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Publication date: 15 February 2026

Source: Earth and Planetary Science Letters, Volume 676

Author(s): Yiran Wang, Aron J. Meltzner, Michael E. Oskin, Jennifer Quye-Sawyer, Lin Thu Aung, Noelynna Ramos

Publication date: 15 February 2026

Source: Earth and Planetary Science Letters, Volume 676

Author(s): Neil C. Sturchio, Hao Yan, Alian Wang, W. Andrew Jackson, Huiming Bao, Chuck Y.C. Yan, Linnea J. Heraty, Yu Wei, Quincy H.K. Qu, Kevin S. Olsen

Australian researchers have discovered a hidden climate superpower of trees. Their bark harbors trillions of microbes that help scrub the air of greenhouse and toxic gases.

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

The Trump administration 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.

Much of the western U.S. has started in 2026 in the midst of a snow drought. That might sound surprising, given the record precipitation from atmospheric rivers hitting the region in recent weeks, but those storms were actually part of the problem.

Greenland, the largest island on Earth, possesses some of the richest stores of natural resources anywhere in the world.

When engineers and planners design roads, bridges and dams, they rely on hydrological models intended to protect infrastructure and communities from 50- and 100-year floods. But as climate change increases the frequency and severity of floods, existing models are becoming less and less reliable, new Cornell research finds.

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

The correlation between Arctic wildfires and abnormal snow cover under global warming is of growing concern. A comprehensive quantitative assessment by researchers at The Hong Kong Polytechnic University (PolyU) has shown that increasingly frequent seasonal wildland fires across the Arctic in recent years have delayed snow cover formation by at least five days and could lead to a future 18-day reduction of snow cover duration, with implications for global ecosystems.

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

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. There can be up to about 5 times that much Sargassum in a 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.

SummaryTime-domain induced polarization (TDIP) data carry spectral information that can be used for petrophysical interpretation. At the same time, TDIP data can be collected in the field more efficiently than frequency-domain induced polarization (FDIP) data, thanks to the use of square-wave signals. However, TDIP field data are prone to noise, particularly strong near industrial installations and urban areas, above conductive media and in cases where little current is injected. The integral chargeability is a useful parameter to smoothen out the signal but it precludes any spectral interpretation. Debye decomposition (DD) is recognized as one of the best methods for spectral interpretation but the extracted parameters are particularly affected by data noise. More generally, processing TDIP data before further analysis, such as inversion or spectral analysis, is usually necessary for any quantitative interpretation. We propose here an automatic processing algorithm, based on the Kohlrausch-Williams-Watts (KWW) function, which is very close to the Havriliak-Negami model in frequency-domain, that fulfills this need. The processing is completed by an empirical handling of early-time electromagnetic coupling effects to improve the overall performance. The resulting procedure, tested and validated on three datasets that cover a large range of contexts, electrode configurations and acquisition settings, is available as open-source MATLAB scripts. The proposed approach is especially useful for further extracting spectral information from TDIP data through DD. Thanks to the theoretical framework offered by the KWW function, the behavior of the integral chargeability could be investigated in a systematic manner, using both synthetic and field TDIP data. Recommendations could be formulated on how to make use of the spectral information, while keeping the automatic processing transparent and accessible to unexperienced users. This work advances the use of TDIP in the field of environmental geophysics.

SummaryJoint petrophysical inversion is a powerful technique for using multiple geophysical modalities to estimate petrophysical or geotechnical parameters of the subsurface. A precise knowledge of the petrophysical laws for the full model domain is imperative to enable petrophysical coupling. In this work, we investigate the effect of partially invalid petrophysical laws on the inversion of a synthetic data set, using electrical resistivity tomography (ERT) and seismic traveltime data to image a CO2 plume in a Carbon Capture and Storage (CCS) setup. We consider a model consisting of a reservoir and a caprock in which only the reservoir can be described by a petrophysical law. We first apply a conventional (joint) petrophysical inversion (JPI) and show that the use of wrong petrophysical laws leads to systemic artefacts within the parts of the model in which the petrophysical relations are invalid. We then present a new hybrid partially petrophysically coupled joint inversion (P-JPI) approach that combines petrophysical coupling for regions with valid petrophysical laws, and structural coupling, whenever no reliable petrophysical laws are available. The P-JPI approach outperforms tomography based on the individual ERT or seismic data set, as well as joint structural inversion (JSI) based on the cross-gradient functional. The partially petrophysically coupled joint inversion thus enables petrophysical coupling and provides a unique, quantitatively interpretable saturation model for the CO2-plume. We further show that it is possible to detect zones with incorrect petrophysical relations by analysing the difference of the model updates based on the stand-alone data sets. Finally, we combine the detection of zones of incorrect petrophysical laws with the P-JPI to derive an inversion scheme that is independent of prior knowledge of the validity of petrophysical laws. Our novel methods facilitate direct estimation of the petrophysical subsurface parameters from multiple geophysical measurements if petrophysical relations are only available for parts of the model domain and provide means to quantify the spatial extent of regions where the petrophysical relations are valid.

SummaryThe rapid and accurate estimation of strong ground motion is essential for seismic hazard assessment and near-real-time disaster response. Although empirical ground motion models enable fast intensity predictions, they simplify the underlying physics and exhibit large uncertainties. Conversely, physics-based simulations — while capable of more accurately predicting ground shaking — are computationally expensive, making them impractical for large-scale hazard assessments and real-time event response. To overcome these limitations, we introduce a novel two-step machine learning framework that predicts peak ground velocity (PGV) for arbitrary double-couple sources positioned anywhere within a given medium, combining the accuracy of physics-based models with near-instantaneous inference. In the first step, an ensemble of XGBoost predictors, trained on a reciprocal Green’s function database, generates a sparsely sampled PGV map for any input source. In the second step, we refine this map into a continuous spatial prediction. By leveraging Green’s function reciprocity, our approach reduces the required number of simulations in training, lowering both computational cost and storage demands. Our framework provides spatially continuous PGV predictions and inherently accounts for complex 3D geological and topographic effects. It can deliver results within seconds while maintaining accuracy up to the highest frequency captured in the physics-based simulations. This makes PGVnet ideal for applications such as rapid earthquake disaster response, as well as large-scale probabilistic seismic hazard analyses and multi-hazard digital ecosystems. Validated in the geologically complex San Francisco Bay Area, our approach generates PGV maps consistent with physics-based simulations, offering an effective balance between computational speed and accuracy.

How do avalanches affect pylons and other sensitive infrastructure? Using detailed simulations, SLF researcher Michael Kohler has shown that the compressibility of snow initially reduces avalanche pressure, but that at high speeds this buffer suddenly fails.

Globally, toxic algal blooms are becoming more frequent and severe, fueled by a warming climate and nutrient runoff. While satellites can easily spot the green carpets once they reach the surface, the "prequels" to these outbreaks remain hidden in the deep.

Oxygen isotopes data enable researchers to look far back into the geologic past and reconstruct the climate of the past. In doing so, they consider several factors such as ocean temperature and ice volume in polar regions. A new publication by an international team from Bergen (Norway) and Bremen in Nature Geoscience concludes that the Antarctic ice sheet was less dynamic during the Oligocene epoch 34 to 23 million years ago than previously assumed.

NASA astronaut Nichole Ayers captured this image of lightning while orbiting aboard the International Space Station more than 250 miles above Milan, Italy on July 1, 2025.

The extent and speed of ice moving off the ice sheets of Greenland and Antarctica into the sea—an important dynamic for climate and sea-rise modeling—has been captured over a 10-year period by satellites from the Copernicus Sentinel-1 mission.