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Observation-informed deep learning cuts ENSO projection uncertainty

Phys.org: Earth science - Thu, 09/04/2025 - 16:02
El Niño-Southern Oscillation (ENSO) is the strongest interannual variability signal in Earth's climate system. The shifts between its warm and cold phases profoundly impact global extreme weather, ecosystems, and economic development. However, current climate models show large discrepancies in their future projections of ENSO sea surface temperature (SST) variability.

Radar Surveys Reveal Permafrost Recovery After Wildfires

EOS - Thu, 09/04/2025 - 14:31
Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: AGU Advances

Permafrost is considered a critical global component of the cryosphere given its climate-sensitive nature and its key geomorphological and ecosystem role. Permafrost is also affected by wildfires which may cause the crossing of a tipping point in cryospheric systems. In fact, wildfires may reduce vegetation, destroy organic layers, modify surface albedo, leading to active layer thickening and ground subsidence. Permafrost itself is subjected to long term deformation after wildfires, but this deformation is currently poorly understood.

Cao and Furuya [2025] use remote sensing to explore ground surface deformation signals across multiple fire scars in the past five decades in North Yukon. The authors find that post-permafrost evolution follows three distinct phases characterized by land subsidence soon after the event and final recovery of the permafrost over a 50-year timescale, which implies soil uplift. Such an uplift phase is rarely reported and is related to vegetation regeneration and soil greening after the fire. These provide thermal protection, suggesting a critical mechanism of permafrost recovery. These findings highlight the resilience of boreal-permafrost systems against wildfires, but continuous monitoring is needed as wildfire and climate change intensify.

Citation: Cao, Z., & Furuya, M. (2025). Decades-long evolution of post-fire permafrost deformation detected by InSAR: Insights from chronosequence in North Yukon. AGU Advances, 6, e2025AV001849. https://doi.org/10.1029/2025AV001849

—Alberto Montanari, Editor-in-Chief, 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.

An Accessible Alternative for Undergraduate Research Experiences

EOS - Thu, 09/04/2025 - 13:33

Undergraduate research experiences (UREs) in science, technology, engineering, and mathematics (STEM) offer students hands-on research experience and essential professional skills and connections to prepare them to succeed in the workforce. They also cultivate students’ sense of belonging, confidence, and identity—and promote retention—in STEM fields [National Academies of Sciences, Engineering, and Medicine, 2017; Rodenbusch et al., 2016].

To be effective, UREs should be thoughtfully designed to meet the needs of students who may otherwise miss out on career opportunities tied to networking and community-building through such programs. Existing URE programs have followed a range of approaches, but traditionally, many have been centered around short-duration, time-intensive, individual, mentor-directed experiences, such as full-time summer internships in field or laboratory settings. However, these traits can inadvertently exclude some student populations, a concern that is leading many programs to modify their structure and design to engage broader groups.

To lower barriers to participation in UREs, we developed the Authentic Research through Collaborative Learning (ARC-Learn) program at Oregon State University (OSU). ARC-Learn, which ran from 2021 to 2024 and comprised two overlapping student cohorts, offered a long-term, low-intensity program focused on Arctic science and inclusive mentorship. It was designed to help students engage in a science community, foster identities as STEM professionals, and develop critical scientific and data literacy skills and 21st century competencies such as teamwork and communication.

Table 1. Design Features of ARC-LearnFeatureDescriptionDuration18 months (2 academic years)Intensity2–4 hours per weekLocationOn campus or remoteMentorshipMultiple mentors working in teams with multiple studentsTopic selectionStudent drivenStudent supportMentors, peers, program administrators, academic advisorsMentorship developmentInclusive mentorship training, facilitated peer learning communityResearch tasksDevelop research question, find data and analyze data, draw conclusions, and present findingsStudent developmentDiscover own strengths as researchers, work with a team, supplemental training in missing skills

ARC-Learn incorporated alternative design features (Table 1) to meet the needs of students who do not typically have access to time-intensive field or lab-based UREs, such as transfer students, remote students, and those with dependent care, military service, and other work commitments [Scott et al., 2019] or who have nontraditional enrollment patterns (e.g., dual enrollment in both university and community college, varying enrollment from term to term).

The program was framed in the context of Arctic science because of the region’s outsize effects on climate, ecosystems, and communities globally and to engage students with long-term research investments in polar regions [Marrongelle and Easterling, 2019]. The Arctic also offers a dynamic and interdisciplinary context for a URE program, enabling students to follow their interests in investigating complex science questions. In addition, numerous long-term Arctic monitoring programs offer rich datasets useful in all kinds of STEM careers.

