EOS

Antarctica is Earth’s most remote continent, barely touched by human activities.

It is, however, not immune to the kind of environmental damage that plagues more populated parts of the world. In a new study, researchers found chemicals originating from everyday personal care products (PCPs), such as cosmetics, detergents, pharmaceuticals, and deodorants, in Antarctic snow.

Contaminants in PCPs—loosely defined as semivolatile organic compounds that are industrially produced at a global scale, used in large volumes, and relatively persistent in the environment—are increasingly being recognized as pollutants. Both the Arctic Monitoring and Assessment Programme and the Scientific Committee on Antarctic Research have encouraged further research on PCP ingredients and the creation of monitoring plans for tracking their presence at the poles.

Looking for these pollutants, researchers collected 23 surface snow samples from 18 sites along the Ross Sea coast during the Antarctic summer of 2021–2022. Though some sampling locations were near areas with human activity, including Italy’s seasonally occupied Mario Zucchelli research station, the majority were situated hundreds of kilometers from human settlements.

The scientists reached these remote locations by piggybacking on helicopter rides transporting other teams maintaining weather stations or deploying scientific instruments. “This way we halved the impact of our sampling, because they needed to go there in any case,” said Marco Vecchiato, an analytical chemist at Ca’ Foscari University in Venice, Italy, who led the study.

Back in Italy, Vecchiato and his colleagues analyzed the snow samples under clean-room conditions to prevent contamination.

“This very different behavior during the season means that [PCPs] are very sensitive to the environmental conditions.”

They found PCP chemicals in every sample, with varying chemical concentrations suggesting different capacities for atmospheric transport. Of the 21 chemicals analyzed, three compound families were particularly notable. Salicylates, commonly used as preservatives in cosmetics (including lotions, shampoos, and conditioners) and pharmaceutical products, were the most prevalent, followed by UV filters associated with sunscreens. Fragrances such as musks were also detected.

Most of these substances were dissolved in the snow. The UV filter octocrylene, however, which has been associated with coral reef damage and banned in places like the U.S. Virgin Islands and Palau, was found bound to solid particles within the snow.

The researchers observed an unexpected seasonal variation in the amount of PCPs within the samples: Samples collected later in the summer had about 10 times higher PCP levels than those collected earlier in the season, though the relative proportions of each pollutant within a sample remained consistent.

Seasonal fluctuation suggests that Antarctic summer air circulation plays a role in transporting pollutants from distant sources to the continent’s interior. During summer, oceanic winds blowing inland dominate over winds originating from the polar plateau, which are stronger during the rest of the year. That shift may push pollutants far inland.

“This very different behavior during the season means that [PCPs] are very sensitive to the environmental conditions,” Vecchiato said.

One of the researchers presented the team’s preliminary findings at the European Geosciences Union General Assembly in May, and the scientists have a more comprehensive analysis currently underway, according to Vecchiato.

A Local or Distant Source

Finding organic pollutants in seemingly pristine polar environments isn’t surprising. In the 1960s, scientists found large concentrations of persistent organic pollutants (POPs), including the widely used pesticide DDT (dichlorodiphenyltrichloroethane), in Antarctica. POPs don’t degrade naturally and travel thousands of kilometers through the atmosphere, with some eventually getting trapped in snow and ice. Permanently frozen places such as glaciers and polar regions become natural traps. Starting in the early 2000s, the United Nations’ Stockholm Convention on Persistent Organic Pollutants established international cooperative efforts to eliminate or restrict the production and use of POPs.

Though they might travel by a mechanism similar to that used by persistent organic pollutants, unlike POPs, PCPs “do break down in the environment,” said Alan Kolok, a professor of ecotoxicology at the University of Idaho. However, “if those fragrances are not coming from the [research] stations themselves,” he asked, “where are they coming from?”

“Thousands of people are currently accessing the Antarctic continent, and my conclusion is that wherever we humans go, we bring contaminants.”

To rule out a local origin for the PCP pollutants, researchers analyzed sewage from the Mario Zucchelli research station. The outpost did contribute some pollution, but the relative abundance of each compound in the sewage differed from that found in the snow, suggesting that the PCPs detected in the broader Antarctic environment likely originated from more distant sources.

