According to a 2021 OECD report, two-thirds of African cities are at “extreme” risk of climate and water-related shocks. Violent climate events, heat waves and droughts are thus at the top of the risks incurred by urban areas. Rapid urbanization, unsustainable development and degradation of natural ecosystems exacerbate these risks. 

Nature-based solutions (NBS), which rely on natural ecosystems and the services they provide to human activities, address these urban challenges, while simultaneously providing benefits in terms of human well-being and biodiversity. However, they are still little integrated into urban planning processes and decision support tools available to planners. The lack of knowledge, data and experimentation on nature-based solutions therefore hampers their adoption and deployment. 

The objective of this research project is to enable, through the construction of a strategic framework, the deployment and scaling of nature-based solutions, in particular to address water and heat risks. The challenge is to improve the ecological resilience of cities by helping them identify the risks they must prepare for, to assess the potential of NBS to address them and to develop implementation and funding strategies for these NBS as part of the urban planning process. 

A fast, effective and practical methodology for assessing the potential of nature-based solutions will be made available to the cities of Addis Ababa and Kigali, which are the two pilot cities of this research project. The project is led by WRI, in partnership with the Addis Ababa Urban Development Department, the Ethiopian Institute of Architecture and the Rwanda Young Water Professionals Association. This methodology is intended to be adopted by other urban centers to allow a broader appropriation and mobilization of NBS in cities. 

At the methodological level, the construction of a strategic framework for nature-based solutions is interesting for two reasons:

• Identification of flood risks, heat islands, water supply and biodiversity potential of cities through the production of composite maps and the mobilization of satellite data;
• Participatory construction of the strategic framework through workshops with stakeholders of both cities to validate the priority areas of intervention and identify the NBS most adapted to the issues of each area.  

Developed by the WRI research team with the cities of Addis Ababa and Kigali, the Strategic NbS Framework can support cities in selecting and implementing appropriate nature-based solutions (NbS). 

By integrating globally available data sets with local data, it helps identify areas of a given city that are susceptible to extreme flooding and heat, as well as opportunities to expand urban green spaces and create ecological corridors. 

To ensure successful implementation, collaboration between public authorities, technical experts, and community leaders is essential. Using this framework, citywide maps can be quickly generated to identify priority areas. After a validation by city stakeholders, field experts then play a key role in designing effective NbS, tailored to local conditions. 

Although it has limitations in data detail, the Framework provides a solid starting point to build sustainable cities. Additional guidelines provide technical information on usable NbS, as well as case studies. These guidelines are available for download below: 

Download the guidelines

A webinar from the Research Conversations series was held to present the project's findings, and these research findings are summarized in a policy brief available for download below.

The research project identified a series of lessons to facilitate the deployment of nature-based solutions (NbS), taking into account the specific needs of cities. These lessons highlight the potential of nature in urban resilience planning and climate action:

• To increase awareness and institutional integration:

1. Set up multi-stakeholder processes to support dialogue and the prioritization of identified NbS.
2. Rely on case studies to facilitate understanding and engagement.

• To enhance data availability for more effective planning:

1. Combine local and global datasets to carry out multi-hazard assessments (flooding, urban heat islands, etc.).
2. Encourage citizen science initiatives for data collection, and ensure it is considered in decision-making.

• To strengthen planning and implementation linkages:

1. Establish dedicated governance structures (such as a mayoral committee) to coordinate various technical services involved and mobilize funding.
2. Develop common reference frameworks (design standards, guidelines, etc.) to strengthen political and public support.

• To secure long-term financing:

1. Integrate NbS into existing city investment programs.
2. Include strategies for public-private partnerships and use a multi-benefit assessment framework to demonstrate their long-term value.

• To adapt solutions to the local context and ensure monitoring:

1. Launch NbS pilot projects with monitoring systems to track their performance.
2. Integrate gender, equity, and inclusion considerations from the selection phase of each NbS.

Latin America is the second most urbanized region in the world, with 81% of its population concentrated there. This strong urbanization, its rapid growth and the weakness of urban planning policies affect areas of high ecological and environmental value. However, natural ecosystems can be a source of solutions for those involved in urban design and development, in particular to respond to the risks generated or exacerbated by climate change.

Understanding nature-based solutions (NBS), studying their implementation conditions and analyzing their integration into public policies is therefore necessary to ensure the livability of cities in the long term. While NBS and green infrastructure are still recent in the urban landscape, initiatives have been deployed for several years and are a privileged source of data to exploit. 

The ENSLAC (Enabling Nature based solutions Scale-up in Latin American Cities) project aims to analyse the mechanisms that enable the scale-up of nature-based solutions implementation in Latin American cities, drawing on 15 case studies in Peru, Colombia and Ecuador. This research approach aims to: 

• Analyze the challenges of ecological restoration for the management of risks related to the impacts of climate change in urban areas;
• Understand the levers for using NBS as a tool for urban planning and development;
• Identify the temporal, technical, cultural, political, social, financial and cooperative processes that have enabled large-scale NBS-based projects;
• Assess the influence of national or supranational strategies and policies on NBS development;
• Disseminate the knowledge produced by focusing on formats and channels that can be used for the training of urban development actors. 

To explore these issues, Yes Innovation, based in Quito, works with the Humboldt Institute for Biological Resources Research, an institution linked to the Ministry of the Environment of Colombia, and Periferia Territorios Vivos, a Peruvian organization specialized in urban planning with an ecological approach. 

This research project uses two analytical tools (depending on the case study and the available field data):

1. Temporal and spatial analysis (known as BA/CI, which refers to a Before/After and Conservation/Intervention analysis);
2. Comparative analysis between case studies on NBS and reference cases of comparable characteristics but without implementation of NBS. 

The ENSLAC research project aims to: 

• Understand mechanisms that enable scale-up of nature-based solutions as a tool for urban and peri-urban planning;
• Identify replicability levers of these NBS for Latin American cities;
• Produce training materials for urban development actors. 

The research team presented its findings during a webinar from the Research Conversations series. The replay is available below (in French and Spanish).