EOS

Runoff from deep mountain snowpacks is the primary source of much-needed water for arid to semiarid regions in the western United States as well as in many other parts of the world. Each year, water managers in these regions must balance their water budgets, which account for water gained, lost, and stored in the watersheds they oversee, affecting everything from water supply to agriculture to tourism to wildfire containment.

To do so, water managers primarily rely on established statistical models that predict the volume and timing of mountain runoff. However, the information available to feed these models comes mainly from a sparse network of snow-monitoring weather stations, as well as from snow cover maps derived from optical satellite imagery that provide information on snow extent but not on the amount of water stored in the snowpack.

Managers of some basins, typically those home to watersheds that serve major population centers and agricultural producers, can also fund efforts to collect airborne high-resolution remotely sensed snow depth and snow mass estimations (e.g., from the Airborne Snow Observatories). These data significantly improve runoff models and streamflow forecasting for local water management and dam operations. However, the significant cost of these airborne surveys prevents many jurisdictions from accessing these types of data.

Detailed satellite snow volume and mass observations could give more water managers access to more complete information.

Data collected by satellites are more cost-effective and more frequent relative to airborne surveys. Therefore, detailed satellite snow volume and mass observations could give more water managers access to more complete information. For over 3 decades, researchers have developed snow remote sensing methods, working toward a satellite mission capable of sensing snow volume and mass—typically measured by snow depth and snow water equivalent, or SWE—at high spatial and temporal resolutions. Progress has been made, but amid ongoing warming-driven snowpack losses [Hale et al., 2023], there is still no funded global snow-focused satellite mission.

One way forward may involve the use of interferometric synthetic aperture radar (InSAR) to map changes in snowpacks. InSAR is commonly used in the geosciences to explore fault activity and volcanism through measurements of ground surface deformation. But the technique has been difficult to apply to snow because repeat intervals and radar wavelengths of current InSAR satellite platforms were not designed with snow retrievals in mind.

However, recent results from NASA’s 2017–2023 SnowEx campaign and the capabilities of the NASA–Indian Space Research Organisation SAR (NISAR) satellite mission—launched in late July 2025—spotlight InSAR’s potential as a novel, spaceborne snow remote sensing approach with high spatial resolution and near-global coverage. If this method is fully realized, high-resolution snow volume and mass measurements may be freely available for critical snow-dominant basins around the planet, with the potential to drastically improve water management sustainability practices. Such a resource could also enable scientific investigation within remote and inaccessible basins.

The NASA–Indian Space Research Organisation SAR (NISAR) satellite mission recently launched from India, as shown in the image at left. At right, the deployed satellite is shown above the western coast of the United States in this artist’s illustration. Credit: left, ISRO; right, NASA/JPL-Caltech Measuring Snow with Radar

Numerous ground-based and airborne studies over the past 50 years have established that snow depth and snow mass can be calculated from the travel times of radar waves in snowpack. Radar signals span the microwave and radio wave portions of the electromagnetic spectrum and have much longer wavelengths than those used in optical imaging. Radar signals with wavelengths greater than 1 centimeter transmit through dry snowpacks, which contain no melted water, whereas wavelengths longer than 20 centimeters can penetrate both dry and wet snowpacks [e.g., Bradford et al., 2009]. However, spatial resolution and bandwidth limitations prevent direct measurements of signal travel times from space using conventional radar systems.

Synthetic aperture radar methods have found many applications for Earth observation, especially because radar signals pass through cloud cover and because they can be used at night.

On the other hand, SAR methods, which leverage the phase and amplitude of the returned radar signal, have found many applications for Earth observation, especially because radar signals pass through cloud cover and because they can be used at night. SAR uses Doppler effect principles to combine multiple overlapping radar observations from a wide-swath radar antenna to simulate a larger antenna aperture, enabling imaging at very high spatial resolution (<10 meters) and recording the amplitude and phase of backscattered radar signals. SAR methods using backscattered amplitudes or phases have been studied and developed for snow applications for more than 25 years [e.g., Shi and Dozier, 1997; Guneriussen et al., 2001].

InSAR detects the change in phase of radar signals between two SAR data acquisitions. Any snow accumulation between data acquisitions causes a phase change in backscattered signals because radar waves move slower in snowpack than in air. This change in radar phase represents a change in the signals’ travel times and can be used to estimate changes in SWE directly; together with an estimated snow density, it can also be used to estimate changes in snow depth (Figure 1) [Guneriussen et al., 2001].

Fig. 1. This illustration shows the interaction of a synthetic aperture radar (SAR) signal with a snow-free (left) and subsequently snow-covered (right) environment. The snow-covered illustration is representative of snowpacks up to a few meters deep. Accumulated snow causes the signal to refract and slow slightly, causing a delay in the time it takes the signal to return to the satellite, which can be used to estimate changes in snow water equivalent (SWE). For visual clarity, the respective paths of backscattered and forward-scattered signals are not shown.

Until recently, InSAR for snowpack detection saw little evaluation and development, primarily because in situ SWE observations, which are needed to validate the method, were not collected coincident with InSAR time series. Other factors included imprecise satellite orbital information that is problematic for processing InSAR data, the shortage of satellites sensing at longer wavelengths and their respective acquisition strategies, and the fact that SAR data were largely proprietary (these data have become accessible since the launch of Sentinel-1 in 2014).

Long periods of time between InSAR data acquisitions (e.g., several weeks to months) further complicate application of the method, because longer time intervals between observations result in less accurate or often unresolvable phase information. In addition, when large snow accumulations cause more than 360° of phase change in the backscattered signal, there is ambiguity in the resulting SWE and snow depth estimations.

Previous work has therefore shown that frequent and regular observations are required to measure sequential changes in phase and accurately detect changes in snowpack SWE (e.g., from accumulation, ablation, or redistribution) [Deeb et al., 2011]. To then estimate the total SWE of a snowpack, changes in SWE between sequential pairs of InSAR acquisitions must be added together (Figure 2), an approach recently demonstrated using InSAR data collected by Sentinel-1 every 6 days [Oveisgharan et al., 2024].

Fig. 2. SWE accumulation was measured during water year 2024 at the Grizzly Peak SNOTEL (snow telemetry) station in Colorado (left). SWE has been subsampled to 12-day intervals to illustrate how an SWE accumulation curve from NISAR might look. Background colors represent the studied feasibility of the L-band InSAR method throughout the snow season. The highest feasibility is expected for December through mid-April, when the snowpack is likely dry. Lower feasibility is expected during warmer months, when liquid water within the wetter snowpack absorbs the radar signal energy. As measured using InSAR, snow accumulation or ablation events cause phase changes (i.e., changes in the signal path length or travel time) in the detected signals. The plot at right provides an idealized and simplified example of what those phase changes (φsnow) might look like based on the SWE accumulation and ablation shown at left. SnowEx-UAVSAR Puts InSAR to the Test

NASA’s SnowEx campaign served as a testing ground for many of the leading snow remote sensing methodologies, including interferometric SAR (InSAR).

NASA’s SnowEx campaign served as a testing ground for many of the leading snow remote sensing methodologies, including InSAR. SnowEx partnered with the NASA Jet Propulsion Laboratory Uninhabited Aerial Vehicle SAR (UAVSAR) program to collect airborne InSAR imagery over SnowEx field sites during 2017, 2020, and 2021 (Figure 3). (The UAVSAR was originally intended to fly on an autonomous aircraft, hence its name, but is instead flown in a piloted aircraft.)

Fig. 3. Data collection sites were located across the U.S. West. Each labeled site saw at least one pair of Uninhabited Aerial Vehicle SAR (UAVSAR) flights (white boxes). Locations of sites with ground-based radar measurements and SNOTEL/CDEC (California Data Exchange Center) stations, which provided complementary ground-based data, are indicated by red markers and pink dots, respectively. Credit: 2020–2021 NASA SnowEx Experimental Plan

The UAVSAR aircraft flies at about 12-kilometer altitude, carrying a SAR instrument that emits signals over an approximately 15-kilometer swath width, with a spatial resolution of about 5 meters and a wavelength of about 24 centimeters, which is within the L-band radar wavelength range. L-band radar waves are long enough to penetrate deep snowpacks (with minimal scattering in the snowpack) and some forest canopies, with the trade-off that the longer wavelength reduces sensitivity for mapping small snow accumulations or small wind redistribution events.

In February 2017, NASA SnowEx conducted airborne and ground campaigns, including UAVSAR flights, at sites in Grand Mesa and in Senator Beck Basin in western Colorado. The UAVSAR instrument was flown over each site on five dates from February to March. Direct evaluation of the repeat-pass L-band InSAR approach was not possible because the field campaign strategy was designed for evaluating other remote sensing methods. Still, the phase-change measurements were valuable for predicting snow depths with a machine learning algorithm, because the measured changes in SWE had a very similar spatial pattern to the total measured snow depth [Alabi et al., 2025].

On the basis of these early results, UAVSAR flew at weekly to biweekly intervals from January through March of 2020 and 2021 over 13 field sites in the mountains of the western United States and one site in Montana’s prairies. Accompanying ground campaigns emphasized repeat observations at specific locations to better evaluate InSAR measurements of SWE and snow depth changes. At each site, researchers collected a unique set of ground observations. At some, for example, they emphasized snow pit and snow depth collections, whereas at others the focus was on ground-based radar collections. To provide a more spatially expansive dataset for InSAR evaluation, airborne lidar snow depths were also collected at select sites.

These studies also demonstrated the utility of InSAR for mapping snowpacks over a variety of landscapes.

Four UAVSAR studies were conducted in mountain ranges with continental climates (characterized by hot summers and cold winters), where snowpacks are relatively shallow. At Grand Mesa, Colorado, InSAR snow depth and SWE change measurements were evaluated against spatially distributed airborne lidar snowpack measurements. Marshall et al. [2021] showed that InSAR snow measurements can be remarkably accurate in flat terrain and dry snow conditions.

Studies over 3-month periods in the mountains of northern Colorado further support the accuracy of InSAR-based findings, particularly during the accumulation season when snowpacks are dry [Bonnell et al., 2024a, 2024b]. These studies also demonstrated the utility of InSAR for mapping snowpacks over a variety of landscapes, including densely vegetated wetland meadows, severely burned forest stands, steep topography, and coniferous forests with low to moderate forest coverage.

A study in the Valles Caldera of New Mexico used InSAR to map snow accumulation and ablation early in the snowmelt season and found that the ablation patterns resembled snow losses observed in coincident optical imagery [Tarricone et al., 2023]. Until this study, measuring SWE with InSAR during this part of the snow season was considered infeasible because it was thought that wet snow would absorb and attenuate the radar signal too much.

Another two studies evaluated the InSAR method for snowpacks in the mountains of Idaho and in a Montana prairie. Idaho’s mountain snowpacks are classified as intermountain, which means they are generally deeper than continental snowpacks but shallower than maritime snowpacks (e.g., in California’s Sierra Nevada). Compared with continental mountain ranges, the intermountain climate regime also tends to be warmer, so midwinter snowmelt events are more common, though the snowpack remains colder and drier than maritime snow for much of the winter. The UAVSAR study in Idaho showed that L-band InSAR estimates generally agreed with manual SWE measurements and modeled SWE estimates at higher elevations. However, at lower elevations, InSAR SWE measurements had larger uncertainties where wet snow was identified [Hoppinen et al., 2024].

Prairie snowpacks, including those in Montana, can be intermittent, with winds scouring away snow in some areas and redistributing it into deep snowdrifts elsewhere. Palomaki and Sproles [2023] found that InSAR snow measurements had increased uncertainty where the ground was only partly covered by snow.

From SnowEx to NISAR

The NASA SnowEx campaign has enabled significant advances in developing a remotely sensed InSAR approach for measuring snowpacks. However, more work is needed to determine the approach’s suitability across environments, and it is not expected to work everywhere in all snow conditions. The presence of liquid water within snowpack is the biggest inhibiting factor, so it is uncertain how well L-band InSAR can handle wet maritime snowpacks, regions that accumulate snow near its melting point, and the spring snowmelt period. Although the method appears to work with high accuracy in some forests, it also remains to be seen whether it can be adapted for high-density forests.

Through these NASA SnowEx InSAR studies, the method appears successful for estimating SWE in areas covered by dry snowpacks that persist throughout the winter. Thus, it has applications in many critical snow-dominated basins. If widely applied, it could dramatically expand our understanding of seasonal snow dynamics around the world and aid prediction of melt season streamflow.

The NISAR satellite mission has attributes that could help achieve the goal of applying InSAR for snow water resources globally.

The NISAR satellite mission has attributes that could help achieve the goal of applying InSAR for snow water resources globally. First, like UAVSAR, NISAR will use an L-band radar signal, potentially allowing for accurate observations of phase changes over some forested areas and from deep snowpacks. Second, NISAR will have an exact revisit period of 12 days. This period is longer than the 7-day revisit period often tested during the SnowEx campaign but should be short enough to produce high-quality SWE measurements across many snow climates. Third, the Alaska Satellite Facility, which will distribute NISAR data, will provide InSAR datasets at 80-meter resolution within 2 days of acquisition, timely enough for water management decisions.

Unfortunately, the method’s potential was not demonstrated until after the NISAR science plan was developed, so the mission’s science objectives do not include seasonal snow measurements and a standard snow product will not be released. Also, although the 2020–2021 SnowEx-UAVSAR studies served as a partial proof of concept for satellite InSAR snow monitoring, the higher imaging altitude of NISAR could raise additional complications that will need to be studied and addressed. For example, NISAR will have lower-resolution imaging capabilities than the airborne UAVSAR platform, and the higher imaging altitude will introduce additional atmospheric and ionospheric artifacts in the satellite observations, some of which the NISAR team will attempt to estimate and remove.