“My suspicion is that for these types of compounds—personal care products, pharmaceutical products—there must be a local source,” said Ricardo Barra Ríos, an environmental scientist at the Universidad de Concepción in Chile who has analyzed PCP pollution in Antarctic coastal waters related to research stations. “Thousands of people are currently accessing the Antarctic continent, and my conclusion is that wherever we humans go, we bring contaminants.”

Vecchiato disagreed. In a separate study published earlier this year, he and other colleagues found PCPs, including fragrances and UV filters, in the snows of the Svalbard archipelago in the Arctic. In that study, the researchers linked the presence of these compounds to atmospheric patterns that carried pollution from northern Europe and the northwestern coast of Russia.

“Most of these contaminants should have a limited mobility, but actually, we found them in remote regions,” Vecchiato said. “Does that mean that the models are wrong or that our analysis is wrong?” he asked. “No, probably we are missing a piece [of the puzzle], or maybe the use of these contaminants is so huge that we still have a relevant concentration in remote areas, even if they should not be prone to this kind of transport.”

—Javier Barbuzano (@javibar.bsky.social), Science Writer

Citation: Barbuzano, J. (2025), Is your shampoo washing up in Antarctica?, Eos, 106, https://doi.org/10.1029/2025EO250209. Published on 3 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.

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

En 2017, Paulo Tarso Oliveira, profesor de hidrología en la Universidad de São Paulo, se encontró con una noticia sobre una pequeña aldea a orillas del río São Francisco, uno de los principales ríos del noreste de Brasil. El artículo informaba que los habitantes estaban presentando tasas inusualmente altas de hipertensión arterial, y relacionaba esta anomalía con el clima seco de la región y el bajo caudal del río. A medida que el nivel freático descendía, el agua oceánica comenzaba a infiltrarse hacia el agua subterránea de la región, elevando los niveles de sal en el suministro y provocando problemas de salud entre la población.

“Muchas veces, la gente no se da cuenta, pero las aguas superficiales y subterráneas están conectadas y deben considerarse como un todo”.

Intrigado, Oliveira investigó más a fondo. Más adelante descubrió que el flujo del río estaba disminuyendo porque los pozos estaban extrayendo agua del acuífero subyacente. “Muchas veces, la gente no se da cuenta, pero las aguas superficiales y subterráneas están conectadas y deben considerarse como un todo”, señaló Oliveira.

En lugares donde el nivel freático se encuentra bajo el lecho de un río, el río puede filtrar agua hacia el acuífero subyacente. Este proceso, conocido como filtración del caudal fluvial, ocurre de forma natural dependiendo de las formaciones geológicas subyacentes y los niveles de agua subterránea. Sin embargo, la construcción de pozos que extraen agua en exceso de los acuíferos puede intensificar este fenómeno.

Oliveira y sus colegas descubrieron que la situación en la cuenca del São Francisco no es un caso aislado. Al evaluar pozos en todo Brasil, los investigadores encontraron que en más de la mitad de ellos el nivel del agua estaba por debajo del nivel de los arroyos cercanos.

Mapeo de pozos

En 2023, Oliveira y el estudiante de maestría José Gescilam Uchôa comenzaron a mapear los ríos de Brasil para identificar zonas en riesgo de pérdida de agua. Se basaron en datos públicos sobre niveles de ríos y ubicación de pozos, proporcionados por el Servicio Geológico de Brasil. Sin embargo, la mayoría de los pozos registrados carecían de información suficiente. Como resultado, se enfocaron en 18,000 pozos con datos completos, distribuidos a lo largo de miles de ríos en el país.

Los investigadores compararon el nivel del agua en cada pozo con la elevación del arroyo más cercano. En el 55 % de los casos, el nivel del agua en los pozos era inferior a la elevación de los arroyos vecinos.

José Uchôa realiza mediciones en un río de São Paulo. Crédito: Laboratorio de Hidráulica Computacional, Universidad de São Paulo

“Nuestros datos sugieren que el uso de aguas subterráneas está afectando significativamente el caudal de los ríos”, señaló Uchôa. “Este es, y seguirá siendo, un motivo de creciente preocupación para la gestión del agua en el país”.

