EOS

From Devastation to Data

Over 24 days in January, the Eaton and Palisades fires burned nearly 38,000 acres of Los Angeles County. Whole neighborhoods were destroyed, 29 people died, and thousands were displaced. The conditions that led to the fires were estimated to be 35% more likely because of climate change, and damage to public and private infrastructure made the blazes among the costliest wildfire disasters in U.S. history.

In the wake of the fires, multiple local, state, and federal disaster response agencies mobilized to contain the flames, document dangers, and communicate those findings to the public. Agencies’ emergency response playbooks are tried and tested and often require interagency cooperation.

Within this massive, coordinated effort in postfire monitoring and response, where have non-agency scientists with relevant skills and a desire to help fit in?

This is a question Michael Lamb has wrestled with this year. Lamb is a geomorphologist at the California Institute of Technology (Caltech) in Pasadena who was evacuated from his home and left without power for several days when the Eaton Fire tore through Altadena.

Lamb, who researched debris flow patterns after the 2009 Station Fire in the Angeles National Forest, wondered how to apply his knowledge to help with this latest disaster, and whether he should. He worried that members of his lab group, by inserting themselves into the disaster response apparatus, might inadvertently confuse official communications or make it harder for first responders to do their jobs.

“We don’t want to take time away [from agency scientists], especially when they’re in the middle of the emergency management part of work,” Lamb said.

Lamb wasn’t alone in his concern, or in his desire to help. The areas of Los Angeles County affected by the Palisades and Eaton fires are home to a high concentration of scientists who work or study at the area’s many scientific institutions. Some of them study fires and fire impacts and realized they could help, while many outside that niche were surprised to find that their work might have new, immediate applications close to home.

Scientists Spot Need

When the Palisades Fire was still burning in early January, Adit Ghosh watched the coverage at home on television. Ghosh, an Earth science graduate student at the University of Southern California (USC) in Los Angeles, had helped evacuate his in-laws and some of his friends from at-risk areas and couldn’t go in to work because campus was closed.

“They were showing the fires nonstop,” Ghosh recalled of news reports. In one broadcast, the camera zoomed in on a house in Mandeville Canyon near Topanga State Park. “I saw it on TV catching fire and then burning to the ground.”

“He took us to this house. Then it clicked. This is the house that I saw burning on TV.”

By the third week in January, Ghosh was back in his geochemistry class. His adviser, who works closely with the professor teaching the course, suggested a way for Ghosh and his fellow graduate students to contribute to the ongoing efforts to understand contamination in water runoff. They were eager to help in whatever ways they could.

That weekend, Ghosh went out with a team of other USC students to collect water runoff in burned areas. They hoped to analyze the samples for chemicals that might prove harmful to human and environmental health. A helpful resident showed the team around the burned area, pointing out places they might collect samples from.

A home burned by the Palisades Fire. Credit: Adit Ghosh

“He took us to this house,” Ghosh said. “Then it clicked. This is the house that I saw burning on TV.”

The postfire landscape and environmental conditions can change rapidly. Many scientists felt a sense of urgency to collect samples of ash, dust, soil, and water, as well as to study sediment and debris built up along the mountainside, because much of these data are considered “perishable,” Lamb explained.

In an area burned by the Palisades Fire, a University of Southern California student collects water runoff from a drainpipe. Credit: Adit Ghosh

Lamb’s team rushed to obtain flight permits and conduct drone flyovers of debris channels along the San Gabriel Mountains above Altadena. Knowing that weather reports anticipated rain soon after the fires, debris flow researchers wanted to obtain postfire, prerain lidar scans of the channels’ topographies to better understand how debris accumulates and what conditions can trigger dangerous flows.

If measurements weren’t taken quickly enough, information about immediate postfire impacts could be washed away. They shared their results with disaster response agencies and affected communities.

Serendipitous Science

In the wake of such a disaster, doing something, anything, to help others can be a powerful tool of healing and recovery.

“As soon as they were safe, people really wanted to contribute,” said Kimberley Miner, a climate scientist and representative of NASA’s Disasters Response Coordination System (DRCS) at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif. NASA and JPL coordinated to fly the Airborne Visible/Infrared Imaging Spectrometer 3 (AVIRIS-3) instrument to survey damage immediately after the fire.

The first AVIRIS-3 flight on 11 January was serendipitous, explained Robert Green, principal investigator for AVIRIS-3 at JPL. The instrument had already been installed on a plane and approved to fly over a completely different area. The team was able to divert the flight path to cover the Eaton burn area instead.

“There were folks working out of hotel rooms [on all of that imagery] while they were evacuated.”

“There were folks working out of hotel rooms while they were evacuated,” Miner said. On some science teams, only one or two people had not been displaced.

The AVIRIS team has been on the scene after some of the most infamous disasters in modern U.S. history. The team flew an earlier version of the instrument over the ruins of the World Trade Center after the terrorist attack on 11 September 2001 to look for asbestos and residual hot spots burning under the rubble. After the 2010 Deepwater Horizon disaster, AVIRIS-3 data yielded the first estimates of how much oil had been released into the Gulf of Mexico.

Even in the context of those disasters, Green said that flying over the L.A. burn scars was “heartbreaking and poignant.”

“It’s especially poignant, I would say, because it is a local disaster,” Green said. “But for 9/11, the Gulf oil spill, or wherever we contribute, our team is committed to offer information via this unique spectroscopy to be helpful.”

The first AVIRIS-3 flyover provided some of the first aerial data assessing the scope of the fires. NASA’s DRCS provided those data to federal and state disaster response teams, and those data helped justify and expedite approval for subsequent flyovers.

Getting Involved but Not Being in the Way

As official emergency responders worked to contain the fires and rapidly document the damage, collecting samples from the air, ground, rivers, or ocean outside of those efforts presented logistical quandaries.

The USC team that Ghosh worked with to collect water runoff samples had been organized within his department and went out on its own volition. But getting to sample sites was a challenge.

“We’re trying to focus on whatever we can get our hands on, essentially, because access is really hard,” he said earlier this year. In some burned areas where runoff sampling would have yielded important science results, for example, the National Guard had restricted access to prevent looting.

“Even in sites that are open, the residents still didn’t really want us hanging around over there. And understandably, because their house almost burnt down,” Ghosh said. When members of his team encountered resistance from residents, he said, they respectfully moved to another location.

“Something that we can try to help with more as research scientists is to think about real forward-looking measurements.”

Lamb said that his research group considered a broad range of science that they might contribute before contacting government agencies operating in the area. “We reached out via email to people…leading debris flow hazard teams and just said, ‘We are interested in helping. These are some of the capabilities we have. We also don’t want to get in the way. Please let us know if this can be of help.’”

Lamb’s team was told it could help by monitoring the accumulation of sediment and debris in ravines on the slopes of the San Gabriel Mountains, and they gained approval to fly drones over certain landslide-prone areas. Those aerial lidar measurements will be helpful in assessing the ongoing risk of debris flows and landslides and also in monitoring for future hazards.

“Emergency managers and the federal agencies are mostly tasked with trying to deal with the immediate situation,” Lamb said. “Whereas something that we can try to help with more as research scientists is to think about real forward-looking measurements.”

Their lidar flights focused on areas of burned mountainside rather than on urban areas. “It’s sad to say, but in some of the areas that were really devastated by the fires, there aren’t homes there [anymore] to be damaged by the debris flows,” Lamb said.

Working with Their Communities

The public messaging that agencies provide is critical for residents to find out about the immediate risks they face, but non-agency scientists also have found ways to engage these communities deeper in the scientific discoveries that are helping them stay safe.

As crews started containing the fires, scientists at the Natural History Museum of Los Angeles County (NHMLA) recognized the need to collect and analyze samples of the ash, not only for the immediate emergency response but also to curate a catalog that scientists could use for longer-term and future studies. Because they have a small staff, the museum’s team solicited community members for ash samples rather than going in to the field themselves.

“They just lost their homes. They want to be treated with respect.”

“We didn’t want to reach out right away, because that would appear as insensitive and not really caring about the people but rather more caring about the science,” said Aaron Celestian, curator of mineral sciences at NHMLA. But once it started raining, they couldn’t wait any longer.

The museum’s community science team approached their existing community partners about collecting ash and found that people were already doing it themselves. The team pivoted, instead showing people how to collect ash without risking personal health or contaminating the samples.

“We didn’t want anybody to do anything that would have any kind of health effects on them long term,” Celestian said. “We had to develop a protocol that could be understood by the community at large, and so that we get the best kind of science out of it in the end.”

Celestian analyzed his first sample on 27 January, measuring the chemical composition of forest ash. He plans to compare the results with those from urban ash.

Natural History Museum of Los Angeles County mineral sciences curator Aaron Celestian prepares one of the collected ash samples for total element analysis to reveal its chemical composition. The whole process takes about 2 hours. Credit: Aaron Celestian/Natural History Museum of Los Angeles County

Then came the question of how to communicate the results. Celestian and the museum’s communications team came up with a two-pronged approach. First and foremost, they consulted with the community member who sent in the ash sample. “They get to decide on how they want their samples to be treated and communicated with everybody else,” Celestian said.

With a resident’s permission, the ash sample was entered into a museum collection for other scientists to check out and analyze. They received 11 samples for the collection.

“Even though I’m collecting the data, it really is their property,” Celestian said. “That’s a big part of making them feel comfortable, making them feel confident in the results.”

“They just lost their homes,” he emphasized. “They want to be treated with respect,” he said, adding that the samples “are really like a family member’s ashes.”

At the same time, Celestian recognized the importance of transparency and that timely information can not only protect people but also help them feel confident in their safety. He began live-streaming his analysis on social media and his blog using anonymized samples.

“People want to know,” Celestian said.

Lamb’s group took a similar approach. They shared their lidar data directly with emergency response managers so they could be incorporated into official responses. They also communicated directly with the public. Lamb had been scheduled to give a public science talk in late January, and he decided to center the science of postfire debris flows.

“I was going to talk about something completely different, and I changed the topic last minute because of this very heightened community interest in understanding what’s happening in the mountains,” Lamb said. Nearly 900 people showed up to listen.

Strong, and Mixed, Emotions

Having a way to help after a disaster—whether through distributing supplies or figuring out whether playground soil has elevated lead levels—can aid community recovery and empower personal healing. In some, it can also evoke a sense of duty.

“I think we have a responsibility to use our skill sets to help the greater Los Angeles area where we live,” Ghosh said. Logically, he knew that sampling water runoff and analyzing it for harmful chemicals is an important part of postfire recovery. But sometimes, it didn’t feel like enough.

“You go up there and you’re collecting water, and people have almost lost their homes,” Ghosh said. “It feels like, ‘Why the hell are you collecting water?’ It may not seem in the moment as important a thing to do. I definitely felt that.”

Studying the risks from these fires “does feel more personal.”

Some residents questioned what the sampling team was doing and whether they were focusing on the right problems. “But we also had neighbors who were like, ‘Thank you so much for doing this, coming out and helping us understand whether we can drink our water, or whether it’s safe to be out,’” Ghosh said. “In fact, some people even let us in to their house, and [we] collected tap water from their house.” Ghosh and his colleagues shared the results of those in-home water tests directly with the homeowners when they got them.

“It’s a lot of mixed emotions,” he added.

Studying the risks from these fires “does feel more personal” for local scientists, Lamb said. “We know people that live in those areas. There’s faculty from Caltech and graduate students that live there, and postdocs and friends. It’s very close to where we live and work. It certainly adds more motivation to try to do anything that we can to help.”

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

Citation: Cartier, K. M. S. (2025), When disaster science strikes close to home, Eos, 106, https://doi.org/10.1029/2025EO250315. Published on 26 August 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

From Devastation to Data

Gale Sinatra and her husband fled their Altadena, Calif., home on 7 January with little more than overnight bags, taking just one of their two cars.

“We thought we were going to be gone overnight,” Sinatra said. “We thought they’d get the fire under control and we’d get back in.”

When the couple did return, weeks later, it was to dig through the rubble of their former home, burned to the ground by the Eaton Fire.

Though they escaped with their lives, health hazards were not behind Sinatra, her husband (who chose not to be named for this story), and others from their neighborhood. The Eaton and nearby Palisades fires filled the Los Angeles Basin with a toxic haze for days, and cleanup efforts threatened to loft charred particles long after the fires were out.

Teams of scientists from across the country, along with community members, monitored air quality in the weeks following the fire, seeking to learn more about respiratory health risks and inform community members about how to protect themselves.

Urban Fires Versus Wildfires

Inhaling smoke from any fire can be harmful. Smoke contains hazardous components, including volatile organic compounds (VOCs), emitted by burning vegetation and products such as paint and cleaning supplies; and particulate matter, such as dust and soot.

About 90% of the particulate matter (PM) in wildfire smoke is PM2.5, or particles smaller than 2.5 micrometers in diameter—small enough to enter the bloodstream and deep areas of the lungs.

