EOS

Local reports suggested that over 1,500 people died in this event, and a high death toll was reported by some international agencies. However, examination of satellite imagery casts significant doubt on this interpretation.

It has been widely reported that on 31 August 2025, a devastating landslide occurred at Tarasin (there are various spellings of this place) in the Marrah Mountains in Central Darfur, Sudan. Initial reports indicated that 1,000 people had been killed, making this the most deadly landslide of 2025 to date, whilst subsequent reports elevated this number to over 1,500. The reports were given credence by organisations such as Save the Children, who reported that 373 bodies had been recovered. There was only one reported survivor of the disaster.

However, it should also be noted that this very high total was not supported by government reports – noting of course that Sudan has extensive civil conflict, and that this area is not controlled by the government. BBC Verify examined the event too using Maxar satellite data, but could not identify a village that had been destroyed. The Washington Post reported that the United Nations subsequently reduced their estimated total loss of life to “scores”. On Bluesky, Dan Shugar pointed out that the reporting of 1,000 fatalities does not really stack up. The HydrologyNL Bluesky account has also posted some interesting analysis of this event.

The location of this landslide event is [13.01697, 24.38774]. This is a Planet image of the site draped onto the Google Earth DEM:-

Satellite image of the aftermath of the 31 August 2025 landslides in Sudan. Planet image draped onto the Google Earth DEM. Image copyright Planet, used with permission. Image dated 6 September 2025.

The marker highlights the rear scarp of the largest failure, although there are several landslides in the image. These landslides correlate with images from the site posted by news organisations (there are some images of unrelated landslides too, plus some AI slop). It appears that there have been multiple shallow landslides than have transitioned into channelised debris flows.

And this is a Google Earth view, with imagery from 2023 (with some cloud), showing the same area:-

The site of the 31 August 2025 landslides in Sudan. Google Earth image from 2023.

Some local reports of these landslides suggest that 1,500 houses were destroyed, based on information from the Sudan Liberation Movement. However, it is also notable that none of the published photography shows destruction on this scale. And the Google Earth images do not show any large settlements in the path of either the landslides themselves or the channelised debris flows. There is a cluster of houses at the foot of the main failure that has been destroyed:-

A cluster of buildings subsequently destroyed by the 31 August 2025 landslides in Sudan. Google Earth image from 2023.

However, this is a small number of buildings, not on the reported scale of losses. I have also looked at the Planet imagery from just before the landslide. There is no evidence of a large settlement in this area.

Thus, a reported death toll of 1,000-1,500 seems highly improbable, and the loss of 1,500 houses is not supported by the imagery or photography.

So, what are the possible explanations? We might consider the following:

1. The location is wrong – and the reports describe an event somewhere else. I consider this to be low probability, given the images that have been published;
2. Dan Shugar suggested that perhaps some sort of social event occurred in the path of the landslide – a wedding or suchlike. But the local reports are of 1,500 houses lost, and in general my experience is that this type of circumstance is reported, given the nature of the tragedy. Again, low probability.
3. The losses occurred a long distance down the channel. I cannot find such a site on the imagery, and I would expect that the location would be reported, and that photography would show the devastation. Again, this would seem to be low probaility.
4. There is mis-reporting, either accidentally or deliberately. I consider this to be high probability.

In remote areas, we have previously seen vastly inflated estimates of loss of life – a recent example was the 24 May Kaokalam landslide in Papua New Guinea. This can simply be a misunderstanding or the result of rumours. On the other hand, it can be deliberate. For example, loss of life can be inflated to attract additional resource for a population that is suffering extreme poverty, or it can be an attempt by the local forces to attract supplies for their own purposes. Others will be able to judge the most likely explanation.

I’m struggling to understand why reputable international agencies would appear to support these inflated reports, especially where they appear to provide testimony from the site.

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
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In 2018, the Hayabusa2 mission successfully encountered asteroid Ryugu. The Japan Aerospace Exploration Agency (JAXA) spacecraft arrived at, touched down on, collected samples of, and lifted off from the asteroid. It returned samples to Earth in 2020.

With plenty of fuel left for its extended mission, called Hayabusa2# or “Hayabusa2 Sharp,” the spacecraft raced off to its next objective, a high-speed flyby of asteroid 98943 Torifune in 2026. If all goes well with that rendezvous, the craft will attempt its final objective: an encounter with and touchdown on asteroid 1998 KY26 in 2031.

But that final objective may prove more difficult than initially imagined. New ground-based observations of 1998 KY26 have revealed that the asteroid is 3 times smaller than previously thought and spins twice as fast.

“We found that the reality of the object is completely different from what it was previously described as,” Toni Santana-Ros, lead author of a new study on 1998 KY26 and an asteroid researcher at Universidad de Alicante and Universitat de Barcelona in Spain, said in a statement.

Small and Fast

Astronomers discovered 1998 KY26 in 1998 when it came within 2 times the Earth-Moon distance. Radar and visual observations shortly after discovery estimated that the asteroid was about 30 meters across and rotated once every 10.7 minutes, the fastest-rotating asteroid known at that time. As the asteroid moved away, it became too faint to see for more than 2 decades. When Hayabusa2’s mission scientists selected targets for its extended mission, they relied on those 1998 calculations.

The asteroid completes one spin every 5 minutes and 21 seconds, less time than it takes to listen to Queen’s “Bohemian Rhapsody.”

Finally, in 2024, 1998 KY26 came close enough to Earth—12 times the distance to the Moon—to observe again. Using four of the most powerful ground-based telescopes available, Santana-Ros and his colleagues watched the diminutive asteroid tumble and spin from multiple angles, allowing them to calculate a more accurate spin rate than was possible with the limited radar and photometry in 1998.

They calculated that the asteroid completes one spin every 5 minutes and 21 seconds, less time than it takes to listen to Queen’s “Bohemian Rhapsody.” The team then combined those new observations with the 1998 radar data to recalculate the asteroid’s size. They found that instead of being roughly 30 meters in diameter, 1998 KY26 is just 11 meters, or about the length of a telephone pole. The team published these results in Nature Communications on 18 September.

Asteroid Ryugu (left) is roughly 82 times the size of asteroid 1998 KY26 (right). Credit: ESO/M. Kornmesser; Asteroid models: T. Santana-Ros, JAXA/University of Aizu/Kobe University, CC BY 4.0

“The smaller the asteroids get, the more abundant they are—but that also means that they are harder to find,” explained Teddy Kareta, a planetary scientist at Villanova University in Pennsylvania who was not involved with the new discovery. “The fact that this new paper finds such a small size for KY26 is tremendously interesting on its own—Hayabusa2 will be able to explore an extremely understudied population—but it also means that we might not have a tremendous number of known objects to compare to as well.”

A Challenge and an Opportunity

The new size and spin measurements of 1998 KY26 will make Hayabusa2’s planned touchdown more challenging, the researchers wrote. However, this is not the first time that an asteroid rendezvous mission has had to adjust its expectations mid-flight. Both Ryugu and Bennu, the first target of NASA’s Origins, Spectral Interpretation, Resource Identification, Security–Regolith Explorer (OSIRIS-REx) mission, had rougher surfaces than expected, requiring the respective missions to adjust their sample collection methods. Too, the OSIRIS-REx team learned that Bennu was actively spitting out material only when the spacecraft got close, which led them to change their plan for orbital insertion.

Despite the new challenges with 1998 KY26, Hayabusa2#’s team has a big advantage: 6 years to rework their game plan.

“The Hayabusa2 team are incredibly smart, hardworking, and have a ton of experience under their belts, but I’m sure that this kind of result is causing a bit of hand-wringing and concern for them even if the spacecraft is fully capable,” Kareta said.

“We have never seen a ten-metre-size asteroid in situ, so we don’t really know what to expect and how it will look.”

“I’m sure even the team has their doubts about whether or not the original plan was possible, but if I had to bet money, I still think the team will try [to touch down],” they added. “You set yourself up for success by building a great spacecraft and collecting a great team of engineers and scientists to staff it, but it’s still a bet every time you try something new.”

Even if a touchdown on 1998 KY26 ultimately proves impossible and Hayabusa2# simply flies on by, asteroid scientists will still gain valuable information about an incredibly common but hard-to-spot type of small asteroid.

“We have never seen a ten-metre-size asteroid in situ, so we don’t really know what to expect and how it will look,” Santana-Ros wrote.

“In many ways, a spacecraft visit to it now is even more exciting than it was before,” Kareta said.

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

Citation: Cartier, K. M. S. (2025), Hayabusa2’s final target is 3 times smaller than we thought, Eos, 106, https://doi.org/10.1029/2025EO250353. Published on 18 September 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
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Source: AGU Advances

Streamflow drought—when substantially less water than usual moves through rivers—can seriously disrupt the welfare of nearby communities, agriculture, and economies. Synchronous drought, in which multiple river basins experience drought simultaneously, can be even more severe and far-reaching.

Recent observations and modeling suggest that on the Indian subcontinent, where major rivers support more than 2 billion people, the likelihood of synchronous drought is increasing as summer monsoons weaken, the Indian Ocean warms, and anthropogenic emissions and excessive groundwater pumping continue. However, little is known about the long-term patterns of synchronous drought in India, in part because streamflow data don’t offer information about the distant past.

By combining several decades of streamflow measurements from 45 gauge stations along India’s major rivers with high-resolution temperature and precipitation data and data from a range of paleoclimate proxies, Chuphal and Mishra have now reconstructed streamflow records across more than 800 years.

To look farther back in time, the researchers turned to the Monsoon Asia Drought Atlas, which comprises tree ring data indicating summer drought conditions across Asia between 1200 and 2012. They also considered historical records of climate patterns like El Niño, the Pacific Decadal Oscillation, and the Indian Ocean Dipole to explore connections among drought frequency, reoccurrence, and synchronicity. And they used two models from the Paleoclimate Modeling Intercomparison Project Phase 4 (PMIP4) that are part of the Coupled Model Intercomparison Project Phase 6 (CMIP6) to simulate precipitation and temperature data, as well as a hydrological model to simulate streamflow from 1200 to 2012.