El estudio, publicado en Nature Communications, también identificó regiones críticas, incluida la cuenca del São Francisco, donde más del 60 % de los ríos podrían estar perdiendo agua debido a la intensa extracción subterránea. Esta extracción se asocia principalmente con actividades de irrigación.

En la cuenca del Verde Grande, en el este de Brasil, donde la irrigación representa el 90 % del consumo de agua, el 74 % de los ríos podrían estar perdiendo agua hacia los acuíferos.

Oliveira considera que los resultados son conservadores y que la situación podría ser aún peor, ya que los investigadores no tomaron en cuenta los pozos ilegales. Un estudio realizado en 2021 por el geólogo Ricardo Hirata, de la Universidad de São Paulo, estimó que alrededor del 88 % de los 2.5 millones de pozos en Brasil son ilegales, al carecer de licencia o registro para operar.

Hirata, quien no participó en la nueva investigación, advirtió que el estudio se basó únicamente en el 5 % de los pozos existentes, ubicados principalmente en regiones donde la explotación de aguas subterráneas es más intensa.

“Quizá esto también esté ocurriendo en otras regiones del país con alta demanda de irrigación, y simplemente no lo sabemos por falta de datos”.

Hirata también subrayó que, aunque los investigadores identificaron ríos que potencialmente están perdiendo agua hacia los acuíferos, esos datos por sí solos no son suficientes para determinar si los ríos realmente se están secando. Para evaluar eso, se deben considerar otros factores, como la cantidad de agua extraída del acuífero en comparación con el caudal del río, el grado de conexión entre el acuífero y el río, y cuánta agua se extrae del acuífero en relación con las variaciones estacionales del caudal.

“El hecho de que el nivel de agua de un pozo esté por debajo del de un río cercano no necesariamente afecta al río o al acuífero”, explicó Hirata.

Las áreas identificadas como críticas por el estudio se ubican principalmente en regiones áridas, donde ya se esperaba que ocurriera filtración del caudal de manera natural, señaló André F. Rodrigues, hidrólogo de la Universidad Federal de Minas Gerais, quien no participó en la investigación.

El estudio es relevante porque resalta un problema creciente, dijo Rodrigues, pero se necesitan análisis más locales para obtener una imagen más detallada del problema y considerar, por ejemplo, los efectos del clima y los cambios estacionales. “Quizá esto también esté ocurriendo en otras regiones del país con alta demanda de irrigación, y simplemente no lo sabemos por falta de datos”, comentó.

Un problema en crecimiento

La expansión descontrolada de pozos y la extracción excesiva de agua subterránea no solo afectan la salud de las personas, el abastecimiento de agua y la agricultura, sino que también pueden desestabilizar el suelo, provocando hundimientos (subsistencia). Fenómenos similares se han observado en regiones de China, Estados Unidos e Irán.

El panorama no es nada alentador para Brasil. Es probable que la cantidad de pozos se multiplique, ya que se espera que las áreas de riego se incrementen en más del 50 % en los próximos 20 años, según la agencia nacional del agua de Brasil.

“Probablemente veremos un círculo vicioso de degradación, en el que la disminución en la cantidad y calidad del agua superficial, combinada con el aumento de los períodos de sequía, obligará a los agricultores a perforar más pozos para mantener la producción de alimentos, intensificando aún más la extracción de aguas subterráneas y agravando el problema”, advirtió Oliveira.

La sobreexplotación de aguas subterráneas es una preocupación a nivel mundial. La mayoría de los acuíferos han mostrado un descenso en lo que va del siglo XXI, y los estudios por modelado sugieren que la filtración de caudales será más común en las próximas décadas. Aun así, este problema ha sido en gran medida ignorado en regiones tropicales como Brasil, que alberga el 12 % de los recursos de agua dulce renovables del planeta.

Esta falta de atención se debe en parte al escaso financiamiento y vigilancia, y en parte a una creencia persistente de que en los países tropicales y húmedos los ríos suelen ganar agua de los acuíferos y no perderla, mencionó Oliveira. “Debemos actuar ahora si queremos evitar que regiones enteras queden devastadas en el futuro”.