These instruments are used by Michael Kleeman to monitor air quality from the back of a car in Victory Park in Altadena, as far north as he can go in the area without entering the evacuation zone. Credit: Michael Kleeman

Urban wildfires present their own dangers, because they burn not just through trees and other vegetation but through homes and infrastructure as well.

When Sinatra returned to her former home, she was struck by everything the fire had burned, from her jewelry to her car. “I just found it very eerie standing in my kitchen, going, ‘Where’s my refrigerator?’” she said. “How do you melt an entire refrigerator?”

In January 2025, the Palisades and Eaton fires ravaged more than 150 square kilometers across cities and wildlands in Los Angeles County. Even as they were personally affected, LA-area scientists worked diligently to understand how fires at the urban-wildland interface create unique hazards via air, land, and water.

In the future, hot and dry conditions enhanced by climate change will continue to raise the risks of fires like these. The work of these scientists can provide a blueprint for rapid hazard assessment, health risk mitigation, and urban planning in other fire-prone communities.

In January 2025, the Palisades and Eaton fires ravaged more than 150 square kilometers across cities and wildlands in Los Angeles County. Even as they were personally affected, LA-area scientists worked diligently to understand how fires at the urban-wildland interface create unique hazards via air, land, and water.

In the future, hot and dry conditions enhanced by climate change will continue to raise the risks of fires like these. The work of these scientists can provide a blueprint for rapid hazard assessment, health risk mitigation, and urban planning in other fire-prone communities.

“From mattresses to carpets to paint to electronics, everything like that burns,” said Roya Bahreini, an environmental scientist at the University of California, Riverside (UCR). Bahreini is also co–principal investigator of the Atmospheric Science and Chemistry Measurement Network (ASCENT), a long-term air quality monitoring project led by the Georgia Institute of Technology, UCR, and the University of California, Davis (UC Davis).

ASCENT, which launched in 2021, has stations across the country, including three in Southern California. During the January fires in Los Angeles, which tore through not only Altadena (an unincorporated inland community) but also neighborhoods along the coast, these stations detected levels of lead, chlorine, and bromine at orders of magnitude higher than usual.

Older houses sometimes have lead paint, asbestos ceilings, or wooden decks and fences treated with preservatives containing arsenic. PVC piping contains chlorine. And flame retardant often contains brominated organic compounds. In these forms, such materials don’t necessarily pose a high risk to human health. But when they are burned and released to the air, they can be dangerous.

Smoke plumes from the Palisades Fire (left) and the Eaton Fire are seen from space on 9 January. Credit: ESA, contains modified Copernicus Sentinel data, CC ­BY-SA 3.0 IGO

Michael Kleeman, a civil and environmental engineer at UC Davis, explained that the short-term mortality associated with high PM2.5 events such as wildfires often comes in the form of a heart attack. But inhaling urban wildfire smoke or the particles kicked up from dust and ash during remediation efforts can present risks that aren’t immediately apparent. “It’s not a heart attack a day or three after the exposure. It’s, like, a cancer risk way down [the road],” Kleeman said. “The long-term exposure [risk] can be insidious.”

Air Quality Maps

Southern California is no stranger to wildfires. (Neither is Sinatra, who has evacuated several times during her 15 years in Altadena.) Frequent droughts in the Los Angeles Basin result in large swaths of parched vegetation. The infamous Santa Ana winds, which blow into the basin from the east and northeast, can cause fires to quickly grow out of control, as was the case in the Palisades and Eaton blazes.

Real-time air quality maps, such as those hosted by the South Coast Air Quality Management District (AQMD) and U.S. EPA, pull from several sources to provide data year-round. More detailed data come from sophisticated instruments set up by the agencies themselves; South Coast AQMD hosts 32 permanent air monitoring stations throughout Los Angeles, Orange, Riverside, and San Bernardino counties.

The Air Quality Management District has permanent installations for monitoring air quality, but in the wake of the January 2025 Los Angeles wildfires, it launched supplemental efforts, gathering real-time air quality data from mobile monitoring vans. Credit: South Coast AQMD

Less detailed but more widespread data on particulate matter come from networks of off-the-shelf air quality measuring tools, such as PurpleAir monitors and Clarity Sensors, that are set up by residents or community organizations.

“It turns out that the areas that the fires were in had [a] really, really dense network of these low-cost sensors,” said Scott Epstein, planning and rules manager at South Coast AQMD. “When you combine that with our regulatory network, we had very good coverage of fine particle pollution.”

This density meant researchers could watch the Eaton and Palisades wildfire plumes as they traveled toward the coast.

An existing AQMD station in Compton, about 23 miles (37 kilometers) south of the Eaton Fire, showed highly elevated levels of toxic metals, including arsenic and lead, between 7 and 11 January as the plume passed over the area. These levels returned to normal within a few days. ASCENT instruments in Pico Rivera, about 14 miles (23 kilometers) south of the Eaton Fire, recorded a 110-fold increase in lead levels from 8 to 11 January.

Permanent air quality measuring stations like these offer one source of public information that residents like Sinatra could consult to make decisions about when to stay indoors or return to a burned area. But when the Palisades and Eaton fires broke out, researchers from AQMD and other institutions set out to supplement these efforts with more granular monitoring.

Mobilizing Quickly Melissa Bumstead (left) and Jeni Knack volunteered to gather air and ash samples in the wake of the Eaton and Palisades fires. Credit: Shelly Magier

In January, researchers from Harvard University; the University of California, Los Angeles (UCLA); the University of Texas at Austin; the University of Southern California (USC); and UC Davis launched the Los Angeles Fire Human Exposure and Long-Term Health Study, or LA Fire HEALTH.

While many Los Angeles residents, including Sinatra, were still under evacuation orders, LA Fire HEALTH researchers were traveling into evacuation zones.

One such researcher was Nicholas Spada, an aerosol scientist who headed down to Los Angeles from UC Davis on 14 January to set up four cascading impactors in Santa Monica (near the Palisades Fire), Pasadena (near the Eaton Fire), Hollywood, and West Hills. These briefcase-sized instruments act like coin-sorting machines, Spada said: They take an air sample, then sort particles into eight different size categories. They take an air sample, then sort particles into eight different size categories, ranging from 10 micrometers (about 1/9 the average width of a human hair) to 90 nanometers (about 1/1,000 the width of a human hair). The instruments collected eight samples every 2 hours until 10 February.

A cascading impactor allows scientists to “associate the particle size profiles with time,” Spada said. The instrument “picks up the changes in the smoke plumes as the fire progresses from active to smoldering to being put out, and then to the mitigation effects.”

The measurements showed that not only were toxic elements such as lead and arsenic present in the air throughout the sampling period but also a high proportion of their mass—about 25%—was in the form of ultrafine particles (on the order of nanometers). Such particles aren’t filtered by N95 masks and can penetrate deep into the body when inhaled, Spada explained.

A team of University of Texas researchers arrived in a van that doubled as a mobile laboratory on 2 February, at which point the fires were out but dust-disturbing remediation efforts had begun. They found that outdoor air quality in the weeks after the fires was back to prefire levels and within EPA guidelines. Indoor samples—especially from homes within the burn zones—showed higher levels of VOCs compared with the outdoor samples.

Neighbors Lend a Hand

Community members got in on the efforts to monitor air quality.

Southern California community members got in on the efforts to monitor air quality, too. Melissa Bumstead and Jeni Knack, codirectors of Parents Against Santa Susana Field Laboratory, worked with researchers to create and distribute flyers about appropriate measures regarding personal protective equipment, as well as a self-sampling protocol for residents who wanted to gather ash samples from their own properties.

About twice a week from 14 January to 19 February, they gathered air and ash samples in Pasadena, Altadena, Santa Monica, Topanga, and Pacific Palisades, then sent them to laboratories, including Spada’s, for testing. Arsenic in all of the ash samples and lead in about a third of them exceeded EPA regional screening levels. Spada noted in communications to residents that these screening levels are based on what’s safe for ingestion by a child and are relatively conservative.

“This is going to help people in the next iteration of fires to know what to do,” Bumstead recalled telling residents in sampling areas.

After the Ashes Sinatra lost her Altadena home in the January 2025 Eaton Fire. When she returned to dig through the rubble, she drove past “chimney after chimney after chimney with no house attached.” Credit: Gale Sinatra

The next fire, Sinatra said, is something that weighs on her as she and her neighbors consider the prospect of rebuilding.

When rain finally arrived in Southern California on 26 January, it helped extinguish the fires and tame the dust disturbed by remediation efforts, reducing the risk that people would inhale toxins.

Still, those toxins were also present in the soil and water. When Sinatra and her husband returned to the charred site of their home, they took every precaution they’d heard about from the news, the EPA, community leaders, and neighbors: They wore respirators, hazmat suits, goggles, and two pairs of gloves each to protect themselves.

Concerns about potential long-term consequences of the air they had already breathed, as well as the soil beneath them, linger as they wait for more data.

“Everyone feels there’s a significant chance of a future fire,” Sinatra said. We’re “wondering about whether it would be safe to live up there, [in] regards to the soil quality and the air quality, and whether it’s going to happen again.”

—Emily Dieckman (@emfurd.bsky.social), Associate Editor

Citation: Dieckman, E. (2025), Where there’s fire, there’s smoke, Eos, 106, https://doi.org/10.1029/2025EO250308. Published on 26 August 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

From Devastation to Data

The 2025 Palisades and Eaton Fires torched scrub-lined slopes of the San Gabriel and Santa Monica Mountains, as well as buildings, streets, cars, and infrastructure.

Before the flames were even contained, scientists from throughout the Los Angeles (LA) metro area turned to the skies, their labs, and their communities to study the extent of the damage. Their work is informing residents and other researchers about how hazards from the fires have shifted in the weeks and months after containment, and how they could change in the years to come.

Scientists are learning how the fires, which burned along the urban-wildland interface, were distinct from strictly urban or rural fires in terms of chemistry, topographic changes, and follow-on hazards.

During Containment

While firefighters were still battling flames on the ground, an airborne surveyor team took stock of the damage, mapping the scope and extent of the fires and assessing which areas needed immediate remediation.

On 11 January 2025, NASA’s Airborne Visible/Infrared Imaging Spectrometer 3 (AVIRIS-3) flew over Los Angeles County mounted on a B200 research plane. The instrument provided some of the first aerial data assessing the scope of the Palisades Fire while it was still smoldering. It flew over the Eaton Fire soon thereafter.

“We immediately looked for methane or natural gas,” said Robert Green, principal investigator for AVIRIS-3 at NASA’s Jet Propulsion Laboratory in Pasadena. Natural gas leaks can pose health and safety risks to first responders. The instrument did not detect any abnormalities.

“But then we realized we had this dataset and could do advanced spectroscopic mapping of the burn severity and the burn products—the char and the ash,” Green said.

One of AVIRIS-3’s quick-turnaround data products is this aerial map of the fraction of burn material, char, and ash within the spectrum of each pixel. Values from 0 (no burn, dark) to 1 (entirely burned, red) describe the burn fraction of the exposed surfaces. Nearly all structures have moderate to severe surface burning (yellow), and few pockets of vegetation (green) survive. Credit: AVIRIS-3/NASA/JPL, via Rob Green

AVIRIS-3 data showed that the Eaton Fire burned more wildland area than urban area, largely because fire managers focused prevention efforts on areas in which people were endangered, Green explained. Initial maps of burn severity, which were provided to first responders, showed that within the burn area, nearly all structures suffered moderate to severe surface-level burns. Very few patches of urban vegetation survived.

“We’ve never had an urban fire like this to collect datasets.”

The instrument completed subsequent surveys of the Eaton and Palisades burn scars in late May.

“We’ve never had an urban fire like this to collect datasets,” Green said. “There’s a whole bunch of new spectroscopic compounds established by burning these [urban] materials, which are different than those you would find in a natural environment.” These surveys will help scientists track combustion products and how long they persist in the soil.

Lead Laden

After the fires were contained, many local scientists mobilized with the tools and people they had at hand—themselves, their students, and even their children—to collect ash, dust, and soil samples. They and fellow residents wanted to know what chemicals enter the environment when wildland-urban fires burn, how bioavailable they are, and how long they present a danger.

“We were scrambling to get ready for the rain. A lot of these data, from a scientific point of view, are perishable.”

Many scientists homed in on lead contamination. Of the more than 7,000 homes and structures that burned, most were built before 1975, when lead-based paint was commonly used. Lead that enters the body is easily absorbed into blood and can cause significant neurological harm, especially in children. It is particularly dangerous when inhaled or ingested as fine dust, and fire ash and dust are key exposure routes. Residents wondered when it would be safe for children and pets to play outside and whether it was safe to eat vegetables from their gardens.