With all this information, the researchers created their own reconstruction model that captured historical droughts driven by monsoon failures and connected low river levels to periods of drought-induced famine. Their findings revealed an increased frequency in synchronous drought between 1850 and 2014 compared with preindustrial centuries—an increase they surmise was likely caused by the warming climate. The researchers also suggest that future synchronous droughts may threaten water security throughout India. (AGU Advances, https://doi.org/10.1029/2025AV001850, 2025)

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

Citation: Owen, R. (2025), Droughts sync up as the climate changes, Eos, 106, https://doi.org/10.1029/2025EO250324. Published on 18 September 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
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In recent years, the North American beaver (Castor canadensis) has been increasingly recognized as a valuable on-site engineer to help communities meet water management goals. Beavers are famously “eager” to build dams, which slow the flow of streams and allow wetland areas to grow.

Until now, however, land managers didn’t have a way to estimate how much water beaver reintroduction could actually bring to a habitat. Not every beaver dam results in a sprawling ponded complex; sometimes they result in smaller areas with less water retention than meets the needs of the community.

In a study published last month in Communications Earth and Environment, researchers from Stanford University and the University of Minnesota were able to link the amount of surface water in beaver ponds across the western United States to the features in those landscapes that make beaver ponds bigger.

Big, Beautiful…Beaver Ponds

Oftentimes, beavers will chain together multiple dams and ponds to form beaver pond complexes. The complexes increase an area’s water retention, cool water temperatures, and provide natural firebreaks. These wetland habitats also give the semiaquatic rodents ample room to roam and allow other species (such as amphibians, fish, and aquatic insects) to flourish.

Beaver pond complexes like the one in Happy Jack Recreation Area create habitat for wetland creatures big and small, like this (very large) moose. Credit: Emily Fairfax

“Our models highlight the landscape settings where ponds grow largest, helping target nature-based solutions under climate stress.”

The advantages of beaver pond complexes aren’t going unnoticed—the reintroduction of beavers to the North American landscape is an increasingly popular strategy for land managers looking to naturally improve a waterway.

“Managers need to know where beaver activity—or beaver-like restoration—will store the most water and maximize the environmental benefits, such as providing cooling and enhancing habitat quality” said Luwen Wan, a postdoctoral scholar at Stanford and the new study’s lead author. “Our models highlight the landscape settings where ponds grow largest, helping target nature-based solutions under climate stress.”

While improving water retention is a goal of many watershed management projects, especially in the increasingly drought-prone western United States, the researchers also emphasized that creating the largest possible ponds might not be the right solution for every area.

“It’s worth thinking about what we are actually asking of these beavers, and is that reasonable?”

“Bigger ponds are not always better,” said Emily Fairfax, coauthor on the study and assistant professor at the University of Minnesota. Fairfax explained that larger ponds are great for when the goal of the project involves water retention, but smaller ponds could be a better fit for a project in which the goals are pollution removal or increasing biodiversity. “It’s worth thinking about what we are actually asking of these beavers, and is that reasonable?”

How to Design a Dream Stream

Speaking on the main findings of the study, Wan said that she and her colleagues “found a clear link between the total length of beaver dams and the size of the ponds they create.” Additionally, they observed that the biggest ponds were found “where dams are longer, stream power is lower to moderate, and woody vegetation is of moderate [6–23 feet, or 2–7 meters] height.”

Included in the study were 87 beaver pond complexes across the western United States, encompassing almost 2,000 dams. Using high-resolution aerial imagery from the National Agriculture Imagery Program (NAIP), the team was able to connect the observed ponded area to different landscape measurements like soil characteristics, stream slope, vegetation metrics, and more.

The researchers chose NAIP imagery for its high spatial resolution and ability to cover large areas (visiting every beaver pond in the field would take too much time). Wan noted that while NAIP aerial imagery was the right fit for this project, it isn’t perfectly beaver proof. The imagery is updated every 2–3 years during the growing season, which may introduce some errors, like missing ponds even when dams have already been constructed.

Using remote sensing to predict where beaver reintroduction would be a successful match to the needs of a watershed isn’t a new idea. One frequently used model mentioned in the study is the Beaver Restoration Assessment Tool (BRAT). BRAT allows researchers to identify how many dams a given stream would likely be able to host. “That’s really important information to have,” said Fairfax, “but that doesn’t tell us how big the dams are, or how much water they could be storing.”

When Beavers Aren’t Best

Findings from this study are also helpful when selecting sites for beaver dam analogs (BDAs). These human-made structures are alternatives to beaver reintroduction that mimic beaver dams to achieve the same ecosystem benefits the beavers would bring. They are often the right tool when a waterway is too degraded to host a beaver population.

BDAs raise water levels and allow the preferred foods of beavers (such as willows and alders) to take root, giving “a little push” to the process of reestablishing a beaver population, explained fluvial geomorphologist and associate professor Lina Polvi Sjöberg from Umeå University in Sweden. Polvi was not involved in the new study.

Fairfax added that BDAs are a useful tool but are not equivalent to actual beaver dams. With beaver dams, a living animal is always present, so the land managers can count on the “maintenance staff on-site” to constantly update and monitor the waterway.

The Beavers Are Back in Town

North American beaver populations are still on the rebound from a long history of trapping and habitat loss that came with European colonization of the continent. “We are at maybe 10% of the historic population, and we actually don’t know if it’s still growing,” Fairfax said. Modern threats to beaver populations include highways and man-made dams, she added, which prevent beavers from freely moving back to places they once were.

Not everyone is quick to welcome North America’s largest rodent back to their neighborhood with open arms. Though public perceptions of beavers are shifting from pest to watershed management partner, the potential for contention still remains. Beavers occasionally build their dams in less-than-ideal locations, a situation that can result in flooded private properties and damaged infrastructure. The study notes that human influence (like trapping and land use conflicts) is a factor that land managers must consider but is not captured in statistical models.

Beavers Worldwide

The researchers found what makes beaver dams bigger in the western United States, but scientists say it will be important to replicate this study in different regions of North America, especially as beaver habitat expands northward as a result of climate warming.

“North American beavers are all one species, Castor canadensis. A beaver in Arizona is the same species as a beaver in Alaska. They all have the same instincts,” said Fairfax, “but beavers also do learn and adapt to their environments pretty strongly.”

She added that beavers will use the materials available to them, such as a colony in Yukon, Canada, that has been observed using rocks as dam-building material. “Whenever we build a model that describes what beavers are doing, there is a chance that it’s going to have a strong geospatial component to it,” Fairfax said.

Polvi agreed, stating that she hadn’t seen many studies using remote sensing methods to estimate the suitability of a stream for beaver reintroduction outside of the western United States. Putting things into a wider perspective, she added that some defining features of the American West, like the semiarid climate and large expanses of undeveloped public land, aren’t applicable to other regions of the world.

In an email, Wan said the next steps from this study include further exploring beavers’ ponded complexes across larger areas and “quantifying the ecosystem services these ponds provide, such as enhancing drought resilience.”

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

Citation: Baysinger, M. (2025), What makes beaver ponds bigger?, Eos, 106, https://doi.org/10.1029/2025EO250341. Published on 18 September 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
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Source: Global Biogeochemical Cycles

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

多年来，海洋学家们一直困惑于为何算法会在南极偏远海域的卫星图像中检测到神秘的高浓度颗粒无机碳 (PIC)。在其他地区，高PIC是单细胞浮游植物大量繁殖的标志，这种浮游植物被称为颗石藻(coccolithophores)，这些植物闪亮的碳酸钙外壳会将光线反射回卫星。然而，长期以来人们一直认为这些极地水域温度过低，不适合颗石藻生长。

如今，得益于 Balch 等人的最新船载测量数据，这个谜团终于解开了。他们发现了一种名为硅藻(diatoms)的不同类型的浮游植物，当硅藻的反射性硅质外壳（或称硅藻壳，frustules）浓度极高时，其反射率可以模拟 PIC 的反射率。这种反射率可能导致卫星算法将这些遥远的南部海域错误地归类为高 PIC 区域。

同一研究团队此前的船上观测已证实，来自颗石藻的PIC是大方解石带的成因——大方解石带是一个巨大的、季节性的、反射性的水环，环绕南极洲北部较温暖的水域。然而，在更南端，南极大陆周围异常明亮的区域仍然无法解释，推测的成因包括松散的冰块、气泡或反射性的冰川“粉”（被侵蚀的岩石颗粒）被释放到海洋中。

研究人员乘坐R/V Roger Revelle号从夏威夷向南航行，进入较少被探索的水域，这里以冰山和波涛汹涌的大海而闻名。他们测量了PIC和二氧化硅的含量，确定了光合作用速率，进行了光学测量，并在显微镜下观察了微生物。这些数据表明，这些偏远地区的高反射率主要是由硅藻壳引起的。

然而，研究人员也惊讶地发现极地水域中有一些颗石藻，这表明这些浮游植物可以在比以前想象的更冷的海水中生存。

由于颗石藻和硅藻在海洋碳固定中都发挥着重要作用，因此这些发现可能对地球的碳循环具有重要意义。研究人员表示，这项研究还可以为改进卫星算法提供参考，以便更好地区分PIC和硅藻壳。(Global Biogeochemical Cycles, https://doi.org/10.1029/2024GB008457, 2025)

—科学撰稿人Sarah Stanley

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

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

Today, in Eos, American Geophysical Union (AGU) Publications recognizes a number of outstanding reviewers for their work in 2024, as selected by the editors of each journal.

Peer review is a crucial component of the scientific process and is vital for promoting clarity and accuracy in how science is communicated.

Peer review is a crucial component of the scientific process and is vital for promoting clarity and accuracy in how science is communicated. In an era with so many ways to share ideas and research, a healthy and thriving system of peer review ensures that we encourage clear communication and maintain the highest integrity in our scientific publications. At AGU, the peer review process is conducted by scientists, starting with the journal editors. It is then the peer reviewers who take time away from their own research to volunteer time and expertise to help other scientists improve their articles and to aid publication decisions. The work of these colleagues ensures that thousands of articles each year receive independent feedback as part of a robust process of consideration and evaluation for publication. We are thankful for their efforts to make our science stronger.

Discoveries and solutions in the Earth and space sciences rely on increasingly complex approaches and datasets reflected in the papers that share their results. Peer reviewers bring their substantial expertise to evaluate detailed and intricate science conducted by teams of researchers large and small. Reviewers must assess insights gleaned from studies utilizing more and new techniques, data, and simulations that increase in scale and scope each year. As a result, both the value and challenge of peer reviewing keeps growing. Science benefits when our community rises up to support the opportunities afforded by the work reported in AGU journals by providing thoughtful and insightful feedback through peer review.

