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The Trump administration has finalized a plan to roll back regulations outlined by one of the nation’s bedrock environmental laws.

Signed into law in 1970, the National Environmental Policy Act (NEPA) requires federal agencies to assess how proposed major projects—such as the purchase of parklands, the establishment of military complexes, or the construction of buildings and highways—will impact the environment.

NEPA opponents, which include both Republicans and Democrats, claim the processes outlined in the legislation unnecessarily delay approvals for infrastructure and energy projects. Last February, the Council on Environmental Quality (CEQ) published an interim final rule removing NEPA regulations. The new action adopts the rule as final.

 
Related

• From the White House: CEQ Fixes Decades-Long Permitting Failure Through Deregulation
•  Removal of National Environmental Policy Act Implementing Regulations
•  Letter from Environmental Organizations During Public Comment Period
• Trump administration finalizes plan to roll back federal environmental guidelines under bedrock law
•  White House claims to end NEPA’s ‘regulatory reign of terror’
 

“In this Administration, NEPA’s regulatory reign of terror has ended,” said CEQ Chairman Katherine Scarlett in a statement. “Thanks to President Trump’s leadership, CEQ acted early to slash needless layering of bureaucratic burden and restore common sense to the environmental review and permitting process.”

In response to the interim final rule, the CEQ received more than 108,000 public comments, according to a document outlining the rule published today on the Federal Register. One such comment came from a coalition of environmental groups, expressing strong opposition to the rule last March.

NEPA “promotes sound and environmentally-informed decisionmaking by federal agencies, and it provides the primary way for the public to learn about and provide input regarding the impacts of federal actions on their lives,” the letter read. “The only certainty provided by the Interim Final Rule is less government transparency, more project delay, more litigation, less resilient infrastructure, and poor environmental and health outcomes for communities.”

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

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 © 2026. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

In an executive order issued on 7 January, the White House ordered the country’s withdrawal from 66 international agreements determined to be “contrary to the interests of the United States,” including two global efforts to combat climate change: the United Nations Framework Convention on Climate Change (UNFCCC) and the Intergovernmental Panel on Climate Change (IPCC).

The UNFCCC is a 1992 treaty that sets the legal framework for international cooperation to limit climate change. The IPCC is the United Nations organization that assesses and communicates climate science to global governments. 

The order will make the United States the only country in the world that does not participate in the UNFCCC.

 “As the only country in the world not a part of the UNFCCC treaty, the Trump administration is throwing away decades of U.S. climate change leadership and global collaboration.” 

“This is a shortsighted, embarrassing, and foolish decision,” Gina McCarthy, former EPA administrator under President Barack Obama, told E&E News. “As the only country in the world not a part of the UNFCCC treaty, the Trump administration is throwing away decades of U.S. climate change leadership and global collaboration.” 

McCarthy added that the U.S. withdrawal would limit the country’s ability to influence important decisions that impact the global economy, especially as other countries invest heavily in clean energy.

KD Chavez, executive director of the Climate Justice Alliance, an advocacy organization, said in a statement that the withdrawal “protects polluters while abandoning all of us, our livelihoods, and Mother Earth.”

“This move undermines treaty obligations, tribal sovereignty, and the global cooperation needed to survive the climate crisis,” Chavez said.

Others say the UFCCC is ineffective, and that leaving it could open new opportunities to cooperate with other countries to combat or mitigate climate change: “The framework convention is a joke,” George David Banks, Trump’s international climate adviser during his first term, told E&E News.

The UNFCCC has been criticized in the past for the ineffectiveness of its annual “conferences of the parties,” or COPs, as well as the influence of fossil fuel lobbyists at these meetings. 

 
Related

•  Read the Executive Order: Withdrawing the United States from International Organizations, Conventions, and Treaties that Are Contrary to the Interests of the United States
•  Trump Quits Pivotal 1992 Climate Treaty, in Massive Hit to Global Warming Effort
•  What is the UNFCCC and Why Is the U.S. Pulling Out?
•  Get Involved: AGU Science Policy Action Center
 

Because the Senate originally, and unanimously, advised President George H.W. Bush to join the UNFCCC in 1992, legal experts question whether the order to withdraw is constitutional, or whether the United States could rejoin in the future. 

The withdrawal from the IPCC also cuts the United States out of global climate science assessments. “Walking away doesn’t make the science disappear, it only leaves people across the United States, policymakers, and businesses flying in the dark at the very moment when credible climate information is most urgently needed,” Delta Merner, associate accountability campaign director for the Climate and Energy Program at the Union of Concerned Scientists, said in a statement. 

On his first day in office last year, Trump pulled the United States out of the Paris Agreement, a legally binding treaty setting long-term emissions goals, for a second time—an action that one United Nations report estimated would eliminate 0.1°C (0.18°F) of global progress on climate change by 2100. Withdrawing from the IPCC and UNFCCC leaves the United States further isolated from international cooperative efforts to limit climate change.

—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 © 2026. AGU. CC BY-NC-ND 3.0
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Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: AGU Advances

Understanding the paleoclimate of Mars is essential for gaining insights into Mars’ early history and atmospheric conditions. Such information is the key to learning why Mars shifted from a potentially warm, wet planet to the cold, dry desert we see now; whether climate change was gradual or catastrophic, thus informing how terrestrial planets evolve over billions of years.

Moreland et al. [2025] use an adapted lake energy balance model to investigate the connections between Martian geology and climate. By combining climate input from the Mars Weather Research & Forecasting general circulation model with geologic constraints from Curiosity rover observations, the study contributes to resolve the historic disconnect between the modeling results that suggest cold climate and the geologic evidence that liquid water was retained into Mars’ lakes. By concluding that relatively small lakes with a relatively limited water input and seasonal ice cover could retain seasonal liquid water for long times under Mars’ paleoclimate, the authors provide groundbreaking findings to inform climate models and enhance our understanding of conditions on early Mars.  

Citation: Moreland, E. L., Dee, S. G., Jiang, Y., Bischof, G., Mischna, M. A., Hartigan, N., et al. (2026). Seasonal ice cover could allow liquid lakes to persist in a cold Mars paleoclimate. AGU Advances, 7, e2025AV001891. https://doi.org/10.1029/2025AV001891

—Alberto Montanari, Editor-in-Chief, AGU Advances

Text © 2026. The authors. CC BY-NC-ND 3.0
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Sargassum has a bad reputation for washing up on shorelines, rotting on the beach, and creating a stinky mess. But this marine algae also functions as a habitat for many marine species, and new research published in Nature Geoscience indicates that its biomass has significantly declined where it once flourished: Since 2015, the amount of Sargassum in the northern Sargasso Sea has decreased by more than 90%. That change is likely caused by a reduced supply of healthy algae from the Gulf of Mexico, where water temperatures are rising, the researchers suggest.

“This is the only sea on Earth that has no physical boundaries.”

The floating brown algae known as Sargassum is found throughout the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico. (Other species exist in the Pacific.) A region of the subtropical North Atlantic Ocean is even named in its honor: the Sargasso Sea. Rafts of Sargassum measuring tens of meters wide and several kilometers long frequently form in the Sargasso Sea, and marine life ranging from crabs to shrimp to sea turtles takes refuge in the nooks and crannies afforded by its leaves and air-filled bladders.

The Sargasso Sea is a geographical anomaly when it comes to bodies of water—it’s bounded by ocean currents, not land. “This is the only sea on Earth that has no physical boundaries,” said Chuanmin Hu, an optical oceanographer at the University of South Florida in Tampa and the senior author of the new study.

Spotting Algae from Space

To better understand how Sargassum populations have shifted over time in the Sargasso Sea and beyond, Hu and his colleagues mined archival satellite data. The team focused on observations made from 2000 to 2023 with the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, which collects data in the near- and midinfrared ranges of the electromagnetic spectrum. That spectral coverage is important because Sargassum, like all other vegetation, strongly reflects near-infrared light; ocean water, on the other hand, does not.

“Sargassum has a different signal than the background ocean water,” said Hu.

The team, coled by Yingjun Zhang, Brian Barnes, and Deborah Goodwin, exploited that telltale sign to estimate the amount of algae present in various swaths of water. The researchers focused on six geographic regions that cumulatively spanned more than 40° in latitude and 90° in longitude. The team was able to detect Sargassum where the fractional areal coverage of the algae was as low as 1 part in 500. Typically, when Sargassum is present, there’s about 5 times that much of it in an average pixel, said Barnes, a satellite oceanographer at the University of South Florida in St. Petersburg.

