Key messages
- Few cities include effective mitigation and adaptation strategies in their action plans, even though climate-related risks are predicted to impact billions living in cities.
- Climate-resilient development can be operationalised more effectively with a social-ecological-technological systems (SETS) approach. Smart solutions and technologies can facilitate the adoption of the SETS approach, ensuring co-benefits and minimising trade-offs.
- Cities in various stages of development — emerging, rapidly growing, established, and shrinking — face distinct challenges posed by climate change, requiring tailored development strategies for each context.
As climate change intensifies, billions of people in cities around the world will be at risk of climate-related hazards. Many are already dealing with the impacts of the climate emergency. Around 80 of the 100 fastest growing cities in the world, which are also classified at high risk of climate change, are in Asia and Africa and include commercially important capitals such as Jakarta, Lagos and Addis Ababa. Systemic challenges, such as out-migration leading to shrinking cities and the ageing of populations, can reduce residents’ ability to withstand and adapt to, and rebuild after extreme events.
While both mitigation and adaptation efforts are imperative to integrate into cities’ planning and actions, local governments often have to prioritise one over the other according to available budgets and funding. Imbalanced considerations and actions can lead to suboptimal outcomes and trade-offs between mitigation and adaptation. With climate action at its core, and a focus on ensuring vulnerable populations are not left behind, climate-resilient development fitted with a social-ecological-technological systems (SETS) approach supports sustainable development in an integrated manner. This approach can help cities to implement local-level climate action within a broader sustainable development agenda.
Systems approaches that consider cities as dynamic and open can help decision-makers to identify and minimise trade-offs that can be missed or exacerbated when isolated or bilateral measures are taken. The SETS approach examines interactions and interdependencies, broadening the spectrum of intervention options and the potential for co-benefits, for example in adaptation, mitigation, biodiversity, health, equity and more. As an example, cities have recorded high heat-related deaths and illnesses in recent years. Socio-economically disadvantaged neighbourhoods with less greenery are hit hardest, and own fewer cooling facilities. Additionally, both rural and cross-boundary migration in some cities has drawn poor households to informal settlements in hazard-prone areas, of which recurrent climate impacts, such as floods, lead to a poverty trap, increasing vulnerability and inequality in society. Yet, when new green space programmes do not consider this social-ecological-technological interplay on heat vulnerability, they may allocate the cooling benefits disproportionately in wealthier neighbourhoods or lead to gentrification, further intensifying inequality in adaptation. Air conditioning, while important for adapting to extreme heat and saving lives, is energy-intensive, emits heat and GHGs, creating feedback loops through heat exhaust, and is often unaffordable. The SETS framework applied to this case illustrates the advantages of integrating various dimensions to generate holistic solutions (Figure 8). Ecological strategies like green and blue infrastructure, and social measures such as behavioural interventions, can help reduce the need for air conditioning while mitigating heat-health risk. This integration minimises trade-offs and maximises co-benefits, fostering more resilient and liveable cities.
Fast-growing cities in low- and middle-income countries need support to develop critical green and blue infrastructure. These cities often lack socio-economic capabilities or adaptive governance mechanisms, especially those with informal structures. Smaller cities can also lack climate-related funding streams and rely quite heavily on central government budgets, which delays planning processes.
Overall, innovative mechanisms that encompass all components of SETS are better suited to deal with trade-offs and conflicts. In doing so, cities can move towards climate-resilient development based on transformative decisions.
Policy implications
- Momentum for a more central role of cities in global climate action has been growing since COP26. At COP28, the Coalition for High Ambition Multilevel Partnerships (CHAMP) and the Joint Outcome Statement on Urbanization and Climate Change, focused on empowering cities and local governments to strengthen climate action through multilevel collaboration. In particular, these efforts push for the incorporation of stronger urban content into Nationally Determined Contributions (NDCs).
- An integrated social-ecological-technological systems (SETS) approach can serve as a guide for operationalising urban climate-resilient development, enhancing co-benefit and prioritising synergistic solutions that enable local adaptation to climate change impacts while contributing to global efforts to reduce GHG emissions. This resonates strongly with the COP29 Presidency initiative on Multisectoral Actions Pathways (MAP) Declaration for Resilient and Healthy Cities. Intervention highlighted in the literature include:
- Green infrastructure and solar passive building designs coupled with new behavioural norms on dress codes, for example, reduce heat stress, as well as GHG emissions from building operations.
- Urban planning and governance supported by big data analytics and AI tools to maximise co-benefits and minimise trade-offs. AI-supported decision-making enables far more powerful assessment of multiple interactions across various social-ecological-technological components of the urban system.
- Invest in improved capacities for adaptive governance and transformative urban planning.
- Build innovative institutional partnerships that include local communities and the private sector to improve implementation and management of urban infrastructure and services.
- Interventions for managing climate risks must be designed to respond to the specific ecological and vulnerability contexts of the city. Strategies and solutions must be tailored to the unique challenges faced by cities at different stages of their development, whether emerging, rapidly growing, established, and/or shrinking.
- Policy interventions must recognise and address socio-economic inequities and entrenched vulnerabilities because of past urban planning legacies, present informal settlements at high-risk areas, and new policies leading to green climate gentrification. This will prevent reinforcements of injustices and maladaptation.
- Multi-level and multi-actor capacity development strategies and programmes that address the need for adaptive local governance in the context of growing uncertainties and rapid urbanisation are needed, particularly in low- and middle-income countries.
- Build innovative institutional and partnership strategies that include local communities and the private sector to improve implementation and management of urban infrastructure and services.
Illustrated solutions to urban heat using a SETS approach (McPhearson et al. 2022) compared to conventional (one-dimensional or two-dimensional) approaches, to guide planning and integrate policies with co-benefits from positive interactions among interventions (as indicated in the top right corner).
