Nature-based Solutions (NbS) have been gaining attention in the context of urban “upgrading projects” in informal settlements in the Global South (Cohen-Shacham et al., 2016). Ranging from raingardens to green roofs, tree planting or mangrove restoration initiatives, these projects have multiple functions including producing food, providing cultural value and serving as public space. In the context of informal settlements, areas historically characterized by reduced access to infrastructure and services (UN Habitat III, 2017), NbS have been framed as important strategies capable of mitigating some of the impacts of climate change such as heat waves and flooding (Sengupta, 2016; French et al., 2020; Sattherthwaite et al., 2020; Rauf et al., 2021).

The recent literature on experiences with NbS in the Global South indicates that community gardens and tree planting efforts are common, but community participation is still incipient in most informal settlement “greening” initiatives (Puskás et al., 2021; Kiss et al., 2022). While this trend is similar to that in wealthier urban centers, where NbS projects are still too rarely co-designed with local residents (Frantzeskaki, 2019; Kiss et al., 2022), there are challenges and controversies specific to the informal settlement context. Reflecting on those, several authors have warned against NbS-centered upgrading initiatives for reproducing unequal power relations and exacerbating existing vulnerabilities (Cousins, 2021; Kotsila et al., 2021; Seddon, 2022). While the literature indicates an interest to involve the communities in the implementation of NbS, examples of successful and just community involvement in the design of NbS in the Global South are still rare (Gouverneur, 2014; Das and King, 2019; French et al., 2020). This Perspective paper presents such examples and insights into how participation and project vision (the goals, values and expected outcomes that guide each initiative) are intertwined in NbS projects in informal settlements.

Transformative development of NbS in informal settlements entails discussions about institutional, social and ecological systems (Diep et al., 2019; French et al., 2020). The term “transformative” here refers to the reorientation of society's capacity toward proactive, transdisciplinary, multi-stakeholder initiatives that foster the development of novel solutions (De Graaf-van Dinther and Ovink, 2021). Transformative development should be guided by the fair distribution of benefits and risks (Mcmillan et al., 2021) as well as the prioritization of local livelihoods, including systems linked to food production and income generation. This is only possible by supporting institutional changes and acknowledging social and ecological processes within the settlements “through broad participation, including traditional, local, and scientific knowledge, as well as the distribution of benefits in a fair and equitable manner” (Cousins, 2021, 6).

The participatory ladder is a model for analyzing participation within informal settlement upgrading projects. Based on Sattherthwaite et al. (2020)'s reflections on housing and infrastructure-provision initiatives, the ladder identifies approaches that range from non-participatory, tokenistic and exploitative projects to highly collaborative, community-led efforts. While this framework provides a useful tool to evaluate the institutional aspects of upgrading projects, it assumes that higher levels of participation necessarily lead to more successful projects as it does not directly reflect on how participatory approaches affect goals, values and expectations throughout the project. In the context of NbS implementation, we consider that Sattherthwaite et al.'s ladder is insufficient to analyse an aspect essential to transformative initiatives: the social and ecological relationships that underpin NbS in informal settlements.

Expanding Sattherthwaite et al.'s ladder, we argue that the transformative potential of an NbS is not only determined by the participatory approach used but, more importantly, by how this approach can transform the project vision and ensure that the NbS can be integrated with the local needs and environments. This is important because common types of NbS in informal settlements (including wetlands, green areas, and community gardens) are inevitably intertwined with social and ecological dimensions by providing services such as food production and income generation as well as playing cultural and spiritual roles in their contexts (Hamel and Tan, 2021). As such, transformative initiatives should be informed by socio-ecological systems and guided by the willingness to revise project's goals, values and expectations during the design and implementation of NbS.

There is a spectrum of community involvement in the implementation of NbS in informal settlement upgrading projects, ranging from non-participatory to transformative approaches (Figure 1, left-hand side). In parallel, there is a spectrum of ways in which NbS projects consider local needs and environments, represented by the categories of “project visions” ranging from initiatives that only replicate foreign initiatives to projects that are highly integrated with local social and ecological relationships (Figure 1, right-hand side). Combining these two elements suggest that projects with low levels of community participation generally lead to the replication of solutions developed in other locations. This is particularly challenging since informal settlements and their relationships with their surrounding contexts can vary significantly and, for this reason, require different approaches (Mulligan et al., 2020). On the other side of the spectrum, projects that strive for a transformational practice and deep community participation will lead to NbS being well integrated to the socio-ecological contexts. In the following, we illustrate the different levels participation and implications for project vision with examples from the literature and the authors' own experience.

In this Perspective article, we discussed examples of engagement practices that illustrate how consultative, co-designed and transformative approaches can be achieved. Drawing on lessons from the authors' own practices, we systematized our findings in the form of a framework, which adapts previous conceptual model of upgrading to the context of NbS (Sattherthwaite et al., 2020). This framework posits that transformative approaches should involve multiple stakeholders in order to foster positive changes in the institutional and socio-ecological systems. These approaches can be translated into connected and integrated visions of NbS if they are able to consider local priorities and environmental contexts.

Connecting with the needs of communities in their own terms should be a central aspect of transformative approaches toward NbS. Recent research on the topic indicates that this can be supported by the involvement of “gatekeepers” who promote that all voices are recognized and heard, and that local knowledge is integrated into project plans (Diep et al., 2022). The work of NGOs and grassroots movements can offer insights into how researchers and practitioners spearheading the use of NbS can overcome barriers that reinforce “power dynamics that restrict the participation of historically excluded actors” (p. 280; Woroniecki et al., 2020; Melanidis and Hagerman, 2022).

The examples highlight the importance of involving local actors who can champion deeply personal engagement practices to advance transformative approaches to NbS. The work of the NGO Rame Rame Jakarta in Indonesia, for example, is premised upon engagement practices that are not dictated by experts and technical requirements. Instead, by using emotional mapping, transect walks and other engagement practices with informal workers, their work offers opportunities for communities to play a key role in the process of mapping their environments and co-producing knowledge. These processes are key to accelerating institutional change and materializing new forms of multi-stakeholder governance of NbS (Frantzeskaki and Kabisch, 2016; Cousins, 2021).

The multi-stakeholder engagement practices in these projects were made possible through an iterative process that expanded beyond informative and consultive approaches and allowed NbS to be integrated with local needs and priorities that local stakeholders can relate to. Based on these examples, we argue that a transformative approach to NbS requires a different model of participation, one that is tightly connected to local ways of understanding the environment and its social relationships. Due to the multidimensional socio-ecological nature of NbS, it is important to highlight that manipulative and informative approaches are insufficient to support a just and site-specific implementation of these systems. Instead, a transformative practice should be premised on the understanding that community participation should inform the goals, values and expected outcomes of projects implementing NbS in informal settlements.

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

EW oversaw the research, co-designed the framework, and edited the manuscript. HR wrote the initial draft, co-designed the framework, edited the manuscript, and designed the supplementary material. PH co-designed the framework, reviewed, and edited the manuscript. LD reviewed and edited the manuscript. BN and KK provided papers and information for the research. All authors contributed to the article and approved the submitted version.

This research is supported by National Research Foundation, Prime Minister's Office, Singapore (award NRF-NRFF12-2020-0009).

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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