Amid a week of horrifying wildfires in Los Angeles, government agencies in the U.S. and around the world confirmed Friday that 2024 was the planet’s hottest year since recordkeeping began in 1880.

It’s the 11th consecutive year in which a new heat record has been set, NASA Administrator Bill Nelson said.

“Between record-breaking temperatures and wildfires currently threatening our centers and workforce in California, it has never been more important to understand our changing planet,” Nelson said.

Firefighters on Friday were battling to protect NASA’s Jet Propulsion Laboratory in La Cañada Flintridge from the Eaton fire, which has burned 13,690 acres and roughly 5,000 buildings thus far.

Research has shown that global warming is contributing significantly to larger and more intense wildfires in the western U.S. in recent years, and to longer fire seasons.

The devastating fires in Southern California erupted after an abrupt shift from wet weather to extremely dry weather, a bout of climate “whiplash” that scientists say increased wildfire risks. Research has shown that these rapid wet-to-dry and dry-to-wet swings, which can worsen wildfires, flooding and other hazards, are growing more frequent and intense because of rising global temperatures.

Extreme weather events in 2024 included Hurricane Helene in the southeastern U.S., devastating floods in Valencia, Spain, and a deadly heat wave in Mexico so intense that monkeys dropped dead from the trees, noted Russell Vose, chief of the monitoring and assessment branch of NOAA’s National Centers for Environmental Information.

“We aren’t saying any of these things were caused by changes in Earth’s climate,” Vose said. But since warmer air holds more moisture, the higher temperatures “could have exacerbated some events this year.”

Last year’s data also notes a step toward a major climate threshold. Keeping the average global surface temperature from rising 1.5 degrees Celsius above pre-industrial levels has long been seen as necessary to avoid many of the most harrowing climate impacts.

NOAA pegged 2024’s global average surface temperature at 1.46 degrees C above its preindustrial baseline, and NASA’s measurements put the increase at 1.47 degrees C. In 2023, NASA said the temperature was 1.36 degrees C higher than the baseline.

Considering the margin of error in their measurements, “that puts the NOAA and NASA models comfortably within the possibility that the real number is 1.5 degrees,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies.

Calculations from other organizations passed the 1.5-degree mark more clearly.

Berkeley Earth and the European Union’s Copernicus Climate Change Service both said the planet warmed to slightly more than 1.6 degrees C above pre-industrial times in 2024. The United Nations’ World Meteorological Organization said the increase was 1.55 degrees C and the U.K. Met Office, the country’s weather service, measured an increase of 1.53 degrees C.

Although 2024 probably marks the first calendar year in which the average temperature exceeded the 1.5-degree threshold, it doesn’t mean Earth has passed the crucial target set in the Paris Agreement, Vose said.

That describes “a sustained, multi-decade increase of 1.5 degrees,” something that’s not expected to occur until the 2030s or 2040s, the scientists noted.

“For a long time, the global mean temperature changes were a bit of an esoteric thing — nobody lives in the global mean,” Schmidt said. “But the signal is now so large that you’re not only seeing it at the global scale … you’re seeing it at the local level.”

“This is now quite personal,” he said.

The oceans, which store 90% of the planet’s excess heat, also recorded their highest average temperature since records began in 1955.

The Arctic has seen the most warming, which is concerning because the region is home to vast quantities of ice that stands to melt and raise sea levels, Schmidt said.

Temperatures there are rising 3 to 3.5 times faster than the overall global average, he added.

The only place where average surface temperatures have cooled is the area immediately around Antarctica, and that’s probably due to meltwater from shrinking ice sheets, Schmidt said.

A year ago, NOAA predicted there was only a 1 in 3 chance that 2024 would break the record set in 2023, Vose said. Then every month from January to July set a new high, and August was a tie. As a result, Friday’s declaration came as little surprise.

The longer-term trends are no better.

“We anticipate future global warming as long as we are emitting greenhouse gases,” Schmidt said. “That’s something that brings us no joy to tell people, but unfortunately that’s the case.”

Times staff writer Ian James contributed to this report.