The Northern Sargasso Sea, with Less Sargassum

The researchers found that Sargassum populations in the northern part of the Sargasso Sea have decreased dramatically since 2015—the satellite data revealed a roughly twelvefold drop in average biomass between 2000–2014 datasets and 2015–2023 datasets. (Measurements from the team’s shipboard surveys showed that Sargassum density declined by only about 50% over the same time period, but the team noted that those in situ data are sparse and potentially suffer from sampling bias.) If the satellite data are reflecting reality—and it’s likely that they are—that’s a substantial decrease in Sargassum, said Barnes. “There’s so much less now.”

At the same time, there’s been a proliferation of Sargassum in the so-called Great Atlantic Sargassum Belt. This 9,000-kilometer-wide swath of the ocean stretching from western Africa to the Gulf of Mexico saw an uptick in Sargassum beginning in 2011 that hasn’t abated. But it’s not as though the Great Atlantic Sargassum Belt is robbing the northern Sargasso Sea of its algae. The Great Atlantic Sargassum Belt is playing a role in the demise in the northern Sargasso Sea, but the largest changes are likely caused by shifting conditions in the Gulf of Mexico, the team surmised.

The agent that facilitates all of these connections? That’s ocean currents, said Zhang, an oceanographer at the Scripps Institution of Oceanography at the University of California, San Diego. The Sargasso Sea and the Gulf of Mexico may be thousands of kilometers apart, but they’re nonetheless linked by waters on the move.

Algae on a Journey

Satellite data have shown that the Gulf of Mexico is one of the key sources of Sargassum that ultimately ends up in the northern Sargasso Sea. The algae makes a journey that lasts several months: From the Gulf of Mexico, Sargassum hitches a ride on ocean currents—namely, the Loop Current and the Florida Current—before getting swept up in the Gulf Stream. It then makes its way along the East Coast of the United States before finally reaching the northern Sargasso Sea.

But sea surface temperatures have been rising in the Gulf of Mexico in recent years, often reaching more than 30°C in the summertime. Sargassum prefers temperatures ranging from 23°C to 28°C, and heat-stressed algae are less likely to survive the monthslong journey to the northern Sargasso Sea, said Hu. “During the long-distant transport, most of it will die.”

“You have a one-two punch.”

That makes sense, said William Hernandez, an oceanographer at the University of Puerto Rico–Mayaguez who was not involved in the research. Sargassum stressed by high temperature is less likely to take up nutrients and grow adequately, he said. “It’s the same thing that you see in terrestrial vegetation.”

In addition to heat stress, Sargassum in the Gulf of Mexico is also likely suffering from a lack of nutrients. That’s because the plentiful Sargassum in the Great Atlantic Sargassum Belt is gobbling up necessary compounds like phosphorus and sulfates, said Hernandez. So when currents off the coast of South America and in the Caribbean sweep water into the Gulf of Mexico, they’re transporting something that’s essentially already been picked over, he said. “By the time those waters reach that area, they’ve already been depleted of their nutrients.”

The combined effects of heat stress and limited nutrients really wallop Sargassum populations, said Hernandez. “You have a one-two punch.” There might well be ecological repercussions to having less Sargassum in the northern Sargasso Sea, the team suggests. Fish and other creatures rely on Sargassum for habitat, so less algae could translate into measurable impacts on other animals. Collecting in situ animal data in the Sargasso Sea will help answer that question, said Hu. “There should be impacts on other animals. Is that the case?”

—Katherine Kornei (@KatherineKornei), Science Writer

Citation: Kornei, K. (2026), The northern Sargasso Sea has lost much of its namesake algae, Eos, 107, https://doi.org/10.1029/2026EO260014. Published on 8 January 2026. Text © 2026. 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

Heat waves are becoming commonplace, and so too is high humidity, which can strain the electrical grid, hurt the economy, and endanger human health. But the global prevalence of record-breaking humidity events, some of which approach the physiological limit of what humans can safely handle—and all of which go beyond local expectations and adaptations—has not been widely studied.

To remedy that oversight, Raymond et al. used data from the European Centre for Medium-Range Weather Forecasts Reanalysis 5 (ERA5) and several other sources to establish the most intense humid heat that has occurred in recent years across the globe. They then used several climate models to estimate where instances of even more severe humid heat are most likely to occur in the future.

Relative to the local climate, humid heat can be most extreme in the Middle East and North Africa, with tropical regions coming in a close second, the researchers found. In these locales, the wet-bulb temperature (a measure of humid heat) is capable of reaching 4–5 standard deviations above the average for the warm season. The Middle East and North Africa are also among the regions that experience the longest stretches of humid heat, sometimes lasting 20 or more days.

Estimates of overall humid heat likelihood are very sensitive to a few extremely hot, humid days, the researchers found. In many locations, removing a single outlier led statistical models to predict fivefold fewer hot, humid days in the future. The finding highlights the need for accurate observational data, the researchers write.

Humid heat is particularly dangerous when it comes in spurts, offering areas little relief for concentrated periods. In the tropics, three quarters of the days when the wet-bulb temperature was in the top 5% occurred in only a quarter of the years included in the study. This is likely largely because El Niño heightens both atmospheric temperature and moisture levels, so record-setting days in the tropics tend to cluster in years when this weather pattern is active.

The researchers note that 2023 was a banner year for humid heat, with 23 different regions setting records. That’s entirely because of climate change, the researchers’ work suggests: Otherwise, no records would have been broken. (AGU Advances, https://doi.org/10.1029/2025AV001963, 2025)

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

Citation: Sidik, S. M. (2026), Temperatures are rising, but what about humidity?, Eos, 107, https://doi.org/10.1029/2026EO260020. Published on 8 January 2026. Text © 2026. 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 universe never fails to surprise. Take TOI-561 b, an Earth-sized exoplanet that circles its star on an orbit more than 30 times smaller than Mercury’s.

Despite being blasted by radiation to the point that its rocky surface is likely molten, TOI-561 b still seems to retain a thick atmosphere. This discovery, reported in The Astrophysical Journal Letters, shows that even highly irradiated planets—whose atmospheres should have been eroded long ago—can remain enshrouded in gas for billions of years.

Lava World

When it comes to constellations, Sextans (the Sextant) is largely unremarkable; its brightest stars can’t even be seen with the naked eye from a large city. But there’s a star in Sextans that is home to a miniature solar system: TOI-561, roughly twice as old as the Sun, has four planets orbiting it. And the innermost of those planets, known as TOI-561 b, holds the special honor of being what’s called an ultrashort-period exoplanet. That’s a world no larger than twice the radius of Earth that whips around its host star in 1 day or less.

“We do not expect that an atmosphere can survive.”

Ultrashort-period exoplanets are rare—only several dozen are known to exist—and they’re extreme: They orbit so close to their host stars that they typically have dayside temperatures above the melting point of rock, leading researchers to dub them “lava worlds.” Ultrashort-period exoplanets are also planets on a journey—it’s thought that they formed farther away from their stars and migrated inward over time.

Many ultrashort-period exoplanets observed to date also don’t have atmospheres. That makes sense, said Rafael Luque, an astrophysicist at the Institute of Astrophysics of Andalusia in Granada, Spain, not involved in the new research. These extreme worlds are literally being irradiated by their host stars, he said. “We do not expect that an atmosphere can survive.”

A Puffed-Up World?

Earlier observations revealed both the size and mass of TOI-561 b. Taken together, those data suggest an anomalously low density for the planet, roughly 4.3 grams per cubic centimeter. (Earth’s average density, for comparison, is about 5.5 grams per cubic centimeter.)

There are several explanations for that finding, said Nicole Wallack, an astronomer at Carnegie Science in Washington, D.C., and a member of the research team. For instance, TOI-561 b might lack an iron core. But a more likely scenario is that it’s a puffed-up planet that appears larger and therefore less dense than it actually is, said Wallack.

And a thick atmosphere is the most logical culprit for a puffed-up exoplanet, she explained. “It could have an atmosphere that’s making the planet appear larger in radius but isn’t influencing its mass as much.”