Despite these obstacles, the results of SnowEx and the availability of NISAR data (plus the upcoming launches of other L-band SAR satellites such as ROSE-L (Radar Observing System for Europe in L-band) and the development of SWE mapping methods using higher radar frequencies) show that modern radar techniques are lighting the path to the future of global snowpack monitoring. To progress on this path, cross-disciplinary collaborations involving snow researchers, radar experts, data scientists, and, importantly, local water managers must continue evaluating and harnessing InSAR’s potential to detect changing snowpacks and inform water management decisions that affect people and habitats around the world.

Acknowledgments

We thank the participants, coordinators, and site leaders of the NASA SnowEx campaign and the NASA UAVSAR team, particularly Yunling Lou and Yang Zheng. Much of this research culminated from collaborations in the NASA L-band InSAR Snow Working Group (2021 to present) and the open-science tools developed during the NASA SnowEx Hackweeks (2021–2023). In particular, we acknowledge the efforts of Zach Hoppinen, Ross Palomaki, Shadi Oveisgharan, Ibrahim Alabi, Dan McGrath, Ryan Webb, Kelly Elder, Eric Sproles, Rick Forster, and Anne Nolin. We also acknowledge InSAR tower-based and satellite-borne studies that were produced in tandem with the SnowEx campaigns by Jorge Ruiz and Juha Lemmetyinen. Finally, we thank John Hammond and John Fulton for their constructive feedback. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government.

References

Alabi, I. O., et al. (2025), Advancing terrestrial snow depth monitoring with machine learning and L-band InSAR data: A case study using NASA’s SnowEx 2017 data, Front. Remote Sens., 5, 1481848, https://doi.org/10.3389/frsen.2024.1481848.

Bonnell, R., et al. (2024a), L-band InSAR snow water equivalent retrieval uncertainty increases with forest cover fraction, Geophys. Res. Lett., 51(24), e2024GL111708, https://doi.org/10.1029/2024GL111708.

Bonnell, R., et al. (2024b), Evaluating L-band InSAR snow water equivalent retrievals with repeat ground-penetrating radar and terrestrial lidar surveys in northern Colorado, Cryosphere, 18(8), 3,765–3,785, https://doi.org/10.5194/tc-18-3765-2024.

Bradford, J. H., J. T. Harper, and J. Brown (2009), Complex dielectric permittivity measurements from ground-penetrating radar data to estimate snow liquid water content in the pendular regime, Water Resour. Res., 45(8), W08403, https://doi.org/10.1029/2008WR007341.

Deeb, E. J., R. R. Forster, and D. L. Kane (2011), Monitoring snowpack evolution using interferometric synthetic aperture radar on the North Slope of Alaska, USA, Int. J. Remote Sens., 32(14), 3,985–4,003, https://doi.org/10.1080/01431161003801351.

Guneriussen, T., et al. (2001), InSAR for estimation of changes in snow water equivalent of dry snow, IEEE Trans. Geosci. Remote Sens., 39(10), 2,101–2,108, https://doi.org/10.1109/36.957273.

Hale, K. E., et al. (2023), Recent decreases in snow water storage in western North America, Commun. Earth Environ., 4(1), 170, https://doi.org/10.1038/s43247-023-00751-3.

Hoppinen, Z., et al. (2024), Snow water equivalent retrieval over Idaho–Part 2: Using L-band UAVSAR repeat-pass interferometry, Cryosphere, 18, 575–592, https://doi.org/10.5194/tc-18-575-2024.

Marshall, H. P., et al. (2021), L-band InSAR depth retrieval during the NASA SnowEx 2020 campaign: Grand Mesa, Colorado, in 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, pp. 625–627, https://doi.org/10.1109/IGARSS47720.2021.9553852.

Oveisgharan, S., et al. (2024), Snow water equivalent retrieval over Idaho–Part 1: Using Sentinel-1 repeat-pass interferometry, Cryosphere, 18(2), 559–574, https://doi.org/10.5194/tc-18-559-2024.

Palomaki, R. T., and E. A. Sproles (2023), Assessment of L-band InSAR snow estimation techniques over a shallow, heterogeneous prairie snowpack, Remote Sens. Environ., 296, 113744, https://doi.org/10.1016/j.rse.2023.113744.

Shi, J., and J. Dozier (1997), Mapping seasonal snow with SIR-C/X-SAR in mountainous areas, Remote Sens. Environ., 59(2), 294–307, https://doi.org/10.1016/S0034-4257(96)00146-0.

Tarricone, J., et al. (2023), Estimating snow accumulation and ablation with L-band interferometric synthetic aperture radar (InSAR), Cryosphere, 17(5), 1,997–2,019, https://doi.org/10.5194/tc-17-1997-2023.

Author Information

Randall Bonnell (rbonnell@usgs.gov), U.S. Geological Survey, Denver, Colo.; Jack Tarricone, NASA Goddard Space Flight Center, Greenbelt, Md.; Hans-Peter Marshall, Boise State University, Boise, Idaho; Elias Deeb, U.S. Army Corps of Engineers, Hanover, N.H.; and Carrie Vuyovich, NASA Goddard Space Flight Center, Greenbelt, Md.

Citation: Bonnell, R., J. Tarricone, H.-P. Marshall, E. Deeb, and C. Vuyovich (2025), Satellite radar advances could transform global snow monitoring, Eos, 106, https://doi.org/10.1029/2025EO250476. Published on 24 December 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.

Women and gender minorities, especially in lower-income countries, generally bear a greater burden than men do with regard to the impacts of climate change. For example, women are more often responsible for hauling water in drought-stricken areas, more often the targets of weather- and climate-driven violence, and more likely to find their education discontinued so they can work inside or outside the home, fulfill domestic tasks, or be married off to alleviate the cost to their birth families.

But just because they bear the brunt of climate burdens does not necessarily mean that they are more likely to think that climate change is human driven.

A recent analysis, published in World Development, showed that in countries with lower gross domestic product (GDP), greater access to education increased the percentage of women and gender minorities who think that climate change is driven by human activity. What’s more, in low-income countries with greater civil liberties, including a free media, people of all genders were more likely to think that human activity drives climate change.

“Having better knowledge on climate change increases propensity to be more engaged and build more resilience against climate change.”

“We have significant gender gaps in climate literacy in the developing world,” said Marija Verner, a climate communication researcher at the Yale Program on Climate Change Communication in New Haven, Conn., and lead researcher on the study. “As countries are advancing both economically and democratically, these gender disparities in climate literacy, they shrink.”

“Having better knowledge on climate change increases propensity to be more engaged and build more resilience against climate change,” Verner said. “But it’s important to know that there are important gaps in foundational knowledge about climate change.”

Polling the World

Past research has shown that women and gender minorities generally express greater concern about climate change and its impacts and more readily recognize that climate change is driven by human activity.

However, most of this research has focused on women in high-income, developed countries with generally broad access to education. The lack of research in lower-income countries, especially those in the Global South, is due in part to the fact that research hubs are concentrated in higher-income countries, Verner said. What’s more, it’s typically easier to collect sociodemographic and opinion data in more developed areas than in less developed ones.

“This just speaks to our biases and access in academia.”

“This just speaks to our biases and access in academia,” Verner noted. However, “I’d say in the [past] 5 years or a decade or so, we’ve been getting more and more good public opinion data, especially about environmental attitudes or climate change, from the Global South.”

Verner and her team turned to social media to overcome these challenges. They developed a survey that asked people’s belief about the causes of climate change as well as demographic information about gender, age, education level, and how urbanized the area in which they live is. The team partnered with Meta to administer the survey to Facebook users in 103 lower-income countries and territories.

They received more than 92,000 responses, with an almost even split between men and women plus gender minorities and different age groups. Verner said that respondents skewed slightly toward those with more education and those living in urban environments, which is reflective of Facebook’s user base.

“It’s a trade-off,” she said, “because in this way, you can reach more people, it’s quicker, it’s more efficient, you have a bigger coverage.…But the con is that you are sacrificing an extent of representativeness.”

Gaps in Climate Literacy

People were asked “Assuming climate change is happening, do you think it is…” and were offered four options ranging from denial of climate change to some level of natural causation to acknowledgement of human causation.

The team found that countries with the smallest economies have the greatest gender gap in climate knowledge: More than 50% of men believed in anthropogenic climate change, while less than 40% of women and gender minorities did. This gender knowledge gap disappeared in higher-GDP countries, driven entirely by more women and gender minorities believing in anthropogenic climate change—men’s beliefs remained unchanged.

“When it comes to a well-established democracy that starts backsliding, oftentimes it starts with restricting media freedoms [and] academic freedoms.”

The researchers looked into potential causes for this trend and homed in on education level and metrics related to a country’s civil liberties, like the ability to choose a government, speak freely, and access free media.

The team’s data showed that for all genders, greater access to education and greater civil liberties increased a person’s belief in anthropogenic climate change. In more democratic countries and those with more educated populations, the climate knowledge gender gap disappeared or reversed, with more women than men believing in human-driven climate change.

The connection between democratic freedom, education, and climate literacy noted in this research could have broad implications, as political scholars have noted that many countries around the world have experienced democratic backsliding over the past 2 decades.

“When it comes to a well-established democracy that starts backsliding, oftentimes it starts with restricting media freedoms [and] academic freedoms,” Verner noted, pointing to both Hungary and the United States as examples. “You are getting less access to all sorts of things, including climate change knowledge.”

Making a Difference

“This paper provides a test and empirical evidence to support the importance of gender disparities in understanding about the anthropogenic causes of climate change in less developed country contexts,” said Jennifer Givens, an environmental sociologist at Utah State University in Logan who has studied the relationship between gender and climate literacy.

Givens, who was not involved in the new study, found its education finding to be useful “because as [the researchers] note, policies could be implemented to address this specifically, in addition to policies that target inequalities in education more generally.”

“Once women gain better understanding, will it lead to social change?”

Verner said that data like these could help international groups create education programs tailored for regions where the gender knowledge gap is particularly wide. Future work might seek to disaggregate the data and examine the gender gap country by country.

Data like these could be a useful starting point for policymakers and educators, but Givens questioned whether simply increasing women’s climate literacy would be enough to shift the needle, especially if they remain politically marginalized.

“Once women gain better understanding, will it lead to social change?” she asked. More research is needed, she said, to understand the effectiveness of potential climate awareness campaigns in lower-income and less democratic countries.

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

Citation: Cartier, K. M. S. (2025), Democracy and education increase women’s belief in climate change, Eos, 106, https://doi.org/10.1029/2025EO250485. Published on 23 December 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.

When the first salmon return to Oregon’s Coquille River in the spring, thousands of fish congregate, and an important ceremony for the Coquille Indian Tribe (CIT) unfolds.

“You come out and you welcome them,” said Jason Younker, former Coquille Indian Tribe chief and assistant vice president of sovereign government-to-government relations at the University of Oregon. Neighbors share the first salmon of the season, and fish bones are returned to the river. “We’re giving thanks. And if you give thanks regularly and with intent, then you’re less likely to abuse the resources that are there in front of you,” said Younker.

But the region’s salmon have not always been treated with such care. The CIT is intimately familiar with the history of both the Coquille River and the Coos Bay estuary, located roughly 24 kilometers (15 miles) to the north. In the 1800s, logging practices and grazing animals introduced by settlers wreaked havoc on the salmon population in the estuary. These historical accounts are backed by recent research from the University of Oregon conducted in collaboration with CIT members, which was presented on 16 December at AGU’s Annual Meeting 2025 in New Orleans.

The research began when scientists studying the area’s vegetation were discussing plants and fish over dinner with Younker. During the conversation, Younker shared the importance of salmon to the region and to settlement history. Tribal knowledge pointed to the idea that salmon do not merely pass through Coos Bay but also deliver nutrients such as nitrogen from the ocean to rivers and wetlands.

“The bells in my head started ringing,” said Katya Podkovyroff, a doctoral student studying biogeochemistry and paleoecology at the University of Oregon. “If I’m looking at vegetation, salmon periods of migration at different points in time would impact the plant communities.”

Of Salmon and Soil Soil cores gathered by researchers suggested that salmon likely play a key role in nutrient cycling in the Coos Bay estuary. Credit: Katya Podkovyroff

University of Oregon researchers teamed up with CIT members, including university faculty members Younker and Ashley Cordes, a professor of Indigenous media studies. Together the group proposed that the rapid decline in salmon had removed nutrients from the river that supported plants and other animals.

To test their hypothesis, the researchers extracted meter-long soil cores from dry ground near the waters of the estuary, providing a physical timeline of the land, with the oldest soil at the bottom and newest soil at the top. They looked at elemental indicators, such as carbon-to-nitrogen ratios, to understand how available nutrients fluctuated over time.

Preliminary results showed that sites with previous restoration efforts—such as the removal of dikes and the addition of trees to stabilize stream banks—had lower carbon-to-nitrogen ratios and higher nitrogen-15 levels, aligning with those found in areas with more salmon. The patterns indicated that when salmon were more abundant, they likely played a critical role in the river’s nutrient cycling.

“I think that when we talk about science, you have to talk about Indigenous science, Indigenous ways of knowing, too.”

There are limitations to using cores to learn about an area. Most notably, a soil core represents only one very specific spot and is unable to show how its chemical or biological contents arrived at that location. To help address this limitation, the researchers plan to conduct more testing of regional environmental DNA, which could provide further evidence of when and where salmon have lived in the area.

“That seems like a really interesting and unique way of using this kind of tool, to try to look back through time, through cores,” said Katharyn Boyer, a restoration ecologist at San Francisco State University who was not involved in the research.

The team hopes their work will inform future restoration efforts. Regardless of the outcome, though, the research will remain collaborative. “I think that when we talk about science, you have to talk about Indigenous science, Indigenous ways of knowing, too. They, too, can augment science,” said Younker. “I think that Indigenous ways of knowing complement a lot of the science that exists.”