Los investigadores hacen un llamado a realizar más estudios y establecer un monitoreo sistemático de los pozos para identificar las zonas más secas y evaluar el impacto de nuevos pozos sobre los ríos. Actualmente, Brasil solo cuenta con 500 pozos de observación monitoreados constantemente por el gobierno, en comparación con los 18,000 que existen en Estados Unidos, a pesar de que ambos países tienen extensiones territoriales similares. “La vigilancia es extremadamente importante y está tremendamente subestimada”, enfatizó Uchôa.

—Sofia Moutinho (@sofiamoutinho.bsky.social), Escritora de ciencia

This translation by Saúl A. Villafañe-Barajas (@villafanne) was made possible by a partnership with Planeteando and Geolatinas. Esta traducción fue posible gracias a una asociación con Planeteando y Geolatinas.

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.

Rock glaciers are debris landforms found in many mountain ranges on Earth. They represent the movement of permanently frozen ground over long periods of time and can be used to understand how climate change is affecting permafrost.  

A new article in Reviews of Geophysics explores the use of “Rock Glacier Velocity” to measure how fast these landforms move each year, and its relationship with climatic factors. Here, we asked the authors to give an overview of Rock Glacier Velocity, how scientists measure it, and what questions remain.

What makes rock glaciers unique landforms? 

Rock glaciers primarily form where the ground temperature ranges from approximately -3 to 0°C. Generated by gravity-driven deformation of permafrost, rock glaciers exhibit distinct morphologies indicative of a cohesive flow. The motion mechanism, known as rock glacier creep, involves shearing in one or more layers (i.e., shear horizons) at depth within the permafrost and deformation of the frozen materials above. Changes in rock glacier creep rates depend primarily on changes in ground temperature. Rock glaciers provide a unique opportunity to indirectly document the evolution of permafrost temperatures in mountainous regions.

Remote sensing and field photos of rock glaciers. Credit: Hu et al. [2025], Figure 1

What is “Rock Glacier Velocity” and why is it important to measure? 

“Rock Glacier Velocity (RGV)” refers to the time series of annualized surface velocity reflecting the movement related to rock glacier creep. Since 2022, RGV has been accepted by the Global Climate Observing System (GCOS) as an Essential Climate Variable (ECV) Permafrost Quantity. An ECV is defined as “a physical, chemical, or biological variable (or group of linked variables) that is critical for characterizing the Earth’s climate.” An ECV Quantity is a measurable parameter necessary for characterizing an ECV. Rock Glacier Velocity is instrumental in assessing the state of permafrost under climate change, especially in places where direct monitoring is scarce. From a climate-oriented perspective, relative changes in Rock Glacier Velocity are significant.

What are the main factors that control Rock Glacier Velocity? 

Rock Glacier Velocity is collectively controlled by the geomorphologic features such as slope and landform geometry, as well as the thermo-mechanical properties of the frozen ground, such as ice content, subsurface structure, temperature, and the presence of unfrozen water under permafrost conditions. On a given rock glacier, relative changes in surface velocity over time usually reflect the climatic impacts, with temperature forcing being the dominant factor, especially when temperatures approach 0°C.

How do scientists observe and monitor Rock Glacier Velocity at different spatial scales? 

An illustration showing different survey methods for quantifying Rock Glacier Velocity. Credit: Hu et al. [2025], Figure 5a

Rock Glacier Velocity can be observed and monitored using in-situ and remote sensing methods. Global Navigation Satellite System (GNSS), theodolite, and total station surveys, provide point-based in-situ measurements. Regional-scale surveys typically employ remote sensing techniques, such as laser scanning, photogrammetry, radar interferometry, and radar offset tracking. In-situ RGV time series’ are rare and have mostly been provided from the European Alps, but they can be more than 20 years long. The goal is to leverage the experience gained from the systematic compilation of those in-situ time series to expand the RGV collection to regional-scale surveys using remote sensing techniques.

What kinds of patterns have been observed in Rock Glacier Velocity? 

According to the Rock Glacier Velocity data from across the European Alps, rock glaciers have generally accelerated alongside increasing air temperatures over the past three decades. At the interannual scale, RGV exhibits a regionally synchronous pattern with distinct acceleration phases (i.e., 2000–2004, 2008–2015, and 2018–2020) which are interrupted by deceleration or a steady kinematic state. However, systematic monitoring and documentation of Rock Glacier Velocity is currently lacking in many parts of the world.

