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Over the past week we've witnessed the many political discussions that go with the territory of a COP—or, more verbosely, the Conference of the Parties to the United Nations Framework Convention on Climate Change.

Magnetic data collected in the late 1960s has been brought back to life by a research team including a Keele scientist, who have used it to learn more about how the continent of Africa is stretching and splitting apart.

The world is warming, yet summer temperatures on the southern slope of Mount Everest, measured continuously by the Pyramid Laboratory since 1994, have dropped over the past 15 years.

The reason? Cold downslope winds, caused by the increased temperature differences between the warmer air above the glacier and the air mass in direct contact with the glacier’s frozen surface.

These katabatic winds create a cooling effect around mountain glaciers, explained Thomas Shaw, a glaciologist at the Institute of Science and Technology Austria. “They’re melting more slowly than they would if there was a one-to-one correspondence between atmospheric temperature and the temperature of the glacier boundary layer.”

Scientists have made note of this phenomenon since the late 1990s, but studies have so far been limited to specific glaciers.

To understand the phenomenon’s extent and the factors influencing it on a global scale, Shaw and his colleagues collected and analyzed a dataset from 62 glaciers across 169 glacier campaigns, amounting to an unprecedented 3.7 million hours of air temperature data.

While much of the data were easily accessible, some were “almost the equivalent of being written on the back of a napkin,” said Shaw, who was able to include previously unpublished data from other researchers. “It takes a lot of emailing, clicking, finding, searching, and thinking, ‘Oh, I remember there was someone that published something on this.’”

Changing Projections

The study, published in Nature Climate Change, found that the glacier boundary layer warms an average of 0.83°C for every degree of ambient warming.

“This is not the only process affecting glacier melt, but it’s an important one that we didn’t have proof of before,” said Inés Dussaillant, a glaciologist at Centro de Investigación en Ecosistemas de la Patagonia in Chile who was not involved in the study.

“It may change our projections…and IPCC reports for the future evolution of glaciers or sea level contribution.”

Currently, this effect is not taken into account when modeling how glaciers will change over time, said Harry Zekollari, a glaciologist at Vrije Universiteit Brussel in Belgium who was not involved with the study. “It may change our projections and how we make them, and it may change projections and [Intergovernmental Panel on Climate Change] reports for the future evolution of glaciers or sea level contribution.”

According to Shaw’s analysis, the main factors driving the cooling effect are the temperature difference between the glacier boundary layer and the surrounding air, the size of the glacier, and humidity. Debris cover on the glacier and strong synoptic winds hinder the effect.

This phenomenon means that rising ambient temperatures actually increase the cooling effect on large glaciers—but only up to a point. “Glaciers are not protected because of this; they’re not cooling. It’s a bit of a misnomer,” said Shaw. While they are melting more slowly than would be expected with linear warming, the effect is still substantial. The study projects that globally, these near-surface cooling effects will peak during the late 2030s as temperatures rise.

As glaciers shrink in size, they will no longer be able to generate katabatic winds, and their rate of warming will begin to reflect ambient temperatures. According to the study, this will lead to accelerated melting from mid-century onward.

Going, Going, Gone

Shaw and his coauthors noted large regional variations in the data. While the cooling effect is not expected to peak until the 2090s for glaciers in New Zealand and the southern Andes, glaciers in central Europe have likely already passed this mark and are deteriorating at an increasing pace.

The study’s results tally with other findings. Earlier this year, a study of global glacier mass changes found that central Europe lost 39% of its ice mass between 2000 and 2023, faring the worst of all 19 regions studied.

A prime example is Pasterze, an Austrian glacier where research into the cooling phenomenon first started in the 1990s. “This was once a much larger glacier, with a much stronger observed katabatic cooling effect. Now it’s disintegrating very fast,” said Shaw, noting it will likely not be Austria’s largest glacier for much longer. “It’s already showing evidence of how rapidly glaciers can react to climate when they begin to disappear.”

