EOS

The textbook explanation of how hailstones grow goes something like this: Nuclei collect frozen layers as they are repeatedly lofted up and fall through clouds. But scientists have had hints that this up-down cycle doesn’t always reflect real hailstones’ journeys. Now researchers have revived an old technique to track dozens of hailstones. The new results suggest that many hailstones take simpler paths.

The idea that hailstones grow as they repeatedly rise and fall on repeat arose as a way to explain stones’ alternating layers of different transparencies, said Xiangyu Lin, an atmospheric scientist at Peking University in Beijing and an author on the new study. But scientists don’t have any direct observations of individual hailstones’ paths in clouds because the severe storms that produce hail are difficult, even dangerous, to observe.

“The vast majority of our understanding of how hail grows has come from numerical modeling,” said Matthew Kumjian, an atmospheric scientist at Pennsylvania State University who wasn’t part of the study. The new research is “a nice piece of experimental evidence” to validate those models, he said.

“Over the past 8 years, we have collected more than 3,000 hailstones.”

At a seminar at Peking University in 2018, Kumjian showed a simple arcing trajectory—rather than a yo-yoing one—for simulated hailstones. Seeing those results, one of Lin’s colleagues at Peking University, atmospheric scientist Qinghong Zhang, wondered whether she could find real hailstones that followed a similar path. That year she started collecting hailstones, using social media to ask the public to save the icy orbs. “Over the past 8 years, we have collected more than 3,000 hailstones,” she said.

To trace the hailstones’ trajectories, the team turned to stable isotopes. At lower altitude, the ice that forms on hailstones tends to have a greater concentration of heavier isotopes of hydrogen and oxygen than the ice that forms higher up. Researchers can measure the ratio of heavy and light isotopes in a layer, providing a postmark of sorts for the altitude at which the ice originated.

The scientists analyzed 27 hailstones from nine different storms spread across eastern China. They sliced each stone in half to reveal its layers. Then they cut the hailstones down layer by layer, so they could melt each layer and measure its isotopes. To find the link between isotope concentrations and height in a storm cloud, the team used temperature, humidity, and pressure data from weather balloons that floated through the atmosphere near each storm.

Hailing from Where?

The isotopes showed that of the hailstones they analyzed, only one had more than one upward flight segment. A few hailstones grew at a relatively constant altitude, and 16 either rose or fell steadily as they grew.

Eight hailstones ascended once before falling to the ground. These eight hailstones were significantly larger than the other stones, Lin said. Hailstones primarily grew between −10°C and −30°C, the team found. With their up-and-down path, these eight stones seem to have spent more time in that zone, causing them to grow larger than others.

Many hailstones are not perfect spheres. Credit: Xiangyu Lin

Scientists used stable isotope analysis on hailstones some 50 years ago, but the technique fell out of favor, Kumjian said. Many of those early studies analyzed a small number of stones from few storms or sometimes a single storm. The new study is “bringing back this old type of analysis with modern methods,” he said.

But the analysis required assumptions that might cloud results. For instance, updrafts can mix air from different altitudes, Kumjian said. That can affect the isotopes in a hailstone’s layers.

Scientists are still exploring questions about hail across a range of scales from stone to storm. Though researchers know what sorts of storms can produce damaging hail, it’s hard to predict which will rain down baseball-sized stones or where exactly hail will fall. Meanwhile, the physics of hailstones’ growth is tricky. Researchers typically model stones as perfect spheres—a far cry from the bumpy lumps that fall from the sky. But those shapes affect how fast hail falls and the damage it can produce, Kumjian said.

“It’s a very exciting time in the hail world. We’re going to learn a lot in the coming years.”

Researchers are using modeling, radar observations, and isotope studies such as this one to improve forecasts. Hail can knock out crops, damage structures, and shatter solar panels. Even 10 minutes of warning is enough for people to move cars and prevent damage, Zhang said.

Kumjian is part of a team that is launching instrumented Styrofoam spheres into clouds that could provide insights on actual paths taken by stones. Zhang’s team is continuing to study isotopes in layers, now looking at larger stones that formed in storms over Italy. “It’s a very exciting time in the hail world,” Kumjian said. “We’re going to learn a lot in the coming years.”

—Carolyn Wilke (@CarolynMWilke), Science Writer

Citation: Wilke, C. (2025), Isotopes map hailstones’ paths through clouds, Eos, 106, https://doi.org/10.1029/2025EO250206. Published on 30 May 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.

Sixty-seven extreme heat events have occurred since May 2024. All of these events—including a deadly Mediterranean heat wave in July 2024, an unprecedented March 2025 heat wave in central Asia, and extreme heat in South Sudan in February 2025—broke temperature records, caused major harm to people or property, or did both.

According to a new analysis, each of these extreme events was made more likely by climate change. The number of days with extreme heat is now at least double what it would have been without climate change in 195 countries and territories. Climate change added at least an extra month of extreme heat in the past year for 4 billion people—half the world’s population. 

“The numbers are staggering.”

“There’s really no corner of the globe that has been untouched by climate-driven extreme heat,” said Kristina Dahl, a climate researcher at the climate change research and communication nonprofit Climate Central who was part of the report team. “Half the world’s population is experiencing an extra month of extreme heat. The numbers are staggering.”

The authors of the report say it serves as a stark reminder of the dangers of climate change and the urgent need for better early-warning systems, heat action plans, and long-term planning for heat events across the globe. 

The report was created by scientists at Climate Central; World Weather Attribution, a climate research group; and the Red Cross Climate Centre. 

More Frequent Heat

In the new report, scientists calculated the number of days between 1 May 2024 and 1 May 2025 in which temperatures in a country or territory were above 90% of the historical temperatures from 1991 to 2020. Then, they analyzed how many of these extreme heat days were made more likely by climate change using the climate shift index, a methodology developed by Climate Central that compares actual temperatures to a simulated world without human-caused climate change. 

The team found that climate change made extreme heat events more likely in every country.

Over all the countries and territories, climate change added the greatest number of extreme heat days to the Federated States of Micronesia (57 days), and Aruba had the most extreme heat days in total over the past year, 187 days. The report’s authors estimate that in a world without climate change, Aruba would have experienced just 45 days of extreme heat.

Other Caribbean and Oceanic islands were among the countries and territories most strongly affected by climate change. People in the United States experienced 46 days of extreme heat, 24 of which were added by climate change. 

The authors of the report calculated the number of extreme heat days added by climate change in the past year. Credit: World Weather Attribution, Climate Central, and Red Cross Red Crescent Climate Centre

Of the 67 extreme heat events that occurred in the past year, the one most influenced by climate change was a heat wave that struck Pacific islands in May 2024. Researchers estimated the event was made at least 69 times more likely by climate change. 

The findings are not a surprise to Nick Leach, a climate scientist at the University of Oxford who was not involved in the report. “We’ve understood the impact of climate change on temperature and extreme heat for quite some time…[including] how it’s increasing the frequency and intensity of extreme heat,” he said. Research has consistently shown that heat events on Earth are made more likely, more intense, and longer lasting as a result of climate change. 

“Only comprehensive mitigation, through phasing out fossil fuels, will limit the severity of future heat-related harms.”

Leach said the new report gives a good overview of how climate change is influencing heat waves worldwide. However, defining extreme heat as temperatures above the 1991–2020 90th percentile creates a relatively broad analysis, he said. Studies using a more extreme definition of extreme heat may be more relevant to the impacts of extreme heat, and studies estimating those impacts are typically more policy relevant, he said.

The report’s authors chose the 90% threshold because heat-related illness and mortality begin to increase at those temperatures, Dahl said. 

Taking Action on Heat Waves

For rising global temperatures, “the causes are well known,” the report’s authors wrote. Burning of fossil fuels such as coal, oil, and gas has released enough greenhouse gases to warm the planet by 1.3°C (2.34°F; calculated as a 5-year average); 2024 marked the first year with average global temperatures exceeding 1.5°C (2.7°F) above preindustrial temperatures.

“Only comprehensive mitigation, through phasing out fossil fuels, will limit the severity of future heat-related harms,” the authors wrote.

Extreme heat puts strain on the human body as it tries to cool itself. This strain can worsen chronic conditions such as cardiovascular problems, mental health problems, and diabetes and can cause heat exhaustion and heat stroke, which can be deadly. Extreme heat is particularly dangerous for already-vulnerable populations, including those with preexisting health conditions, low-income populations lacking access to cool shelter, and outdoor workers. 

Heat Action Day on 2 June, hosted by the International Federation of Red Cross and Red Crescent Societies, raises awareness of heat risks across the globe. This year, the day of action will focus on how to recognize signs of heat exhaustion and heat stroke. Dahl recommends using the Centers for Disease Control and Prevention tips on heat and health to stay safe. “Most heat-related illness and death is preventable,” she said.

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

Citation: van Deelen, G. (2025), Climate change made extreme heat days more likely, Eos, 106, https://doi.org/10.1029/2025EO250208. Published on 30 May 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

The relationship between phytoplankton production and dissolved iron affects the net annual air-sea exchange of carbon dioxide and impacts the ability of the subantarctic Southern Ocean to act as a carbon sink.

Traill et al. [2025] combine 27 years of monitoring data from a time series site in the subantarctic Southern Ocean south of Australia with ship-based observations to develop a composite seasonal cycle of productivity and dissolved iron. The seasonal cycle shows three phases that are defined by controls on production by light and multiple iron sources (Phase 1), iron limitation (Phase 2), and biomass decline from a shift to net heterotrophy and recycled nutrients (Phase 3). The seasonal cycle of coupling between dissolved iron and productivity provides validation of ocean biogeochemical models and informs understanding of variability associated with changing Southern Ocean iron supply mechanisms. 