—Stella Mayerhoff (@stellamayerhoff.bsky.social), Science Writer

Citation: Mayerhoff, S. (2025), Blending science and Indigenous Knowledge to tell an estuary’s story, Eos, 106, https://doi.org/10.1029/2025EO250484. Published on 23 December 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.

When it comes to landslides, some of our planet’s largest have occurred underwater. But out of sight shouldn’t mean out of mind—submarine landslides can be both damaging and dangerous.

Researchers have now mapped the Stad Slide, an underwater megaslide that occurred in the Norwegian Sea several hundred thousand years ago. Material raining out of ancient glaciers set the stage for this event, and an earthquake might have been the ultimate trigger, the team surmised. And with a smaller nearby landslide known to have created a significant tsunami, the hunt is on for evidence of the waves that the Stad Slide might have unleashed. These results were published in the Journal of Quaternary Science.

Follow the Chaos

In many places around the world, jumbled layers of sediment lurk beneath the seafloor.

“The next best thing is to map these deposits.”

Such sedimentary chaos is evidence of one or more ancient underwater landslides that occurred on a grand scale. Humans have never witnessed such an event, but these megaslides are apt to damage undersea infrastructure like communications cables and trigger tsunami, said Bridget Tiller, a geographer at Newcastle University in the United Kingdom. By studying what’s left behind, it’s possible to better understand these events and potentially prepare for similar ones in the future, she added. “The next best thing is to map these deposits.”

Tiller and her colleagues recently focused on the Stad Slide, which occurred off the coast of Norway roughly 400,000 years ago. It’s one of at least five landslides that took place in the region over the past 3 million years. But given its hidden nature—the deposits of the Stad Slide lie roughly 1 kilometer beneath the seafloor, which is, in turn, capped by several hundred meters of water—it was first identified just a decade ago. That earlier investigation mapped less than 5% of the Stad Slide’s deposits, however.

Contrasting Sediments

Tiller and her team have now mined observations that cover nearly the entirety of this Switzerland-sized megaslide. Those data were collected from 2014 to 2018 by TGS, a company that amasses geological and geophysical data for energy exploration. The observations are seismic reflection data, meaning that they were generated by launching sound waves downward from a ship-based platform and measuring how those waves were reflected.

These measurements reveal not only the properties of the seabed but also the nature of the sediment layers beneath the seafloor, said Tiller. “Any time there’s a change in the properties of the sediment below the seabed, you can see these different reflections.”

The researchers discovered interspersed layers of sediment, some measuring up to hundreds of meters thick. Those layers appeared to be composed of either coarse material or fine-grained, sand-dominated material. That layering of contrasting sediments likely predisposed the region to sloughing off in a landslide, the team concluded.

The coarser sediments probably built up over time as a result of ancient glacial activity in the region, the team surmised. Glaciers literally scrape the landscape, depositing sediments entrained within them, explained Rob McKay, a sedimentologist at the Antarctic Research Centre at Victoria University of Wellington in New Zealand not involved in the research. “They basically bulldoze a lot of sediment,” said McKay. “In some places, it can be meters per year of sediment coming out.”

The finer, sand-rich sediments naturally accumulated over the eons because of erosion, the researchers found. Those sediments could well contain biological material, added McKay, which might predispose their layers to sliding down the continental shelf. Aquatic microorganisms known as diatoms create slippery mats when they settle out of the water column, and McKay and his team have suggested that such layers could predispose a region to sliding. “That creates a slide plane,” said McKay.

But a trigger of some sort was probably likely to send those layers moving downslope, the researchers concluded. “It wouldn’t fail just on its own,” said Tiller. An earthquake is a likely culprit, the team noted. However, ground movement due to isostatic rebound might also have done it, said McKay.

Stairs Beneath the Seafloor

“We think it formed in multiple stages.”

Tiller and her collaborators inferred that the sediments that composed the Stad Slide failed in several stages. Finding multiple scarps in a kind of stair-step profile indicated that material had let loose sequentially, said Tiller. “We think it formed in multiple stages.”

The current dataset doesn’t reveal anything about how closely in time those failures might have occurred, however, said Tiller. “It could be almost instantaneous, it could be up to several hundred years apart.”

The team estimated that roughly 4,300 cubic kilometers of sediment were displaced by the Stad Slide. That’s roughly 1,000 times the volume of material ejected by the largest volcanic eruption of the 20th century, the team calculated. And all that material in motion would have displaced seawater, potentially resulting in a tsunami.

Another underwater landslide in the area, the much younger Storegga Slide, is known to have produced a tsunami whose waves reached more than 10 meters above sea level. The Stad Slide is about 30% larger by volume than the Storegga Slide, so it’s highly plausible that it too triggered a large tsunami. But finding evidence of waves from that long ago is a tall challenge, said Tiller. “It’s nearly half a million years ago now. It’s possible they wouldn’t have been preserved.”

But don’t give up yet, said McKay, because there’s good evidence for far older tsunamis. In New Zealand, unusual rock outcroppings originally attributed to tectonic activity are now believed to be due to the tsunami waves that rolled up on shorelines 65 million years ago following the dinosaur-killing asteroid impact marking the end of the Cretaceous.

—Katherine Kornei (@KatherineKornei), Science Writer

Citation: Kornei, K. (2025), New eyes on one of the planet’s largest submarine landslides, Eos, 106, https://doi.org/10.1029/2025EO250469. Published on 22 December 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 audio story from Eos, your trusted source for Earth and space science news. Do you like this feature? Let us know in the comments or at eos@agu.org.

TRANSCRIPT

Emily Gardner: Justin Higa is a geologist, a postdoctoral researcher at the University of Hawaiʻi at Mānoa, where he studies landslides.

But like most of us, he does more than just work. He has hobbies. When he was in high school, he started taking lessons on the sanshin, a three-string lute that has been called “the soul” of the music tradition in the Ryukyu Islands, a chain of southern Japanese islands that include Okinawa. Higa himself is Okinawan, and he wanted to learn more about his culture. So he joined the Ryukyu Koten Afuso Ryu Ongaku Kenkyu Choichi Kai USA, Hawaiʻi Chapter. His instructor was June Uyeunten, or, as he calls her, June Sensei.

At AGU’s Annual Meeting in New Orleans this December, Higa presented research that aimed to bridge the worlds of geoscience and Indigenous Ryukyuan music.

Justin Higa: This started because when I was an undergrad at the University of Hawaiʻi, there was a lot of focus on place-based science and Indigenous Knowledge and Hawaiian knowledge in geology. So because of this background in the arts that I had, and I knew that we’d sung songs about nature and animals and plants, I thought, “Oh, you know, we could do similar things with the songs that we sing and interpret science from lyrics.”

Gardner: Higa went to California for grad school, but when he came back to Hawaii for his postdoc, he had a little more freedom to pursue different research interests, and he was back in a place with a strong Okinawan diaspora presence. Maybe he could use this music to teach the public, and people interested in music, about the geosciences. His mentor, Uyeunten, was excited for the inverse reason: Maybe this could be a way to get the public, and scientists, interested in Ryukyuan music.

June Uyeunten: I got superexcited, cause I’m like, if Justin can get that excitement out into the public, maybe we can tap other people who are not interested in this type of music to learn more about it, right? And so you don’t know which audience we’re going to appeal to. And so we just have to try different ways to educate others. And music is universal. You don’t need to understand the lyrics, but you could feel it when a performer sings it, right? 

Gardner: Higa teamed up with Uyeunten and Kenton Odo, who are both instructors in the same chapter, to look at how Indigenous Ryukyuan music could be used to teach about geoscience and the climate.

They focused their analysis on a pair of sailing songs, both composed in the 18th century. One is called “Nubui Kuduchi”; Kuduchi is a subgenera of Ryukyuan classical music. And nubui means “climbing up.” The song starts with a description of a group of envoys walking from the Ryukyu capital to the main port on Okinawa, stopping at temples along the way to pray, and then saying goodbye to their families. Then, they set sail to the Kyushu islands:

 (sample of “Nubui Kuduchi” plays)

The lyrics here say, “Sailing across the rough seas off the coast of Iheya, we look out over the route of many islands. To see the Tokara Islands and Strait, and pass without mishap. How lucky we are.”

The south-southwesterly winds described in the song, taking place between May and September, match with observations from the 20th and 21st centuries, which have documented the same wind patterns at the same time of year. The researchers further looked at historical records, which showed that during this period of history, about 20 such envoy departures took place each year between approximately May and August. It all lined up perfectly.

They also analyzed another song called “Kudai Kuduchi.” Kudai means “climbing down.” In this song, the envoy returns to Okinawa island via north-northeasterly winds.

 (sample of “Kudai Kuduchi” plays)

The lyrics here say, “The winds are directly from the north-northeast, with Cape Sata behind us. Sailing comfortably over the seas of the Tokara Islands and Strait.”

Once again, it all lines up: The northeasterly boreal winter monsoon typically occurs from September to May, and historical records show the envoys returning to port at that time of year.

Higa: We could make implications and a discussion about how this kind of implies a reliance on a very constant monsoon season for travel, and when that breaks down, that’s a problem for them. 

Gardner: In another line, the sailors observe an active volcano.

Higa: It’s kind of cool in that this volcano that they observed as active during their boat journey, it was kind of in a location that’s a little outboard from the main Japanese islands that had a lot of written historical records.

So maybe the earliest record was from, I think the 12th century, and then we have our song from the 18th century and then modern instrumented science. So it’s these three points of volcanic activity and ours is kind of bridging that in the middle, kind of implying that, yeah, this volcano has been active for continuously for a very long time and that aligns with geochronologic dating, geologic mapping of this area.

Gardner: James Edwards is an ethnomusicologist at the SINUS Institute, an institution for market and social research in Germany. He wrote his dissertation on the Okinawan performing arts, tracking its development from the 17th century to today. He focuses in part on ecomusicology, a field that examines, among other things, how music mediates the relationships between humans and the environment.

Edwards was not involved in this work, but he said the project was really interesting and could be a launching point for potential interdisciplinary collaboration.

James Edwards: Traditional ecological knowledge can be a valuable intervention contra the overreach of Western scientism and the privileging of Western knowledge systems, right? In this case, you have the opposite. You have a traditional ecological system and Western scientific knowledge synergizing and complementing each other in a really beautiful way.

Gardner: On top of the research presented at AGU25, the authors have published a paper about their work in Geoscience Communication and shared the work in the science and art worlds, including at the Geological Society of America conference and an Okinawan festival in Hawaii. September of 2025 marked 125 years since the first Okinawan immigrants arrived in Hawaii. Especially during such a landmark year, Higa and Uyeunten have high hopes for the work. Incorporating such music into science lessons, for instance, could help educators demonstrate the value of Indigenous Knowledge throughout history.

Uyeunten: If you can blend your career with your culture and with some art form, I think that’ll just, you know, be a good thing to just broaden everyone’s lenses.

Higa: I guess it, I hope it really shows the legitimacy of Indigenous Knowledge from all cultures and it inspires other people to….think of themselves as you can be a scientist and you can be an artist.

Reading List

Paper in Geoscience Communication: Place-based science from Okinawa: 18th-century climate and geology recorded in Ryukyuan classical music

AGU25 abstract: Transforming Indigenous Ryukyuan Music into Geo- and Climate Science Lessons for the Ryukyuan-Okinawan Diaspora in Hawaiʻi

Ryukyu Koten Afuso Ryu Ongaku Kenkyu Choichi Kai USA

University of Hawaiʻi press release

(“Kudai Kuduchi” fades in)

Gardner: Thank you to Justin Higa and June Uyeunten for speaking with me and to their coauthor, Kenton A. Odo. All are members of Ryukyu Koten Afuso Ryu Ongaku Kenkyu Choichi Kai USA, Hawaiʻi Chapter. Thank you also to James Edwards for providing an outside perspective. Credits for the music are as follows:

Translation and interpretation: Hooge Ryu Hana Nuuzi no Kai Nakasone Dance Academy, Clarence T. Nakosone

Singing and Sanshin by Kenton Odo

Tēku (the drums) and fwansō (the bamboo flute) by June Uyeunten

Thanks for listening to this story from AGU’s Eos, your source for Earth and space science news. As always, you can find a transcript of this story, as well as links to the relevant research, at Eos.org.

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

Citation: Gardner, E. (2025), What Okinawan sailor songs might teach us about the climate, Eos, 106, https://doi.org/10.1029/2025EO250486. Published on 22 December 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.

Butterflies are often considered bellwether species for climate change, and to retain the cooler climates they need for their life cycles, species around the world have been shifting their habitats and migratory patterns to higher latitudes and higher elevations.

But are the plants that butterflies depend on shifting their habitats in step?

New research has found that out of 24 Southeast Asian butterflies examined, 17 of them (71%) could experience a net loss in the habitat area they share with their host plants under a high-emissions climate change scenario. Some butterfly species may lose nearly 40% of shared habitat as they retreat to cooler climes.

Losing Ground

Like most species on Earth, butterflies have a preferred temperature range. As climate change warms the planet, many butterfly species have shifted their habitats, typically moving to cooler, higher elevations or higher latitudes. But wherever they go, butterflies still need plants that provide food and host their larvae (caterpillars). Some butterflies depend on a single host species, while others can rely on several.

Plants, too, have environmental needs, but whether the insects and the plants they need are shifting their habitats at the same speeds and in the same direction has been unclear.

To compare shifting species ranges, researchers simulated how tropical Asian butterflies and their host plants would each experience habitat migration in response to a high-emissions climate change scenario (SSP585). They selected 24 butterfly species whose ranges span from dense lowland rainforests to mountainous highlands. Some species have large ranges, and others have small ranges. Some depend on a single host plant, and others can use several.

“We wanted to choose the most representative butterfly species in tropical Asia,” said Jin Chen, lead researcher on the project and a doctoral student at the University of Helsinki. “We only used climate data as the predictive factors. We wanted to see, in the worst situation, what happens to them.”

