EOS

Successfully predicting earthquakes sounds like a dark art.

However, new research hints it may be possible: Sediment cores extracted from the Pacific seafloor suggest that two major fault systems along the western coast of the United States and Canada might be partially synchronized. After an earthquake on the southern part of the Cascadia subduction zone, an earthquake soon after on the northern part of the San Andreas fault appears to occur roughly half of the time, the new findings reveal. These results, published in Geosphere, provide evidence of stress triggering, which has long been invoked to explain how activity on one fault might lead to activity on another nearby.

Fault zones persist across wide swaths of our planet, but the one that stretches onshore and offshore from California to British Columbia, Canada, is particularly complex. The vertical strike-slip San Andreas fault, in the south, intersects the Cascadia subduction zone off the coast of Northern California at a point known as the Mendocino Triple Junction.

There’s an amalgam of different types of large, active faults, and the Mendocino Triple Junction itself is migrating northward, said Chris Goldfinger, an earthquake geologist at Oregon State University in Corvallis. “It’s a very complicated situation.”

Earthquake Here, Earthquake There

Researchers have long wondered whether the northern region of the San Andreas fault and the southern part of the Cascadia subduction zone might be affecting one another. The idea isn’t far-fetched: Scientists know that earthquakes, which result from sudden releases of stored-up energy on a fault, relieve stress on one part of a fault but often do not make that stress disappear. “When it ruptures, [a fault] relieves the local stress. But then it transfers stress to other things around it,” said Goldfinger. Such stress transfer could, in turn, trigger activity on another nearby fault.

In 2008, Goldfinger and his colleagues published a study of earthquakes along the northern San Andreas and Cascadia subduction zone. To determine when the earthquakes happened, the team used radiocarbon dating of turbidites, which are sedimentary deposits left on the seafloor when ground shaking causes underwater landslides. The researchers found several apparent pairs of earthquakes that seemed to have occurred around the same time—that is, within decades or centuries of one another. However, the significant age uncertainties precluded drawing any definitive conclusions about paired earthquakes, Goldfinger said.

Mysterious Turbidites

Since then, Goldfinger and his collaborators have obtained more turbidite records from sediments in the ocean and also analyzed inland sediments from places like Lake Merced near San Francisco. With those new data, which stretch back roughly 3,100 years, in hand, the team returned to the question of paired earthquakes. The researchers also revisited a mystery that had been bothering them since the late 1990s: Why did some turbidites collected from near the Mendocino Triple Junction appear to be upside down?

“They had all of the sand at the top, which is not where it should be.”

Turbidites are layers of sand, mud, clay, and silt that typically are coarsest near the bottom and become finer grained at the top. That’s because gravity causes the coarsest particles—the sand—to settle out first and smaller particles to be deposited later as the current slows down. But many of the turbidite beds recorded in cores from near the Mendocino Triple Junction appear to be capped with sand, rather than finer sediment. That’s unexpected, said Goldfinger. “They had all of the sand at the top, which is not where it should be.”

It’s taken more than 2 decades for the team to finally arrive at an explanation for those anomalous turbidites.

They are, in fact, two turbidite beds, Goldfinger and his colleagues concluded. The sand on top is actually a second turbidite bed formed close to an earthquake source whose finer particles were carried away and deposited at more distant locations.

The researchers furthermore inferred that these so-called doublet turbidites were created by two different earthquakes occurring on different fault systems—one in the Cascadia subduction zone and one on the San Andreas fault. The tip-off was that the occurrence of doublet turbidites systematically decreases with increasing distance from the Mendocino Triple Junction. The San Andreas–derived turbidite beds fade away to the north, and Cascadia-derived turbidite beds fade away to the south. That’s expected because shaking from San Andreas earthquakes will be weaker the farther north one goes and shaking from Cascadia earthquakes will correspondingly be weaker the farther south one goes.

“These doublets should fade in a specific way, and they do,” said Goldfinger.

The team found that slightly more than half of the 18 turbidites they studied in the southern Cascadia subduction zone were closely associated in time with turbidites from the northern San Andreas. In those 10 cases, the median ages of the earthquakes inferred from radiocarbon measurements differed from their associated quake on the other fault system by roughly 60 years, which is about equal to the data’s uncertainty. Eight of those pairs furthermore exhibited a doublet structure, indicating that they occurred especially close together in time.

The similar timing and unique stacking pattern of the doublets suggest that Cascadia earthquakes generate regional stresses that trigger subsequent earthquakes on the northern San Andreas fault.

These findings convincingly demonstrate that the northern San Andreas and the southern Cascadia subduction zone are at least partially synchronized, said Kathryn Materna, a geophysicist at the University of Colorado Boulder not involved in the work. “Seeing half of them correlated on opposite sides of the triple junction is a pretty striking correlation,” she said. Because these faults tend to unleash earthquakes at different rates, there’s no reason their events should line up closely in time, said Materna. “They’re different systems with different recurrence intervals.”

Patiently Ducking and Covering

“The best fit to the data, by far, is to have Cascadia go first.”

Goldfinger and his colleagues believe that in cases of paired earthquakes, Cascadia is the one leading the charge. “The best fit to the data, by far, is to have Cascadia go first,” said Goldfinger.

Understanding why will take some modeling work. It’d also be interesting to dig into whether a Cascadia event of a certain magnitude is necessary to unleash shaking on San Andreas, he said. “It makes sense that there must be a triggering threshold.”

These findings suggest that a large Cascadia earthquake might be followed by ground shaking on the San Andreas. But ducking and covering after Cascadia lets loose could require some patience. The timing between paired earthquakes likely varies substantially, Goldfinger said. “It could be anything from minutes to decades.”

—Katherine Kornei (@KatherineKornei), Science Writer

Citation: Kornei, K. (2025), When Cascadia gives way, the San Andreas sometimes follows, Eos, 106, https://doi.org/10.1029/2025EO250419. Published on 12 November 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.

In 2008, NASA’s now-departed Cassini spacecraft made its fastest flyby of Enceladus, the moon of Saturn that’s spewing its subsurface ocean into space. A new analysis of data from that flyby has revealed a bevy of complex organic compounds that hadn’t been detected before and confirmed the origin of several previously known organics. The speed at which the flyby occurred, a zippy 18 kilometers per second, helped convince the researchers that the organics truly originated from Enceladus’s interior ocean and were not a product of postejection space weathering.

When combined with the slate of previously detected organic compounds, “these new organics could support chemical networks or chemical pathways that potentially could lead to biologically relevant compounds,” said Nozair Khawaja, lead researcher on this discovery and a planetary scientist at Freie Universität Berlin in Germany.

Connecting Chemistries

Enceladus emits plumes of water from its subsurface ocean through icy cracks near its south pole. Enough material has been released into space to create a ring around Saturn called the E ring. During its 13 years exploring the Saturn system, Cassini collected and analyzed multiple samples from the E ring and discovered a wide variety of organic and inorganic molecules, including aromatics and oxygen-bearing species, that hinted at complex chemistry happening within Enceladus.

“If you capture some particles in the E ring, that means, indirectly, you are sampling the subsurface ocean.”

“If you capture some particles in the E ring, that means, indirectly, you are sampling the subsurface ocean,” Khawaja said.

However, planetary scientists have debated whether all of the organic compounds discovered in E ring material could truly be traced back to the Enceladean ocean. After all, material sits in the E ring for years, and the material’s chemistry may have been altered through exposure to radiation from Saturn and the solar system, a process called space weathering.

Material ejected from Enceladus creates Saturn’s E ring, imaged here by Cassini in 2006. Credit: NASA/JPL/Space Science Institute

But Cassini didn’t just fly through Saturn’s rings. It also flew directly through Enceladus’s plumes. During those flybys, the spacecraft’s onboard Cosmic Dust Analyzer (CDA) collected and measured spectra from freshly ejected material. Grains of material entered the CDA collector and shattered into chemical constituents—mostly water ice with smatterings of other molecules. The CDA measured chemical spectra and reported what those grains were made of.

The trouble is that water molecules are very sticky, Khawaja explained. After shattering, ice molecules quickly cluster around and shield other molecules from detection. The slower the grains traveled through the instrument, the less time CDA had to spot those other compounds, which were the ones that scientists were most interested in decoding.

Previous analyses of Enceladus and E ring flybys, most of which occurred at relative speeds less than 12 kilometers per second, detected five of the six elements essential for Earth’s biology—the CHNOPS elements—but other materials remained elusive.

Speed Is Everything

Luckily, Cassini’s fifth Enceladus flyby was particularly speedy. Plume material traveled through the CDA at 18 kilometers per second. Analysis of data from that flyby, conducted by Khawaja and his team, revealed that the freshly ejected ice grains contained many of the same compounds that had previously been found in E ring material.

New models suggest that organic molecules could originate in hydrothermal vents at the base of Enceladus’s ocean, float upward toward the bottom of the moon’s ice shell, and condense onto ice grains as they travel through vents, before being ejected into space. Credit: NASA/JPL-Caltech

“These new particles, they were very young in age and very fresh material,” Khawaja said. “That means, if we observe in these fresh grains the same compounds [seen] in the E ring grains, which are months or many years old, that means that those compounds are actually coming from the subsurface of Enceladus.”

Because the material collected in this flyby did not have time to be altered by space radiation, these chemical commonalities “effectively rule out” space radiation or another process external to Enceladus as the source of complex organic material in the E ring and Enceladus’s ocean, explained Alexander Berne.