To test that idea, Wallack and her colleagues, led by Johanna Teske, an astronomer at Carnegie Science, recently observed TOI-561 b and its host star using the James Webb Space Telescope. The researchers collected near-infrared observations of four orbits of the planet, each of which lasted only about 11 hours.

“Atmospheres are much better than solid rocks are at transporting heat.”

For this new study, the team focused on data collected around the time of so-called secondary eclipse. That’s when a planet passes behind its star, as seen from a telescope’s perspective. By comparing observations recorded when the star and planet are both visible to those recorded when just the star is visible, it’s possible to home in on just the signal from the planet, said Wallack. For TOI-561 b, the team divided that planet signal into seven near-infrared wavelength bins and looked at how the light was distributed as a function of wavelength.

That investigation allowed the team to estimate the approximate temperature of TOI-561 b: about 1,700–2,200 K. That’s significantly cooler than the roughly 3,000 K expected on the basis of the temperature of the star and TOI-561 b’s distance from it. “The planet appears to be colder than we would have expected,” said Wallack.

An atmosphere is the best explanation for that discrepancy, Teske and her colleagues proposed. The presence of an atmosphere would allow heat to be redistributed away from a planet’s warmer dayside and toward its cooler nightside. That process of heat distribution is much more efficient than relying on rocks to do the same thing, said Wallack. “Atmospheres are much better than solid rocks are at transporting heat.”

TOI-561 b might not be a complete outlier when it comes to having an atmosphere. After all, a handful of other ultrashort-period exoplanets, such as 55 Cancri e, are believed to be enshrouded in gas.

Hunting for Molecules

After analyzing the Webb observations, the researchers modeled signals that would be expected from an atmosphere containing varying proportions of molecules such as water, carbon dioxide, and carbon monoxide. They found that their data were no more consistent with one model than another. The relatively wide spectral binning that the team adopted—just seven data points over a range of roughly 2.7–5.1 micrometers—may have precluded detecting any molecule-specific features, the team concluded.

Even though the composition of TOI-561 b’s atmosphere remains inconclusive, there’s good evidence that it exists, said Michael Zhang, an astronomer at the University of Chicago not involved in the research. “I believe that there is an atmosphere.”

And that atmosphere is most likely composed of material outgassed from TOI-561 b’s molten surface. That inference can guide logical follow-on work modeling the planet’s atmosphere, said Zhang. “You can test compositions that you expect would be outgassed from the magma ocean.”

Analyzing TOI-561 b’s nightside signal—something that’s possible with the researchers’ current dataset—will also be important, said Zhang. It’s a tough measurement to make, but because atmospheres are good at redistributing heat, he explained, even the side of TOI-561 b facing away from its star should be detectable. “The nightside should be warm.”

—Katherine Kornei (@KatherineKornei), Science Writer

Citation: Kornei, K. (2026), A “lava world” unexpectedly hosts an atmosphere, Eos, 107, https://doi.org/10.1029/2026EO260019. Published on 7 January 2026. Text © 2026. 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.

An fascinating case study from the 24 June 2025 Granizal landslide in Medellín, Colombia, which killed 27 people and destroyed 50 homes, shows demonstrates that it is not just the urban poor that are exposed to landslides.

That urban areas can be subject to high levels of landslide risk is well-established – commonly cited examples are Hong Kong (which has a huge programme to manage the risk), Sao Paolo and Medellín, amongst other places. The well-established pattern is that it is the urban poor that have the highest levels of risk, being forced to live on slopes on the margins of the conurbation, often with poor planning and low levels of maintenance of, for example, drainage systems.

A fascinating open access paper (Ozturk et al. 2025) has just been published in the journal Landslides that suggests that this pattern might be beginning to change under the impacts of climate change. The paper examines the 24 June 2025 Granizal landslide in Medellín, Colombia, which killed 27 people and destroyed 50 houses. I wrote about this landslide at the time, including this image of the upper part of the landslide:-

The main body of the 25 June 2025 landslide at Granizal in Colombia. Still from a video posted to Youtube by Cubrinet.

The location of the headscarp of the Granizal landslide is [6.29587, -75.52722].

The analysis of Ozturk et al. (2025) shows that this is a 75,000 cubic metre failure with a source area length of 143 m and a width of 50 m. The landslide was triggered by rainfall over a 36 hour period.

The authors’ analysis suggests that the landslide occurred on terrain that is steep even by the standards of Medellín, and at a comparably high elevation for the city. They have then looked at the distribution of income tax bands for the city according to both elevation and slope angle:-

Hillslope angle (a) and elevation (b) of the built up area in Medellín, categorized by utility tax, known as Strata, which determines the socio-economic status of different neighbourhoods. For example, the utility tax decreases as the categories get lower. Hillslope angle increases generally towards poorer categories. Figure from Oztuk et al. (2025), with the caption lightly edited.

The diagram shows that in Medellín, the poorest people live on the steepest slopes, and thus (at the first order) are more at risk of landslides. People with higher income levels tend to live on areas with a lower slope angle – the more affluent you are, the lower your landslide risk. However, this pattern reverses for those in the highest tax band (i.e. the richest). Those people live on steeper slopes (although not as steep as for the poorest people).

A similar pattern emerges for elevation, although the pattern is weaker. But compare Utility tax categories 5 and 6 for example – the richest people migrate to higher elevations.

This probably represents a desire by the most affluent to live in locations with the best views and in which they can have larger plots of land. A similar pattern is seen elsewhere – for example, property prices in The Peak in Hong Kong are very high.

It has been possible to live in these higher risk locations because of good identification of hazards for those that can afford it, the use of engineering approaches to mitigate the hazard and good maintenance of drains. These options are available to those with money, who live in “formal neighbourhoods” rather than unplanned communities. Of course, as Ozturk et al. (2025) remind us, the vulnerability of these communities is still much lower than that of the poor.

But Ozturk et al. (2025) make a really important point:-

“…we should not forget that climate change is gradually intensifying and may soon render the design criteria used for planning formal neighbourhoods obsolete. Hence, our concluding message is that future rainfall changes may also lead to catastrophic landslide impacts in formally planned urban neighbourhoods, challenging the assumption that only informal settlements are at high risk.”

The vulnerability of the poorest communities means that this is where the highest risk will continue to be located, and this is where the greatest levels of loss will occur. But our rapidly changing environment means that even more affluent communities are facing increasing levels of risk.

Reference

Ozturk, U., Braun, A., Gómez-Zapata, J.C. et al. 2025. Urban poor are the most endangered by socio-natural hazards, but not exclusively: the 2025 Granizal Landslide case. Landslides. https://doi.org/10.1007/s10346-025-02680-y

Return to The Landslide Blog homepage Text © 2026. 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: Global Biogeochemical Cycles

The Atlantic Meridional Overturning Circulation (AMOC) is the system of currents responsible for shuttling warm water northward and colder, denser water to the south. This “conveyor belt” process helps redistribute heat, nutrients, and carbon around the planet.

During the last ice age, occurring from about 120,000 to 11,500 years ago, millennial-scale disruptions to AMOC correlated with shifts in temperature, atmospheric carbon dioxide (CO2), and carbon cycling in the ocean—as well as changes in the signatures of carbon isotopes in both the atmosphere and the ocean. At the end of the last ice age, a mass melting of glaciers caused an influx of cold meltwater to flood the northern Atlantic, which may have caused AMOC to weaken or collapse entirely.

Today, as the climate warms, AMOC may be weakening again. However, the links between AMOC, carbon levels, and isotopic variations are still not yet well understood. New modeling efforts in a pair of studies by Schmittner and Schmittner and Boling simulate an AMOC collapse to learn how ocean carbon storage, isotopic signatures, and carbon cycling could change during this process.

Both studies used the Oregon State University version of the University of Victoria climate model (OSU-UVic) to simulate carbon sources and transformations in the ocean and atmosphere under glacial and preindustrial states. Then, the researchers applied a new method to the simulation that breaks down the results more precisely. It separates dissolved inorganic carbon isotopes into preformed versus regenerated components. In addition, it distinguishes isotopic changes that come from physical sources, such as ocean circulation and temperature, from those stemming from biological sources, such as plankton photosynthesis.

Results from both model simulations suggest that an AMOC collapse would redistribute carbon throughout the oceans, as well as in the atmosphere and on land.