“I don’t think there’s any situation [in which] a butterfly will prefer to go a warmer place.”

They found that 17 of the 24 butterfly species would experience a net decoupling from their host plants, with shared habitat area decreasing between 6% and 39%. As expected, the decoupling in lowland areas was primarily driven by butterflies fleeing to cooler, higher-elevation areas.

“I don’t think there’s any situation [in which] a butterfly will prefer to go a warmer place,” Chen said.

But the model also predicted significant habitat decoupling in those cooler, higher-elevation regions, which was unexpected. The loss of shared highland habitat was primarily driven by the host plants not being able to thrive there, and as a result, the butterflies had no support system when they arrived. Butterfly species that are pickier about their plants experienced the biggest coupled habitat losses.

“The hot spots of this decoupling are mostly in the mountain regions of tropical Asia, including Borneo and the boundary of Laos, Vietnam, and Cambodia,” Chen said, as well as “the north of Myanmar close to the Himalayas.”

The model did predict that seven butterfly species would gain shared habitat with plants, with net gains of 1%–42%. Those gains were a result of several host plants expanding their ranges significantly in a warmer climate. The butterflies that relied on those plants had more options despite their own habitat shifts.

The team presented their results on 15 December at AGU’s Annual Meeting 2025 in New Orleans.

“There’s a lot of uncertainty in how butterflies are responding or will respond to climate change globally—and this is especially true in the tropics where data are generally sparse and species interactions complex,” said Timothy Bonebrake, a conservation scientist at the University of Hong Kong who was not involved with this research. “But yes, there is evidence that Asian species are shifting their distributions in response to warming and other environmental changes.”

“What role host plants play in such movements is less clear and needs further investigation,” he added. “So studies like this that model host and butterfly responses are a useful first step for understanding such impacts.”

Fluttering Away

“Modeling species interactions under global change can provide important perspectives for managers and conservation planners by emphasizing key linkages in the ecosystem,” Bonebrake said. “Indeed, for many butterfly species, host plant availability will be a key limiting factor that constrains distribution tracking. Research like this can help to identify which types of species might need attention or active intervention under rapid warming.”

Chen noted that because the team’s model used only climate change as a predictive factor, it might not have fully captured how plant ranges will change. Although temperature shifts, driven by climate change, are the most important factor for butterflies, plants also respond to land use changes, she said. Future modeling will include predicted land use change under different emissions scenarios and thus will provide more precise predictions about which butterfly species could thrive or falter.

“Hopefully, this ability will also give species an additional avenue for persisting in rapidly changing environments.”

Still, these initial models provide clues about which species are under more threat than others and can spark ideas about how humans can intervene to protect vulnerable pollinators. People living in cooler areas to which butterflies are fleeing can help support the insects by protecting their host plants from destructive land use and by planting more pollinator-friendly plants to support butterflies’ life cycles.

“We sometimes underestimate the ability of butterflies to switch host plants or otherwise alter their life histories to cope with climate change,” Bonebrake said. “When they do shift hosts, it introduces an additional element of complexity with respect to climate change projections. But hopefully, this ability will also give species an additional avenue for persisting in rapidly changing environments.”

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

Correction 19 December 2025: The photo caption has been corrected to identify the butterfly as Idea leuconoe, not Idea stolli.

Citation: Cartier, K. M. S. (2025), Climate change could drive butterflies and plants apart, Eos, 106, https://doi.org/10.1029/2025EO250481. Published on 19 December 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.

Source: AGU Advances

The low-latitude highlands region of southwestern China experienced two major climate events in recent years: a severe drought in 2009–2010 and an extreme heat wave in 2019. Though both sprang from similar large-scale atmospheric circulation patterns, the events produced different responses, raising questions about how multiple stressors can push ecosystems toward contrasting outcomes.

Southwestern China’s highlands system offered scientists a chance to study the ways a sensitive ecosystem reacted to both a once-in-a-century drought and an exceptional heat wave. Pan et al. analyzed soil moisture, vegetation productivity, and temperature using remote sensing data and nonlinear structural equation modeling. They discovered a distinct “personality switch” in the way the ecosystem responded to the second event versus the first.

In 2010, when drought left the soil very dry, the ecosystem’s productivity was limited by the amount of available water. During that drought, plant growth slowed as vegetation operated in survival mode and restricted water to its roots. In 2019, when the soil was moistened by previous rains, water was not a limiting factor. Instead, the hot temperatures served as an energy source and caused plant growth to thrive.

Wetter antecedent conditions helped the ecosystem better weather the heat, the research showed. This concept of “hydrological memory” helps explain why the ecosystem reacted so differently to two extreme events. Such a nonlinear effect can be hard to capture in traditional modeling, so these findings have important implications for future modeling and climate change projections, the authors say. Untangling seemingly unpredictable ecosystem behaviors, they continue, could help improve understanding of our planet and its future. (AGU Advances, https://doi.org/10.1029/2025AV001973, 2025)

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

Citation: Owen, R. (2025), An ecosystem never forgets, Eos, 106, https://doi.org/10.1029/2025EO250472. Published on 19 December 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.

Source: Journal of Advances in Modeling Earth Systems (JAMES)

An existing body of research indicates that climate change is making tropical cyclones wetter and more powerful.

Now, new research is indicating the same thing may be happening to the precursors of these storms: the wet weather systems that sometimes give rise to destructive hurricanes and often cause hazardous rain and flooding.

Tropical cyclones don’t spring into existence fully formed. Around 85% of Atlantic hurricanes, for instance, originate from African easterly waves, westward-moving disturbances of low pressure over Africa in which warm, humid air rises into the atmosphere from below and forms rain clouds. Despite these weather systems’ critical role as “seeds” for tropical cyclones, however, it’s not fully understood how climate change may affect their development.

Núñez Ocasio et al. recently investigated how African easterly waves might behave differently in the future because of climate change. To do this, Núñez Ocasio first developed a new regional weather model configuration that allowed for more realistic representation of possible rainfall extremes. Using this improved model, the team focused on the formation period of the wave that would become 2006’s Hurricane Helene and simulated how the storm might have played out differently in a warmer, more humid environment.

Under a scenario of high greenhouse gas emissions, the researchers found that by the end of the century, waves like the one that became Helene will grow significantly more intense, spinning faster and holding a greater amount of water vapor relative to their surroundings. At the same time, the waves will travel more slowly across Africa. Altogether, this means they will linger for longer periods while dumping heavier rain over affected areas, exacerbating the risk of extreme flooding.

Given that risk, the authors call for the use of high-resolution models like those in the present study to further research how African easterly waves will respond to climate change. Such studies may provide vulnerable communities with the information they need to prepare for extreme weather.

The authors also note that although forecasts with short lead times—the time between a weather forecast and the actual weather event—tend to offer higher accuracy, longer lead times may better account for the slower movement of future African easterly waves. (Journal of Advances in Modeling Earth Systems (JAMES), https://doi.org/10.1029/2025MS005146, 2025)

—Sean Cummings, Science Writer

Citation: Cummings, S. (2025), Warming may make tropical cyclone “seeds” riskier for Africa, Eos, 106, https://doi.org/10.1029/2025EO250468. Published on 19 December 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 that impacts science and scientists today.

Images and audio samples of an eight-foot tall resin sculpture created by singer and artist Jewel, emitting a soundscape informed by ocean data from NASA, were shown at AGU’s annual meeting in New Orleans on 16 December.

“The entire sculpture is entirely data,” Jewel said at a press event where she discussed the piece’s development. Jewel was joined by Chelle Gentemann, program scientist at NASA’s Office of the Chief Science Data Officer, and Kevin Murphy, NASA’s Chief Science Data Officer.

The sculpture and soundscape, together named Heart of the Ocean, will debut at the Venice Biennale in 2026 along with other works by Jewel.

Jewel worked closely with NASA to select data that would translate well into an art piece. The soundscape is constructed with tones, sounds, and a tempo informed by open-source NASA data on the Atlantic Ocean’s wave height, precipitation, salinity, currents, seismicity, and wildlife. Datapoints are translated into a “sound library” created by Jewel that then comes together to form music.

The soundscape “travels” to the deep ocean, slowing as ocean temperatures drop. Then, the piece quickens, and “ascends” to convey ocean surface data. Cloud cover and ocean current data inform how the soundscape moves from one ear to another, simulating a 3-dimensional experience.

 
Related Content

• From Data to Wonder: Transforming NASA Data into Art
•  Singer-Songwriter Jewel blends ocean science and sound in data-inspired soundscape

“I learned so much,” working with NASA, Jewel said. “It was an incredible intellectual exercise to take that data and not want to alter it,” but still transform it into meaningful music. “I felt I had to be really honest about the data … I wanted it to be pure. I wanted it to be nature, talking to you,” she said.

The soundscape changes in accordance with near real-time Atlantic Ocean conditions, as the data update every 12 minutes. “If it’s raining, the piece looks and sounds different. If it’s stormy, the piece is different. It’s a living instrument that the ocean gets to play in real time,” Jewel said. She particularly likes to experience the piece under full moon conditions.

Jewel hopes the piece raises awareness about the accessibility of NASA data. “It was only because of open data” that she was able to build the piece, she said. 

Gentemann, the NASA program scientist, said the experience was a valued opportunity to explore the artistic side of an otherwise very technically focused career.  

When asked for advice to scientists looking to collaborate with artists, Jewel said: “If there’s an artist that you’re inspired by or a storyteller that you’re inspired by, just reach out.”

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

These updates are made possible through information from the scientific community. Do you have a story about science or scientists? Send us a tip at eos@agu.org. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

The future of the Amazon may rely on its past. According to new research, landscape interventions made by the forest’s pre-Columbian Indigenous inhabitants might still affect the forest’s ecological functions, including its capacity to store biomass, absorb carbon, and withstand climate change.

For centuries, academics believed that the Amazon forest’s poor soil and harsh environment were unsuitable for supporting large and complex prehistoric societies. Before the arrival of Europeans, it was thought, the Amazon was mostly untouched, occupied only by small, nomadic Indigenous groups.

But recent archaeological research, aided by remote sensing technologies such as satellites and lidar, has challenged this idea, revealing extensive pre-Columbian settlements and land modifications throughout the forest. The new findings support the view that Indigenous peoples have actively shaped the forest’s landscape for at least 13,000 years.

Landscape interventions by these early inhabitants included selectively planting and domesticating large forest areas, as well as creating fertile soils known as terra preta, or Amazonian dark earth, by composting organic matter. Some groups even built extensive settlements that left ground marks like mounds and ditches, called earthworks, which are still visible from the sky via satellite and lidar.

In 2023, geographer and remote sensing expert Vinicius Peripato from Brazil’s National Institute for Space Research (INPE) and other researchers published a paper in Science that used lidar and mathematical models to estimate that as many as 24,000 pre-Columbian earthworks could still be hidden beneath the forest’s tree canopies.

Now, Peripato and colleagues have expanded their research to better understand the ecological effects of such large-scale land modifications by ancient forest inhabitants. In a study presented on 18 December at AGU’s Annual Meeting 2025, they used satellite and lidar imagery, along with mathematical models, to compare biomass levels both in areas of the forest where these pre-Columbian modifications were likely to be present and in places where they were not.

A forest reflects different wavelengths of light depending on the structure, density, and height of its vegetation. This property allows researchers to roughly calculate biomass levels in a forest, along with the amount of carbon the forest stores. To refine these estimates, the scientists also used vegetation maps, topographic models, and forest inventory data, providing a global picture of how much biomass the forest stores in 100-meter grids.

Researchers used lidar to image earthworks in Rio Branco in the Brazilian Amazon. From top to bottom, the layers represent the lidar point cloud colored by its height, followed by the terrain slope, hillshade, and elevation of an earthwork, all obtained after the digital removal of the forest. Credit: Vinicius Peripato A More Resilient Forest

Using this combination of methods, the researchers compared the biomass levels in dry and wet parts of the forest from 2010 to 2020. They discovered that within both dry and wet areas, areas with evidence of pre-Columbian management (or areas likely to have had such management based on their predictive models) contained significantly more biomass than untouched regions.

This was true even during extreme weather events, especially in dry areas. In 2010 and 2020, both years marked by severe droughts, researchers found that while the regional biomass average ranged from approximately 65 to 240 megatons per hectare in dry areas, managed portions of the forest in the same regions contained from 70 to 300 megatons of biomass per hectare—about 15%–22% above the regional average.

“The results reinforce the idea that pre-Columbian management practices left a lasting ecological legacy, capable of sustaining greater biomass even under the most severe droughts of the century.”

“The results reinforce the idea that pre-Columbian management practices left a lasting ecological legacy, capable of sustaining greater biomass even under the most severe droughts of the century,” Peripato said.

The researchers observed the same pattern in the forest’s wet regions, though it was more subtle. They found that wet areas contained between 80 and 295 megatons of biomass per hectare in 2010 and about 69–290 megatons per hectare in 2020, whereas the parts of the forest showing evidence of human occupation and landscape management held 72–309 megatons per hectare in 2010 and between 64 and 304 megatons per hectare in 2020—approximately 6% above the regional average.

Examples of managed areas included known archaeological sites, such as monumental earthworks, and more than 2,000 confirmed patches of terra preta.

According to Peripato, these sites provide conditions that make the forest’s vegetation healthier and better able to store more biomass and carbon. “The terra preta soils retain more water and nutrients than other soils, allowing the vegetation to grow more vigorously,” he explained. “In the case of earthworks, water can accumulate in the trenches and ditches left in the soil by the old settlements, also favoring the forest growth.”

The higher an ecosystem’s biomass, the greater its carbon stock is, and the more resilient it is. High biomass levels matter especially during droughts, as they help the forest to retain soil moisture, reducing erosion and the risk of forest fires.