But while troves of reliable long-term data are available for areas like the European Alps, Iceland, Svalbard, and western North America, glacier monitoring is not equally distributed worldwide. Dussaillant would like to see more support for regions where governments are not able to maintain ongoing glacier monitoring. “We cannot really say that this is the global picture, when in fact, some regions still have huge gaps which we need to fill and better understand.”

With around 200,000 glaciers worldwide, there is, indeed, still a lot of work to be done before a truly global picture emerges, said Zekollari. “But it’s a massive step forward compared to what we had.”

—Kaja Šeruga, Science Writer

Citation: Šeruga, K. (2025), Glaciers are warming more slowly than expected, but not for long, Eos, 106, https://doi.org/10.1029/2025EO250430. Published on 20 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.

Thin layers of sedimentary rock in Mars’s Gale Crater suggest that the planet once had a moon much larger than the two that orbit it today, according to work to be presented at AGU’s Annual Meeting 2025 on 17 December. Unlike the current Martian moons Phobos and Deimos, the gravitational pull of the hypothesized moon would have been strong enough to create tides in bodies of water on or below the planet’s surface.

The team analyzed images from cameras on the Curiosity rover, which has been trundling across Gale Crater since 2012. The Mars Hand Lens Imager, for instance, captures images with resolutions up to 13.9 micrometers per pixel.

Pictures of a rocky outcrop snapped during four Martian days in late 2017 and early 2018 revealed a section of fine, repeating layers in alternating light and dark colors. The researchers interpret those layers as tidal rhythmites, or sediments deposited by the regular back-and-forth sloshing of the tides.

“Our study provides sedimentary evidence for the case of tidally deposited rhythmites, hinting at a past larger moon for Mars.”

“Our study provides sedimentary evidence for the case of tidally deposited rhythmites, hinting at a past larger moon for Mars,” Ranjan Sarkar, a planetary scientist at the Max Planck Institute for Solar System Research in Gottingen, Germany, told Eos via email. “This, in turn, aligns with the hypothesis that Mars has repeatedly had larger moons that were tidally destroyed into rings, which then reformed into successively smaller moons.” That is, the larger moon or moons would have been pulled apart by the force of Martian gravity, which would have exerted a stronger pull on the planet-facing side of the moon than the opposite side.

The layering was detected at Vera Rubin Ridge on the flank of Mount Sharp, a sedimentary peak in the middle of Gale Crater. The studied area was about 35 centimeters long and 20 centimeters thick. Individual bands in the rock ranged from submillimeters to millimeters thick, with wider, light-toned bands and darker, thinner bands.

This graphic, for presentation at AGU’s Annual Meeting 2025, traces Curiosity’s path to the Jura outcrop on Vera Rubin Ridge. Color-enhanced images from the rover show the layered rocks interpreted as evidence of tidal rhythmites, with similar layers in an Earth setting shown for comparison. Click image for larger version. Credit: Ranjan Sarkar, Priyabrata Das, Suniti Karunatillake

Comparison with other observations along the ridge suggests the layers were deposited roughly 3.8 billion years ago, when Gale Crater contained a lake.

“Back-of-the-Envelope” Profile

Not all rhythmites are tidal: Similar sedimentary layers can be deposited by winds, seasonal variations in precipitation or glacier melts, or other processes, the researchers note.

“The finely laminated rhythmites in this crater are most likely varves, or deposits that reflect seasonal changes in the climate,” said Bob Craddock, a geologist at the National Air and Space Museum who was not involved in the study. More water flows into a lake during the warmer summer months, producing thicker sediment layers with larger grains compared to those laid during winter, he said. “As this continues through time, you get rhythmites.”

“It’s very tricky. We can’t be decisive, so our argument is one of consistency.”

Sarkar, however, said the structure of these layers doesn’t match what would be expected of seasonal deposits. “Annual varves usually show simple light-dark couplets, but we observe alternating thick-thin bands showing paired dark laminae,” he said. Such patterns “are commonly used as markers of tidal sedimentary signatures on Earth.”