The results “indicate that endogenic processes, such as hydrothermal activity, i.e., energy-releasing interactions between silicate rock and water, form the observed chemistry,” Berne said. “This hydrothermal activity is potentially a key process for sustaining metabolic reactions to support astrobiology within Enceladus,” like black smokers near Earth’s mid-ocean ridges. Berne, a planetary scientist at the California Institute of Technology in Pasadena, was not involved with this research.

New Ingredients in the Soup

The swiftness of this particular flyby also enabled the CDA to measure the spectra of several previously undetected complex organic compounds before they were shielded behind an icy curtain. These compounds, including oxygen- and nitrogen-bearing species, aryls, alkenes, and ethyls, strengthen the theory that they were generated through geochemical processes at the base of the Enceladean ocean.

“The new compounds confirm that organics are present in the subsurface ocean and may indicate more complex, potentially hydrothermal processes there,” said Larry Esposito, a planetary scientist at the University of Colorado Boulder who was not involved with this research. “The new findings are consistent with the likely habitability of the ocean, which may resemble a complex organic ‘primordial soup.’”

These results were published in Nature Astronomy in October.

Khawaja cautioned that these newly detected organics do not mean that life exists in Enceladus’s ocean or that life is an inevitable result of mixing together this primordial soup. Continued analysis of archival Cassini data, bolstered by future laboratory experiments, could reveal the many potential outcomes of this chemical mixture and could piece together its origin story.

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

Citation: Cartier, K. M. S. (2025), Speedy flyby adds new organics to Enceladus’s “primordial soup,” Eos, 106, https://doi.org/10.1029/2025EO250416. Published on 12 November 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.

In August 2025, I recorded 104 fatal landslides leading to 2,365 fatalities, a record total number of landslides for August.

Loyal readers will know that each year, August is one of the two peak months for fatal landslides. In 2025, I recorded 104 fatal landslides leading to 2,365 fatalities (but please see below as I have severe doubts about the latter number).

This is an unusually high level of loss both in terms of the number of fatalities and the number of events.

This is the monthly total number of landslides for 2025 to the end of August:-

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

Loyal readers will also be aware that I like to use pentads (five day blocks) for inter-annual comparisons. This is the 2025 plot to pentad 49 (2 September 2025):-

The number of fatal landslides to 2 September 2025, displayed in pentads. For comparison, the long term mean (2004 to 2016) from Froude and Petley (2018) and the exceptional year of 2024 are also shown.

The graph demonstrates that to the end of August, 2025 was running a very long way above the long term mean number of landslides, and indeed was close to the absolutely exceptional number recorded in 2024.

The number of fatal landslides in August 2025 was dominated by events in South Asia, and in particular in India. That will need further analysis in due course. In terms of fatalities, the total was driven by the 31 August 2025 landslide at Tarasin in Sudan, which is reported to have killed 1,573 people. However, as I noted in a blog post, I have severe doubts about this total. At this stage, I do not have a reliable alternative total, so I have included the number as reported locally.

In terms of the number of fatal landslides, 2025 had the highest August total in my dataset. The previous highest total was 78 in 2018.

August 2025 was the third warmest August globally in the instrumental record, but it was cooler than both 2023 and 2024. In this case, it appears that the rainfall pattern from the summer monsoon in South Asia has had a major impact.

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
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

A weak spot in Earth’s protective magnetic field is growing larger and exposing orbiting satellites and astronauts to more solar radiation, according to more than a decade of measurements by three orbiting observatories.

“The region of weak magnetic field in the South Atlantic has continued to increase in size over the past 11 years.”

The observations by the European Space Agency’s Swarm trio of satellites found that Earth’s already weak magnetic field over the South Atlantic Ocean—a region known as the South Atlantic Anomaly (SAA)—is getting worse and that it has grown by an area half the size of continental Europe since 2014. At the same time, a region over Canada where the field is particularly strong has shrunk, while another strong field region in Siberia has grown, the measurements show.

“The region of weak magnetic field in the South Atlantic has continued to increase in size over the past 11 years since the launch of the Swarm satellite constellation,” explained Chris Finlay, a geomagnetism researcher at the Danmarks Tekniske Universitet. “Although its growth was expected based on early observations, it is important to confirm this change in Earth’s magnetic field is continuing.” Finlay is the lead author of a new study published in the journal Physics of the Earth and Planetary Interiors that analyzes data from the Swarm satellites.

Geomagnetic Field

The three satellites were launched in 2014 to precisely monitor magnetic signals from Earth’s core and mantle, as well as from the ionosphere and magnetosphere. Earth’s magnetic field (technically, the “geomagnetic field”) is thought to be generated by a rotating core of molten iron, roughly 2,900 kilometers, or 1,800 miles, beneath our feet. But the strength of the field changes continuously, and scientists are still learning about its exact mechanisms.

“Satellites experience higher rates of charged particles when they pass through the weak field region…astronauts will also experience these charged particles.”

The geomagnetic field protects life on Earth’s surface from harmful charged particles in solar radiation. We can see the effects of charged particles from the Sun interacting with the geomagnetic field in the upper atmosphere during aurorae such as the northern lights.

And because it extends into space, the geomagnetic field also protects orbiting spacecraft, including most satellites and the International Space Station (ISS). However, the study authors warn that spacecraft—and spacefarers—that enter the South Atlantic weak spot during their orbits of our planet could now be exposed to more radiation.

For spacecraft hardware, this radiation could cause more malfunctions, damage, or even blackouts. “The main consequence is for our low-Earth-orbit satellite infrastructure,” Finlay said. “These satellites experience higher rates of charged particles when they pass through the weak field region, which can cause problems for the electronics.”

Danger to Astronauts

People in orbit will also face higher risks from radiation, including a greater chance of DNA damage and of suffering cancer during their lifetimes. “Astronauts will also experience these charged particles, but their times in orbit are shorter than the lifetime of most low-Earth-orbit satellites,” Finlay said. (On average, astronauts on the ISS spend about 6 months in low Earth orbit, but satellites typically spend more than 5 years there—about 10 times as long.)

The geomagnetic field is relatively weak compared with more familiar forms of magnetism: Its intensity ranges from about 22,000 to 67,000 nanoteslas. In comparison, a typical refrigerator magnet has an intensity of about 10 million nanoteslas.

In the SAA, the geomagnetic field’s intensity is lower than 26,000 nanoteslas. According to the study, the region’s area has grown by almost 1% of the area of Earth’s surface since 2014. The weakest point in the SAA now measures 22,094 nanoteslas—a decrease of 336 nanoteslas since 2014.

In the region of strong geomagnetic field over northern Canada, the intensity is greater than 57,000 nanoteslas. The study found that the area has shrunk by 0.65% of the area of Earth’s surface, while its strongest spot has fallen to 58,031 nanoteslas, a drop of 801 nanoteslas since 2014. In contrast, a strong field region in Siberia has grown in size, increasing in area by 0.42% of Earth’s surface area, with the maximum field intensity increasing by 260 nanoteslas since 2014 to 61,619 nanoteslas today.

Scientists have discovered that the weak region in Earth’s magnetic field over the South Atlantic—known as the South Atlantic Anomaly—has expanded by an area nearly half the size of continental Europe since 2014. Credit: ESA (Data source: Finlay, C.C. et al., 2025)

These changes in the Northern Hemisphere were unexpected, Finlay said. “It is related to the circulation patterns of the liquid metal in the core, but we are not certain of the exact cause,” he said.

The study did not, however, find any sign of an impending magnetic field reversal. Earth’s magnetic field has already reversed hundreds of times, but “we know from paleomagnetic records that Earth’s magnetic field has weakened many times in the past, displaying weak field regions like the South Atlantic Anomaly, without reversing,” Finlay said. “We are more likely seeing a decade to century timescale fluctuation in the field.”

“Hardened” Spacecraft

The heightened danger from solar radiation to satellites and astronauts passing over the SAA could be mitigated by ensuring that spacecraft are “hardened” to withstand it, Finlay said: “Since the weakness is growing, the satellites will experience such effects over a larger area, [so] this should be taken into account when designing future missions.”

Geophysicist Hagay Amit of Nantes Université in France, who wasn’t involved in the latest study but who has studied the SAA, noted that several scientists have proposed possible reasons for the observed changes in the geomagnetic field, but the actual mechanisms remain unknown. “Overall, [the authors] convincingly demonstrated that continuous high-quality geomagnetic measurements are crucial for providing vital insights into the dynamics in the deep Earth,” he told Eos in an email.

—Tom Metcalfe (@HHAspasia), Science Writer

Citation: Metcalfe, T. (2025), A weak spot in Earth’s magnetic field is going from bad to worse, Eos, 106, https://doi.org/10.1029/2025EO250417. Published on 10 November 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.

Source: Geophysical Research Letters

The way clusters of differently sized water droplet populations are distributed within clouds affects larger-scale cloud properties, such as how light is scattered and how quickly precipitation forms. Studying and simulating cloud droplet microphysical structure is difficult. But recent field observations have provided crucial, centimeter-scale data on cloud droplet size distributions in stratocumulus clouds, giving researchers an opportunity to better match their models to reality.

The simulations of characteristic droplet size distributions that those models are providing are likely too uniform, say Allwayin et al. This muddled microphysical structure could be leading cloud simulations, and the climate models that use them, astray.