“The managed areas of the forest have a much more fertile soil with a greater capacity to retain water,” said Peripato. “Therefore, these areas are much more apt to resist today’s climatic changes.”

A Legacy for the Future

The researchers argue that understanding the ecological impact of this legacy is crucial to developing effective conservation strategies for the forest. Jean Ometto, a senior researcher at INPE who focuses on the ecological impacts of climate change but was not involved with the study, agreed: “It is important to look at biomass distribution in these ancient sites because it can be a reference measurement for mitigation and adaptation projects, such as restoration and reforestation initiatives.” Ometto also serves as the international secretary with AGU’s Board of Directors.

Ometto, who is involved in a project using lidar to locate new archaeological sites in the forest, emphasized the importance of constructive engagement with local Indigenous populations who continue to live in the forest today and are descendants of the region’s early inhabitants.

“Lessons learned over millennia by these communities can be applied to protect the forest today, increase carbon stocks, and make it more resilient.”

These communities, he noted, still possess knowledge about how to interact sustainably with the forest. “Lessons learned over millennia by these communities can be applied to protect the forest today, increase carbon stocks, and make it more resilient,” he said.

Peripato also believes that the Indigenous legacy of landscape modifications may provide natural climate solutions by preserving biomass, biodiversity, and ecological stability despite modern challenges. He added that the scientific community should consider not only ancient modifications but also those currently promoted by Indigenous communities.

“Many Indigenous communities that live in the forest today still do landscape modifications that might be good for the ecosystem,” he said. “We have to try to understand these communities and how they see and manage the forest. I believe that they already have many of the answers.”

—Sofia Moutinho (@sofiamoutinho.bsky.social), Science Writer

Citation: Moutinho, S. (2025), How ancient Indigenous societies made today’s Amazon more resilient, Eos, 106, https://doi.org/10.1029/2025EO250478. Published on 18 December 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.

Volcanoes can erupt in many ways, sometimes blasting plumes of ash and other debris high into the atmosphere or sending rivers of lava downslope.

If an eruption evacuates enough stored magma, the ground overlying a volcano’s reservoir can collapse. The resulting structure, known as a caldera, can be kilometers across and hundreds of meters deep. Caldera-forming eruptions can produce some of Earth’s most hazardous natural phenomena, but they remain in many ways enigmatic despite decades of study.

Enormous caldera-forming eruptions at silicic volcanoes such as Yellowstone are understandably famous. However, collapses at basaltic volcanoes, which erupt less viscous magma and are usually less explosive, can also be highly impactful. Furthermore, basaltic collapses have occurred more frequently in historical times, generally occur more gradually, and can usually be approached more closely than silicic collapses, so they offer important advantages for scientific study.

Since the late 1960s, six caldera collapses are known to have occurred at basaltic volcanoes on land: at Fernandina in the Galápagos Islands (1968), Tolbachik in Russia (1975), Miyakejima in Japan (2000), Piton de la Fournaise on La Réunion (2007), Bárðarbunga in Iceland (2014–2015), and Kīlauea on the island of Hawaiʻi (2018).

Basaltic caldera–forming eruptions present several types of hazards. Clockwise from top left: lava fountains erupt along the rift zone of Tolbachik in Russia in late July 1975; lava flows through populated communities on the island of Hawaiʻi during Kīlauea’s 2018 eruption and caldera collapse; a tephra (ash) plume produced by an incremental collapse event on 19 May 2018 erupts from Kīlauea’s summit; and road damage caused by ground shaking and fault motion in 2018 is seen near the summit of Kīlauea. Credit: Clockwise from top left: Oleg Volynets, Institute of Volcanology, Petropavlovsk, via the Smithsonian Institution Global Volcanism Program, CC BY-NC 4.0; U.S. Geological Survey (USGS) photo by E. Rumpf, Public Domain; USGS webcam photo, Public Domain; USGS photo by K. Anderson, Public Domain

These events have demonstrated that basaltic caldera collapse eruptions can produce complex, cascading sequences of hazards that may occur concurrently over distances of tens of kilometers, with devastating effects on local communities. Hazards include damaging seismicity, ash-rich explosions, gas emissions, and distal eruptions that can discharge lava at hundreds of cubic meters per second for weeks at a time. Residents of the Japanese island of Miyakejima remained evacuated for years after the volcano’s summit collapsed, and the Kīlauea eruption destroyed hundreds of homes in one of the costliest volcanic disasters in U.S. history.

Data collected during caldera collapse eruptions provide unparalleled opportunities to understand some of Earth’s most active volcanoes. The 2018 eruption of Kīlauea was particularly well documented, with extensive observations from real-time monitoring helping to reveal new facets of the volcano’s structure and behavior [Neal et al., 2019]. Such observations have powered leaps in scientific knowledge and inspired renewed focus on understanding caldera-forming eruptions to prepare for and mitigate impacts of inevitable future events [Anderson et al., 2024].

New efforts within the research community are needed to synthesize observations, draw parallels, and identify common physical processes among caldera-forming eruptions. In February 2025, an international and multidisciplinary group of 155 scientists met to address these needs and to provide a springboard for new cross-disciplinary studies. Discussions during that meeting inform the following assessment of what we do and do not understand about this important class of eruption.

Similarities Suggest Common Physics

Comparing observations and interpretations from historical basaltic caldera collapses reveals intriguing commonalities that are remarkable considering the geological contrasts among the volcanoes.

In all six instances, documented collapses were preceded by the lateral intrusion of magma into the crust surrounding summit storage systems. These intrusions propagated as far as tens of kilometers—in many cases feeding fissure eruptions and long-distance lava flows—and in the process drained summit magma and triggered caldera collapses (Figure 1).

Fig. 1. In this conceptual model of basaltic caldera collapse, a dike intrusion and flank eruption withdraw magma from a summit reservoir, which triggers the collapse of the summit caldera that, in turn, sustains the eruption.

In addition, all historical basaltic caldera collapses, with the possible exception of Tolbachik, took place incrementally over days to months through a similar series of abrupt, semiperiodic down drops of the caldera floor (Figure 2). Measurements, where available, show that these incremental collapse events produced magnitude 4–5 earthquakes associated with relatively large amounts of energy at long periods, pushed the ground around the caldera upward and outward, and, in some cases, generated explosive tephra (ash) plumes that rose kilometers into the air.

Fig. 2. During Kīlauea’s 2018 collapse, the ground outside the caldera tilted slowly toward and rapidly away from the caldera as the reservoir depressurized between collapses and was repressurized by collapses, respectively (left axis, black line). The caldera subsided by meters at a time during abrupt collapses (right axis, red line).

These commonalities suggest similar processes. Following the 1968 Fernandina collapse [Simkin and Howard, 1970], a general conceptual model emerged that has since been refined and quantified using observations from subsequent collapses.

In this model, magma withdrawal partially empties a storage reservoir, reducing support for the overlying rock. Eventually, ring faults form in the rock, enabling a pistonlike block to abruptly slip downward into the reservoir under the force of gravity. This subsidence partially repressurizes the reservoir, which stabilizes the piston block and increases the rate of magma outflow, sometimes leading to surges in lava eruption up to tens of kilometers away. Continued magma outflow then reduces reservoir pressure once again, setting the stage for another abrupt collapse event.

Large distal intrusions and eruptions can thus trigger the onset of caldera collapse sequences, which promote further outflow of magma. These sequences explain the large volumes of lava erupted during basaltic caldera–forming eruptions.

Coupled Magmatic-Tectonic Systems

Data collected during caldera collapse eruptions provide unparalleled opportunities to understand some of Earth’s most active volcanoes.

Observations of caldera collapses yield insights that are difficult to glean from more common eruptive activity. One important lesson is that magmatic and tectonic systems can be tightly coupled over an enormous range of spatial and temporal scales and in ways that can result in complex, difficult-to-forecast hazards [Patrick et al., 2020].

For example, at Kīlauea in 2018, magma injection into the volcano’s East Rift Zone triggered a magnitude 6.9 earthquake at the base of the volcano that reduced compressional stress on the rift zone, in turn facilitating increased subsurface flow of magma from the summit into the rift. At Piton de la Fournaise in 2007, the collapse was associated with meter-scale displacement of the volcano’s eastern flank [Froger et al., 2015]. And at Bárðarbunga, the dike that triggered the collapse propagated over a distance of 45 kilometers at a rate and along a direction that were influenced by topography and tectonic stresses [Sigmundsson et al., 2015].

Geophysical and geochemical data collected during collapses can resolve, in unprecedented detail, the locations, volumes, and compositions of magma storage zones, which strongly govern eruptive activity and hazards. Although uncertainties remain, data from the Kīlauea collapse, for example, have placed some of the best constraints on the location and volume of magma storage beneath any volcano.

A scientist samples a lava flow as it crosses a road in Kīlauea’s lower East Rift Zone on 6 May 2018 during the early days of the 2018 eruption and collapse. Credit: USGS photo by K. Anderson, Public Domain

Temporal variations in the composition of erupted lavas demonstrate how fresh magma can mingle with magma stored from decades-old intrusions, influencing eruption rates, dynamics, and hazards. These observations, which can also be used to plumb the hidden pathways between summit magma storage zones and distant eruptive vents, indicate that basaltic rift zones may contain surprisingly large and potentially mobile bodies of magma with a wide range of compositions.

Insights from studying caldera collapses extend beyond volcanology. For instance, despite important differences, slip on caldera ring faults and slip on faults in nonvolcanic settings may be governed by similar physical processes. However, a single caldera collapse sequence may comprise dozens of individual ring fault rupture events, whereas nonvolcanic earthquake cycles often last centuries or longer. Thus, caldera collapse cycles may serve as natural, repeating, field-scale fault-slip experiments, yielding insights into recurrence intervals, fault creep, and the physical properties preceding earthquakes that may ultimately be applicable in places such as the San Andreas Fault [Segall et al., 2024].

The Postcollapse Evolution of Caldera Systems

Many basaltic volcanoes grow through innumerable cycles of caldera collapse and gradual refilling. These decades- or centuries-long cycles (not to be confused with the much shorter incremental collapse cycles during an individual eruption) are integral parts of the long-term evolution of many basaltic volcanoes.

Fernandina caldera, in the Galápagos Islands, collapsed in 1968, dropping by 350 meters, although lava flows and landslide material later filled some of this volume. Benches in the landscape, seen in the foreground and on the opposite side of the caldera in this image taken in January 2001, are evidence of past cycles of caldera collapse and filling. Credit: M. Poland

In contrast to the often fast-paced data gathering conducted during caldera collapses, long postcollapse stretches offer improved opportunities to plan and execute controlled research and to bolster monitoring networks. In the wake of the 2018 eruption at Kīlauea, for instance, congressionally allocated funding has supported important new studies, including the unprecedented deployment of nearly 2,000 seismic stations to resolve the volcano’s subsurface structure, as well as the development of new monitoring and investigative approaches.

Additional insight comes from observations at caldera volcanoes that have not collapsed in historical times despite displaying noteworthy unrest and eruptive activity, such as Ambrym (Vanuatu), Sierra Negra (Galápagos), and Axial Seamount. These observations further elucidate magma storage at caldera systems, dynamic interplays of magmatic and tectonic processes, and conditions required to trigger the onset of collapse.

Caldera collapses are linked with important changes in eruptive activity and hazards.

Caldera collapses are linked with important changes in eruptive activity and hazards. At Kīlauea, major collapses preserved in the geologic record over the past 2,500 years may have led to transitions between centuries-long periods of dominantly explosive and effusive activity [Swanson et al., 2014]. The 2018 collapse was associated with the cessation of a decades-long rift zone eruption and transition to episodic eruptive activity nearer the summit. At Piton de la Fournaise, the 2007 collapse reduced the period of unrest preceding subsequent eruptions, led to an increase in the number of dike intrusions, and increased the proportion of eruptions that occurred near the summit [Peltier et al., 2018].

Although the causes of such transitions are complex and may involve changes in crustal stress and magma supply rate, the effects of collapses on magma storage zones likely play a role. Geochemical analyses of pre- and postcollapse periods indicate that some collapses may strongly affect the structure of shallow magma storage zones (e.g., Kīlauea in 1500, 1790, and 1924), whereas others, such as at Kīlauea in 2018, do not [Lynn and Swanson, 2022]. Similar studies are lacking for many other basaltic caldera volcanoes, such as in the Galápagos, pointing to important avenues for new research.

As magma refills evacuated storage zones, these zones are repressurized, leading to ground deformation, seismicity, and sometimes—as at Bárðarbunga—even reverse slip on caldera ring faults [Glastonbury‐Southern et al., 2022]. Observations of these processes are useful for understanding the geometry and connectivity of magma storage zones, and they shed light on ring fault geometry and mobility.

Open Questions for Future Research

Many fundamental and humbling questions about basaltic caldera collapses remain unanswered, including why some magma intrusions trigger caldera collapse but others do not.

The success of long-standing conceptual models of basaltic caldera collapses suggests that our basic understanding of these remarkable phenomena is solid. Yet many fundamental and humbling questions remain unanswered, including why some intrusions trigger caldera collapse but others do not, what explains variations in collapse sequences among different volcanoes, and why these eruptions end.

We also do not yet know how insights from basaltic caldera collapses are applicable to explosive eruptions and collapses at silicic volcanoes such as Hunga Tonga–Hunga Ha’apai, which in 2022 produced a nearly 60-kilometer-tall ash plume and caused a Pacific-wide tsunami that resulted in several fatalities.

Addressing these questions and improving our ability to forecast basaltic caldera–forming eruptions and mitigate their impacts require improved interdisciplinary collaboration and synthesis of data from historical events. The lessons of the past will find practical application when the next caldera collapse takes place somewhere on Earth.

