A new global study finds cities are not taking advantage of the full potential of nature-based solutions

“A new global study finds cities are not taking advantage of the full potential of nature-based solutions”

  • Research conducted by a group of researchers at the Basque Centre for Climate Change (BC3) and the University of Almería, Sean Goodwin (BC3 and the University of Almería), Marta Olazabal (BC3 and Ikerbasque), Antonio J. Castro (University of Almería), and Unai Pascual (BC3 and Ikerbasque), published in Nature Sustainability, identifies critical pathways for making progress on the application of nature-based solutions to climate change adaptation in cities. The study uses data from 216 projects implemented in 130 cities worldwide.  

Bilbao, a 2 de febrero de 2023

Nature-based solutions (NbS) have been identified as a critical strategy for achieving the ambitious global goals of mitigating and adapting to climate change and halting and reversing biodiversity loss, all while addressing the social challenges that each of these issues create and exacerbate. Supporters of NbS highlight their strength in addressing each of these areas because of their cascading benefits across human well-being and ecosystem health. This is made explicit by a recent joint publication by the Intergovernmental Panel on Climate Change (IPCC) and the Intergovernmental Panel on Biodiversity and Ecosystem Services (IPBES) in what they call the “climate-biodiversity-society” (or, CBS) nexus.

New research from a team of researchers between the Basque Centre for Climate Change (BC3), Ikerbasque, and the University of Almería, led by La Caixa INPhINIT fellow and doctoral researcher Sean Goodwin and now published in Nature Sustainability (find a free read-only copy here), explains how current NbS applied globally are addressing the CBS nexus, and whether (and how) they are promoting real long-term change when they are used to help cities adapt to climate change (currently a blind-spot in scientific understanding). Several key take-away messages emerge that are significant both for science and policy-makers.

Pictured: Map of the distribution of projects analysed within the study ranging from lower (light blue) to higher (dark blue) distribution (Fig.1 in article, credit Springer Nature Limited)

The first is that projects using NbS need to pay more attention to how they address context-specific CBS challenges. 

For example, only 2% of NbS studied took into account how future climate change impacts would affect the NbS themselves, as Marta Olazabal explains: “As solutions based on natural processes, the specific plant species used within the context of NbS are also as vulnerable to climate change as people. If they are to provide benefits into the future, NbS themselves need to be designed to be resilient to changing climate conditions. For example, species need to be resilient to high temperatures or drier conditions in certain locations.

Vulnerability to climate change can and should be reduced in multiple and complementary  ways through NbS. In this study, however, the authors found that current NbS are mainly designed to reduce exposure and do not work from other angles of climate vulnerability.  For example, NbS more often attempt to reduce exposure to climate hazards by diverting heavy rainfall so that flooding is avoided (e.g. floodable parks). Moving forward, NbS need to address the needs of urban dwellers on how to enact their own adaptation strategies in their communities and homes (e.g., capturing water to use it when there is scarcity) and reduce the severity of the impact of hazards overall (e.g., by helping cool down houses and apartment blocks).

The findings of this study point out that people need to be more at the centre of NbS design. In that regard, the researchers found that consideration of social issues is uneven among NbS projects analysed. While almost all NbS considered some form of social justice in how they were designed and implemented, this mostly related to superficial procedures of stakeholder consultation. Only 28% of projects evidenced deeper engagement with how to consider diverse (and marginalised) values in NbS implementation, and only 20% made explicit consideration of ensuring benefits (and burdens) arising from NbS were distributed in a just manner. In terms of project governance, around 80% of all projects were funded and implemented by public actors, mostly municipal governments, further highlighting a vulnerability in the longevity of NbS as they are subject to the shifting priorities and budgeting of city governments.

Pictured: Aeriel view of São Paulo, where the city doubled the coverage of green space available to its citizens over continued efforts over decades through its “100 parks program” (photo courtesy of Lucas Marcomini on Unsplash).

Finally, another thing that the authors studied was the capacity of NbS of creating real long-term change (also called “transformative change”) in these cities. They studied the impact of NbS projects on the ecological system, on society and on the infrastructure of the city. They found that less than 15% of the projects evidence transformative capacity on either of these dimensions. The authors attribute these trends to “…the lack of social engagement beyond superficial public consultation (social change), the piecemeal approach to improving conditions for urban biodiversity (ecological change) or due to the project’s limited connection to city-wide urban planning rules and norms (technical change)”. These trends differed regionally, as NbS in Latin American and African cities were leading the way in terms of ecological and social transformation.


The second recommendation then relates to the kinds of information that can be used to do a systematic study of this magnitude. The information that formed the basis for this analysis came from various online databases containing project information on NbS from all over the world. Sean Goodwin highlights: “In our work, it was important to include information from a variety of viewpoints globally, not just the Global North, and we saw these databases as our best chance to capture a higher diversity of regional information than had previously been done.” However, it has still been the case that 63% of the projects from these databases were from Europe alone, and in the future, more support needs to be given to make the on-the-ground efforts of people implementing NbS in a diversity of regions visible. These include efforts from projects like the Equator Initiative and PANORAMA, two databases used as sources for information in the study that aim to do just that. This is critical in efforts to synthesise learnings from NbS globally to further improve and grow the approach, as was the goal of the researchers, as otherwise critical contextual information, is missed that accounts for a diversity of local conditions and experiences.

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María de Maeztu Excellence Unit 2023-2027 Ref. CEX2021-001201-M, funded by MCIN/AEI /10.13039/501100011033

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