The authors compare the new observed data on cloud microphysical structure with results from large-eddy simulations (LES) of stratocumulus clouds. At convective scales, the model showed intriguing correlations between droplet cluster characteristics and overall cloud physics. For example, regions of the clouds dominated by drizzle tended to have larger drops but not necessarily more total water content, and the updraft regions of clouds tended to have smaller drops and a narrower distribution of droplet size.

However, across larger spatial scales, the characteristic droplet size distributions in the model looked very similar across different parts of a cloud. This diverges sharply from the observations, which show that the size distributions vary across large-eddy scales within the cloud.

One explanation could be that the process of entrainment—in which drier air is introduced into a cloud and causes evaporation—is not well resolved in these models, the authors say, noting a relationship between observations of characteristic droplet size distributions and local entrainment rates. In addition, models often assume that boundary layer properties such as surface fluxes and aerosol types are uniform across clouds.

The authors argue that a better understanding of cloud microphysics and its link to entrainment and boundary fluxes is needed to advance atmospheric modeling. The LES runs in this study are idealized cases, the researchers add, which should be kept in mind when interpreting their results. Future work should focus on understanding the role of horizontal gradients in aerosol concentrations, as well as on improving model entrainment layers, the authors suggest. Lagrangian schemes in LES models could hold more promise for this work. (Geophysical Research Letters, https://doi.org/10.1029/2025GL116021, 2025)

—Nathaniel Scharping (@nathanielscharp), Science Writer

Citation: Scharping, N. (2025), Understanding cloud droplets could improve climate modeling, Eos, 106, https://doi.org/10.1029/2025EO250420. Published on 10 November 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.

The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.

According to Wikipedia, Pikillaqta is a large archaeological site located 20 km to the east of Cusco in Peru. Inhabited by the Wari people, it was abandoned at about 900 AD for reasons that have not been clear. At the point of abandonment, the site was incomplete, with several key buildings still being under construction. Thus, there has been considerable speculation as to why the site was left by the Wari people.

This area of Peru has a high level of seismic hazard. In the historical record, major earthquakes occurred in 1650, 1950 and 1986 in the immediate area. In a paper just published in the journal Geoarchaeology, Garcia et al. (2025), explore the hypothesis that the abandonment of Pikillaqta might be associated with earthquakes and a landslide at the site. Note that, although the paper is behind a paywall, the link should provide access for all.

The image below shows the site in 2017 – note the scarp to the northeast of the site:-

Google Earth image from 2017 showing Pikillaqta (note the different spelling on Google Earth), and the projected source of the debris flow.

A large part of Garcia et al. (2025) focuses on documenting so-called Earthquake Archaeological Effects at Pikillaqta – these are pieces of evidence in the archaeological record of past earthquake events. They have found 149 pieces of evidence, such as collapsed walls, and they infer from the orientations of these that they record the impacts of two large earthquakes (one between 856 and 988 CalAD and one between 770 and 900 CalAD) that have been identified from palaeoseismological studies of local faults.

But interestingly, Garcia et al. (2025) have also investigated a geological deposit, up to 3 m deep, in and around some of the buildings. This has the sedimentological characteristics of a debris flow, and it contains a fragment of an animal bone that has been dated to 766–898 cal AD. They have then used a high resolution digital elevation model to map the debris flow deposit. They have concluded that it initiated from the scarp to the northeast (see the label on the the Google Earth image) and then flowed through parts of Pikillaqta.

Radiocarbon dating is not precise, so this debris flow could have been triggered by an earthquake, or it could have been associated with exceptional rainfall (or a combination of the two, of course). But there is little doubt that the earthquakes and the landslide caused substantial damage to the site at about the time of abandonment, even when construction was ongoing.

The authors recognise that this is an unproven hypothesis, and encourage further research. But it is deeply fascinating to see how earthquakes and landslides may have shaped the events at this key archaeological site.

Reference

García, B., C. Benavente, M. Á. Rodriguez-Pascua, et al. 2025. Prehistoric Evidence of Crustal Earthquakes and Debris Flow in Archaeological Site of Pikillaqta in Cusco: Archaeological Implications. Geoarchaeology  40: 1-14. https://doi.org/10.1002/gea.70033.

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Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

A new medical study simulated an avalanche in the Italian Alps, demonstrating the life-saving power of a new portable fan system.

The Safeback SBX device weighs 18 ounces, fits into a backpack or vest, and draws oxygen from snowpack’s natural porosity to extend survival. While other safety tools—like emergency beacons and airbags—can make it easier to find someone in an avalanche, the Safeback SBX extends the time a person can survive while waiting for rescue.

“This is the biggest innovation in avalanche safety devices in 25 years.”

In a recent study in the Journal of the American Medical Association (JAMA), the Safeback SBX helped buried victims breathe under the snow for at least 35 minutes. That’s a critically important window. Roughly two thirds of people asphyxiate within 30 minutes of avalanche burial.

“This is the biggest innovation in avalanche safety devices in 25 years,” said Giacomo Strapazzon, an adjunct professor of emergency medicine at the Università degli Studi di Padova and lead author of the study.

Simulating an Avalanche

Strapazzon led the study for the Institute of Mountain Emergency Medicine at the private research center Eurac Research. While the makers of Safeback SBX proposed the study, the research team maintained independence.

To study the efficacy of the device, researchers first needed to bury willing victims. They put out a call for volunteers, screening potential participants for claustrophobia before bringing them to the mountains. They recruited 36 participants, ultimately using 12 men and 12 women, a gender balance celebrated in a separate JAMA editorial for addressing the “severe underrepresentation of females” in high-altitude physiology tests.

The test took place in a mountain pass, 2,000 meters above sea level in the Dolomite range in northeastern Italy. Participants were buried face down under 50 centimeters of high-density snow (500 kilograms per cubic meter) while wearing a Safeback SBX.

In an avalanche, the main cause of death is asphyxiation from lack of oxygen. But snow is naturally porous, up to 67% air even at a density of 300 kilograms per cubic meter. The Safeback SBX uses a large fan to suck oxygen-rich air from the snow behind a victim. It delivers up to 150 liters of air per minute toward the user’s face via shoulder strap tubes. The device works with the company’s backpacks and vests and can be activated before entering avalanche terrains. The equipment is cold weather tested, with a battery lasting at least 60 minutes even at −30°C.

During the test, half the participants received a functioning device that switched off after 35 minutes. The other half received a sham device. Participants were buried one at a time, while a gang of puffy-coat-clad medical professionals monitored their vital statistics from the surface.

The Safeback SBX successfully extended survival time. Of the 12 participants buried with a sham device, only one lasted 35 minutes. Seven had to be rescued after their pulse oximetry, or the level of oxygen in the blood, dipped below the study threshold of 80%. The other four requested an early rescue by radio. Average burial time was 6.4 minutes under the snow.

Of the 12 people buried with a functioning device, 11 lasted the full 35 minutes. Only one requested an early rescue. When the functioning devices were switched off after 35 minutes, participants lasted an average of 7.2 minutes. Five requested rescue, and six required it after their pulse oximetry dropped below 80%.

Winter Work

The device could be valuable for anyone who works and recreates in avalanche terrain, including Earth scientists.

Peter Veals is an atmospheric scientist at the University of Utah. His lab group deploys atmospheric gauges in the Wasatch Mountains each year before the snow falls. But winters are long, and equipment needs maintenance. His team may ski 30 minutes over 4.5 meters (15 feet) of snow to knock icicles off a heated radar dish before a storm starts.

His lab group uses a detailed safety plan, but it’s difficult to avoid avalanche terrain completely, he said. By extending the rescue time, the Safeback SBX has clear value in the mountains.

“Those are some brave volunteers.”

“There’s probably a lot of people that get there a minute too late,” Veals said of avalanche rescues. “Extending [survival time] by 20 minutes plus is a huge deal.”

Other factors affect survivability. People in an avalanche may strike a tree or boulder. Deeper, denser snow would delay a rescue. Preventive measures like avalanche training and education are still essential.

“All those factors mean this isn’t a silver bullet, but I think it is still a huge step forward,” Veals said of the device.

The study did a great job mimicking the conditions of an avalanche, he noted.

“I thought it was as applicable as you could get to the actual situation,” Veals said. “Those are some brave volunteers.”

—J. Besl (@jbesl.bsky.social), Science Writer

Citation: Besl, J. (2025), Safety device supplies life-saving air in an avalanche, Eos, 106, https://doi.org/10.1029/2025EO250418. Published on 7 November 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.

A landslide in coal waste covering about a square kilometre was triggered by heavy rainfall.

At about 4 am on 4 November 2025, a very large landslide occurred in a coal waste pile at the Mae Moh Mine in Thailand. This is an extremely large coal mining site that is co-located with electricity generating plants.

The landslide itself is very large. EGAT, the owner of the powerplant at the site, has released this image of the aftermath of the failure:-

The 4 November 2025 landslide at Mae Moh Mine in Thailand. Image released by EGAT.

It appears that the landslide occurred in Mae Moh 8 Project area, and that it damaged the offices of Sahakol Equipment Co. Ltd. Google Maps places both of these elements in the area of [18.34735, 99.70067], but the precise location of the landslide is unclear. We will need to wait for a cloud-free day to pin this down more precisely.

News reports indicate that movement was first detected on about 31 October 2025, and that heavy rainfall over the following days led to the failure. The main body of the landslide appears to be mainly translational, although there may be a rotational component in the head scarp area. Displacement near to the crown appears to be several tens of metres at least.

The lowest portions of the landslide have a flow type of mechanism. There may be some pipes on the slope on the right side of the image – it would be interesting to know if these have fed water into the slope.

