Building climate-resilient cities
Unprecedented climate-induced extreme weather events are already unfolding across our cities.
Water-related hazards account for 90% of global disasters, with rapid swings between severe drought and torrential rain pushing urban infrastructure to its limits. By 2050, 7.4 million residents across C40 cities will face severe annual river flooding, causing USD 64 billion in yearly damages. At the same time, record-breaking temperatures threaten lives everywhere. Globally, extreme heat claims over 500,000 lives annually, and heat stress alone threatens USD 2.4 trillion in economic losses by 2030. Nearly 100% of C40 cities face severe climate threats that endanger public health, businesses and communities.
These impacts hit frontline communities hardest, including low-income neighbourhoods, outdoor workers, older adults and young people. By acting with urgency and accountability, C40 mayors are delivering proven measures to protect their communities.
They are redesigning streets, expanding green spaces and upgrading city infrastructure to make cities safer, cooler and more resilient.
Why urban climate resilience is critical
Building climate-resilient cities is essential to protecting lives, economies and infrastructure as climate impacts accelerate.
Protecting vulnerable communities
Climate hazards hit low-income residents and marginalised groups hardest. Resilience ensures climate protections reach those who need it most.
Safeguarding public health and safety
Urban heat islands, dangerous flooding and water scarcity directly threaten lives. Targeted adaptation measures, such as cooling networks and flood defences, reduce weather-related deaths and emergency hospitalisations.
Securing economic and infrastructure stability
Extreme weather destroys infrastructure, disrupts supply chains and threatens local businesses. Resilience protects investments and reduces long-term recovery costs.
Creating thriving, liveable urban spaces
Resilience measures like tree planting, rain gardens and depaved streets cool local temperatures, improve air quality and urban drainage, and expand green spaces for everyone.
Connecting local delivery to global goals
City-level adaptation translates immediate local climate risks into targeted, on-the-ground action, demonstrating proven, scalable resilience solutions.
How C40 supports cities with local adaptation
Cool Cities Accelerator
See how C40 cities are protecting residents from extreme heat through cooling strategies and climate adaptation plans.
Water Safe Cities Accelerator
Learn about how C40 cities are committing to protect at-risk communities from flooding and drought through early warning systems, emergency response plans, and transformative water management solutions.
Urban Nature Accelerator
Join cities committed to expanding nature in urban environments to build climate resilience and create healthier, more equitable communities.
How C40 cities are taking action
Cities are already delivering proven, measurable adaptation solutions on the ground:
Freetown
Freetown is planting over 1 million trees to cool neighbourhoods, prevent dangerous landslides and protect vulnerable areas, and 65 water kiosks are improving water security and ensuring residents have consistent access to clean water.
See how Freetown is working hand-in-hand with community members to address extreme heat, flooding and water security.
Paris
Paris did 50°C stress-test exercises across schools, nursing homes and public services to evaluate citywide emergency responses to extreme heat.
In 2026, Paris experienced numerous record-breaking heatwaves. See how the city worked to adapt, keep residents safe, and provide creative solutions for cooling down.
Quito
Quito strengthened its emergency water supply management by training local Community Risk Management Committees (CRMCs) and installing portable bladders to ensure fair, reliable water access to over 5,500 people daily.
São Paulo
São Paulo built 229 rain gardens equal to 90,000 m² to manage heavy stormwater runoff and create urban mini-ecosystems.
Fuzhou
Fuzhou deployed China’s first city-level integrated flood platform to automatically manage over 1,000 water infrastructure assets during storm surges.
Quezon City
Quezon City implemented multi-hazard early warning systems (iRise UP) using real-time data and risk mapping to protect frontline communities. Zero weather-related casualties have been recorded since implementation.
New York
New York implemented pop-up cooling stations that offered misting, shade, and cool kits to outdoor workers, who are especially vulnerable to extreme heat.
Funders and strategic partners
Supporting climate resilience across C40 cities
C40 works in collaboration with leading global partners to make cities more resilient to climate hazards. Previous support for this work was provided in part by the Robert Wood Johnson Foundation.
![Z Zurich Foundation [funder] logo](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAxMDI0IDY1NSIgd2lkdGg9IjEwMjQiIGhlaWdodD0iNjU1IiBkYXRhLXU9Imh0dHBzJTNBJTJGJTJGd3d3LmM0MC5vcmclMkZ3cC1jb250ZW50JTJGdXBsb2FkcyUyRjIwMjMlMkYxMSUyRlNjcmVlbnNob3QtMjAyMy0xMS0xMC1hdC0wOS41NS40MS0xMDI0eDY1NS5wbmciIGRhdGEtdz0iMTAyNCIgZGF0YS1oPSI2NTUiIGRhdGEtYmlwPSIiPjwvc3ZnPg==)
Frequently asked questions
How are mayors successfully leading on climate resilience?
Mayors are establishing multi-hazard early warning systems, depaving streets, expanding urban shade, upgrading drainage networks, and coordinating city departments to protect vulnerable residents.
What is urban climate adaptation?
Adaptation refers to actions that protect cities and residents from climate shocks and stresses. Key priorities for C40 cities include mitigating extreme heat, managing flood risks, and ensuring water security.
What is El Niño and how does it impact cities?
El Niño is a recurring climate pattern that disrupts global weather, intensifying extreme heat, drought, heavy rainfall and flooding. While a natural process, the climate crisis amplifies El Niño’s risks, posing severe threats to public health, food security and water access.
Related
How cities plan and design urban space shapes climate outcomes and quality of life. C40 helps mayors develop bold strategies, regulations, and projects that enable urban regeneration and growth.
Cities are fighting the climate crisis: protecting people today with warning systems and heat plans, while building long-term resilience with nature to secure water, reduce flooding, and cool urban spaces.
Access insight and advice to deliver effective climate action in your city on our Knowledge Hub platform. The Knowledge Hub is a public resource for all cities globally, including cities that are not members of C40.