Despite encountering challenges, the ARC-Learn model proved successful at engaging and motivating students and also adaptive as program organizers made adjustments from one cohort to the next in response to participant feedback.

The ARC-Learn Model

With support from mentors and peers, students experienced the whole research arc and gradually took ownership of their work.

Each ARC-Learn cohort lasted 2 academic years and included a dozen or more students. Participants received a stipend to offset costs associated with participation, such as childcare and missed work time, and had the option of obtaining a course credit each term to meet experiential learning requirements. With support from mentors and peers, they experienced the whole research arc and gradually took ownership of their work through three key phases of the program.

Early year 1: Build research teams. Some URE mentorship models involve a mentor primarily driving selection of a research topic and the student completing the work. In ARC-Learn, students learned from multiple mentors and peers, while mentors supported each other and received feedback from students (Figure 1). The students self-selected into research teams focused on a broad topic (e.g., marine heat waves or primary productivity), then developed individual research questions based on their strengths and interests.

Fig. 1. Some models of undergraduate research experiences have involved a mostly one-way transfer of knowledge from a single mentor to a single student, with the mentor deciding the research topic and the student completing the work. In ARC-Learn, students learned from multiple mentors and peers as part of small-group research teams, while mentors supported each other and received feedback from students.

Mentor-student teams met every other week—and students met one-on-one with mentors as needed—to support individual projects. The entire cohort also met twice a month to discuss topics including the fundamentals of Arctic science and the scientific process and to report out on progress toward milestones.

Late year 1 to middle of year 2: Develop research questions and find and analyze data. With no field or lab component to the program, ARC-Learn students worked exclusively with existing data. These data came from NASA and NOAA satellite-based sources such as the Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Very High Resolution Radiometer, and Soil Moisture Active Passive (SMAP) instruments; shipboard sources such as NOAA’s Distributed Biological Observatory, the Alaska Ocean Observing System, and the University-National Oceanographic Laboratory System’s Rolling Deck to Repository; and the National Science Foundation’s (NSF) Arctic Data Center and NOAA’s National Centers for Environmental Information.

Students often revised their research questions or the datasets they used multiple times to produce meaningful findings (Figure 2). Notably, access to these datasets proved critical to the educational experience of ARC-Learn students, highlighting the importance of maintaining them in public archives for future URE activities.

Fig. 2. ARC-Learn students developed their own research questions and worked exclusively with existing data to answer them. Students often revised their research questions or datasets multiple times to produce meaningful findings.

Many students struggled with finding, cleaning, analyzing, and interpreting data, often because of limited experience with tools such as geographic information system software and programming languages such as Python and R. At times, the required expertise was beyond even their mentors’ knowledge. Hands-on skill development workshops during cohort meetings connected students with additional mentors proficient in specific platforms and tools to help fill knowledge gaps and help students overcome obstacles.

Although the students encountered occasional setbacks, they reported that achievements such as settling on a final research question and creating rich data visualizations proved deeply rewarding and motivated further progress.

Late year 2: Share the results. Over several months, students created research posters with feedback and support along the way from their teammates, mentors, and the entire cohort. The program concluded with a grand finale, featuring on-campus gatherings for remote and in-person students, a dress rehearsal poster session, a celebratory dinner, and final presentations at a university-wide undergraduate research symposium.

Zoe’s Story

After a successful 7-year military career, Zoe enrolled at OSU to study the Arctic through her participation in ARC-Learn. As a student in cohort 2, she experienced several challenges along the research arc before finding success, and her experience helps illustrate the program’s model.

Zoe joined fellow students and mentors in the Marine Heatwaves research team and then narrowed her focus by exploring scientific literature and talking with her primary mentor to understand physical and chemical factors associated with marine heat waves as well as their effects on ocean ecosystems. She developed several research questions focused on how factors such as atmospheric pressure and temperature have affected the development and extent of marine heat waves off Alaska since 2010.

As Zoe and her mentor considered available datasets and relevant literature further, they realized that her questions were still too broad given the number of variables affecting ocean-atmosphere interactions. At one of the full-cohort meetings, she shared her difficulties and frustrations, prompting another mentor to offer their help. This mentor worked with Zoe to understand a key meteorological feature—the Aleutian Low—in the area she was studying, as well as relevant data available through the European Union’s Copernicus Climate Change Service [Hersbach et al., 2023] and the appropriate analysis platform.

“We jumped in and learned it together. She helped me find the right data, which in turn, allowed me to finalize my research question,” Zoe said.

Nuanced and iterative feedback from mentors and peers guided ARC-Learn participants, including Zoe, to design posters that balanced visual presentations of data alongside descriptive text to explain research findings. Credit: Ryan Brown

From that point, Zoe quickly landed on a focused question that she could address: Does a disruption in the Aleutian Low lead to marine heat waves over the North Pacific region? The final step was to develop a visually striking poster to invite attention, questions, and ideas during the research symposium.

