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Publication date: Available online 23 October 2025

Source: Advances in Space Research

Author(s): Jian Li, Gang Zhang

Publication date: Available online 22 October 2025

Source: Advances in Space Research

Author(s): Soraya Makhlouf, Mourad Djebli

Publication date: Available online 22 October 2025

Source: Advances in Space Research

Author(s): Bin Chen, Xiaodong Shao, Haoyang Yang, Dongyu Li, Qinglei Hu

Publication date: Available online 22 October 2025

Source: Advances in Space Research

Author(s): Wojciech Jarmołowski, Paweł Wielgosz, Anna Krypiak-Gregorczyk, Beata Milanowska

On an evening 10 years ago, Porter Ranch resident Matt Pakucko stepped out of his music studio and was walloped by the smell of gas—like sticking your head in an oven, he recalled.

SummaryCoseismic slip models for large (Mw > 7) strike-slip earthquakes present a variety of shallow slip deficit (SSD). Accurate estimate of SSD is difficult, and it has been suggested that SSD are to some degree associated with fault-zone characteristics, incompleteness of data coverage as well as simplified model assumptions. Furthermore, SSD can also be sensitive to the amount of model smoothness adopted. Since phase gradient are sensitive to the missing shallow slip from our simulated data, we performed a synthetic test and presented a case study of the 2019 Ridgecrest earthquake sequence to validate that phase gradient from radar interferometry could help reveal the actual SSD for kinematic slip models even without enough near-fault observation. Our results indicate that even in the presence of a greater degree of observational gaps, the phase gradient can still nearly substitute for near-fault observations in constraining the shallow slip. Lastly, we provide a preferred coseismic slip model constrained by all available observations including phase gradient, but with 4-km data gap near the fault trace. This model results in ∼35% SSD for the Ridgecrest earthquakes, matching previous estimates that incorporate near-field data. Considering the phase gradient approach is a straightforward mathematical operation, this approach may be applicable to other types of earthquakes. Notably, due to the smaller amplitude and lower signal-to-noise ratio for the phase gradient data, one needs to carefully balance the trade-offs among weights of different datasets and model smoothness.

SummaryElectrokinetic signals, such as surface self-potential (SP) variations, offer a unique window into coupled fluid–electrical processes in the Earth’s crust, yet their quantitative interpretation remains challenging in complex geological settings. In this study, we develop an electrokinetic modeling framework by extending the modified Luco-Apsel-Chen generalized reflection and transmission method to simulate SP responses due to a fluid-injection source in layered geological media. After simulating electric signals, we apply location-specific amplification factors—derived from prior numerical investigations—that account for the effects of steel well casings. This post-processing step enables rigorous comparison with field observations. Using the well-documented deep fluid injection experiment at the Soultz-sous-Forêts geothermal site, we calibrate simulated pore pressure against downhole measurements to derive a realistic source function for direct comparison between modeled and observed SP signals. The model reproduces key spatiotemporal features of the mV-scale SP anomalies and, importantly, captures the observed slower decay of surface SP signals after shut-in despite the rapid decrease in deep pore pressure. Previous field-scale studies have qualitatively attributed this phenomenon to sustained ionic transport; here, our simulation results provide a quantitative demonstration that this process—driven by continued pore-fluid movement—is responsible for the slower SP decay, a mechanism not captured in earlier electrokinetic simulations. These findings provide new mechanistic insight into SP generation in stratified media, demonstrate the essential role of casing effects in field-scale interpretation, and establish a transferable framework for monitoring subsurface fluid flow in geothermal, hydrocarbon, and groundwater systems.

More than half of Tasmania's largest wetland system in kanamaluka / the Tamar River has vanished since European settlement, new research from the University of Tasmania has revealed.

Permafrost thaw can stimulate the release of soil carbon, triggering a positive carbon-climate feedback that may be mediated by changes in soil phosphorus (P) availability.

As global warming continues to reshape Earth's climate, both the occurrence and mechanisms of extreme precipitation events, such as rain and snow, are undergoing profound transformation. These changes in frequency and intensity directly affect agricultural security, ecosystem stability, and infrastructure resilience.

The deep ocean has long been viewed as a quiet realm, largely isolated from the dynamic processes that shape Earth's climate. However, new observations in the western equatorial Pacific have revealed robust intraseasonal variability at depths of 1,500–3,000 meters, with kinetic energy levels reaching up to 10 cm2s-2.

Researchers at University of Tsukuba have identified the source and the factors affecting the radioactive cesium (137Cs) flow to the port of the Fukushima Daiichi Nuclear Power Plant via its drainage channels. Using tritium in groundwater that leaked from contaminated water storage tanks as a hydrological tracer, they estimated that ~50% of 137Cs comes from "roof drainage" of the rainwater falling on the reactor buildings. The research is published in the journal Water Research.

A new paper describes a rock avalanche in Greenland about 10,900 years BP that had a volume of over 1 billion cubic metres and that travelled almost 16 kilometres.

A fascinating paper (Pedersen et al. 2026) has just been published in the journal Geomorphology that describes a newly-discovered ancient rock avalanche in Greenland. This landslide, which is located in the Tupaasat Valley, is truly enormous. The authors estimate that it has a volume that exceeds 1 km3 (1 billion m3), with a runout distance of 15.8 kilometres and a vertical height difference of 1,440 metres.