Newspaper reports cover a statement to the Stock Exchange of Thailand by Sahakol Equipment Public Company Limited:-

“EGAT has declared a state of emergency in the area and has cordoned off the area for safety reasons, forcing the company to temporarily halt work on the Mae Moh 8 project. From a preliminary investigation, the company’s damaged assets include some office buildings and maintenance facilities, some of the Mae Moh 8 project’s soil conveyor belt structures, and other operating machinery.”

This is not the first such failure at Mae Moh mine. In a paper in the journal Engineering Geology, Hoy et al. (2024) describe a 1.2 km long waste dump failure on 18 March 2018. The landslide looks to have been remarkably similar to the event this week.

Reference

Hoy, M. et al. 2024. Investigation of a large-scale waste dump failure at the Mae Moh mine in Thailand. Engineering Geology, 329, 107400. https://doi.org/10.1016/j.enggeo.2023.107400

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

Marine heatwaves (MHWs)—prolonged periods of unusually warm ocean temperatures—are intensifying globally, disrupting marine ecosystems and biological processes. While their impacts on marine life are better documented, how MHWs influence precipitation has remained largely unexplored.

Zeng et al. [2025] investigate the relationship between MHWs and precipitation using two decades of high-resolution observational and reanalysis data (2002–2021). On average, MHWs shift global mean precipitation anomalies from −1.69 mm/day before peak intensity to +2.82 mm/day afterward. The study further identifies four distinct MHW types based on precipitation anomalies before and after the peak. The most common type (~46%) features reduced precipitation throughout its lifetime, followed by events (~26%) where precipitation transitions from negative to positive. In these latter cases, warmer early-stage oceans enhance evaporation and moisture convergence, increase moist static energy, and trigger stronger rainfall after the peak, which blocks solar radiation and accelerates MHW decay.

Understanding these dynamical processes is crucial for predicting future climate extremes in a warming world. This is among the first studies to identify precipitation–MHW relationships at different stages based on observations. These findings reveal dynamic air-sea feedbacks, showing that MHWs not only affect marine ecosystems but also modify regional precipitation patterns.

Citation: Zeng, S., Dong, L., Wu, L., Song, F., Zhang, Z., & Jing, Z. (2025). Distinct impacts of different marine heatwaves on precipitation. Journal of Geophysical Research: Atmospheres, 130, e2025JD044381. https://doi.org/10.1029/2025JD044381

—Yun Qian, Editor, JGR: Atmospheres

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Asteroids are primordial pieces of our solar system’s history, but they aren’t exactly pristine relics. Their surfaces in particular are eroded by solar radiation and pockmarked with meteorite impacts. Detailed studies of asteroids’ interiors are also lacking, simply because very few probes have been able to study them up close.

However, a promising new study uses data from the Gaia space observatory to understand the links between asteroid tumbling behavior, collision history, and interior structure. The key to the study is the discovery that rotation speeds of asteroids in the main belt, between Mars and Jupiter, don’t follow a random distribution.

When rotation period is plotted against asteroid size, asteroids fall into two distinct populations: slow spinners, which take more than about 24 hours to complete a rotation, and fast spinners, whose rotations take less than 24 hours. Small asteroids are more likely than large ones to be slow spinners.

“People found an excess [of] faster rotating asteroids and also an excess [of] slow rotating asteroids,” with fewer asteroids rotating at a medium speed, said Wen-Han Zhou, a planetary scientist at the University of Tokyo. In his Ph.D. research at the University of Nice, he and his collaborators realized that many of the slow rotators were also tumbling: rotating chaotically, rather than spinning steadily along a clearly defined axis.

“Asteroids are not islands in space; they collide with each other.”

“Asteroids are not islands in space; they collide with each other,” Zhou said. “When an asteroid spins very slowly, a tiny collision can make it tumble. This [also] tumbles the materials inside, which will dissipate the energy.”

This dissipation effect comes from internal friction. In their recent Nature Astronomy article, Zhou and his colleagues linked an asteroid’s rate of rotation, whether it is tumbling or spinning smoothly, its size, and its internal structure into a single theoretical framework. In this theory, fast rotating asteroids are stable spinners because any collision that sends them tumbling also jumbles their innards, causing internal friction that dissipates the chaos and brings the asteroids back to stability. Slow spinners, however, lock into tumbling chaotically because their guts don’t jumble enough to dissipate the energy.

“In my research, I propose slow rotators are all tumbling,” Zhou said. “This is a very strong statement, but so far it is consistent with observation.”

Zhou and collaborators also concluded that these slow tumblers are all rubble-pile asteroids: loose aggregates of small chunks barely held together by mutual gravitation, rather than being monolithic hunks of rock. This has implications for planetary defense.

“Imagine a bunch of pieces of Styrofoam stuck together with cohesive forces. You try to disrupt that, good luck!” said Alessondra Springmann, an asteroid researcher based in Colorado. Springmann has studied near-Earth asteroids using radar at the Arecibo Observatory in Puerto Rico but was not involved in this new research.

Knowing more “about an asteroid’s internal properties can help us if it ever came time to redirect an asteroid away from Earth.”

Scientists have tried. They found that smashing a projectile into a rubble pile, like NASA’s Double Asteroid Redirection Test (DART) mission did to the near-Earth asteroid Dimorphos, might not destroy it. The asteroid might simply re-form itself after being smashed. (Notably, Dimorphos is much smaller than the main belt asteroids in Gaia’s data.) Radar data on its rotation could tell planetary defenders what methods are useful well in advance. But so, too, could learning more about an asteroid’s innards.

Knowing more “about an asteroid’s internal properties can help us if it ever came time to redirect an asteroid away from Earth,” Springmann said.

You Spin Me Round

The European Space Agency’s Gaia observatory was built primarily to map the Milky Way. Because it provided a sensitive wide-angle view of the whole sky, the observatory also incidentally provided data on other objects, including asteroids in the main belt of our solar system. To determine asteroid spin rates, asteroid researchers turned to Gaia data showing how reflected light varies over time as the objects spin. This is when they found the clear division between fast and slow rotators.

Scientists have a reasonable explanation for the behavior of the fastest spinners: the YORP effect (for Yarkovsky-O’Keefe-Radzievskii-Paddack). In essence, asteroids receive sunlight across their surface facing the Sun, but their uneven surfaces absorb and reemit that light in more or less random directions. Over many millions of years, that accumulated difference in light exposure can cause asteroids to spin until they reach the spin barrier of one rotation every 2.2 hours, at which point they break into pieces if they’re rubble piles.

But slow rotators defied easy explanation.

However, Gaia provided another clue: If the variations in light it measured were regular, then the asteroid was a stable spinner. If they were irregular, then the asteroid was tumbling. Many slow spinners were tumbling, whereas almost every fast rotator was stable.

Zhou and his collaborators realized that if most or all slow spinners are tumblers, it could explain why observed asteroids are split into two distinct populations. Asteroids are too faint for even Gaia to clearly distinguish between rotators and tumblers in every case, but when the researchers simulated main belt asteroids on a computer—including the effects of collisions and YORP—they produced something strikingly similar to the Gaia data.

Along the way, the researchers also realized tumbling behaviors are linked to possible internal structural properties, particularly deformability and internal friction, which are not typically measurable without placing a seismometer on an asteroid’s surface. In other words, these analyses could actually reveal the life history and internal properties of asteroids in new ways.

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

Citation: Francis, M. R. (2025), What tumbling asteroids tell us about their innards, Eos, 106, https://doi.org/10.1029/2025EO250414. Published on 6 November 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
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Source: AGU Advances

This is an authorized translation of an Eos article. 本文是Eos文章的授权翻译。

众所周知，二氧化碳（CO2）浓度上升会导致地球大气温度升高。但缓慢的反馈过程，包括海洋的热量储存和碳循环的变化，意味着这种温度变化有时不会立即显现；地球可能需要数十年甚至数千年才能达到平衡。

然而，不同的气候模型对于何时达到这种平衡的预测却大相径庭。造成这些差异的原因之一是“模态效应”，即海面温度的不均匀变化会形成不同的海洋变暖模式，进而影响大气环流，最终影响云量、降水和热量传递。这些因素之间的复杂相互作用会加剧或减缓变暖，并影响气候对温室气体的敏感性。

帮助预测长期变暖模式的一种方法是回顾过去。挖掘古气候数据中的模式，特别是来自地球气候温暖时期的数据，可以为未来的变暖模式提供线索。刘小庆、张一歌等人分析了过去1000万年的海洋表面温度记录，以确定在二氧化碳浓度上升的情况下，不同海洋区域的相对升温情况。

该研究以地球上最大、最温暖的表层水体——西太平洋暖池为参考点，将其海表温度数据与其他17个海洋站点的海表温度数据进行比较，从而建立全球变暖模式。

随后，研究人员随后将这些古气候数据中显示的升温情况与几个模拟模型的结果进行比较，这些模型模拟了二氧化碳浓度相对于工业化前水平突然增加四倍的情况。他们发现，古气候数据和模型结果显示出相似的千年尺度升温模式，尤其是在高纬度地区。然而，当两者与过去160年的海表温度测量数据进行比较时，升温模式出现了显著的差异。受海洋热吸收的影响，现代升温仍处于过渡状态，而古气候模式则代表了完全的平衡响应。

研究人员指出，要达到新的平衡需要数千年的时间。该研究表明，与目前的瞬时气候变化相比，未来在中高纬度地区，包括北太平洋、北大西洋和南大洋的升温模式将更为显著。这种高纬度地区的升温幅度可能超过之前的估计，并且在千年尺度上的预测比在百年尺度上的预测更为明显。(AGU Advances, https://doi.org/10.1029/2025AV001719, 2025)

—科学撰稿人Rebecca Owen (@beccapox.bsky.social)

This translation was made by Wiley. 本文翻译由Wiley提供。

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When we look at the towering trees of old-growth forest patches in the Amazon, we might think these ancient beings have reached their maximum size and width.

