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USA Today
29-01-2025
- Climate
- USA Today
'Hotter, drier, and more flammable': Scientists say climate change fueled LA fires
A rapid analysis of the devastating Los Angeles County wildfires concluded that while climate change didn't directly cause the fires, it intensified dangerous conditions and made the fires more likely. In a report released by World Weather Attribution on Tuesday evening, a group of 32 international researchers used its peer-reviewed rapid assessment method to evaluate how climate change fueled the firestorm. The two largest blazes, the Palisades and Eaton fires, killed 29 people, torched more than 40,000 acres and destroyed more than 16,000 structures. The still unidentified ignition sources that sparked the blazes brought together a hazardous set of conditions all at once, said Park Williams, a professor in the geography department at the University of California Los Angeles. That included more extreme than usual Santa Ana winds, a delayed start to the rainy season, and an abundance of dried out plants and shrubs that had grown vigorously from rainier-than-normal conditions over each of the the two previous years. Climate change amplified those conditions, Williams said. In effect, it was like someone flipped on four light switches all at once and "climate change is making the light brighter." A fire weather index showed the strong winds and incredibly dry conditions that led to the fires have been made about 35% more likely than they would have been in the late 1800s, when average temperatures were about two degrees cooler than in the current climate, said Clair Barnes, a World Weather Attribution researcher at the Centre for Environmental Policy at the Imperial College London. 'The next Maui could be anywhere':Hawaii tragedy points to US wildfire vulnerability A prolonged dry season like the one that occurred between October and December is now about 80% more likely, Barnes said. Researchers also concluded the length of California's dry season has increased by about 23 days. This means the dry season and the warm Santa Ana winds that spread fires are increasingly overlapping, the authors stated. 'Drought conditions are more frequently pushing into winter, increasing the chance a fire will break out during strong Santa Ana winds that can turn small ignitions into deadly infernos," the study reported. Although pieces of the analysis are accompanied by degrees of uncertainty, the researchers said the trends all point in the same direction ‒ that climate change increased the likelihood of the fires. 'Without a faster transition away from planet-heating fossil fuels, California will continue to get hotter, drier, and more flammable," Barnes stated. World Weather Attribution pointed out that climate change is having a similar influence on wildfires in many regions of the world, as hot, dry conditions increase the risks. Both the Palisades Fire and the Eaton Fire, which started on Jan. 7, are now more than 95% contained, according to the Los Angeles County Fire Department and the California Department of Forestry and Fire Protection. So far, the ignition sources behind the two fires have not been identified. Power lines and wildfires:Experts say communities can be better protected, at a high cost The report's authors made two other points regarding potential factors blamed for wildfires. Once the fires reached into neighborhoods, putting out the blazes grew even more challenging because the community's water infrastructure, such as the fire hydrant system, is designed for routine structural fires and not the sort of unprecedented and continuous needs posed by these fast-moving fires, said Roop Singh, a climate risk advisor at the Red Cross Red Crescent Climate Centre, based in The Netherlands. "As the likelihood of extreme fire weather conditions increases with climate change," she said, communities will need more robust water systems to carry more water farther. The dramatic switch between wetter-than-normal weather to drier-than-normal conditions is a phenomenon becoming more extreme in the warming climate, the report's authors said Tuesday. Calling it weather whiplash, the report refers to a study published in the journal Nature Reviews the same week the fires began, led by Daniel Swain, a climate scientist with UCLA and the University of California Agriculture and Natural Resources. Swain has said the "hydroclimate whiplash" in California has increased fire risk twofold: "First, by greatly increasing the growth of flammable grass and brush in the months leading up to fire season, and then by drying it out to exceptionally high levels with the extreme dryness and warmth that followed." Evidence shows this whiplash has "already increased due to global warming," Swain said, "and further warming will bring about even larger increases." Dinah Voyles Pulver covers climate change and the environment for USA TODAY. She's been writing about wildfires since the Florida firestorm of 1998. Reach her at dpulver@ or @dinahvp on X or Bluesky.