Time was of the essence to collect samples, explained Joshua West of the University of Southern California (USC) in LA, not only because of the potential health impact but also because imminent wind and rain threatened to redistribute or wash away the fires’ by-products.

“We were scrambling to get ready for the rain,” West said. “A lot of these data, from a scientific point of view, are perishable.”

USC researcher Seth John used a handheld X-ray fluorescence machine to test the lead concentration in roadside dust near the Eaton Fire burn scar in early February. Credit: Cecilia John

A team of USC scientists, including West and Earth scientist Seth John, tested dust and ash along the edges of the Altadena burn scar in late January. Over several weekends, the scientists used handheld instruments to measure the lead concentrations in dust that had accumulated on streets and playgrounds. They also collected samples for further analysis in the lab.

EPA’s thresholds for levels of lead in residential soil and playgrounds are 200 parts per million generally and 100 parts per million for sites with multiple sources of exposure. The researchers found that a few roadside spots exceeded those thresholds but no playground samples did.

The team also found a strong correlation between lead levels and proximity to burned structures but not to wildland.

“It seems very clear that there is higher lead in the areas with destroyed structures,” John said.

Wildland ash had low concentrations of lead.

A team from the California Institute of Technology (Caltech) in Pasadena similarly found that ash closest to burned structures contained higher concentrations of lead. The Caltech analysis could differentiate wildland and urban ash and found that wildland ash had low concentrations of lead.

Researchers at the University of Southern California tested lead concentrations in dust samples from streets (circles) and playgrounds (triangles) along the Eaton Fire burn scar. They found higher concentrations of lead (darker blue) in dust near burned and damaged structures (black dots). Credit: map: Seth John, Josh West, and Sam Silva; data collection: Mia Bradshaw, Katherine Thomas, and Cecilia John

“No amount of lead is safe,” John cautioned. “That said, these levels are elevated, but I wouldn’t say they’re elevated to extremely toxic levels.” The researchers found similar trends in dust near the Palisades burn scar.

The USC team returned to the same locations every few weeks to collect more roadside dust samples. As of June, lead concentrations were slowly going down but were still elevated in most of the sample locations in Altadena, John said.

Another Caltech team measured lead concentrations in dust—a fine mix of ash particles, soot, and aerosols—that accumulated on indoor and outdoor surfaces. Many dust samples had lead concentrations exceeding EPA limits. Although simple cleaning with water was often enough to remove that lead, cleanup efforts can disturb new dust and prolong exposure risk.

A survey of garden soil samples found that about 35% had lead concentrations exceeding California’s recommended lead limit, but only about 7% exceeded the EPA’s limit (which is higher). They also found that soil lead levels could vary significantly within a single residential yard and that finer soil particles (smaller than 250 micrometers) had higher lead levels than a mixed soil sample.

The Risks of Rain

As cleanup efforts began in earnest and residents started returning, they were aware of the lingering hazard of debris flows and landslides from the charred slopes of the San Gabriel and Santa Monica Mountains.

The mountains are steep, and gravity slowly moves soil, rocks, and sand downhill, explained Emily Geyman, a graduate student researching climate and surface processes at Caltech. Low brush and scrappy mountainside shrubs typically interrupt that flow and accumulate that debris before it reaches foothill neighborhoods.

“Once you incinerate that [vegetation], those sand grains that are perched at this angle that should be unstable come cascading down,” Geyman said.

What’s more, fires can mobilize contaminants and change soil chemistry so that it repels, rather than absorbs, water and loosens soil so it’s more likely to fall downslope, explained West, who also studied the potential for debris flows in the San Gabriels. Gravity funnels sand and debris into natural channels where it builds up, compounding runoff and erosion risks.

“These are probably some of the first fires in which we have the post-fire, pre-rain topography at really high resolution.”

Studies of past wildfires in the San Gabriels have shown that between 20 and 50 years’ worth of soil erosion happens during the first 2 years following a wildfire. Sudden erosion can damage infrastructure, fill debris basins, and strip ecosystems of critical soil nutrients and structure.

Between 25 January and 24 March, Geyman and other Caltech researchers conducted 10 uncrewed aerial vehicle (UAV) lidar surveys above the Eaton Fire burn scar. They surveyed mountain catchments and debris basins—artificially dug repositories to contain flows—before and after every major rain since the fires.

“These are probably some of the first fires in which we have the post-fire, pre-rain topography at really high resolution,” West said. “Being able to capture that time sequence going forward is one of our big goals.”

A significant rainfall on 13 February triggered debris flows in almost every mountain catchment in the Eaton Fire burn area, Geyman said. Using pre-rain and post-rain lidar scans, the researchers estimated that 680,000 cubic meters of material cascaded downhill, “equivalent in volume to about 270 Olympic-sized swimming pools,” Geyman added.

Debris basins captured most of the flow before it affected residential neighborhoods. “The debris basin infrastructure largely did its job,” Geyman said. Debris flows have not caused any additional loss of life.

Similar UAV lidar work by geomorphologist Seulgi Moon and her colleagues at the University of California, Los Angeles (UCLA), resulted in digital elevation maps of debris channels in Topanga Canyon, an area in the Santa Monica Mountains affected by the Palisades Fire, before and after the February rains. They continue to assess debris flow hazards in the canyon.

On 19 February, a debris flow in Topanga Canyon blocks roads west of the Palisades burn area. Credit: Seulgi Moon The Paths Ahead

UAV surveys continue, and scientists are monitoring debris channels to assess the ongoing risk of landslides and debris flows.

“We plan to continue the surveys before and after each major rain event [through] winter 2026 or until…the loose sediment released from the hillslopes during the fire is cleared out,” Geyman said.

Moon and her colleagues plan to install a geophone and five debris flow monitoring stations in the canyon to monitor ongoing hazards in the area for 2 years. Any ground motion, whether from a skittering animal or an imminent debris flow, will create vibrations. A geophone converts them into a measurable voltage.

“We want to make the connection between how much rain is coming and how much sediment will come downstream,” she said.

Data from both groups will help scientists understand which debris flow mechanisms are most likely, track the volume of material at which flows become imminent, and help inform hazard maps to aid emergency response.

After the initial rush of dust, ash, and soil collection, many research groups shifted to community-led sampling efforts. John and West, for example, set up a free community sampling program for lead in soils and received more than 1,000 samples by mid-May. Some groups are reaching out to residents who want their soil tested or who want to contribute to scientific efforts. Other teams at UCLA and Loyola Marymount University created similar lead soil testing programs for communities.

The AVIRIS-3 team is working with laboratory scientists to match the aerial spectral signatures to those of burn products in ash samples. Green said that every burn compound the team catalogs will help efforts to protect first responders during future urban fires and inform future instruments that could identify when burnable material builds up in fire-prone areas.

Additional flyovers may happen when AVIRIS-3 flies to or from its home base in LA, Green said. Those data could be used to track how environmental damage such as toxic ash contamination and soil erosion change over time.

“That might inform our understanding [of] how this urban-rural interface is changing and what the recovery looks like,” Green said.

—Kimberly M. S. Cartier (@astrokimcartier.bsky.social), Staff Writer

Citation: Cartier, K. M. S. (2025), Burning urban and wild land alike, Eos, 106, https://doi.org/10.1029/2025EO250309. Published on 26 August 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

From Devastation to Data

As multiple fires raged through Los Angeles in January 2025, Bernadeth Tolentino had one more thing to worry about: kelp.

Tolentino, a marine biologist and graduate student at the University of Southern California, is part of a lab that runs a gene bank of kelp spores. The repository preserves genetic diversity and allows scientists to bolster struggling populations.

As the roaring fires turned homes, cars, and businesses into chemical-laden ash, Tolentino realized that runoff from postfire rains would eventually carry that ash to the sea.

In the ocean, the ash threatened to block sunlight and pollute the water surrounding one particular kelp population in Santa Monica Bay—a population not represented in the gene bank. She needed to reach the kelp before runoff damaged viable spores.

The dive team, including Tolentino, scrambled to apply for permits, gather their equipment, and coordinate dives before rainstorms carried too much toxic runoff to the site. “It was a little bit of a rush job,” she said. Accelerated permitting from the California Department of Fish and Wildlife allowed the team to reach the kelp population just in time.

They dove four times, collecting spores from southern sea palm, feather boa, and golden kombu kelp, which may be used to restore regional ecosystems in the future.

AltaSeeds Conservancy curator Michael Marty-Rivera places kelp spores into biobank storage. Credit: Taylor Griffith

Tolentino was one of many water quality and marine scientists who collected valuable, time-sensitive information after the LA fires. “It felt great to be able to apply what I know to jump on this really urgent matter,” she said.

Ash in the Water

On 8 January, a day after the Eaton Fire began, scientists from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) were about 80 kilometers (50 miles) away on a routine monitoring cruise. CalCOFI has been monitoring the state’s coastal waters for more than 75 years, collecting oceanographic and ecological data.

But as the fires raged, scientists on the deck of the CalCOFI vessel—and their colleagues on land—recognized the unique opportunity posed by the disastrous event. Here was a chance to collect real-time data on the environmental impacts of an urban fire without needing to plan and launch a separate expedition. They pivoted, used a planned crew exchange to gather more equipment, and increased their sampling.

Even kilometers off the Pacific coast, those on board a CalCOFI (California Cooperative Oceanic Fisheries Investigations) monitoring cruise observed ash in the air on 9 January. Credit: Rasmus Swalethorp/Scripps Institution of Oceanography, University of California, San Diego

The event provided “a perfect opportunity to study the ocean impact of this very devastating urban fire,” said Julie Dinasquet, a marine microbiologist at the Scripps Institution of Oceanography, University of California, San Diego, who works closely with the CalCOFI team. Dinasquet was not on board the monitoring cruise but helped to coordinate the work during the fires.

Those on board were shocked at the effect the fires were having on the ocean, Dinasquet said. She and her colleagues had to wear masks and goggles when the smoke became too potent.

On board the CalCOFI cruise on 9 January, researchers from NOAA Fisheries’ Southwest Fisheries Science Center hold up a plankton net full of ash and debris collected from the ocean surface. Credit: Rasmus Swalethorp/Scripps Institution of Oceanography, University of California, San Diego

Some particles that landed on the water were big enough to see with the naked eye. The largest chunks the group measured were 5 centimeters wide—quite unusual given how far from the fires the samples were taken, said Douglas Hamilton, an Earth systems scientist at North Carolina State University who collaborates with the CalCOFI team.

Closer to shore, the onboard team pulled up a plankton net that was full of black ash. And water samples, typically filled with plankton, were filled instead with soot and debris.

Hamilton thinks that particles traveling from the primarily urban fires to the ocean contained more toxic material than those from blazes burning primarily biological fuels (such as brush).

Scientists know that falling ash and runoff from wildfires that burn mostly vegetation add nutrients to the ocean, sometimes spurring primary production and altering ocean biogeochemistry. The samples from the CalCOFI cruise will shed light on how urban fires can also affect ocean biogeochemistry—a rather new field, Hamilton said.

“This is really the first time this has been able to be observed.”

Ash from urban fires contains very different chemicals than ash from burned areas of less developed land, and therefore might have very different effects on the ocean. “We’re adding this extra layer of complexity,” Hamilton said. “How does this urban wildfire change the narrative of the way that we’ve been thinking about how wildfires might be impacting ocean ecosystems? This is really the first time this has been able to be observed.”

In April, a very large bloom of the toxic phytoplankton Pseudo-nitzschia unfolded along the California coast, killing sea lions and dolphins. Though the event is not unusual under La Niña conditions, scientists are questioning whether material that entered the ocean from the fires may have contributed to the bloom.

Dinasquet plans to analyze the composition of the ash and water samples collected on board the CalCOFI cruise and compare them with ash transported from fires in less developed areas. Hamilton will create models that could be used to project how future urban fires may affect the ocean.

The January fires were the first large coastal urban fires to have affected the ocean at such a scale. “This is an absolutely tragic event, but it’s the first of its kind,” Hamilton said. “So we need to learn from that.”

Rushing for Runoff

Fires’ effects on marine ecosystems don’t come from just the air: As rainwater percolates through burned neighborhoods, runoff carries pollutants through the watershed and into the ocean, too.

When rainstorms hit after the fires, Adit Ghosh was ready. More rainfall meant more runoff and a chance to collect samples that might shed light on how toxic metals such as lead, arsenic, iron, and vanadium, as well as organic pollutants, move through the watershed.

Rain events after the January Los Angeles wildfires caused debris flows, like this one in Mandeville Canyon on 13 February, 2025.Credit: Rain Blankenship

Ghosh, a geobiologist at the University of Southern California, and his colleagues monitored the forecast in the weeks after the fires. No matter the hour, when they expected rain, they headed out to four field sites to collect runoff.

