In 2022, the heat waves that swept across Europe were responsible for over 70,000 excess deaths. But often as countries face heat waves, alarms begin to sound for another escalating climate threat: wildfires. Wildfires, too, have profound public health impacts and have more than doubled across the world. A study in California reported that wildfire smoke increased out-of-hospital cardiac arrests by 70 percent between 2015 and 2017.  

Even more concerning, new research points to the compounding nature of wildfires and extreme heat. As heat waves sweep across several regions, California has faced its largest wildfire of the year, and Greece has battled to contain a rapidly spreading fire in Crete. What could be once considered related but distinct climate-related hazards are now occurring out of traditional weather seasons, creating complex and cascading risks that severely impact the health and wellbeing of vulnerable communities.  

Los Angeles: A tale of two hazards 

On January 7, 2025, fires ignited in Los Angeles. Over 40,000 acres of land was burned and 16,000 schools, homes, businesses, and facilities destroyed. While the story of the wildfires is a sobering climate reality of its own, it also contributes to—and worsens as a result of—climate change and extreme heat.

Marta Segura, the City of Los Angeles Chief Heat Officer and Director of the Climate Emergency Mobilization Office, reflected on the devastating toll of the wildfires. In the weeks following the fires, air quality plummeted to dangerous levels as ash, smoke, and noxious gases blanketed the city. Even miles away from the Eaton fires, tested air samples returned “highly elevated” levels of lead and arsenic. Extreme heat exposure and below average rainfall compound these risks. Segura points out that Los Angeles sees more emergency calls and reports of cardiac-related illness when smoke levels are high during a heat wave.   

While Segura’s core focus is climate resilience, wildfires are inexorably linked to extreme heat. In the summer before the out-of-season Eaton and Palisades fires, for example, Los Angeles faced a prolonged heat season and record-breaking temperatures. Inland temperatures reached 115 degrees Fahrenheit and there were unusually high coastal temperatures. The heat dried out the land, which created dangerously ideal conditions for the ignition and spread of wildfires. When the Santa Ana winds hit Los Angeles at the start of 2025, the flames readily spread. 

Extreme heat and wildfires are increasingly connected. Heat can increase environmental risk and expose communities to more intense and frequent fires. And in turn, wildfires burn down homes that keep people cool and sheltered, ravage urban green space and forests, and release greenhouse gases that accelerate the climate crisis.  

How did the city respond? 

The 2025 Los Angeles fires triggered a coordinated multi-agency response involving federal, state, and local departments. Municipal fire departments in Los Angeles County and the California Department of Forestry and Fire Protection deployed over 16,000 ground and aircraft personnel to contain the fires and direct rapid evacuation orders in high-risk neighborhoods. Networks of local community organizations mobilized to coordinate donations hubs, evacuation transportation, provide temporary shelters and distribute emergency equipment and financial assistance to their communities.  

Beyond these immediate responses, the city has long prioritized building awareness to best prepare communities to identify their risk to climate hazards and respond quickly and efficiently. Los Angeles City and County developed a series of comprehensive policies like the Community Wildfire Protection Ordinance, which aims to reduce wildfire risks to infrastructure and the “Ready, Set, Go!” program with outlines evacuation routes and safety measures in case of an approaching wildfire.  

Los Angeles is also a leading city in coordinated extreme heat preparedness with a heat alert system which reaches Angelenos in Spanish and English. The Climate Emergency Mobilization Office additionally supports the provision of comprehensive infrastructure investments for communities during heat waves including a network of community cooling centers and hydration stations.  

However, the 2025 wildfires have been a direct indication to the city that a more comprehensive multi-hazard approach is essential for disaster preparedness to minimize devastation as the climate crisis surges on. In fact, an analysis of the areas most devastated by the Palisades and the Eaton fires showed a trend of significantly hotter temperatures six months prior to the wildfires. The increase of dual hazards demands a shift in how we respond to weather events by looking at them holistically as more than the sum of its parts. 

What role does extreme heat play? 

While increasing temperatures are not a direct cause for wildfires, they facilitate the conditions that exacerbate the fires’ ignition and rapid spread. Hotter temperatures dry out soil and vegetation, transforming green landscapes into flammable fuel beds.  

But Los Angeles is not the only city facing these dual—and increasingly simultaneous—climate crises. During the 2018 European heat wave, extreme heat and low rainfall led to drought. That same summer, Greece experienced the catastrophic Attica fires, one of the deadliest wildfires in its history. The wildfire itself cannot be directly attributed to extreme heat. However, excessively hot temperatures created conditions where embers easily ignited parched landscapes.

In addition to the devastating damages wildfires inflict on infrastructure, lives, and livelihoods, their ramifications extend far beyond the immediate aftermath. Smoke inhalation, for example, comes with severe, long-term health consequences. One study found that the fine particulate matter released from wildfire smoke is up to ten times more harmful to human health than from other sources of pollution.  

As the world faces more frequent wildfires, stakeholders can learn from cities on the frontlines like Los Angeles. Segura’s office developed a public health guide that featured safety tips for reducing indoor and outdoor smoke exposure following wildfires. Her team also ensured this work went beyond awareness campaigns alone. They coordinated with the Los Angeles Emergency Management Department to deliver air purifiers to local non-profit organizations. In turn, these organizations that were already connected to vulnerable constituents, distributed the units to improve air quality in households. Since the onset of the Pacific Palisades wildfires, CEMO has distributed 1,700 air purifiers with plans to distribute an additional 300 in August 2025. 

Building resilience for a hotter, smokier future 

Public messaging on wildfires and extreme heat falls short of the integrated guidance needed to simultaneously navigate both hazards. In Los Angeles, Segura notes that communications about extreme heat and wildfire smoke risk have been fragmented. Information on protective measures is shared by independently across departments rather than through a unified initiative. Streamlined multi-hazard approaches can reflect the devastating impacts of dual hazards and improve efficiency across departments.  

In Los Angeles, the Climate Emergency Mobilization Office (CEMO) now falls within the City of Los Angeles Emergency Management Department. This will allow CEMO to act as key advisors on compounding climate hazards. Segura is additionally ensuring this is enshrined in city strategy. Her team is incorporating a multi-hazard approach to the city’s first Heat Action Plan. CEMO is emphasizing interdepartmental coordination and more committed resources to holistically address the threat of increasingly compounding climate hazards.  

In the aftermath of the 2025 Los Angeles wildfires, it is clear that we can no longer view climate hazards in isolation. They must no longer be viewed as predictable, seasonal events. The climate crisis blurs the boundaries between these events, placing severe strains on public health, infrastructure, and emergency response systems. To meet this dual risk, municipal and national governments must move beyond siloed approaches and invest in integrated, year-long planning and response frameworks. This includes developing multi-hazard communications, joint response protocols, and implementing preventative measures that address the complex ways extreme heat and wildfires intersect, overlap, and intensify one another.