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Across the western U.S., wildfires and the dangerous smoke that results have increased in frequency and intensity since the 1990s—that much is clear. Surprisingly less clear are the exact reasons why: While greenhouse gas-related global warming is often cited as a culprit, to what extent can this claim be quantified?

In the midst of the COVID pandemic, scientists embarked on an ambitious research expedition to the North Atlantic to investigate the inner workings of the ocean's carbon cycle. A series of storms hammered the three vessels, among the most advanced research ships in the world, while bureaucratic mayhem threatened to scrub the voyage entirely.

When Santa is done delivering presents on Christmas Eve, he must get back home to the North Pole, even if it's snowing so hard that the reindeer can't see the way.

A new study provides evidence that the ocean may have absorbed as much as 15% (0.3–0.4 Pg C yr-1) more CO2 than previously thought, requiring a re-think of future CO2 flux assessments and global climate models.

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.

Intense storms that sweep over the Southern Ocean enable the ocean to absorb more heat from the atmosphere. New research from the University of Gothenburg shows that today's climate models underestimate how storms mix the ocean and thereby give less reliable future projections of our climate.

When it comes to global warming and greenhouse gases, methane is one of the bad guys. It's the second most important contributor to climate change after carbon dioxide. However, quantifying the exact amount being released has been a matter of guesswork. But now the first-ever global map of methane leaks from industrial sites is giving us detailed information on where this greenhouse gas is escaping, how much is escaping, and how often it occurs.

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.

A climate study led by The Hong Kong University of Science and Technology (HKUST), in collaboration with an international research team, reveals that under a high-emission scenario, the Northern Hemisphere summer monsoons region will undergo extreme weather events starting in 2064. Asia and broader tropical regions will face frequent "subseasonal whiplash" events, characterized by extreme downpours and dry spells alternating every 30 to 90 days which trigger climate disruptions with catastrophic impacts on food production, water management, and clean energy systems.

SummaryThe strength of the subduction interface plays a major role in controlling subduction dynamics on both local and global scales. While previous studies have primarily examined interface strength in two-dimensional models, natural subduction zones are inherently three-dimensional, with interface strength varying along-strike due to spatial differences in factors such as sediment input. Here, we use the geodynamic code ASPECT to conduct fully dynamic 3D subduction models in which interface strength varies along-strike. We find that the interaction between strong and weak segments of the interface leads to a narrower range of convergence velocities while broadening the range of viable interface stresses compared to 2D or homogeneous 3D models. Stronger segments, when adjacent to weaker ones, exhibit increased convergence velocities. This promotes higher interface stresses and facilitates the subduction of otherwise stagnant strong segments. We find that the interface viscosity of the strong segment controls the baseline stress, whereas the viscosity contrast along-strike controls the magnitude of amplification of the stress due to velocity increases. The elevated interface stresses at strong segments also generate greater compressional forces in the overriding plate than expected from 2D models. Combined with along-strike variations in convergence velocity, this results in trench migration, with stronger segments displaying more advanced trench positions relative to weaker segments. Possible natural analogs include the Bolivian Orocline in the central Andes and the Lesser Antilles, both of which show enhanced overriding plate compression and trench advance in areas of reduced sediment supply.

SummaryRealistic models of earthquake sequences can be simulated by assuming faults governed by rate-and-state friction embedded in an elastic medium. Exploring the possibility of using such models for earthquake forecasting is challenging due to the difficulty of integrating Partial Differential Equation (PDE) models with sparse, low-resolution observational data. This paper presents a machine-learning-based reduced-order model (ROM) for earthquake sequences that addresses this limitation. The proposed ROM captures the slow/fast chaotic dynamics of earthquake sequences using a low-dimensional representation, enabling computational efficiency and robustness to high-frequency noise in observational data. The ROM’s efficiency facilitates effective data assimilation using the Ensemble Kalman Filter (EnKF), even with low-resolution, noisy observations. Results demonstrate the ROM’s ability to replicate key scaling properties of the sequence -namely the magnitude-frequency, moment-duration, and moment-area relationships- and to estimate the distributions of fault slip rate and state variable, enabling predictions of large events in time and space with uncertainty quantification. These findings underscore the ROM’s potential for forecasting and for addressing challenges in inverse problems for nonlinear geophysical systems.

The summer of 2025 brought unprecedented flash flooding across the U.S., with the central and eastern regions hit particularly hard. These storms claimed hundreds of lives across Texas, Kentucky and several other states and caused widespread destruction.

While scientists have long known that iron oxide minerals help lock away enormous amounts of carbon—sequestering it from the atmosphere—a new Northwestern University study now reveals exactly why these minerals are such powerful carbon traps.

Publication date: Available online 9 December 2025

Source: Advances in Space Research

Author(s): A.I. Sapunova, I.A. Ryakhovsky, Y.V. Poklad, B.G. Gavrilov, V.S. Lobanova, V.M. Ermak, E.N. Kozakova

Publication date: Available online 9 December 2025

Source: Advances in Space Research

Author(s): Achille Zirizzotti, Umberto Sciacca, Enrico Zuccheretti, Carlo Scotto, Loredana Perrone, James Arokiasamy Baskaradas

Publication date: Available online 9 December 2025

Source: Advances in Space Research

Author(s): Cafer BUDAK

Publication date: Available online 9 December 2025

Source: Advances in Space Research

Author(s): Yangyang Liu, Ju Hong, Rui Tu, Shengli Wang

Publication date: Available online 9 December 2025

Source: Advances in Space Research

Author(s): Woo-Min Cho, Hyun-Ung Oh