It turns out they have not, a new study suggests. It shows that even the largest and oldest Amazonian trees still capture carbon dioxide (CO2)—and keep getting bigger, albeit at a slow pace.

Led by Adriane Esquivel-Muelbert, an ecologist at the University of Cambridge, the researchers analyzed 3 decades of tree measurements from 188 primary forest plots spread across nine Amazonian countries. Each plot was around 1 hectare, about the size of a city block, and was measured by teams using tapes and notebooks, often under harsh conditions.

The plots were selected from the Amazon Forest Inventory Network (RAINFOR), which has become one of the most important monitoring efforts in tropical ecology, according to Esquivel-Muelbert. The monitoring period varied between 1971 and 2015.

“We already knew the Amazon works as a carbon sink,” she said. “But we wanted to understand what’s happening inside the forest—what kinds of trees are changing, and how.”

The study, published in Nature Plants, found that the average tree size had increased by 3.3% per decade over the past 30 years. Large-canopy trees—those with trunks wider than 40 centimeters—grew even faster in diameter. Smaller trees shaded by larger ones also grew, while the size of medium-sized trees remained relatively stable.

The consistency across the Amazon basin suggests the increasing amount of CO2 in the atmosphere is the ingredient fattening up the trees. “Carbon is an extra resource,” Esquivel-Muelbert explained. “With the same amount of light, a plant can photosynthesize more efficiently when there’s more CO2 available.”

In other words, as humans release more carbon into the atmosphere, Amazonian trees seem to be using some of it to grow. The researchers interpreted the pattern as a mix of two effects: a winner-takes-all response, in which the tallest trees gain even more advantage, and a carbon-limited benefit response, in which smaller, shaded trees find it easier to survive in low light. Both effects can occur at the same time, leading to more biomass for both groups at the extremes of the size scale.

The study also found no sign that large trees are dying faster, contradicting earlier hypotheses that canopy giants would be the first casualties of heat and drought. The resilience of these ancient trees—some of them centuries old—is important because they sequester a disproportionate share of the forest’s carbon.

“The largest 1% of trees account for about half of all the carbon stored and absorbed by the forest,” Esquivel-Muelbert said. Losing them would mean losing much of the Amazon’s buffering power against climate change.

Not Exactly Good News

“It doesn’t mean carbon dioxide is good for the forest. What we’re seeing is resilience, not relief.”

The findings might sound like good news, but “it doesn’t mean carbon dioxide is good for the forest,” Esquivel-Muelbert said. “What we’re seeing is resilience, not relief.”

Carbon dioxide might be fattening up old trees, but its consequences for the global climate totally offset what might look like an advantage or a good thing at first sight, she emphasized.

To Tomás Domingues, a forest ecologist at the Universidade de São Paulo in Ribeirão Preto, the new results offer valuable real-world confirmation of what experimental models have long proposed. “The study shows that the community as a whole is gaining biomass, presumably due to higher CO2,” he said. “That aligns perfectly with what we’re testing at AmazonFACE.”

AmazonFACE—a large-scale open-air experiment near Manaus in the Brazilian state of Amazonas—exposes forest patches to elevated concentrations of atmospheric carbon to simulate future conditions. One of its main goals is to see how long the carbon fertilization effect can last before the forest runs into another limitation: the lack of nutrients such as phosphorus, calcium, magnesium, and potassium.

“The CO2 effect has a short life,” Domingues explained. “Trees can only turn extra carbon into growth if they have enough nutrients. In the Amazon, everybody—trees, microbes, fungi, insects—is competing for the same scarce resources.” If nutrients become limited, he added, growth could plateau or even reverse, regardless of the CO2 supply.

Still Holding On

The new findings highlight how complex the Amazon’s responses to human-driven change can be. While extra carbon has acted as a growth stimulus so far, climate stressors, especially heat, drought, and windstorms, are also intensifying.

Previous studies suggested that the Amazon’s overall carbon storage capacity is starting to weaken. Changes in species composition, repeated droughts, and the spread of degradation along the southern and eastern edges of the basin are already weakening parts of the system. “The forest is still resisting,” Esquivel-Muelbert said, “but that doesn’t mean it will resist forever.”

“These forests are resilient, but they’re irreplaceable. If we lose them, they don’t come back in our lifetime.”

Domingues noted that 30 years of observations, though impressive for tropical fieldwork, still capture only a short moment in ecological time. “For the forest, 30 years is nothing,” he said. “These trees live for centuries. We need to keep watching.”

Despite the unknowns, both researchers are clear: Protecting mature, intact forests is crucial if we want to fight climate change. Reforestation won’t replace the carbon storage capacity of old-growth trees. “These forests are resilient, but they’re irreplaceable,” Esquivel-Muelbert said. “If we lose them, they don’t come back in our lifetime.”

The study’s main message, Esquivel-Muelbert added, is not that the Amazon is thriving under climate change. It’s that the forest is still holding on, at least for now.

—Meghie Rodrigues (@meghier.bsky.social), Science Writer

Citation: Rodrigues, M. (2025), As CO2 levels rise, old Amazon trees are getting bigger, Eos, 106, https://doi.org/10.1029/2025EO250413. Published on 5 November 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
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The outlook for our planet’s water future is anything but reassuring. Across much of the world, communities are already confronting prolonged drought, shrinking reservoirs, and the growing struggle to secure reliable access.

“Even without global warming, if water demand continues to rise steadily, scarcity is inevitable.”

Now, a new study in Nature Communications suggests that so-called day zero droughts (DZDs)—moments when water levels in reservoirs fall so low that water may no longer reach homes—could become common as early as this decade and the 2030s.

To find out where and when DZDs are most likely to occur, scientists at the Center for Climate Physics in Busan, South Korea, ran a series of large-scale climate simulations. They considered the imbalance between decreasing natural supply (such as years of below-average rainfall and depleted river flows) and increasing human demand (including surging economic and demographic growth).

“Most studies tend to focus on supply alone, not on the interplay between supply and demand,” explained Christian L. E. Franzke, a climate scientist and coauthor of the study. “But even without global warming, if water demand continues to rise steadily, scarcity is inevitable.”

Cities on the Edge of Thirst

The team found that urban areas face the highest risk of DZDs. As cities expand, their thirst for water often exceeds what local systems can provide, leaving them exposed to shortages and instability.

The near catastrophe in Cape Town in 2018, when water was rationed to avoid a complete shutdown, remains a stark warning for cities worldwide. “I remember the measures that had to be taken,” Franzke said. “There were severe restrictions—people had to limit their use to just a few liters a day.”

Central spatial maps (a) and (b) show the spatial distribution of the ensemble mean waiting time and duration of day zero drought (DZD) events, respectively, following the time of first emergence (TOFE) at each grid point of DZD-prone regions across the globe. Map (c) represents the spatial distribution of the frequency (%) of extreme DZD events, defined as those where the event duration exceeds the waiting time, indicating prolonged water scarcity impact and short recovery period. The accompanying inset circular diagram illustrates the distribution of these events, with the color scale indicating the proportion (percentages) of grid cells experiencing such conditions. The surrounding paired panels depict the probability density function (PDF) of waiting time and duration for DZD events across seven DZD-prone regions. The vertical dashed lines mark the ensemble mean (black), 90th percentile (blue), and 99th percentile (green) for each region. The red dashed line represents the monthly scale of the compound extreme event, which is 48 months. The period considered for each grid point starts from the month after each decade of their respective TOFEs and continues until 2100. Click image for larger version. Credit: Ravinandrasana and Franzke, 2025, https://doi.org/10.1038/s41467-025-63784-6, CC BY-NC-ND 4.0

The human toll of DZDs goes beyond empty taps. It deepens existing inequalities, hitting low-income communities hardest because they are generally less able to endure rising costs of accessing clean water while also being more reliant on public utilities that are slower to secure alternate water sources. Urban DZDs also threaten public health by disrupting sanitation.

Overall, a DZD weakens economies and undermines social stability—especially in developing regions where physical, economic, and institutional vulnerabilities overlap.

According to the study, regions along the Mediterranean, southern Africa, and parts of North America are likely hot spots for DZDs, places where the zero point could arrive much sooner and last much longer.

“These already dry regions are becoming even drier,” said Alejandro Jaramillo Moreno, a hydroclimatology specialist from the Department of Atmospheric Sciences at Universidad Nacional Autónoma de México. Jaramillo was not involved in the new study. “Global warming is amplifying the contrast between wet and dry areas. Where rainfall is scarce, it will likely become scarcer.”

Avoiding the Tipping Point

For Franzke, solutions must come not only from individuals using water more responsibly but also from policymakers who prioritize smart management and modern infrastructure. “There’s a lot of leakage,” he said. “Pipes are old, and water escapes before it reaches people. Updating this infrastructure is crucial.”

It may seem unthinkable that metropolises like Los Angeles could one day face evacuation because of water shortages, but experts warn that this scenario isn’t far-fetched if systemic solutions aren’t implemented.

