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The atmosphere's growing thirst is making droughts worse, even where it rains

Phys.org: Earth science - Wed, 06/04/2025 - 15:23
Hot air holds more moisture. That's why you can blow your hair dry even after a steamy shower. It's also what dumps rain in the tropics and sucks water from desert soils.

Study details processes that keep pollutants aloft despite a drop in emissions

Phys.org: Earth science - Wed, 06/04/2025 - 15:19
Nitrates in the atmosphere reduce air quality and play an important role in climate change. An international team led by Hokkaido University researchers has revealed how chemical processes in the atmosphere have led to persistently high nitrate levels despite a reduction in emissions over the past few decades.

Scientists reveal what drove 2023's record-smashing North Atlantic marine heat wave

Phys.org: Earth science - Wed, 06/04/2025 - 15:00
In a UNSW-led Nature study, researchers say that an off-the-scale marine heat wave in the North Atlantic Ocean in 2023 was caused by record-breaking weak winds combined with increased solar radiation—all on the back of ongoing climate change.

Racing to save NJ island before it's swallowed by rising seas

Phys.org: Earth science - Wed, 06/04/2025 - 14:25
Lenore Tedesco doesn't need to venture far to witness sea-level rise. She tracks its relentless advance from her window at work.

Study projects that increasing wildfires in Canada and Siberia will actually slow global warming

Phys.org: Earth science - Wed, 06/04/2025 - 13:59
Even if you live far from the boreal forests in Canada and Siberia, you've likely noticed an increase in smoke from their forest fires. During major blazes in 2023, the smoke tinted the New York sky orange and drifted as far south as New Orleans. These blazes have surged in the last decade due to the effects of climate change—warmer summers, less snow cover in the spring, and the loss of sea ice. Experts expect that trend to continue.

Biofilm distribution helps pinpoint areas where microplastics will accumulate

Phys.org: Earth science - Wed, 06/04/2025 - 13:31
The accumulation of microplastics in the environment, and within our bodies, is an increasingly worrisome issue. But predicting where these ubiquitous particles will accumulate, and therefore where remediation efforts should be focused, has been difficult because of the many factors that contribute to their dispersal and deposition.

High Relief, Low Relief — Glaciers Do It All

EOS - Wed, 06/04/2025 - 13:27
Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: AGU Advances

Mountain landscapes are as much a product of erosion as they are of uplift. It is certainly true that glaciers can carve uplifted regions, increasing their topographic relief.

Using numerical modeling that integrates both river and glacial erosion across a time span that includes glacial-interglacial cycles, Bernard et al. [2025] flip the script on how we think glaciers shape mountains. The authors show that a “glacial sheltering” effect can lead to the development of extensive low-relief surfaces at moderate elevations, and they review the existence of candidate surfaces in Scandinavia and other locations.

A key finding is that such surfaces can not only be preserved by glaciation, but they can also emerge from it, and at variable elevations that are a function of ice volume. This is significant not just because humans are inspired by mountains and their topography: flat or low-relief surfaces play a large role as a reference elevation in explaining landscape evolution and in tectonic studies of uplift that make assumptions about where, when, and how such surfaces originated.

Citation: Bernard, M., van der Beek, P. A., Pedersen, V. K., & Colleps, C. (2025). Production and preservation of elevated low-relief surfaces in mountainous landscapes by Pliocene-Quaternary glaciations. AGU Advances, 6, e2024AV001610.  https://doi.org/10.1029/2024AV001610

—Peter Zeitler, Editor, AGU Advances

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.

Former Department of Energy Leader Reflects on a Changing Landscape

EOS - Wed, 06/04/2025 - 12:51
Source: AGU Advances

Shortly after President Joe Biden took office in 2021, he nominated Asmeret Asefaw Berhe, then a biogeochemist at the University of California, Merced, to oversee the Department of Energy’s (DOE) Office of Science. After a 15-month vetting process involving interviews, a mountain of paperwork, and, ultimately, a Senate confirmation, the AGU medalist became the first person of color and the first Earth scientist to hold the position. She served in the position for just under 2 years.

Now, with science and diversity programs under attack, she reflects on her path to leadership in a new commentary in AGU Advances. Berhe became familiar with DOE’s science program as a graduate student at the University of California, Berkeley. She later went on to receive DOE funding, collaborate with researchers from various national laboratories, and mentor scientists who went on to secure DOE positions. She says that combined with guidance from her mentors, these experiences helped her develop the skills she needed for her DOE appointment, not only in science but in managing, accounting, mediation, and ethical guidance.

Berhe, who was born in Eritrea and was one of only a few undergraduate women at Asmara University studying soil science, prioritized basic research, robust science communication, and promoting diversity in STEM (science, technology, engineering, and mathematics) in her DOE role. Providing opportunities in STEM for people from all walks of life starts with equalizing the distribution of funding, she writes. She cited an American Physical Society report that found, in 2018, 90% of federal research funding went to the top 22% of institutions, even though the vast majority of students—especially those from low-income backgrounds—attend other schools. Under Berhe’s tenure, the DOE began asking grant applicants to demonstrate plans for collaborating with schools less likely to receive funding, enabling scholars from diverse backgrounds to access DOE resources.