The outstanding reviewers listed here have provided in-depth, valuable, and timely feedback and evaluations, often through multiple revisions, and multiple manuscripts, that have led to clearer and greatly improved final published papers. Their contributions helped raise the quality of submissions received from around the world, delivering valuable feedback that makes for better scientific discourse.

Many Reviewers: A Key Part of AGU Journals

While we recognize these few outstanding reviewers, we also must acknowledge the incredible service to the community by all the researchers who have conducted reviews to help ensure the quality, timeliness, and reputation of AGU journals. We also welcome new and first-time reviewers who have joined the family of community servants who act as integrity stewards and have been providing authors with valuable feedback to improve their science and communication. In 2024, AGU received over 20,000 submissions, which was a significant increase from 2023, and published 7,517 papers. Most submissions were reviewed multiple times—in all, 17,947 reviewers completed 44,656 reviews in 2024.

The past several years continued to be a rollercoaster for researchers, editors, and peer reviewers. The challenges of maintaining the peer review system remain at an all-time high. Volunteer reviewers in Europe and the United States receive more invitations than they can accept, while research output in China is now the highest of any country. AGU journals continue to make progress in balancing the efforts of colleagues serving our community via conducting peer reviews even as they often struggle to invite a proportional number of reviewers across the globe. Likewise, early career researchers observe some of their more senior colleagues being overburdened by invitations and wonder why they receive so few invitations themselves. AGU is committed to building further entrance points to peer reviewing including its co-reviewing program and peer reviewing programs in individual journals.

Reviewers play a central role in the rapid feedback and publishing of new science that is at the heart of advancing the Earth and space sciences.

Amidst these challenges, each AGU journal worked to maintain low time frames from submission to first decision and publication, and consistently maintained industry-leading standards. Reviewers play a central role in the rapid feedback and publishing of new science that is at the heart of advancing the Earth and space sciences.

Editorials in each journal express our appreciation along with reviewer recognition lists. Our thanks are a small acknowledgment of the large service that reviewers bear in improving our science and its role in society.

Additional Thanks

In addition, we are working to highlight the valuable role of reviewers through events at AGU’s Annual Meeting and other meetings.

We will continue to work with the Open Researcher and Contributor ID (ORCID) network to provide official recognition of reviewers’ efforts, so that reviewers receive formal credit there. As of 10 July 2025, we have over 116,000 ORCIDs up from 100,000 ORCIDs one year ago.

Getting Your Feedback

We value your feedback, including ideas about how we can recognize your efforts even more, improve your experience, and increase your input on the science. Feel free to send your comments to publications@agu.org. We look forward to hearing from you!

Once again: Thanks to our Outstanding Reviewers of 2024!

—Matt Giampoala (mgiampoala@agu.org, 0000-0002-0208-2738), Vice President, Publications, American Geophysical Union; and Steven A. Hauck II (0000-0001-8245-146X), Chair, AGU Publications Committee

Citation: Giampoala, M., and S. A. Hauck II (2025), In appreciation of AGU’s outstanding reviewers of 2024, Eos, 106, https://doi.org/10.1029/2025EO255029. Published on 18 September 2025. This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). Text © 2025. The authors. CC BY-NC-ND 3.0
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Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Planets

In four years, NASA’s Psyche mission will arrive at asteroid 16 Psyche, a mysterious metallic-type (or M-type) asteroid that will be the first of its kind to be visited by a space mission. Observations of 16 Psyche’s surface suggest that it is highly metal-rich, but the bulk density of the asteroid is inconsistent with being totally made of metal. There are several hypotheses for Psyche’s origin and metallic spectra, including ferrovolcanism, which hypothesizes that metallic melts are squeezed out of the crystallizing core of the asteroid and erupt as lava flows on the surface.

The model adopts a primitive meteorite bulk composition and determines the composition and density of different internal layers of the asteroid. The metal core crystallizes from the outside moving inward (solid Fe+FeNi layer). The subsequent build-up of pressure in the liquid Fe-S layer may be high enough to allow it to erupt outward to the surface. Credit: Jorritsma and van Westrenen [2025], Figure 3

Jorritsma and van Westrenen [2025]  are the first scientists to look at whether ferrovolcanism is actually possible given what we know of the meteoritic precursors for Psyche’s composition. By calculating core sizes, compositions, and densities for different meteorite types the scientists calculate buoyancy forces and excess pressures to determine if the metallic liquid would be mobile enough to produce ferrovolcanism.

They found that some meteoritic compositions could produce ferrovolcanism while others could not. If NASA’s Psyche mission finds evidence of ferrovolcanism on the asteroid’s surface, these models can help constrain its early history and composition.

Citation: Jorritsma, J. J., & van Westrenen, W. (2025). Constraints on the feasibility of ferrovolcanism on asteroid 16 Psyche. Journal of Geophysical Research: Planets, 130, e2024JE008811. https://doi.org/10.1029/2024JE008811

—Laura Schaefer, Associate Editor, JGR: Planets

Text © 2025. The authors. CC BY-NC-ND 3.0
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Planet satellite imagery has started to reveal the events that killed 70 people at in northern India. It clearly indicates that intense rainfall triggered landslides that transitioned into channelised debris flows.

On 5 August 2025, a series of terrifying landslides struck Dharali in Uttarkashi, Uttarakhand, northern India. I blogged about this at the time – the Wikipedia page for the disaster indicates that about 70 people were killed.

In the aftermath of the disaster, there was some very strange speculation about the cause. For example, the Times of India quotes an expert from the India Meteorological Department as follows:

“Only very light to light rain was observed in the affected area over 24 hours. The highest rainfall recorded anywhere in Uttarkashi was merely 27mm at the district headquarters.”

They quote another scientist as follows:

“This volume is insufficient to trigger floods of such severity, suggesting a powerful event such as a glacier burst or a GLOF.”

They also quote a senior geologist as follows:

“Such disasters occur when water accumulates at higher elevations and discharges suddenly … Heavy rainfall alone can’t cause such a disaster.”

This is of course a nonsense. Intense rainfall is highly spatially variable, especially in high mountains. Take a look at this “Black Rainfall” event in Hong Kong (which was not in a high mountain area, where the events are even more extreme, but Hong Kong has a fantastic rain gauge network):-

Hong Kong Observatory data showing the distribution of precipitation in a “Black rainfall” event in 2020. Credit: Hong Kong Observatory

The western and southern parts of Lantau island received less than 40 mm of rainfall that day, whilst the area around Sha Tin received over 400 mm. The distance between the boundary of >400 mm and <40 mm is a few kilometres.

Cloudburst precipitation is incredibly spatially variable, so it is not the case that a failure to record heavy rainfall on a sparse rain gauge network means that such events did not occur. And, as I have shown on numerous occasions on this blog, intense rainfall most certainly can, and does, trigger catastrophic debris flows.

However, there was a stronger piece of evidence that suggests that this event was not a glacier burst or a GLOF. On 5 August 2025, the debris flows occurred in two separate, but adjacent catchments, one at Dharali but another at Harshil, about 500 m to the west. These two catchments are not connected, but they are separated by a ridge. This would suggest a common trigger – in the absence of an earthquake, a localised rainfall event is highly likely (especially in the peak of the monsoon).

Of course, to be sure we need either fieldwork or satellite imagery. In the rainy season, this is really hard to achieve but as the monsoon withdraws this becomes possible. And sure enough, on 11 September 2025, Planet captured a fabulous satellite image that starts to reveal the story.

So let’s start with Harshil – the picture here is straightforward. The slider below shows Harshil and the lower part of the catchment using Planet imagery draped onto the Google Earth DEM. Note that the change in the topography is not captured in the DEM.

A comparison of Harshil before and after the 5 August 2025 Dharali disaster. Images by Planet, using the Google Earth DEM.

The path of the debris flow is clear, and upstream there is a very obvious large landslide. Thus, the most likely cause of the Harshil debris flow is that slope failure.

The image below shows the landslide itself, but again note that the topography in the DEM has not updated, so the morphology is distorted. But this is clearly a large rock slope failure.

I will caveat to say that at this stage we cannot definitively say that this landslide occurred on 5 August 2025, but Occam’s razor implies that this is the cause.

The landslide upstream from Harshil after the 5 August 2025 Dharali disaster. Image copyright Planet, used with permission. Image dated 11 September 2025.

This slope failure has released a huge amount of sediment into the catchment. This will cause problems for Harshil in the future.

So now let’s turn to Dharali itself. This is more complex. We have to go high up into the catchment above the village to see what’s happened. The slider below shows before and after Planet images of the upper part of the catchment above Dharali:-

Planet images showing the upper part of the catchment above Dharali before and after the 5 August 2025 disaster. Images by Planet using the Google Earth DEM.

There has been substantial change on both sides of the catchment. Let’s start with the west (the right side of the image above as the image is from the south looking towards the north):-

The west side of the upper part of the catchment above Dharali after the 5 August 2025 disaster. Image copyright Planet, used with permission. Image copyright Planet, used with permission. Image dated 11 September 2025.

The juxtaposition of the sediments lower down the valley suggests to me that this was the cause of the first (most catastrophic) debris flow at Dharali. The image strongly indicates that this was a channelised debris flow initiated by a landslide in glacial sediments in the upper part of the catchment. There was a huge amount of entrainment of channel sediments downstream. Note that there is a pre-existing, smaller, landslide at this site.

Thus, the major debris flow at Dharali was probably initiated by a shallow landslide that transitioned into a channelised debris flow.

Events on the east side of the catchment are much less clear. I suspect that the processes here generated at least some of the smaller debris flows that struck Dharali after the first event. This is the Planet image for this side of the valley:-

The east side of the upper part of the catchment above Dharali after the 5 August 2025 disaster. Image copyright Planet, used with permission. Image copyright Planet, used with permission. Image dated 11 September 2025.

The changes to the fan in the centre of the image are notable, but what caused this? I am not entirely sure. A closer comparison of the glacial sediment above this fan looks like this:-

Planet images showing the upper part of the catchment above Dharali before and after the 5 August 2025 disaster. Images by Planet using the Google Earth DEM.

In the foreground is a trough that has suffered extensive erosion. But there is also major change in the slopes above that trough. I have a suspicion that the feature that I have highlighted below might be quite significant:-

The upper eastern part of the catchment above Dharali before the 5 August 2025 disaster. Image copyright Planet, used with permission. Image dated 11 September 2025.

