbS as part of broader urban resilience planning and the use of justice- and equity-centred design to address existing urban inequalities and minimise risks such as displacement and green gentrification.

Do climate-resilient backyard gardens strengthen household income and resilience? Evidence from Belize
This impact evaluation assesses a backyard-garden intervention in Belize that provided vulnerable households with tailored agricultural inputs, small livestock, tools and technical training. A phase-in randomized controlled trial was used to estimate effects on household income, dietary outcomes and resilience to shocks. The intervention significantly increased total household income and crop income and produced positive effects on several measures of households’ ability to withstand climate-related shocks. Beneficiary households reported less severe effects of shocks on income, food production and assets and relied less on some external coping mechanisms. However, overall dietary diversity did not improve significantly. The report also cautions that the 6–16 months observation period may be too short to assess the sustainability of effects. The findings show that a targeted household adaptation intervention can improve income and short-term shock management without automatically improving all dimensions of household well-being.