The team especially wanted to sample runoff from the first storms to hit the area after the fires,as that water, they hypothesized, would contain the highest amounts of pollutants. During the first storm, which occurred in late January, the team stayed out until nearly midnight, filling bottles and vials with runoff. Since then, Ghosh has ventured out into rainstorms more than 2 dozen times, trying to capture runoff each time there’s enough flow to sample.

At one point during the sampling, a University of California, Los Angeles professor led the research team around a burned neighborhood in Mandeville Canyon. Ghosh did a double take at the remains of one of the houses—he’d seen it burn down, live, on television.

“You see it on TV, but when you walk up to it, you see the devastation,” he said. “It really hit home. It was really sad.”

Ghosh said he feels that as a member of the Los Angeles community, he has a responsibility to use his skill set to help area residents understand how the fires may be affecting their water.

“It’s important that we do this work, that we try to find these things out quickly and let the public know what we found.”

“It’s important that we do this work, that we try to find these things out quickly and let the public know what we found.”

As this article was written, the team had not finished analyzing all of the samples, but preliminary results show that lead and arsenic are elevated in runoff from burned urban areas, though not above EPA limits. Lead and arsenic may have been elevated in the area already, as they are regularly derived from several natural and urban sources.

Ghosh and his team want to collect streamflow samples from the unburned watersheds during next year’s winter storms to see how the contamination they’ve found compares with background levels.

Ghosh hopes that a full analysis of the data will help scientists and the public understand how chemicals in runoff differ between burned and unburned, and urban and less developed, areas. Ghosh and his collaborators also plan to create time series analyses for each of the pollutants they sampled to show how concentrations of pollutants in runoff change over time after a fire and over the course of multiple rainstorms.

“If there’s another fire somewhere, we can have a better understanding of how those [water quality] risks are going to linger after the event,” he said.

Spotting Plumes from Above

One public agency is helping coordinate much of the aquatic research. After the fires, the Southern California Coastal Water Research Project started to keep track of what samples scientists were collecting to reduce redundancies and help everyone involved know what data are available.

“We’re going to learn some great things from this.”

“We’re going to learn some great things from this,” said Michelle Gierach, an oceanographer at NASA’s Jet Propulsion Laboratory (JPL) working on ocean monitoring projects.

Gierach has been struck by that high level of collaboration in the postfire research. As just one example, she’s been in conversation with the CalCOFI team to determine whether their samples of ash-laden water can help her team at JPL validate satellite observations and derive new algorithms to assess the impact of future urban fires on the ocean. Her team at JPL is also working with colleagues at the University of California, Los Angeles and the University of California, Merced to assess the impacts of the fires on aquatic ecosystems.

“If our data can support the efforts of state agencies, municipalities, NGOs [nongovernmental organizations], academic groups, and others conducting fieldwork and analyses, and ultimately enhance understanding of urban wildfire impacts on nearshore and coastal aquatic environments, then sharing [them] is not only valuable—it’s essential,” Gierach wrote in an email.

She finds a “glimmer of hope” in seeing the scientific community rallying together so rapidly and coordinating so well. “It’s inspiring that in the face of this horror, something positive can happen.”

—Grace van Deelen (@gvd.bsky.social), Staff Writer

Kimberly M. S. Cartier also contributed to this reporting.

Citation: van Deelen, G. (2025), Scrambling to study smoke on the water, Eos, 106, https://doi.org/10.1029/2025EO250310. Published on 26 August 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Solid Earth

Seismic monitoring has served as one of the most common and reliable tools for volcanic eruption forecasting. While seismic networks have many advantages over other types of monitoring, the data can be complex to interpret because they include signals from a large variety of sources.

Carleo et al. [2025] analyze 84 eruptions from the South-East Crater of Mount Etna between 2012 and 2023 using data from a 200-meter-deep borehole strain meter. To complement the low frequency strain signals associated with the eruptions, the authors produce a strain tremor record from the higher frequency strain data that is consistent with signals from a nearby seismometer. This large dataset permits analysis using an automated clustering approach.

Interestingly, classification of the strain data comes much closer to matching those made by volcanologists based on the eruption behavior, than does the tremor-based classification. So, while tremor may reflect both deep and shallow magmatic fluid processes, which can be complex and time varying, the strain data may better capture the amount of magma flowing out of the reservoir. This implies that broader implementation of real-time strain monitoring could provide important information for eruption early warning.

Citation: Carleo, L., Currenti, G., Bonaccorso, A., & Sicali, A. (2025). Relation between volcanic tremor and geodetic strain signals during basaltic explosive eruptions at Etna. Journal of Geophysical Research: Solid Earth, 130, e2025JB031564. https://doi.org/10.1029/2025JB031564

—Gregory P. Waite, Associate Editor, JGR: Solid Earth

Text © 2025. The authors. CC BY-NC-ND 3.0
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In May 2025, I recorded 66 fatal landslides worldwide, resulting in 313 fatalities. The number of fatal landslides is significantly above the long term mean.

Somewhat later than planned, resulting from other workload challenges, this is my latest update on fatal landslides in 2025, covering the month of May. I hope to be able to post data for June in the next few days.

As always, allow me to remind you that this is a dataset on landslides that cause loss of life, following the methodology of Froude and Petley (2018). At this point, the monthly data is provisional.

In May 2025, I recorded 66 fatal landslides worldwide, resulting in 313 fatalities. This is very significantly above the 2004-2016 average number of landslides (n=28.3) and slightly above the average number of fatalities (n=308.8).

This is the histogram by month for the number of fatal landslides in 2025 through to the end of May:-

The number of fatal landslides to the end of May 2025 by month.

The figure, with the higher monthly total in May than for the previous months, primarily reflects the increases in rainfall that start to occur in many Northern Hemisphere areas in May, most notably pre-monsoonal precipitation in large parts of Asia. As such, the trend is quite typical.

This is the graph of the cumulative total number of landslides, organised by pentads. This goes to pentad 30, which ends on 30 May:-

The number of fatal landslides to 30 May 2025, displayed in pentads. For comparison, the long term mean (2004 to 2016) and the exceptional year of 2024 are also shown.

As the above graph shows, at the end of May, 2025 was trending very much above the long term average, and it was remarkably similar to the exceptional year of 2024. This is quite surprising, but may reflect continued high atmospheric temperatures. The EU Copernicus atmospheric temperature note says the following:

“May 2025 was the second-warmest May globally, with an average ERA5 surface air temperature of 15.79°C, 0.53°C above the 1991-2020 average for May.“

As a teaser for the June data, this trend of exceptional landslide occurrence did not continue into the following month.

Reference

Froude M.J. and Petley D.N. 2018. Global fatal landslide occurrence from 2004 to 2016. Natural Hazards and Earth System Science 18, 2161-2181. https://doi.org/10.5194/nhess-18-2161-2018

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
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body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

Advocates, scientists, doctors, members of Congress, kids, parents, and other individuals spoke out in a series of hearings last week to let the Environmental Protection Agency know how they feel about a potential sea change in climate and environmental policy: the proposed repeal of the 2009 Endangerment Finding. 

 
Related

•  Submit Your Own Public Comment
•  EPA Releases Proposal to Rescind Endangerment Finding
•  Public Commenters Overwhelmingly Oppose EPA’s Plan to Curtail Key Climate Protections (Mother Jones)
•  What’s Changed—and What Hasn’t—Since the EPA’s Endangerment Finding
•  Get Involved: AGU Science Policy Action Center
 

In 2009, the EPA found that current and projected concentrations of greenhouse gases threatened the public health and welfare of current and future generations. The finding is the legal underpinning for many EPA greenhouse gas regulations. The EPA announced a proposal to rescind the finding on 29 July at an auto dealership in Indiana. If finalized, the proposed rule would repeal “all greenhouse gas emissions regulations for motor vehicles,” according to the EPA.

Day 1 of public hearings, 19 August, opened with remarks from Aaron Szabo, assistant administrator in the Office of Air and Radiation. Szabo indicated the EPA’s proposal to reconsider the Endangerment Finding was aligned with President Trump’s commitment to “unleash American energy, lower costs for Americans, [and] revitalize the American auto industry.”

The proposal was open for public comment from 19-22 August, and remains open for written submissions.

The following nearly 12 hours of testimonies included a series of comments from state attorneys general, pleas from parents and children concerned about respiratory health, and physicians arguing that the Endangerment Finding protects their patients. 

Leslie Glustrom, a biochemist from Colorado, is speaking with a hoarse voice. Wildfire smoke in the state “makes it very difficult for me to speak, so hopefully you will take that as part of the evidence in this record,” she said.

— Eos (@eos.org) 2025-08-19T13:08:58.771Z

The vast majority of speakers asked the EPA not to revoke the Endangerment Finding, and many said the proposal to do so countered EPA’s mission to protect human health and the environment.

@agu.org's own Elizabeth Landau is next up. “I am testifying on behalf of AGU and its scientists, who affirm that climate change, which is unequivocally driven by human activities that increase greenhouse gas emissions, is endangering human health and welfare in the US and globally,” she said.

— Eos (@eos.org) 2025-08-19T18:39:10.743Z

The next day, hearings resumed after additional comments from Szabo and the EPA’s Bill Charmley, director of the agency’s Assessment and Standards Division. Charmley said even after the hearings, anyone could still send the EPA written comments, and that the EPA would provide a written response to the testimonies in the near future.

Representatives from multiple religious organizations provided testimonies against the EPA proposal, arguing that members of certain faiths have a religious responsibility to protect the environment and keep children and vulnerable people safe from the health harms that climate change brings. 

Victoria Goebel, also EEN, says that the Bible calls us to ask justly, and that we cannot do that while ignoring the unequal impacts of climate change.Heat waves cause >12,000 deaths every year & that number will only grow. She says the proposal is a threat to life & calls this a pro-life issue.

— Eos (@eos.org) 2025-08-20T14:54:53.134Z

Melanie Aron, co-chair of the Jewish Earth Alliance, said her mother, uncle, and many members of her congregation have asthma."Air quality is key to their survival," she said. "I believe it is our duty to preserve God's creation and to act as stewards, passing that gift on to future generations."

— Eos (@eos.org) 2025-08-21T14:16:55.804Z

Days 3 and 4 included hour upon hour of additional testimonies, still almost entirely against the proposal. 

Clean air advocacy groups, such as Moms Clean Air Force, had a strong showing at the hearings. Many parents affiliated with such groups recounted stories of watching their children suffer from asthma attacks, heat-related health problems, and the stress of growing up in a quickly changing world. 

Stephanie Hernandez from D.C. laments that she couldn't let her daughter play outside this summer due extreme heat & last summer due to smokey skies. "Climate change has influenced our family planning," saying she and her husband don't know if they want to have another child in a worsening climate.

— Eos (@eos.org) 2025-08-21T12:24:12.532Z

Charlie Inglis, age 13, said the repeal would mean "moving backwards" as a country."I speak for my generation when I say that the world we will inherit will be in shambles if we permit actions such as this," he said. "Climate change isn’t some far-off future problem. It’s happening right now."

— Eos (@eos.org) 2025-08-22T15:19:15.701Z

By our count, at the end of the four full days of public hearing testimony, we’d heard hundreds of Americans speak out against the EPA proposal and fewer than 20 speak in favor. Those in favor of rescinding the Endangerment Finding included representatives from the American Petroleum Institute, the CO2 Coalition, and auto industry trade groups, as well as Kathleen Sgamma, an oil and gas advocate who was under consideration to lead the U.S. Bureau of Land Management but withdrew.

—Grace van Deelen (@gvd.bsky.social), Staff Writer

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2025. AGU. CC BY-NC-ND 3.0
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Plants use nitrogen to produce proteins, enzymes, and chlorophyll: all necessary components to perform photosynthesis, in which plants remove carbon from the atmosphere and store it in their leaves, roots, and soil.

However, though the atmosphere is made up of more than 78% nitrogen, the element is unusable for plants in its natural form. Tiny microorganisms called diazotrophs are responsible for “fixing” nitrogen into a form that plants can absorb and use. Diazotrophs live in the soil and in living and decaying plants, creating important partnerships with both naturally growing vegetation and agricultural crops.

Because plants need the nitrogen to grow and remove carbon from the atmosphere, understanding the global distribution of biological nitrogen fixation (BNF) is crucial for building accurate climate models.

But a new study makes a surprising update to global BNF estimates: Forests, grasslands, and other natural areas may have access to between a quarter and two thirds less biologically fixed nitrogen than previously thought. In previous studies, most field measurements of BNF in natural settings were taken from locations such as tropical forests, where nitrogen-fixing organisms are 17 times more abundant than the global average, creating an overestimation of nitrogen availability. This new work, coauthored by a team of 24 international scientists, examines a broader range of ecosystem types and provides a more detailed picture of the global distribution of nitrogen fixation.