“Seeing other people interested in my research…was validating of me as a scientist.”

Zoe’s experience at the poster session captured what we heard from many other students in the program. Even after her 2 years of being immersed in her project and working with mentors and peers, she said she felt imposter syndrome as a student trying to become a scientist and thought no one would care about her research.

“But people were really interested,” she said. “Seeing other people interested in my research, able to read and understand it on a poster, [and] ask me questions and suggest ideas was validating of me as a scientist.”

A Responsive Approach to URE Design

Through ARC-Learn, program leads sought to expand knowledge about the benefits and challenges of a long-duration, lower-intensity, team-based URE model. Because it was a design-based research program, mentor, student, and coordinator feedback was collected and continually used to make program adjustments [Preston et al., 2022, 2024].

Feedback was collected through pre-, mid-, and end-of-program surveys, as well as pre- and end-of-program interviews, and analyzed by a research and evaluation team. Findings were reported to the program leads, who also met regularly with external expert advisers to get additional recommendations for adjustments. By running two overlapping cohorts (the second started when the first was halfway completed), organizers could address issues that arose for the first cohort to improve the experience of the second one.

Lessons from ARC-Learn are documented in a practitioner guidebook, which discusses practical considerations for others interested in implementing alternative URE models [Brown et al., 2024]. In the guidebook, we examine each design component of ARC-Learn and offer recommendations for designing UREs that meet enrolled students’ specific learning needs and develop their science skills to meet relevant workforce demands.

Novel elements of the Authentic Research through Collaborative Learning (ARC-Learn) program were important in influencing participants’ persistence and success.

A few valuable lessons learned include the following.

Attrition. Expect high attrition rates in UREs designed for nontraditional students, and do not react by making drastic program changes that risk sacrificing otherwise successful program elements. We observed a 45% attrition rate in each cohort, which is indeed high but perhaps not surprising considering the population involved in the program—largely transfer students and those with caregiving or work responsibilities.

Most participants who left did so because of life crises or obligations that paused their research and educational goals. This observation embodies the complexity of students’ lives and reinforces the need for continually creative, flexible, inclusive program structures. For those who completed ARC-Learn, novel elements of the program (e.g., working in teams) were important in influencing their persistence and success.

Remote research applications. The first cohort started in 2021 entirely via remote instruction during the COVID-19 pandemic, before eventually transitioning to a hybrid approach as in-person instruction resumed. All ARC-Learn students in cohort 1 returned to campus, except one Ecampus student, who remained online. The program team and mentors struggled to balance the needs of the remote student, who eventually became somewhat detached from their research team.

As teamwork, camaraderie, and inclusivity are important qualities of the program, we decided for cohort 2 to recruit enough Ecampus students (plus two dedicated mentors) to form a research team of their own. The remote team was engaged and productive—meeting deadlines and producing high-quality work—highlighting the potential of all-remote URE models for students who might otherwise lack access to meaningful research opportunities.

Student-driven research. ARC-Learn empowered students to pursue their own research questions, fostering their autonomy and ownership of their work. However, the open-endedness of selecting their own research paths and the lack of guardrails proved challenging for participants.

We thus hired a program coordinator to provide one-on-one logistical support; establish clear expectations, timelines, and scaffolded assignments; and arrange workshops to teach programming and data analysis skills. This approach, as reported by students who worked with the coordinator, helped many program participants stay on track and ultimately complete their research project.

Mentor coordination. Enabling student success also meant supporting mentors. Organizers provided inclusive mentorship trainings and facilitated a peer learning community. They also made programmatic adjustments in response to experiences in the first cohort.

The student-driven nature of the research sometimes resulted in mismatches between student interests and mentor expertise in cohort 1. So in cohort 2, we engaged mentors earlier in the planning process to define thematic areas for the research teams, creating topics broad enough for students to find an area of interest but narrow enough for mentors to provide guidance. In addition, many mentors had field schedules typical of polar scientists, often resulting in weeks to months at sea. We purposefully paired mentors and asked about planned absences so we could fill any gaps with additional support.

Overall, students in cohort 2 reported feeling highly supported and valued by their mentors and that mentors created welcoming environments to ask questions and solve problems together.

A Foundation to Build On

Participants gained a deep understanding of the complexities and challenges of modern science as well as knowledge and skills needed in scientific education and careers.

From students’ feedback—and the research they did—it’s clear that participants who completed the ARC-Learn program gained a deep understanding of the complexities and challenges of modern science as well as knowledge and skills needed in scientific education and careers. The program thus highlights paths and lessons for others looking to develop successful alternatives to traditional UREs.