In the first study, for the first several hundred years of the model simulation, atmospheric carbon isotopes increased. Around year 500, they dropped sharply, with ocean processes driving the initial rise and land carbon controlling the decline. The decline is especially prominent in the North Atlantic in both glacial and preindustrial scenarios and is driven by remineralized organic matter and preformed carbon isotopes. In the Pacific, Indian, and Southern Oceans, there was a small increase in carbon isotopes.

In the second study, model output showed dissolved inorganic carbon increasing then decreasing, causing the inverse changes in atmospheric CO2. In the first thousand years of the model simulation, this increase in dissolved inorganic carbon can be partially explained by the accumulation of respired carbon in the Atlantic. The subsequent drop until year 4,000 is primarily driven by a decrease in preformed carbon in other ocean basins. (Global Biogeochemical Cycles, https://doi.org/10.1029/2025GB008527 and https://doi.org/10.1029/2025GB008526, 2025).

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

Citation: Owen, R. (2026), What could happen to the ocean’s carbon if AMOC collapses, Eos, 107, https://doi.org/10.1029/2026EO260016. Published on 6 January 2026. Text © 2026. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

Today, top appropriators in the U.S. Senate and House of Representatives released a three-bill appropriations package for fiscal year 2026 (FY26) that largely rejects drastic cuts to federal science budgets that President Trump proposed last year. The “minibus” package, negotiated and agreed upon by both political parties, outlines a budget that preserves most, but not all, funding for key science programs related to space, weather, climate, energy, and the environment across multiple agencies.

“This is a fiscally responsible package that restrains spending while providing essential federal investments that will improve water infrastructure in our country, enhance our nation’s energy and national security, and spur scientific research necessary to maintain U.S. competitiveness,” Susan Collins (R–ME), chair of the Senate Appropriations Committee, said in a statement.

In May 2025, President Trump released a budget request to Congress that proposed slashing billions of dollars in federal science funding. However, during the many rounds of meetings throughout the year, appropriators in both chambers and on both sides of the aisle seemed disinclined to follow the proposed budget, including when it came to funding for climate research, clean energy initiatives, environmental protections, and other topics that run counter to administration priorities.

 
Related

•  Dig into the details: Three Bill Package
•  Statement and Summaries from the Majority (GOP)
• Statement and Summaries from the Minority (Democrats)
•  Review the President’s Budget Request
•  Get Involved: AGU Science Policy Action Center
 

This new three-bill package follows suit in rejecting many of the president’s more drastic cuts to science programs.

“This package rejects President Trump’s push to let our competitors do laps around us by slashing federal funding for scientific research by upwards of 50% and killing thousands of good jobs in the process,” Vice Chair Senator Patty Murray (D–WA) said in a statement. “It protects essential funding for our public lands, rejects steep proposed cuts to public safety grants that keep our communities safe, and boosts funding for key flood mitigation projects.”

Here’s how some Earth and space science agencies fare in this package:

• Department of Energy (DOE) Non-Defense: $16.78 billion, including $8.4 billion for its Office of Science, $3.1 billion for energy efficiency and renewable energy programs, and $190 million for protecting the nation’s energy grids.
• Environmental Protection Agency (EPA): $8.82 billion, preserving funding to state-level programs that protect access to clean water, drinking water, and air. The bill also retains funding for the Energy Star energy efficiency labelling program and increases funding to state and Tribal assistance grant programs.
• NASA: $24.44 billion, including $7.25 for its science mission directorate, which would have seen a 47% decrease under the President’s budget request. The bills maintain funding for 55 missions that would have been cut, as well as for STEM engagement efforts and Earth science research that similarly would’ve been cut. It also increases spending for human exploration.
• National Institute of Standards and Technology (NIST): $1.847 billion, including funds to advance research into carbon dioxide removal.
• National Oceanic and Atmospheric Administration (NOAA): $6.171 billion, including $1.46 billion to the National Weather Service to improve forecasting abilities and boost staffing. The budget also earmarks funds to preserve weather and climate satellites, and maintain climate and coastal research.
• National Park Service (NPS): $3.27 billion, with enough money to sustain FY24 staffing levels at national parks.
• National Science Foundation (NSF): $8.75 billion, including $7.18 billion for research-related activities. That would support nearly 10,000 new awards and more than 250,000 scientists, technicians, teachers, and students.
• U.S. Forest Service (USFS): $6.13 billion, with just under half of that put toward wildfire prevention and management. Funded programs not related to wildfire prevention include forest restoration, forest health management, hazardous fuels reduction, and repurposing unnecessary roads as trails.
• U.S. Geological Survey (USGS): $1.42 billion, including money to maintain active satellites and topographical mapping programs.

This is the latest, but not the last, step in finalizing science funding for FY26. The bills now head out of committee to be voted upon by the full chambers of the Senate and House, reconciled between chambers, and then signed by the president.

—Kimberly M. S. Cartier (@astrokimcartier.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 © 2026. 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.

Three hundred years ago, the central United States was a land of wetlands—more than 150 million hectares of them. All that water made the region highly attractive to farmers, who, over time, converted most of it into agricultural land.

For the wetlands that remain, protections secured by the Clean Water Act are often the only thing preventing wetland conversion or development, especially when state protections are weak, said Kylie Wadkowski, a landscape ecohydrologist and doctoral candidate at Stanford University. 

With wetlands, “you actually can’t do whatever you want,” said Elliott White Jr., a coastal socioecosystem scientist at Stanford University. “That’s how this Sackett case came about.”

The Supreme Court’s 2023 Sackett v. EPA decision ruled in favor of two landowners backfilling a lot containing wetlands. The decision changed the definition of the term “waters of the United States”—which is used in the Clean Water Act—to exclude wetlands without continuous surface connections to larger, navigable bodies of water. In November 2025, the Trump administration’s EPA proposed to set new rules for water regulations that may be even looser than the updated Sackett definition.

According to research by Wadkowski and White presented on 15 December 2025 at AGU’s Annual Meeting in New Orleans, the changing definition will leave millions of hectares of wetlands unprotected and more vulnerable to development. 

Wadkowski and White are the first to analyze wetland protections in detail on a nationwide scale, said Adam Ward, a hydrologist at Oregon State University who was not involved in the research. “This represents a huge advance in understanding what is being protected and what is losing protections,” he said.

What Will Happen to Wetlands?

Wadkowski and White found that under Sackett, 16.4 million hectares of wetlands, an area about the size of Wisconsin, are either unprotected or have undetermined status. Under the EPA’s newest proposed rule, that number could increase; the proposed rule contains many subjective and ill-defined terms that could be interpreted by regulators to mean even more wetlands lose protections, Ward said.

The approach the researchers took—using the available wetland, stream, and land conversion data with spatial modeling—was “incredibly logical,” Ward said. “They’re using machine learning tools, using the information we have to try and gap-fill and create the most comprehensive analysis that they can, and that’s a huge step in the right direction.”

Rates of vulnerability were not consistent across the United States. A breakdown of protections based on land management categories showed that 43.5% of wetlands on lands managed by tribes was protected under Sackett, compared to the national average of 66%.

Wetlands in the Great Plains states North Dakota, South Dakota, Nebraska, Montana, and Minnesota were the least protected. This area of the country is often called the “prairie pothole” region because many of its wetlands are depressions in the landscape fed by groundwater and disconnected from larger surface water bodies. Under Sackett, these geographically isolated wetlands rely entirely on state-level protections, which are also often weaker in agricultural regions, Wadkowski said.

“The economic pressure and agricultural [conversion] happens a lot more in the Plains states,” she said. “And those are also the states that have less state level protections.”

With a rule that “emphasizes overland [surface] flow and connection to streams and rivers, it shouldn’t surprise us at all that it excludes wetlands that aren’t wet because of overland [surface] flow,” Ward said.

Wadkowski plans to continue to evaluate how various legal frameworks might affect wetland conversion rates in the future by comparing their estimates of protected wetlands under Sackett and the new EPA proposal with past data on wetland conversion rates under previous definitions of “waters of the United States.”

Informing Policy

To best protect wetlands, policymakers should ensure their policies line up with the available science, White said. 

Part of that strategy includes acknowledging that wetlands that are not connected to larger bodies of water year-round via surface water and therefore may not be protected under the Sackett decision may still be connected to broader water systems through groundwater, Wadkowski said. “Think about water bodies as not just on the surface.”

