As Los Angeles burned for days on end, horrifying the nation, scientists made an announcement on Friday that could help explain the deadly conflagration: 2024 was the hottest year in recorded history.
The firestorms ravaging the country’s second-largest city are just the latest spasm of extreme weather that is growing more furious as well as more unpredictable. Wildfires are highly unusual in Southern California in January, which is supposed to be the rainy season. The same is true for cyclones in Appalachia, where Hurricanes Helene and Milton shocked the country when they tore through mountain communities in October.
With temperatures rising around the globe and the oceans unusually warm, scientists are warning that the world has entered a dangerous new era of chaotic floods, storms and fires made worse by human-caused climate change.
Wildfires are burning hotter and moving faster. Storms are getting bigger and carrying more moisture. And soaring temperatures worldwide are leading to heat waves and drought, which can be devastating on their own and leave communities vulnerable to dangers like mudslides when heavy rains return.
Around the globe, extreme weather and searing heat killed thousands of people last year and displaced millions, with pilgrims dying as temperatures soared in Saudi Arabia. In Europe, extreme heat contributed to at least 47,000 deaths in 2023. In the United States, heat-related deaths have doubled in recent decades.
“We’re in a new era now,” said former Vice President Al Gore, who has warned of the threats of global warming for decades. “These climate related extreme events are increasing, both in frequency and intensity, quite rapidly.”
The fires currently raging in greater Los Angeles are already among the most destructive in U.S. history. By Friday, the blazes had consumed more than 36,000 acres and destroyed thousands of buildings. At least 10 people were dead, and losses could top $100 billion, according to AccuWeather.
Although it is not possible to say with certainty as any specific weather event unfolds whether it was worsened or made more likely by global warming, the Los Angeles fires are being driven by a number of factors that scientists have linked to fire weather and that are becoming increasingly common on a hotter planet.
Last winter, Southern California got huge amounts of rain that led to extensive vegetation growth. Now, months into what is typically the rainy season, Los Angeles is experiencing a drought. The last time it rained more than a tenth of an inch was on May 5. Since then, it has been the second-driest period in the city’s recorded history.
Temperatures in the region have also been higher than normal. As a result, many of the plants that grew last year are parched, turning trees, grasses and bushes into kindling that was ready to explode.
That combination of heat and dryness, which scientists say is linked to climate change, created the ideal conditions for an urban firestorm.
“Wintertime fires in Southern California require a lot of extreme climate and weather events to occur at once,” said Park Williams, a climate scientist at the University of California, Los Angeles. “And the warmer the temperatures, the more intense the fires.”
A third factor fueling the fires, the fierce Santa Ana winds, which blow West from Utah and Nevada, cannot be directly linked to climate change, scientists say. But the winds this week have been particularly ferocious, gusting at more than 100 miles per hour, as fierce as a Category 2 Hurricane.
Fires across the West have been getting worse in recent years. In 2017, thousands of homes in Santa Rosa, Calif., burned to the ground. The next year, the Camp fire leveled more than 13,000 homes in Paradise, Calif. In 2021, roughly a thousand homes burned near Boulder, Colo.
And from the boreal forests of Canada to the redwood groves of Oregon, large fires have been incinerating vast areas of wilderness.
“In the last couple years we’ve seen an increase in extreme weather events and increasing amounts of billion-dollar disasters,” said Kaitlyn Trudeau, a senior research associate focused on wildfires and the West Coast at Climate Central, a nonprofit research group. “It’s very clear that something is off, and that something is that we’re pumping an insane amount of carbon into the atmosphere and causing the climate systems to go out of whack.”
As the Los Angeles fires consumed some of the most valuable real estate in the world, an unfolding tragedy became fodder for political attacks.
President-elect Donald J. Trump blamed Gov. Gavin Newsom, a Democrat, for the disaster. Mr. Trump inaccurately claimed that state and federal protections for a threatened fish had hampered firefighting efforts by leading to water shortages.