Citation: Traill, C. D., Rohr, T., Shadwick, E., Schallenberg, C., Ellwood, M., & Bowie, A. (2025). Coupling between the subantarctic seasonal iron cycle and productivity at the Southern Ocean Time Series (SOTS). AGU Advances, 6, e2024AV001599.  https://doi.org/10.1029/2024AV001599

—Eileen Hofmann, Editor, AGU Advances  

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

On 27 May, the United States Supreme Court declined to hear arguments from a group of Apache leaders challenging a copper mine that would damage land that tribe members consider sacred, according to the Los Angeles Times. 

The mine is planned to be built beneath Oak Flat, a 4,600-acre area in southeastern Arizona. The site sits within the state’s “Copper Triangle,” an area home to one of the largest clusters of copper deposits in the world. Magma intrusions and subsequent subsurface movement of high-pressure, metal-rich fluids about 65 million years ago created high-grade copper deposits.

According to mining company Resolution Copper, a joint venture of two other mining companies, Rio Tinto and BHP, the deposit at Oak Flat is particularly high grade, at 1.5% copper, making the site attractive for industrial activity.

Members of Apache Stronghold, a tribal advocacy group, traveled on a two month pilgrimage last year to Washington, D.C., to present an appeal to the Supreme Court, asking them to review a decision on their case, Apache Stronghold v. United States of America, by the 9th U.S. Circuit Court of Appeals that had ruled narrowly in favor of moving the mine project forward.

In the case, Apache Stronghold argued that the development of the copper mine would violate the First Amendment rights of Indigenous community members who consider Oak Flat an important religious site. 

 
Related

•  Here’s Why Resolution Copper Wants to Mine Oak Flat
•  Supreme Court Clears Way for Massive Copper Mine on Apache Sacred Land
•  Supreme Court Refuses to Hear Oak Flat Case, Clearing a Roadblock for Huge Copper Mine
•  Get Involved: AGU Science Policy Action Center
 

The Supreme Court’s decision not to hear arguments from Apache Stronghold means the U.S. Forest Service is now allowed to move forward with plans to create a final environmental impact report and solicit a final round of public comments before deciding whether to transfer the land to Resolution Copper. 

Justices Neil Gorsuch and Clarence Thomas dissented from the denial of the appeal. Gorsuch wrote that the decision not to hear the arguments was a “grievous mistake—one with consequences that threaten to reverberate for generations.”

“Faced with the government’s plan to destroy an ancient site of tribal worship, we owe the Apaches no less,” Gorsuch wrote. “They may live far from Washington, D.C., and their history and religious practices may be unfamiliar to many. But that should make no difference.”

“We are pleased that the Ninth Circuit’s decision will stand,” said Vicky Peacey, Resolution Copper’s general manager, in a statement. “The Resolution Copper mine is vital to securing America’s energy future, infrastructure needs, and national defense.”

“We will never stop fighting—nothing will deter us from protecting Oak Flat from destruction,” said Wendsler Nosie Sr., leader of Apache Stronghold, in a statement.

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

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2025. AGU. CC BY-NC-ND 3.0
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Source: Journal of Geophysical Research: Oceans

The Atlantic Meridional Overturning Circulation (AMOC) serves as the Atlantic Ocean’s conveyor belt, transporting warm water north toward the Arctic Circle and returning cold, dense water back to the tropics. Nearshore areas off Greenland are critical sites in AMOC, influencing the redistribution of heat and nutrients around the world.

The continental shelf along Greenland’s coast is marked by deep grooves called glacial troughs that extend from the mouths of glacially carved fjords to the open ocean. Research in Antarctica suggests glacial troughs there enhance the mixing of cold and warm waters, but few observations have been collected to determine whether the same is true of Greenland’s troughs.

Aboard R/V Neil Armstrong in late summer 2022, as part of an Overturning in the Subpolar North Atlantic Program cruise funded by the National Science Foundation, Nelson et al. explored how troughs influence ocean circulation around Greenland. They collected data in southwestern Greenland at the Narsaq Trough, which is 30 kilometers wide at its mouth and reaches 600 meters at its deepest point—about 4 times deeper than the average surrounding continental shelf. Gathering measurements along multiple ship tracks allowed the researchers to compare water mass properties in and outside the trough, describe flows in and around it, and estimate the mixing of waters with different temperatures and nutrient concentrations.

The results showed that the Narsaq Trough provides a pathway for warm, salty Atlantic Water to intrude onto the continental shelf and mix with cold, fresh polar waters. Consequently, waters in the trough are fresher, richer in oxygen, less rich in nutrients, and sometimes colder than nearby offshore waters. These changes in water conditions may slightly limit melting of glacial ice in the adjacent fjord. Furthermore, the trough creates subsurface circulation that likely exports the modified water from the trough, which may increase stratification and decrease deepwater formation off the continental shelf.

The study offers new insights into Greenland’s understudied glacial troughs and their role in modulating the climate system, the authors say. They note, however, that more work is needed to establish the troughs’ cumulative effects on global ocean circulation. (Journal of Geophysical Research: Oceans, https://doi.org/10.1029/2024JC022246, 2025)

—Aaron Sidder, Science Writer

Citation: Sidder, A. (2025), How Greenland’s glacial troughs influence ocean circulation, Eos, 106, https://doi.org/10.1029/2025EO250205. Published on 29 May 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.

“Everyone benefits from more accurate [orbital tracking] of the asteroids, from missions that are going there to observers on the ground that want to look at them from various telescopes.”

Data from the spacecraft that created the most accurate map of the Milky Way are being used to study objects in our own solar system. Information provided by the European Space Agency’s Gaia satellite have now enabled astronomers to measure the masses of hundreds of asteroids, allowing for improved orbital calculations.

“Everyone benefits from more accurate [orbital tracking] of the asteroids, from missions that are going there to observers on the ground that want to look at them from various telescopes,” said Oscar Fuentes-Muñoz, a NASA postdoctoral fellow at the Jet Propulsion Laboratory in California. Fuentes-Muñoz presented the masses of 231 asteroids he and his colleagues determined using Gaia last month at the Lunar and Planetary Sciences Conference in Houston.

The new research more than doubles the number of known asteroid masses, and the results are only the beginning.

“This work…is really pushing for high precision with novel techniques,” said Kevin Walsh, a solar system dynamicist who studies asteroids at the Southwest Research Institute in Colorado. Walsh was not part of the study.

Gravity Assist Asteroids

The new research relied on a familiar staple of Newtonian physics, taught in high schools everywhere: When two objects interact, each mass exerts a gravitational force on the other. The result is often negligible—the gravitational force of your phone isn’t going to pull you across the room.

But if the objects are moving and the mass difference is large enough, the more massive object will change, or perturb, the path of the less massive one. Fuentes-Muñoz called the phenomenon a “gravitational assist” and compared the relationship between massive and less massive asteroids to the way Earth’s mass perturbs the orbit of a satellite. “The mass of the satellite doesn’t affect the motion of the Earth,” he explained, but the path of the satellite can be dramatically altered.

Although they were not part of its primary mission, the star mapper Gaia was developed with solar system observations in mind and was able to tease out such interactions in incredible detail before being decommissioned in March. According to Gaia team member Mikael Granvik of the University of Helsinki, the telescope’s precision was comparable to observing a 2-euro coin on the Moon while standing on Earth.

As asteroids interacted, Gaia captured how their orbits shifted over 66 months. Fuentes-Muñoz and his colleagues used that information to determine the gravitational mass of the larger objects. Gravitational mass is a way to measure an object’s mass on the basis of how it moves in gravity, rather than calculating the object’s absolute mass in kilograms, for example. This type of measurement is commonly used to estimate the masses of solar system bodies as well as Earth-orbiting satellites and spacecraft.

Most of the 1.4 million known asteroids are too small to have their masses measured, however. “We can estimate things that are maybe…a thousand times smaller than Ceres, but not a million times,” Fuentes-Muñoz said.

Of the more than 1,000 large asteroids they observed, the researchers were able to more precisely calculate the gravitational masses of nearly 300 previously discovered objects. This calculation significantly increases the precision of asteroid orbits.

The dwarf planet Ceres is the largest object in the asteroid belt, and Fuentes-Muñoz calculated its gravitational mass, providing “ground truth” to previous measurements. The new research puts Ceres’s gravitational mass at 62.650 cubic kilometers per square second, which closely matches previous estimates and demonstrates the accuracy of the researchers’ technique. (For comparison, Earth’s gravitational mass is 398,600 cubic kilometers per square second.)

Gaia Is the Gift That Keeps Giving

Gaia wrapped up its mission after more than a decade in space, but new results continue to pour in. That’s due in part to the strict scrutiny the Gaia team uses before releasing data publicly.

Fuentes-Muñoz used the focus product release (FPR), sort of a halfway step between Gaia’s data release (DR) 3, released in 2022, and DR4. DR4 will be released no sooner than this summer, and DR5 won’t be released before the end of 2030.

“It was interesting to see that they got so many accurate masses already from just the FPR,” said Granvik, who reported the first observations of asteroid mass using Gaia in 2022.

“It’s a significant change overall. We’re going to get hundreds of asteroid masses.”

Granvik said Gaia will eventually provide “up to a tenfold increase in the sheer number of objects that we have masses” for.

Walsh said increased precision “will just really help nail down masses and the perturbative effects down to smaller and smaller asteroids.”

“It’s a significant change overall,” Fuentes-Muñoz said. “We’re going to get hundreds of asteroid masses.”

—Nola Taylor Tillman (@astrowriter.bsky.social), Science Writer

Citation: Tillman, N. T. (2025), The late, great Gaia helps reveal asteroid masses, Eos, 106, https://doi.org/10.1029/2025EO250204. Published on 29 May 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

Healthy soils are vital for sustaining life on Earth. They are essential for ecosystems, agricultural production, and clean water, and even help to regulate climate.