It appears to me that a landslide has occurred on this area of glacial sediment. Did this generate one or more channelised debris flows? There are other changes too – so maybe there were repeated shallow failures that generated the smaller debris flows observed at Dharali?

In conclusion, we can say:

1. The Dharali disaster was caused by rainfall. There is no other credible trigger that explains simultaneous events in two separate, adjacent, catchments.
2. Given the rain gauge record, this must have been a highly localised, cloudburst event.
3. Harshil was destroyed by a debris flow that probably originated from a rock slope failure in the catchment above the village.
4. The first Dharali debris flow was probably triggered by a rainfall triggered shallow landslide in glacial deposits in the upper part of the catchment, which transitioned into a channelised debris flow.
5. The subsequent debris flows at Dharali were caused by other erosive events in these glacial tills. The origin is not entirely clear, but there is evidence of at least one further shallow landslide that may have been the origin for one or more events.

This is a very provisional analysis based on lower resolution (but still brilliant) imagery. These hypotheses need to be explored through fieldwork and/or high resolution imagery.

Finally, it is absolutely inevitable that the fans at Dharali and Harshil will suffer similar events in the future. Neither will be safe for habitation.

Reference and acknowledgement

Thanks to loyal reader Jack for really interesting and stimulating discussions about these events. And special thanks to Planet for the astonishing imagery.

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

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Astronomers have recently found that roughly a third of planet-forming disks around young Sun-like stars are tilted relative to the direction that their star spins.

“All young stars start out with a disk. But the relative orientation between the disk and the star’s spin axis, little was known about that,” explained lead researcher Lauren Biddle, a planetary scientist at the University of Texas at Austin.

This discovery, published in Nature, could help answer the long-standing question of how planets come to orbit their stars at wonky angles: Maybe they were born that way.

Skewed from the Start

There’s a universal truth that when a new star collapses out of a cloud of gas, angular momentum must be conserved. That means that as the nebulous star shrinks in size, it also rotates faster, like when a spinning ice skater draws their arms in and speeds up. The surrounding leftover gas and dust flatten out into a disk that spins in the same direction as the star, and that disk may eventually form planets that spin and orbit in that same direction.

But the universe is rarely so neat and tidy.

Of the thousands of known exoplanets, dozens of them orbit at wonky angles relative to their star’s spin axis. In our own solar system, the plane in which the eight planets orbit is tilted by about 6º from the Sun’s spin axis. Astronomers have theorized that some of these misalignments, or obliquities, result from dynamical events that take place after a planetary system has already formed: A star passes by and disturbs the orbits, or a major collision knocks a planet off course.

Some of those misalignments, however, are baked in from the start. Previous studies have attempted to observe young star systems and their planet-forming disks to see whether those disks start out tilted or aligned. But those studies were limited by the fact that not many protoplanetary disks had yet been discovered, and many of those that were known were part of binary star systems, Biddle explained. Although those studies found some tilted disks, the gravity from the binary star, rather than an intrinsic misalignment, may have been the culprit.

“If systems begin with primordially tilted orbits, then there is no need to invoke other mechanisms—many of which would destabilize neighboring planets—within those systems,” said Malena Rice, a planetary astrophysicist at Yale University in New Haven, Conn. “By understanding the range of primordial tilts and comparing that distribution with more evolved systems, we can piece together the evolutionary sequences of different classes of planetary systems.” Rice was not involved with this study.

“The one-third rate of misalignment stands independent of everything else.”

Biddle and her colleagues compiled a new sample of young star systems by combining observations of protoplanetary disks from the Atacama Large Millimeter/submillimeter Array (ALMA) and measurements of stars’ spin from the Transiting Exoplanet Survey Satellite (TESS) and retired K2 mission. Biddle explained that because ALMA, TESS, and K2 have released such large datasets, her team could curate their sample to look only at Sun-like stars that did not have any binary companions.

They found that 16 of the 49 stars in their sample (about a third) had protoplanetary disks with obliquities of at least 10°, the lower limit of what they could measure. The remaining two thirds of the systems showed no significant evidence of misalignment. This rate of high-obliquity disks is consistent with past studies but more than doubles the number of young, single, Sun-like stars for which astronomers know the degree of disk misalignment.

The 16 stars that host tilted disks did not share any obvious characteristics like mass, temperature, and size, and the disks themselves also had different sizes, masses, and structures.

“We didn’t find any correlation there,” Biddle said. “At this point, independent of other system parameters, the one-third rate of misalignment stands independent of everything else.”

Oblique Across Space and Time

Past studies have suggested that moderate disk obliquities might rise from imperfections in the nebulous cloud that formed the star system: An odd clump in the right spot might create turbulence that grows stronger as the cloud collapses, or the clump might fall onto the disk late and tip it off its axis.

“Moderate misalignments of a few tens of degrees can be produced naturally by either turbulence in the natal molecular cloud, late-stage disk accretion, or some combination of the two,” Rice said.

However, that doesn’t necessarily mean that every misaligned exoplanet, or even a third of them, started out that way.

“It would be great to take a crack at mapping stellar obliquities across space and time.”

“A misalignment between a planet’s orbital plane and its host star’s spin axis can originate in two broad phases: during the star and planet formation stage…[and] later, during the system’s main sequence lifetime,” explained Simon Albrecht, an astronomer at Aarhus University in Denmark who was not involved with this research. “If we can determine the fraction of systems that are already misaligned right after birth, that helps us distinguish between these two broad possibilities.”

Determining how much of a system’s tilt comes early or late and whether that tilt changes over a planetary system’s lifetime will require observing a lot more misaligned planetary systems at all stages of evolution, Biddle said. She added that the upcoming data release from the now-retired Gaia mission will be key to answering both of those questions.

“It would be great to take a crack at mapping stellar obliquities across space and time,” Biddle said. “Being able to fill in that time parameter space will help quantify how important dynamics is for generating that final [obliquity] distribution that we observe in planetary systems.”

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

This news article is included in our ENGAGE resource for educators seeking science news for their classroom lessons. Browse all ENGAGE articles, and share with your fellow educators how you integrated the article into an activity in the comments section below.

Citation: Cartier, K. M. S. (2025), Tilted planet system? Maybe it was born that way, Eos, 106, https://doi.org/10.1029/2025EO250338. Published on 17 September 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

To help project Earth’s future climate, it is critical to understand how the capacity of ecosystems to take up and store carbon is changing as atmospheric carbon dioxide levels rise and climate change intensifies.

Bilir et al. [2025] integrate satellite data with a model of terrestrial carbon cycling to parse regionally-specific influences of CO2 and climate on carbon storage in living and dead plant material, and the associated residence time of carbon in those pools.

For the specified regions, changes in total carbon storage (left Y axis, solid bars) and percent change in mean residence time of carbon (right Y axis, hatched bars) that can be attributed to atmospheric CO2 (top panel), climate trends (middle panel), and the combined, interacting effects of CO2 and climate (bottom panel). Credit: Bilir et al. [2025], Figure 6

Their work helps untangle the mechanisms driving what they and others have observed: that CO2 increases carbon storage more than climate effects decrease it. They find greater carbon storage in living plants globally and a shift in dead carbon storage from mid- and high latitudes to the tropics. They also demonstrate a reduction in mean carbon residence times across all latitudes. The shift in carbon storage from dead to live pools underscores the sensitivity of terrestrially-mediated carbon cycling and residence times to living plant carbon uptake and storage potentials.

These efforts help us understand, at a global scale, how rising atmospheric CO2 and climate change interact to prompt a latitudinally-specific reorganization of our planet’s terrestrial carbon cycling, and thus its climate.

Citation: Bilir, T. E., Bloom, A. A., Konings, A. G., Liu, J., Parazoo, N. C., Quetin, G. R., et al. (2025). Satellite-constrained reanalysis reveals CO2 versus climate process compensation across the global land carbon sink. AGU Advances, 6, e2025AV001689. https://doi.org/10.1029/2025AV001689

—Sharon Billings, Editor, AGU Advances

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Climate change caused 16,469 deaths in European cities this summer, new research estimates.

This summer was the fourth hottest in European history, and its effects on the continent’s population have been widely reported. Spain experienced its most intense heat wave in history in August 2025. Türkiye saw its highest recorded temperature ever (50.5°C, or 122.9°F). Finland saw an “unprecedented” three straight weeks of 30°C heat.

A new, rapid-analysis study by researchers at Imperial College London (ICL) and the London School of Hygiene & Tropical Medicine estimated that 24,400 people across 854 European cities and urban centers died from heat-related causes between June and August 2025. Using climate models and a comparison of this figure with how many heat-related deaths would have occurred in a 1.3°C cooler world, the researchers estimated that climate change was responsible for 68% of these deaths.

“These numbers represent real people who have lost their lives in the last months due to extreme heat.”

“In other words, it could have tripled the death toll,” said Garyfallos Konstantinoudis, a biostatistician at ICL’s Grantham Institute – Climate Change and the Environment.

Though the planet has warmed about 1.3°C overall since preindustrial times, Europe is warming more quickly than the rest of the planet, meaning that temperatures on the continent this summer were about 1.5°C to 2.9°C warmer than they would have been without anthropogenic warming.

In a Tuesday press conference, the researchers explained that their estimate of 16,649 climate-related deaths is likely conservative, in part because climate models are known to underestimate warming in Europe. In addition, their estimate includes only deaths in urban centers with populations above 50,000 people—areas that represent only about 30% of Europe’s population. They focused on these urban areas because these locations had greater data availability, but that means the estimate is just a snapshot.

“These numbers represent real people who have lost their lives in the last months due to extreme heat,” said Friederike Otto, a climatologist at ICL’s Centre for Environmental Policy. “Many of these would not have died if it wasn’t for climate change. And if we continue on the path that we are on now, continue burning fossil fuels, these deaths will only increase.”

The Hidden Costs of Heat

The study also notes that northern Europe experienced a higher proportion of heat-related deaths than southern Europe, despite southern Europe enduring higher heat (some cities in the region have warmed by up to 3.6°C) and more excess mortality overall. The reason is that prior to climate change, heat in northern Europe rarely reached levels that affected human health at all. Now, explained Konstantinoudis, “almost all of the heat-related deaths in northern Europe…are due to climate change.”

“Reducing fossil fuel use is one of the most important public health interventions of our time.”