Modernized Mapping

A group of researchers, many of whom are involved in the new study, first published a paper on how to model BNF in 1999, explained lead author Carla Reis Ely, an ecosystem ecologist at the Oak Ridge Institute for Science and Education. “But they knew that there were some issues, particularly with data on the abundance of nitrogen fixers, that needed to be addressed.”

The scientists involved with the updated project started by reviewing a compilation of field measurements and distribution data on BNF across natural ecosystems. They found that the sampling bias in past research had produced an overestimation of global nitrogen availability.

Reis Ely said that “it makes sense” that scientists hoping to measure BNF would do their research in places where they know BNF is occurring. “It’s very hard to propose a project where scientists were going to go to a place to measure nitrogen fixation where they know nitrogen fixation is not happening.”

They compiled more than 1,100 existing measurements of BNF rates from natural field sites, ranging from tropical forests to the Arctic. In doing so, they aimed to build a much larger and more representative dataset on how common nitrogen-fixing organisms and their hosts (such as shrubs and mosses) are across various regions and ecosystems. Once they had gathered and organized the measurements of BNF rates from specific sites, they upscaled those rates to estimate and map global nitrogen fixation rates for each of Earth’s biomes.

From Forests to Farms—and Beyond

According to the study’s findings, the amount of nitrogen fixation by microbes in natural environments is approximately 25 million tons lower than previously estimated.

According to the study’s findings, the amount of nitrogen fixation by microbes in natural environments is approximately 25 million tons lower than previously estimated—the equivalent of 113 fully loaded cargo ships. Most of it occurs in tropical forests and drylands, but Reis Ely noted that soils, biocrusts, mosses, and lichens also conduct high amounts of nitrogen fixation.

Though naturally occurring nitrogen fixation is lower than previous estimates, agriculturally based nitrogen fixation has actually been underestimated, the researchers discovered after sorting through thousands of measurements of agricultural BNF. When natural and agricultural datasets were combined, “we found both lower natural nitrogen fixation and higher agricultural nitrogen fixation than prior estimates, [indicating] an increasing human signal on this essential process worldwide,” said Steven Perakis, an ecologist with the U.S. Geological Survey at the Forest and Rangeland Ecosystem Science Center and one of the study’s authors.

Crops like soybeans and alfalfa host bacteria that are fixing much more nitrogen than the natural systems that they replaced were fixing. Even though agricultural nitrogen-fixing crops cover only 6% of Earth’s land, they have boosted global nitrogen fixation by 64% since preindustrial levels.

This increase comes with pros and cons: Nitrogen-fixing crops can help feed Earth’s growing population, and they tend to be more eco-friendly than crops requiring chemical fertilizers. But too much nitrogen can upset the nutrient balance in soils and threaten biodiversity by feeding the growth of invasive plants. Further, excess nitrogen can be converted into the greenhouse gas nitrous oxide, and runoff from these soils can leach into groundwater and cause algal blooms.

“It’s a Goldilocks sort of thing. You want just enough, but not too much, for healthy functioning of ecosystems.”

“Less nitrogen fixation in natural areas could mean reduced capacity [for plants] to uptake carbon from the atmosphere and help mitigate climate change,” Reis Ely said. “On the other hand, if we underestimate how much agricultural nitrogen fixation is happening, we are also underestimating how much excess nitrogen we are adding to natural environments.”

Understanding this balance has implications for estimating nitrogen needs in agriculture as well as how forests grow and store carbon as carbon dioxide levels rise. “It’s a Goldilocks sort of thing. You want just enough, but not too much, for healthy functioning of ecosystems,” said Eric Davidson, a biogeochemist at the University of Maryland Center for Environmental Science who was not involved in the study.

With this new dataset, researchers can now update their models, which may have been under- or overestimating the nitrogen fixation occurring in natural and agricultural settings. Correct estimates can factor into plans for mitigating climate change. “Could these numbers, these global estimates, change in the future?” Davidson said. “Yes, they could with better understanding. But for the time being, it would appear that this is a significant improvement.”

—Rebecca Owen, Science Writer (@beccapox.bsky.social)

Citation: Owen, R. (2025), Nitrogen needs could be limiting nature’s carbon capacity, Eos, 106, https://doi.org/10.1029/2025EO250312. Published on 25 August 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
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Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Advances in Modeling Earth Systems

What determines whether a cloud produces rain? This question has been challenging atmospheric scientists for decades due to difficulties in validation with real-world observations alone.

Chen et al. [2025] used the Pi Cloud Chamber at Michigan Technological University to provide steady, repeatable laboratory measurements for a range of aerosol injection rates. The scientists tested high-resolution numerical models of varying complexity, from a one-dimensional turbulence model to 3D large-eddy-simulations. Each model simulated how rapidly injected aerosols activate into droplets, grow, and fall out within the turbulent, moist chamber.

All models exhibited similar trends in droplet number concentration and mean droplet size in response to variations in the aerosol injection rates, but the exact values for a given injection rate differed greatly. These differences arose from how models represented processes such as droplet formation, particle loss through chamber’s bottom and sidewalls, near-wall moisture exchange, and turbulence properties. Despite these disparities, the models agreed on key scaling relationships between aerosol injection rates and droplet properties, consistent with both chamber measurements and theory.

The results highlight the unique value of laboratory facilities for benchmarking and improving cloud microphysics in models and point to priorities for future work to better constrain models and reduce uncertainty. More broadly, this first-of-its-kind model intercomparison demonstrates how laboratory measurements can inform and improve model representation of cloud-aerosol interactions.

Citation: Chen, S., Krueger, S. K., Dziekan, P., Enokido, K., MacMillan, T., Richter, D., et al. (2025). A model intercomparison study of aerosol-cloud-turbulence interactions in a cloud chamber: 1. Model results. Journal of Advances in Modeling Earth Systems, 17, e2024MS004562. https://doi.org/10.1029/2024MS004562

—Jiwen Fan, Editor, JAMES

Text © 2025. The authors. CC BY-NC-ND 3.0
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Source: Global Biogeochemical Cycles

Throughout the first half of 2020, average monthly temperatures in Siberia reached 6°C above the norm. The situation climaxed on 20 June, when the temperature in the town of Verkhoyansk climbed to 38°C (100.4°F), the highest temperature ever recorded north of the Arctic Circle. With the extreme heat came wildfires, insect outbreaks, and thawing permafrost.

Now Kwon et al. suggest that the effects of the 2020 heat wave were still detectable the following year in the form of warmer- and wetter-than-usual soils.

The researchers obtained data on temperatures, precipitation, and other climatic factors from the European Centre for Medium-Range Weather Forecasts and incorporated them into a model of high-latitude ecosystems. To capture the effect of the 2020 Siberian heat wave, they replaced data from 2020 with data from each of the previous 5 years (2015 to 2019), which provided five estimates of what regional ecosystems might have looked like in 2021 had the heat wave not occurred.

The analysis indicated that the high heat caused soil temperature to remain roughly 1.2°C, or about 150%, warmer in 2021 than it would have been without the heat wave, even though air temperatures had returned to normal. The warmer temperatures also melted soil ice, resulting in wetter soil than usual. Root zone soil water availability, a measure of how much water soil can hold in the rooting depth of plants, increased by 10.9% in forests in 2021 and by 9.3% in grasslands. However, some of this meltwater left the soil via runoff.

In response to warmer, wetter soil, microbes proliferated and caused the soil ecosystem to emit more carbon dioxide than usual, the modeling indicated. In forests, this effect was largely offset by an increase in photosynthesis as plants flourished under the new conditions. In grasslands, on the other hand, photosynthesis initially increased during the heat wave event but then quickly decreased until 2021 as plants used up the available water and died off. As a result of the 2020 heat wave, the researchers reported, forests gained an additional 6 grams of carbon per square meter in the first half of 2021, whereas grasslands lost 10.9 grams of carbon per square meter. (Global Biogeochemical Cycles, https://doi.org/10.1029/2025GB008607, 2025)

—Saima May Sidik (@saimamay.bsky.social), Science Writer

Citation: Sidik, S. M. (2025), In the Arctic, consequences of heat waves linger, Eos, 106, https://doi.org/10.1029/2025EO250313. Published on 22 August 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

It took only 1.3 seconds for the Sagaing Fault to open a gash in Earth’s surface and shift it by 2.5 meters during the magnitude 7.7 Myanmar earthquake earlier this year. When video surveillance some 120 kilometers south of the earthquake’s epicenter caught the moment, the footage sent a shock wave of excitement through the global seismology community.

At first, Jesse Kearse, a geophysicist at Kyoto University, was simply in awe of the tectonic forces, but as he rewatched the video, he soon realized its scientific value. “Of all the instrument records we have of earthquakes from the past 100 years, most are from far away,” he said. This was the first real-time observation of a major rupture close to a fault.

Kearse and Yoshihiro Kaneko analyzed the video frame by frame using a technique called pixel cross correlation. Their findings, published in The Seismic Record, revealed the pulse-like nature of major earthquake propagation and the curvature of fault slip.

How Earthquakes Move Along a Fault

Seismologists have long understood that a fault doesn’t rupture all at once. Instead, it experiences a traveling, localized zone of slip, said David Wald, a geophysicist at the U.S. Geological Survey in Golden, Colo., who was not involved in the new research.

Wald’s work on the 1992 magnitude 7.2 Landers earthquake in California helped to establish that earthquakes propagate in pulses. But this work was “always a step removed from reality, modeling the rupture propagation process” as opposed to watching it in real time, he said.

“Seeing is believing.”

“Seeing is believing,” Wald said of the Myanmar footage. “We were all blown away by the video, which confirms how a short slip duration, large slip, and thus high slip velocity produce a large pulse of ground shaking.”

Analysis of the Myanmar earthquake video showed that the traveling slip zone was only several kilometers wide, even though the earthquake ultimately ruptured a more than 400-kilometer-long section of the fault. Pulse-like rupture is a more efficient way to move Earth’s massive crust, Kaneko noted. “This video provides the first visual confirmation of it occurring in real time.”

Although crumpled landscapes left by earthquakes have shown that seismic ruptures can cause permanent offsets of many meters, until now it wasn’t clear whether that movement happens within 1 or 2 seconds. “The historic record shows the offset but not how quickly that happened,” Kearse said. “It’s becoming clear that these pulse-like ground motions are really large amplitude, meters per second of ground velocity. For large buildings, that’s very difficult to engineer for.”

Curved Slip Movement along the Kekerengu Fault, which ruptured during the 2016 Kaikōura earthquake in New Zealand, left slickenlines on the wall of an outcrop. Credit: Kate Clark, Earth Sciences New Zealand

The video analysis was challenging because ground shaking caused the camera to tilt and wobble. But Kearse and Kaneko managed to isolate the fault motion by systematically analyzing stationary targets in the footage. To their surprise, they watched the slip curve before it settled into horizontal motion.

Geologists know that earthquakes leave curved scratch marks known as slickenlines on fault surfaces. In a previous study, Kearse and his colleagues described these grooves on exposed surfaces of the Kekerengu Fault, one of several that ruptured in New Zealand’s 2016 magnitude 7.8 Kaikōura earthquake. When they fed those data into a model, the team found a link between the curvature of slickenlines and the direction that a fault ruptured.

The analysis of the Myanmar earthquake footage delivered real-time evidence of this connection between slip curve and rupture direction. “What our new study contributes is a quantitative analysis of both the speed and direction of the curved slip while the rupture is actively unfolding,” Kaneko said.

The research “fortifies the slickenline story.”

The research “fortifies the slickenline story” and may help seismologists better anticipate the ground shaking likely to occur in future events, said John Vidale, an Earth scientist at the University of Southern California. This understanding is particularly important for faults with the potential to rupture in massive earthquakes, including California’s San Andreas Fault and New Zealand’s Alpine Fault. Such earthquakes would affect major population centers differently, depending on the direction in which the earthquake traveled.

The Myanmar video also highlights the potential of autonomous cameras as tools in seismology, according to Haiyang Kehoe, an Earth scientist who will be joining the University of Oregon in December. “The proliferation of home security systems and traffic cameras increases the likelihood that some portions of future earthquake ruptures will be recorded with a similar amount of clarity.”

For Laura Wallace, a geodetic scientist at the University of Texas and the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany, the work opens new potential for using slickenlines from paleoearthquakes to investigate whether a particular fault has a tendency to rupture in one direction or another. “Such insights would provide important information for future seismic hazard forecasts.”

—Veronika Meduna (@veronikameduna.bsky.social), Science Writer

Citation: Meduna, V. (2025), Video shows pulsing and curving fault behavior, Eos, 106, https://doi.org/10.1029/2025EO250307. Published on 21 August 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Editors’ Vox is a blog from AGU’s Publications Department.

Stemflow, or the flow of water along the surface of a plant’s stem, has been a subject of inquiry in forest hydrology since the latter half of the 1800s given its relevance to water balance studies. The consequences of stemflow to ecological and soil biogeochemical processes led to an influx of research in subsequent years.

