Perrine Hamel’s research while affiliated with Nanyang Technological University and other places

Southeast Asia's urban population faces climate risks in the form of flooding, drought and urban heat. Residents of informal settlements often experience the most severe risk due to higher exposure and increased vulnerability to climate hazards. As climate adaptation projects flourish, there is a need to better characterize the hazards, e.g., magnitude of floods and ambient temperatures, and monitor project effectiveness, e.g., reduction in flood or temperatures due to an intervention. This is particularly true for nature-based solutions such as river restoration or tree planting, for which the evidence base is more limited in the region. In this chapter, we synthesize the climate risks in informal settlements in Southeast Asia and opportunities for nature-based solutions to mitigate such risks. Next, we describe three technological approaches-low-cost sensors, IT tools for citizen science, and satellite imagery-that show strong potential to improve climate risk assessment and management in informal settlements. Finally, we present two case studies applying these technologies to better assess climate hazards in informal settlements. The first exemplifies the potential of low-cost temperature sensors to assess heat exposure in informal settlements, while the second illustrates the use of citizen science in community flood monitoring. We conclude with a discussion on the upscaling of these technologies in informal settlements and the role of institutes of higher learning in promoting climate resilience in the region.

Nature-based solutions (NbS) have gained traction in Southeast Asia and the Pacific region over the last decade. While the benefits of NbS are established for most urban contexts, more research is necessary to examine the potential of these solutions in the Global South, particularly in historically disadvantaged contexts such as informal settlements. Responding to this gap, we analyse both grey and academic sources to examine past NbS projects in informal settlements in Southeast Asian and Pacific countries. We identified six main types of NbS that are used to address various social, ecological, and cultural challenges in informal settlements. Some NbS are different from those described in the Global North, ranging from the use of traditional community gardens to enhance food security to the implementation of constructed wetlands as wastewater treatment systems. NbS in the region are often framed as grassroots initiatives spearheaded by local communities or as technical systems implemented within “upgrading programs” delivered by multilateral banks, researchers or international organisations. Analysing the motivations behind these projects, we provide insights into which systems have been used in response to specific needs such as efforts to promote climate adaptation, support food security or compensate residents for disruptions. We outline important social and political implications of the implementation of NbS still understudied in the literature, such as the framing of NbS as “placeholders” for future development or as “compensation” for the disruptions caused by resettlement projects.

Land-use land-cover (LULC) changes are occurring rapidly in Southeast Asia (SEA), generally associated with population growth, economic development and competing demands for land. Land cover change is one of the vital factors affecting carbon dynamics and emissions. SEA is an important region to study urban-caused LULC emissions and the potential for nature-based solutions (NBS) and nature climate solutions (NCS), as it is home to nearly 15% of the world’s tropical forests and has some of the world’s fastest rates of urban growth. We present a fine-scale urban cluster level assessment for SEA of current (2015) and future (2050) scenarios for carbon sequestration service and climate mitigation potential. We identified 956 urban clusters distributed across 11 countries of SEA. Considering the urban expansion projected and decline in forests, this region could see a carbon loss of up to 0.11 Gigatonnes (Scenario SSP4 RCP 3.4). Comparing carbon change values to urban emissions, we found that the average offset value ranging from −2% (Scenario SSP1 RCP 2.6) to −21%. We also found that a few medium and large urban clusters could add to more than double the existing carbon emissions in 2050 in the SSP3 and SSP4 RCP 3.4 scenarios, while a minority of clusters could offset their emissions under SSP1. Our study confirms that NCS, and particularly reforestation, are in many cases able to offset the direct emissions from land cover conversion from SEA urban clusters. Hence, documenting the plausible LULC transitions and the associated impacts gains significance in the SEA region as the results can be useful for informing policy and sustainable land management.

A large share of urban development in the Global South consists of informal settlements. In addition to multiple everyday risks, informal dwellers face climate-related risks such as flooding and heat waves. Solutions relying on natural infrastructure – greenspace, trees, bioretention systems – increase climate resilience in informal settlements as part of upgrading projects codeveloped with local communities. In addition to addressing hydroclimatic risks, nature-based solutions provide multiple co-benefits such as supporting biodiversity, improving water quality, and increasing quality of life through aesthetic and social benefits. Case studies in Colombia, Fiji, and Indonesia exemplify how natural infrastructure can be implemented in practice, while also highlighting challenges due to data collection and sometimes resettlement of local communities. They pave the way to mainstreaming natural infrastructure considerations in upgrading projects that improve climate resilience in informal settlements.

This article delves into the participatory aspects of the implementation of nature-based solutions (NbS) in the Global South. It examines the practices of community engagement in several projects conducted in informal settlements and how they relate to project visions. Building on previous work on community engagement for urban upgrading projects, we examine the relationship between the methods used to engage communities and the goals that guide the design and implementation of NbS. In doing so, we explore engagement practices that can support the emergence of transformative approaches in historically disadvantaged areas. We discuss how the degree of participation offered by different methods, such as citizen science and serious games, can substantially influence the outcomes of NbS projects by making them more integrated and site-specific. We conclude by discussing how the transformative implementation of NbS entails a multi-stakeholder proactive approach that is capable of supporting changes in the socio-ecological systems.

A large share of urban development in the Global South consists of informal settlements. In addition to multiple everyday risks, informal dwellers face climate-related risks such as flooding and heat waves. Solutions relying on natural infrastructure – greenspace, trees, bioretention systems – increase climate resilience in informal settlements as part of upgrading projects codeveloped with local communities. In addition to addressing hydroclimatic risks, nature-based solutions provide multiple co-benefits such as supporting biodiversity, improving water quality, and increasing quality of life through aesthetic and social benefits. Case studies in Colombia, Fiji, and Indonesia exemplify how natural infrastructure can be implemented in practice, while also highlighting challenges due to data collection and sometimes resettlement of local communities. They pave the way to mainstreaming natural infrastructure considerations in upgrading projects that improve climate resilience in informal settlements.