Many former ARC-Learn students are continuing to develop research skills, particularly in polar science, through internships and employment in field and lab research efforts. Zoe is working toward a bachelor’s degree in environmental sciences and exploring interests in environmental hazards, conservation, and restoration. For her, the program served as a foundation from which she is building a career and establishing confidence in herself as a scientist.

“I thought I’d have to play catch-up the whole time as an older, nontraditional student,” she said. But through the experience, “I realized I could start anywhere.”

Acknowledgments

ARC-Learn was a collaboration between OSU’s College of Earth, Ocean and Atmospheric Sciences and STEM Research Center. This work is supported by the U.S. NSF (award 2110854). Opinions, findings, conclusions, and recommendations in these materials are those of the authors and do not necessarily reflect the views of NSF.

References

Brown, R., et al. (2024), ARC-Learn Practitioner Guidebook: Practical considerations for implementing an alternative model of undergraduate research experience, Ore. State Univ., Corvallis, https://doi.org/10.5399/osu/1177.

Hersbach, H., et al. (2023), ERA5 monthly averaged data on single levels from 1940 to present, Copernicus Clim. Change Serv. Clim. Data Store, https://doi.org/10.24381/cds.f17050d7.

Marrongelle, K., and W. E. Easterling (2019), Support for engaging students and the public in polar research, Dear Colleague Letter prepared for the U.S. National Science Foundation, Alexandria, Va., www.nsf.gov/funding/opportunities/dcl-support-engaging-students-public-polar-research/nsf19-086.

National Academies of Sciences, Engineering, and Medicine (2017), Undergraduate Research Experiences for STEM Students: Successes, Challenges, and Opportunities, 278 pp., Natl. Acad. Press, Washington, D.C., https://doi.org/10.17226/24622.

Preston, K., J. Risien, and K. B. O’Connell (2022), Authentic Research through Collaborative Learning (ARC-Learn): Undergraduate research experiences in data rich Arctic science formative evaluation report, STEM Res. Cent., Ore. State Univ., Corvallis, https://doi.org/10.5399/osu/1156.

Preston, K., J. Risien, and N. Staus (2024), Authentic Research through Collaborative Learning (ARC-Learn): Undergraduate research experiences in data rich science summative evaluation report, STEM Res. Cent., Ore. State Univ., Corvallis, https://doi.org/10.5399/osu/1178.

Rodenbusch, S. E., et al. (2016), Early engagement in course-based research increases graduation rates and completion of science, engineering, and mathematics degrees, CBE Life Sci. Educ., 15(2), ar20, https://doi.org/10.1187/cbe.16-03-0117.

Scott, G. W., S. Humphries, and D. C. Henri (2019), Expectation, motivation, engagement and ownership: Using student reflections in the conative and affective domains to enhance residential field courses, J. Geogr. Higher Educ., 43(3), 280–298, https://doi.org/10.1080/03098265.2019.1608516.

Author Information

Ryan Brown (ryan.brown@oregonstate.edu), Laurie Juranek, and Miguel Goñi, College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis; and Julie Risien and Kimberley Preston, STEM Research Center, Oregon State University, Corvallis

Citation: Brown, R., L. Juranek, M. Goñi, J. Risien, and K. Preston (2025), An accessible alternative for undergraduate research experiences, Eos, 106, https://doi.org/10.1029/2025EO250326. Published on 4 September 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.

New method to pinpoint soil erosion could help protect waterways

Phys.org: Earth science - Thu, 09/04/2025 - 13:31
Cranfield University experts have developed a new method to precisely identify soil erosion hotspots along waterways, allowing for preemptive mitigation measures to be put in place that protect land and water systems.

The hidden chemistry of Earth's core is revealed by how it froze

Phys.org: Earth science - Thu, 09/04/2025 - 09:00
A study by researchers at the University of Oxford, University of Leeds, and University College London has identified a new constraint on the chemistry of Earth's core, by showing how it was able to crystallize millions of years ago. The study is published in Nature Communications.