Today, stemflow is a burgeoning research area for diverse groups of people because it sits at the nexus of the geosphere, atmosphere, and hydrosphere. Recent interest in the topic stems from an engineering and urban planning perspective as, despite its long history of study, research has not focused on the physics of how water moves down the stem and what forces control these actions.

A new article in Reviews of Geophysics takes the first step in exploring and defining the hydrodynamics of stemflow. Here, we asked the authors to give an overview of stemflow hydrodynamics, how scientists have applied established theory in new ways to explore this broadening field, and potential future research directions.

In simple terms, what is stemflow?

Stemflow is the aboveground flow of water along the exterior surface of a plant stem.

Stemflow is the aboveground flow of water along the exterior surface of a plant stem. It is initiated after precipitation intercepted by leaves and branches drains from outlying parts of the plant crown down the stem/trunk to the soil surface around the plant base. Unlike raindrops that pass unhindered through a plant canopy or penetrate it by dripping or splashing from vegetative surfaces (known as throughfall), stemflow experiences longer contact time with the surface of the stem.

On trees, this lengthened exposure of stemflow-bark interactions enables higher nutrient leaching and subsequent delivery of concentrated nutrients and water to roots. The funneling of enriched waters to the tree base is the primary reason that stemflow is a main contributor to what is termed ‘hot spots’ and ‘hot moments’ in biogeochemical cycling of near-trunk soils. This indicates that the input of water, solutes, particulates, and other matter are uneven in space and time with soils near tree trunks representing an area of disproportionately high rates of biogeochemical cycling.

What role does stemflow play in the broader environment?

Stemflow connects the atmosphere, biosphere, and geosphere. It links the canopy of a tree to the soil and acts as a pathway that delivers water and the substances it carries down the trunk to the ground. Along this path, water interacts with the bark and the organisms living on or within it, including fungi, bacteria, lichens, mosses, metazoans, and insects. For these reasons, stemflow has been traditionally studied in forest hydrology and forest ecology circles, but there is now elevated interest within the engineering and urban planning communities to quantify it.

For example, with respect to pollutant cycling, stemflow can account for some differences in the spatial patterning of radiocesium, a radioactive form of the element cesium, in near-trunk soils. In urban planning and stormwater design, for instance, stemflow could exacerbate stormwater runoff in areas without favorable soil conditions (i.e., paved areas, areas with compacted soils) where water could infiltrate. The role of trees in meeting different ecosystem services within broader green infrastructure plans is still being explored.

(a) Fluid movement on an inclined smooth plane showing how an initially uniform advancing front breaks down into zones of fast-moving regions (or fingering). The goal of hydrodynamics is to predict the conditions that lead to such instabilities based on force imbalances (here between gravitational effects and surface tension). (b) Similar network features to panel (a) of connected instabilities along a vertical concrete wall in a parking garage after a rainfall event. (c) Preferential paths of water movement along a vertical stem. (d) Water bubbling due to leaching of solutes as water moves along the stem. Such bubbling impacts how water properties (viscosity, surface tension, density) and the forces that depend on them are formulated. (e) The physics of water movement inside the stem (xylem and phloem) has been uncovered well before stemflow despite the fact that stemflow can be observed by the naked eye and its observation commenced well before those associated with the xylem and phloem. The complexity of the physics required for describing water movement along the exterior surface of the plant is one of the main reasons for this ‘knowledge lag.’ Credit: Katul et al. [2025], Figure 1

How do scientists observe and measure stemflow?

The first stemflow measurements were conducted by Karl Eduard Ney in 1870.  Later, in 1881, W. Riegler established a link between the arrangement of branches and leaves and the amount of water flowing down the tree trunk. Riegler’s work paved the way to a line of inquiry common in ecology: exploring relations between structure (in this case tree architecture, bark properties, etc.) and function (amount and chemical composition of water in stemflow, sustenance of life dwelling on bark surfaces, etc.).

Measuring stemflow is based on capturing the volume of water that flows down a tree stem or trunk during and after a rainfall event.

Measuring stemflow is based on capturing the volume of water that flows down a tree stem or trunk during and after a rainfall event. The water capturing mechanism involves attaching collars or gutters around the tree trunk. These capturing mechanisms direct water into a nearby collection system. The collection system is usually formed by a container or containers where changes in water volume within the container can be measured over time, which allows the calculations of flow rates and relate them to rainfall data.

The instrumentation used to record the changes in volume of water with time varies in time scale. Tipping-bucket gages and containers with automated pressure recording devices as well as optical methods have all been employed in field studies to track the volume of water changes in time. These devices enable determination of stemflow on time scales of a few minutes to multiple years. Stemflow measurements are certainly an area that can benefit from rapid advancements in instrumentation and dedicated facilities. Stemflow hydrodynamics, once completed, may also enable ‘in-silico’ (or computer modeling) studies addressing relations between ‘structure’ and ‘function.’

What is stemflow hydrodynamics?

Hydrodynamics is a branch of fluid mechanics concerned with the motion of fluids (especially water) and the forces acting upon them. The other key branch of fluid mechanics is hydrostatics, which deals with forces acting on fluids when the fluid is at rest (as may be the case for water behind a dam). Stemflow hydrodynamics is a subset of hydrodynamics that seeks to explore fundamental connections between water depth, velocity, and flow rates on stems in relation to the governing forces.

Stemflow hydrodynamics deals with three conservation laws: water mass (left), scalar mass (middle), and momentum (right). These conservation laws consider a small element repeated across the three panels featuring each conservation law.  For the conservation of mass, there is a certain mass per unit area (perpendicular to the flow direction) per unit time (known as flux) that enters and leaves (indicated by qin and qout), and the bark itself absorbs water (indicated by a sink Sw). The imbalance between these fluxes and sinks impacts the water depth (h) variation along the stem and in time as well as the velocity. The middle and right panels repeat such balances for scalars (where Sc represents leaching) and forces (wall friction, gravitational force and surface tension at the contact line between the waterfront, the atmosphere, and the bark surface). Credit: Katul et al. [2025], Figure 3

At any point on the stem where water flows, these forces are primarily classified as body forces (gravitational), surface forces (friction), and line forces (surface tension). Any imbalance between these forces cause water to accelerate when the driving forces (gravity) exceed the resistive forces or to decelerate when resistive forces exceed the driving forces. Describing the resulting flow rate and the forces acting on water as it traverses the stem remains a daunting challenge to be confronted by stemflow hydrodynamics. The force imbalance and the resulting acceleration/deceleration is mathematically expressed as a conservation of momentum equation much like Newton’s second law that states the net force imbalance per mass determines the acceleration of a solid object having a fixed mass.  

What is thin film theory and how can it apply to stemflow hydrodynamics?

Thin film theory is a branch of fluid mechanics that describes the depth and velocity of a thin layer of fluid moving over a surface. Its name derives from certain approximations to the conservation laws of mass and linear momentum when the film’s thickness is much smaller than the length or width of the domain (e.g. trunk height). It was utilized to find approximate solutions for seemingly intractable engineering problems that were otherwise difficult to solve, such as coating processes in industry (e.g., paint, polymer films), lubrication layers between surfaces, mucus transport in lungs and airways, tear films on eyes, microfluidics and lab-on-a-chip devices, among others. The theory also has an extensive history and usage in hydraulics and hydrology where it is referred to as the shallow water equations.

These equations were originally proposed in the 19th century by Adhémar Jean Claude Barré de Saint-Venant. The significance of these equations cannot be overstated as Saint-Venant was one of the 72notable French scientists and engineers whose names are inscribed on the Eiffel Tower in Paris (France). In hydrology and hydraulics, the shallow water equations are routinely used to describe unsteady flow in streams and rivers, flood routing, flood waves following a dam break, overland flow on hillslopes, estuarine and tidal modeling, among others. All these flow types are based on the so-called small slope approximation and do not account for line forces or surface tension. Stemflow, however, occurs on almost vertical stems and therefore does not satisfy the small slope approximation. Moreover, surface tension can play a role in the force balance as water traverses the stem. These factors may have played a role in why the Saint-Venant equations were overlooked in the study of stemflow.

What are the major unsolved or unresolved questions and where are additional research, data, or modeling efforts needed? 

There are numerous challenges that need to be addressed before a complete description of the governing equations of stemflow hydrodynamics can be declared. These challenges begin by expressing frictional and line forces as a function of velocity and depth, as well as formulating water losses to the bark interior as water travels across its surface. Below is a partial list of just three unresolved issues related to forces characterization and their connection to the local bark properties: 

Fluid Properties: The addition of surfactants due to plant residue (e.g., acids), dust particles (e.g., salt), or exuded sap (e.g., resin) can create foam or soap‐like flow to occur along the stem. These surfactants can alter water properties such as viscosity and surface tension in ways that await exploration. They can also introduce spatial gradients in interfacial properties such as surface tension that may lead to unbalanced planar stresses at the air-water interface that induce motion within the film.

Surface Tension: Much of the thin film theories represent surface tension as a static balance of all forces along the contact line between the bark surface, the moving waterfront, and the ambient air. However, in the case of an accelerating or decelerating water movement, additional terms disrupt the force balance along the contact line due to unsteadiness, inertia, and friction. These effects have not been quantified for bark surfaces. Surface tension also plays a key role in controlling the spatiotemporal evolution of traveling waves on the falling water sheet. It will be a challenging task to understand the effect of capillary forces on such nonlinear waves that are traveling on complex, nonstandard, and multiscale geometries such as a tree bark.

Breakdown of Sheet Flow: Thin film theory treats water movement as a sheet. However, protrusions and cavities within the bark disrupt the sheet flow representation. There are instances where water piles up in fissures and cracks – and is then suddenly released (jetting) or drips out, to contribute to stemflow volume elsewhere on the bark surface. The breakdown of the sheet flow approximation and what physics becomes appropriate when this breakdown occurs is not settled.

Breakdown of sheet flow due to the imbalance between surface tension (holding the water in cavities along the bark) and the weight of water piling up in cavities (pushing the water out). When the pile up force (or weight) exceeds the holding force (surface tension), the water can ‘drip’ or ‘jet’ out of cavities. When it jets out of cavities, the jetting water column may still break down into droplets whose size is larger than the holding cavity size. Credit: Katul et al. [2025], Figure 6

—Gabriel G. Katul (gaby@duke.edu; 0000-0001-9768-3693), Duke University, USA; Bavand Keshavarz (0000-0002-1988-8500), Duke University, USA; Amirreza Meydani (0000-0002-7932-1477), University of Delaware, USA; and Delphis F. Levia (0000-0002-7443-6523), University of Delaware, USA

Editor’s Note: It is the policy of AGU Publications to invite the authors of articles published in Reviews of Geophysics to write a summary for Eos Editors’ Vox.

Citation: Katul, G. G., B. Keshavarz, A. Meydani, and D. F. Levia (2025), Waterworks on tree stems: the wonders of stemflow, Eos, 106, https://doi.org/10.1029/2025EO255027. Published on 21 August 2025. This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Earth Surface

Cold regions with mountainous terrain can host a multitude of landslide hazards, including rock-ice avalanches. These mass movements are particularly dangerous, as the presence of ice can amplify the potential for the flow to travel exceptional distances. A better understanding of rock-ice avalanche mobility necessitates consideration of how the flow interacts with the material (e.g., snow, ice, and rock) that is encountered as it travels downslope.

Peng et al. [2025] develop a unique suite of small-scale physical experiments that consider variations in the ice content of the initial gravel-ice flow mixture, the slope angle along which the flow travels, and the type of erodible material that the flow overrides. The authors find that the flows exhibit higher mobility when overriding snow and ice is present compared to gravel and that, regardless of the erodible material type that the flows override, higher flow erosion rates correspond to higher flow mobility. This study highlights that the entrainment of snow, ice, and rock can significantly affect the mobility of rock-ice avalanches and is likely an important mechanism to consider when developing frameworks for hazard assessment.

Citation: Peng, C., Li, X., Yuan, C., & Huang, Y. (2025). Insights into the dynamics of rock-ice avalanches from small-scale experiments with erodible beds. Journal of Geophysical Research: Earth Surface, 130, e2025JF008303. https://doi.org/10.1029/2025JF008303

—Matthew A. Thomas, Editor, JGR: Earth Surface

Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: AGU Advances

The degree to which global warming will affect atmospheric dynamics and, therefore, extreme weather is still uncertain. Broadman et al. [2025] find a clever way to reconstruct the history of one dynamical pattern that occurs when the jet stream forms five peaks and troughs around the Northern Hemisphere (referred to as a wave5 pattern). When this pattern occurs and persists during May-June-July there is a higher likelihood of co-occurring compound climate events — for example combined heat and drought in the southeastern United States, China, and southern Europe, but wetter than normal in Northwest Canada and Spain.

