A systematic review of nature-based solutions for climate action in African cities

Abstract

Nature-based solutions (NbS), including ecosystem-based adaptation (EbA), are increasingly proposed for climate action in African cities, but the evidence base is fragmented and lacks systematic synthesis of what is being implemented, where, and how effectively. We analysed 112 studies retained from a systematic review, covering 134 urban areas across 42 countries and including 45 informal settlements. Five NbS typology classes are inductively derived including: Green spaces; Rivers, catchments and drainage systems; Coastal systems; Green buildings; and Urban agriculture and multi-use gardens. Urban green spaces dominate the evidence (49% of studies) and are the most multi-functional class. Urban agriculture and multi-use gardens are under-recognised in headline framings, named as primary in only 5% of studies but appearing in 34% of the wider intervention mix. Evidence is increasing but concentrates geographically on larger cities. Successful climate change adaptation and mitigation outcomes are reported by 72% and 27% of studies, respectively. Heat mitigation is the most frequently quantified adaptation outcome, with temperature reductions up to 12.2°C reported in proximity to urban green and blue spaces across the continent. Qualitative evidence links urban NbS to effective coastal protection, flood risk reduction, and increased water security. Multi-stakeholder governance anchored by local actors, and meaningful community participation are consistent enablers of effective implementation. However, insufficient long-term funding and livelihood disruptions and displacement raise concerns about long-term impacts. Priority research gaps include longitudinal effectiveness monitoring, financing mechanisms for informal contexts, systematic assessment of mechanisms behind inequitable outcomes, and evidence from under-represented regions and smaller cities.