“It’s very tricky,” said team member Suniti Karunatillake, a geologist and geophysicist at Louisiana State University. “We can’t be decisive, so our argument is one of consistency.…We felt that the observations are generally more consistent with a tidal setting.”

The layers probably were deposited with a “monthly” cycle of about 30 days, Karunatillake said. Even if Phobos or Deimos were much closer to Mars than they are today, neither is massive enough to create such a tidal cycle. Instead, combining this new work with modeling by previous researchers, the team estimated the tides were raised by a body at least 18 times the mass of Phobos, the larger moon, orbiting at an altitude of about 3 times the radius of Mars.

Phobos, photographed by the Mars Reconnaissance Orbiter, is not massive enough to have raised tides on Mars. It could be a remnant of a larger moon that was destroyed in a giant impact. Credit: NASA/JPL-Caltech/University of Arizona

“That’s our back-of-the-envelope calculation,” Karunatillake said. “Anything smaller and it would be difficult to induce this type of tidal activity, especially when you consider that Gale Crater is quite small as a water body on the planetary scale.”

The possibility of a smaller moon causing the observed tidal activity might be more realistic, Karunatillake added, if there were a connection between Gale Crater and the northern ocean, but no connection has yet been seen. However, even a subterranean link, such as the network of flooded caves and tunnels beneath Earth’s Yucatán Peninsula that leads to the Caribbean Sea, would suffice. “There are instances where you get tidal variations inland, as long as there’s a subsurface connection with the ocean,” he said.

Pondering the Martian Moons

Planetary scientists have pondered the origins of Phobos and Deimos extensively in recent decades. The original theory said they were captured asteroids, but it’s not easy for a planet to nab even one asteroid, much less two.

Some studies have suggested that Mars originally had a larger moon—either a captured asteroid or one that formed from an early giant impact. That body then could have been pulverized by the gravity of Mars or by its own collision, forming a ring that then gave birth to smaller moons. In fact, such a scenario could have played out multiple times. “Our study provides actual (ground) evidence, from measured laminae periodicities, for the predicted/hypothesized past larger moon,” Sarkar said.

The researchers are considering conducting a detailed celestial mechanics study to refine their estimates of the mass, distance, and orbital period of the proposed moon. They’re also examining two other sites in Gale Crater that appear to show similar tidal rhythms.

Any inconsistencies among the sites would “dispute our model, and possibly falsify it,” Karunatillake said. “But any agreement would take us toward a stronger argument for an ancient large moon.”

—Damond Benningfield, Science Writer

Citation: Benningfield, D. (2025), Sediments hint at large ancient Martian moon, Eos, 106, https://doi.org/10.1029/2025EO250434. Published on 20 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.

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

How do the deep forces of the Earth’s interior shape surface faults, fractures and rivers? The results of a new global analysis show that rivers, faults, and stresses often align, but the degree of correspondence depends on fault type, stress source, and river size.

Kuhasubpasin et al. [2025] present a new framework to quantify the relative roles of lithospheric structures and mantle dynamics, offering fresh insights into how deep Earth processes govern the surface. A novel procedure is proposed to assess the relative role of mantle flow and lithospheric differences to the surface features, which may help constrain the individual forces acting to deform the lithosphere, creating topography. This holistic perspective on the coupled evolution of Earth’s interior and its surface shows how the interior of the Earth affects and perhaps even controls the surface.

Citation: Kuhasubpasin, B., Moon, S., & Lithgow-Bertelloni, C. (2025). Unraveling the connection between subsurface stress and geomorphic features. Geophysical Research Letters, 52, e2025GL116798. https://doi.org/10.1029/2025GL116798

—Fabio A. Capitanio, Editor, Geophysical Research Letters

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 tectonic plates under Africa and Asia are slowly drifting apart, as the Gulf of Suez that separates these two land masses continues to widen at a rate of about 0.26–0.55 millimeters per year.

If heat-trapping pollution from burning coal, oil and gas continues unchecked, thousands of hazardous sites across the United States risk being flooded from sea level rise by the turn of the century, posing serious health risks to nearby communities, according to a new study.