Estimation of Water Heat Flux in Small Reservoirs: The Role of Neural Networks and Regression Techniques

Publication date: Available online 22 August 2025

Source: Advances in Space Research

Author(s): Amir Rezazadeh, Pooria Akbarzadeh, Milad Aminzadeh, Iman Zabbah, Mostafa Dolatimahtaj, Mohammad Ali Jafari

Very high energy proton acceleration in Vela-type pulsar wind nebulae

Publication date: Available online 22 August 2025

Source: Advances in Space Research

Author(s): A.M. Bykov, A.N. Fursov, K.P. Levenfish, A.E. Petrov

Numerical and Experimental Analysis of an Origami Based Deployable SRR-FSS for UWB-SATCOM Applications

Publication date: Available online 22 August 2025

Source: Advances in Space Research

Author(s): Vedat ÖZKANER, Fatih Özkan ALKURT, Olcay ALTINTAŞ, Emine Ceren GÖZEK, Muharrem KARAASLAN

Spacecraft Surveys Shed New Light on Auroral Kilometric Radiation

EOS - Wed, 09/03/2025 - 18:53
Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: AGU Advances

Auroral Kilometric Radiation (AKR) is a type of radio wave emitted from Earth’s auroral regions. It is the dominant radio emission from Earth and has been extensively studied, though previous analyses were constrained by limited spacecraft coverage.

Today, with the availability of more spacecraft observations, it is possible to improve our understanding of the Earth’s most intense natural radio emission. Thanks to these data, Wu et al. [2025]  find that Auroral Kilometric Radiation preferentially occurs at high-latitudes and on the Earth’s night-side. They also found that the dense plasmasphere, which is a region of high-density plasma around Earth, blocks AKR from traveling, thus forming an equatorial shadow zone around the plasmasphere. Furthermore, the authors discover that the low-density ducts within the plasmasphere act as waveguides, enabling AKR to penetrate the dense plasmasphere and propagate along these channels.

The findings provide valuable insights into Earth’s electromagnetic environments, space weather events and geomagnetic storms that may adversely affect satellites, communication systems, GPS, and power grids on Earth.  

Citation: Wu, S., Whiter, D. K., Zhang, S., Taubenschuss, U., Zarka, P., Fischer, G., et al. (2025). Spatial distribution and plasmaspheric ducting of auroral kilometric radiation revealed by Wind, Polar, and Arase. AGU Advances, 6, e2025AV001743. https://doi.org/10.1029/2025AV001743

—Alberto Montanari, Editor-in-Chief, 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.

Decades of data show African weather disturbances intensify during La Niña

Phys.org: Earth science - Wed, 09/03/2025 - 18:41
A recent study reveals how a major global climate pattern influences the African weather systems that help seed Atlantic hurricanes. The findings, published in the Journal of Climate, could lead to better seasonal forecasts of rainfall, drought, and tropical cyclone activity across the Atlantic basin.

The growing threat of vast ravines swallowing streets and homes

Phys.org: Earth science - Wed, 09/03/2025 - 18:10
Deep, gigantic cracks in the Earth known as gullies are tearing through African cities, swallowing up houses and streets, destroying infrastructure and displacing tens of thousands of people. Left unchecked, this new geological hazard could force millions of people to abandon their homes in the coming decades.

Soot's climate-altering properties change within hours of entering atmosphere

Phys.org: Earth science - Wed, 09/03/2025 - 17:25
Billions upon billions of soot particles enter Earth's atmosphere each second, totaling about 5.8 million metric tons a year—posing a climate-warming impact previously estimated at almost one-third that of carbon dioxide.

Earth system models' inaccurate gross primary productivity simulations threaten land carbon uptake estimates

Phys.org: Earth science - Wed, 09/03/2025 - 16:18
Terrestrial ecosystems, vital for absorbing atmospheric carbon dioxide to mitigate climate change, rely on Earth system models (ESMs) for estimating carbon uptake—a cornerstone of climate policy, carbon budgeting and land management strategies. Yet new research from the Chinese Academy of Sciences (CAS) reveals critical flaws in how these models represent a key metric of carbon absorption, raising concerns about the reliability of long-term climate projections.

Sensors reveal surprising drop in methane emissions after flooding in coastal wetlands

Phys.org: Earth science - Wed, 09/03/2025 - 16:03
University of Toledo environmental researchers trooped through the woods and wetlands of the Ottawa National Wildlife Refuge for a week in early June. Their mission? To outfit an approximately 16-acre site with nearly 300 sensors that will constantly monitor a slew of metrics related to the soil, water and plants, including the flow of sap through trees.

New modeling indicates 100-year-old geological theory on the Himalayas may have been wrong all along

Phys.org: Earth science - Wed, 09/03/2025 - 15:20
For the last century, Émile Argand's theory on the formation and geological support system of the massive Himalayan mountain range has remained the predominant explanation widely accepted among geologists. This theory states that the ongoing collision of the Indian and Asian continental plates forced the crusts of the two plates to double in thickness and that this ultra-thick crust alone holds up the region's mountains, which were formed from these colliding structures.