Acknowledgments

The AGU Chapman Conference on basaltic caldera–forming eruptions was supported by the U.S. Geological Survey (USGS) and the National Science Foundation (NSF EAR grant 2451637). We thank our coconvener, Aline Peltier; AGU conference coordinators Justine Joo and Heather Nalley; all conference participants for their contributions; and observatory scientists and academic investigators around the world for collecting invaluable data during past caldera collapses. Helpful comments were provided by Josh Crozier, Scott Rowland, and an anonymous reviewer. The USGS Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R. 2157), signed by the president in 2019, contributed funding to the USGS to support research, recovery, and rebuilding activities in the wake of Kīlauea’s 2018 eruption. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government.

References

Anderson, K. R., et al. (2024), The 2018 eruption of Kīlauea: Insights, puzzles, and opportunities for volcano science, Annu. Rev. Earth Planet. Sci., 52, 21–59, https://doi.org/10.1146/annurev-earth-031621-075925.

Froger, J.-L., et al. (2015), Time-dependent displacements during and after the April 2007 eruption of Piton de la Fournaise, revealed by interferometric data, J. Volcanol. Geotherm. Res., 296, 55–68, https://doi.org/10.1016/j.jvolgeores.2015.02.014.

Glastonbury‐Southern, E., et al. (2022), Ring fault slip reversal at Bárðarbunga volcano, Iceland: Seismicity during caldera collapse and re‐inflation 2014–2018, Geophys. Res. Lett., 49, e2021GL097613, https://doi.org/10.1029/2021GL097613.

Lynn, K. J., and D. A. Swanson (2022), Olivine and glass chemistry record cycles of plumbing system recovery after summit collapse events at Kīlauea volcano, Hawai‘i, J. Volcanol. Geotherm. Res., 426, 107540, https://doi.org/10.1016/j.jvolgeores.2022.107540.

Neal, C. A., et al. (2019), The 2018 rift eruption and summit collapse of Kīlauea volcano, Science, 363, 367–374, https://doi.org/10.1126/science.aav7046.

Patrick, M. R., et al. (2020), The cascading origin of the 2018 Kīlauea eruption and implications for future forecasting, Nat. Commun., 11, 5646, https://doi.org/10.1038/s41467-020-19190-1.

Peltier, A., et al. (2018), Changes in the long-term geophysical eruptive precursors at Piton de la Fournaise: Implications for the response management, Front. Earth Sci., 6, 104, https://doi.org/10.3389/feart.2018.00104.

Segall, P., et al. (2024), Stress-driven recurrence and precursory moment-rate surge in caldera collapse earthquakes, Nat. Geosci., 17, 264–269, https://doi.org/10.1038/s41561-023-01372-3.

Sigmundsson, F., et al. (2015), Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland, Nature, 517, 191–195, https://doi.org/10.1038/nature14111.

Simkin, T., and K. A. Howard (1970), Caldera collapse in the Galápagos Islands, 1968, Science, 169, 429–437, https://doi.org/10.1126/science.169.3944.429.

Swanson, D. A., et al. (2014), Cycles of explosive and effusive eruptions at Kīlauea volcano, Hawai‘i, Geology, 42, 631–634, https://doi.org/10.1130/G35701.1.

Author Information

Kyle R. Anderson (kranderson@usgs.gov), U.S. Geological Survey, Moffett Field, Calif.; Kendra J. Lynn and Ashton F. Flinders, U.S. Geological Survey, Hilo, Hawaii; Thomas Shea, Department of Earth Sciences, University of Hawaiʻi at Mānoa, Honolulu; and Michael Poland, U.S. Geological Survey, Vancouver, Wash.

Citation: Anderson. K. R., K. J. Lynn, A. F. Flinders, T. Shea, and M. Poland (2025), Lessons and lingering questions from collapsing basaltic calderas, Eos, 106, https://doi.org/10.1029/2025EO250471. Published on 18 December 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.

Erupting from the vast blue expanse of the Pacific Ocean, the Hawaiian Islands are some of the most isolated landmasses on the planet. Communities and ecosystems there depend on a reliable climate that replenishes freshwater resources through regular rainfall. Unexpected disruptions can have serious impacts.

New high-resolution data from the Hawaiʻi Climate Data Portal have helped hydrometeorologist Audrey Nash at the University of Hawaiʻi at Mānoa draw new connections between rainfall and the activity of the Madden-Julian Oscillation (MJO), a global pattern of wind and moisture that regularly passes over the Hawaiian Islands.

The MJO’s direct impact on precipitation is understudied, and Nash hopes investigating its influence on climate variables in Hawaii could improve future predictions of rainfall. Nash will present her research on 19 December at AGU’s Annual Meeting 2025 in New Orleans.

“Hopefully, when [the MJO influence] becomes more understood, it could be implemented into 2- to 3-day forecasting,” Nash said.

A New Look at Old Data

The MJO is a global system that forms in the Indian Ocean and drifts eastward across the tropics in 30- to 60-day cycles before dissipating and re-forming at its origin point. During “active” phases of the MJO, winds at the surface of the ocean push moisture upward, creating rainfall. “Suppressed” phases occur when winds in the upper atmosphere converge and push downward, creating dry conditions as cool moisture hits warmer air and evaporates.

With the help of Koa, a cluster of computers that can perform large computations, Nash combined multiple available datasets that included decades of information on temperature, wind, humidity, seasonal variations, and other climate variables across Hawaii in her study of the MJO’s patterns.

Taking these known variations into account with the movement of the MJO, Nash uncovered patterns that could be used to improve forecasts: Rainfall decreased significantly in Hawaii when the MJO entered a suppressed phase over the Indian Ocean, while an active phase of the MJO occurring in the western Pacific led to substantial increases in rainfall.

John Bravender, a meteorologist with NOAA’s National Weather Service who was not involved in the research, wrote in an email that Nash’s conclusions align with the bigger picture of MJO activity illustrated by NOAA’s Climate Prediction Center (CPC).

“The benefit of the local study compared to the CPC maps,” Bravender wrote, “is that it provides details in much greater resolution and was validated against observed rainfall.”

The El Niño–Southern Oscillation (ENSO) is a more well-known system that modifies climate factors related to rainfall in Hawaii, with La Niña phases leading to wetter rainy seasons compared to El Niño phases. Nash also evaluated MJO-related rainfall signals in the context of ENSO and found that the signals remained valid across ENSO phases. Evaluating these oscillations together helps inform understanding of abnormally high or low precipitation events.

Forecasting Anomalies

“This research shows us that we may be able to use [the activity of the MJO] to improve our forecasts and preparedness messages during the wet season as well.”

“We’re used to looking at the MJO phase to help anticipate tropical cyclone development or rapid intensification,” Bravender wrote. “This research shows us that we may be able to use [the activity of the MJO] to improve our forecasts and preparedness messages during the wet season as well.”

Bravender also noted that this forecasting could be especially important to people relying on rainwater catchment systems who must decide to opt in or hold off on expensive water deliveries during periods of drought.

Past rainfall anomalies in Hawaii have had devastating consequences. Flooding in Kauai in 2018 affected more than 500 homes and cost $20 million in public property damages, and extreme drought contributed to the catastrophic Lahaina wildfire in 2023. More accurate forecasting of these extreme swings in rainfall could help improve water resources management and emergency preparation on these geographically remote islands.

—Kari Goodbar, Science Writer

Citation: Goodbar, K. (2025), Globe-trotting weather pattern influences rainfall in Hawaii, Eos, 106, https://doi.org/10.1029/2025EO250465. Published on 18 December 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
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body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

The Trump administration is planning to dismantle the National Center for Atmospheric Research (NCAR), one of the world’s leading climate and Earth science research laboratories, according to a statement from Russ Vought, director of the White House Office of Management and Budget, to USA Today. 

Vought called the facility “one of the largest sources of climate alarmism in the country” and said the administration had already started a comprehensive review of activities at the laboratory. 

“Vital activities such as weather research will be moved to another entity or location,” Vought said. 

 

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• Get Involved: Speak Out to Save NCAR Today

The National Science Foundation established NCAR in 1960 as the foundation’s first federally funded research and development center. Among other work, NCAR researchers use both models and observations to study weather, air quality, water management, and solar storms. NCAR’s Derecho supercomputer, housed in Wyoming, allows researchers across the country to run detailed models stimulating phenomena such as cyclones and major wildfires.

Among other innovations, scientists at NCAR invented dropsondes, devices that drop from aircraft to measure pressure, temperature, and humidity during storms. They use models that predict how inclement weather will affect road safety. They are developing a turbulence detection system to allow aircraft to avoid rough spots, working to improve hurricane prediction, and projecting atmospheric conditions months in advance to provide guidance for U.S. military planners.

In a statement shared with Eos, Pamitha Weerasinghe, a science policy professional and director of a campaign to strengthen federal science called Knowledge for a Competitive America, said that the work conducted at NCAR has “formed the scientific bedrock on which modern America was built. To propose ‘breaking up’ NSF NCAR is to ignore the needs of American families and industries, and deny them the information and tools they need to prosper.”

The news comes as international Earth and space scientists, many of whom will likely be affected by the news, gather at AGU’s annual conference in New Orleans. Some took to social media to express their disappointment.

“NCAR is quite literally our global mothership,” climate scientist Katherine Hayhoe wrote on Bluesky. “Everyone who works in climate and weather has passed through its doors and benefited from its incredible resources. Dismantling NCAR is like taking a sledgehammer to the keystone holding up our scientific understanding of the planet.”

NCAR is quite literally our global mothership. Everyone who works in climate and weather has passed through its doors and benefited from its incredible resources. Dismantling NCAR is like taking a sledgehammer to the keystone holding up our scientific understanding of the planet.Unbelievable.

— Katharine Hayhoe (@katharinehayhoe.com) 2025-12-17T02:59:29.336Z

Other scientists expressed similar sentiments.

It is hard to overstate how critical @ncar-ucar.bsky.social is to climate science in the US and around the world. It's the beating heart of our field. Generations of scientists have trained there, and almost everyone I know relies on deep collaborations with NCAR scientists. It's end is unthinkable.

— Kim Cobb (@kimcobb.bsky.social) 2025-12-17T02:50:46.254Z

This is absolutely insane and so incredibly shortsighted. NCAR is a global pillar for all atmospheric science and holds the highest of standards for research excellence. We collaborate with NCAR; source data from them; they pioneer scientific breakthroughs.This must not go quietly.

— Brian Matilla (@bxmatilla.bsky.social) 2025-12-17T05:25:14.802Z

As someone not with NCAR, I use NCAR-based software everyday to help identify and track regions of excessive precipitation to help NWS forecasters protect lives and property. NCAR is extremely valuable and we need them.

— Noah Brauer (@noaabrauer.bsky.social) 2025-12-17T04:16:52.073Z

NCAR is home to about 830 employees, but it is not clear how many employees or programs the dismantling will affect. According to a senior White House official who spoke to USA Today, the effort will begin immediately, and includes closing the center’s headquarters: the Mesa Laboratory in Boulder, Colo. The official also flagged several programs the administration considers wasteful, such as efforts to make the sciences more inclusive and research into wind turbines.

In a 16 December statement posted on the NCAR website, Antonio Busalacchi, president of the University Corporation for Atmospheric Research, which manages NCAR, said the center was aware of the Trump administration’s proposal, but had not received additional information.

“NSF NCAR’s research is crucial for building American prosperity by protecting lives and property, supporting the economy, and strengthening national security,” he wrote. “Any plans to dismantle NSF NCAR would set back our nation’s ability to predict, prepare for, and respond to severe weather and other natural disasters.”

In a livestream about the news on Wednesday morning, weather and climate scientist Daniel Swain said NCAR is set to be dismantled for “reasons that do not align with the interests of Americans, which do not align with the interests of really anybody, anywhere in the world.”

“I think this is the moment to be reaching out to your lawmakers and speaking with journalists about the value of NCAR and what would be lost, what will be lost, if the current plan is fully put into motion,” he said.

To voice your support for NCAR, visit this AGU page, where you can find email text and a call script to share with your representatives.

—Emily Gardner (@emfurd@bsky.social), Associate Editor, and 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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It’s now become easier to forecast the next eruption of Alaska’s Bogoslof volcano.

New research led by Pavel Izbekov, a volcanologist at the Alaska Volcano Observatory, is applying the foundations of diffusion chronometry—the study of chemical change in crystals over time—to a new eruption forecasting approach. Izbekov’s team used crystal clusters and their collective records of magma to date and discern the cause of the 2016–2017 Bogoslof volcanic eruption.

They found that around 180 days before the eruption, the volcano experienced a rapid ascent of magma to a shallow storage chamber under the surface of the volcano, where it accumulated until it erupted. These findings can be used in tandem with other monitoring methods to more accurately anticipate the next eruption at Bogoslof and other volcanoes.

“Understanding how [volcanoes] work, understanding what precedes an eruption, and the ability to forecast volcanic behavior is extremely important for our safety,” Izbekov said. The team presented their findings on 17 December at AGU’s Annual Meeting 2025 in New Orleans.

Crystal Clusters as Clocks

A volcanologist reconstructing the history of magma with zone records is “like a forensic detective trying to figure out a crime scene in a crystal,” said Hannah Shamloo, a volcanologist at Central Washington University who was not involved in the new research.

A volcanic crystal grows from its core outward, developing concentric zones each time it experiences a major event. Visible under an electron microprobe, the zones resemble a tree’s growth rings, which capture the chemical reactions spurred by a particular event. The innermost zones near the crystal’s core reflect early life events, while the outermost zones along the rim depict activity later in life.

“If you look at the pair [of crystals], which responded to the same event simultaneously, well, we’re in business.”

The challenge is that multiple events can yield the same chemical reaction within a zone. To eliminate competing possible causes of the Bogoslof eruption, Izbekov and his colleagues looked not just at one crystal, but at a cluster of crystals of different types. If volcanologists look not just at the plagioclase, whose zone records they can attribute to a few possible explanations, but also at a clinopyroxene, whose zone records point to a different set of explanations, they can find a common denominator by the process of elimination.