A new article in Reviews of Geophysics explores the latest scientific methods for monitoring soil health, including innovative tools like digital twins and satellite-enabled programs, while highlighting persistent gaps in linking indicators to soil functions across scales. Here, we asked the authors to give an overview of the topic.

What is soil health, and how is it different from soil quality?

A healthy soil is a thriving ecosystem: it feeds plants, filters water, stores carbon, and supports worms, microbes, and other tiny lifeforms.

Think of soil health as the soil’s ability to “stay alive” and do its job. A healthy soil is a thriving ecosystem: it feeds plants, filters water, stores carbon, and supports worms, microbes, and other tiny lifeforms. Soil quality, on the other hand, usually refers to how good soil is for growing crops. Soil health is the bigger picture—it’s about keeping soil thriving not just for farms, but for nature and our planet.

Why does soil health matter?

Healthy soil is a multifunctional linchpin of terrestrial ecosystems. It secures food production by nurturing crops, acts as a natural water filter by retaining pollutants, and serves as a massive carbon sink, sequestering atmospheric CO₂ to mitigate climate change—a process monitored at continental scale through EU’s initiatives such as LUCAS, which tracks soil carbon through satellite and field data. Simultaneously, it harbors diverse subterranean communities, from bacteria to earthworms, that drive nutrient cycling and enhance ecosystem resilience against droughts, floods, and pathogens.

How do we measure soil health?

Scientists assess three core dimensions:

1. Physical properties: Structure (e.g., root penetration, water retention).
2. Chemical properties: Nutrient availability and pH balance.
3. Biological properties: Microbial and macrofaunal activity (e.g., decomposition rates).

Emerging tools, such as satellite spectral imaging and AI-driven digital twins, integrate landscape-scale data (e.g., erosion patterns, vegetation cover) to contextualize field measurements. However, challenges persist in scaling microscale processes (e.g., nutrient cycling) to predict landscape-level outcomes.

Why are soil microbes so important?

Soil microbial communities (bacteria, fungi, archaea) are indispensable biogeochemical agents. They decompose organic matter, recycle nutrients, and secrete substances that stabilize soil aggregates, reducing erosion. Microbial communities also suppress plant pathogens and form symbiotic relationships with roots, enhancing crop resilience. Their absence leads to soil degradation, compromising biophysical integrity and triggering cascading declines in ecosystem functionality.

How does water affect soil health?

Water is the lifeblood of soil ecosystems.

Water is the lifeblood of soil ecosystems. Optimal moisture sustains plant hydration and microbial activity. Excess water, however, induces hypoxia, impairing root respiration and promoting anaerobic processes like methanogenesis. Prolonged drought destabilizes soil structure, increasing erosion risks. Healthy soils counteract these extremes through stable aggregates and organic matter, acting like sponges to store water during droughts and absorb rainfall during floods.

Can satellites truly monitor soil health?

Yes. Programs like the EU’s LUCAS integrate satellite data (e.g., Copernicus Sentinel-2’s multispectral imaging for organic carbon) with ground surveys—more than 100,000 soil samples collected between 2009 and 2022 for physical, chemical, and biological analysis. This hybrid approach identifies degraded zones, evaluates restoration efforts, and scales localized data (e.g., nutrient cycles) to landscape processes. These datasets also feed into digital twins, enabling predictive models that inform policies like the EU Soil Monitoring Law.

What’s a “digital twin” for the soil-plant system?

A digital twin is a dynamic, computer-based replica of a physical system – in this case, the soil-plant-environment continuum. It simulates critical processes like water, nutrient, and energy flows (e.g., using models like STEMMUS-SCOPE) and continuously improves its accuracy by assimilating real-time sensor data. This creates a virtual laboratory where we can test responses to challenges like drought or pollution without risking real ecosystems. While the concept originated in aerospace, digital twins now drive major initiatives like the EU’s Destination Earth for modeling climate extremes. Leveraging recent advances in AI and satellite data, we can now perform continent-scale soil health monitoring and scenario modeling, optimizing and transforming land management practices.

What critical gaps remain in our understanding of soil health?

Safeguarding soil health is not just an ecological imperative but a cornerstone of humanity’s future.

Key unknowns include feedback loops between soil structure and microbial communities, scaling microscale processes (e.g., nutrient cycling) to landscapes, and predicting climate impacts on soil carbon and microbial symbioses. Practical hurdles include fragmented global datasets, limited integration of microbial traits in models, and cost-effective tools for farmers. Collaborative platforms like the EU Soil Observatory bridge research and policy, but challenges like modeling root-water-nutrient dynamics in heterogeneous soils or fusing satellite-ground data persist. Addressing these gaps requires interdisciplinary innovation—an urgent task, as safeguarding soil health is not just an ecological imperative but a cornerstone of humanity’s future.

—Yijian Zeng (y.zeng@utwente.nl, 0000-0002-2166-5314), University of Twente, Enschede, The Netherlands; and Bob Su (0000-0003-2096-1733), University of Twente, Enschede, The Netherlands

Editor’s Note: It is the policy of AGU Publications to invite the authors of articles published in Reviews of Geophysics to write a summary for Eos Editors’ Vox.

Citation: Zeng, Y., and B. Su (2025), Keeping soil healthy: why it matters and how science can help, Eos, 106, https://doi.org/10.1029/2025EO255016. Published on 29 May 2025. This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

Over the course of the last few days, I have been blogging about the evolving situation on the slopes above Blatten in Switzerland. I documented that attention slowly transitioned from worries about the stability of the slope on Kleine Nesthorn (Petit Nesthorn in French) to concerns about the stability of the Birch Glacier due to increased loading from the rockslide debris. Yesterday, I outlined three scenarios and emphasised that we were in unknown territory.

On 28 May 2025, the Birch Glacier catastrophically collapsed, generating the massive landslide that had been the source of concern. The move by the authorities to evacuate the village proved to be the correct call, but tragically a 64 year old resident appears to have been buried in the landslide. Assuming that he was indeed in the area, their prospects are bleak.

Others have covered the failure event better that can I, and once again I recommend two Bluesky accounts that have provided amazing insights. First, there is Melaine Le Roy, who has posted this for example:-

Seeing Blatten buried again and again, from every angle…Properly staggering!

Pine Hollow Arboretum’s founder, John W. Abbuhl, began planting trees around his Albany, N.Y., home in the 1960s. He planted species native to surrounding ecosystems but also made ambitious choices—bald cypresses, magnolias, pawpaws, sweetgums—that were more climatically suited to the southeastern United States.

Now, those very trees are thriving, said Dave Plummer, a horticulturalist at Pine Hollow. 

Other Pine Hollow trees, such as balsam firs native to New York, have struggled with this century’s warming winters. “We’re noticing they’re not doing as well as they were maybe 5 to 10 years ago,” Plummer said. “These are trees that are just meant to be in more northern climates where the winters are harsher, and we just don’t have those winters [anymore].”

Pine Hollow Arboretum is one of many botanical gardens rethinking their planting strategies as the climate warms. These strategies range from testing out new, warmth-loving plants to putting more resources toward pest and invasive species management. 

Planting Zones Shift North

The U.S. Department of Agriculture recognizes 13 plant hardiness zones based on a region’s coldest annual temperatures, averaged over a period of 30 years. These zones guide gardeners’ planting decisions by advising which species of plants, especially perennials, are most likely to thrive in a specific zone.

A new report from Climate Central, a climate change research and communication nonprofit, lays out stark changes to these zones.

Scientists compared 30-year coldest temperature averages from the past (1951–1980) and present (1995–2024) at 247 locations across the United States using NOAA’s Applied Climate Information System dataset. They found that 67% of locations have shifted to warmer zones since the 1951–1980 period.

“The effects of a changing climate on plants and plant communities will be significant and, unfortunately, without precedent.”

They also used the most recently released phase of the Coupled Model Intercomparison Project (CMIP) to simulate how planting zones might shift by mid-century. In the CMIP6 scenario they used, carbon emissions decline but do not stay under Paris Agreement limits, a framework consistent with the Shared Socioeconomic Pathway 2-4.5 “middle of the road” scenario.

The models predict that the mid-century average annual coldest temperatures during the 2036–2065 time period will warm in 100% of the country by an average of 3.1°C (5.6°F). Coldest annual temperatures in the Upper Midwest, Alaska, the Northern Rockies and Plains, and the Northeast and Ohio Valley were projected to warm the most. 

Plant hardiness zones have shifted northward in much of the United States. Credit: Climate Central Longer Seasons, Looming Threats

The results match what staff at Pine Hollow and Mount Auburn Cemetery in Cambridge, Mass., have seen. At the cemetery (which is also a botanical garden), staff have begun to test whether plants that traditionally couldn’t survive cold Massachusetts winters can now thrive. For example, staff there have begun testing crepe myrtles and paperbush, two flowering shrubs that have survived recent winters.

Staff at the Mount Auburn Cemetery in Cambridge, Mass., have tested various plants’ tolerances for warming winters, including this crepe myrtle. Credit: Mount Auburn Cemetery/Jessica Bussman

In Minnesota, plant hardiness zones have shifted by about half a zone since 1951–1980.

Laura Irish-Hanson, an educator and horticulturist at the University of Minnesota, tells students and local gardeners to pay attention to the hardiness map when shopping for perennials and to consider planting species more adapted to warmer climates. “Don’t just look at things that, 200-300 years ago, were native to Minnesota,” she said. “Try things that, historically, maybe are native to Iowa, or Illinois, or parts of Wisconsin that are warmer.”