Berhe thinks recent efforts by some politicians to end diversity, equity, and inclusion (DEI) programs are partly because of a misconception around what DEI means. These programs are often misconstrued as serving only gender or racial minorities from urban environments, when, in fact, many are intended to serve a much wider range of Americans, she writes.

Today’s political climate sometimes leaves Berhe with feelings of despair. But she remains hopeful that with time, the next generation of scientists will benefit from opportunities like those she’s had. “Together, we will weather this storm,” she writes. (AGU Advances, https://doi.org/10.1029/2025AV001757, 2025)

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

Citation: Sidik, S. M. (2025), Former Department of Energy leader reflects on a changing landscape, Eos, 106, https://doi.org/10.1029/2025EO250211. Published on 4 June 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.

Thicker sediments under Salt Lake could result in more intense ground shaking

Phys.org: Earth science - Wed, 06/04/2025 - 11:11
The sediments underlying the Salt Lake Valley are thicker in places than previously thought, indicating that current seismic hazard models likely underestimate the amount of shaking Utah's population center could experience in future earthquakes, according to new research led by University of Utah seismologists.

Generation and transport of fast electrons under a nonuniform magnetic field produced by a coil target

Physical Review E (Plasma physics) - Wed, 06/04/2025 - 10:00

Author(s): Zhi-Wei Wang, Tie-Huai Zhang, and Wei-Min Wang

We investigate with particle-in-cell simulation the transport of fast electrons of MeV under a kT-level magnetic field produced by a circular coil target, where the fast electrons are generated by a picosecond laser pulse with typical intensity of 5×1019W/cm2 adopted in fast ignition. The fast elect…


[Phys. Rev. E 111, 065204] Published Wed Jun 04, 2025

Ban high-seas fishing, mining 'forever': Experts

Phys.org: Earth science - Wed, 06/04/2025 - 09:00
Governments should ban all mining and fishing in the high seas "forever" to protect ocean biodiversity, climate stability—and humanity, climate and ocean experts said Wednesday.

The 1 June 2025 landslide at Muta township in Tibet

EOS - Wed, 06/04/2025 - 06:09
What’s Next for Science?

A 200,000 cubic metre rockslide in a remote area of Tibet on Sunday has left ten people dead or missing.

On 1 June 2025 a large rockslide occurred in Muta township in Chamdo (Qamdo) metropolitan area in Tibet. Note that Chinese media sources call this area Xizang Autonomous Region, but it is what most of us know as Tibet. Chinese media reports, which can be unreliable from Tibet, indicate that three people are confirmed to have been killed with a further seven reported to be missing. Two people were injured.

CGTN has a video online showing the landslide, which includes drone footage. The area has a dusting of snow, which makes interpretation difficult. CCTV also has the same footage posted to Youtube:-

This video includes imagery of the head scarp of the landslide:-

The head scarp of the 1 June 2025 rockslide at Muta in Tibet. Image from a video posted to Youtube by CCTV.

There is also a good image of the full length of the rockslide:-

The full extent of the 1 June 2025 rockslide at Muta in Tibet. Image from a video posted to Youtube by CCTV.

This landslide has a slightly unusual morphology, with much of the material from the upper portion of the slope stalled on the hillside. However, the mass of material in the valley floor is large, as this image shows:-

The lower portion of the 1 June 2025 rockslide at Muta in Tibet. Image from a video posted to Youtube by CCTV.

The landslide has blocked the valley and a small lake has started to develop. This will need to be managed. Note the run up of the landslide deposit on the opposite slope, which indicates that the mass was moving comparatively quickly. There are two people on the left of the image for scale.

The CGTN video suggests that the landslide was about 200,000 m3, which would be around 500,000 tonnes.

The precise location of this event is unclear to me. Chamdo is a large area centred on [31.1362, 97.2359]. A report by Xinhua suggests that the landslide occurred in Dengqen County (Dêngqên County), which is in the northwest of Chamdo, centred on [31.5396, 95.4156]. Wikidata indicates that Muta is located at [32.30957, 95.09376], and Google maps has this location as “Mutaxiang”, with “Muta town” a little to the west, so this is credible. We shall have to wait for a clear day to obtain satellite imagery to confirm this – given the limited loss of life, the landslide has probably not struck Muta itself.

As usual for China, especially when it comes to Tibet, the media footage includes lots of images of the response of the authorities to the disaster. Sadly, the likelihood of the missing people being recovered alive is very low.

