EOS

Source: AGU Advances

Earth’s largest mass extinction occurred around 252 million years ago, wiping out the majority of marine and terrestrial life, disrupting the global carbon cycle for several hundred thousand years, and earning the title “the Great Dying.” Global warming, changing temperature gradients, shifts in nutrient cycling, and oxygen depletion wiped out 81% of all marine life at the time.

But cooler, relatively high latitude marine environments may have been refuges for species escaping volatile climate conditions elsewhere. Buchwald et al. examined rock samples from the Arctic archipelago of Svalbard, Norway, and identified high levels of lipid biomarkers in rocks dated soon after the Permian-Triassic extinction. Though the exact organism producing these molecules is unknown, it is likely a group of phytoplankton. This finding suggests that the cooler waters of the paleo-ocean allowed this primary producer to bloom and sustain remaining sea life.

The researchers collected 32 rock samples from Svalbard taken from layers formed pre- and postextinction and compared them with samples taken from other locations, such as northern Italy, southern China, and Türkiye. All represent warmer regions surrounding the prehistoric Tethys Ocean, a precursor to the modern Indian Ocean and Mediterranean Sea. The team examined the samples for C33–n-alkylcyclohexane (C33–n-ACH) and phytanyl toluene, molecular fossils that act like fingerprints of ancient marine life.

In the Svalbard samples dated after the Permian-Triassic extinction event, C33–n-ACH levels were 10 times higher than in samples from before the event. The researchers note that the preextinction samples likely experienced more degradation, but that alkylcyclohexane biomarkers are relatively resistant to such degradation, meaning the higher amounts detected after the extinction point to a true increase in the biomarker. In the samples taken from warmer regions, far less C33–n-ACH overall was detected, but a similar increase in abundance after the extinction event occurred.

Phytanyl toluene was largely absent from the Svalbard samples before the extinction and showed a similarly dramatic increase in the extinction’s aftermath. It was not present in the tropical samples, suggesting that it was produced by a different phytoplankton than the species that produced the C33–n-ACH.

Overall, these findings suggest that the phytoplankton producers of these biomarkers remained stable and thrived in cooler waters during a time when warmer waters were unable to support significant marine life, the researchers say. (AGU Advances, https://doi.org/10.1029/2025AV001785, 2025)

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

Citation: Owen, R. (2025), How algae helped some life outlast extinction, Eos, 106, https://doi.org/10.1029/2025EO250426. Published on 13 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.

Where Science Connects Us

This month, Eos is meeting the moment “Where Science Connects Us” with deep dives into the state of the geoscience profession (“Eight Ways to Encourage Equality, Diversity, and Inclusion Discussions at Conferences”) and some ATLAS-sized enthusiasm for a comet (“How an Interstellar Interloper Spurred Astronomers into Action”), as well as research updates (“Tracing Black Carbon’s Journey to the Ocean”) and quirky queries (whither Planet Y.)

AGU’s annual meeting is in New Orleans this year, and our feature story, a forward-looking analysis of the ways hurricane forecasting has grown in breadth and depth since Hurricane Katrina, is a great read for those attending AGU25. It’s a great read for those who aren’t at the meeting, too—a reminder of the relevance and importance of Earth and space sciences for discovery and solution-based inquiry.

So follow the path of the Mighty Mississippi as you let Eos show where science connects us to Earth, space, and each other.

—Caryl-Sue Micalizio, Editor in Chief

Citation: Micalizio, C.-S. (2025), Where science connects us, Eos, 106, https://doi.org/10.1029/2025EO250423. Published on 13 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’ Vox is a blog from AGU’s Publications Department.

AGU Publications is pleased to announce five new Editors-in-Chief (EiCs) to join our journals program in 2026. Each of them were appointed to continue the great work done by their predecessors.

We thank the following outgoing EiCs for their leadership and contributions during their terms:

• JGR: Space Physics: Michael Balikhin (deceased, 26 October 2025), University of Sheffield, UK, EiC 2020-2025,
• Paleoceanography and Paleoclimatology: Matthew Huber, Purdue University, United States, EiC 2020-2025,
• Perspectives of Earth and Space Scientists: Michael Wysession, Washington University in St Louis, United States, EiC 2019-2025,
• Space Weather: Noé Lugaz, University of New Hampshire, United States, EiC 2019-2025,
• Tectonics: Taylor Schildgen, GFZ German Research Centre for Geosciences, Germany, EiC 2020-2025.