Mount Auburn is also taking the long view. “The effects of a changing climate on plants and plant communities will be significant and, unfortunately, without precedent,” said Ronnit Bendavid-Val, vice president of horticulture and landscape at Mount Auburn Cemetery, in an email. “We can make informed guesses about a certain plant’s resiliency and toughness based on what is known about its adaptability to extremes in the habitats where its species evolved over millennia. However, horticulturally speaking, ‘plant hardiness’ and fitness can be a vexing subject.”

Anchorage, Alaska, is among the cities that have experienced the largest increase in average annual coldest temperatures, according to the Climate Central report, jumping from −29.8°C (−21.6°F) during 1951–1980 to −24.8°C (−12.6°F) during 1995–2024. 

At the Alaska Botanical Garden in Anchorage, hardiness zone changes aren’t the sole climate consequence affecting plants. Will Criner has been gardening there for 12 years as the garden and facilities manager. In that time, he’s noticed the growing season lengthen and, in turn, the time between the first and last frosts dwindle. “We’re definitely seeing a season extension,” he said. 

“We can be so frustrated, but then [we should] think of it as an opportunity to try something else, to do something new with that space, and not try to fight with the environment.”

While warming temperatures could expand growing ranges for some specialty, high-value crops like oranges, almonds, and kiwis, they could also expand the ranges of pests. In Alaska, for instance, warmer winters have made it easier for the spruce beetle, a native insect capable of decimating entire tree stands, to thrive, Criner said. And Plummer expects that the spotted lanternfly, an invasive species that threatens fruit and hardwood trees in particular, will become a problem in Albany as its range expands northward. 

Warmer temperatures may also make it easier for invasive plant species to establish themselves because they would be able to spread their seeds earlier in the year. Non-native species planted intentionally in gardens may more easily grow out of control, too.

Such non-native species could outcompete other garden plants for water, sunlight, and nutrients, forcing gardeners to change their planting strategies. “I could imagine, as we get longer seasons, that some of these [non-native] plants would have to be removed from our database and deaccessioned” for other plants to thrive, Criner said.

Planting for Precipitation

As the climate warms, gardeners and horticulturists across the country have begun to think about how to better protect their plots. 

In the Midwest, gardeners increasingly face oscillating weather conditions—extreme drought and extreme flooding—that can damage and drown plants. That makes gardening even more of a challenge, Irish-Hanson said. For areas facing intensifying rainstorms, water-loving plants can help mitigate damage to a garden, she said, but they must be planted in low-lying spots to receive adequate water.

These bald cypresses, historically adapted to humid climates of the southeastern United States, have thrived at Pine Hollow Arboretum in Albany, N.Y., for years. The tree to the left, toppled in a March 2024 ice and wind storm, was a white pine, a species indigenous to the region. Credit: Dave Plummer

Plummer, who grew up in Albany, said he’s seen less snow and more ice and wind storms than when he was a child. Those storms can damage plants—a March 2024 ice and wind storm at Pine Hollow Arboretum felled multiple trees, which harmed other specimens. Moving forward, the facility may begin planting species more suited to a warmer climate.

Irish-Hanson recommends gardeners adapt their mindset along with their planting decisions. “Even if we do everything perfectly right and choose the right plant for our environment, it can still die,” she said. “We can be so frustrated, but then [we should] think of it as an opportunity to try something else, to do something new with that space, and not try to fight with the environment.”

Criner has similar advice: “[We should] try to be mindful of the plant choices we make and how plants interact with the surrounding environment, not just if they look pretty or not.”

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

Citation: van Deelen, G. (2025), As climate changes, so do gardens across the United States, Eos, 106, https://doi.org/10.1029/2025EO250203. Published on 28 May 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Source: Geophysical Research Letters

In the Atlantic Ocean, a system of currents carries vast amounts of warm, salty surface water northward. As this water reaches higher latitudes and becomes colder, it sinks and joins a deep, southward return flow. This cycle, known as the Atlantic Meridional Overturning Circulation (AMOC), plays an important role in Earth’s climate as it redistributes heat, nutrients, and carbon through the ocean.

Although scientists know that the strength of the AMOC—meaning how much water it transports—can vary over time and across regions, it has been unclear how changes in AMOC strength at high northern latitudes may or may not be linked to changes farther south.

Petit et al. applied high-resolution climate modeling to uncover connections between AMOC variability at the midlatitude of 45°N and the current’s behavior at higher subpolar latitudes. High-latitude AMOC observations used in the modeling were captured by the Overturning in the Subpolar North Atlantic Program (OSNAP) instrument array, a network of moorings and submersibles deployed across the Labrador Sea between Greenland and Scotland.

The researchers discovered that subpolar AMOC strength, as captured by OSNAP data, does not affect midlatitude AMOC strength. However, they did find that the density of the subpolar AMOC water beginning its journey back southward affected subsequent midlatitude AMOC strength.

Changes in the water’s density at high latitudes appear to be driven by changes in atmospheric pressure that affect wind stress and buoyancy at the sea surface. The team’s analysis indicates that within a time span of 1 year, these subpolar density changes propagate southward along the far western side of the North Atlantic, creating a steeper density gradient at midlatitudes and, ultimately, affecting AMOC strength there.

The findings suggest that OSNAP density measurements could be used to monitor midlatitude AMOC strength. The study’s results could also help inform the design of future ocean-observing systems to deepen understanding of the ocean’s role in Earth’s climate, according to the researchers. (Geophysical Research Letters, https://doi.org/10.1029/2025GL115171, 2025)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2025), Water density shifts can drive rapid changes in AMOC strength, Eos, 106, https://doi.org/10.1029/2025EO250202. Published on 28 May 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.

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

Over the last 24 hours there have been further developments in the situation on the slopes above Blatten in Switzerland, with attention continuing to focus primarily on the Birch Glacier.

Yesterday evening (27 May 2025), the largest collapse to date occurred at the front of the glacier – as a reminder, this is currently moving at about 10 metres per day as a result of the loading, estimated at 9 millions tonnes, from the rockslide debris. The toe of the glacier abuts a steep slope, so these movements render it inevitable that collapses will occur.

There is a wonderful set of drone footage of the situation that has been posted to Youtube by Pomona Media:-

This still, from the Pomona Media video, captures the situation beautifully:-

The current situation on the Birch Glacier at Blatten. Note the rockslide in the background, the huge volume of debris on the ice at the bottom of this slope, the ice of the glacier itself and the steep lower slope down which collapses are occurring. Still from a drone video posted to Youtube by Pomona Media.

The active rock slope is very clearly visible in the background, with some dust from ongoing collapses. The huge volume of debris sitting on the glacier is evident in the middle of the image, with the ice of the mobile glacier in the foreground, above the steep lower slope.

The start of the video, which captures a small collapse, also shows the heavy fracturing in the ice:-

The current situation on the Birch Glacier at Blatten, showing the heavy fracturing in the ice of the Birch Glacier. Still from a drone video posted to Youtube by Pomona Media.

RTS has a nice article reviewing the situation. This includes a video that captures one of the major collapses of the front of the glacier – it is rather spectacular.

There are probably three central scenarios at this point (to be clear, this is my interpretation, not that of the team on-site), although of course reality is rather more messy that this in general:-

1. A further major collapse from the Kleine Nesthorn mobilises the debris on the glacier, and the glacier itself, to generate a major flow. This is probably the worst case scenario, but the likelihood looks to be lower than it was a week ago.
2. The glacier itself collapses, creating a rock and ice avalanche, which cascades down the slope. This would be a major event, but would have the advantage of removing the hazard. There would be a risk to some of the houses in Blatten.
3. There are continued smaller (although not trivial) collapses of the front of the glacier. This could continue for some time until a new equilibrium is reached. This is the scenario that leads to the lowest probability of damage, but it is also means that the risk to the village lasts longer.

I have no means to assess the likelihood of each of the above (and there will be other scenarios in play), but for me (based purely on experience) the most likely at this point is scenario 3.

At the time of writing, it is beautiful morning at Blatten, so the webcam is capturing good images.

As always, it is easy to fixate on the natural processes occurring above Blatten, but this is a very human story too. The population of the village is displaced indefinitely, with the possibility of losing their houses to the disaster. Fortunately, domestic property insurance in Switzerland includes a natural perils pool, so losses to a landslide are likely to be covered (this would not be the case in the UK). This will be of little comfort right now.

But, secondly, the expert team monitoring the slope will also be under immense pressure. They will be getting little sleep at the moment. They are under intense scrutiny, but are also working with many unknowns. No matter how good their data is, it will not be sufficient to accurately anticipate what is going to happen next.

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

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

La integración de energía renovable en redes eléctricas a las escalas necesarias para mitigar las crecientes concentraciones de gases de efecto invernadero en la atmósfera y el calentamiento global requiere un almacenamiento confiable, y en grandes cantidades. Esto se debe a la variabilidad del viento y la radiación solar incidente, que suministran la mayor parte de esta energía. Las cada vez más avanzadas baterías son el medio predilecto para lograr este almacenamiento.

Entra el litio, cuyo peso ligero, alto potencial electroquímico y el alto cociente de carga a peso lo hacen deseable para su uso en baterías para todo, desde aparatos electrónicos hasta vehículos y redes eléctricas. La demanda de este tipo de baterías ha impulsado un crecimiento acelerado de la producción mundial de litio: se estima que en 2023 se produjeron 180,000 toneladas, en comparación con unas 35,000 en la década anterior.

Sin embargo, la comunidad hidrológica ha prestado poca atención a muchas interrogantes científicas relacionadas al agua en la MLL y la CQ.

El litio se extrae principalmente de las rocas del mineral espodumena, por ejemplo, en Australia, y de la salmuera de salares en regiones como la “Media Luna de Litio” (MLL) en Sudamérica y la Cuenca de Qaidam (CQ) en China. En estas dos zonas, tanto los residentes locales como la prensa, las agencias gubernamentales y las organizaciones no gubernamentales están prestando cada vez más atención a los problemas hídricos y ambientales relacionados con la extracción de salmuera, y las tensiones con las empresas mineras son cada vez más públicas.