Yahoo
28-01-2025
- Science
- Yahoo
Climate change made the deadly Los Angeles wildfires more likely. And, the worst is yet to come
The devastating wildfires that resulted in the deaths of 29 Californians this month were made more likely due to the impact of climate change, researchers said Tuesday. The blazes were worsened by dried-out vegetation, low rainfall in the region and the overlap between drought conditions and hurricane-force Santa Ana winds, according to the group World Weather Attribution. 'Without a faster transition away from planet-heating fossil fuels, California will continue to get hotter, drier, and more flammable,' Dr. Clair Barnes, a researcher at England's Imperial College London, said in a statement. The international research published Tuesday found that the hot and dry conditions that drove the recent fires were about 35 percent more likely due to warming caused primarily by the burning of oil, gas and coal that releases atmosphere-warming greenhouse gases. These tinderbox conditions will become 35 percent more likely with 2.6 degrees Celsius (4.7 degrees Fahrenheit) of global warming relative to preindustrial levels. Under recent pledges to take climate change, a United Nations report found that temperatures would still rise by that much or more by the year 2100. After months without rain, Southern California finally saw downpours and snow this week. But, low rainfall between the months of October and December, the study said, is now about 2.4 times more likely compared to the preindustrial climate. In addition, hotter temperatures are evaporating more moisture from plants, making them easier to burn. 'All the pieces were in place for a wildfire disaster – low rainfall, a build-up of tinder-dry vegetation, and strong winds,' Park Williams, a professor of geography at UCLA, explained. To determine how climate change may have played a role in promoting the late-year fire weather, researchers combined weather data with climate models. But the models did not perform well due partially to the small and mountainous study area and sparse rainfall, World Weather Attribution noted. They indicated that there was an influence on hot, dry and windy conditions, but did not show a significant impact on rainfall on the fire season's end date. Still, scientists said they were confident that climate change is an important driver of the changes, citing existing research and real-world data. 'In 2025, the choices facing world leaders remain the same – to drill and continue to burn oil, gas and coal and experience ever more dangerous weather, or transition to renewable energy for a safer and fairer world,' Dr. Friederike Otto, World Weather Attribution's co-lead and Senior Lecturer in Climate Science at Imperial College London, said.
Yahoo
28-01-2025
- Climate
- Yahoo
Conditions that fueled L.A. fires were more likely due to climate change, scientists find
Climate change increased the likelihood of the extreme conditions that allowed the recent fires to roar across the Los Angeles area, an international group of scientists said Tuesday. The hot, dry and windy conditions that preceded the fires were about 35% more likely because of human-caused global warming, according to a new report from the World Weather Attribution group, which analyzes the influence of global warming on extreme events. The fires, which started during a ferocious windstorm and after almost no rain had fallen in greater Los Angeles since the spring, have killed at least 29 people and torched more than 16,000 buildings, including homes, stores and schools. 'This was a perfect storm when it comes to conditions for fire disasters — the ingredients in terms of the climate enabling, the weather driving the fires and the huge built environment right downwind from where these ignitions occurred,' John Abatzoglou, a professor of climatology at the University of California, Merced, who contributed to the report, said at a news conference. Compared to a preindustrial time before fossil fuels were widely used, there are now 23 extra days of 'dry season' on average each year in the Los Angeles region, the report said, making it more likely that fires will coincide with seasonal Santa Ana winds. Park Williams, a professor of geography at the University of California, Los Angeles, and an author of the report, said fires during cool seasons in Southern California require four conditions: widespread grass or brush that can burn; abnormally dry conditions; an ignition (which almost always comes from a person); and extreme weather, like the recent windstorm. He described each of these conditions as an individual switch in a system that requires all four to be flipped on in order for light to emanate. 'The artificial warming due to human-caused climate change is making the light brighter,' Williams said. The authors of the report analyzed weather and climate models to evaluate how a warmer atmosphere is shifting the likelihood of fire weather (meaning conditions that increase the risk of wildfire). They also tracked how a metric called the Fire Weather Index changed over time. The index tracks temperature, relative humidity and wind speeds, all factors that contribute to the likelihood of fire. The researchers found that the kind of conditions that drove the L.A. area fires are expected to occur on average once in 17 years in today's climate. Such conditions would have been expected once every 23 years without climate change and would have been less extreme when they did occur, the report says. As a group, World Weather Attribution is a loose consortium of scientists who publish rapid findings about climate change's role in extreme weather events. Although their research methods are peer-reviewed, this specific rapid analysis has not been through the rigor of a typical academic review process, which can take months or longer. The group's prior analyses of heat, wildfire and hurricane disasters have held up to scrutiny after initial release and were ultimately published in academic journals. For climate attribution scientists studying how much climate change is to blame for specific events, wildfire disasters are notoriously challenging to untangle, and local nuances are extremely important. In the case of the recent California fires, the report's authors found that although climate change played a role, it was not the sole factor. The hillsides surrounding Los Angeles are filled with brush that has evolved to burn with regularity, and more people are in these areas today than in the past to potentially start fires via cigarettes, power lines, fireworks, vehicles or other sources. Additionally, neighborhood development has pushed deep into areas prone to burn, which means houses are serving as fuel for wildfires and contributing to its rapid spread. 'Fire in Southern California is highly complex, right? It's a combination of a number of things. This is a landscape that's got a really distinct human imprint on it,' Abatzoglou said, adding that the Los Angeles region has 'a large population, a lot of ignitions, a lot of land-use related issues.' The influence of climate change on the Santa Ana winds, one of the driving factors behind the Los Angeles fires, remains murky. The report's authors said that some research suggests the winds will become less intense as the climate warms; however, other research suggests this wind pattern will persist and perhaps intensify during the cold months. 'We don't know of a direct mechanism that would link climate change to the winds, but there could be," Williams said. "We just don't know." This article was originally published on