“Policymakers need to more thoughtfully engage with the scientific community for a more clear understanding of what a wetland is and what wetlands actually need.”

The Sackett decision and the new EPA proposal do not reflect the scientific consensus, White said. “Policymakers need to more thoughtfully engage with the scientific community for a more clear understanding of what a wetland is and what wetlands actually need.” Scientists, too, need to better engage with policymakers, he added.

For example, said Ward, part of the reason that wetland rule frameworks are so contentious is that none have yet been informed by enough clear, comprehensive science to make enforcement efficient or practical. “We have heaps of scientific understanding, but the scientific community writ large has not been invited to formally weigh-in on how to design a rule that reflects our understanding,” he wrote in an email.

In a presentation on 15 December at AGU’s Annual Meeting, Ward made the case for a new, large-scale U.S. headwater stream monitoring network, which would help reduce some of the uncertainty inherent in wetland regulations. “If you don’t understand the stream network, you can’t possibly understand the wetland protections,” he said.

Scientific engagement, however, has been made more difficult by the courts, according to Ward: Within the past 5 years, the Supreme Court has begun to invoke the major questions doctrine, which preserves major rulemaking on matters of environmental regulations for Congress, giving agencies like the EPA less incentive to seek input from scientists. 

“In parallel with our advances in understanding [wetland science] is a court system that is essentially cutting scientists out of the loop,” Ward said.

The public comment period for the EPA’s newest proposed rule closes on 5 January.

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

Citation: van Deelen, G. (2026), After Sackett, a Wisconsin-sized wetland area is vulnerable, Eos, 107, https://doi.org/10.1029/2026EO260018. Published on 5 January 2026. Text © 2026. 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

Single-celled algae in the ocean known as coccolithophores play an important role in the marine carbon cycle when they take up bicarbonate from seawater to build their shells. Coccolithophore numbers have been increasing globally in recent years, meaning their influence is growing, even as scientists still don’t fully understand the factors driving their explosive growth. One explanation could be changes to the alkalinity of ocean water, specifically, greater amounts of bicarbonate available for the tiny creatures to use.

For more information on how coccolithophores grow and flourish, Zhang et al. looked to the last time the phytoplankton surged in number, between 300,000 and 500,000 years ago. Using fossilized coccolithophore morphology and examining carbon isotope ratios, the authors constructed models that allowed them to pick apart the ingredients for coccolithophore success.

Comparisons of inorganic to organic carbon ratios in the shells, as well as comparisons of photosynthesis and calcification rates revealed by carbon isotope ratios, showed a large increase in calcification linked to greater bicarbonate uptake. Though increasing alkalinity was likely a factor in the coccolithophores’ increased growth, it doesn’t explain all of it, the authors say. Instead, greater nutrient availability allowed coccolithophore populations to swell, both by giving them more food to use and by allowing them to move to shallower depths where there was more sunlight for photosynthesis.

The findings have implications for the present day, as we see marine phytoplankton numbers shifting alongside changes in ocean chemistry. Previous works focused on the change in seawater alkalinity and pH. But more information on how nutrient availability influences coccolithophore growth is needed, the authors conclude, especially in light of proposed geoengineering schemes that could shift the types of nutrients available. (AGU Advances, https://doi.org/10.1029/2024AV001609, 2025)

—Nathaniel Scharping (@nathanielscharp), Science Writer

Citation: Scharping, N. (2026), How a move to the shallows 300,000 years ago drove a phytoplankton bloom, Eos, 107, https://doi.org/10.1029/2026EO260010. Published on 5 January 2026. Text © 2026. 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.

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

Las olas de calor marinas describen casos de aguas extraordinariamente cálidas que pueden permanecer en la superficie del océano durante meses. Al igual que las olas de calor que experimentamos en tierra, las olas de calor marinas pueden alterar la química ambiental y estancar los procesos biológicos. Mientras que las pérdidas catastróficas de megafauna son indicadores evidentes de un sistema de estrés, los investigadores han comenzado a recopilar datos suficientes para entender cómo los organismos microbianos en la base de las redes tróficas oceánicas están respondiendo a las olas de calor.

Un nuevo estudio publicado en Nature Communications presenta una década de mediciones que documentan dos olas de calor sucesivas en el noreste del Océano Pacífico. El equipo interdisciplinario de autores de este artículo utilizó una combinación de una boya robótica autónoma, un crucero oceanográfico y datos satelitales para entender cómo las comunidades microbianas de la región se reorganizaron en respuesta a estos eventos extremos.

Los investigadores descubrieron que la producción de materia orgánica incrementó en la superficie del océano durante las olas de calor, pero las partículas ricas en carbono no se hundieron, ni flotaron, más bien, se quedaron en su lugar.

La bomba biológica de carbono

Fitoplancton—diminutos microbios fotosintetizadores—activan la bomba biológica de carbono. Al usar la luz solar y el dióxido de carbono (CO2) para crecer, el fitoplancton extrae carbono de la atmósfera y lo incorpora al ciclo del carbono océanico. El zooplancton se alimenta en los extensos campos con estos organismos similares a plantas, transportando carbono a zonas más profundas de la columna de agua en forma de pellets fecales y pedazos de plancton a medio comer. Eventualmente, algunas de estas partículas se sumergen lo suficientemente como para alimentar los ecosistemas de las profundidades oceánicas.

“La capacidad del océano para capturar carbono depende de los microbios en la base de la red trófica.”

Esta bomba de carbono representa un amortiguador globalmente relevante frente a los impactos del cambio climático, ya que el océano absorbe aproximadamente la cuarta parte del CO2 emitido por la actividad humana. Algunas estimaciones sugieren que nuestras concentraciones atmosféricas actuales de CO2, podrían incrementar hasta un 50% si la bomba biológica de carbono dejará de transportar carbono hacia las profundidades del océano.

“La capacidad del océano para capturar carbono depende de los microbios en la base de la red trófica, entonces es muy importante que nosotros comencemos a entender cuáles son los impactos de las olas de calor marinas en las comunidades microbianas”, explicó Mariana Bif, autora principal del nuevo estudio. Bif es profesora asistente en la Universidad de Miami y anteriormente fue investigadora en el Instituto de Investigación del Acuario de la Bahía de Monterey, o MBARI por sus siglas en inglés.

Cuando la red trófica se enreda

En ambas olas de calor marinas rastreadas en el estudio, los investigadores encontraron que la bomba de carbono biológica mostraba señales de sobrecalentamiento. Las partículas ricas en carbono se quedaron estancadas aproximadamente a los 200 metros (660 pies) debajo de la superficie, pero durante las dos olas de calor, distintos mecanismos causaron esta acumulación.

La primera ola de calor incluida en el estudio empezó en el 2013, cuando vientos inusualmente débiles sobre el Pacífico no lograron devolver el aire cálido del verano hacia el territorio continental de los Estados Unidos. La ola de calor, apodada “the Blob” fue noticia cuando las aguas cálidas, estancadas y deficientes en oxígeno provocaron mortandades masivas de fauna en todos los rincones del Pacífico antes de disiparse en 2015.

En 2019, la nubosidad irregular sobre el océano y  prepararon el escenario para que otra ola de calor barriera con el noreste del Pacífico. Esta segunda ola de calor elevó nuevamente las temperaturas y pasó a conocerse como “the Blob 2.0”.

Bif y sus coautores encontraron que durante ambas olas de calor, la comunidad microbiana marina experimentó un cambio en sus “mandos intermedios”.

Dentro de los primeros años del Blob, las condiciones físicas y químicas favorecieron a especies más pequeñas de fitoplancton, lo que a su vez favoreció a un nuevo grupo de alimentadores zooplanctónicos. Esta discreta red trófica, eventualmente creó una capa oceánica llena de partículas orgánicas que eran demasiado ligeras para hundirse en las aguas más densas de las profundidades.

Durante el Blob 2.0, las concentraciones de las partículas de materia orgánica fueron aún más altas, pero el incremento no provino totalmente de la producción primaria. Esta vez las condiciones favorecieron a especies frugales. Los organismos oportunistamente capaces de alimentarse de detritos y de materia orgánica de menor calidad se volvieron más predominantes, mostrando que el sistema estaba ciclando y reciclando carbono para mantenerlo en la parte superior de la columna de agua. Dentro de esta comunidad, los parásitos prosperaron, y organismos (incluido un grupo de radiolarios) que nunca antes se habían observado en el noreste del Pacífico comenzaron a aparecer regularmente.