Planet imagery shows the massive coal waste landslide at Mae Moh Mine. The failure was about 4.8 km long and 1.4 km wide

As I noted in an earlier post on this blog, 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. News reports have indicated that this failure, which occurred in a slope formed from coal waste material, caused significant damage.

Unfortunately, this area is very often cloudy, so obtaining good satellite imagery is a challenge. However, Planet captured an image on 15 November 2025 that shows a substantial part of the landslide.

The image below was captured on 28 October 2025, showing the site:-

The site of the 4 November 2025 landslide at Mae Moh Mine in Thailand. Image copyright Planet, captured on 28 October 2025, used with permission.

This image shows the aftermath of the landslide:-

The aftermath of the 4 November 2025 landslide at Mae Moh Mine in Thailand. Image copyright Planet, captured on 15 November 2025, used with permission.

And here is a slider to allow the images to be compared:-

Images copyright Planet

The crown of the landslide is to the west, with movement in an eastward direction. The landslide is very large – a rough estimate is 4.77 km long and 1.37 km wide. The archive of satellite image suggests that three was large-scale dumping of mine waste in the area that became the head scarp in the weeks ahead of the landslide. This freshly deposited material can be clearly seen in the pre-failure material, and is also discernible, after the failure. The presence of this material is a good starting point in terms of understanding the causes.

Cleaning up this site is going to be a very major, and very expensive, task.

Reference

Planet Team 2025. 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
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

SummaryCentral America’s tectonic complexity arises from the interaction of multiple plates and diverse plate boundaries, resulting in high seismic activity and intricate subduction processes. Three-dimensional seismic velocity models can provide critical constraints on subduction processes and associated earthquake hazard models. Although regional tomographic studies have offered insights into seismic activity and lithospheric processes in Central America, there have been few studies that image the entire region in a consistent manner, likely due to the geological complexity and numerical challenges. In this study, we develop a new high-resolution three-dimensional (3-D) compressional (P)-wave velocity model to investigate the subduction dynamics of the region. We apply the teletomoDD method, which uses both local and global body-wave arrivals to resolve velocity structures. We use the International Seismological Center’s EHB catalog to extract data from 6,026 regional earthquakes from 1965 to 2019, recorded by seismic stations both inside and outside of our study area. Our model is further constrained by incorporating about 30,000 global events recorded by the seismic stations within our study area. We perform both checkerboard and restoration tests to assess the resolution of the model and find that the main features are resolved robustly regardless of the initial models. The model shows a coherent high-velocity anomalies along the Middle America Trench at 50 km depth, suggesting cold, dense subducting slabs. It also captures notable variations in slab geometry, including a slab window in the southern Cocos region starting at ∼75 km depth. Low-velocity anomalies beneath major volcanic systems such as the Central American Volcanic Arc and the Trans-Mexican Volcanic Belt point to slab dehydration, fluid migration, and partial melting processes, whereas the discontinuous distribution of volcanism in Mexico and Central America appears to be influenced by the subduction of the Cocos Plate. Additionally, we identify high-velocity anomalies near the Siqueiros and Clipperton Transform Faults on the East Pacific Rise, possibly caused by mafic magmatic cumulates. The high-velocity anomaly near Swan Islands Transform Fault may reflect locally increased density inferred from previous gravity studies. Our new velocity model offers a consistent seismic structural foundation for further investigations into seismogenic processes, slab geodynamics, petrology, and rheology in Central America.