Sin embargo, la comunidad hidrológica ha prestado poca atención a muchas interrogantes científicas relacionadas al agua en la MLL y la CQ. Estas preguntas involucran la conectividad natural y el transporte de los recursos hídricos regionales, y cómo el clima y las operaciones mineras afectan su cantidad y calidad. Hidrólogos, hidrometeorólogos e hidrogeólogos deberían trabajar para responder a estas preguntas y ofrecer una visión más integral de cómo se puede lograr una extracción de salmuera más sostenible mediante tecnologías y métodos de estudio consolidados, esto consultando con residentes, gobiernos e industrias de extracción de minerales.

Litio de una media luna y un cuenco

La MLL y la CQ, que respectivamente son la segunda y la primera mesetas más grandes del mundo, son cuencas endorreicas áridas, lo que significa que están hidrológicamente desconectadas del océano. Existen numerosos lagos salados en ambas regiones, con superficies que varían de 1 a 10,000 kilómetros cuadrados en la MLL y de menos de 1 a más de 600 kilómetros cuadrados en la CQ. Los lagos obtienen agua dulce del flujo fluvial proveniente de los glaciares, la nieve y la lluvia en las montañas adyacentes, así como del agua subterránea alimentada por el flujo de ríos y la precipitación. La principal vía de salida del agua de estas cuencas es la evapotranspiración, que con el tiempo concentra las sales minerales en depósitos en el fondo de la cuenca, lo que posibilita la extracción de salmuera.

Las fuentes de litio provenientes de salmueras en la región fronteriza entre Bolivia, Argentina y Chile, en la meseta andina (Figura 1, izquierda), la denominada Media Luna de Litio (un área más pequeña dentro de la MLL se conoce comúnmente como el Triángulo del Litio), representan aproximadamente el 53 % de las reservas mundiales conocidas de litio [Steinmetz y Salvi, 2021]. Esta región también produce aproximadamente un tercio de los compuestos de litio a nivel mundial.

China, por su parte, posee alrededor del 6.5 % de las reservas conocidas de litio y contribuyó con cerca del 18 % de la producción mundial de compuestos de litio en 2023. Varias operaciones de extracción de salmuera en China se llevan a cabo en la cuenca del Qaidam, en la provincia de Qinghai, en la meseta tibetana septentrional (Figura 1, derecha). En 2023, el 21.2 % de la producción total de carbonato de litio de China provino de la cuenca del Qaidam [Oficina de Estadísticas de Qinghai, 2023].

Fig. 1. Los contornos rojos indican la ubicación geográfica de la Media Luna de Litio (MLL, izquierda) en la meseta andina de Sudamérica y la Cuenca Qaidam de China (CQ, derecha) en la meseta tibetana septentrional. La MLL tiene elevaciones de 2200 a 6800 metros y una superficie de 327 000 kilómetros cuadrados; la CQ tiene elevaciones de 2600 a 6800 metros y una superficie de 279 000 kilómetros cuadrados. Los contornos de ambas cuencas provienen de HydroBASINS. Haga clic en la imagen para ampliarla. Crédito: datos cartográficos de Google Earth, SIO, NOAA, Marina de los EE. UU., NGA, GEBCO, Landsat, Copernicus, IBCAO

La CQ produce no solo compuestos de litio, sino también potasa, combustibles fósiles, cloruro de sodio y otros recursos que contribuyen significativamente a la industria y la agricultura de China. Por ejemplo, la potasa producida en la QB en 2023 representó el 69.4 % de la producción total de este recurso en China y el 6.5 % de la producción mundial (cifras calculadas con base en datos de la Oficina de Estadística de Qinghai [2023] y del Servicio Geológico de Estados Unidos).

Aumento de demanda en medio de condiciones cambiantes

Las regiones de la MLL y la CQ reciben cantidades similares de precipitación, con promedios anuales totales de aproximadamente 170 a 180 milímetros, que caen principalmente en sus respectivos veranos. Sin embargo, mientras que la precipitación disminuye ligeramente en MLL, esta aumenta gradualmente en CQ (Figura 2). La MLL también es más cálida y húmeda en promedio y presenta una evapotranspiración potencial mucho mayor que CQ; sin embargo, las temperaturas en ambas regiones están aumentando.

Se predice que el almacenamiento de agua disminuirá debido a que el calentamiento podría reducir los glaciares y la nieve en ambas regiones, y estos cambios podrían aumentar la variabilidad de los caudales fluviales y alterar los regímenes de caudal.

Se proyecta que estas tendencias continuarán en las próximas décadas, y los cambios climáticos tendrán consecuencias para los recursos hídricos. Se predice que el almacenamiento de agua disminuirá debido a que el calentamiento podría reducir los glaciares y la nieve en ambas regiones, y estos cambios podrían aumentar la variabilidad de los caudales fluviales y alterar los regímenes de caudal. Junto con el calentamiento, la reducción en precipitación exacerbará las condiciones de sequía en la MLL. En la CQ, el aumento de la precipitación y el derretimiento de los glaciares y la nieve probablemente causarán más eventos extremos compuestos similares a las inundaciones catastróficas que ocurrieron en la región en 2010 [Ma y Xu, 2011] y 2022. Estas inundaciones dañaron campos de salmuera, presas e infraestructura y causaron pérdidas económicas superiores a los 10 millones de dólares.

Mientras tanto, la industria de la extracción de salmuera ha experimentado un auge en las últimas décadas en ambas regiones. Se prevé que la explotación de recursos, especialmente de litio, se intensifique en el futuro próximo, siguiendo la tendencia reciente.

Para extraer los materiales deseados, los mineros perforan pozos en los salares y bombean salmuera rica en minerales a la superficie. La salmuera se deja evaporar durante unos 12 a 18 meses, durante los cuales se evapora aproximadamente el 90 % del agua original. El material restante se recolecta y procesa para obtener productos minerales comercializables. Este proceso de bombeo de salmuera y aumento de la evaporación en la superficie altera los ciclos hidrológicos locales naturales. Además, se necesita agua dulce durante toda la etapa de procesamiento para purificar los compuestos químicos.

Fig. 2. Las gráficas muestran la precipitación anual y la precipitación promedio mensual (Pre), la evapotranspiración potencial (PET), la presión de vapor (VAP) y la temperatura del aire (T) en la MLL y la CQ de 1960 a 2022. Las estrellas indican la significancia de las tendencias con un valor de p < 0.05. Los datos provienen de la Unidad de Investigación Climática TS, versión 4.07. Haga clic en la imagen para verla más grande.

En los últimos años, se han reportado casos que vinculan la extracción de salmuera con la generación de residuos, la contaminación del agua y el suelo, la alteración del paisaje y la degradación de la flora y la fauna, así como con importantes problemas relacionados con la cantidad y la calidad del agua. También se han reportado conflictos y tensiones entre la población local y las empresas mineras en la meseta tibetana y la MLL, relacionados con la reducción de los recursos hídricos y la contaminación de las aguas subterráneas y los caudales fluviales [Marconi et al., 2022; Giglio, 2021].

Los estudios también documentan los efectos en los ecosistemas. Por ejemplo, la reducción de algunas poblaciones de flamencos andinos se correlaciona con un nivel freático más bajo [Gutiérrez et al., 2022], y las poblaciones de cianobacterias que alimentan a los flamencos andinos están disminuyendo en lagunas cercanas al Salar de Atacama en Chile debido al consumo de agua y la contaminación causada por la extracción de litio [Gutiérrez et al., 2018].

La cantidad de agua utilizada en las operaciones de extracción de salmuera puede variar según el clima, las concentraciones minerales y la tecnología empleada, pero para la MLL, los investigadores han estimado que se necesitan entre 100,000 y 800,000 litros de agua por tonelada métrica de litio extraído [Vera et al., 2023]. No existe una estimación similar para la CQ, pero la próspera industria minera en la zona también está aumentando la demanda de agua.

En el sur de la QC, el uso industrial de agua aumentó de 90 millones de metros cúbicos en 2000 a 383 millones de metros cúbicos en 2019, lo que representa el 10.2% y el 40.8%, respectivamente, del consumo total de agua en la región en esos años [Han et al., 2023]. En 2016, se construyeron instalaciones de desviación de agua y canales para transportar agua desde subcuencas cercanas a campos de salmuera y ciudades para satisfacer la creciente demanda. En diciembre de 2023, tres fábricas importantes de extracción de salmuera en la CQ incumplieron sus cuotas de uso de agua al bombear ilegalmente agua subterránea y extraer agua de humedales y lagos protegidos para satisfacer sus demandas de producción. Estas acciones fueron criticadas públicamente por el Ministerio de Ecología y Medio Ambiente de China, que ordenó a las fábricas que dejaran de bombear agua ilegalmente.

Esclareciendo la hidrología en torno a la minería de salmuera

Tenemos un conocimiento limitado del papel de los salares en estos ciclos o de cómo la expansión de las operaciones de extracción de salmuera para satisfacer la demanda de litio podría alterar este papel.

Al igual que el océano y otras reservas de agua debajo, sobre y por encima de la superficie terrestre, los salares del mundo tienen un rol en sus ciclos hidrológicos regionales. Sin embargo, tenemos un conocimiento limitado del papel de los salares en estos ciclos o de cómo la expansión de las operaciones de extracción de salmuera para satisfacer la demanda de litio podría alterar este papel.