Safe underground carbon storage would only reduce warming by 0.7°C, analysis finds

Phys.org: Earth science - Wed, 09/03/2025 - 15:00
For the first time, a study maps safe areas that can practically be used for underground carbon storage, and estimates that using them all would only cut warming by 0.7°C. The result is almost ten times lower than previous estimates of around 6°C, which considered the total global potential for geological storage, including in risky zones, where storing carbon could trigger earthquakes and contaminate drinking water supplies. The researchers say the study shows that geological storage is a scarce, finite resource, and warn that countries must use it in a highly targeted way.

Desert soils can emit greenhouse gases in minutes—even without microbes

Phys.org: Earth science - Wed, 09/03/2025 - 14:28
A study from researchers at Ben-Gurion University of the Negev reveals that desert soils can emit powerful greenhouse gases within minutes of being wetted—even in the absence of microbial life.

'Major floods and droughts every 15 years': AI forecasts a crisis for Pakistan

Phys.org: Earth science - Wed, 09/03/2025 - 14:25
A new study led by Professor Jonghun Kam's team at POSTECH (Pohang University of Science and Technology) has uncovered a shocking forecast for Pakistan's future. Using a cutting-edge AI model, the research predicts that the country will face unprecedented "super floods" and "extreme droughts" on a periodic basis.

Bridging Old and New Gravity Data Adds 10 Years to Sea Level Record

EOS - Wed, 09/03/2025 - 13:38

As climate change accelerates, it’s more important than ever to understand the individual drivers of sea level rise, from land subsidence and coastal erosion to changes in ocean volume. For the past 20 years, scientists have had access to high-resolution, satellite-derived maps of Earth’s gravity field, which allows them to calculate fluctuations in global ocean mass.

Recently, geodesists have found a way to extend that record back 10 more years, significantly extending the time frame by which they can consistently measure global ocean mass change.

“This is the first observation-based global ocean mass time series” from 1993 to the present, said Jianli Chen, a geodesy researcher at Hong Kong Polytechnic University in China and a coauthor on the research.

By reconciling older and newer techniques for measuring ocean mass change, the team’s work improves calculations of long-term trends and provides a potential stopgap should satellite data no longer be available.

Shooting Lasers into Space

When scientists measure sea level rise, they consider two main components: how much the ocean’s volume has grown because of changes in water density—the steric component—and how much it has grown because it has gained mass from melted ice—the barystatic component.

Past estimates of total ocean mass change have relied on indirect methods like adding up mass loss from ice sheets, glaciers, and land water storage, explained Yufeng Nie, a geodesy researcher also at Hong Kong Polytechnic University and lead researcher on the new study. Mass lost from these areas is assumed to translate to an increase in ocean mass.

“But these individual estimates are not necessarily consistent, because they are developed by different groups” with different methodologies, Nie said.

In light of this, some researchers adapted satellite laser ranging (SLR), a technique in which scientists bounce ground-based lasers off orbiting satellites to track changes in ocean mass. SLR has been used for decades to measure Earth’s nonuniform gravity field by observing shifts in satellite orbits. A satellite’s altitude depends on Earth’s gravity at any given point, and gravity in turn depends on the distribution of mass beneath that point. Measuring satellite altitudes thus provides a window into measuring ocean mass changes.

“How can you observe, for example, ocean mass change from Antarctic melting using a technique with 4,000-kilometer spatial resolution?”

However, one key drawback to using SLR to measure barystatic sea level (BSL) change is that it can measure changes only on very large spatial scales, which limits its application in climate research, Chen said.

“How can you observe, for example, ocean mass change from Antarctic melting using a technique with 4,000-kilometer spatial resolution?” asked Chen.

Enter NASA’s Gravity Recovery and Climate Experiment (GRACE) missions. GRACE and its successor, GRACE Follow-On (GRACE-FO), each consisted of two satellites chasing each other along the same orbit, continuously sending laser beams back and forth. Like SLR, this process allowed the GRACE missions to provide maps of Earth’s surface mass, but at 10 times the resolution of SLR. And like with SLR, scientists have used GRACE gravity maps to track global ocean mass change.

But GRACE data, too, have their caveats. The first GRACE mission spanned 2002–2017, and GRACE-FO has spanned from 2018 to the present, a short time for understanding long-term trends. What’s more, the 11-month gap between GRACE and its successor meant that scientists were not able to calibrate the two satellites with each other, leaving some uncertainty about systematic differences between the missions.

A Near-Perfect Match

Nie, Chen, and their team were able to address both of these caveats by comparing SLR-based measurements of global ocean mass change with those from GRACE/-FO for the same time period, 2003–2022.

According to gravity maps provided by SLR, barystatic sea level change was 2.16 millimeters per year from 2003 to 2022, while GRACE/-FO measured 2.13 millimeters per year.