Courtney Howard, vice-chair of the Global Climate and Health Alliance and an emergency physician in Canada’s Yellowknives Dene Territory, who was not involved in the study, noted that extreme heat can raise the risk of deadly heart attacks and strokes because high heat causes the heart to work harder. It can also fatally worsen respiratory conditions such as asthma because ozone pollution tends to increase during extreme heat events. Thus, many of the deaths that occur during heat waves are not necessarily recorded as heat deaths.

“The result is that heat numbers capture only a small fraction of the real story at the bedside,” she said. “Experts do not believe that we can adapt health systems adequately to cope with the temperatures that we are currently facing. That’s why reducing fossil fuel use is one of the most important public health interventions of our time.”

To estimate heat deaths, researchers turned to an existing dataset that showed relationships between temperature and mortality across the 854 urban areas used in the study. They then estimated the number of daily deaths during the heat wave using historical Eurostat data and information on which days exceeded minimum mortality temperature.

It’s Not Just Europe Click image for larger version. Credit: Imperial Grantham Institute

Among the countries included in the study, the Baltic nations of Estonia, Latvia, and Lithuania were the only three that did not experience hotter-than-usual summers.

Rome, Athens, and Bucharest saw the highest heat-related death rates per capita among European capital cities, the study found. In general, cities are hotter than surrounding areas because of the urban heat island effect, in which concrete surfaces trap heat and raise city temperatures.

Chris Callahan, a climate scientist at Indiana University Bloomington who was not involved in the study, said that though the study is not peer reviewed, its methods appear to be “standard and based on extensive peer-reviewed research.”

The researchers noted several factors their study did not consider, including cities’ efforts to adapt to climate change and all adverse health effects of heat. It also did not capture changes to baseline populations that occurred post-COVID-19, which might have led to higher numbers for some cities.

“The findings in this study are stark and concerning, as they illustrate that climate change is already the dominant influence on heat-related mortality in Europe,” Callahan told Eos in an email.

“We are warming the world through our fossil fuel emissions and other activities and that…is causing people to die.”

Europe faces particularly high risks related to climate change, he added, both because temperatures are rising more quickly in western Europe than in other parts of the world and because Europe’s aging population is highly vulnerable to heat. In fact, this study found that people over 64 made up 85% of the climate-related deaths in European cities this summer.

However, the study authors noted that the growing toll warming is taking on human health is not unique to Europe.

“The specifics will vary wherever you’re looking in the world, but the basic point of these studies will always be the same: that we are warming the world through our fossil fuel emissions and other activities and that this is causing people to die,” said Clair Barnes, a statistician at ICL’s Centre for Environmental Policy.

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

Citation: Gardner, E. (2025), Climate change may have killed 16,469 people in Europe this summer, Eos, 106, https://doi.org/10.1029/2025EO250348. Published on 17 September 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.

body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

Misunderstandings and disinformation abounded at a 16 September hearing of the Subcommittee on Delivering on Government Efficiency about geoengineering, which encompasses efforts to alter Earth systems for the purpose of mitigating climate change. 

Rep. Marjorie Taylor Greene (R-GA), chairwoman of the subcommittee, called for an outright ban on geoengineering and used the hearing to promote her Clear Skies Act, which would impose fines of up to $100,000 and potentially jail time for anyone conducting “weather modification” activities.

Geoengineering is an amorphous term that can refer to a range of climate intervention activities, including cloud seeding to spur precipitation, management of solar radiation to cool Earth by reflecting sunlight, and carbon capture and sequestration efforts.

“Today’s advocates of geoengineering don’t just want to address droughts or improve conditions for agriculture” Greene said. “They want to control the Earth’s climate to address the fake climate change hoax and head off global warming. That, of course, requires massive interventions.”

In addition to asserting that climate change is a hoax, Greene implied that climate interventions could remove enough carbon dioxide from the atmosphere to harm plant life. In questioning, Rep. Brian Jack (R-GA) repeated a dubious claim that the release of dry ice into a hurricane in 1947 in an experiment called Project Cirrus caused the hurricane to turn toward Georgia. And Rep. Pat Fallon (R-TX) argued that former Vice President Al Gore’s misrepresentation regarding the melting of the north polar ice cap invalidates decades of climate science. 

One witness during the hearing was Christopher Martz, a policy analyst and meteorologist at the Committee for a Constructive Tomorrow, an environmental policy think tank that has cast doubts on climate science. Martz received an undergraduate degree in meteorology in May and runs a weather blog that questions the influence of climate change in extreme weather events. 

 
Related

•  Marjorie Taylor Green Introduces ‘Weather Modification’ Ban
•  Watch the hearing: Playing God with the Weather — A Disastrous Forecast
•  AGU’s Ethical Framework Principles for Climate Intervention Research
•  Get Involved: AGU Science Policy Action Center
 

Martz asserted that the science behind climate change is uncertain, and therefore that climate intervention is an alarmist reaction: “Warming could be mostly natural and we just don’t know,” he said. It’s not: The vast majority of scientists agree that Earth is warming and human activities are to blame.

The hearing’s only climate scientist witness, former Lawrence Livermore National Laboratory scientist Michael MacCracken, tried to combat the climate denialism in the room. He challenged the ideas that current climate intervention efforts are sufficiently powerful or scalable enough to change a major weather phenomenon, or that they are targeted to harm the public.

Despite the falsehoods raised by Greene and others at the hearing, some of their comments aligned with how many scientists view climate intervention—as a potentially risky endeavor that requires more research before it is considered viable and safe.

AGU’s own Ethical Framework Principles for Climate Intervention Research, developed with the contributions of scientists, policymakers, ethicists, government agencies, nongovernmental organizations, and potentially impacted communities, acknowledges this perspective: “Substantial research and evaluation efforts will be required to determine the effectiveness, risks, and opportunities of climate intervention,” the framework states.

At the hearing, Greene asked “who would control the dial” if scientists managed to reliably alter Earth’s climate.

Such questions are a reason to lean into Earth systems research, said Roger Pielke, Jr., a political scientist at the conservative American Enterprise Institute who spoke at the hearing. Pielke called for Congress to enact legislation to improve oversight of geoengineering and recommended that Congress ask the National Academy of Sciences to assess what scientists do and don’t know about the effects of climate intervention activities.

Rep. Melanie Stansbury (D-NM), ranking member of the subcommittee, closed the hearing with a plea to support science. “Literally all we’re trying to accomplish by climate action is to keep our planet in some sort of balance,” she said, calling the Trump administration’s firing of federal scientists and engineers, the defunding of science agencies, the firing of the EPA science panel, and the deregulation of carbon emissions “dangerous.”

Stansbury and Greene agreed on one thing: “We have one Earth,” they each said.

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

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2025. AGU. CC BY-NC-ND 3.0
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After a tropical cyclone passes through an area, governments take stock of the damage. NOAA, for instance, lists the costs associated with damaged buildings and roads and reports any injuries or deaths attributed to the storm.

“This research supports the historically overlooked indirect health risk and burden of tropical cyclones.”

However, research suggests that storms can also have hidden, long-term consequences for human health. In a new study published in Science Advances, scientists report that cyclones, also known as hurricanes and typhoons, produce a significant uptick in hospitalizations due to cardiovascular disease for months after they subside. In addition, the potential populations at risk for such hospitalizations are growing as a result of climate change intensifying cyclones and driving them into temperate regions such as Canada and New Zealand.

“This research supports the historically overlooked indirect health risk and burden of tropical cyclones and suggests the need for extending public health interventions and disaster preparedness beyond the immediate cyclone aftermath,” said Wenzhong Huang, an environmental epidemiologist at Monash University in Australia and the lead author of the new study.

Heart Problems Spike After Storms

Previous studies have examined possible connections between cardiovascular disease and cyclones, but most have focused on a single health center and storm in the United States.

“For our study, we encompassed multiple tropical cyclone events across decades and across multiple countries and territories with diverse socioeconomic contexts,” Huang said. “We also analyzed much longer post cyclone periods.”

“I didn’t expect that the risk would persist that long.”

The researchers tracked cardiovascular disease–related hospitalizations of more than 6.5 million people across Canada, New Zealand, South Korea, Taiwan, Thailand, and Vietnam from 2000 to 2019. They identified 179 locations that experienced cyclones and documented how many days storms hit each area. The team then examined hospital records to see whether more people were admitted for heart problems after cyclones, tracking patients for up to a year after each storm.

The results revealed that hospitalizations associated with heart health jumped 13% for every additional day a location was hit by a cyclone. The biggest spike in hospitalizations didn’t occur immediately after the cyclones but, rather, came 2 months after they passed, and the increased risk of hospitalizations didn’t subside until 6 months later.

“I didn’t expect that the risk would persist that long,” Huang said.

The health burden also fell unevenly across populations. Men, people in their 20s through 50s, and those in disadvantaged communities had the highest risk. In fact, cardiovascular risks after cyclones fell during the study period in wealthier areas while rising in poorer areas. This result suggests that improved health care access and disaster preparedness have benefited only some populations, with Thailand and Vietnam seeing the most cyclone-related heart problems. In total, strokes and ischemic heart disease (in which blood vessels supplying the heart are narrowed) were the most common maladies reported.

“There is not a single disease that’s not touched upon by hurricanes.”

Naresh Kumar, an environmental health scientist at the University of Miami who studies the health effects of cyclones but was not involved in the new study, was not surprised by the findings. According to his own extensive research on hurricanes in Florida and Puerto Rico, “there is not a single disease that’s not touched upon by hurricanes,” Kumar said.

But he would have liked the authors of the new study to narrow down the mechanisms driving up cardiovascular health risk after cyclones. The possible causes are abundant. In the months following a cyclone, people increase their use of generators, which produce pollutants; eat more calorie-dense canned foods; can’t exercise or access prescription medicines as easily; and are under immense psychological stress—all of which can increase the risk of cardiovascular disease. Meanwhile, regular health care services are often disrupted, so preventative care is limited.

Understanding these mechanisms is critical because current disaster response systems vastly underestimate the health burden of tropical storms, researchers say. “We are still scratching the surface in terms of characterizing the health effects of hurricanes,” Kumar said.

Huang said untangling the most significant contributors to increased risk following a cyclone is the next phase of his research. “I want to understand and investigate the candidates underlying this risk pattern,” he said.

As part of this process, Huang also aims to identify the reasons behind the elevated risk in some populations, such as working-age men. The research could help public health officials target interventions to high-risk populations and monitor cardiovascular health in the months following cyclones.

