The role of nature-based solutions in climate change adaptation: a systematic analysis of urban plans from South American cities

Urban areas in the Global South are highly vulnerable to climate-related hazards, yet systematic evidence on how adaptation is planned and operationalised remains limited. This study provides a structured assessment of urban climate adaptation by analysing 64 local adaptation plans from 37 South American cities with populations exceeding one million. We develop and apply a comparative analytical framework to measure the types of adaptation measures proposed, the role, purpose, and integration of nature-based solutions (NbS), and emerging patterns in urban adaptation planning.

Our analysis shows a strong emphasis on educational, informational, and behavioural measures, while engineering and technological interventions are comparatively underrepresented. Adaptation strategies differ systematically by hazard type: NbS are most frequently proposed for flood and heat risk reduction, whereas drought adaptation relies more heavily on engineering and technological approaches. We further show that national adaptation plans exert a measurable influence on local planning priorities, either enabling or constraining the uptake of NbS. Across cities, the findings reveal key gaps in adaptation planning, particularly in public health and risk-transfer measures, which are rarely considered.

By moving beyond qualitative accounts, this study offers a comparative and measurable evaluation of urban adaptation planning in South America. The findings provide actionable insights for policymakers, urban planners, and donors, and establish a basis for tracking progress, identifying blind spots, and strengthening the use of NbS in urban climate adaptation.