Extreme heat is one of the most urgent and rapidly escalating consequences of climate change—especially in cities. Urban areas trap heat through dense building materials and paved surfaces, creating dangerous “heat islands” that threaten public health and quality of life. As global temperatures rise and heatwaves become longer and more intense, cities face the critical challenge of staying livable under these harsh conditions.
A growing response has been the creation of a new municipal leadership role: the Chief Heat Officer. From Freetown to Miami, these officials—most of whom are women with backgrounds in public health, sustainability, and urban planning—lead efforts to protect residents by embedding heat resilience into urban policies and projects. They coordinate across agencies and work closely with communities, positioning heat as a central priority in urban planning and design.
While approaches vary city by city, Chief Heat Officers are pioneering the use of innovative materials, cooler building designs, increased shade, and urban greenery. Collaborating with architects, engineers, and planners, they shift urban responses from reactive to proactive—making heat reduction a core goal and creating replicable models for protecting vulnerable populations.
Freetown: Practical Solutions for Informal Markets
In Freetown, Sierra Leone, many residents depend on informal markets for daily commerce—areas often unpaved and exposed to intense heat. Recognizing this, Chief Heat Officer Eugenia Kargbo has implemented community-focused solutions tailored to local realities.
Kargbo led the installation of modular shading structures that reflect sunlight and allow air circulation. These lightweight canopies, made from durable and cooling materials, are customized to each market’s layout. Simultaneously, the city is planting trees to expand natural shade and reduce temperatures through evapotranspiration. Vendors report being able to work longer hours without discomfort, marking a meaningful improvement in daily life.
Santiago: Green Roofs as Climate Infrastructure
Santiago, Chile, focuses on institutional buildings to mitigate urban heat. Chief Heat Officer Patricia Pastén Valdés spearheads efforts to transform rooftops into green, climate-adaptive spaces.
A flagship project at Hospital de Maipú features over 1,000 square meters of green roofing. This system combines waterproof membranes, engineered soil layers, and native or drought-tolerant plants to insulate the building, lower cooling needs, and manage stormwater. The greenery also offers a therapeutic environment for staff and patients.
Santiago is rigorously collecting data from pilot green roofs to evaluate benefits and inform future standards on durability, maintenance, and thermal efficiency. This approach frames green roofs not as optional aesthetics but as essential infrastructure for health, comfort, and sustainability.
Athens: Reflective Surfaces to Lower Urban Heat
Athens, Greece, faces some of Europe’s most extreme urban heat, exacerbated by dark, heat-absorbing pavements. Chief Heat Officer Elissavet Bargianni launched a citywide initiative to apply high-albedo, solar-reflective coatings to sidewalks and pedestrian zones.
Using heat vulnerability mapping that combines environmental and social data, Athens targets areas most in need. Initial results demonstrate that reflective coatings can reduce pavement temperatures by up to 12°C (22°F), improving comfort for pedestrians and lowering heat stress on nearby buildings.
Public works guidelines are being updated to incorporate surface reflectivity as a performance standard, highlighting how thoughtful material choices can significantly enhance urban climate resilience.
Conclusion
Cities worldwide are innovating to combat the escalating threat of urban heat. By embedding heat resilience into design—from shading markets in Freetown, greening rooftops in Santiago, to applying reflective coatings in Athens—Chief Heat Officers are redefining urban planning. Their leadership ensures that heat is no longer a hidden hazard but a visible priority, protecting vulnerable communities and shaping a cooler, more sustainable future.
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