The Worsening Exposure to Storms

Answering the question of why more people suffer from heart problems after cyclones is becoming increasingly important to policymakers as more communities come under threat. Warmer oceans are fueling more intense storms with higher wind speeds and longer durations, while rising sea levels worsen storm surge flooding that can prolong recovery.

Climate change is also pushing tropical cyclones poleward into regions that have historically experienced few severe storms, such as eastern Canada and New Zealand. “Places that historically experienced fewer cyclone events could have much higher risk,” Huang said, suggesting such regions may be inadequately equipped to respond to major storms. “We need to focus on these regions to better prepare for the growing risk.”

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

Citation: Chapman, A. (2025), Cyclones affect heart health for months after they subside, Eos, 106, https://doi.org/10.1029/2025EO250342. Published on 16 September 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.

It’s been nearly 2 centuries since a planet was discovered in the solar system. But now scientists think they’ve uncovered evidence of a newcomer that just might usurp that honor from Neptune. Following an analysis of the orbits of bodies in the Kuiper Belt, a team has proposed that an unseen planet at least 25 times more massive than Pluto might reside there. These results were published in Monthly Notices of the Royal Astronomical Society.

The Kuiper Belt is loosely defined as a doughnut-shaped swath of space beginning just beyond the orbit of Neptune and extending to roughly 1,000 times the Earth-Sun distance. It’s home to untold numbers of icy, rocky objects, including Pluto and other so-called Kuiper Belt objects such as Arrokoth.

Everything in the Kuiper Belt can be thought of as cosmic debris, said Amir Siraj, an astrophysicist at Princeton University and lead author of the new paper. “It represents some of the leftovers from the formation of our solar system.”

And most of those leftovers are small: Pluto is the most massive known Kuiper Belt object, and it’s just 0.2% the mass of Earth.

But over the past decade, scientists have hypothesized that something substantially larger than Pluto might be lurking in the Kuiper Belt. Evidence of that unseen world—a so-called Planet Nine or Planet X—lies in the fact that six Kuiper Belt objects share curiously similar orbital parameters and are associated in physical space. A nearby, larger planet could have shepherded those worlds into alignment, researchers have proposed.

Planes, Planes, Everywhere

Siraj and his colleagues recently took a different tack to look for a massive resident of the Kuiper Belt: They analyzed a much larger sample of Kuiper Belt objects and focused on their orbital planes. One would naively expect the average orbital plane of Kuiper Belt objects to be the same as the average orbital plane of the planets in the solar system, said Siraj. But a planet-mass body in the Kuiper Belt would exert a strong enough gravitational tug on its neighboring Kuiper Belt objects to measurably alter the average orbital plane of the Kuiper Belt, at least in the vicinity of the planet. Siraj and his collaborators set out to see whether they could spot such a signal.

“Neptune has a really strong grasp on the outer solar system.”

The researchers extracted information about the orbits of more than 150 Kuiper Belt objects from the JPL Small-Body Database managed by NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Of the several thousand known Kuiper Belt objects, the team honed in on that subset because those objects aren’t gravitationally influenced by Neptune. Neptune is the playground bully of the outer solar system, and the orbits of many Kuiper Belt objects are believed to be literally shoved around by gravitational interactions with the ice giant. “Neptune has a really strong grasp on the outer solar system,” said Siraj.

The team calculated the average orbital plane of their sample of Kuiper Belt objects. At distances of 50 to 80 times the Earth-Sun distance, they recovered a plane consistent with that of the inner solar system. But farther out, at distances between 80 and 200 times the Earth-Sun distance, the researchers found that their sample of Kuiper Belt objects formed a plane that was warped relative to that of the inner solar system. There was only a roughly 4% probability that that signal was spurious, they calculated.

Meet Planet Y

Siraj and his collaborators then modeled how planets of different masses at various orbital distances from the Sun would affect a simulated set of Kuiper Belt objects. “We tried all sorts of planets,” said Siraj.

By comparing those model results with the observational data, the researchers deduced that a planet 25–450 times more massive than Pluto with a semimajor axis in the range of 100–200 times the Earth-Sun distance was the most likely culprit. There’s a fair bit of uncertainty in those numbers, but the team’s results make sense, said Kat Volk, a planetary scientist at the Planetary Science Institute in Tucson, Ariz., not involved in the research. “They did a pretty good job of bracketing what kind of object could be causing this signal.”

To differentiate their putative planet from Planet X, Siraj and his colleagues suggested a new name: Planet Y. It’s important to note that these two worlds, if they even exist, aren’t one and the same, said Siraj. “Planet X refers to a distant, high-mass planet, while Planet Y denotes a closer-in, lower-mass planet.”

“This is really expected to be a game changer for research on the outer solar system.”

There’s hope that Planet Y will soon get its close-up. The Legacy Survey of Space and Time (LSST)—a 10-year survey of the night sky that will be conducted by the Vera C. Rubin Observatory in Chile beginning as soon as this fall—will be supremely good at detecting Kuiper Belt objects, said Volk, who is a member of the LSST Solar System Science Collaboration. “We’re going to be increasing the number of known objects by something like a factor of 5–10.”

It’s entirely possible that Planet Y itself could be spotted, said Volk. But even if it isn’t, simply observing so many more Kuiper Belt objects will better reveal the average orbital plane of the Kuiper Belt. That will, in turn, shed light on whether it’s necessary to invoke Planet Y at all.

Even if his team’s hypothesis is proven wrong, Siraj says he’s looking forward to the start of the LSST and its firehose of astronomical data. “This is really expected to be a game changer for research on the outer solar system.”

—Katherine Kornei (@KatherineKornei), Science Writer

Citation: Kornei, K. (2025), A survey of the Kuiper Belt hints at an unseen planet, Eos, 106, https://doi.org/10.1029/2025EO250344. Published on 16 September 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.

This is an authorized translation of an Eos article. Esta es una traducción al español autorizada de un artículo de Eos.

Gale Sinatra y su esposo huyeron de su casa en Altadena, California, el 7 de enero con poco más que sus maletas, llevándose solo uno de sus dos autos.

“Pensábamos que íbamos a estar fuera por esa noche”, dijo Sinatra. “Pensábamos que controlarían el incendio y que volveríamos a entrar”.

Cuando la pareja regresó, semanas después, fue para excavar entre los escombros de su antigua casa, quemada por el incendio de Eaton.

Aunque escaparon con vida, los riesgos para la salud no fueron la excepción para Sinatra, su esposo (quien prefirió no ser identificado para esta historia) y otros vecinos. Los incendios de Eaton y el cercano Palisades llenaron la cuenca de Los Ángeles con una neblina tóxica durante días, y las labores de limpieza amenazaron con levantar partículas carbonizadas mucho después de que los incendios se extinguieran.

Equipos de científicos de todo el país, junto con miembros de la comunidad, monitorearon la calidad del aire en las semanas posteriores al incendio, buscando aprender más sobre los riesgos asociados a la salud respiratoria e informar a la comunidad sobre cómo protegerse.

Incendios urbanos versus incendios forestales

Inhalar humo de cualquier incendio puede ser perjudicial. El humo contiene componentes peligrosos, como compuestos orgánicos volátiles (COV) emitidos por la quema de vegetación y productos tales como pintura y productos de limpieza; y material particulado, como polvo y hollín.

Aproximadamente el 90 % del material particulado (PM) presente en el humo de los incendios forestales son las PM2.5, o partículas de menos de 2.5 micrómetros de diámetro, lo suficientemente pequeñas como para penetrar en el torrente sanguíneo y en las zonas profundas de los pulmones.

Michael Kleeman utiliza estos instrumentos para monitorear la calidad del aire desde la parte trasera de un vehículo en Victory Park, Altadena, lo más al norte posible sin entrar en la zona de evacuación. Crédito: Michael Kleeman

Los incendios forestales urbanos presentan sus propios peligros, ya que no solo queman árboles y otra vegetación, sino también viviendas e infraestructura.

Cuando Sinatra regresó a su antiguo hogar, quedó impactada por todo lo que el fuego había quemado, desde sus joyas hasta su coche. “Se me hizo muy inquietante estar en la cocina y de repente decir: ¿Dónde está mi refrigerador?”, comentó. “¿Cómo derrites totalmente refrigerador?”

En enero de 2025, los incendios de Palisades y Eaton devastaron más de 150 kilómetros cuadrados en ciudades y zonas forestales del condado de Los Ángeles. A pesar de verse afectados personalmente, los científicos del área de Los Ángeles trabajaron diligentemente para comprender cómo los incendios en la interfaz entre lo urbano y lo forestal crean peligros únicos a través del aire, la tierra y el agua.

En el futuro, las condiciones cálidas y secas, agravadas por el cambio climático, seguirán aumentando el riesgo de incendios como estos. El trabajo de estos científicos puede proporcionar un modelo para la evaluación rápida de riesgos, la mitigación de riesgos para la salud y la planificación urbana en otras comunidades propensas a incendios”.

“Desde colchones hasta alfombras, pintura y aparatos electrónicos, todo se quema”, afirmó Roya Bahreini, científica ambiental de la Universidad de California, Riverside (UCR). Bahreini también es coinvestigadora principal de la Red de Medición de la Química y la Ciencia Atmosférica (ASCENT, por sus siglas en inglés), un proyecto de monitoreo de la calidad del aire a largo plazo liderado por el Instituto de Tecnología de Georgia, UCR, y la Universidad de California, Davis (UC Davis).

ASCENT, que se lanzó en 2021, cuenta con estaciones en todo el país, incluyendo tres en el sur de California. Durante los incendios de enero en Los Ángeles, que arrasaron no solo Altadena (una comunidad no incorporada del interior) sino también barrios costeros, estas estaciones detectaron niveles de plomo, cloro y bromo en órdenes de magnitud superiores a lo habitual.

Las casas antiguas a veces tienen pintura con plomo, techos de asbesto o terrazas y cercas de madera tratadas con conservantes que contienen arsénico. Las tuberías de PVC contienen cloro. Y los retardantes de llama a menudo contienen compuestos orgánicos bromados. En estas formas, estos materiales no necesariamente representan un alto riesgo para la salud humana. Sin embargo, al quemarse y liberarse al aire, pueden ser peligrosos.