“If you look at the pair, which responded to the same event simultaneously, well, we’re in business. This is the beauty of this new approach,” Izbekov said.

From Past to Future

Bogoslof was an optimal case study for cluster chronometry because the magma in its chamber below the seafloor is rich in crystals that record clear responses to pressure and temperature changes.

The team analyzed plagioclase-clinopyroxene-amphibole clusters within samples of basalt that erupted from Bogoslof in August 2017, toward the end of a 9-month eruption period. The conjoined crystals shared zone boundaries, indicating that they experienced the same events in the magma chamber.

One event stood out because the three minerals responded very differently: The clinopyroxene crystals suddenly decreased in magnesium content, the plagioclases decreased in anorthite content, and the amphiboles stopped growing. Izbekov and his team determined that decompression, a rapid drop in magmatic pressure that happens when magma ascends toward the volcanic surface, is the best explanation for all three distinct responses across the crystals’ zones.

Now, when a seismometer picks up signs of decompression at Bogoslof, a roughly 180-day countdown until eruption can begin.

The researchers then attempted to date the decompression event and found that it happened no more than 180 days prior to the end of the second eruption in August, around early March 2017. They validated their detective work in the cluster investigation by comparing their results with those from established geochemical monitoring methods. Monitors had picked up higher seismic activity and sulfur dioxide emissions—two indicators of magma’s ascent through the crust and the corresponding drop in pressure—at Bogoslof in March 2017, which supported the team’s findings.

In the future, when a seismometer picks up signs of decompression at Bogoslof, a roughly 180-day countdown until eruption can begin—if an eruption happens when expected, it would further validate the diffusion chronometry technique.

Predictive Power of Crystals

Shamloo was encouraged by the results but cautioned that there was still much to decipher about how crystals record a volcano’s inner workings.

“There’s a lot that can happen to the crystal record that can confuse a geologist,” Shamloo said.

The temperature of the magma at the point of diffusion is one of those confusing, yet essential, components. While the exact temperature of the basalt is unknown, Izbekov and his colleagues “did a careful job handling their assumptions for their model to minimize uncertainty,” Shamloo said.

“I do think relying on the crystal record in general is becoming a useful ‘monitoring’ tool for volcanoes,” Shamloo said. “There is power in reading the crystal record to really understand eruptive histories and potentially how a volcano will erupt in the future.”

—Claudia Steiner (@claudiasteiner.bsky.social), Science Writer

Citation: Steiner, C. (2025), Crystal clusters contain clues to magma’s past and future eruptions, Eos, 106, https://doi.org/10.1029/2025EO250475. Published on 17 December 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.

Years before the first telescope was invented, sky-gazers made their rooms into pinhole cameras and took pen to paper, drawing the Sun and the little dark spots that moved across its face day by day. Sunspot drawings date back more than 2,000 years to astronomers in ancient China and, many centuries later, to Western scientists like Galileo and Kepler.

Now science historians worldwide have come together to compile and digitize 400 years’ worth of sunspot drawings in the hopes of illuminating solar activity of the past and informing our present understanding. Solar physicist Andrés Muñoz-Jaramillo used this digitized collection of sunspot observations to develop a collection of software tools to analyze solar cycles and reconstruct missing gaps.

“When we think about how much our capability of observing the [solar] cycle has evolved during the past decades—it’s incredible,” said Muñoz-Jaramillo, a senior research scientist at the Southwest Research Institute in Boulder, Colo. “The quality, resolution, cadence, everything.”

Learning from the Past

Solar cycles typically last 11 years, but Muñoz-Jaramillo said that the best instruments for observing the Sun, like the Parker Solar Probe and the Solar Dynamics Observatory, have been around for only about 2 decades. To understand solar variability going back centuries, researchers must look to techniques of the past.

“Whenever we’re dealing with long-term variability, we don’t have the luxury of waiting 100 years to get better data,” said Muñoz-Jaramillo.

Before the invention of the photograph, astronomers would point a solar telescope at the Sun and use the eyepiece to project the image upon a surface covered with paper. They would sketch the sunspots they observed that day and denote the time and date. Over time, the spots appeared to move across the page and grow or shrink or change shape. Some of these records of solar activity have survived to the present day, often gathering dust in neglected corners of archives.

Historians have been diligently collecting and digitizing centuries of drawings and creating detailed logs of the position and size of spots over time. Researchers are now using these logs to study the long-term variability of the Sun.

“A huge part of this work is done by our historian friends. They are like detectives.”

“A huge part of this work is done by our historian friends. They are like detectives,” said Muñoz-Jaramillo. “The real heroes are those that went from archives to basements and traveled all over the world and talked with people, convinced them to let them in, allowed them to take pictures.”

But hundreds of years’ worth of data are difficult to handle. So Muñoz-Jaramillo and his colleagues developed a computational framework to support the efforts of solar cycle researchers worldwide. This collection of software tools uses Bayesian statistics to fill in the gaps where sunspot data may not be available.

“You can make these statements now in a probabilistic way about what went on in these historical periods,” said Muñoz-Jaramillo.

The researchers used this new framework to learn more about the Maunder Minimum, a time period in the 15th century when the Sun was less active and very few sunspots were observed—a few dozen in comparison to the tens of thousands typically observed. With so few data points, any additional information can help scientists better understand the solar activity of the time, Muñoz-Jaramillo said. They also examined another slow activity period in the late 16th century called the Dalton Minimum and compared recent solar activity to that of previous centuries.

Using this framework, they learned that the Maunder and Dalton Minima might have been preceded by other cycles with deep minima in solar activity spread far apart in time. Some heliophysicists speculate that there may be entire solar cycles’ worth of observations missing, Muñoz-Jaramillo said.

Muñoz-Jaramillo and his colleagues presented these results on 16 December at AGU’s Annual Meeting 2025 in New Orleans.

Spotting the Sun’s Evolution

Solar cycle researchers typically observe cycles with what are known as butterfly diagrams, plots of the time and latitude of sunspots. These plots can be used to understand the long-term variability of the Sun by comparing modern and historic data and noting parallels between them. Researchers can reconstruct past solar cycles using this new computational framework and can analyze them using butterfly diagrams to better understand how the Sun has changed in recent centuries.

“It’s a service to the community. We put all these things together to make it easier for any modern scientist to work with.”

“This study is highly innovative because, until now, reconstructions of past solar activity have relied solely on sunspot counts,” José Manuel Vaquero Martínez, a physics professor at the Universidad de Extremadura who was not involved in the study, said in an email. “In contrast, this approach incorporates not only the number of sunspots but also their positions. In other words, it leverages our understanding of how solar active regions (in this case, sunspots) evolve to reconstruct past solar activity.”

The team hopes their work will enable researchers to tap into the treasure trove of historical data more easily than before, Muñoz-Jaramillo said. “It’s a service to the community. We put all these things together to make it easier for any modern scientist to work with.”

—Daniella García Almeida, Science Writer

Citation: García Almeida, D. (2025), Sunspot drawings illuminate 400 years of solar activity, Eos, 106, https://doi.org/10.1029/2025EO250477. Published on 17 December 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Source: AGU Advances

Earth system models offer insight into how climate change will affect communities. But residents of those communities are rarely consulted on the design and deployment of these models, which can lead to the models being misused in local decisionmaking. To bridge this divide, Cheng et al. collaborated with Indigenous communities in two regions to model the effects climate change will have on their land.

In the Arctic Rivers project, the researchers worked with Indigenous communities across Alaska to model how climate change will alter rivers and streams. In the Mid-Klamath project, the researchers worked with the Karuk Tribe in Northern California to study how different wildfire management strategies would affect local hydrology.

In both cases, mismatches existed between the methodology available to the researchers and the needs of the end users, and the collaborators mitigated these mismatches to varying extents. In the Arctic Rivers project, for example, constraints on computational resources limited the number of future scenarios the researchers could model. Thanks to involvement from the project’s own Indigenous Advisory Council and the Yukon River Inter-Tribal Watershed Council, the researchers were able to prioritize the scenarios most relevant to the communities.

In the Mid-Klamath project, on the other hand, misunderstandings at the start of the project led the researchers to choose a modeling tool that didn’t fully meet the expectations of the tribe. More extensive discussions during early stages of the project could have avoided this issue, the researchers noted, and the National Science Foundation has recently begun to change its granting system to allow for these early discussions.

Accurately communicating the limits of the available technology is crucial, the researchers wrote. For example, one member of an Alaskan community stated that conditions in the region were changing so quickly that they needed subseasonal projections in addition to decade-scale projections. Unfortunately, the former were beyond the technical expertise of the scientists involved in the project. But scientists were careful not to mislead the community into thinking such a thing was possible in that project.

Cultural humility and spending ample time with Indigenous communities are both cornerstones of successful collaborations, the researchers wrote. At the same time, it’s important to acknowledge the capacity constraints that many scientists face. In addition, it is valuable to offer roles involving reasonable time commitments to scientists with fewer resources, so as not to exclude them from the codesign process. (AGU Advances, https://doi.org/10.1029/2025AV001921, 2025)

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

Citation: Sidik, S. M. (2025), Climate modeling for communities, with communities, Eos, 106, https://doi.org/10.1029/2025EO250473. Published on 17 December 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.

NOAA released this year’s Arctic Report Card on 16 December at AGU’s Annual Meeting 2025 in New Orleans. The report gives an update on changes to the region’s climate, environment, and communities and documents these changes for future scientists looking to the Arctic’s past.

In 2025, parts of the Arctic experienced record-breaking temperatures, low sea ice extent, and other extreme climate events. Credit: NOAA’s Arctic Report Card 2025

After 2 decades of the U.S. government producing the annual report, however, datasets and resources used to create it may be under threat as federal science agencies lose staff and plan for funding uncertainties.

“There is growing concern over how the U.S. will be investing in Arctic research,” said Matthew Druckenmiller, an Arctic scientist at the National Snow and Ice Data Center and lead editor of the report.

Another Year of Arctic Records

From October 2024 to September 2025, the time period analyzed by the report, Arctic surface air temperatures were the warmest on record. The past year in the Arctic marked the region’s warmest autumn, second-warmest winter, and third-warmest summer ever.

This year, the Arctic also had the most precipitation ever recorded, with its wettest spring on record and higher than normal winter snow cover. “To see both those records [precipitation and surface air temperature] set in a single year was remarkable,” Druckenmiller said.

Seasonal surface air temperature anomalies (in °C) for (a) autumn 2024, (b) winter 2025, (c) spring 2025, and (d) summer 2025. Temperature anomalies are shown relative to their 1991–2020 means. Hatching indicates the warmest seasonal temperatures since 1940. Source: ERA5 reanalysis air temperature data were obtained from the Copernicus Climate Change Service. Click image for larger version. Credit: NOAA’s Arctic Report Card 2025

Sea ice in the Arctic continues to hit new lows: Maximum sea ice extent this winter was the lowest observed in the 47-year satellite record. As sea ice shrinks, the Arctic becomes less reflective, exacerbating climate change as the region absorbs, rather than reflects, more heat from the Sun. Ice on land also continues to melt—the Greenland Ice Sheet lost mass in 2025, as it has every year since the late 1990s.

As the region warms, the Arctic Ocean and associated waterways are changing, too. “Atlantification,” a northward intrusion of warm, salty water from the Atlantic, is altering the Arctic Ocean, leading to decreased winter sea ice and creating conditions for more frequent algal blooms. How this influx of water will affect ecological communities in the Arctic remains one of the biggest unanswered scientific questions about the Arctic, said Igor Polyakov, an oceanographer at the University of Alaska Fairbanks and coauthor of the report.

Data Difficulties

Data included in the report are collected by the Arctic Observing Network (AON), an internationally coordinated system of data observation and sharing.

But obstacles impede the system’s ability to monitor the Arctic, according to report authors. Sparse ground-based observation systems, unreliable infrastructure, limited telecommunications, and satellites operating beyond their mission lifetimes are hindering data collection and sharing. “Persistent gaps limit the AON’s ability to fully support Arctic assessments and decision-making,” the authors write.

Science agencies such as NOAA, NASA, and the National Science Foundation and the Interior Department contribute significantly to AON, but all faced staff and budget reductions in 2025. These changes could affect AON and its ability to publish the Arctic Report Card, “jeopardizing long-term trend analyses and undermining decision-making,” the authors write.

Though the Arctic Report Card team received “great support” from NOAA and the report was successfully published, “there were some difficult moments this year,” Druckenmiller said.

“Data doesn’t interpret itself.”

In particular, the shutdown of climate.gov, the NOAA website that housed most of its climate science information, slowed the team’s ability to create the report’s graphics. The federal shutdown in October and November delayed the processing of key datasets, notably one from NASA that documented surface air temperature.

In addition, the report points out that federal budget proposals for 2026 may affect multiple datasets and observation systems used in the report. The three primary sea ice–observing systems (CryoSat-2, Soil Moisture and Ocean Salinity (SMOS), and Ice, Cloud, and land Elevation Satellite 2 (ICESat-2)) are all operating past their mission lifetime, as well. And in July, the Department of Defense decommissioned its Defense Meteorological Satellite Program, which tracked meteorological, oceanographic, and solar-terrestrial physics in the Arctic and elsewhere.

“When these long-standing data products are decommissioned, you really lose a lot of data continuity, which is really important if you’re going to accurately document long-term trends,” Druckenmiller said.

Losing expert scientists at federal science agencies, labs, universities, and research institutions will likely pose challenges, too, he added. “Data doesn’t interpret itself.”

Indigenous-Led Data Collection

Rapid changes to the Arctic are stressing the human communities there: Permafrost thaw releases potential toxicants into drinking water, wetter weather contributes to flooding, and changes to snowfall and ice affect travel. The remnants of Typhoon Halong brought extreme winds and surging water to Alaska’s southwestern coast in October 2025, flooding communities and forcing more than 1,500 residents to evacuate.