Los hidrólogos enfrentan varias preguntas generales: ¿Cómo y en qué medida afecta la extracción de salmuera a los diversos reservorios y flujos (p. ej., recarga de aguas subterráneas, desvío de caudales, evaporación) del ciclo hidrológico regional? ¿Cómo llega la escorrentía superficial de las montañas circundantes a los depósitos de agua subterránea? ¿Cómo se conectan estos depósitos bajo las cuencas desérticas donde se forman los lagos de salmuera? ¿Cuáles son las edades y la composición química de estas aguas subterráneas? Abordar estas preguntas permitirá conocer mejor la cantidad y la calidad de los recursos hídricos disponibles, lo que a su vez ayudará a los responsables de la toma de decisiones a asignar el agua de forma justa a los diferentes sectores y a monitorear y proteger la calidad del agua durante la extracción de salmuera.

Estanques de evaporación en el lecho seco del lago West Taijinai’er en la CQ observados en septiembre de 2023. Crédito: Lan Cuo

Además, debido a que la MLL y la CQ están experimentando un calentamiento similar pero diferentes tendencias de precipitación, y sus respectivos ciclos hídricos regionales pueden, por lo tanto, verse afectados de manera diferente por el cambio climático, los hidrólogos deben explorar preguntas relacionadas con estas diferencias. ¿Cómo responden los glaciares y la nieve en estas regiones al calentamiento emparejado con más (o menos) precipitación? ¿Y cómo responden los regímenes de caudal (que comprenden las magnitudes, los tiempos, las frecuencias y las duraciones de los caudales altos y bajos) a los cambios en los glaciares, la nieve y la precipitación? ¿Qué mecanismos controlan los eventos extremos como sequías e inundaciones en estas regiones? Responder a estas preguntas esclarecerá cómo el cambio climático está afectando los escasos recursos hídricos en la MLL y la CQ y puede informar los esfuerzos de mitigación para conservar estos recursos.

Investigar todas estas interrogantes requiere diversos enfoques. Se necesitan mediciones in situ de precipitación, evaporación, glaciares y nieve, así como de aguas subterráneas, lagos, ríos y suelos, para determinar la disponibilidad y calidad de los recursos hídricos en ubicaciones específicas de la MLL y la CQ. Los análisis con isótopos estables y trazadores pueden ayudar a determinar las fuentes y la edad del agua sobre y bajo la superficie terrestre. Las observaciones satelitales de cómo cambian las variables del paisaje, como la desertificación, la superficie lacustre, los glaciares y la nieve, la humedad del suelo y la vegetación, ayudarán a rastrear los efectos del cambio climático y la extracción de salmuera en los recursos hídricos y los ecosistemas. También necesitaremos estudios de modelización hidrogeológica para comprender la hidrología superficial, el almacenamiento y el movimiento de las aguas subterráneas, y cómo se ven afectados por la escorrentía superficial en la MLL y la CQ (se requieren mediciones in situ para validar los estudios satelitales y de modelización).

Además, se debe fomentar la colaboración entre investigadores de ambas regiones para permitir comparaciones detalladas y esclarecer las diferencias y los puntos en común en los problemas hídricos de cada una. Estas colaboraciones también facilitarían el intercambio de mejores prácticas de investigación y posibles soluciones políticas con respecto a la extracción de salmuera y los recursos hídricos.

Involucrar a todas las partes interesadas para obtener mejores resultados

La extracción de salmuera será sostenible sólo cuando las operaciones, desde su inicio hasta su fin, utilicen el agua de manera eficiente, minimicen el daño al medio ambiente, los ecosistemas y las comunidades, y compensen los daños.

Los recursos hídricos en la MLL y la CQ ya se encuentran bajo tensión debido a su ubicación en medio de los desiertos más altos del mundo y a las cambiantes condiciones climáticas. La extracción de salmuera para abastecer de litio y otras materias primas a la transición a energías renovables podría agravar esta tensión. Esta extracción sólo será sostenible cuando las operaciones, desde su inicio hasta su fin, utilicen el agua de manera eficiente; minimicen los daños al medio ambiente, los ecosistemas y las comunidades; y compensen los daños cuando estos ocurran.

La combinación de múltiples enfoques científicos para estudiar la hidrología regional generará un conocimiento holístico e integral de la cantidad y la calidad del agua en estas áreas. Sin embargo, para apoyar la sostenibilidad de la extracción de salmuera y la gestión de los recursos hídricos en la MLL y la CQ, los científicos deben compartir la información y las respuestas obtenidas de estos enfoques con las agencias gubernamentales pertinentes, las empresas mineras y las comunidades locales a través de informes de investigación, conferencias y asambleas públicas que reúnan a estos grupos.

La participación de los miembros de la comunidad contribuirá especialmente a revelar no solo los efectos en la hidrología y los ecosistemas, sino también el costo humano de las actividades mineras y el cambio climático. Y una mejor comunicación entre estos grupos ayudará a los legisladores y reguladores a crear y hacer cumplir normas para regir las operaciones mineras responsables, al tiempo que mitigan los impactos negativos y satisfacen las necesidades de la comunidad.

Referencias

Giglio, E. (2021), Extractivism and its socio-environmental impact in South America: Overview of the “lithium triangle,” Am. Crítica, 5(1), 47–53, https://doi.org/10.13125/americacritica/4926.

Gutiérrez, J. S., J. G. Navedo, and A. Soriano-Redondo (2018), Chilean Atacama site imperilled by lithium mining, Nature, 557, 492, https://doi.org/10.1038/d41586-018-05233-7.

Gutiérrez, J. S., et al. (2022), Climate change and lithium mining influence flamingo abundance in the Lithium Triangle, Proc. R. Soc. B, 289, 20212388, https://doi.org/10.1098/rspb.2021.2388.

Han, J., et al. (2023), The potential analysis of rain-flood resources in the Golmud river catchment based on climate change and human interventions, Qaidam basin [in Chinese], J. Salt Lake Res., 31(4), 30–38.

Ma, S., and L. Xu (2011), 2010 Golmud River flooding analysis, Qinghai Sci. Technol., 1, 38–41.

Marconi, P., F. Arengo, and A. Clark (2022), The arid Andean plateau waterscapes and the lithium triangle: Flamingos as flagships for conservation of high-altitude wetlands under pressure from mining development, Wetlands Ecol. Manage., 30, 827–852, https://doi.org/10.1007/s11273-022-09872-6.

Qinghai Bureau of Statistics (2023), Statistics of national economy and social development in 2023 [in Chinese], m.yicai.com/news/102000260.html.

Steinmetz, R. L. L., and S. Salvi (2021), Brine grades in Andean salars: When basin size matters—A review of the Lithium Triangle, Earth Sci. Rev., 217, 103615, https://doi.org/10.1016/j.earscirev.2021.103615.

Vera, M. L., et al. (2023), Environmental impact of direct lithium extraction from brines, Nat. Rev. Earth Environ., 4, 149–165, https://doi.org/10.1038/s43017-022-00387-5.

Datos de autora

Lan Cuo (lancuo@itpcas.ac.cn), State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Pekín; también en la University of Chinese Academy of Sciences, Pekín

This translation by Nelmary Rodriguez Sepulveda was made possible by a partnership with Planeteando y GeoLatinas. Esta traducción fue posible gracias a una asociación con Planeteando and GeoLatinas.

This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Source: Global Biogeochemical Cycles

Marine life plays a pivotal role in Earth’s carbon cycle. Phytoplankton at the base of the aquatic food web take up carbon dioxide from the atmosphere, convert it to organic carbon, and move it around as they become food for other organisms. Much of this carbon eventually returns to the atmosphere, but some ends up sequestered in the deep ocean via a process called carbon export.

Quantifying carbon export to the deep ocean is critical for understanding changes in Earth’s climate. Measurements in the Southern Ocean, a key region for global ocean circulation and a substantial carbon sink, are especially important but have been sparse, particularly in areas with sea ice that are difficult to access.

To address that gap, Liniger et al. used data from 212 autonomous, floating instruments known as Biogeochemical-Argo (BGC-Argo) floats to estimate carbon export across the Southern Ocean basin. These floats roam the upper 2,000 meters of the ocean, can travel beneath sea ice, and are equipped with sensors that measure physical and biogeochemical properties of seawater.

Though prior studies have used BGC-Argo data to estimate Southern Ocean carbon export, most focused on narrow regions or timescales and excluded sea ice–covered areas. The new analysis uses data collected between 2014 and 2022 by floats scattered across the entire ocean basin, including under sea ice. After developing a novel method to calculate carbon export using the floats’ measurements of sinking particulate organic carbon and dissolved oxygen change over time, the researchers estimated that about 2.69 billion tons of carbon sink to the deep sea each year in the Southern Ocean.

Their findings also suggest that carbon export varies significantly in different parts of the Southern Ocean, with only about 8% occurring in seasonally ice-covered areas. But the researchers say more investigation is needed to clarify the role of the highly active ecosystems in the sea ice zone, especially as climate change drives shifts in sea ice dynamics. (Global Biogeochemical Cycles, https://doi.org/10.1029/2024GB008193, 2025)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2025), Robotic floats quantify sinking carbon in the Southern Ocean, Eos, 106, https://doi.org/10.1029/2025EO250193. Published on 27 May 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.

Smaller rockfalls have reduced the risk of a major rock slope collapse above Blatten, but attention has shifted to the Birch Glacier, which is now moving at 10 metres per day.

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

Over the last few days, the situation above Blatten in Switzerland has developed considerably. The good news is that the rock slope failure has continued to occur as a series of smaller rockfalls, rather than a single very large collapse. This has limited the runout distance of the debris, sparing, at least so far, Blatten itself.

The webcam has been difficult to use due to the cloudy weather, but the view this morning (27 May 2025) shows that the slope has evolved considerably:-

Webcam image from 27 May 2025 showing the deforming slope at Blatten in Switzerland. Image from Bergfex.

Throughout this crisis, Melaine Le Roy has provided excellent updates via his Bluesky account. Embedding Bluesky posts on Wordpress is very hit and miss, but hopefully this will work. If not, please follow the links.