How is climate change expected to influence Rock Glacier Velocity? 

Among the climatic factors, multi-annual air temperature changes primarily influence Rock Glacier Velocity by altering the ground thermal state of rock glaciers. Snow cover acts as an insulating layer whose development varies from year to year, causing the ground temperature to deviate from the air temperature on an interannual scale.

In general, warmer ground temperatures favor rock glacier movement. This pattern is expected to occur in many rock glaciers in the future as the climate continues to warm.  When the ground temperature reaches 0°C, some rock glaciers experience drastic acceleration. However, consequent thawing at the tipping point of 0°C causes the rock glacier creep to decline.

What are some of the remaining questions where additional modeling, data, or research efforts are needed? 

First, a standardized strategy for monitoring Rock Glacier Velocity using different methods is under development. We call for more systematic and consistent velocity measurements that can be used to generate Rock Glacier Velocity data products.

Second, the mechanisms linking climatic factors to Rock Glacier Velocity still need to be explored further, such as whether water infiltrates the partially frozen body of a rock glacier and how cold temperatures influence winter deceleration.

Additionally, an in-depth understanding of the relationship between Rock Glacier Velocity, environmental factors, and permafrost conditions requires observations combined with laboratory work and numerical modeling. This is necessary in order to incorporate rock glacier processes into land surface models and predict future changes in a warming climate.

—Yan Hu (huyan@link.cuhk.edu.hk, 0000-0001-8380-276X), University of Fribourg, Switzerland; and Reynald Delaloye (0000-0002-2037-2018), University of Fribourg, Switzerland

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: Hu, Y., and R. Delaloye (2025), Rock Glacier Velocity: monitoring permafrost amid climate change, Eos, 106, https://doi.org/10.1029/2025EO255017. Published on 3 June 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.

Nine people have been killed in a series of landslides, triggered by heavy rainfall, that have struck an army camp.

At about 7 pm local time on 1st June 2025, a series of landslides struck an army camp at Chaten in the Lachen District of Sikkim in India. It is believed that nine people have been killed, although at the time of writing six of these people were still missing, including an army officer, his wife and daughter.

Chaten is located at [27.7188, 85.5581]. This is a Google Earth image of the site, collected in March 2022:-

Google Earth image of the site of the 1 June 2025 landslide at Chaten in Sikkim, India.

The best imagery of the landslides that I have found is on a Youtube video posted by Excelsior News:-

This still captures the site well:-

The 1 June 2025 landslides at Chaten in Sikkim, India. Still from a video posted to Youtube by Excelsior News.

The image shows two main landslide complexes (plus one in the background). Each consists of a series of shallow slips on steep terrain – the one on the left has at least three initial failures, on the right there are also at least three). These have combined to create open hillslope landslides that have stripped the vegetation and surficial materials. Note the very steep lower slopes to the river.

These shallow landslide complexes are characteristic of extremely intense rainfall events, which saturate the soil and regolith from the boundary with the underlying bedrock. This causes a rapid loss of suction forces and a reduction in effective stress, triggering failure. The high water content of the soil then promotes mobility.

It is interesting to note that the natural vegetation has been removed from these slopes. It would be premature to assert that this was an underlying cause of the landslides, but it may have been a factor.

It appears that there has also been erosion of the riverside cliffs, which has left other parts of the camp in severe danger.

Sadly, given the terrain and the availability of people to participate in a rescue (which is one advantage of an event in an army camp), the prospects for those who are missing are not postive.

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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.

In a move that worried politicians and space scientists alike, President Trump announced on 31 May that he will withdraw his nomination of Jared Isaacman for the position of NASA administrator, according to Semafor. Isaacman’s nomination received bipartisan support and he was expected to easily pass a Senate confirmation vote in a few days.