The new analysis shows that SLR and GRACE/-FO “agree quite well for the long-term trends,” Nie said. What’s more, researchers found no significant change in the calculation when the data transitioned from GRACE to GRACE-FO. “This gives us confidence that the SLR data, although it is of very low spatial resolution, can be used to tell us the ocean mass variations before 2002,” he added.

“Our SLR measurements…can provide a global constraint of the mass changes for the pre-GRACE era.”

The researchers were able to extend the time frame of their analysis back to 1993 by using SLR data, and they calculated a barystatic sea level change of 1.75 millimeters per year for 1993–2022. They attribute the lower rate of sea level rise in the past to recent acceleration of ice loss in Greenland.

“Our SLR measurements…can provide a global constraint of the mass changes for the pre-GRACE era,” Nie said.

This study was published in Proceedings of the National Academy of Sciences of the United States of America in June.

“Extending the record of measured BSL using satellite laser ranging back to 1993 is an important achievement,” said Bryant Loomis, chief of the Geodesy and Geophysics Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Md. “It allows the disaggregation of total sea level change, which is measured by altimetry, into its barystatic and steric components.”

“The long-term BSL estimate is also useful for assessing the accuracy of previous efforts to quantify the major land ice contributions to BSL prior to the launch of GRACE,” he added, referring to the method of adding together mass changes from glaciers, ice sheets, and land water storage. Loomis was not involved in the new research.

Nie, Chen, and their team are working to push the limits of SLR-derived barystatic sea level measurements to smaller spatial scales and lower uncertainties. They hope to demonstrate that SLR data can be used to measure mass change in Antarctica.

GRACE Continuity?

GRACE-FO launched in 2018 and is 7 years into its nominal 5-year mission. The satellites are in good health, and the nearly identical GRACE mission set a good precedent—it lived for more than 15 years. GRACE-FO might well overlap with its planned successor, GRACE-Continuity (GRACE-C), which is scheduled to launch in 2028.

The GRACE missions are designed to measure minute changes in Earth’s gravity at high spatial resolution. However, there was a coverage gap between the end of the GRACE mission and the start of GRACE-FO, and there may be a similar gap between GRACE-FO and GRACE-C. Credit: NASA/JPL-Caltech, Public Domain

However, recent woes for federally funded science in the United States have put GRACE-C’s future in doubt. Although NASA requested funding for GRACE-C for fiscal year 2026 through the mission’s launch, NASA’s acting administrator, Sean Duffy, recently stated his, and presumably President Donald Trump’s, desire to eliminate all Earth science at the agency (including healthy satellites). That cutback would likely nix GRACE-C.

In the near future, both Europe and China plan to launch satellite-to-satellite laser ranging missions that will provide GRACE-like measurements of Earth’s gravity, Chen said. However, the loss of GRACE-quality data would hamper climate scientists’ ability to accurately track drivers of sea level rise, he added. The SLR-derived measurements demonstrated in this recent research could help mitigate the loss, but only somewhat.

“There’s no way SLR can reach the same [resolution] as GRACE,” Chen said. “We can only use SLR to see the long-term, the largest scale, to fill the gap. But for many of GRACE’s applications—regional water storage or glacial mass change—no, there’s no way SLR can help.”

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

Citation: Cartier, K. M. S. (2025), Bridging old and new gravity data adds 10 years to sea level record, Eos, 106, https://doi.org/10.1029/2025EO250321. Published on 3 September 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.

Primera evaluación a nivel de especies revela riesgo de extinción en Mesoamérica

EOS - Wed, 09/03/2025 - 13:35

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

La reforestación es más compleja que simplemente plantar árboles. Esta incluye la evaluación de hábitats y ecosistemas, la identificación de la salud y la sostenibilidad de diferentes especies y el estudio de las estrategias para establecer nuevos asentamientos de árboles.

En regiones como Mesoamérica, donde los bosques están gravemente amenazados por las actividades humanas y el cambio climático, los conservacionistas interesados en la reforestación deben priorizar las especies cuyas poblaciones están disminuyendo. Para facilitar esta tarea, un grupo de investigadores evaluó el estado de conservación de las 4,046 especies de árboles endémicas de Mesoamérica, descritas en el proyecto Global Tree Assessment (Evaluación global de árboles). Es así como descubrieron que el 46% de estos árboles se encuentran en cierto riesgo de extinción.

Este estudio es el primero en evaluar el estado de todos los árboles endémicos en Mesoamérica.

El estudio, publicado en la revista Plants, People, Planet, es el primero en evaluar el estado de todos los árboles endémicos en Mesoamérica.