In many regions, water rationing caused by severe drought is already a reality. Chile, for instance, has experienced a water crisis for more than a decade, and water is rationed in areas including the nation’s capital and largest city, Santiago. Iraq, Syria, and Turkey are experiencing one of the worst regional droughts in their modern histories.

Jaramillo takes a long view of civilizations’ relationship with water supply. “Throughout history, cities have reached their zero point—not only in water but in other essential resources,” he reflected. “The difference is that now, we still have time (and knowledge) to change course.”

—Mariana Mastache-Maldonado (@deerenoir.bsky.social), Science Writer

Citation: Mastache-Maldonado, M. (2025), Are “day zero droughts” closer than we think? Here’s what we know, Eos, 106, https://doi.org/10.1029/2025EO250409. Published on 5 November 2025. Text © 2025. 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 that impacts science and scientists today.

Current emissions trajectories look set to warm the world by as much as 2.8°C (5.04°F) above preindustrial levels by 2100, according to a report released today by the United Nations Environment Programme (UNEP).

While some progress has been made on global emissions cuts, much more ambitious changes are necessary to avoid the worst of climate change’s effects.

The UNEP Emissions Gap Report is an annual stocktake of the gap between countries’ emissions reduction plans and actions needed to keep Earth’s temperature below the 1.5°C (2.7°F) warming limit set by the Paris Agreement, a legally binding international climate change treaty. Limiting warming to 1.5°C (2.7°F) will significantly reduce the losses, damages, and deaths from climate change, according to the UN.

“Years of grossly insufficient action from richer nations and continued climate deception and obstruction by fossil fuel interests are directly responsible for bringing us here.”

This year’s report found that though the predicted global temperature increase has fallen slightly since last year, and the emissions gap has narrowed, improvements were not nearly enough to avoid serious climate consequences. Additionally, the formal withdrawal of the United States from the Paris Agreement in January is expected to wipe out 0.1°C (0.18°F) of projected improvements. 

Even if every pledged country’s plans to reduce emissions (called Nationally Determined Contributions, or NDCs) are fully realized, the world is still projected to warm up to 2.5°C (4.5°F) by 2100.  

The “ambition and action” that was expected from countries’ updated climate pledges this year “did not materialize,” Inger Andersen, executive director of UNEP, wrote in the report.

The report’s findings are “alarming, enraging and heart-breaking,” said Rachel Cleetus, senior policy director for the Climate and Energy Program at the Union of Concerned Scientists, in a statement. “Years of grossly insufficient action from richer nations and continued climate deception and obstruction by fossil fuel interests are directly responsible for bringing us here.”

The report finds that the world is virtually certain to exceed 1.5°C (2.7°F) of warming by 2100 if current policies continue (data suggests it already has, temporarily), and that there’s just a 21% chance of staying below 1.5°C (2.7°F) if current NDCs and net-zero pledges are realized. Keeping average global warming under 1.5°C (2.7°F) remains technically possible, but requires an ambitious global emissions cut of 55% from 2019 emissions levels by 2035, according to the report.

 
Related

•  Read the Emissions Gap Report 2025: Off Target
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Current NDCs “have barely moved the needle,” the authors wrote.

The past year was another record-breaking year for the climate, with multiple annual reports on climate change finding concerning climate indicators reaching record-breaking levels. Ocean heat and wildfire-related tree cover loss are at all-time highs, deadly weather disasters have surged, and atmospheric warming is showing signs of acceleration. Global greenhouse gas emissions in 2024 were 2.3% higher than in 2023, more than four times higher than the annual average growth rate.

A Lack of Ambition 

The Emissions Gap Report, along with other climate change reports released in October, is expected to inform discussions at the annual UN Framework Convention on Climate Change Conference of the Parties (COP30), which will begin next week in Belém, Brazil. 

These annual conferences are notorious for falling short of global climate goals, and a challenging geopolitical environment could make ambitious action even less likely. Political will worldwide is lacking—fewer than one-third of parties to the Paris Agreement even submitted their required updates to their emissions reduction plans by this year’s September deadline. 

“This is where the new jobs are, this is where the economy goes…this is where the future lies.”

These new NDCs “have done little to increase ambition,” the report states. Some countries’ newly submitted NDCs are less ambitious than their current policies’ emissions projections.

Still, low-carbon technology, climate governance frameworks, and progress on climate legislation have advanced substantially, and “these developments position the international community far more favourably to accelerate climate ambition and action than a decade ago,” the authors wrote.

While such acceleration is urgent, it also “makes sense,” Andersen said in a press conference. “This is where the new jobs are, this is where the economy goes … this is where the future lies.”

Andersen called on leaders at COP30 to understand that it falls upon them to pick up the work of climate mitigation and deliver on Paris Agreement targets.

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

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A seemingly unending sheet of ice covers most of Antarctica, but there’s a hidden network of liquid lakes lying beneath. These subglacial lakes affect the flow of the Antarctic Ice Sheet, which in turn dictates how rapidly ice enters the ocean and contributes to global sea level rise.

Researchers recently discovered 85 previously unknown subglacial lakes in Antarctica in which water levels are changing. These results, which boost the number of active lakes tabulated under the White Continent by nearly 60%, were published in Nature Communications.

Way, Way Down

“The whole column of ice above the lake needs to go somewhere.”

Subglacial lakes exist at the interface between the bottom of the ice and the continent’s underlying bedrock. The average thickness of the Antarctic Ice Sheet is roughly 4,000 meters, so subglacial lakes in Antarctica are way down there, said Sally Wilson, lead author of the paper and a glaciologist at the University of Leeds in the United Kingdom. “These lakes are really deep.”

Their waters don’t freeze, thanks to gentle frictional heating from the movement of the Antarctic Ice Sheet and also from heat imparted from Earth’s interior.

Wilson and her colleagues recently used satellite data to look for signs of Antarctic subglacial lakes. The researchers mined archival data collected by CryoSat-2, a European Space Agency satellite launched in 2010 to measure changes in the thickness of polar ice sheets. The team looked for changes in the height of the ice surface caused by subglacial lakes either filling or draining. “When they fill, the ice surface above the lake moves up. The whole column of ice above the lake needs to go somewhere,” said Wilson. “It’s kind of like a blister under the ice sheet.”

A Census of Lake Activity

Wilson and her collaborators analyzed CryoSat-2 radar altimetry data collected from 2010 to 2020 over the margins of Antarctica. The vertical resolution of CryoSat-2 data is a few centimeters at best, and the team found 85 regions that changed in height not by centimeters but rather by meters. Those robust signals very likely correspond to active subglacial lakes, the team concluded.

A new study relying on archival CryoSat-2 data identified 85 lakes beneath the Antarctic Ice Sheet. Credit: ESA (Data source: Wilson, S. et al., 2025)/ESA

That makes sense, said Leigh Stearns, a glaciologist at the University of Pennsylvania in Philadelphia who was not involved in the research. “There’s really nothing else that could cause the kinds of elevation changes that they’re seeing.”

Wilson and her colleagues found that 50 of the lakes they discovered exhibited both filling and draining behavior. And 10 of those lakes exhibited a complete cycle of filling and draining. On average, it took several years for lakes to fill and also several years for them to drain, the team noted.

To their surprise, the researchers found that individual lakes didn’t always fill and drain to the same level. The ice above a lake known as Whillans_180 in West Antarctica, for instance, uplifted, then subsided, then uplifted again by roughly 5 meters. However, after this consistent pattern, the ice then subsided only by about half that amount before beginning to uplift yet again, Wilson and her colleagues found.

The team also noted five regions across Antarctica where the lakes they discovered appeared to be connected. The researchers inferred such a connection by observing upstream draining events in some lakes that were nearly contemporaneous with downstream filling events in other nearby lakes.

These observations hint at a complicated hydrological network beneath the Antarctic Ice Sheet, said Wilson. Tracing how water moves under ice has long been a holy grail of polar science, she said. “Identifying the lakes is one thing. But actually tracking the movement of water is an entirely different ball game.”

Have Lakes, Will Lubricate

Water flowing from subglacial lakes can have a significant effect on glaciers in the vicinity. “It can lubricate the bed of the glacier and potentially make it flow faster,” said Wilson. “That contributes to sea level rise.”

“Being able to look at something on the surface to infer what’s happening at the bed is really exciting.”

The freshwater present in subglacial lakes can also change local ocean currents when it eventually drains to the ocean. The mere presence of freshwater can furthermore affect the many marine organisms that live around an ice shelf, said Wilson.

Finding these new subglacial lakes offers a window of sorts into what’s happening deep beneath the Antarctic Ice Sheet, said Stearns. “Being able to look at something on the surface to infer what’s happening at the bed is really exciting.”

An unexpected trove of archival satellite data made this work possible, Wilson and her collaborators noted.

CryoSat-2 in particular has vastly over-delivered—its nominal mission was supposed to be only three and a half years; it’s still going strong, more than 15 years later. “It’s way outlasted its expected mission lifetime,” said Wilson. Such long-term records are particularly valuable because they can be used to trace gradual changes in polar regions, she said.

“We should be putting money and effort into keeping these datasets alive.”

—Katherine Kornei (@KatherineKornei), Science Writer

Citation: Kornei, K. (2025), Satellite data reveal changing lakes under Antarctic ice, Eos, 106, https://doi.org/10.1029/2025EO250412. Published on 4 November 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.