Midiendo en medio de la nada

La gama de tecnología utilizada en el estudio lo distingue de esfuerzos previos para catalogar los efectos de las olas de calor marinas

“Ahora nosotros estamos entrando en una era de ‘big data’ en la biogeoquímica oceánica, mientras que antes estábamos limitados a lo que podíamos recolectar desde los barcos.”

“Ahora nosotros estamos entrando en una era de ‘big data’ en la biogeoquímica oceánica, mientras que antes estábamos limitados a lo que podíamos recolectar desde los barcos,” dijo Stephanie Henson, científica principal en el Centro Nacional de Oceanografía en Southampton (NOC Southampton, por sus siglas en inglés), Reino Unido. Henson no participó en el estudio.

Henson explicó que las boyas autónomas y otros sistemas de monitoreo avanzado están permitiendo a los investigadores trabajar con un set de datos que se extiende más allá de la duración de un crucero oceanográfico.

“La gente ha estado estudiando las respuestas a las olas de calor marinas en sistemas como los arrecifes de coral, etcétera”, dijo Henson, explicando que los investigadores han observado que no todas las respuestas biológicas son iguales de una ola de calor marina a otra. Sin embargo, señaló que este estudio fue el primero que demuestra que los flujos de carbono en el océano, también presentan respuestas complejas a las olas de calor marinas.

Para revisar los signos vitales del Pacífico antes, durante y después de cada una de las olas de calor, los investigadores recurrieron a la Red Global de Biogeoquímica Oceánica (GO-BGC, por sus siglas en inglés). Los instrumentos GO-BGC son un subconjunto de la red Argo, una red global de miles de boyas robóticas autónomas. Cada boya se desplaza libremente con las corrientes oceánicas, monitoreando el pH, la salinidad, la temperatura y otros parámetros

Mariana Bif se prepara para desplegar una boya GO-BGC en la Bahía de Bengala. La boya derivará libremente en las corrientes oceánicas a aproximadamente 1.000 a 2.000 metros de profundidad, regresando a la superficie cada 10 días para enviar datos sobre la temperatura, salinidad y química oceánica, vía satélite, a los investigadores en tierra. (El océano Índico no fue parte del nuevo estudio, pero Bif utilizó boyas GO-BGC en el Pacífico para realizar la investigación.) Créditos: Sudheesh Keloth, Julio, 2025

A pesar de todo lo que pueden hacer, las boyas no son capaces de recolectar muestras microbianas. Para esto, en lugar de que Bif buscara la data, la data llegó a Bif.

Steven Hallam, microbiólogo de la Universidad de Columbia Británica y coautor en el nuevo estudio, se puso en contacto con Bif después de leer una entrevista con ella sobre su trabajo en olas de calor marinas. Él tenía la corazonada de que las muestras de ADN planctónico almacenadas en el refrigerador de su laboratorio podrían ser de ayuda para la investigación de Bif sobre el ciclo del carbono en el océano. Científicos del grupo de laboratorio de Hallam habían publicado previamente investigaciones sobre comunidades bacterianas en la misma región, usando muestras recolectadas durante los cruceros oceanográficos a lo largo del transecto Line P frente a la costa de Columbia Británica.

Después de un intercambio por correo electrónico, el grupo de laboratorio de Hallam analizó las muestras, expandiendo el análisis de las bacterias a la composición de la comunidad entera, lo que resultó en una contribución significativa al estudio de Bif.

Mientras la historia de cómo el ADN planctónico vino a Bif es un testimonio del poder entre la comunicación y colaboración en la ciencia, Henson notó que los transectos de la Line P, no necesariamente se superponen espacialmente con las regiones de mayor impacto de las olas de calor marinas, y combinar los conjuntos de datos de diferentes escalas (como los datos obtenidos en barcos y los datos de flotadores autónomos) debería hacerse cautelosamente.

Además, Henson añadió, “Es lo mejor que podemos hacer por el momento”

Incertidumbres persistentes

Respecto a las investigaciones futuras, Bif está involucrada en algunos nuevos proyectos explorando regiones marinas desoxigenadas, pero dijo: “Mi enfoque siempre es en los flotadores BGC-Argo”.

Bif indicó que será interesante observar los datos de BGC-Argo desde los flotadores que están en medio de la ola de calor marina afectando actualmente el Pacífico Norte. Esa ola de calor ya está mostrando señales de desaceleración, aunque los científicos dicen que probablemente permanecerá durante el invierno.

“No estoy seguro de si esto va a tener el alcance que tuvieron algunas de las olas de calor marinas anteriores en la región”, dijo Nick Bond, quien no estuvo involucrado en esta investigación pero estudió las olas de calor marinas como parte de su rol anterior como climatólogo del estado de Washington. Ahora él es investigador sénior en la Universidad de Washington.

“Lo que no medimos, no podemos entenderlo. Necesitamos más inversiones para monitorear el océano.”

Bond añadió que mientras haya “evidencia tentativa” de que el calentamiento climático puede estar incrementando la frecuencia de olas de calor marina en el Pacífico, aún hay mucho más por aprender antes de que los científicos puedan pronosticar con precisión cómo se comportarán en el futuro.

Mientras tanto, otra incógnita que se avecina para este campo de investigación se está desarrollando nuevamente en tierra firme.

“Hay un poco de incertidumbre en la comunidad porque al momento, para el programa global Argo, Estados Unidos contribuye aproximadamente con la mitad de los flotadores que se despliegan”, dijo Henson, aludiendo su preocupación a los recortes presupuestarios recientes en Estados Unidos. Sin embargo, ella explicó que otros países están intensificando sus contribuciones para mantener a flote el programa Argo.

“Lo que no medimos no podemos entenderlo. Necesitamos más inversiones para monitorear el océano” dijo Bif.

—Mack Baysinger (@mack-baysinger.bsky.social), Escritor de ciencia

This translation by translator (@Cecilia Ormaza) was made possible by a partnership with Planeteando y GeoLatinas. Esta traducción fue posible gracias a una asociación con Planeteando and GeoLatinas.

Text © 2026. 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.

Yukon Geological Survey

Contributors: Derek Cronmiller, Theron Finley, Panya Lipovsky, Jan Dettmer

A guest post featuring images and a commentary of landslides in Yukon Territory in Canada triggered by the 6 December 2025 M=7.0 Hubbard Glacier Earthquake.

The 6 December 2025 Mw=7.0 Hubbard Glacier Earthquake in the St. Elias Mountains of Yukon caused widespread mass wasting activity in an area near Mt. Logan, Canada. On 12 December 2025, the Yukon Geological Survey completed an overview flight of the area to collect photographs and document seismically induced activity in the region. Based on the preliminary USGS finite fault model, the earthquake rupture appears to have been shallow, with approximately 2 m of slip occurring at ~6 km depth but no evidence of earthquake surface rupture was identified. However, we documented extensive surface effects including more than 200 landslides, many snow and ice avalanches, and widespread damage to glaciers throughout the area.

View southwest towards Mt King George. Snow avalanche and serac collapse scars are visible on the ridge in the foreground, large rock avalanche scars on the NE face of Mt. King George are visible in the background, triggered by the Landslides from the 6 Dec 2025 Hubbard Glacier Earthquake.

Landslide activity was concentrated on the Mt King George massif, where rock–ice avalanches and rockfall were the most common failure types. Based on preliminary earthquake relocations, the King George massif directly overlies a portion of the fault rupture and rises to a height of 3,741 m, approximately 1,900 m above the surrounding Hubbard Glacier.

Landslide scars and debris on the NW end of the King George massif, looking toward Mt Logan (5,959 m). Note the lack of snow cover here due to concentrated avalanche and landslide activity, as compared to distant peaks.

Landslide activity continued for several days after the main earthquake, likely due to a combination of aftershocks and progressive failure of slopes that were damaged by the earthquake or destabilized by earlier landsliding. At least one rock avalanche occurred between 11 and 12 December as constrained by Landsat imagery.  At the time of the overview flight, slide scars on the east and northeast sides of Mt King George remained active, with ongoing rockslides and rockfall producing large dust clouds. The large slide scar on the east face of Mt King George appeared to have liquid water flowing down its centre, suggesting either discontinuous permafrost within the massif or significant heating associated with slope failure.