Emily Beech, autora principal del estudio y jefa de conservación en Botanic Gardens Conservation International (Conservación Internacional de Jardines Botánicos), enfatizó la importancia de enfocarse en esta región debido a sus altos niveles de biodiversidad, que con frecuencia están subrepresentados. Los países centroamericanos (Belice, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua y Panamá), dijo Beech, rara vez figuran entre los de mayor biodiversidad o como el hogar del mayor número de especies en peligro de extinción. Esta ausencia no se debe a una falta de biodiversidad, explicó, sino que es simplemente atribuible a su tamaño. El tamaño reducido de estos países hace que sean eclipsados por países grandes con bosques más extensos, como Brasil y la República Democrática del Congo. Pero, junto con México, Centroamérica alberga el 10% de la diversidad vegetal del mundo a pesar de representar menos del 1% de su superficie terrestre.

Para abordar esta brecha, los científicos primero identificaron árboles endémicos mesoamericanos a partir de evaluaciones presentadas en la Lista Roja de especies amenazadas de la Unión Internacional para la Conservación de la Naturaleza (IUCN, por sus siglas en inglés). Posteriormente, para evaluar el estado de conservación de los árboles, los investigadores superpusieron mapas de distribución de las especies arbóreas seleccionadas sobre mapas de la Base de Datos Mundial de Áreas Protegidas.

De las 4,046 especies arbóreas analizadas, encontraron que 1,867 están en peligro de extinción. México fue el único país que tenía especies arbóreas extintas en la base de datos, o extintas en estado silvestre. En los árboles existentes, México y Costa Rica presentaron el mayor número de especies amenazadas, con 888 y 227, respectivamente. La amenaza más común en general fue la pérdida de hábitat debido a la expansión agrícola.

La mayoría de las especies (3,349) contaban con al menos un punto de datos dentro de un área protegida. Sin embargo, el 72% de las especies mesoamericanas en áreas protegidas están amenazadas.

Un enfoque personalizado

Neptalí Ramírez Marcial no participó en la nueva investigación, pero como jefe del grupo de restauración del South Border College en México, trabaja con especies arbóreas que se encuentran en diferentes categorías de amenaza. Los bosques de Chiapas, donde él y sus colegas residen, solían estar repletos de encinos, que albergaban altos niveles de biodiversidad. Debido a la influencia humana, ahora hay más pinos que encinos, y el clima es menos favorable para las especies sensibles de la Lista Roja de la UICN.

A pesar del uso de la Lista Roja por parte de Ramírez Marcial, este se mantiene crítico con la herramienta y su uso en la investigación. Por ejemplo, señaló que la nueva evaluación de árboles mesoamericanos clasifica a la Furcraea macdougallii (planta del siglo de MacDougall) como extinta en México. Ramírez Marcial cree que esta planta es similar al agave y no debería considerarse un árbol en absoluto, por lo cual no debería incluirse en el estudio.

También señaló que el nuevo estudio considera a todo México como parte de Mesoamérica. Desde el punto de vista ecológico, dijo, la región biogeográfica mesoamericana se extiende solamente por el centro de México y excluye la parte norte del país, la cual tiene ecosistemas discretos no compartidos con Centroamérica.

Ocotea monteverdensis “pasó de no estar siquiera incluido en la lista a estar en la categoría de conservación más vulnerable”.

Ramírez Marcial coincidió con las conclusiones del nuevo estudio, sin embargo, argumenta que: las estrategias de restauración deben considerar la biodiversidad de las áreas que se desean proteger. Por ejemplo, señaló que los programas del gobierno mexicano priorizan la distribución de pinos para la reforestación en todo el país, en lugar de diseñar estrategias definidas para cada región.

Daniela Quesada, conservacionista del Instituto Monteverde en Costa Rica, afirmó que el nuevo estudio ofrece una visión más completa del estado de los árboles en Mesoamérica. No obstante, al igual que Ramírez Marcial, considera la información de la Lista Roja de la UICN como un punto de partida para la investigación. La exactitud de la Lista Roja, explicó, depende de la cantidad de información que se le presente.

Quesada apuntó que el siguiente paso para la conservación de los árboles en Mesoamérica es que los científicos “analicen con más detalle cada especie que apareció” en el nuevo estudio. Un análisis riguroso de la presencia e influencia de cada especie en cada región podría influir en el desarrollo de proyectos de conservación determinados.

Como ejemplo, mencionó el caso de Ocotea monteverdensis, un árbol que “pasó de no estar siquiera incluido en la lista a estar en la categoría de conservación más vulnerable” (en peligro crítico) gracias al trabajo del ecólogo John Devereux Joslin Jr. Este reconocimiento condujo al desarrollo de un programa comunitario de conservación específico y continuo para este árbol.

—Roberto González (@perrobertogg.bsky.social), Escritor de ciencia

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