Source: Journal of Geophysical Research: Planets

Trapped in a gravitational push and pull between Jupiter and other Jovian moons, Io is constantly being stretched and compressed. Heat generated by these contortions has melted pockets of the moon’s interior so much that Io is our solar system’s most volcanically active body.

The James Webb Space Telescope (JWST) recently opened up new opportunities to get to know Io. Using data from its Near Infrared Spectrograph—which sees wavelengths corresponding to different compositions and temperatures—de Pater et al. have made new discoveries about Io’s volcanoes and atmosphere.

The researchers first looked at Io in November 2022 and found an extremely energetic volcanic eruption in the vicinity of the lava flow field Kanehekili Fluctus. These observations revealed, for the first time, that some volcanoes on Io emit an excited form of sulfur monoxide gas, confirming the team’s 2-decade-old hypothesis. JWST also detected an increase in thermal emissions at the massive lava lake in Loki Patera, generated by the lake’s thick, solid surface crust sinking into the molten lava beneath.

Nine months later, in August 2023, the researchers had another chance to peer at the same two regions on Io with JWST. Just as in 2022, Io was in Jupiter’s shadow, making it possible to capture emissions at wavelengths that might otherwise be obscured by sunlight.

The new images captured infrared thermal emissions from the same two regions. However, lava flows from the 2022 Kanehekili region’s eruption had spread to cover more than 4,300 square kilometers—about 4 times the area they covered in 2022. At Loki Patera, a new crust had formed and cooled, in keeping with the lake’s behavior over the past few decades.

The new images also captured sulfur monoxide emissions in Io’s atmosphere above Kanehekili Fluctus—as well as above two other regions without a clear volcanic association, which the researchers attribute to “stealth volcanism.” In another first, the 2023 images revealed sulfur gas emissions at wavelengths never before seen in Io’s atmosphere. Instead of being concentrated in patchy spots like the sulfur monoxide was, the sulfur gas was distributed more evenly across part of the northern hemisphere.

The data suggest that these sulfur emissions did not come from sulfur atoms spewed out of volcanoes but were mainly produced by electrons from Io’s plasma torus—an area around its orbit with high levels of charged particles—penetrating Io’s mostly sulfur dioxide atmosphere and thereby exciting sulfur atoms upon impact. The angle at which JWST observed Io, combined with the northern hemisphere’s location relative to the plasma torus, explained why the detected emissions were concentrated over the northern hemisphere. Alongside data from the Keck Observatory and the Hubble Space Telescope, the new findings suggest this plasma torus–atmosphere system remains quite stable over decades. (Journal of Geophysical Research: Planets, https://doi.org/10.1029/2024JE008850, 2025)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2025), Webb Telescope spies Io’s volcanic activity and sulfurous atmosphere, Eos, 106, https://doi.org/10.1029/2025EO250366. Published on 4 November 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: Space Weather

Space weather impacts caused by interplanetary disturbances of solar origin, such as coronal mass ejections, are coupled to Earth’s ionized upper atmosphere by electric currents travelling along magnetic field lines (field-aligned currents). These have historically been difficult to routinely measure with high spatial resolution of global coverage, with the best global monitoring to date from the AMPERE project, driven by IRIDIUM-Next telecommunications satellite data (drawn from six orbital planes).

In recent years, the number of satellites in low-Earth orbit has increased significantly; the OneWeb constellation has seen over 1,300 additional launches from 2019 to 2024. This recent mega-constellation uses 12 orbital planes, with a tighter distribution of satellites along each orbital plane.

By using the engineering data from these satellites, Archer et al. [2025] demonstrate that this data set can be used to derive global field-aligned currents at unprecedented resolution, showing that non-science grade instrumentation and commercial satellites have enormous potential scientific utility. The work performed here also highlights the challenges that need to be addressed with industry partners if the scientific community is to enable further advances with these platforms, and in turn provide datasets for space weather research and operations applications, helping protect critical infrastructure.

Citation: Archer, M. O., Evans, V., Eastwood, J. P., Camus, L.-A., Waters, C. L., Brown, P., & Armogathe, F. (2025). First detection of field-aligned currents using engineering magnetometers from the OneWeb mega-constellation. Space Weather, 23, e2025SW004573. https://doi.org/10.1029/2025SW004573

—Steven K. Morley, Editor, Space Weather

Text © 2025. The authors. CC BY-NC-ND 3.0
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It is reported that 51 people have been killed by a series of debris flows in Kenya, triggered by heavy rainfall.

On 31 October 2025, heavy rainfall triggered a series of large landslides in the vicinity of Chesongoch in Elgeyo Marakwet County, Kenya. To date, 26 people are known to have been killed and it is believed that a further 25 are missing, although continued heavy rainfall has led to a suspension of the rescue efforts.

Chesongoch is located at [1.12864, 35.64426]. Immediately to the west lies the Elgeyo Escarpment, a part of the Great Rift Valley.

This is a Planet satellite image of the area captured on the day of the landslides, but before the rainfall arrived:-

The site of the 31 October 2025 landslides at Chesongoch, in Elgeyo Marakwet county, Kenya. Image copyright Planet, used with permission, dated 31 October 2025.

And here is the same area on 3 November 2025, after the disaster:-

The aftermath of the 31 October 2025 landslides at Chesongoch, in Elgeyo Marakwet county, Kenya. Image copyright Planet, used with permission, dated 3 November 2025.

And here is a slider to allow comparison:-

Images copyright Planet.

Note that the post-disaster image is a composite of two images taken at different times on 3 November, which is why there is a cloud with an apparently strange linear edge in the centre of the image.

The post-event image shows a series of large channelised debris flows that have started on the Elgeyo Escarpment and travelled towards the east. The precise number is unclear (there are further examples to the north of the area covered by the image) because of the cloud, but there are at least five complexes in the area. These are likely to have started as shallow failures on the higher slopes, and there is considerable evidence of them eroding their channels. This is the area around Chesongoch itself, for example:-

The aftermath of the 31 October 2025 landslides at Chesongoch, in Elgeyo Marakwet county, Kenya. Image copyright Planet, used with permission, dated 3 November 2025.

Note that on the lower slopes, some of the debris flows have escaped from the channel to flow across the open hillslopes. It is likely that this accounts for some of the fatalities.

We will need to await better imagery to understand fully the initiation of these landslides, but this is a very cloudy area.

On Sunday, a further landslide hit the area, striking the town of Kipkenda [0.76202, 35.54115] to the south of Chesongoch. It is reported that two people were killed.

In April 2020, this area was affected by another series of debris flows, killing 15 people.

Reference

Planet Team 2024. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
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Wildfires in the rainy, humid Amazon might once have seemed unlikely, but the region is changing. In 2010 and 2015, the Amazon experienced record-breaking droughts and hot weather. Again in 2024, those records were smashed, in part by an extreme El Niño. A new study published in Biogeosciences reveals that the resulting fire season was the worst in 2 decades, pushing fires past deforestation as the Amazon’s biggest carbon emitter.

A Survey of Fire

Deforestation permanently converts forests to other land uses, most often for agriculture. Forest degradation, on the other hand, involves temporary damage to forested land. Degradation can be caused by forces such as droughts, fires, and smaller-scale logging operations and is less well documented than deforestation.

Since 1990, Clément Bourgoin and René Beuchle, both remote sensing researchers at the European Commission’s Joint Research Centre and authors of the new study, have been documenting forest degradation in the Amazon by tracking forest cover in satellite images. “We follow the fate of every single forest, whether it’s undisturbed or degraded,” Bourgoin said. In 2024, they kept up with reports of droughts and wildfires torching vast swaths of the Amazon. But they noticed that there weren’t available statistics on exactly how much forest had been affected.

“We tried to put numbers [to] the diffuse notion that something extraordinary has been happening in terms of forest fires.”

“We felt a clear lack of information that was there,” said Beuchle. “So we tried to put numbers [to] the diffuse notion that something extraordinary has been happening in terms of forest fires.”

The researchers’ tropical moist forest dataset classifies forest disturbances as either deforestation or degradation. They combined this dataset with the Global Wildfire Information System dataset, which uses thermal sensors on satellites to detect wildfires. By overlaying the two datasets, the researchers could align regions of large-scale forest degradation with those that had experienced forest fires.

A 2-Decade Record

The researchers expected to see forest degradation from fire, but Bourgoin said they were “quite surprised about the magnitude.” The analysis revealed that 3.3 million hectares of forest—approximately the same area as the state of Maryland—were affected by fires last year. Though deforestation in 2024 actually dropped by 20% compared to the average from 2019 to 2023, forest degradation, linked mainly to fires, increased by 400%. By area, forest degradation surpassed deforestation by more than 4 times in 2024, marking a shift in the threats to the Amazon’s health.

“We were unprepared for the sheer mass of burnt forest that we found in Bolivia. It was a shock.”

Brazil and Bolivia suffered the worst losses. In 2024, Bolivia lost 9% of all its intact forest to fire. “We were unprepared for the sheer mass of burnt forest that we found in Bolivia,” Beuchle said. “It was a shock.” Brazil saw the highest level of forest degradation on record.

The researchers estimate that the fires released 791 million tons of carbon dioxide into the atmosphere, a sevenfold increase from the average of the preceding 2 years. This amount of carbon dioxide marks an ominous transition: that of wildfire emissions surpassing deforestation emissions. The consequences also extend far beyond a single year, as burnt forests may continue to emit carbon for 7 years or longer after a fire.