 
Related

•  White House to pull NASA nominee Isaacman
•  Trump withdraws Jared Isaacman’s nomination as NASA administrator
• The Planetary Society reissues urgent call to reject disastrous budget proposal for NASA
• Get Involved: AGU Science Policy Action Center

This is seismic.Isaacman had clearly articulated a strong support for science, and the withdrawal of his nomination yet further imperils NASA's Science Mission Directorate.www.semafor.com/article/05/3…

— Paul Byrne (@theplanetaryguy.bsky.social) 2025-05-31T20:49:52.860Z

Trump cited a “thorough review of prior associations” as the reason for withdrawing the nomination. It was not immediately clear whether he was referring to Isaacman’s past donations to Democrats or his ongoing associations with former DOGE head and SpaceX CEO Elon Musk, who spent the weekend distancing himself from the president. Both of these associations were public at the time of Isaacman’s nomination.

Isaacman, a billionaire, private astronaut, and CEO of credit processing company Shift4 Payments, was questioned by the Senate Committee on Commerce, Science, and Transportation in a nomination hearing in April. Despite a few contentious moments regarding Isaacman’s association with Musk and some waffling over NASA’s Moon-to-Mars plan, the committee ultimately approved Isaacman’s nomination with strong bipartisan support.

When Trump announced Isaacman’s nomination in December 2024, very early for a NASA administrator, space scientists greeted the news with cautious optimism. Isaacman had vocally expressed support for the imperiled Chandra X-ray Observatory, and is a known space enthusiast.

Now, with the withdrawal of his nomination just days after a president’s budget request that would devastate Earth and space science, scientists fear for the future of NASA.

—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
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Source: AGU Advances

In the southern flanks of the Indian Ocean and the central and eastern Pacific, just north of the Antarctic Circumpolar Current, lie the Subantarctic Mode Waters. As part of the global ocean conveyor belt, these large masses of seawater transfer substantial amounts of heat and carbon northward into the interiors of the Indian and Pacific Oceans. These waters hold about 20% of all anthropogenic carbon found in the ocean, and their warming accounted for about 36% of all ocean warming over the past 2 decades—making them critical players in Earth’s climate system.

Prior research has suggested Subantarctic Mode Waters form when seawater flowing from warm, shallow subtropical regions mixes with water flowing from cold, deep Antarctic regions. But the relative contributions of each source have long been debated.

Fernández Castro et al. used the Biogeochemical Southern Ocean State Estimate model to investigate how these water masses form. The model incorporates real-world physical and biogeochemical observations—including data from free-roaming floats—to simulate the flow and properties of seawater. The researchers used it to virtually track 100,000 simulated particles of water backward in time over multiple decades to determine where they came from before winding up in Subantarctic Mode Waters.

The particle-tracking experiment confirmed that subtropical and Antarctic waters indeed meet and mix in all areas where Subantarctic Mode Waters form but offered more insight into the journeys and roles of the two water sources.

In the Indian Ocean, the simulations suggest, Subantarctic Mode Waters come mainly from warm, shallow, subtropical waters to the north. In contrast, in the Pacific Ocean, Subantarctic Mode Waters originate primarily from a water mass to the south known as Circumpolar Deep Water.

Along their southward flow to the subantarctic, subtropical waters release heat into the atmosphere and become denser, while ocean mixing reduces their salinity. Meanwhile, the cooler Circumpolar Deep Water absorbs heat and becomes fresher and lighter as it upwells and flows northward from the Antarctic region to the subantarctic.

These findings suggest that Subantarctic Mode Waters affect Earth’s climate differently depending on whether they form in the Indian or Pacific Ocean—with potential implications for northward transport of carbon and nutrients. Further observations could help confirm and deepen understanding of these intricacies. (AGU Advances, https://doi.org/10.1029/2024AV001449, 2025)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2025), On the origins of Subantarctic Mode Waters, Eos, 106, https://doi.org/10.1029/2025EO250207. Published on 2 June 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
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The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.

On 30 May 2025, a rock slope major failure occurred at a quarry at Gunung Kuda, which is located on the edge of Cipanas Village in Dukupuntang District, Cirebon Regency, West Java, Indonesia. At the time of writing, it has been confirmed that 19 people were killed in the accident, with a further six people remaining missing. Four people were injured.

The location of the failure is [-6.7754, 108.4022]. This is the site in Google Earth:-

Google Earth image of the site of the 30 May 2025 landslide at Gunung Kuda mine.

Universitas Siber Asia has a good article about the event, in Indonesian but it translates well. There is also some Youtube footage of the site immediately after the failure:-

There are other videos circulating of a dramatic rock slope failure, but the ones that I have seen are not this event.