A large landslide scar on the east face of Mt King George appeared to have liquid water running out from approximately halfway down the scar (arrow). This scar was producing active rockfall at the time of the overview flight and filling adjacent valleys with dust.

The largest observed landslide was a rock and ice avalanche produced by a partial collapse of the southwest ridge of Mt King George. The basal failure surface occurred along a southwest-dipping planar discontinuity oriented subparallel with the pre-existing slope of the south flank of the ridge . The crown of the slide originated at approximately 3,000 m above sea level and descended roughly 1,300 m along a tributary glacier before coming to rest on the Hubbard Glacier, approximately 7.4 km from the source area. This corresponds to an overall travel angle of approximately 10 degrees. Such high mobility is typical of rock avalanches on glaciers (c.f.  Evans and Clague 1988), where movement is enhanced by the low-friction surface of the glacier, entrainment of snow and ice, and by water inputs generated through frictional melting (Sosio et al., 2012).

Source area and runout of the largest (9 square km) landslide triggered by the Mw=7.0 6 December 2025 Hubbard Glacier Earthquakeearthquake on the southwest ridge of Mt King George. The planar surface of failure for the largest rock and ice avalanche on the southern flank of the SW ridge of Mt King George.

Snow avalanches were common on all aspects and were triggered in a more extensive region than landslides. Some of the largest snow avalanches occurred on the north and east aspects of Mt King George and McArthur Peak (a sub-peak of Mt Logan) and produced plumes that in some cases extended 2-3 km across the glacier at the base of the slopes where they initiated. Damage to glaciers was also extensive; the collapse of snow bridges and seracs on icefalls was widespread on the Hubbard Glacier and adjacent tributaries. A partial collapse of a glacier occurred between Mt King George and Mt Queen Mary, an area immediately above many of the most intense aftershocks. This portion of glacier is covered by debris from a rock avalanche off the NE face on Mt King George which may have contributed to its failure. The most intensely affected area is in a popular recreation zone of Kluane National Park and may have significant impact on the objective hazards skiers and mountaineers face in the region over the coming years.

Partial collapse of a glacier between Mt King George and Mt Queen Mary. The length of the failure is approximately 2.4 km. Widespread collapse of seracs and snow bridges on the south side of Mt Queen Mary. The field of view mid-photo is approximately 5 km across. Widespread collapse of seracs and snow bridges on the south side of Mt Queen Mary. The field of view mid-photo is approximately 5 km across. Rock avalanche below Mt King George triggered by the 6 December 2025 Hubbard Glacier Earthquake. The runout distance is 1.4 km.

All photos provided courtesy of the Government of Yukon.

References:

Evans, S. G., & Clague, J. J. 1988. Catastrophic rock avalanches in glacial environments. In Proceedings of the Fifth International Symposium on Landslides, 2, pp. 1153–1158. Lausanne, Switzerland.

Sosio R., Crosta, G.B., Chen, J.H. and Hungr, O. 2012. Modelling rock avalanche propagation onto glaciers. Quaternary Science Reviews 47, 23–40

Return to The Landslide Blog homepage Text © 2026. The authors. CC BY-NC-ND 3.0
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The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.

Of course, allow me to start by wishing all my readers a Happy 2026. I suspect that we are in for quite a landslide journey again this year.

In late November, a very interesting open access paper (Darrow and Jacobs 2025) was published on the journal Landslides. This piece of work sought to understand the patterns of landslides in Alaska over a century through the creation of a database compiled from “a combination of 24 digital newspapers and online media sources, including historic digitised Alaskan newspapers”. Such a study is an epic amount of work, but yields fantastic data. This study is no exception.

What is of particular interest here is that Alaska suffers from a range of landslide hazards, and suffers significant losses from them, and it is an environment in which climate change is clearly occurring, with warming at a rate that is higher than the global average. Previous studies have shown that this is having a measurable impact on landslides in the mountains of Alaska.

In total, Darrow and Jacobs (2025) have identified 281 landslides since 1883 in Alaska, with the occurrence showing a strong seasonal pattern associated primarily with seasonal patterns of rainfall. The headline from the paper is summarised in this graphic from the paper:-

The recorded incidence of landslides in Alaska by decade, from Darrow and Jacobs (2025).

The data shows a dramatic increase in landslides in recent decades, and in particular in the last two decades or so. Of course, care is needed to ensure that this is not an artefact of the reporting of landslides, but Darrow and Jacobs (2025) explored this issue in detail, concluding that the signal is real. Fortunately, the number of fatalities caused by landslides in Alaska is small, and there is no significant trend in terms of fatal landslides.

So what lies behind this change? Darrow and Jacobs (2025) show that the increase in occurrence of landslides in Alaska is associated with a marked increase in in average annual air temperature that ranges between 1.2 C and 3.4 C, and an associated increase in precipitation that ranges from 3% to 27%, over the 50 years.

Of course, warming is not going to stop in Alaska in the next few decades, so the likely direction of travel in terms of landslides there is clear. There is recognition in Alaska that greater attention will be needed on landslides.

But more widely, this is further quantitative evidence that the climate is having a big impact on landslide hazard. It is remarkable how the evidence just keeps accumulating.

Reference

Darrow, M.M. and Jacobs, A. 2025. Read all about it! A review of more than a century of Alaskan landslides as recorded in periodicals. Landslides. https://doi.org/10.1007/s10346-025-02663-z.

Return to The Landslide Blog homepage Text © 2026. The authors. CC BY-NC-ND 3.0
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Source: AGU Advances

In 2023, Earth experienced its warmest year since 1850, with heat waves stretching across oceans and land alike. East Asia, for example, experienced scorching temperatures and high humidity throughout the summer months. Humid-heat extremes like those seen that year can trigger heat-related illnesses and mortality at higher-than-average rates.

As on land, the ocean around East Asia also experienced unprecedented warming in 2023. Sea surface temperatures (SST) in the Kuroshio-Oyashio Extension region reached record highs, persisting through much of the year. Researchers know that marine heat waves can influence land heat waves, but the details of these connections remain unclear.

Okajima et al. modeled regional land-sea interactions to better understand the effects of the unprecedented 2023 marine heat wave on conditions on land in East Asia. The team focused on the peak hot and humid months of July, August, and September, using hourly data on atmospheric conditions, including temperature, humidity, wind velocity, and atmospheric pressure, as well as SST data from satellites and in situ sensors.

The modeling suggested that the 2023 marine heat wave greatly exacerbated the East Asian heat wave, particularly in Japan, by affecting atmospheric circulation and altering the usual radiative effects of clouds and water vapor. The team said the influence of the marine heat wave explains roughly 20% to 50% of the increase in the intensity and duration of hot and humid conditions observed on land in East Asia in summer 2023.

The scientists note that this research provides valuable insights that could help improve long-range weather predictions. Such predictions may help communities prepare for health risks, particularly in Asia, which the World Meteorological Organization reported earlier this year is warming twice as fast as the global average. (AGU Advances, https://doi.org/10.1029/2025AV001673, 2025)

—Sarah Derouin (@sarahderouin.com), Science Writer

Citation: Derouin, S. (2025), Marine heat waves can exacerbate heat and humidity over land, Eos, 107, https://doi.org/10.1029/2026EO260009. Published on 2 January 2026. Text © 2026. 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.

What Corals Can Tell Us about Climate

Coral reefs are proxies for past climates, as well as archives for the future. Beneath their dazzling colors and displays are “rocklike skeletal structures containing annual bands, similar to tree rings.” And like tree rings, coral cores offer valuable insights “into past environmental conditions because coral growth can respond sensitively to climate variability.”

That accessible explanation comes from scientist-authors Avi Strange, Oliwia Jasnos, Lauren T. Toth, Nancy G. Prouty, and Thomas M. DeCarlo, as they introduce readers to CoralCT, an innovative repository of coral images taken with X-ray and computed tomography technology. The result is “A Coral Core Archive Designed for Transparency and Accessibility”—and a resource documenting years, centuries, and sometimes millennia of climate change and ecosystem adaptation.