Data give these communities—many of which are majority Indigenous—a better ability to respond to climate change, and a weaker AON could impede flood prediction and community adaptation plans, the report states.

As the availability of federal data and resources remains uncertain, Indigenous-led monitoring networks highlighted in the report have provided another model.

Sentinels from the Indigenous Sentinels Network and two NOAA officials conduct surveys on northern fur seal rookeries on St. Paul Island, Alaska. Credit: Hannah-Marie Ladd, NOAA’s Arctic Report Card 2025

The Indigenous Sentinels Network, for example, is a tribally owned and operated cyber infrastructure system supporting Indigenous-led environmental monitoring. Sentinels collect observational data on a range of environmental systems, from wildlife to coastal erosion to tundra greening. The data collected are governed by the communities that collect them and used locally for decisionmaking, collaborative research projects, and climate adaptation planning.

The Building Research Aligned with Indigenous Determination, Equity, and Decision-making (BRAIDED) Food Security Project, another example of an Indigenous-led monitoring project, tracks mercury in locally harvested foods to ensure food safety. All the samples are processed and tested locally on St. Paul Island in Alaska.

“These are models that can be used for resilience everywhere.”

This type of place-based, community-led monitoring is “foundational to understanding and responding to rapid change” facing the Arctic, said Hannah-Marie Ladd, program director for the Indigenous Sentinels Network and author of the new report.

“Indigenous-led monitoring can, and always has, complemented federal science by providing year-round, place-based observations that are often missing” from short-term field seasons, she said. “[Sentinels] live in these environments, and they can detect changes earlier and interpret them with cultural and ecological context that is often missing when outside entities come into a new relationship with a place.”

Such a framework will become only more valuable as the Arctic, and the rest of the world, warms. “These are models that can be used for resilience everywhere,” Ladd said.

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

Citation: van Deelen, G. (2025), Amid the Arctic’s hottest year, Arctic science faces a data deficiency, Eos, 106, https://doi.org/10.1029/2025EO250482. Published on 16 December 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.

Extreme wildfire events are becoming more frequent globally, a pattern that carries a risk for human health. Inhaling smoke from fires can send small bits of particulate matter into airways, aggravating asthma and decreasing lung function. But another, far less understood danger is hitching a smokey ride alongside these aerosols: fungi.

Researchers are increasingly recognizing how wildfire smoke can scatter microorganisms like fungi into the air. This phenomenon is part of a budding field called pyroaerobiology, explained Leda Kobziar, a wildland fire scientist at the University of Idaho in Moscow who has been studying the relationship between airborne spores and wildfire smoke since 2018.

New research from Kobziar’s team has confirmed that smoke-borne fungal spores can cause lung disease in mice. Her team took smoke samples from wildfires, isolated the fungal species within them, and exposed mice to these samples. Many of the mice soon showed symptoms of lung disease. The team will present its findings on 16 December at AGU’s Annual Meeting 2025 in New Orleans.

Catching Fire

“It was really an unknown that there were living microorganisms in wildland fire smoke. I think most people assumed that it was sterile because it comes from a hot fire.”

Studying the living side of smoke is a relatively new practice. “It was really an unknown that there were living microorganisms in wildland fire smoke. I think most people assumed that it was sterile because it comes from a hot fire,” said Phinehas Lampman, a former wildland firefighter, coauthor on the study, and wildland fire scientist at the University of Idaho.

The first study exploring the problem was published in 2004 by then–high school student Sarah Mims and her father, who used a smoke detector attached to a kite to collect fungal samples and correlate them with smokey days.

While there are more pyroaerobiologists today than there were 20 years ago, there are still many unanswered questions about what, how, and to what effect fungal spores travel with smoke.

For the new study, Kobziar, Lampman, and their team developed drone-based sampling systems to collect fungal samples and record conditions like temperature and humidity in wildfire smoke. Over a period of 4 years, the team conducted more than 100 drone flights into grassland and conifer forest fires across nine different areas, including sites in Utah, California, Kansas, and Florida.

A majority of the sampling was done at prescribed burns intentionally set by firefighters to reduce wildfire hazard. The controlled nature of prescribed burns allowed the researchers to get up close to fires and better maneuver their drones for sampling.

The team found that wildfire smoke from the prescribed burns contained spore concentrations of up to 400,000 spores per cubic meter, 4 times higher than the threshold that has been shown to decrease lung function.

To find out whether the fungal species present in smoke pose a health risk, the team used spores from the smoke samples to grow and isolate fungal colonies. They found 110 unique fungal taxa, 9 of which were identified to be potential human pathogens.

The researchers then exposed mice to these isolated samples. Over the course of a few weeks, the animals developed symptoms of lung disease in response to three different fungal taxa, suggesting that some fungi in wildfire smoke have the potential to negatively affect human health as well.

Exploring Health Impacts of Fungi in Smoke

Prescribed burns typically burn the same biomass as wildfires, so the composition of fungi in the smoke is likely similar. “But wildfires have a very different size footprint and typically generate a lot more power,” Kobziar said, explaining that large natural fires have the potential to generate much more advection of air and carry more diverse microbes.

Clouds of wildfire smoke with large distributions can act as vectors and scatter potentially dangerous fungi into new areas, said coauthor Borna Mehrad, a pulmonologist at the University of Florida in Gainesville.

“As fires become more frequent, this will become a progressively bigger issue. It’s something that we as physicians hadn’t even considered.”

“As fires become more frequent, this will become a progressively bigger issue,” he said. “It’s something that we as physicians hadn’t even considered.”

Despite the concerning finding, it’s important to note that not all fungi dispersed by wildfire smoke are a concern for human health, said Jennifer Head, an epidemiologist at the University of Michigan in Ann Arbor who was not involved in the new research. “The species of fungus matters a lot in terms of what is the risk posed to human health.” She stressed the need for future research to characterize which fires, and where, are most concerning as vectors for dangerous fungi.

Looking forward, the team seeks to differentiate the various causes of lung disease and uncover what proportion of negative health effects are caused by smoke-borne fungi. The team hopes their findings could help protect people on the frontlines of major burns, like wildland firefighters.

“This is really just the opening of the box of discovery,” Kobziar said.

—Alonso Daboub (@AlonsoDaboub), Science Writer

Citation: Daboub, A. (2025), Fungal spores in wildfire smoke could cause lung disease, Eos, 106, https://doi.org/10.1029/2025EO250470. Published on 16 December 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.

During the ninth century BCE, King Mesha reigned over Moab, a kingdom located in what is now Jordan. Details of how King Omri of Israel ruled the Moabites, Mesha’s subsequent rebellion, and numerous construction projects Mesha undertook as monarch were recorded on a slab of stone around 840 BCE.

The Moabite Stone, found in 1868 in modern-day Dhiban, Jordan, and now on display at the Louvre Museum in Paris, tells a story seemingly contemporaneous with one from the biblical Book of Kings, but from a different perspective. Artifacts that illuminate biblical times hold great importance for archaeologists, museums, and collectors—so much that forgeries fetch great sums.

Artifacts from the biblical era are so valuable that in one infamous example, an entire class of reproductions, the Moabite forgeries, was created soon after the discovery of the Moabite Stone. The Moabite forgeries consist of clay vessels, figurines, and other items crafted in the 19th century. Some are inscribed with Phoenician script selected from the real Moabite Stone. The inscriptions on the Moabitica, as the forgeries are called, translate to nonsense, and the clay used to fashion the frauds came not from Jordan but from clays around Jerusalem.

This photograph of Moabitica pottery, a known forgery, features symbols written in Phoenician that translate to nonsense. This particular piece has been sampled for future paleomagnetic analysis. Credit: Published with the permission of the Institute of Archaeology of the Hebrew University of Jerusalem; photo by Mimi Lavi, Conservation Lab. Eos thanks Daphna Tsoran, Curator of the Collection Room at the Institute of Archaeology of the Hebrew University of Jerusalem, for permission to access this object.

The Moabite forgeries and other fakes can be used to validate ways to authenticate archaeological finds. In a pair of studies that will be presented at AGU’s Annual Meeting 2025, Scripps Institution of Oceanography postdoctoral scholar Yoav Vaknin will explore ways to verify archaeological finds using something that’s hard to imitate—Earth’s paleomagnetic field.

A Record in Clay

Earth’s magnetic field, which has both a direction and a strength, changes over time. North and south swap poles every so often. The intensity of the field—how strong it is at a particular location or at a particular time—also rises and falls.

“You can use these changes as a dating tool for archaeology,” explained Vaknin. “But first, you need to know how it changed over time.” To that end, Vaknin and colleagues had previously conducted a study compiling paleointensity measurements of the magnetic field for well-dated antiquities at the time they were produced, painstakingly reconstructing how the intensity changed in and around the Levantine region.

“We can use this reconstruction of the field to date [an] object.” This technique is also how forgeries can be detected.

“Artifacts are known to be really good magnetic records in part because they’re fired to really high temperatures,” said Courtney Sprain, a paleomagnetist at the University of Florida who was not involved in this study. In the kilns and ovens that harden clay, temperatures can reach 1,200°C (2,192°F). At these temperatures, chemical reactions cause new minerals to form, including iron-rich magnetite that locks in the status of Earth’s magnetic field—both direction and intensity—at around 580°C (1,076°F). Because pots don’t remain in place after they’ve been fired, the direction isn’t especially useful. But the magnetic field’s intensity is.

A marked increase in magnetic field intensity, more than twice that of today’s field, took place in the Levant from about 1050 to 700 BCE. Called the Levantine Iron Age anomaly, it has been documented across the region, recorded in artifacts and rocks from Cyprus, Israel, Jordan, Syria, and other locales.

Because the paleointensity timeline has been established for the region, “if we have materials that aren’t well dated, we can use this reconstruction of the field to date [an] object,” Vaknin said. This technique is also how forgeries can be detected.

Real or Fake

The Iron Age overlaps with much of the biblical period, Vaknin said. This is the time when many of the Bible’s stories—like those of King Mesha and King Omri—took place.

This time is an important part of human history, so people want these artifacts. As a result of this demand, Vaknin said, “they’re worth a lot of money.”

If an artifact comes to or from an antiquities market, private collection, or museum without information about the archaeological dig where it was excavated, “we don’t know how it got there,” said Vaknin. “There isn’t a method that’s really 100% secure to say if something is authentic.”

Researchers often disagree in their assessments of authenticity, with debates spilling into the academic literature about whether important items are legitimate or mere imitations.

If the artifact looks like it came from this time but has a magnetic field of today, “then it’s clearly fake.”

Measuring the paleomagnetic intensity of a disputed artifact can help archaeologists determine whether the artifact was made recently or during a time with a distinctly different paleomagnetic field than today’s. For instance, in Vaknin’s work, he demonstrates that forgeries were clearly fired at a time with today’s magnetic field intensity—not at the time of the Levantine Iron Age anomaly. If the artifact looks like it came from an earlier time but has a magnetic field of today, “then it’s clearly fake,” Vaknin said.

With this proof of concept, Vaknin and his colleagues have begun to look at artifacts of unknown authenticity that are under vigorous debate.

One limitation of the method is that it works only for authenticating artifacts from times when the paleomagnetic field was very different from the modern field, Vaknin cautioned. He and his colleagues are addressing that limitation by combining novel modeling and experiments related to how the magnetization of an item of interest can detectably change at low temperatures—the topic of another AGU25 presentation.

“This is one of the really cool examples of where [paleomagnetic] data can help with the study of archeology in general,” said Sprain regarding Vaknin’s work on using paleointensity. “Any artifacts that were from this area [and] from that time period, they have to have this strong magnetic signal.”

—Alka Tripathy-Lang (@dralkatrip.bsky.social ), Science Writer

Citation: Tripathy-Lang, A. (2025), Credible or counterfeit: How paleomagnetism can help archaeologists find frauds, Eos, 106, https://doi.org/10.1029/2025EO250449. Published on 16 December 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

Yesterday, I posted about the landslide disaster that struck Malalak in Sumatra at the end of November 2025. Unfortunately, that is just a tiny component of the catastrophe that has occurred in this part of Indonesia.

The BGS has used imagery released under the Disaster Charter to map landslides triggered by this event in Sumatra – their map shows a lower estimate of 4,326 landslides, but this is a massive underestimate:-

British Geological Survey map of landslides triggered by the November 2025 rains in Sumatra.

This is a dramatic image, and the BGS have done a great job to compile this map, but it covers just a small part of the affected area (Malalak is not in this part of Sumatra), and the mapping does not capture all of the landslides. For example, the southern banks of Takengon Lake, in the centre of the image, has no mapped landslides. However, this is how that area looked on the 30 November 2025 Planet Labs PlanetScope satellite image (the centre marker is at [4.57347, 96.87513]:-

Landslides on the southern side of Lake Takengon in Sumatra triggered by the November 2025 rains. Image copyright Planet Labs, used with permission, collected on 30 November 2025.

This is a classic situation that I have described repeatedly in recent years – intense rainfall triggering hundreds of thousands of shallow landslides, which then form channelised debris flows. Take a look at the area on the immediate banks of the lake. This is this area as of 28 October 2025 and on 29 November 2025:-

Planet Labs images from 28 October 2025 and on 29 November 2025 (https://www.planet.com/).

Note the devastation that the channelised flows have inflicted on the communities. This pattern is replicated over a massive area of Sumatra. I wonder if this is the largest landslide event on record in terms of the number of individual failures, surpassing even Cyclone Gabrielle in New Zealand.

Loyal reader Alasdair MacKenzie kindly highlighted that there is some footage of the debris flows at Malalak on social media:-

Acknowledgement

Thanks as always to Planet Labs (2025) for their amazing imagery.

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.