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
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Imaging the seismic structure of the western Makran Subduction Zone

Geophysical Journal International - Wed, 06/04/2025 - 00:00
SummaryWe analyze data from 48 seismic stations located in the western part of the Makran Subduction Zone to gain a detailed knowledge of the crustal and uppermost mantle structure in that region. The Makran is a flat subduction zone with a very thick accretionary wedge. It is a major tsunami hazard of the Indian Ocean but remains one of the world's least studied subduction zones. Its structure and evolution is increasingly becoming a subject of research interest as it can help to better understand the dynamics of flat subduction zones. Our P- and S-wave receiver function analyses reveal that the Arabian oceanic plate is currently dipping north-ward beneath the onshore accretionary wedge at a very low angle of 3°. The depth of the oceanic Moho in the coastal region is ∼30 km due to the presence of ∼22-24 km of sedimentary cover. It increases to ∼60 km beneath the Jazmurian Depression and further deepens to ∼80 km beneath the Bazman and Taftan volcanoes. The change from a relatively flat to a steeper subduction occurs just south of the Qasr-e Qand thrust fault. From the combined results of the receiver function stacking and joint inversion of P-wave receiver functions and Rayleigh wave group dispersion data, we infer that the continental Moho varies within a depth range of 40 to 56 km, with the shallowest part beneath the Sistan Suture Zone and the deepest beneath the Taftan volcano. Based on shear-wave velocity models, the sedimentary cover thickness in the onshore accretionary wedge varies from Coastal Makran to 34 km in Inner Makran. The lower-than-normal mantle wedge shear-wave velocities suggest that the mantle wedge might have undergone at least 25 per cent serpentinization. From the velocity models we conclude that the crust of the Jazmurian Depression is more likely of continental origin.

Impact of geodetic information, subduction zone segmentation, and slow-slip events in probabilistic seismic hazard: A case study for Costa Rica

Geophysical Journal International - Wed, 06/04/2025 - 00:00
AbstractA Slow-Slip Event (SSE) is a slow release of tectonic stress along a fault zone, over periods ranging from hours to months. SSEs have been recorded in most of the geodetically well-instrumented subduction zones. Although these transient events observed by geodesy are typically excluded from probabilistic seismic hazard analysis (PSHA), they might play a crucial role in the seismic cycle by reducing the seismic slip rate (slip rate discounting the aseismic process). This effective reduction implies that incorporating SSEs into PSHA may improve the reliability of hazard assessments. Costa Rica, located at the southern end of the Middle American Trench, hosts large earthquakes as well as SSEs. Shallow and deep SSEs have long been detected at the Nicoya peninsula, in northern Costa Rica, and recently, also in the southern part of the country at the Osa peninsula. In this study, we first collect geodetic and SSE observations in Costa Rica. Then, we propose a method to incorporate them into PSHA, based on identifying regions where SSEs occur, inferring slip deficits and estimating seismic slip rates in each subduction segment. Next, we analyze the implications for PSHA and its epistemic uncertainty, using these seismic slip rates, the resulting seismic moment rate budgets, and determining earthquake rates and maximum magnitudes with different approaches. Finally, we compute a countrywide PSHA following the 2022 Costa Rica Seismic Hazard Model (CRSHM 2022) but modifying the seismic source characterization using geodetic information for the regions where SSEs occur. Compared to the CRSHM 2022, this approach leads to reductions of the resulting peak ground acceleration at return period of 475 years (PGA-475) of up to ∼15 per cent in the Nicoya peninsula, but also to an increase up to ∼40 per cent in the Central Pacific region and ∼30 per cent in the Osa peninsula. Moreover, we find that, under a geodetic-based approach and disregarding SSEs, the PGA-475 would increase by up to ∼10 per cent. Our novel approach underscores the relevance of incorporating geodetic observations and particularly SSEs into PSHA, especially in subduction margins near the coast.

Five geoengineering trials the UK is funding to combat global warming

Phys.org: Earth science - Tue, 06/03/2025 - 16:22
The UK government recently announced plans to fund five small-scale trials related to geoengineering. It's the first time a state research funding body has put serious money into what's known as solar radiation management, or SRM, which seeks to cool the planet by reflecting more of the sun's energy back into space.

Scientists say next few years vital to securing the future of the West Antarctic Ice Sheet

Phys.org: Earth science - Tue, 06/03/2025 - 15:12
Collapse of the West Antarctic Ice Sheet could be triggered by very little ocean warming above present-day, leading to a devastating four meters of global sea level rise to play out over hundreds of years, according to a study now published in Communications Earth & Environment, co-authored by the Potsdam Institute for Climate Impact Research (PIK). However, the authors emphasize that immediate actions to reduce emissions could still avoid a catastrophic outcome.

What made Mount Etna's latest eruption so rare

Phys.org: Earth science - Tue, 06/03/2025 - 15:10
Mount Etna, the volcano that towers over eastern Sicily, has again captivated the world with a spectacular show, spewing smoke and high into the sky.

Simulation shows how declines in coral reef calcification could affect future ocean carbon sink capabilities

Phys.org: Earth science - Tue, 06/03/2025 - 14:46
A team of meteorologists, Earth scientists and oceanographers at Sorbonne Université, working with one colleague from Université Paris-Saclay and another from Université Brest, all in France, has developed a simulation that they believe shows how declining coral reef calcification could slow global warming.

Is Your Shampoo Washing Up in Antarctica?

EOS - Tue, 06/03/2025 - 13:36

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.

Los ríos de Brasil se están infiltrando

EOS - Tue, 06/03/2025 - 13:30

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.

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