Yesterday, Melaine posted an update provided by Alban Brigger in the regular press conference about the Blatten event:-

#Blatten Press conference Alban Brigger, -glacier front velocity is 2.5-3 m/day. ‘We do not expect an exponential acceleration, as we feared before.’-the amount of debris deposited on the glacier is 3.5 Mm3 = 9 M t. Up to 80 m thick!1/

On a summer day not long ago, 10 people gathered to eat cheese in the name of science. They nibbled on small rounds of Cantal, a firm cow’s milk cheese historically produced in south central France, and evaluated more than 25 attributes spanning color, odor, taste, aroma, and texture. The tasting was just one component of a larger study on the effects of shifting cows’ diets from grass to corn because of industrialization and climate change. The new findings highlight the importance of maintaining at least some grass in cows’ diets.

“Their physiology and digestive tracts are made to digest grass.”

Cows, with their four stomach pouches, are evolutionarily primed to consume grass and extract all the nutrients possible from that roughage. “Cows are herbivores,” said Elisa Manzocchi, a dairy researcher at Agroscope in Posieux, Switzerland, who was not involved in the research. (Agroscope is a Swiss governmental organization devoted to agricultural research.) “Their physiology and digestive tracts are made to digest grass.”

But bovines around the world are increasingly being fed a corn-based diet as industrial-scale farming proliferates—it’s often easier, more efficient, and more scalable to feed cows from a trough rather than allow them to forage in a pasture.

Climate change is also driving that shift. Even in regions that have long turned cows out to green pastures, farmers are facing summertime grass shortages due to droughts. That’s true in Marcenat, the site of an experimental farm run by the National Research Institute for Agriculture, Food and Environment (INRAE), said Matthieu Bouchon, an animal husbandry scientist there. It’s hotter in the summer than it used to be, but there’s still a lot of spring rainfall, he said. “The conditions are perfect for corn cultivation.”

Seeing cornfields in Marcenat, a mountainous region in south central France at an elevation of 1,000 meters, is jarring, Bouchon said. “It’s not something we’re used to.”

Bouchon and his colleagues at INRAE, led by microbiologist Céline Delbès, recently investigated how changing a cow’s diet has a slew of trickle-down effects on the quantity, quality, nutritional value, and flavor of its milk and resultant cheese. Earlier work compared outcomes of grass- and corn-fed diets in cows, Manzocchi said, but this investigation is particularly thorough. “It’s one of the first studies where they looked at many parameters.”

Soil to Grass to Cow to Milk to Cheese

The team focused on 40 Prim’Holstein and Montbéliarde cows, dividing them into two groups: one fed a largely grass-based diet and the other fed a corn-based diet with some access to pasture grass. After 2 months, half of the cows in the first group were switched to a less grass-based diet, and half of the cows in the second group were entirely denied access to pasture grass. The result was a cohort of four bovine groups that for nearly three more months, ate roughly 75%, 50%, 25%, and 0% grazed grass, respectively.

Throughout the experiment, Delbès and her collaborators collected milk samples two times per week (the cows were milked twice per day), soil samples from the pasture grass, and even swabs from the cows’ udders. The goal was to better understand how a dietary shift induced by climate change translates into changes in the attributes of a herd’s milk and, ultimately, cheese. “There were a lot of things in this experiment,” Bouchon said.

The researchers enlisted the help of a cheese-making facility near the farm to produce small rounds of Cantal cheese, each weighing about half a kilogram, using milk from the cows in each of the four groups. The cheeses were aged for 9 weeks before being served to panelists trained in tasting Cantal-type cheeses.

Preserve the Grass

Consistent with previous findings, the researchers found that cheese made from milk from cows fed primarily grass were more flavorful and had higher levels of certain fatty acids compared with cheeses produced from cows primarily fed corn. However, cows fed diets with a higher proportion of grass also yielded less milk relative to the amount of food they consumed, the team noted.

Overall, Delbès and her collaborators found that the shift from a diet of 25% grazed grass to one of 0% grazed grass was more detrimental to a cheese’s nutritional and sensory qualities than the shift from a 75% grazed grass diet to a 50% grazed grass diet.

“It’s surprising that just a quarter of the diet can do so much [to affect] the sensory quality of the cheese.”

The finding suggests that maintaining at least a modicum of fresh grass is critical to ensuring quality cheese, Delbès said.

“It’s surprising that just a quarter of the diet can do so much [to affect] the sensory quality of the cheese,” Manzocchi said. But perhaps that finding should be reassuring to traditional cheese producers who might no longer be able to feed their herds a largely grass-based diet, she added. “Maybe it’s good news.”

Delbès and her team aren’t yet finished with their Prim’Holstein and Montbéliarde herds. Future work will focus on examining how microbes present in the soil and bedding areas of the cows, for example, are correlated with microbes present in the human gut after cheese is consumed.

—Katherine Kornei (@KatherineKornei), Science Writer

28 May 2025: This story has been updated to correct the location of the experimental farm.

Citation: Kornei, K. (2025), Cheese in the time of industrial farming and climate change, Eos, 106, https://doi.org/10.1029/2025EO250198. Published on 23 May 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Source: Geophysical Research Letters

Soil moisture is a key regulator of temperature and humidity, one that’s positioned to be affected substantially by climate change. But despite the importance of soil moisture, efforts to model it involve dozens of poorly constrained parameters, and different models tend to disagree about how soil moisture levels will change in a warming world.

Gallagher and McColl took a “radically simpler” approach and modeled soil moisture solely in terms of precipitation and net surface radiation. The model worked well when tested using both fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis (ERA5) and Coupled Model Intercomparison Project Phase 6 (CMIP6) climate datasets.

That’s surprising, the researchers say, because the simple model excludes measurements that much of the recent literature has focused on: vapor pressure deficit (the difference between the amount of moisture the air has the capacity to hold and the amount it is actually holding) and atmospheric carbon dioxide (CO2) levels. Both are expected to rise alongside greenhouse gas emissions.

The researchers suggest their model still works well because vapor pressure deficit is a poor measure of atmospheric demand for water; net surface radiation, which is included in the model, is a better measure. In regard to CO2, the researchers say that some prior studies have overestimated the role of the gas.

The simple model offers potential answers to two fundamental questions about soil moisture: (1) Why does soil moisture follow a W-shaped longitudinal profile, with high moisture at the equator and poles and low moisture in between, and (2) why does soil moisture increase with warmer temperatures in some locations but decrease in others?

The W-shaped profile may be caused by a combination of precipitation rates and radiation intensity. High precipitation near the equator dominates the model and causes high soil moisture. The midlatitudes and the poles both see moderate levels of precipitation. But the midlatitudes receive more intense radiation than the poles, which leads to comparatively dryer midlatitude soils.

As for the second question, the researchers suggest warming may have varying effects on soil moisture because warming can come with both increased precipitation, which raises soil moisture, and increased net surface radiation, which lowers soil moisture. These two variables balance each other out to different degrees at different locations, meaning that warming sometimes raises soil moisture and sometimes lowers it. (Geophysical Research Letters, https://doi.org/10.1029/2025GL115044, 2025)

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

Citation: Sidik, S. M. (2025), Simplicity may be the key to understanding soil moisture, Eos, 106, https://doi.org/10.1029/2025EO250197. Published on 23 May 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.

The upcoming Atlantic hurricane season will likely have above-normal activity, according to the annual outlook produced by NOAA.

NOAA issues an Atlantic hurricane season outlook each May, using computer models that consider current climate and ocean conditions.

“Everything is in place for an above-average season.”

The agency estimates that this year’s Atlantic hurricane season, which runs from 1 June to 30 November, will have up to 19 named storms and up to 10 hurricanes. Three to five of those hurricanes are projected to reach major hurricane strength (categories 3, 4, and 5).

Between 1991 and 2020, the Atlantic hurricane season featured seven hurricanes on average.

The report predicts a 60% chance of an above-normal season, a 30% chance of a near-normal season, and a 10% chance of a below-normal season.

“Everything is in place for an above-average season,” said Ken Graham, director of the National Weather Service, at a press conference held in Jefferson Parish, La. NOAA selected Jefferson Parish as the location for the announcement to commemorate the 20-year anniversary of Hurricane Katrina.

Above-average Atlantic Ocean temperatures will fuel an above-average Atlantic hurricane season, according to a NOAA report. Credit: NOAA NWS

The above-average activity forecasted by NOAA will be fueled by above-average temperatures in the Atlantic and Caribbean Sea, forecasts for weak wind conditions, and the potential for higher activity of this year’s West African Monsoon.

The NOAA predictions align with predictions from other institutions, including Colorado State University’s (CSU) Tropical Weather and Climate Research Group. CSU’s forecast predicted 9 hurricanes and 17 named storms for the 2025 season, with 4 of those storms predicted to reach major hurricane strength.

Scientists expect the El Niño–Southern Oscillation (ENSO), a climate phenomenon that affects how heat is stored in the oceans, to remain in a neutral condition or transition to La Niña conditions this summer. Such conditions lead to decreased wind shear, which slightly favors hurricane formation.

In 2024, El Niño conditions, along with human-caused climate change, fueled a spike in ocean temperatures that caused a destructive Atlantic hurricane season. Warming oceans fuel stronger hurricanes that bring more heavy rainfall and higher storm surge when they make landfall.

“It takes only one storm near you to make this an active season for you.”

The odds of El Niño developing this year as the hurricane season peaks are low—less than 15%, according to the latest NOAA prediction. While El Niño conditions tend to increase ocean temperatures, El Niño also creates wind shear that breaks up weather patterns, hindering hurricane intensification. If El Niño conditions do return by the fall, the likelihood of hurricane formation could drop. CSU plans to release an updated forecast on 11 June.

