The Los Angeles region has been ravaged since January 7 by major fires, causing considerable human, material and economic damage, unprecedented in the history of California. These devastating forest fires follow those that have ravaged Australia, Canada, France, and Chile in recent years, the number and intensity of which are symptomatic of the upheavals brought about by global warming. How to explain the scale of the fires in Los Angeles? What are the consequences? How did the authorities react? How to respond to the increase in forest fires on a global scale? The answers from Mathilde Jourde, researcher at IRIS within the Climate, Energy and Security Program.
Violent fires have been ravaging the Los Angeles region for more than a week. What were the main climatic factors causing these fires?
Contrary to the misinformation spread by Donald Trump and relayed on social networks about the deadly (28 dead) and devastating fires still raging in part in California since January 7, the violence of these fires, rare in winter, is mainly the result of factors environmental conditions worsened by human action.
Although winter fires are not entirely unusual in California, this time of year is generally unfavorable for wildfires. However, several converging elements have favored their intensification in this specific case. First, the warm, dry Santa Ana winds characteristic of the winter months played a determining role. These winds reached exceptional speeds, with gusts peaking at 160 km/h, allowing ashes and sparks to spread over great distances, thus increasing the number of fires. Furthermore, the exceptionally high temperatures for the start of winter, coupled with a particularly dry month of January, when it is usually rainy in California, intensified the conditions favorable to the conflagration. The mixture of a windy season and an abnormally dry period therefore explains, in part, the violence of these fires.
Human factors also made the situation worse. Global warming, in particular, has amplified the intensity of fires. Indeed, a little-known phenomenon, the “hydroclimatic whiplash” (whiplash in English), also played a crucial role. This phenomenon refers to the alternation of particularly wet and dry periods. In the case of California, the rainy winters of 2023 and 2024 favored the growth of dense vegetation. However, the lack of precipitation during fall 2024 and winter 2025 made this dry vegetation ideal fuel for fires. According to climatologist Daniel Swain, this phenomenon, which has greatly increased the risk of fire in the region, is expected to increase as the effects of climate change become more felt. Finally, the urbanization and urban sprawl of Los Angeles have increased the city’s vulnerability to fires. Indeed, homes in Los Angeles are often located in the middle of or next to local vegetation, chaparral, which is sensitive and prone to fires, and the flammable materials of the homes make them more exposed to these devastating fires.
What were the consequences of these fires? What responses have been provided by local authorities and the US government?
The Los Angeles fire caused catastrophic social and environmental consequences: 28 deaths, more than 180,000 people displaced and more than 10,000 buildings destroyed. 16,000 hectares of vegetation were devastated, in urban and mountainous areas. In addition to human losses and the direct environmental impact, other less visible consequences are also to be deplored. In particular, the air was heavily contaminated by atmospheric pollutants. In fact, the burned infrastructure released asbestos, copper or lead, toxins representing a significant health hazard for populations. Water has also been contaminated through the air, and through damage to water network infrastructure. The heat from the fires, for example, melted plastic pipes and water meters, releasing dangerous chemicals into the water.
The fire also caused heavy economic losses, with damage estimated at more than $150 billion, potentially making it the costliest fire in modern California, or even the United States, history. Other economic consequences concerning insurance companies are also to be feared. Indeed, over the past two years, certain companies, such as State Farm and Allstate, have suspended or limited their insurance coverage in California due to excessive exposure to numerous risks, such as fires, winter storms or earthquakes. . This fire could thus worsen the current insurance crisis, by encouraging certain companies to adopt new withdrawal strategies. Indeed, the location of the fire, in the heart of a large urban area and in wealthy residential areas, led to insured losses estimated at around $20 billion. As California becomes an increasingly risky market, it also becomes less profitable for insurance companies, making their coverage increasingly uninsurable.
-Finally, the fire also had important political consequences, particularly through its use for partisan purposes. Indeed, the Republican camp has widely resorted to disinformation, with the dissemination of fake newsto weaken California’s Democratic political leaders, and by directing popular anger towards them. For example, Donald Trump accused the Democratic governor of California, Gavin Newsom, of being responsible for the disaster due to a policy of protecting a species of fish, which he allegedly favored over the safety of populations. . For his part, Elon Musk took aim at Kristin Crowley, the Los Angeles Fire Chief, by criticizing the diversity, equity and inclusion (DEI) programs within the city’s fire brigades, holding these programs for those responsible for the ineffective response to the fire. This political co-opting served to divert attention from the root causes of the fire, particularly the role of climate change, while facilitating the marginalization and delegitimization of political adversaries.
To deal with this fire, the authorities’ response was triggered on Tuesday, January 7, when the governor of California proclaimed a state of emergency. According to information provided by the State of California, 8,000 firefighters were deployed to fight the fires, including “incarcerated firefighters” (people incarcerated for minor offenses and trained under a program dedicated to inmates ). The US Army also took part in the intervention, deploying eight US Air Force C-130 Hercules tactical transport aircraft, equipped with the MAFFS II system, a modular, airborne device for dropping water or retardants. The US Navy sent more than 500 Marines, as well as 10 MH-60S Seahawk helicopters equipped with Bambi Buckets, suspended devices designed to drop water. Finally, 2,500 members of the National Guard, a branch of the army specifically trained to respond to natural disasters, were mobilized.
The responses provided, particularly by the federal government, have sparked widespread criticism, with some deeming the management of the crisis inadequate, particularly due to the lack of water supply. A major reservoir in Pacific Palisades, Santa Ynez Reservoir, was notably closed for maintenance and empty at the time of the fire. Some hydrants were also dry at the start of the fire, raising questions about fire preparation and management, as well as the effectiveness of the city’s water infrastructure and services .
United States, Australia, Canada, France, Chile… As fires and climatic disasters have increased in recent years, what preventive or adaptive strategy should be put in place to prevent fires?
Climate change has profound impacts on the intensification and frequency of extreme weather events. Rising temperatures, which favor conditions conducive to forest fires, risk, for example, extending seasons over time. These developments underline the urgency of adopting appropriate strategies, particularly in terms of prevention, to limit the scale of these disasters.
First of all, it is crucial to act through efforts to mitigate environmental impacts, by reducing the carbon footprint, water consumption, and impacts on biodiversity, to slow down the effects of climate change. At the same time, adaptation to climate change in terms of fire risk management is a priority. It is particularly essential to put in place preventive policies, by rethinking the urban model of agglomerations. This involves adapting urban infrastructure and avoiding building or rebuilding in areas with a high risk of fire, through land use planning that moves homes away from vulnerable areas. The use of fire-resistant materials is also essential measures.
Furthermore, a better fire management strategy must also take into account the development of a better operational response during disasters, such as the challenges linked to water management for California for example. Finally, post-disaster management strategies are also essential for rebuilding cities, integrating the need to develop resilience to climate risks.
