At the forefront of COP28: enhancing urban resilience in cities through Nature-Based Solutions

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World leaders are closing their meetings today at COP28 in Dubai with the aim to increase the climate ambition and action of all countries, and to accelerate the transition to a low-carbon and resilient future. There is no doubt that COP28 has been a crucial conference for the global response to climate change. It has an opportunity to review the progress made since the Paris Agreement and join collective efforts to achieve its goals for the well-being of current and future generations.

The IDB, as the main financing institution for Latin America and the Caribbean (LAC) has been leading the conversation at COP28 in some of the most critical areas for the sustainable development of our region. One of them is the role of the cities in climate change action, and the relevance of incorporating nature-based solutions (NBS) to enhance climate resilience urbanization.

This article, which is part of a series called: “Cities at the Forefront of COP28: Climate Action in Cities in Latin America and the Caribbean” will explore how cities in LAC can strengthen urban resilience to address climate adaptation and mitigation while bringing out broader benefits for biodiversity, communities, and the local economy.

Nature-Based Solutions to Strengthen Urban Resilience

One of the greatest challenges for climate change adaptation is building resilience for the most vulnerable population. LAC is currently one of the regions most exposed to natural disasters impacting 86.6 million people between 2007 and 2014.  The current rate of expansion, lack of planning, land management, and housing strategies are pushing the most vulnerable into informal areas with high vulnerability to climate hazards and disaster risks. According to the IPCC 2022 report, rapid growth in cities has increased the urban informal housing sector (e.g., slums, marginal human settlements, and others), which increased from 6% to 26% of the total residences from 1990 to 2015.

Nature-Based Solutions (NBS) offer multiple advantages for improving the quality of public space and increasing the urban resilience of the most vulnerable areas. These include actions to protect, sustainably manage and restore natural or modified ecosystems, effectively addressing evolving societal challenges and simultaneously providing benefits for human well-being and biodiversity.

NBS can be incorporated into informal settlements through strategies that vary according to the scale of the problem and the specific site conditions where they are implemented. These strategies and actions are aimed at restoring ecosystem services and improving the quality of spaces, utilities, and infrastructure of vulnerable communities at a reduced cost while considering the feasibility of implementation through local means. In this line of research, the IDB recently published a series of monographs called: Ecological Design Strategies for the Vulnerable Cities that proposes to do this through three strategies:

1. Restore and upgrade
2. Adapt and connect
3. Mitigate and anticipate

How can nature-based solutions be used in informal settlements?

The monograph Ecological Design Strategies for the Vulnerable Cities (volume 2 of the series) highlights six typologies of ways NBS can be used in informal settlements to enhance climate resilience:

1. Trees, planted in lines or small clusters. Trees can reduce the heat island effect, regulate air temperature, reduce emissions, improve carbon sequestration, reduce flooding, improve water quality, and enhance biodiversity.
2. Green spaces, parks, gardens, and urban green corridors, which are used to reduce the heat island effect, regulate air temperature, increase carbon sequestration, improve air and water quality, increase and maintain biodiversity, and mitigate the effects of droughts and storm and coastal flooding.
3. Linear green transportation infrastructure consists of the planting of herbaceous plants along transportation structures and/or other types of vegetation such as trees and large shrubs.
4. Rain gardens and floodable parks capture surface runoff, reduce flood risk, store water in times of drought, and filter and purify water.
5. Green terraces, and shallow canals that function as rain gardens.
6. Urban riverbanks and coastal green areas to reduce the overflow and the coastal flooding of urban rivers in times of flooding. Both can help improve water quality, reduce pollution, and contribute to biodiversity improvement.

Curitiba: Innovative Nature-Based Solutions

There are many examples of successful implementation of NBS across the region. For example, Curitiba, the largest city in southern Brazil, is renowned for pioneering urban innovations. Experiencing significant growth from 600,000 in the 1970s to around 2 million in 2020, Curitiba has supported integrated planning, harmonizing land use, housing, and green spaces.

Most recently, the city started one of the largest socio-environmental interventions in Caximba an informal settlement in the southern part of the Tatuquara area located in the flood zone of two crossing rivers and a protected national park. Innovative NBS will be used to address the risk of flooding, control urbanization along the borders of the Environmental Protection Area of Barigui and improve the quality of life of the families. The urban strategy focuses on the city’s green borders and is based on flood management, creating multifunctional hubs for social-cultural exchange at the urban-green borders, and affordable urbanism based on the sites & services model for planning irregular urban developments. The mixed-use plots will have affordable housing, collective spaces, and areas for agriculture. Community involvement is supported by urban agriculture, self-construction programs for housing, and three multifunctional community centers at the intersection of transportation routes and natural areas. These include libraries, healthcare facilities, sports facilities, administrative centers, and local markets.

Additionally, there is an ongoing solar project using photovoltaic cells (PV) on a deactivated landfill site in Caximba.

Download the Ecological Design publication series

There is little knowledge of implementable solutions and the important benefits of nature-based solutions in informal settlements. In many cases, the lack of appropriate political, regulatory, and technical conditions blocks both public as well as private investment. This is even more relevant in informal settlements that are frequently left out of municipal or government plans and have extremely limited or non-existent investment potential of private investment in the public realm.

The Ecological Design Strategies series of the IDB provides best practices that have been implemented in the region, policies, and projects that can improve the resilience of the most vulnerable settlements and integrate them into future urban visions so that decision-makers have better guidance.  You will learn and enjoy reading them!