At the press conference, NOAA officials asked those in hurricane-prone areas to prepare for the busy season. “A community that is more informed and prepared will have a greater opportunity to rebound quickly from weather and climate related events,” said Cynthia Lee Sheng, president of Jefferson Parish.

Each year, the World Meteorological Organization selects a list of names for the season’s tropical storms. Credit: NOAA NWS

“It takes only one storm near you to make this an active season for you,” said Michael Bell, a meteorologist at CSU and author of the CSU outlook, in a statement.

The above-average season coincides with unprecedented staffing shortages due to layoffs and staff buyouts at NOAA and its National Weather Service (NWS), which issues hurricane and flood warnings and provides critical emergency information during storms. In a 2 May open letter, five former NWS directors said the agency “will have an impossible task” trying to continue its current level of services amid staff and funding cuts.

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

Citation: van Deelen, G. (2025), Busy hurricane season expected in 2025, Eos, 106, https://doi.org/10.1029/2025EO250200. Published on 22 May 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.

Ammonia released from penguin poop helps produce cloud-seeding aerosols in Antarctica, which can affect local climate by increasing cloud formation. The discovery came when scientists measured air downwind of two colonies of Adélie penguins on the tip of the Antarctic Peninsula.

Penguin poop emitted 100–1,000 times baseline levels of ammonia. New aerosol particles formed when that ammonia mixed with sulfur compounds from marine phytoplankton. The research was published in Communications Earth & Environment.

“This shows a deep connection between the natural ecosystem emissions and atmospheric processes, where emissions from both local seabird and penguin colonies and marine microbiology have a synergistic role that can impact clouds and climate,” said Matthew Boyer, a doctoral student in atmospheric science at the University of Helsinki in Finland and lead author of the study.

Strong Whiffs of Ammonia

Although only trace amounts of ammonia exist in Earth’s atmosphere, scientists have found that when it mixes with certain sulfur compounds it creates ultrafine particles (<0.1 micrometer in size). Those aerosols can grow into cloud condensation nuclei.

“Aerosol particles are necessary for cloud formation; liquid water will not condense to form cloud droplets without the presence of aerosol particles,” Boyer explained.

The presence of these aerosols is especially important in pristine environments such as Antarctica that have low background levels of cloud-forming particles.

“The new particle formation process doesn’t strictly need ammonia to proceed, but ammonia boosts the rate of the process considerably—up to 1,000 times faster,” Boyer said. Gases emitted from natural sources such as penguins and the ocean are an important source of aerosols in the region, he added.

But the extremely low concentrations of gaseous ammonia, combined with the remoteness of Antarctica, have made understanding this cloud formation pathway challenging.

To tackle this problem, the researchers set up atmospheric samplers on the ground near Argentina’s Marambio Station, located on Seymour Island near the northernmost tip of the Antarctic Peninsula. Two large colonies of Adélie penguins nested a few kilometers away, one with about 30,000 breeding pairs and another with roughly 15,000 penguin pairs, as well as 800 cormorant pairs.

Researchers put sensors near the main buildings at Marambio Station on Seymour Island. Credit: Lauriane Quéléver

From 10 January to 20 March 2023 (during austral summer), the team measured concentrations of ammonia, fine aerosol particles, and larger cloud condensation nuclei, as well as relative abundance of certain elements, cloud droplet distribution, and other atmospheric properties. By late February, the penguins left their breeding grounds and traveled to their wintering site, enabling the researchers to analyze the atmosphere with and without the birds present.

When wind blew air from the nesting grounds to the monitoring station, the team found that the penguin colonies emitted up to 13.5 parts per billion of ammonia, more than 1,000 times more than background levels without poop. However, when winds blew in from the sea, the Southern Ocean was a “negligible” source of ammonia.

“The footprint of ammonia emissions from penguins may cover more area of coastal Antarctica than indicated by the location of their colonies alone.”

Even after the penguins migrated, the poop they left behind continued to elevate ammonia to 100 times higher than background levels, which was the most surprising discovery for Boyer.

“This means that the footprint of ammonia emissions from penguins may cover more area of coastal Antarctica than indicated by the location of their colonies alone,” he said.

The team found that 30 times more aerosol particles formed when gaseous ammonia mixed with sulfuric gases released by marine phytoplankton. When that combination then mixed with dimethylamine gas, also emitted by penguin poop, aerosol formation increased 10,000-fold.

Gaseous ammonia lasts only a few hours in the atmosphere, but the aerosol particles it creates can survive for several days. Under the right wind conditions, those particles could travel out over the Southern Ocean and generate clouds where cloud condensation nuclei sources are limited.

Climate change threatens the survival of Adélie penguins, but the penguins also help shape their local atmosphere and climate. Credit: Matthew Boyer

The new results align with past research that examined the impact of Arctic seabirds on atmosphere and climate. They also agree with past laboratory and modeling studies of Antarctic cloud formation, which have been considered more reliable in the past than in situ measurements.

“Measuring ammonia on its own under normal circumstances can be tricky,” said Greg Wentworth, an atmospheric scientist with the government of Alberta in Canada who was not involved with the new research. “To do all the sophisticated measurements required to tease apart the details of new particle formation is remarkable, especially since they did this at the ends of the Earth!”

Penguin Feedback Loops

“How remarkable is it that emissions from penguin poop and phytoplankton can kick-start chemistry in the atmosphere that can alter clouds and affect climate?”

“This study provides the most compelling evidence to date that ammonia and sulfur compounds…are an important source of cloud condensation nuclei during summertime in Antarctica,” Wentworth added. “How remarkable is it that emissions from penguin poop and phytoplankton can kick-start chemistry in the atmosphere that can alter clouds and affect climate?”

The polar regions are experiencing dangerous levels of warming, and more cloud cover can help cool things down…sometimes. Higher concentrations of aerosol particles tend to create thicker, low-atmosphere clouds that are more reflective and can cool the surface, Boyer said. Thinner clouds high in the atmosphere tend to trap heat and warm the surface.

Understanding whether seabirds generate aerosols at a consistent, high-enough rate to cool local climate would require more atmospheric monitoring and climate modeling, he added.

A connection between penguins and their environment means that when one is threatened, both feel the impacts. As climate change warms the polar regions and endangers the species that live there, the loss of those species could reduce cloud cover and further accelerate warming.

“It’s important to understand how ecosystems, especially sensitive ones in remote regions, will respond to climate change,” Wentworth said. “It’s doubly important to understand those changes when components of those ecosystems also impact climate change.”

“The more we understand about specific processes that impact ecosystems and climate change, the better we can predict and adapt to change,” Wentworth said.

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

Citation: Cartier, K. M. S. (2025), Pungent penguin poop produces polar cloud particles, Eos, 106, https://doi.org/10.1029/2025EO250201. Published on 22 May 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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

Early on 22 May, the U.S. House of Representatives passed a massive GOP-backed bill that seeks to push forward President Trump’s domestic policy agenda. Within the bill’s 1,082 pages are sweeping repeals of regulations that defend the environment, mitigate climate change, and protect public health.

 
Related

•  Here’s What’s in the GOP Megabill that’s Just Passed the House
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•  Get Involved: AGU Science Policy Action Center
 

In their place, the bill promotes fossil fuel production and burning; scales back safety net programs such as Medicaid and supplemental nutrition and assistance program (SNAP); rescinds funds and blocks plans for natural resource management; reforms student loan lending and repayment; advances aggressive anti-immigration policies; and funds tax cuts for the ultra-wealthy.

Some of the Earth science-related provisions in the bill would:

• Rescind unused funding allocated to maintain facilities for NOAA and the National Marine Sanctuary;
• Bring an earlier end to clean energy tax credits and subsidies provided under the Inflation Reduction Act;
• Repeal rules related to vehicles’ greenhouse gas emissions and vehicle fuel economy standards;
• Rescind Clean Air Act funds related to environmental and climate justice, as well as other funds meant to reduce or regulate greenhouse gas emissions, improve air quality at schools, and require businesses to publicly report their carbon footprints;
• Rescind funds that would have invested in coastal communities to build climate resilience, and that helped U.S. Forest Service and the National Park Service protect federal land;
• Interfere with several states’ plans to manage their own resources, including in Wyoming, Montana, North Dakota, and along the Colorado River;
• Enhance timber production and logging on National Forest Service lands and allow mineral mining in Alaska to move forward.

The bill passed by a 1-vote margin in the House (215-214). It now moves to the Senate, where it is expected to face additional opposition from the Democratic Party and GOP deficit hawks.

—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 © 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.

Eos is welcoming June (that’s National Ocean Month in the United States) with a rhyming tradition of something old, something new, something borrowed, and something blue.

Our “something old” is the spectacularly upgraded, 60-years-young Alvin, probably the world’s most famous human-occupied deep-sea submersible. Alvin can now dive to 6,500 meters—a full 2,000 meters more than its previous limit—and explore 99% of the seafloor. Read all about it in “An Upgraded Alvin Puts New Ocean Depths Within Reach.”

“Something new” is the two-vehicle fleet of midsize remotely operated vehicles (mROVs) that will join the U.S. Academic Research Fleet. The mROVs will “fill the niche between large, work-class vehicles such as Jason and small vehicles used primarily for observation.”

“Something borrowed” is time on the JOIDES Resolution (JR), the legendary research vessel that retired last year. In this month’s opinion, three early-career researchers share what they learned, from sediment cores to transdisciplinary collaboration, as part of the JR’s final voyage.

Something blue? That’s the deep blue sea, of course. Dive in!

—Caryl-Sue Micalizio, Editor in Chief

Citation: Micalizio, C.-S. (2025), Submerged in science, Eos, 106, https://doi.org/10.1029/2025EO250199. Published on 22 June 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.