Las columnas de humo del incendio de Palisades (izquierda) y del incendio de Eaton se observan desde el espacio el 9 de enero. Crédito: ESA, contiene datos modificados de Copernicus Sentinel, CC BY-SA 3.0 IGO

Michael Kleeman, ingeniero civil y ambiental de la Universidad de California en Davis, explicó que la mortalidad a corto plazo asociada con eventos con altos niveles de PM2.5, como los incendios forestales, suele manifestarse en forma de un infarto cardíaco. Sin embargo, inhalar el humo de los incendios forestales urbanos o las partículas que se levantan del polvo y las cenizas durante las labores de remediación puede presentar riesgos que no son evidentes de inmediato. “No se trata de un infarto inmediato, al día siguiente o a los tres días de la exposición. Se trata de un riesgo de cáncer que aparece mucho más adelante”, señaló Kleeman. “[El riesgo a] la exposición a lago plazo puede tener un efecto insidioso”.

Mapas de calidad del aire

“[El riesgo a] la exposición a lago plazo puede tener un efecto insidioso”.

El sur de California no es ajeno a los incendios forestales (tampoco Sinatra, quien ha evacuado varias veces durante sus 15 años en Altadena). Las frecuentes sequías en la cuenca de Los Ángeles resultan en grandes extensiones de vegetación reseca. Los infames vientos de Santa Ana, que soplan en la cuenca desde el este y el noreste, pueden provocar que los incendios se descontrolen rápidamente, como ocurrió con los incendios de Palisades y Eaton.

Los mapas de calidad del aire en tiempo real, como los del Distrito de Gestión de la Calidad del Aire de la Costa Sur (AQMD, por sus siglas en inglés) y la EPA de EE. UU., se basan en diversas fuentes para proporcionar datos durante todo el año. Los datos más detallados provienen de sofisticados instrumentos instalados por las propias agencias; el AQMD de la Costa Sur alberga 32 estaciones permanentes de monitoreo del aire en los condados de Los Ángeles, Orange, Riverside y San Bernardino.

Datos menos detallados, pero más generalizados, sobre material particulado provienen de redes de herramientas de medición de la calidad del aire disponibles comercialmente, como los monitores PurpleAir y los sensores Clarity, instalados por residentes u organizaciones comunitarias.

El Distrito de Gestión de la Calidad del Aire cuenta con instalaciones permanentes para monitorear la calidad del aire, pero tras los incendios forestales de Los Ángeles de enero de 2025, implementó iniciativas complementarias, recopilando datos de calidad del aire en tiempo real desde camionetas móviles de monitoreo. Crédito: South Coast AQMD.

“Resulta que las zonas donde se produjeron los incendios contaban con [una] red muy densa de estos sensores de bajo costo”, afirmó Scott Epstein, gerente de planificación y normativa del South Coast AQMD. “Al combinar esto con nuestra red regulatoria, obtuvimos una excelente cobertura de la contaminación por partículas finas”.

Esta densidad permitió a los investigadores observar las columnas de humo de los incendios forestales de Eaton y Palisades a medida que se dirigían hacia la costa.

Una estación del AQMD en Compton, a unos 37 kilómetros (23 millas) al sur del incendio de Eaton, mostró niveles muy elevados de metales tóxicos, como arsénico y plomo, entre el 7 y el 11 de enero, mientras la columna pasaba sobre la zona. Estos niveles se normalizaron en pocos días. Los instrumentos ASCENT en Pico Rivera, a unos 23 kilómetros (14 millas) al sur del incendio de Eaton, registraron un aumento de 110 veces en los niveles de plomo entre el 8 y el 11 de enero.

Estaciones permanentes de medición de la calidad del aire como estas ofrecen una fuente de información pública que residentes como Sinatra pueden consultar para decidir cuándo quedarse en casa o regresar a una zona quemada. Sin embargo, cuando estallaron los incendios de Palisades y Eaton, investigadores del AQMD y otras instituciones se propusieron complementar estos esfuerzos con un monitoreo más detallado.

Movilizándose rápidamente Melissa Bumstead (izquierda) y Jeni Knack se ofrecieron como voluntarias para recolectar muestras de aire y cenizas tras los incendios de Eaton y Palisades. Crédito: Shelly Magier.

En enero, investigadores de la Universidad de Harvard; la Universidad de California, Los Ángeles (UCLA); la Universidad de Texas en Austin; la Universidad del Sur de California (USC); y UC Davis lanzaron el Estudio de Exposición Humana y Salud a Largo Plazo de Los Angeles Fire, o LA Fire HEALTH.

Mientras muchos residentes de Los Ángeles, incluyendo a Sinatra, seguían bajo órdenes de evacuación, los investigadores de LA Fire HEALTH se dirigían a zonas de evacuación.

Uno de estos investigadores fue Nicholas Spada, un científico especializado en aerosoles que viajó a Los Ángeles desde UC Davis el 14 de enero para instalar cuatro impactadores en cascada en Santa Mónica (cerca del incendio de Palisades), Pasadena (cerca del incendio de Eaton), Hollywood y West Hills. Estos instrumentos, del tamaño de un maletín, actúan como máquinas clasificadoras de monedas, explicó Spada: toman una muestra de aire y clasifican las partículas en ocho categorías de tamaño diferentes, desde 10 micrómetros (aproximadamente 1/9 del grosor promedio de un cabello humano) hasta 90 nanómetros (aproximadamente 1/1000 del grosor de un cabello humano). Los instrumentos recogieron ocho muestras cada dos horas hasta el 10 de febrero.

El instrumento “capta los cambios en las columnas de humo a medida que el incendio progresa de activo a latente y luego a extinto para después seguircon los efectos de mitigación”.

Un impactador en cascada permite a los científicos “asociar los perfiles de tamaño de las partículas con el tiempo”, explicó Spada. El instrumento “capta los cambios en las columnas de humo a medida que el incendio progresa de activo a latente y luego a extinto para después seguircon los efectos de mitigación”.

Las mediciones mostraron que no solo había elementos tóxicos como el plomo y el arsénico presentes en el aire durante todo el período de muestreo, sino que también una alta proporción de su masa (alrededor del 25 %) se encontraba en forma de partículas ultrafinas (del orden de nanómetros). Estas partículas no son filtradas por las mascarillas N95 y pueden penetrar profundamente en el cuerpo al inhalarse, explicó Spada.

Un equipo de investigadores de la Universidad de Texas llegó en una camioneta que también funcionaba como laboratorio móvil el 2 de febrero. Para entonces, los incendios ya estaban extinguidos, pero ya habían comenzado las labores de remediación que causaban la acumulación de polvo. Descubrieron que la calidad del aire exterior en las semanas posteriores a los incendios había recuperado los niveles previos y se ajustaba a las directrices de la EPA. Las muestras de interiores, especialmente las de viviendas dentro de las zonas quemadas, mostraron niveles más altos de COVs en comparación con las muestras de exteriores.

Los vecinos tienden una mano

Los miembros de la comunidad se sumaron a los esfuerzos para monitorear la calidad del aire.

Los miembros de la comunidad del sur de California también se sumaron a los esfuerzos para monitorear la calidad del aire. Melissa Bumstead y Jeni Knack, codirectoras del Laboratorio de Campo de Padres Contra Santa Susana, trabajaron con investigadores para crear y distribuir folletos sobre las medidas adecuadas para el equipo de protección personal, así como un protocolo de auto muestreo para los residentes que desearan recolectar muestras de ceniza de sus propiedades.

Por aproximadamente dos veces a la semana, del 14 de enero al 19 de febrero, recolectaron muestras de aire y ceniza en Pasadena, Altadena, Santa Mónica, Topanga y Pacific Palisades, y luego las enviaron a laboratorios, incluido el de Spada, para su análisis. El arsénico en todas las muestras de ceniza y el plomo en aproximadamente un tercio de ellas superaron los niveles de detección regionales de la EPA. Spada señaló en sus comunicaciones a los residentes que estos niveles de detección se basan en lo que es seguro para la ingestión de un niño y son relativamente conservadores.

“Esto ayudará a las personas en la próxima iteración de incendios a saber qué hacer”, recordó Bumstead haberles dicho a los residentes en las zonas de muestreo.

Después de las cenizas Sinatra perdió su casa en Altadena en el incendio de Eaton de enero de 2025. Al regresar para excavar entre los escombros, recorrió chimenea tras chimenea sin ninguna casa. Crédito: Gale Sinatra

El próximo incendio, dijo Sinatra, es algo que la abruma mientras ella y sus vecinos consideran la posibilidad de reconstruir.

Cuando la lluvia finalmente llegó al sur de California el 26 de enero, ayudó a extinguir los incendios y a controlar el polvo acumulado durante las labores de remediación, reduciendo así el riesgo de inhalación de toxinas.

Aun así, esas toxinas también estaban presentes en el suelo y el agua. Cuando Sinatra y su esposo regresaron al lugar calcinado de su casa, tomaron todas las precauciones que habían escuchado en las noticias, la EPA, los líderes comunitarios y los vecinos: usaron respiradores, trajes de protección, gafas protectoras y dos pares de guantes cada uno para protegerse.

La preocupación por las posibles consecuencias a largo plazo del aire que ya habían respirado, así como del suelo bajo sus pies, persiste mientras esperan más datos.

“Todos creen que existe una probabilidad significativa de un incendio en el futuro”, dijo Sinatra. “Nos preguntamos si sería seguro vivir allí, considerando la calidad del suelo y del aire, y si volverá a ocurrir.”

—Emily Dieckman (@emfurd.bsky.social), Escritora Asociada.

This translation by Daniela Navarro-Pérez was made possible by a partnership with Planeteando and GeoLatinas. Esta traducción fue posible gracias a una asociación con Planeteando and GeoLatinas.

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

Deep learning’s (DL’s) promise and appeal is algorithmic amalgamation of all available data to achieve model generalization and prediction of complex systems. Thus, there is a need to design multivariate training and predictions tasks in order to identify all relevant connections between variables across different space and time scales.

Ouyang et al. [2025] propose a multi-task long-short-term memory (LSTM) neural network to predict time series of multiple hydrologic variables. In the application of the approach, by combining different variables in the prediction task and sharing information between them, improved physical consistency and accuracy is achieved. The authors demonstrate this in various prediction exercises of streamflow and evapotranspiration including conditions of data scarcity.

The study is a good example of how innovation within DL can realize the promise of generalizable hydrological models and predictions of complex systems in future. It also implicitly encourages hydrologists to expand their DL approaches for multi-tasking. After all, there is a plethora of data and computing resources available to achieve DL’s promise.