There is also some very clear drone footage of the site after the failure:-

This includes this view of the landslide:-

Drone footage of the site of the 30 May 2025 landslide at Gunung Kuda mine. Still from a video posted to Youtube by Andrea Ramadhan.

The geological structure of this quarry is very complex, with many joints being visible in the above image that would promote instability.

The Universitas Siber Asia article describes a site with a very poor history regarding instability:-

“The Geological Agency said the mine location was in a zone of high soil movement vulnerability, with a probability of landslide of more than 50%. The Head of the West Java Energy and Mineral Resources Office, Bambang Tirto Mulyono, stated that the main cause was the wrong mining method, namely digging from under the cliff, making the soil structure fragile. Repeated warnings from the Energy and Mineral Resources and police lines since February 2025 have been ignored by mine managers. As a result, the West Java Provincial Government revoked the mining permit that was supposed to be valid until October 2025 and closed the site permanently.”

Interestingly, the quarrying was licensed, albeit with substantial safety concerns. Detik Jabar describes the long term worries about the site:–

“…the Head of the West Java Energy and Mineral Resources Office, Bambang Tirto Mulyono, stated that the incident was caused by a faulty mining method carried out by the mine management. Warnings have been conveyed many times by the Energy and Mineral Resources department, and even preventive measures have been taken by the police.”

“We have repeatedly warned the mining authorities, even in a loud tone. The Cirebon Police have also installed a police line at the location since February because the mining methods carried out are not in accordance with safety standards. Mining should have been done from above, not from below,” said Bambang when met at the scene.“

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

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:-

https://bsky.app/profile/subfossilguy.bsky.social/post/3lqaup44u6k2l

And second is Jan Beutel, who is new to Bluesky (a well timed introduction, sir!), who has posted this before and after comparison that is simply awesome:-

Birchgletscher collapse, before and after.

— Jan Beutel (@janbeutel.bsky.social) 2025-05-28T15:29:58.028Z

These two scientists will be really good sources of information over the coming days. Reuters also has a nice summary news video of the events:-

So, was the final collapse my scenario 1 (a further failure of Kleine Nesthorn that triggered failure of the Birch Glacier) or scenario 2 (a catastrophic failure of the glacier itself)? At this stage, I am not sure. The seismic data will reveal all in due course – this event will have been extremely well captured in this dataset. Jan Beutel posted seismic record soon after the failure – look at the scale of the signal that the landslide generated:-

What an inaugural post on bsky.app. A (the) major glacier collapse at Bichgletscher/Kleines Nesthorn.

— Jan Beutel (@janbeutel.bsky.social) 2025-05-28T13:43:41.174Z

I am certainly no expert in analysing this data, so I can only speculate, but it is interesting that there was an elevated signal in the two minutes or so before the catastrophic failure began. What was this? Was movement starting to occur in the Birch Glacier, or was there an event on the slope above (or am I misreading the signal)?

So, for now, attention will focus on three things:

First, the valley of the Lonza river is dammed and a substantial lake is starting to develop. This has the potential to inundate the remaining properties in Blatten and, of course, to release a major flood. Two further communities downstream have been evacuated. There is a good Youtube video of this situation:

This will need to be addressed with urgency, but Switzerland is well placed in terms of expertise and resource to mitigate the threat.

Second, attention will need to be paid to the Birch Glacier and the slopes on the Kleine Nesthorn. Is there the potential for a further failure? Massive though this collapse has been, it is unlikely to have included all of the mass on the slope. What is the state of the remaining material? This will be a critical question in terms of the safety of those charged with managing the flood hazard.

And finally, many people have lost their homes, and more may do so in the coming days. This is a devastating event for them, and they will need considerable help.

As a final comment, I have to pay tribute to those individuals who have managed this hazard. The situation was immensely unpredictable, but they acted quickly and decisively. Whilst it is a tragedy that someone is missing, their actions saved many lives.

In due course, I’m sure that there will be a series of papers about this remarkable event. There are many lessons to be learnt from an absolutely amazing case study. As always, please remember that my posts here are provisional and speculative – the definitive analyses comes from the on site experts and from rigorous scientific study in due course.

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
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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.