#Rio de Janeiro #Brazil #C40 Cities #Extreme Heat #Cool Cities

A Global Movement Against Extreme Heat

In a significant stride towards resilience against the climate crisis, 33 cities from across the globe have come together to form a coalition focused on combatting the dire impacts of extreme heat. This initiative, announced during the C40 World Mayors Summit in Rio de Janeiro, marks the launch of the Cool Cities Accelerator, a program designed to facilitate coordinated action among urban leaders to safeguard their residents and rethink urban spaces in the face of rising temperatures.

As the climate crisis escalates, extreme heat has emerged as the most lethal weather-related hazard, with almost 500,000 deaths annually attributed to it. Without immediate and decisive efforts, the population exposed to perilous urban heat could surge fivefold by 2050. The coalition comprises notable cities such as Austin, Boston, London, and Nairobi, all of whom have committed to implementing strategies to protect their communities and transform city landscapes to adapt to a hotter climate by the year 2030.

A Call for Action

The formation of the Cool Cities Accelerator is supported by esteemed foundations and organizations including The Rockefeller Foundation, ClimateWorks Foundation, and the Danish Ministry of Foreign Affairs. The initiative responds directly to the UN Secretary-General's call for urgent action on extreme heat, aligning with the COP30 Beat the Heat agenda, a pivotal effort aimed at accelerating solutions for local responses to extreme heat and advocating for sustainable cooling practices.

The accelerator brings together cities to share best practices, collaborate on strategies, and report progress in two major areas: immediate actions to protect residents and long-term urban transformation. Within two years, cities will work to establish robust heat leadership, enhance early warning systems, and ensure access to cooling resources during heat emergencies. In a longer timeframe of five years, cities will focus on improving building standards, expanding green spaces, and fortifying infrastructure against extreme heat events.

Examples of Innovative Solutions

Athens, one of the cities facing significant heat challenges, is spearheading efforts to tackle this crisis through a multi-agency approach. The city has implemented a unique heat governance structure, appointing a Chief Heat Officer and advancing projects centered on heat risk communication, the establishment of cool shelters, tree planting initiatives, and urban greening efforts. Their progress demonstrates a proactive stance towards creating a more resilient urban environment.

Elizabeth Yee, Executive Vice President of The Rockefeller Foundation, emphasizes the urgency of this initiative, stating, “Extreme heat is no longer a distant threat; it's affecting the lives and livelihoods of millions globally.” The Cool Cities Accelerator not only addresses immediate climate threats but also lays the groundwork for redesigning urban life, ensuring health systems can handle future climate challenges.

A United Front

C40 Cities, representing nearly 100 mayors, advocates for science-based actions that secure healthier, cleaner futures for urban populations worldwide. The coalition's commitment also includes an impressive $50 million mobilization for adaptation and resilience funding to support communities facing climate risks. This drive reflects a concerted effort to foster collaboration among cities and local organizations, leveraging their unique understanding of community needs to effect meaningful change.

By participating in the Cool Cities Accelerator, these cities signal a collective commitment to setting a global standard for addressing extreme heat through bold and coordinated climate leadership. The initiative serves as a template for other urban areas grappling with similar challenges, paving the way for a cooler, safer, and more sustainable future for generations to come.

To learn more about the Cool Cities Accelerator and the commitment of these cities, visit the official C40 website (active from November 3, 2025).