The authors combine multiple lines of evidence, tree ring records, climate reanalyses and models, to reconstruct variations in the strength of the early summer wave5 pattern and extend them over the past millennium. They find decadal variations but no significant trends in the occurrence of wave5 related climate extremes. However, a demonstrated link between La Niña conditions the preceding winter could potentially help in predicting the potential in some regions for extreme weather the following summer.

Citation: Broadman, E., Kornhuber, K., Dorado-Liñán, I., Xu, G., & Trouet, V. (2025). A millennium of ENSO influence on jet stream driven summer climate extremes. AGU Advances, 6, e2024AV001621. https://doi.org/10.1029/2024AV001621

—Susan Trumbore, Editor, AGU Advances

Text © 2025. The authors. CC BY-NC-ND 3.0
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Source: Earth’s Future

Federal lands—which make up about 640 million acres, or 28%, of U.S. soil—are used for many purposes, including conservation, recreation, and extraction of resources such as coal. Greenhouse gas emissions are released throughout the life cycle of coal use, including during its mining, transport, and combustion.

Merrill et al. estimated the amount of coal production and coal-related greenhouse gas emissions from federal lands from 2024 to 2051. Specifically, they focused on emissions of carbon dioxide, methane, and nitrous oxide from 30 existing mines on federal lands (excluding Native American lands) in six states.

Active mines, and some abandoned mines, generate fugitive emissions, or unintended emission leaks, via venting and drainage. To calculate fugitive greenhouse gas emissions of underground mines, the team used average emissions data from the five most recent years available (2016–2020). The researchers calculated emissions from surface mines using a method developed by the U.S. EPA.

To estimate transportation-related emissions, they turned to resources such as power plant coal receipts and coal mine news releases to find information about how far and by what means coal was transported. The team used information about coal composition and mine characteristics, along with public reports, to estimate the most likely end uses of coal, such as cement production, conversion into coke (a fuel used in iron ore smelting and blacksmithing), or, most commonly, combustion.

From their analysis, the researchers estimated that between 2024 and 2051, coal production from federal lands will decline to 14.2% of 2023 production levels. The fastest rates of decline will occur between 2037 and 2048 because of the anticipated closure of a number of coal power plants. In the same time period, greenhouse gas emissions from coal mining on federal lands are projected to decrease 86% from 2024 estimates. Most of this reduction, roughly 95%, would come from reducing end point combustion of coal.

The team noted that their work was based on information that existed at the beginning of 2024 and that their findings are subject to possible changes in land management decisions. They suggest that these estimations can be helpful as part of domestic and global decisionmaking around greenhouse gas emissions and the future use of coal. (Earth’s Future, https://doi.org/10.1029/2024EF005735, 2025)

—Sarah Derouin (@sarahderouin.com), Science Writer

Citation: Derouin, S. (2025), By 2051, emissions from coal mining on federal lands could drop by 86%, Eos, 106, https://doi.org/10.1029/2025EO250305. Published on 20 August 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Editors’ Vox is a blog from AGU’s Publications Department.

By the middle stage of a scientist’s career, expertise and reputation have been established, creating space to test out fresh opportunities and expand one’s comfort zone. For three scientists who wrote or edited books as mid-career researchers, this professional stage was very much a “happy medium.” They describe honing their research interests, gaining more autonomy to mold their work life, and finding joy in new roles within and beyond academia. Among these new undertakings was writing or editing a book. In the second installment of three articles, scientists contemplate why a book project was the perfect addition to the dynamic mid-career stage of their professional journeys.

Gaye Bayrakci coedited Noisy Oceans: Monitoring Seismic and Acoustic Signals in the Marine Environment, a comprehensive review of the sources and impacts of different types of marine noise. Bethany Hinga authored Earth’s Natural Hazards and Disasters, a textbook about the science behind natural events and how to prepare for disasters. Tamie Jovanelly authored Iceland: Tectonics, Volcanics, and Glacial Features, which explores the dramatic forces that have shaped the Icelandic landscape. We asked these researchers what developments shaped their mid-career stage, how a book fit in with their other goals and responsibilities, and to what extent their books influenced their next steps.

How would you describe the middle stage of a scientist’s career?

It’s a stage where you’re trusted with responsibility, but you also have the freedom to shape your role.

GB: Mid-career is genuinely exciting. I’m no longer dealing with early-career uncertainty, but I’m still actively thinking about what I want to focus on in the years ahead. It’s a stage where you’re trusted with responsibility, but you also have the freedom to shape your role, whether that’s through supervision, strategic planning, or external engagement. That sense of possibility is one of the best parts of this stage. It is also when you begin to think more about legacy, considering the kind of contribution you want to make in the long run, and that adds meaning and motivation to the work.

BH: I think for a lot of scientists this is the time when research programs and professional relationships are well cemented, and they have a growing bench of graduate students they’ve trained and are moving out into the world to do great things. My experience was different. Ten years post-PhD, I was in higher education administration and starting to branch out into other areas of expertise related to that administrative work.

Why did you decide to complete a book project? Why at that point in your career?

TJ: I decided to write a book after leading a field studies course in Iceland for over a decade. Throughout this time, I noticed a significant gap in the textbook market. While several publications touched on Iceland’s volcanology at a basic level, none provided a comprehensive overview of the island’s tectonics, volcanics, and glacial features. Recognizing this need, I felt compelled to contribute a resource that would serve both educators and students in the field of geology. My prior course preparation not only solidified my understanding of Iceland’s unique geological landscape but also allowed me to organize this knowledge effectively.

It was a chance to do something creative rooted in my scientific discipline.

BH: I had a twelve-month position in Academic Affairs at my university and the students and faculty were only on campus for nine months. I had three months of the year with time on my hands and a deep desire to start on a book that had been simmering in my head for years. I also had incredibly talented colleagues who were willing to write chapters in areas I felt were important to include in the book, but I didn’t have the expertise or comfort level to write myself. It was a chance to do something creative rooted in my scientific discipline, and it was a welcome change of gears from my job during the academic year, which had nothing to do with my discipline.

GB: The idea came when someone in my professional network, Frauke Klingelhoefer, was invited by AGU to propose a book on short-duration or non-earthquake seafloor signals. She contacted me, and we quickly realized that a broader book on ocean noise would be more valuable. It is a timely topic, relevant to biology, climate, defense, and offshore infrastructure, yet still underrepresented in the literature. Frauke, being very busy, suggested we co-edit and encouraged me to take the lead. It felt like the right moment to take on a creative, community-focused project.

What were some benefits of doing a book as a mid-career researcher?

It helped me see connections across disciplines and engage with researchers I might not have otherwise worked with.

GB: Editing the book gave me a much broader view of how scientists use pressure and sound to study both the water column and the shallow subsurface. It helped me see connections across disciplines and engage with researchers I might not have otherwise worked with. It was also a chance to step back, reflect on my own work, and rethink my scientific direction. I’ve since started new collaborations and found ways to apply similar techniques in my projects. The process confirmed that there’s still so much space to grow at mid-career.

TJ: Writing a book as a mid-career researcher offers several significant benefits. First, at this stage in my career, I had successfully navigated key responsibilities toward earning promotion and tenure. With these milestones behind me, I had the freedom to pursue projects that genuinely interested me making the writing process very enjoyable. Second, after years of publishing scientific journal articles, I had honed essential skills in conducting literature searches, synthesizing scientific arguments, and formulating key questions. These competencies not only streamline the writing process but also bolstered my confidence as an author. I felt capable of presenting complex ideas in a manner that is accessible to a broader audience. Third, writing a book allowed me to establish myself as a thought-leader in my field. By compiling my insights and research findings into a cohesive monograph, I have solidified my reputation as an expert on specific topics. This has led to greater visibility within the academic community, opened doors with new collaborators, and presented countless speaking engagements and other professional opportunities.

What advice would you give to mid-career researchers who are considering writing or editing a book?

Writing a book is an excellent way for a mid-career researcher to fall in love with science again.

TJ: My advice for any mid-career researcher considering writing a book is to realize that you are not an expert before you write the book; you are an expert after you write the book. Tackling a book project with this mentality automatically provides you with some grace when you are asking questions that you don’t yet have the answers to. Writing a book is an excellent way for a mid-career researcher to fall in love with science again, and it will make you a better classroom teacher and science communicator as a result.

BH: This is really the perfect time in your career to take on a project of this type!

—Gaye Bayrakci (g.bayrakci@noc.ac.uk, 0000-0003-1851-5021), National Oceanography Centre, UK; Bethany Hinga (Beth.Hinga@Newberry.edu, 0000-0003-0694-5331), Newberry College, USA; and Tamie Jovanelly (tamiejovanelly@gmail.com, 0000-0002-4374-0266), Adventure Geology Tours, USA

This post is the second in a set of three. Learn about leading a book project as an early-career researcher. Stay tuned for the third installment.

Citation: Bayrakci, G., B. Hinga, and T. Jovanelly (2025), Mid-career book publishing: bridging experience with discovery, Eos, 106, https://doi.org/10.1029/2025EO255026. Published on 20 August 2025. This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). Text © 2025. The authors. CC BY-NC-ND 3.0
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Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Biogeosciences

The prevailing view of mammal activity in ecosystems is that they have marginal impacts to services like greenhouse gas emissions. However, that is not always the case, especially with large, feral ungulates. In northern Australia, the indigenous Yolŋu peoples connect and rely on coastal wetlands for spiritual connection, tourism, fisheries, and crocodile egg harvesting. These wetlands, however, suffer damage from invasive pigs and buffalo. The Yirralka Rangers of the region attempt to control these from the air.

Crameri et al. [2025] partnered with the local community to evaluate the impact of these feral ungulates on wetland greenhouse gas emissions and carbon stocks, an ecosystem service growing in value for climate change mitigation. Fenced enclosures allowed the authors to reveal a fourfold increase in carbon dioxide and methane emissions in unfenced areas, while fenced areas increased in belowground biomass with limited impact on soil organic carbon. The work demonstrates how research partnerships with local communities, as documented in the article’s Inclusion in Global Research statement, can support local land stewardship and contribute to global conservation and climate mitigation efforts.

Citation: Crameri, N. J., Mununggurr, L., Rangers, Y., Gore, D. B., Ralph, T. J., Pearse, A. L., et al. (2025). Feral ungulate impacts on carbon cycling in a coastal floodplain wetland in tropical northern Australia. Journal of Geophysical Research: Biogeosciences, 130, e2025JG009056. https://doi.org/10.1029/2025JG009056

—Ankur Desai, Associate Editor, JGR: Biogeosciences

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Water ice molecules are among the most common in the cosmos and influence the interior and exterior of many planetary bodies in our solar system. Glaciers shape parts of Earth’s surface, and dwarf planet Pluto, along with moons such as Europa, Ganymede, Titan, and Enceladus, have whole landscapes made up of ice alone, including boulders, mountains, and even volcanoes.

Under high-pressure or very low temperature conditions, ice forms different crystal structures than those that occur naturally on Earth. Identifying and measuring those structures on worlds such as Ganymede would provide unique data on the interiors of these celestial bodies, in the same way studying mantle rocks pushed to the surface on Earth reveals our planet’s deep geology.

In the lab, researchers can bombard ice with X-rays or neutrons to understand its structure. But such instruments aren’t practical to fly on spacecraft.

“The ices that we prepare in the lab only occur naturally in space.”

Now, new experiments conducted by Christina Tonauer and her colleagues at Universität Innsbruck in Austria show how to distinguish between ice structures using infrared spectroscopy. The analyses, published in Physical Review Letters earlier this summer, can be done using observations from NASA’s James Webb Space Telescope (JWST) or the European Space Agency’s JUICE (Jupiter Icy Moons Explorer) mission currently en route to Jupiter.

“The ices that we prepare in the lab only occur naturally in space,” said Tonauer, whose work combines her field of physical chemistry with her love for planets. “I’m also really interested in astronomy, and this is what hooked me to water ice.”

During Tonauer’s Ph.D. work in the early 2020s, JWST was still to be launched, but it was clear the infrared observatory would open avenues for studying the ice-covered moons of the outer solar system. When she and her collaborators delved into the literature, they realized that a lot of spectroscopic work on ice—research that largely predated the leaps in understanding gained from the Voyager and Cassini missions—considered infrared (IR) wavelengths longer than those JWST could measure.

It seemed fruitful to Tonauer and her colleagues to study the shorter-wavelength IR spectrum (near-IR) emitted by ice on these distant worlds.

Ice Maker, Ice Maker, Make Me Some Ice

As of 2025, 21 different phases of ice have been identified in laboratory experiments, although only one form exists under normal conditions on Earth. That form is called ice Ih (pronounced “ice one aitch”), where “h” refers to the hexagonal pattern the molecule’s oxygen atoms take when viewed from one direction.

The conditions that allow researchers to study other ice phases in the lab exist naturally on other planets and moons, however, and scientists have concluded the phases might exist there.