“Everyone knew [2024] was going to break the records 6 months before” the El Niño even started, said Bernardo Flores, an ecologist at the Instituto Juruá and the University of Santiago de Compostela who wasn’t involved in the study. He said the study was important to quantify the extent of fire damage and show how strong El Niños will increase the burnt area. “That’s good science.”

“Fires are probably one of the main drivers of degradation that could lead to a tipping point.”

Flores also noted a warning in the new study’s data that will make fire prevention even more crucial. The degradation caused by burning makes the forest more susceptible to burning again in the future, so the huge regions of the Amazon that burned in 2024 could contribute to worsening fires in future drought years. This feedback cycle could make it harder for the Amazon forest to regenerate. “Fires are probably one of the main drivers of degradation that could lead to a tipping point,” after which the forest would no longer be able to regenerate and would become permanently degraded, Flores said.

Public and governmental awareness of the magnitude of the wildfires is an especially important step in avoiding the tipping point in the Amazon, where nearly all fires are human caused—either for agricultural purposes or to facilitate illegal deforestation. Next, the researchers plan to track how past disturbances may influence future degradation and to study how well the regions that burned in 2024 recover over time. Still, for now, they are making their data publicly available to help guide fire-safe policies in the area in the hopes of preventing irreversible damage to the Amazon. “It helps to put degradation on the agenda,” Bourgoin said.

—Andrew Chapman (@andrewchapman.bsky.social), Science Writer

Citation: Chapman, A. (2025), Fire, not deforestation, is now the Amazon’s biggest carbon emitter, Eos, 106, https://doi.org/10.1029/2025EO250411. Published on 3 November 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.

Marine heat waves describe instances of extraordinarily warm waters that can linger at the surface of the ocean for months. Much like the heat waves we experience on land, marine heat waves can alter environmental chemistry and disrupt biological processes. While catastrophic losses of megafauna are hard-to-miss indicators of a system in distress, researchers are now starting to amass enough data to understand how microbial organisms at the base of the ocean’s food webs are also responding to heat waves.

A new study published in Nature Communications presents a decade of measurements documenting two successive heat waves in the northeastern Pacific Ocean. The paper’s interdisciplinary team of authors used a combination of an autonomous robotic float, a research cruise, and satellite data to understand how microbial communities in the region reorganized in response to the extreme events.

The researchers discovered that production of organic matter increased at the ocean surface during the heat waves, but the carbon-rich particles didn’t sink or swim—rather, they just stayed in place.

The Biological Carbon Pump

Phytoplankton—tiny photosynthesizing microbes—prime the biological carbon pump. By using sunlight and carbon dioxide (CO2) to grow, they draw carbon out of the atmosphere and into the ocean’s carbon cycle. Zooplankton graze on the vast fields of these plantlike organisms, transporting carbon deeper into the water column in the form of fecal pellets and chunks of half-eaten plankton. Eventually, some of these particles sink deep enough to feed ecosystems of the deep ocean.

“The capacity for the ocean to sequester carbon relies on microbes at the base of the food web.”

This carbon pump represents a globally relevant buffer against the impacts of climate change, as the ocean absorbs approximately a quarter of CO2 emitted by human activity. Some estimates suggest that our current atmospheric concentration of CO2 could increase by as much as 50% if the biological carbon pump stopped shuttling carbon to the depths of the ocean.

“The capacity for the ocean to sequester carbon relies on microbes at the base of the food web, so it’s very important that we start understanding what these impacts from marine heat waves are on the microbial communities,” explained Mariana Bif, lead author of the new study. Bif is an assistant professor at the University of Miami and was previously a researcher with the Monterey Bay Aquarium Research Institute (MBARI).

When the Food Web Gets Tangled

In both of the marine heat waves tracked in the study, researchers found that the biological carbon pump showed signs of overheating. Carbon-rich particles loitered at approximately 200 meters (660 feet) below the surface, but during the two heat waves, different mechanisms caused the pileup.

The first heat wave included in the study began in 2013, when unusually weak winds over the Pacific failed to blow the warm air of summer back to the mainland of the United States. The heat wave, dubbed “the Blob,” made headlines as warm, stagnant, oxygen-deficient waters resulted in massive die-offs of fauna from all corners of the Pacific before dissipating in 2015.

In 2019, patchy cloud cover over the ocean and a shallower mixed layer at the sea surface set the stage for another heat wave to sweep the northeastern Pacific. This second heat wave brought temperatures right back up and became known as “the Blob 2.0.”

Bif and her coauthors found that during both heat waves, the marine microbial community went through a change in its “middle managers.”

Within the initial Blob years, physical and chemical conditions favored smaller phytoplankton species, which in turn favored a new herd of zooplankton grazers. This discrete food web eventually created an ocean layer full of organic particles that were too light to sink into the denser waters of the deep.

During the Blob 2.0, concentrations of particulate organic matter were even higher, but the increase wasn’t all from primary production. This time, conditions favored thrifty species. Organisms that could opportunistically feast on detritus and lower-quality organic matter became more prevalent, showing that the system was cycling and recycling carbon to keep it at the top of the water column. Within this community, parasites thrived, and organisms (including a group of radiolarians) that had never previously been seen in the northeastern Pacific started becoming regulars.

Measuring in the Middle of Nowhere

The array of technology used in the study distinguishes it from previous efforts to catalog the effects of marine heat waves.

“We’re now moving into an era of ‘big data’ in ocean biogeochemistry, whereas before we were just restricted to what we could collect from ships.”

“We’re now moving into an era of ‘big data’ in ocean biogeochemistry, whereas before we were just restricted to what we could collect from ships,” said Stephanie Henson, a principal scientist at the National Oceanography Centre in Southampton, U.K. Henson was not involved in the study.

Henson explained that autonomous floats and other advanced monitoring systems are allowing researchers to work with datasets that span beyond the length of a research cruise.

“People have been studying marine heat wave responses in systems like coral reefs and so on,” Henson said, explaining that researchers have observed that not every biological response is the same from one marine heat wave to the next. However, she noted that this study was the first she’s seen that demonstrates that ocean carbon fluxes are also having complex responses to marine heat waves.

To check the vital signs of the Pacific before, during, and after each of the heat waves, the researchers tapped into the Global Ocean Biogeochemistry Array (GO-BGC). GO-BGC instruments are a subset of the Argo array, a global network of thousands of autonomous robotic floats. Each float drifts freely in ocean currents, keeping tabs on pH, salinity, temperature, and more.

Mariana Bif gets ready to deploy a GO-BGC float in the Bay of Bengal. The float will drift freely in ocean currents at approximately 1,000 to 2,000 meters deep, returning to the surface every 10 days to send data about ocean temperature, salinity, and chemistry via satellite to researchers back on shore. (The Indian Ocean was not part of the new study, but Bif used GO-BGC floats in the Pacific to conduct the research.) Credit: Sudheesh Keloth, July 2025

Despite all that they can do, the floats are not able to collect microbial samples. For this, instead of Bif seeking the data, the data came to Bif.

Steven Hallam, a microbiologist at the University of British Columbia and a coauthor on the new study, reached out to Bif after reading an interview with her about her work on marine heat waves. He had a hunch that the planktonic DNA samples stored in his lab’s freezer might be helpful for Bif’s investigation into the ocean’s carbon cycle. Scientists in Hallam’s lab group had previously published research about bacterial communities in the same region, using samples collected during research cruises along the Line P transect off the coast of British Columbia.

After some back-and-forth via email, Hallam’s lab group reran the samples, expanding the analysis from bacteria to the entire community composition, resulting in a significant contribution to Bif’s study.

While the story of how the planktonic DNA came to Bif is a testament to the power of science communication and collaboration, Henson noted that the Line P transects “don’t necessarily overlap spatially with the regions of greatest impact of the marine heat waves” and combining datasets of different scales (such as shipboard data and the autonomous float datasets) should be done cautiously.

Still, Henson added, “it’s the best we can do, at the moment.”

Lingering Uncertainties

As for future research, Bif is involved in a few new projects exploring marine deoxygenated regions but said, “My focus is always the BGC-Argo floats.”

Bif noted that it will be interesting to look at BGC-Argo data from the floats that are in the middle of the marine heat wave currently affecting the North Pacific. That heat wave is already showing signs of slowing down, though scientists say it will likely hang around through the winter.

“I’m not sure if this one is going to have the legs that some of these previous marine heat waves in the region had,” said Nick Bond, who was not involved in this research but studied marine heat waves as part of his previous role as the Washington state climatologist. He is now a senior research scientist at the University of Washington.

“What we don’t measure, we can’t understand. We need more investments into monitoring the ocean.”

Bond added that while there’s “tentative evidence” that climate warming may be increasing the frequency of marine heat waves in the Pacific, there’s still much more to learn before scientists can accurately forecast how they will behave in the future.

Meanwhile, another looming unknown for this field of research is developing back onshore.

“There is a bit of a concern in the community because at the moment, for the global Argo program, the U.S. contributes about half of the floats that are deployed,” said Henson, her concern alluding to recent budget cuts to nearly all areas of federally funded research in the United States. However, she explained that other countries are stepping up with contributions to keep the Argo program afloat.

“What we don’t measure, we can’t understand. We need more investments into monitoring the ocean,” said Bif.

—Mack Baysinger (@mack-baysinger.bsky.social), Science Writer

Citation: Baysinger, M. (2025), Marine heat waves slow the ocean’s carbon flow, Eos, 106, https://doi.org/10.1029/2025EO250410. Published on 3 November 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.