And a warm welcome to their successors:

JGR: Space Physics

Natalia Ganjushkina  
University of Michigan, USA and Finnish Meteorological Institute, Finland  

Note: Natalia’s full term will begin on January 1, 2026. Following the sad news of Michael Balikhin’s passing, Natalia has graciously agreed to serve as Interim Editor-in-Chief for the remainder of 2025, ensuring a smooth transition and continued leadership for the journal.

Paleoceanography and Paleoclimatology

Sarah Feakins

University of Southern California, USA

Perspectives of Earth and Space Scientists

Annalisa Bracco 

Euro-Mediterranean Center on Climate Change (CMCC), Italy

Space Weather

Steven Morley 

Los Alamos National Laboratory, USA

Tectonics

Giulio Viola 

Università di Bologna, Italy

AGU journals’ Editor-in-Chief searches are conducted through an open call and managed by dedicated Search Committees. The composition of each committee follows a defined process and coordination between the Publications staff team and the Publications Committee. Search Committees make their recommendations to the Publications Committee, which ensures diversity and balance across all searches conducted during the year. The Publications Committee then forwards its final recommendations for a reputation review performed by leaders of the Board, Council, Leadership Development/Governance Committee, and staff partners. We extend our sincere thanks to all these colleagues for their invaluable contributions to this important process.

Citation: AGU Publications (2025), Announcing new AGU journal editors-in-chief starting in 2026, Eos, 106, https://doi.org/10.1029/2025EO255034. Published on 12 November 2025. This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

What better way to study an entire planet’s monthly exchange of CO2 between the atmosphere, oceans, and land than to position a satellite in space that measures these swings in the atmosphere’s CO2 on a daily basis? We’ve had that tool, NASA’s Orbiting Carbon Observatory-2 (OCO-2), since 2014, and it has yielded an impressive body of science, demonstrating the impacts of natural and human-induced changes in emissions and sinks of CO2, including large-scale fires, ocean warming, and the economic shutdown during the COVID-19 pandemic.

The monthly growth rate of global atmospheric CO2 (ppm yr-1) measured by the OCO 2 satellite‐ (black line) demonstrates a relationship with the Earth’s global surface temperature increase (relative to the preindustrial baseline; red dashed line). The fossil CO2 emissions (black dashed line) are interpolated annual values (also expressed as ppm yr-1), which dipped during the pandemic of 2020, but have resumed growing since then. Credit: Pandey [2025], Figure 1a

In addition to unprecedented frequency of global CO2 measurements, it also provides spatial resolution that enables attribution to changes of sources and sinks across latitudes and continents. This science is driven, in part, by concerns about climate change, but even if we take climate out of the equation to remove political implications, the basic science of understanding the Earth’s carbon cycle has advanced tremendously by this extraordinary tool in space.

Pandey [2025] likens the possible premature decommissioning of this satellite to removing stethoscopes from medical doctors’ toolkits, and yet that is precisely what the current U.S. Administration’s proposed 2026 budget would do. This commentary elegantly describes what has been learned from the OCO-2 mission and how it can inform policy; it should be mandatory reading for anyone, from members of Congress to their constituents, who could possibly influence funding for the OCO-2 mission.

Citation: Pandey, S. (2025). Taking Earth’s carbon pulse from space. AGU Advances, 6, e2025AV002085. https://doi.org/10.1029/2025AV002085

—Eric Davidson, Editor, AGU Advances

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.

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.

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 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

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.

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

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.

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

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。

Read this article on WeChat. 在微信上阅读本文。

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.

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

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

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
•  U.N. Sees Slight Progress on Climate Action, Partly Offset by the U.S.
•  Union of Concerned Scientists: UN Report Confirms Planetary Warming Will Breach 1.5 Degrees Celsius, Richer Nations Primarily to Blame
•  1.5°C: What It Means and Why It Matters
•  Get Involved: AGU Science Policy Action Center
 

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

These updates are made possible through information from the scientific community. Do you have a story about science or scientists? Send us a tip at eos@agu.org. 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.

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.