As record-breaking heatwaves swept across Europe and the U.K. in summer 2024, including one that disrupted London Climate Action Week, the mayors of Paris, Milan, and Phoenix convened in London to exchange methods on managing extreme heat events.
Each city faces the challenge of protecting residents as temperatures rise and heatwaves become increasingly regular. Paris and Milan, historic European cities, are now adapting infrastructures designed for cooler climates, while Phoenix, located in the Arizona desert, has been managing extreme heat for decades and serves as a model for heat resilience strategies.
Innovative Measures in Phoenix
Phoenix has developed some of the world’s earliest dedicated city offices focusing on heat mitigation and response. Their approach combines immediate relief for vulnerable populations with long-term cooling efforts like maintaining 75% shade coverage in new high-foot-traffic developments, applying cool surface treatments to over 300 kilometers of streets, and running 24-hour cooling centers connecting residents to housing, medical, and employment resources.
Policies mandated by law require landlords to maintain indoor temperatures at or below 82 degrees Fahrenheit. Additionally, companies contracted by the city must implement heat safety plans for workers, measures credited with a 20% decrease in heat-related emergency calls in the 2024 summer, Phoenix’s hottest on record.
Adapting Historic Cities: Paris and Milan
Paris has established more than 1,400 “cool spots” accessible within a seven-minute walk for every resident during heatwaves. The city extends opening hours for parks, pools, and baths during high temperatures and mobilizes 27,000 climate volunteers to educate communities on heat adaptation.
In October 2023, Paris organized a preparedness exercise simulating a 122-degree Fahrenheit heat scenario to improve municipal response and planning, inspiring Barcelona to implement a similar drill.
Milan is expanding its Piazze Aperte program by adding green, shaded spaces and permeable surfaces to existing open squares and school streets, aiming to lower urban temperatures. The city’s Air and Climate Plan ambitiously targets limiting local temperature increases to 2 degrees Celsius by 2050, illustrating a strong climate commitment.
Shared Challenges and Global Collaboration
Extreme heat is the deadliest climate hazard worldwide, claiming over half a million lives annually. Urban environments worsen heat risks due to the heat island effect, which traps warmth overnight, leaving vulnerable groups such as elderly residents, children, outdoor workers, and lower-income populations at higher risk.
The mayors emphasize that while cities must tailor solutions to local contexts, sharing effective strategies through networks like C40 Cities is vital. Such global collaboration accelerates the implementation of successful initiatives for cooling public spaces, worker safety, and public communication.
Calls for National Support
The leaders urge national governments to empower cities with greater funding, legal authority, and flexibility to enact heat adaptation strategies and expand early warning systems. Investments in renewable energy and cleaner heating and cooling systems can reduce emissions, improve air quality, create jobs, and ensure equitable benefits.
As extreme heat shifts from an occasional hazard to a recurrent summer threat, the mayors stress that it represents a political crisis demanding bold, coordinated action to protect millions and redefine urban living in a warming world.