Citation: Ouyang, W., Gu, X., Ye, L., Liu, X., & Zhang, C. (2025). Exploring hydrological variable interconnections and enhancing predictions for data‐limited basins through multi‐task learning. Water Resources Research, 61, e2023WR036593. https://doi.org/10.1029/2023WR036593

—Stefan Kollet, Editor, Water Resources Research

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

Rising carbon dioxide (CO2) levels are known to raise temperatures in Earth’s atmosphere. But slow feedback processes, including heat storage in the ocean and changes in the carbon cycle, mean that sometimes, such temperature changes don’t manifest right away; it can take decades, or even millennia, for Earth to reach equilibrium.

However, different climate models generate vastly different estimates of when such an equilibrium will be reached. One reason for these differences is the “pattern effect,” or the way uneven sea surface temperature changes can create distinct ocean warming patterns that affect atmospheric circulation and thus cloud cover, precipitation, and heat transfer. This complex interplay of factors can increase or decrease warming and shape the climate’s sensitivity to greenhouse gases.

One way to help predict what long-term warming patterns might look like is to turn to the past. Unearthing patterns in paleoclimate data, especially from times when Earth experienced a warmer climate, can provide insight into future warming patterns. Zhang et al. analyzed 10 million years of sea surface temperature records to determine the relative warming of different ocean regions under rising CO2 levels.

The study used the Western Pacific Warm Pool, the planet’s largest and warmest surface water body, as a reference point, comparing its sea surface temperature data with those of 17 other ocean sites to establish a global warming pattern.

The researchers then compared the warming shown in these paleoclimate data with the results of several models that simulate warming on the basis of an abrupt quadrupling of CO2 compared to preindustrial levels. They found the paleoclimate data and modeled results showed similar millennia-scale warming patterns, especially at higher latitudes. When both were compared to the past 160 years of sea surface temperature measurements, however, there were some differences in warming patterns. Modern warming is still in a transient state, influenced by ocean heat uptake, whereas the paleopattern represents the full equilibrium response.

It will take thousands of years to reach a new equilibrium, the researchers note. The study suggests that compared to the current transient warming, future warming patterns will be stronger at middle and high latitudes, including the North Pacific, North Atlantic, and Southern oceans. This high-latitude warming will likely be stronger than previous estimates suggested, and it is more pronounced in millennial-level than in century-level projections. (AGU Advances, https://doi.org/10.1029/2025AV001719, 2025)

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

Citation: Owen, R. (2025), Paleoclimate patterns offer hints about future warming, Eos, 106, https://doi.org/10.1029/2025EO250336. Published on 15 September 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.

Over the course of millennia, insects, spiders, and other arthropods in tropical forests have evolved in response to natural weather cycles like the El Niño–Southern Oscillation (ENSO).

With climate change, however, these global-scale phenomena are strengthening and becoming more frequent, and arthropods are unable to adapt. In a new study published in Nature, researchers found evidence that El Niño events influenced by global warming are chipping away at the diversity and functions of arthropods in tropical forests around the world.

To understand the effect of ENSO on arthropods, researchers led by University of Hong Kong entomologist Adam Sharp extracted data from studies conducted in tropical forests that have not been commercially altered by human activity, such as Barro Colorado Island in Panama, Mount Wilhelm in Papua New Guinea, and Kibale National Park in Uganda. These datasets included samples on arthropod diversity collected for 48 different species from 35 sites.

Using that information, the researchers created a model that allowed them to identify long-term trends in the diversity of different arthropod families through El Niño events from the 1990s until 2020.

They found a general decline among all the orders they analyzed, which included spiders, beetles, butterflies, cockroaches, termites, and other bugs. The only exception was Diptera, an insect order that includes flies and mosquitoes. Diptera was the only order whose species demonstrated increasing population trends during ENSO events.

Using this model, researchers were able to predict future declines as well as document current trends. They found that the most significant losses of biodiversity would most likely be among spiders, bugs, and butterflies.

The scientists also created a separate model to identify the effects of El Niño on the ecological services provided by arthropods, such as pollination, soil health, and pest control. To do so, they gathered data from studies that measured the amount of tree litter in tropical forests and the amount of damage to plant leaves caused by herbivore arthropods.

“In the models of leaf herbivory, we saw a big decline in the amount of leaves consumed by arthropods after around the year 2000. And this correlated strongly with what we predicted for the diversity of arthropods which would probably inflict that damage,” said Sharp. The model coincided with a decline in beetles in particular, he noted.

Mismatched Life Cycles

“Every time there’s a strong El Niño event, some of that biodiversity is chipped away and it doesn’t have time to recover before the next El Niño event.”

Sharp said that both models, although designed independently, support the same conclusion: “It looks as if every time there’s a strong El Niño event, some of that biodiversity is chipped away and it doesn’t have time to recover before the next El Niño event.”

Oliverio Delgado-Carrillo, an entomologist at the Universidad Nacional Autónoma de México who did not participate in the new study, said Sharp’s findings make sense in light of his own research, which focuses on a pollinator bee species associated with Mexican pumpkin flowers.

Delgado-Carrillo contributed to a paper published earlier this year in Global Change Biology that addressed the effects of climate change on the relationship between plants and pollinators.

Delgado-Carrillo and other researchers found that in general, flowers are beginning to bloom earlier, causing a mismatch between the life cycles of pollinators and their food supply. The pumpkin flowers studied by Delgado-Carrillo, for instance, bloomed before bees emerged from the soil, limiting the time available for pollination.

Sharp agreed with Delgado-Carrillo that more severe ENSO events will most likely cause more of these temporal mismatches between arthropods and plants.

Both researchers said the consequences of the decline in arthropod diversity are hard to predict but will likely be severe and far-reaching. In addition to effects on crops that rely on pollinators, for example, scientists point out that soil health would plummet without cockroaches processing leaf litter and other organic materials that provide nutrients to tropical soils.

In addition, Delgado-Carrillo expressed concern that without insects to control their populations, some opportunistic plants benefiting from climate change might outcompete less resilient species. “Herbivores are functioning as a kind of control mechanism for all those plants that could become dominant and interfere with these ecosystem processes,” he explained.

Filling the Data Gaps

Finally, Sharp and Delgado-Carrillo agreed that more research about ENSO and arthropods in tropical forests is needed. Sharp emphasized the knowledge gap surrounding tropical Africa and Southeast Asia in particular.

Yves Basset, an entomologist from the Smithsonian Tropical Research Institute in Panama, works on what’s most likely the only long-term continuous monitoring program of arthropods in tropical Latin America. His team’s work was one of the main sources of information for Sharp’s study, although he did not directly participate in the research himself.

For Basset, financing more projects like his in all tropical forests around the world is vital for understanding the effects of human-induced climate change on arthropods, especially for cyclic events like ENSO.

—Roberto González (@perrobertogg.bsky.social), Science Writer

Citation: González, R. (2025), El Niño may be driving insect decline in the tropics, Eos, 106, https://doi.org/10.1029/2025EO250339. Published on 15 September 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: Earth and Space Science

The surface of the Moon hides a complex and varied geology underneath. To unravel the Moon’s rich geological history, we rely on geophysical data acquired over decades of lunar missions. However, processing and interpretation of the remotely acquired data is not straightforward. Hence, new and sophisticated methods of processing and analyzing data are needed to extract the information necessary to detect and define lunar subsurface structures.

Ai et al. [2025] apply a new method combining an edge-detection algorithm, noise reduction techniques, and 3D inversion with high resolution gravity data from the Gravity Recovery and Interior Laboratory (GRAIL). The new approach allows them to sharply define the location and shape of a negative gravity anomaly beneath the Aristarchus Crater (the brightest feature on the Moon, located in Oceanus Procellarum, or “Ocean of Storms”). It confirms a complex geological setting involving crustal relief, fracturing caused by the impactor that formed the crater, dilation, and uplift of a volcanic unit. This study is important because it demonstrates a new method that will be useful to other researchers working on the Moon, and it advances our knowledge of lunar geology.  

Density contrast between subsurface masses in the subsurface of Aristarchus Crater. The distinction between negative anomaly (blue) and positive anomaly areas emerges very clearly, representing different geological processes.  The panels on the right indicate the performance of the models. Credit: Ai et al. [2025], Figure 21

Citation: Ai, H., Huang, Q., Ekinci, Y. L., Alvandi, A., & Narayan, S. (2025). Robust edge detection for structural mapping beneath the Aristarchus Plateau on the Moon using gravity data. Earth and Space Science, 12, e2025EA004379. https://doi.org/10.1029/2025EA004379

—Graziella Caprarelli, Editor-in-Chief, Earth and Space Science

Text © 2025. The authors. CC BY-NC-ND 3.0
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body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

The EPA proposed today that approximately 8,000 polluting facilities, including oil refineries, power plants, and steel mills, should no longer be required to report their greenhouse gas emissions.

Since 2010, the Greenhouse Gas Reporting Program has required that such facilities—spanning several dozen categories—report their emissions of greenhouse gases, such as carbon dioxide, to the government. The data is made public each October. According to the EPA’s own website, as it appeared today, the data can be used to “identify opportunities to cut pollution, minimize wasted energy, and save money,” as well as to “develop common-sense climate policies.”

 
Related

•  Read the EPA Statement
• EPA will halt greenhouse gas reporting for big polluters
•  E.P.A. To Stop Collecting Emissions Data From Polluters
•  EPA says companies shouldn’t have to report planet-warming emissions
 

The EPA statement claimed that the reporting program “has no material impact on improving health and the environment.” EPA Administrator Lee Zeldin said in the statement that the program is “nothing more than bureaucratic red tape that does nothing to improve air quality.”

“Instead, it costs American businesses and manufacturing billions of dollars, driving up the cost of living, jeopardizing our nation’s prosperity and hurting American communities,” he said.

Environmental groups have pointed out that, without this data, regulations cannot be enacted to protect Americans from the harmful effects of greenhouse gas emissions and climate change.

“Some industries want to keep this secret so that the public can’t know who’s responsible and hold them to account,” David Doniger, a senior attorney at the Natural Resources Defense Council, told the Washington Post. “What the public doesn’t know, they can’t demand be regulated.”

The move is the latest of many moves by the Trump administration to reduce regulations surrounding greenhouse gas emissions and other environmental protections.

In June, for example, the EPA proposed repealing federal limits on power plant carbon emissions. In July, the agency proposed rescinding the 2009 Endangerment Finding, which found that greenhouse gas emissions threaten public health and welfare and has since underpinned the federal government’s efforts to mitigate climate change.

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

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