The CoralCT archive contains images from around the world—the Great Barrier Reef, the Caribbean, the Red Sea. The scientists studying how “Coral Cores Pinpoint the Onset of Industrial Deforestation” have a more narrow focus: just three reefs in the South China Sea off Malaysian Borneo. The changing ocean chemistry preserved by these coral cores serves as a record of excess erosion, a known consequence of deforestation.

Rapidly rising sea levels, increasing ocean temperatures, and acidifying waters are threatening coral reefs and their contribution to the climate record. As the ocean becomes increasingly inhospitable, researchers are turning to both geoengineering and cryopreservation to save hundreds of coral species. Some researchers are exploring the prospects for stratospheric aerosol injection to help save corals from bleaching, while others have established a cooperative cryobank network for the Coral Triangle.

This month’s thematic collection shares how coral reefs are more than just pretty polyps. They are vital resources for scientists studying the history of Earth’s climate and documenting its present state.

—Caryl-Sue Micalizio, Editor in Chief

Citation: Micalizio, C.-S. (2026), Preserving corals to study the past and document the present, Eos, 107, https://doi.org/10.1029/2026EO260008. Published on 1 January 2026. Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

It’s been a trying year for science and scientists, and I’m proud of the way Eos is meeting the moment with a new blog, Research & Developments (R&D), dedicated to quickly relaying content and context for science news. Anchoring R&D coverage is our Science Policy Tracker, updated multiple times a day with late-breaking stories from around the world. Bookmark it!
—Caryl-Sue Micalizio, Editor in Chief

Crowds Stand Up for Science Across the United States. In March, Eos reporters and editors documented huge Stand Up for Science rallies across the country. The resulting story conveys the inspiring passion, anger, hope, and resilience of scientists who faced monumental challenges this year.
—Grace van Deelen, Staff Writer

I struggled to narrow down my favorite science stories of 2025, but there were two standouts. The first is an Eos article written by Katherine Bourzac about air pollution, environmental racism, and the difficulties that come with measuring and regulating odors. The second is a short documentary from The New York Times featuring unbelievably crisp audio of a melting glacier. I also enjoyed these two articles about health risks associated with access to air-conditioning and climate doulas.
—Anaise Aristide, Senior Production and Analytics Specialist

This year started out with two devastating fires that swept through the L.A. area, displacing thousands of people and causing millions of dollars in damage. The area is home to scientists of all disciplines, many of whom sprang into action to understand the impacts of the fires even as themselves and their families were affected. Eos spoke with these scientists about the fires’ impact on air, land, sea, and the people in a four-part series, highlighting the strength and resilience of the science community in the face of disaster.
—Kimberly M. S. Cartier, Senior Science Reporter

When Disaster Science Strikes Close to Home. Amid Eos’s team coverage of science done in the aftermath of the January 2025 Los Angeles fire, I was inspired by Kimberley Cartier’s coverage of the local scientists who jumped in to lend a hand with data collection. The work these researchers did must’ve had physical and emotional tolls—and understandably, it wasn’t always appreciated in the moment by residents who’d just lost their homes—but it was an important supplement to agency efforts to document the fires’ myriad effects on public and environmental health and to communicate those effects to local communities.
—Timothy Oleson, Senior Science Editor

Video Shows Pulsing and Curving Fault Behavior. This article wins 2025 for its sheer coolness. By pure chance, a security camera captured video of the Myanmar earthquake (which I may have replayed more than a dozen times). This visually confirmed the curvature of fault slip and that earthquakes propagate in pulses. The story includes a word that was new to me—always a plus: slickenline. The scientists’ analysis of the video showed that these scratch marks relate to the direction an earthquake traveled, with implications for future hazards if an earthquake tends to rupture in one direction.
—Faith Ishii, Assistant Director, Operations

33.8 Million People in the United States Live on Sinking Land. This article by our colleague Grace van Deelen was both fascinating and dismaying. I mean, most of us knew that New Orleans and Venice were sinking. But New York is sinking! Denver is sinking! Houston is sinking! Because much of this subsidence is linked to human activities like infrastructure building and groundwater pumping, Grace’s coverage is an important way to raise awareness of this issue and of what can be done about it.
—Emily Gardner, Associate Editor

A Major Miner Problem. A difficult conundrum faces part of the geophysics workforce. As the realities of climate change have led to scientists withdrawing from the mining industry, it turns out we need experts in this field more than ever if we are to find the critical minerals for renewable energy in a way that can meaningfully supplant our reliance on oil and gas.
—Heather Goss, Publisher and Senior Director of Strategic Communications and Marketing

Sunspot Drawings Illuminate 400 Years of Solar Activity. I found the project to combine centuries-old data with modern technology for the benefit of present-day researchers fascinating, and I loved that historians were given credit as “detectives” and “real heroes” who “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.”
—Tshawna Byerly, Copy Editor

Scientists Discover an Ancient Landscape – in Our Own Backyard. I loved learning about the identification of ancient grasslands and meadow in Virginia.
—Lexi Shultz, Vice President of Science Policy & Government Relations

An Upgraded Alvin Puts New Ocean Depths Within Reach. The mysteries and oddities of the deep ocean are a never-ending source of amazement to me. So I loved learning about how the upgraded capabilities of the long-serving and extraordinarily productive Alvin submersible now put roughly 99% of the seafloor within scientists’ reach.
—Timothy Oleson, Senior Science Editor

The Doomsday Glacier Is Getting Closer and Closer to Irreversible Collapse. Our collective attention continues to zero in on the Thwaites Glacier. A new feature story in Wired covers research in JGR Earth Surface on the 20-year evolution of fractures near the glacier’s “pinning point” keeping it anchored to the West Antarctic Ice Sheet. Eos has long covered research on this important climate signal, nicknamed the “Doomsday Glacier,” including the National Science Foundation’s decision earlier this year to decommission the Nathaniel B. Palmer, the United States’ only Antarctic research vessel–icebreaker.
—Heather Goss, Publisher and Senior Director of Strategic Communications and Marketing

What If Our Ancestors Didn’t Feel Anything Like We Do? This is a feature in The Atlantic about a field that blends history, psychology, and neuroscience to try to determine whether emotions—like anger or disgust or love—actually felt the same to our ancestors. It’s a fascinating idea that’s well worth the read.
—Grace van Deelen, Staff Writer

The Truth About Testosterone. The Science Writers Association of the Rocky Mountains launched its inaugural science writing awards this year. I enjoyed this piece by Stephanie Pappas for Scientific American, which received an honorable mention. Deep, scientific dives into the health trends hawked by TikTokers and podcasters are almost always important, and I found this account particularly engrossing.
—Emily Gardner, Associate Editor

Small Satellites, Big Futures. This feature by Eos senior science reporter Kim Cartier spotlights several programs in which high school and college students can gain hands-on experience designing, building, and launching cubesats. Full of great quotations and photos, this article about encouraging and building up the next generation was a bright spot in a year full of bad news about science funding and programs.
— Faith Ishii, Assistant Director, Operations

Awesome turnout in support of @ncar-ucar.bsky.social at #AGU25. Take a look at how many people use our products!

[image or embed]

— Sam Rabin (@samsrabin.bsky.social) December 18, 2025 at 2:35 PM

It was gratifying to see virtually the entire scientific community rally behind the National Center for Atmospheric Research, much of it documented in the #SaveNCAR tag. Sometimes it’s easy to forget we’re all in this together, but we are.
—Caryl-Sue Micalizio, Editor in Chief

Because it is fun, I am going to include The Batman Effect: “In the control condition, a female experimenter, appearing pregnant, boarded the train with an observer. In the experimental condition, an additional experimenter dressed as Batman entered from another door. Passengers were significantly more likely to offer their seat when Batman was present (67.21% vs. 37.66%, OR = 3.393, p < 0.001). Notably, 44% of those who offered their seat in the experimental condition reported not seeing Batman. These findings suggest that unexpected events can promote prosociality, even without conscious awareness, with implications for encouraging kindness in public settings.” Science!
—Liz Crocker, Director, Thriving Earth Exchange

Penguin poop!
—Joshua Weinberg, Vice President, Strategic Communications and Marketing

—AGU

Citation: AGU (2025), Our favorite science stories of 2025, Eos, 106, https://doi.org/10.1029/2025EO250487. Published on 31 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.

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.