SummaryRecently, semi-airborne transient electromagnetic (TEM) systems have gained attention in geophysical investigations due to their ability for fast mapping and minimal ground access requirement. These systems consist of a ground-based transmitter source and an inductive receiver coil, carried by an uncrewed aerial vehicle. This study investigates how transmitter source selection in field-based semi-airborne TEM systems affects model parameter uncertainty, using synthetic subsurface models. The simulated dB/dt responses highlight distinct signal characteristics between the galvanic-based system (herein galvanic source) and the inductive-based system (herein inductive source), with differences observed across varying subsurface conditions. An analysis of four synthetic 3-layer models highlights that the inductive-based system resolves shallow conductors better at short offsets, whereas the galvanic-based system is better at resolving parameters for deeper targets at large offsets. Both systems, however, face challenges in accurately resolving resistive targets embedded between conductors, highlighting the need for strategic selection of the transmitter source. The galvanic-based system consistently achieves a higher signal-to-noise ratio (SNR), particularly at large offsets, making it better suited for deep exploration. In contrast, the inductive-based system exhibits lower SNR, higher noise susceptibility, and sign-changing dB/dt responses at increasing offsets adding complexity to data processing and interpretation. Despite these limitations, inductive-based systems enable earlier time measurements with signal magnitudes at short offsets comparable to galvanic-based, due to shorter current turn-off times. In this analysis we have used two system setups utilizing inductive and galvanic sources that reflect commonly used systems, but obviously, assumptions regarding transmitter characteristics such as type, size, waveform, and current amplitude, will influence the results when examining details more closely.

Soil stores more carbon than Earth's atmosphere and plants combined, which makes the speed of soil carbon's decomposition an important variable in models used to predict changes to our climate.

Scientists have revealed that ancient bogs in the Southern Hemisphere hold clues to a major shift in Earth's climate thousands of years ago.

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

The Hawaiian Islands formed through the Pacific plate’s movement over a relatively stationary, hot mantle plume, creating a succession of progressively older volcanic centers. New land continues forming on the Big Island’s south side, where the Kīlauea volcano system has remained active for decades. After nearly 40 years of spectacular surface flows entering the sea at Pu’u’ō’ō, volcanic activity shifted to the summit caldera.

Wu et al. [2025] employ seismological techniques to analyze subtle changes in shallow crustal velocities from 2013 to 2018, combining these data with geodetic and geological observations to better understand magma reservoir interactions between Kīlauea’s caldera and Pu’u’ō’ō. Their analysis reveals a fascinating sequence of cross-communication involving pressurization and magma transport processes affected by earthquake valving. When integrated with other monitoring and modeling, such research provides valuable insights into Kīlauea’s plumbing and basaltic volcanic systems more broadly. The work also reemphasizes the importance of seismological monitoring, and deployment of dense seismic networks at as many active volcanoes as possible would enable new comparative analyses.

Citation: Wu, S.-M., Lin, G., & Shearer, P. (2025). Seismic velocity monitoring reveals complex magma transport dynamics at Kīlauea Volcano prior to the 2018 eruption. AGU Advances, 6, e2025AV001759. https://doi.org/10.1029/2025AV001759

—Thorsten Becker, 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.

Publication date: November 2025

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 276

Author(s):

Publication date: November 2025

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 276

Author(s): Noorfarhah Jasmin Jamaludin, Ahmad Fikri Abdullah, Nur Atirah Muhadi, Aimrun Wayayok

Publication date: November 2025

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 276

Author(s): Jitendra Rajput, Nand Lal Kushwaha, Aman Srivastava, Dinesh Kumar Vishwakarma, A.K. Mishra, P.K. Sahoo, Truptimayee Suna, Lalita Rana, Malkhan Singh Jatav, Jitendra Kumar, Dimple, Shaloo, Himani Bisht, Ashish Rai, Bilel Zerouali, Chaitanya B. Pande, A. Elbeltagi

Publication date: November 2025

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 276

Author(s): Chengming Zhang, Xin Liu, Shuyi Chen, Jianrong Bi, Yonghang Chen, Qing He, Ting He, Yunhong Xu, Hui Li

Publication date: November 2025

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 276

Author(s): Deevi Prathima, A.N.V. Satyanarayana

Publication date: November 2025

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 276

Author(s): Fan Wu, Congming Dai, Cong Zhang, Wentao Lian, Shunping Chen, Heli Wei

Publication date: Available online 17 November 2025

Source: Advances in Space Research

Author(s): Mohd Adha Abdul Majid, Nurul Hazrina Idris, Mohd Nadzri Md Reba, Stefano Vignudelli