Even for those lucky enough to get out in time, or to live outside the evacuation zones, there has been no escape from the fires in the Los Angeles area this week.

There is hardly a vantage point in the city from which flames or plumes of smoke are not visible, nowhere the scent of burning memories can’t reach.

And on our screens — on seemingly every channel and social media feed and text thread and WhatsApp group — an endless carousel of images documents a level of fear, loss and grief that felt unimaginable here as recently as Tuesday morning.

Even in places of physical safety, many in Los Angeles are finding it difficult to look away from the worst of the destruction online.

“To me it’s more comfortable to doomscroll than to sit and wait,” said Clara Sterling, who evacuated from her home Wednesday. “I would rather know exactly where the fire is going and where it’s headed than not know anything at all.”

A writer and comedian, Sterling is — by her own admission — extremely online. But the nature of this week’s fires make it particularly hard to disengage from news coverage and social media, experts said.

For one, there’s a material difference between scrolling through images of a far-off crisis and staying informed about an active disaster unfolding in your neighborhood, said Casey Fiesler, an associate professor specializing in tech ethics at the University of Colorado Boulder.

“It’s weird to even think of it as ‘doomscrolling,’ ” she said. “When you’re in it, you’re also looking for important information that can be really hard to get.”

When you share an identity with the victims of a traumatic event, you’re more likely both to seek out media coverage of the experience and to feel more distressed by the media you see, said Roxane Cohen Silver, distinguished professor of psychological science at UC Irvine.

For Los Angeles residents, this week’s fires are affecting the people we identify with most intimately: family, friends and community members. They have consumed places and landmarks that feature prominently in fond memories and regular routines.

The ubiquitous images have also fueled painful memories for those who have lived through similar disasters — a group whose numbers have increased as wildfires have grown more frequent in California, Silver said.

This she knows personally: She evacuated from the Laguna Beach fires in 1993, and began a long-term study of that fire’s survivors days after returning to her home.

“Throughout California, throughout the West, throughout communities that have had wildfire experience, we are particularly primed and sensitized to that news,” she said. “And the more we immerse ourselves in that news, the more likely we are to experience distress.”

Absorption in these images of fire and ash can cause trauma of its own, said Jyoti Mishra, an associate professor of psychiatry at UC San Diego who studied the long-term psychological health of survivors of the 2018 Camp fire.

The team identified lingering symptoms of post-traumatic stress disorder, depression and anxiety both among survivors who personally experienced fire-related trauma such as injury or property loss, and — to a smaller but still significant degree — among those who indirectly experienced the trauma as witnesses.

“If you’re witnessing [trauma] in the media, happening on the streets that you’ve lived on and walked on, and you can really put yourself in that place, then it can definitely be impactful,” said Mishra, who’s also co-director of the UC Climate Change and Mental Health Council. “Psychology and neuroscience research has shown that images and videos that generate a sense of personal meaning can have deep emotional impacts.”

The emotional pull of the videos and images on social media make it hard to look away, even as many find the information there much harder to trust.

Like many others, Sterling spent a lot of time online during the early days of the COVID-19 pandemic. Back then, Sterling said, the social media environment felt decidedly different.

“This time around I think I feel less informed about what’s going on because there’s been such a big push toward not fact-checking and getting rid of verified accounts,” she said.

The rise of AI-generated images and photos has added another troubling kink, as Sterling highlighted in a video posted to TikTok early Thursday.

“The Hollywood sign was not on fire last night. Any video or photos that you saw of the Hollywood sign on fire were fake. They were AI generated,” she said, posting from a hotel in San Diego after evacuating.

Hunter Ditch, a producer and voice actor in Lake Balboa, raised similar concerns about the lack of accurate information. Some social media content she’s encountered seemed “very polarizing” or political, and some exaggerated the scope of the disaster or featured complete fabrications, such as that flaming Hollywood sign.

The spread of false information has added another layer of stress, she said. This week, she started turning to other types of app — like the disaster mapping app, Watch Duty — to track the spreading fires and changing evacuation zones.

But that made her wonder: “If I have to check a whole other app for accurate information, then what am I even doing on social media at all?”