Paris, Milan and Phoenix Mayors Unite Over Growing Threat of Extreme Heat

By Benson Daniel

The mayors of Paris, Milan and Phoenix are confronting the same increasingly urgent challenge despite their cities being separated by thousands of kilometres: how to protect residents from intensifying heat.

Emmanuel Grégoire of Paris, Giuseppe Sala of Milan and Kate Gallego of Phoenix say rising temperatures are forcing city authorities to rethink how urban areas are designed, managed and protected. Their experiences show that extreme heat is no longer a problem limited to traditionally hot regions but an increasingly serious public health issue across major cities.

Paris has experienced repeated periods of dangerous heat in recent years, prompting authorities to accelerate efforts to create cooler public spaces. The French capital has expanded tree planting, increased shaded areas and worked to redesign streets and public facilities so residents have more protection during heatwaves.

The city is also examining how buildings, schools and other public spaces can remain safe as temperatures rise. Officials have increasingly treated heat preparedness as a public health responsibility, particularly because elderly people, children and those with underlying vulnerabilities face greater risks during prolonged periods of extreme temperatures.

Milan is facing a similar challenge. Sala has backed measures aimed at reducing the amount of heat trapped in the densely built Italian city, including expanding green spaces and improving the urban environment.

The city has also pursued policies designed to reduce pollution and traffic, recognising that the way cities are built and how people move around them can influence both air quality and exposure to heat.

For Phoenix, however, extreme heat is an even more immediate part of daily life. The Arizona city has endured exceptionally high temperatures, with prolonged periods above 100F becoming a recurring threat.

Gallego has pushed measures aimed at helping residents cope with the heat while reducing emissions. These include investments in public transport, cooling infrastructure and technologies designed to lower temperatures on roads and pavements.

The three mayors argue that many of the measures being introduced to tackle climate change also provide immediate benefits for public health.

Planting trees, for example, can provide shade and reduce urban temperatures while also helping cities absorb carbon dioxide. Better public transport can reduce emissions while giving residents alternatives to private vehicles. More resilient buildings can lower energy demand while providing safer indoor environments during heatwaves.

But implementing such policies remains politically and financially difficult.

City governments often have limited resources and must compete for funding with other priorities, while national political decisions can determine whether climate programmes receive adequate support.

The mayors’ experiences also underline a broader shift in the way extreme heat is being viewed. Rather than treating heatwaves simply as environmental events, urban authorities are increasingly approaching them as threats to health, infrastructure, productivity and quality of life.

The challenge is particularly significant because cities tend to trap heat through extensive concrete and asphalt surfaces. Dense development can create urban heat islands where temperatures remain substantially higher than surrounding areas, especially at night.

For Paris, Milan and Phoenix, the response is therefore becoming part of long term urban planning rather than an emergency measure reserved for the hottest days.

The mayors’ shared experience points to a growing reality for cities around the world: adapting to extreme heat will require sustained investment, political commitment and changes to the way urban spaces are designed.