Ganymede and other worlds in the outer solar system likely have something akin to mantle dynamics, for example, but with ice instead of silicate minerals.

Ganymede’s mantle could be 800 kilometers thick and consist of several forms of ice that are known only from laboratory experiments on Earth. Tonauer and her collaborators selected ice V and ice XIII for their study, because they form under the high pressures and low temperatures present inside Ganymede and other moons. These phases have the same arrangement of oxygen atoms, but different orientations of hydrogen atoms: In ice V, hydrogen is jumbled around, whereas hydrogen in ice XIII is structured.

Making these types of ice in the lab requires cooling liquid water with liquid nitrogen under about 5,000 atmospheres (500 megapascals) of pressure. As long as the samples are kept cold after forming, Tonauer noted, they don’t require high pressure to remain stable because the atoms move so slowly.

However, that slow motion still stretches the bonds between molecules, a vibration that produces IR signals. Using spectroscopy to interpret the emissions, Tonauer and her colleagues discovered that these signals are different for ice V and ice XIII. That difference provided the first experimental demonstration of using IR to distinguish hydrogen configurations within different phases of ice. It also highlighted a way to identify them remotely.

The researchers used a JWST simulator to show that a few hours of observation would be enough to distinguish between these ice phases on Ganymede.

A Peek at Deep Ice

The stability of these ice phases is key to understanding their potential presence on the surface of Ganymede: The phases require high pressure to form, but if brought to the lower-pressure surface, they can maintain their exotic crystal structure indefinitely. In that way, the presence of ice V or XIII would provide details about the icy mantle that would otherwise be inaccessible.

Past and present missions to the Jovian system have clearly indicated that Ganymede’s interior contains a liquid water ocean sandwiched between ice layers, but the ices’ crystalline structures, as well as how the layers move and evolve, have not been verified by empirical data. According to models of icy moon interiors, the high-pressure environment should produce ice V, which phenomena such as the tidal force from Jupiter might bring to the surface.

“We can now potentially detect subtle structural differences on icy moons without needing a lander or sample return.”

These new infrared spectroscopy analyses show how to distinguish between ice Ih, ice V, and ice XIII—not to mention amorphous ice, which lacks a clear crystal structure—without having to return samples to Earth for laboratory analysis (a prohibitively expensive proposition). The method could provide an observational way to verify or refute models of interior ice dynamics, sharpen our picture of Ganymede’s internal structure, and help us understand how different flavors of ice behave and interact with each other in a natural environment.

“We can now potentially detect subtle structural differences on icy moons without needing a lander or sample return,” said Danna Qasim, a laboratory astrophysicist at the Southwest Research Institute in Texas who was not involved with the new study.

Qasim pointed out that if the grains of these ices are small and jumbled together, it might be difficult to extract their IR signature. As other recent research has shown, amorphous ice in space likely contains chunks of crystalline ice joined together at odd angles, which also might make identification more difficult.

However, the new method seems promising and could well answer vital questions about the internal structure of icy moons.

“We invest billions of dollars in these spectacular space missions,” Qasim said. “If we want to truly understand what the data is telling us about these enigmatic beautiful worlds, it is absolutely necessary to have laboratory experiments like the ones performed here.”

—Matthew R. Francis (@BowlerHatScience.org), Science Writer

Citation: Francis, M. R. (2025), Infrared instruments could spot exotic ice on other worlds, Eos, 106, https://doi.org/10.1029/2025EO250303. Published on 19 August 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
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This is an authorized translation of an Eos article. Esta es una traducción al español autorizada de un artículo de Eos.

No hace mucho, en un día de verano, 10 personas se reunieron para comer queso en nombre de la ciencia. Degustaron pequeñas porciones de Cantal, un queso firme de leche de vaca producido históricamente en el centro-sur de Francia, y evaluaron más de 25 atributos que incluyeron el color, el olor, el sabor, el aroma y la textura. La degustación era sólo uno de los componentes de un estudio más amplio sobre los efectos del cambio de la dieta de las vacas, del pasto al maíz, debido a la industrialización y el cambio climático. Los nuevos resultados subrayan la importancia de mantener al menos parte de la hierba en la dieta de las vacas. Los nuevos hallazgos resaltan la importancia de mantener al menos algo de pastos en la dieta de las vacas.

“Su fisiología y tracto digestivo están hechos para digerir pasto”.

Las vacas, con sus cuatro bolsas estomacales, están preparadas evolutivamente para consumir pastos y extraer todos los nutrientes posibles de ese forraje. “Las vacas son herbívoras”, afirma Elisa Manzocchi, investigadora láctea de Agroscope en Posieux (Suiza), que no participó en la investigación. (Agroscope es una organización gubernamental suiza dedicada a la investigación agrícola). “Su fisiología y tracto digestivo están hechos para digerir pasto”.

Pero en todo el mundo, los bovinos se alimentan cada vez más con un dieta basada en maíz a medida que prolifera la ganadería a escala industrial – a menudo es más fácil, más eficiente y escalable alimentar a las vacas con un comedero en lugar de permitirles forrajear en un pastizal.

El cambio climático también está impulsando este cambio. Incluso en regiones en las que por bastante tiempo han llevado a las vacas a pastizales verdes, los ganaderos se enfrentan a la escasez de pasto en verano debido a las sequías. Así ocurre en Marcenat, lugar donde se encuentra una granja experimental del Instituto Nacional de Investigación para la Agricultura, la Alimentación y el Medio Ambiente (INRAE), explicó Matthieu Bouchon, científico especializado en cría de animales de ahí. El verano hace más calor que antes, pero sigue lloviendo mucho en primavera, afirmó. “Las condiciones son perfectas para el cultivo de maíz”.

Ver campos de maíz en Marcenat, una región montañosa del centro-sur de Francia a una altitud de 1,000 metros, es desconcertante, dijo Bouchon. “No es algo a lo que estamos acostumbrados”.

Bouchon y sus colegas del INRAE, dirigidos por la microbióloga Céline Delbès, investigaron recientemente cómo la modificación de la dieta de las vacas tiene efectos secundarios en la cantidad, la calidad, el valor nutricional, y el sabor de su leche y el queso resultante. En trabajos anteriores se habían comparado los resultados de dietas a base de pasto y maíz, dijo Manzocchi, pero esta investigación es particularmente exhaustiva. “Es uno de los primeros estudios en los que se analizaron muchos parámetros”.

Del suelo al pasto, del pasto a la vaca, y de ahí a la leche y al queso

El equipo se centró en 40 vacas Prim’Holstein y Montbéliarde, dividiéndolas en dos grupos: uno alimentado con una dieta basada principalmente en pastos y otro con una dieta basada en el maíz con cierto acceso a pastar forraje. Después de dos meses, la mitad de las vacas del primer grupo comenzó a recibir una dieta con menos pasto, y a la mitad de las vacas del segundo grupo se les negó por completo el acceso al pasto. El resultado fue una cohorte de cuatro grupos de bovinos que, durante casi tres meses más, comieron aproximadamente un 75 %, 50 %, 25 % y 0 % de pasto, respectivamente.

A lo largo del experimento, Delbès y sus colaboradores recogieron muestras de leche dos veces por semana (las vacas se ordeñaban dos veces al día), muestras de suelo de los pastizales e incluso muestras de las ubres de las vacas. El objetivo era comprender mejor cómo un cambio en la dieta inducido por el cambio climático se traduce en cambios en los atributos de la leche de un rebaño y, en última instancia, en el queso. “Había muchas cosas en este experimento”, dijo Bouchon.

Los investigadores solicitaron la ayuda de una quesería cercana a la granja para producir pequeñas rondas de queso Cantal, de aproximadamente medio kilogramo cada uno, utilizando leche de las vacas de cada uno de los cuatro grupos. Los quesos se maduraron durante 9 semanas antes de ser servidos a un panel de catadores entrenados en la degustación de quesos tipo Cantal.

Conservar el pasto

En consonancia con hallazgos anteriores, los investigadores descubrieron que el queso elaborado con leche de vacas alimentadas principalmente con pastos era más sabroso y tenía niveles más altos de ciertos ácidos grasos en comparación con los quesos producidos a partir de vacas alimentadas principalmente con maíz. Sin embargo, las vacas alimentadas con dietas con una mayor proporción de pastos también producían menos leche en relación con la cantidad de alimento que consumían, señaló el equipo.

En general, Delbès y sus colaboradores descubrieron que el cambio de una dieta con un 25% de pasto forrajeado a una con un 0% de pasto forrajeado era más perjudicial para la calidad nutricional y sensorial del queso, que el cambio de una dieta con un 75% de pasto forrajeado a una dieta con un 50% de pasto forrajeado.

“Es sorprendente que sólo una cuarta parte de la dieta pueda [influir] tanto en la calidad sensorial del queso”.

El hallazgo sugiere que mantener al menos una mínima cantidad de hierba fresca es fundamental para garantizar la calidad del queso, afirmó Delbès.

“Es sorprendente que sólo una cuarta parte de la dieta pueda [influir] tanto en la calidad sensorial del queso”, dijo Manzocchi. Pero tal vez ese hallazgo debería tranquilizar a los productores de queso tradicionales que ya no pueden alimentar a sus rebaños con una dieta basada principalmente en pasto, agregó. “Quizás sea una buena noticia”.

Delbès y su equipo aún no han terminado con sus rebaños Prim’Holstein y Montbéliarde. El trabajo futuro se centrará en examinar cómo los microbios presentes en el suelo y las zonas de descanso de las vacas, por ejemplo, se correlacionan con los microbios presentes en el intestino humano después del consumo de queso.

—Katherine Kornei (@KatherineKornei), Escritora de ciencia

This translation by translator Stephanie Segura (@StephSeg_05) was made possible by a partnership with Planeteando y GeoLatinas. Esta traducción fue posible gracias a una asociación con Planeteando and GeoLatinas.

Text © 2025. The authors. CC BY-NC-ND 3.0
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Following the passage Typhoon Podul, the lake created by this massive landslide has now grown considerably. Overtopping is expected in October, although could occur sooner if further heavy rainfall occurs.

The landslide-dammed lake behind the the enormous 21 July 2025 rock avalanche in the Matia’an valley, in Wanrong township in eastern Taiwan continues to fill. Meanwhile, the landslide itself is evolving with time. This is a Planet Labs image of the site soon after the main rock avalanche occurred:-

Planet Labs image showing the site of the 21 July 2025 landslide in the Matia’an valley in Wanrong township, Taiwan. Satellite image copyright Planet Labs , used with permission. Image dated 25 July 2025.

Whilst this is the most recent satellite image (note that the right hand side is the older image):-

Recent Planet Labs image showing the site of the 21 July 2025 landslide in the Matia’an valley in Wanrong township, Taiwan. Satellite image copyright Planet Labs, used with permission. Image dated 18 August 2025.

And here is a slider so that you can compare the two images:-

Image copyright Planet Labs.

This area received very heavy rainfall as a result of the passage of Typhoon Podul. This has driven a number of changes. Perhaps most obviously, the lake is now very considerably larger. This will continue to grow over the coming weeks until overtopping occurs.

Second, as I noted in my original post, the landslide generated a large volume of dust which had settled around the deposit, especially to the south. This has now been washed away.

Thirdly, there have been more failures from the rear scarp of the landslide, so the landslide deposit has evolved.

And finally, the heavy rainfall has driven some erosion of the finer-grained portions of the landslide deposit.

It is also worth noting that a few other, smaller, lakes have now formed on the landslide. The largest of these is about 250 x 200 metres, so not insignificant.

On 14 August 2025, etaiwan.news posted an article in Mandarin about the landslide. It noted that the Taiwan Government has authorised funding to “develop disaster mitigation, monitoring, evacuation, and engineering plans”. This includes the development of an evacuation plan, but also “evaluation and planning, excavation of spillways, construction of embankments, bed consolidation, etc., to reduce the risk of dam collapse and protect downstream areas”.

The Hualien Branch of the Forestry and Conservation Department has released these two images of the lake at the site of the in the Matia’an valley:-

The deposit of the 21 July 2025 landslide in the Matai’an valley in Wanrong township, Taiwan. Image by provided by Hualien Branch of the Forestry and Conservation Department/Wang Zhiwei Hualien Fax.

The deposit of the landslide is well-captured, with the lake in the background. This is the same site from the lake looking towards the toe:-

The lake formed by the 21 July 2025 landslide in the Matai’an valley in Wanrong township, Taiwan. Image by provided by Hualien Branch of the Forestry and Conservation Department/Wang Zhiwei Hualien Fax.

Immediately after the typhoon, the lake had reached 43% of its storage capacity with a freeboard of 55 metres. Assuming that no further typhoons affect this area, and in the absence of the construction of a spillway, overtopping is likely to occur in October.

Reference

Planet Team 2025. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/

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