And on Thursday, Elon Musk, the world’s richest man and an ally of Mr. Trump, inserted himself into the debate over the role climate change plays in wildfires.
“Climate change risk is real, just much slower than alarmists claim,” Mr. Musk wrote to his 211 million followers on X, the social media site he owns. He said the loss of homes was primarily the result of “nonsensical overregulation” and “bad governance at the state and local level that resulted in a shortage of water.”
Those claims were rebutted by scientists, who noted that, as humans continue to warm the planet with emissions, extreme weather is becoming more common.
In Los Angeles, residents displaced by the fires watched in exasperation as the unfolding disaster was politicized.
“People are just wanting to blame somebody else,” said Sheila Morovati, a climate activist who lives in Pacific Palisades and saw her neighborhood burn. “What about all the dryness? What about the temperatures? There’s so many pieces that are all pointing back to climate change.”
News that 2024 was the hottest year on record was hardly a surprise. The previous hottest year was 2023. All 10 of the hottest years on record have come in the last decade.
“We sound like a broken record but only because the records keep breaking,” said Gavin Schmidt, director of the NASA Goddard Institute for Space Studies, which monitors global temperatures. “They will continue to break until we get emissions under control.”
But the world is not getting emissions under control. In fact, last year countries released record amounts of planet warming gases into the atmosphere, even as the consequences of climate change have become painfully clear. U.S. efforts to cut emissions largely stalled last year.
The inevitable result: more heat and more extreme weather.
In late September and early October, Hurricane Helene, which scientists said was made worse by climate change, roared across the Southeast, unleashed deadly floods and landslides in several states, including North Carolina.
Months earlier, researchers showed that the devastating floods that swamped Porto Alegre, Brazil, would not have been so severe were it not for human caused global warming.
In May, scientists found the fingerprints of climate change on a crippling heat wave that gripped India, and found that an early heat wave in West Africa last spring was made ten times more likely by climate change.
While Southern California is no stranger to fires, the events of the past week have exposed the region’s inherent vulnerabilities.
As the first fires started, fierce winds pushed the flames through canyons loaded with dried-out vegetation and into homes built in the so-called wildland-urban interface, areas where neighborhoods abut undeveloped wilderness. Both of the areas in the Los Angeles region that suffered the greatest losses, Pacific Palisades and Altadena, were in such fire-prone areas.
Art delaCruz, the chief executive of Team Rubicon, a nonprofit organization that mobilizes veterans and other volunteers to assist after disasters, was at home in Los Angeles when the fires broke out. His house is safe for now, and he is now preparing to deploy volunteers who will help clear roads and distribute aid.
Team Rubicon was founded after a group of former Marines went to Haiti to volunteer after the devastating earthquake in 2010. But Mr. delaCruz said that most of the disasters his organization responds to around the world now are linked to climate change.
“It’s simple physics,” he said. “Warmer air holds more water. The storms are increasing in frequency. The storms are increasing in severity. And the damage is just unbelievable.”
There is no rain in the forecast for Los Angeles for at least another couple weeks. But scientists are already concerned about what will happen when the rains do arrive.
In 2018, the wealthy enclave of Montecito, Calif., just north of Los Angeles, was devastated by mudslides after torrential downpours fell on hills that had recently burned.
“If we get intense rainfall on those burn scars, then we’re going to add insult to injury and have debris flows,” said Alexander Gershunov, a research meteorologist at the Scripps Institution of Oceanography in San Diego.
Heat waves. Drought. Fires. Superstorms. Floods. Mudslides. These are the growing threats of a rapidly warming world, and scientists say nowhere is entirely protected from the effects of climate change.
“We think sometimes that if we live in a city, we’re not vulnerable to natural forces,” Dr. Schmidt said. “But we are, and it comes as a huge shock to people. There’s no get out of climate change free card.”
Lisa Friedman contributed reporting.