Cities are urgently building resilience to extreme heat
Through shared commitment, cities are deploying emergency heat response systems while transforming urban design
Extreme heat is the deadliest weather-related disaster, contributing to an estimated 489,000 deaths[1] around the world each year. By 2050, the number of city dwellers facing dangerous temperatures could increase by five times the amount. Cities need to improve governance, create early warning systems, and develop cooling infrastructure to safeguard their residents.
Heat doesn’t affect everyone equally. The elderly, infants, outdoor workers, women, people with disabilities, and those in low-income communities face the biggest challenges. These groups often lack air conditioning, live in places with fewer trees, work outdoors in peak heat, and struggle to access cooling centres during emergencies.
The C40 Cool Cities Accelerator unites cities to protect all residents from extreme heat. It focuses on immediate life-saving actions and long-term urban transformation. By joining this Accelerator, mayors are committing to improving resilience through heat governance and emergency response, while ensuring the transition to cooler cities is fair and benefits all communities.
Why cities are prioritising heat resilience
Extreme heat is the deadliest weather-related disaster, contributing to an estimated 489,000 deaths globally each year, and cities are disproportionately affected. Mayors are taking action on extreme heat because protecting communities from rising temperatures requires both urgent response systems and fundamental changes to how cities are built.
Building emergency response systems to protect residents
Early warning systems and cooling centres save lives during heatwaves
Cities are establishing early warning systems, cooling centres, and coordinated emergency protocols to protect residents during heatwaves. Without these systems, communities lack the organised response needed when temperatures spike.
Safeguarding workers and economies from heat stress
Workplace protections maintain productivity as outdoor work becomes dangerous
Extreme heat is projected to cause $2.4 trillion in lost labour productivity by 2030 as outdoor work becomes too dangerous. Cities are deploying workplace cooling solutions and updating regulations to protect construction workers, gig workers, street vendors, and other outdoor workers to maintain economic productivity.
Ensuring cooling infrastructure benefits all communities
Tree canopy and cool roofs in neighbourhoods that need them most
Low-income neighbourhoods often have fewer trees, more heat-absorbing surfaces, and older buildings with poor insulation. Cities are focusing on increasing green cover, cool roofs, and shaded public areas in places that experience the most heat and the least access to adequate cooling.
Future-proofing essential services for higher temperatures
Upgraded design standards keep power, water, and transport running
Power grids, water systems, and transport networks weren’t designed for current temperatures or an increasingly hotter future. Cities are conducting climate vulnerability assessments and updating design standards to ensure energy, water, and transport remain reliable as temperatures continue rising.
What cities commit to through the C40 Cool Cities Accelerator
Cities that sign the C40 Cool Cities Accelerator commit to protecting residents from extreme heat and transforming urban environments to remain liveable as temperatures rise. This Accelerator recognises that cities need both urgent life-saving interventions and long-term design changes. Cities achieve this through two complementary action areas:
Protect: Immediate heat response (within two years)
- Establish heat leadership and cross-agency governance structures with clear coordination protocols.
- Activate heat-health awareness outreach and early warning systems informed by climate data to protect vulnerable communities.
- Deploy cooling solutions during heat emergencies, including designated cooling centres, home and work-based cooling support, and outdoor cooling pop-ups.
Transform: Long-term urban cooling (within five years)
- Update building codes to require safe indoor temperatures sustainably, such as mandating cool or green roofs, improved insulation, or renewably powered active cooling.
- Create networks of cool corridors and public spaces by increasing tree canopy, green cover, and shading, cooling or depaving streets, and deploying water features.
- Future-proof critical infrastructure for rising temperatures by assessing climate vulnerability and implementing design standards for energy grids, water supply, and public transport.
Cities committed to the C40 Cool Cities Accelerator
Accra, Ahmedabad, Amsterdam, Athens, Austin, Barcelona, Bengaluru, Boston, Buenos Aires, Chicago, Durban (eThekwini), Fortaleza, Freetown, Guadalajara, Karachi, London, Melbourne, Milan, Mumbai, Nairobi, New York City, Paris, Phoenix, Quezon City, Rio de Janeiro, Rome, Salvador, Santiago, Singapore, Tel-Aviv Yafo, Tokyo, Tshwane, Vancouver
Questions about the C40 Cool Cities Accelerator?
Cities interested in signing onto the Accelerator or learning more can contact the C40 Cool Cities Accelerator team at heat@c40.org.
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