The rear scar of the landslide is located at [60.4117, -44.2791]. It is really hard to capture this landslide on Google Earth, but fortunately the paper has been published under a creative commons licence. Here, therefore, is a map of the landslide by Pedersen et al. (2026):-

A) Geomorphological map of the Tupaasat rock avalanche deposits within the landslide outline together with the paleo-sea level line at 10 m a.s.l., and the proposed paleo-ice sheet extent.
B) Map showing the bathymetry data and the landslide outline. The bathymetry data is acquired from the Danish Geodata Agency and is not suitable for navigation C) Cross-section of Tupaasat rock avalanche with columns indicating the geomorphological features described in the results. The terrain slopes are presented below.
Images from Pedersen et al. (2026).

I have quickly annotated a Google Earth image of the site, showing the source and the track of the landslide. Note that the toe extends into the fjord, and thus is underwater, by a couple of kilometres:-

Annotated Google Earth image showing of the Tupaasat rock avalanche.

Landslides on this scale are hard to fathom. If this volume of rock was standing on a standard American football field (110 m x 49 m) it would form a column 185.5 km tall.

Pedersen et al. (2026) have dated the time of occurrence of this landslide. They conclude that it occurred about 10,900 years ago. This coincides remarkably well with the dated deglaciation (retreat of the icesheets) in this area. Thus, the authors suggest that the instability was probably associated with debuttressing of the glacier (i.e. the removal of the ice adjacent to the slope. They cannot rule out the possibility that final failure might have been triggered by an earthquake, though.

A further intriguing question is whether the event triggered a tsunami in the fjord. The distance that the landslide has moved suggests that it was very energetic. Given that it extended to the water (and some of the deposit is now within the lake) it is extremely likely that a displacement wave was triggered.

The latter point is very pertinent as there is increasing concern about the dangers of giant rock slope failures generating damaging tsunami events in fjords. For example, CNN published an article this week in the aftermath of the Tracy Arm landslide and tsunami that highlights the risk to cruise ships. It notes that:

Alaska’s foremost expert on these landslides knows why there hasn’t been a deadly landslide-turn-tsunami disaster, yet: sheer luck.

“It’s not because this isn’t a hazard,” said geologist Bretwood Higman, co-founder and executive director of nonprofit Ground Truth Alaska. “It’s because it just hasn’t happened to be above someone’s house or next to a cruise ship.”

An additional piece of context is the remarkable flooding that occurred in Alaska last weekend as Typhoon Halong tracked across parts of the state. This appears to have received far less attention than might have been anticipated, at least outside the US.

It is surely only a matter of time before we see a really large-scale accident as a result of a tsunami triggered by a rock slope failure. A vey serious scenario is that a large cruise ship is overwhelmed and sunk. The loss of life could be very high.

Reference

L.L. Pedersen et al. 2026. A giant Early Holocene tsunamigenic rock-ice avalanche in South Greenland preconditioned by glacial debuttressing. Geomorphology, 492, 110057,
https://doi.org/10.1016/j.geomorph.2025.110057.

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.

Uranus’s tiny moon Ariel may have had a subsurface ocean that made up around 55% of its total volume. By mapping craters, crags, and ridges on the moon’s surface, planetary scientists modeled how thick Ariel’s crust was before it cracked under tidal stress and created the geologic features seen today. By subtracting the size of the crust and core, the researchers found that the Arielian ocean could have been about 170 kilometers thick as recently as 1 billion years ago.

“If Ariel had a subsurface ocean, it definitely does imply that other small icy moons could also have [had] subsurface oceans,” said Caleb Strom, who conducted this research as a planetary geologist fellow at the University of North Dakota in Grand Forks.

Maybe “it’s easier to make an ocean world than we thought,” he added.

An Unlikely Ocean World

Ariel is the second closest of the five large moons of Uranus. But large is a bit of a misnomer, as Ariel is only about 1,160 kilometers across, or about a third the size of Earth’s Moon.

When Voyager 2 flew through the Uranus system in 1986, scientists were surprised to see that Ariel’s icy surface was relatively young, was geologically complex, and showed some signs of cryovolcanism. Some features on the moon’s surface are similar to those seen on Europa, Enceladus, and Triton, three confirmed ocean worlds.

“We weren’t necessarily expecting it to be an ocean world.”

“What’s interesting about Ariel is that it’s unexpected,” Strom said. “We weren’t necessarily expecting it to be an ocean world.”

Later studies also found ammonia and carbon oxide compounds on Ariel’s surface, chemistry that often suggests the presence of subsurface liquid. The molecules disappear quickly unless they are frequently replenished.

But with Ariel being so small and unable to retain heat for very long, scientists thought that any subsurface ocean it may once have had was relatively thin and short-lived.

Strom and his colleagues didn’t initially set out to challenge this understanding of Ariel’s interior. They were interested in understanding the forces that could have created the moon’s geologic features.

To do this, the researchers first mapped the moon’s surface using images from the Voyager 2 flyby, cataloging ridges, fractures, and craters. They then modeled Ariel’s internal structure, giving it, from the top down, a brittle crust, a flexible crust, and an ocean all atop a solid core. They then simulated how that crust would deform under different levels of stress from tidal forces from other nearby Uranian moons and the planet itself. By varying the crust and ocean thickness and the strength of the tidal stress, the team sought to match the stress features in their models to the Voyager-derived geologic maps.

In 2023, the James Webb Space Telescope imaged Uranus and several of its major moons and rings. Credit: NASA, ESA, CSA, STScI; Image Processing: Joseph DePasquale (STScI)

The team’s models indicate that a crust less than 30 kilometers thick would have fractured under a moderate amount of tidal stress and created the geologic features seen today. The researchers suggest that to cause that stress, in the past 1–2 billion years (Ga), an orbital resonance with nearby moon Miranda stretched Ariel’s orbit about 4% from circular and fractured the surface.

“This is really a prediction about the crustal thickness” and the stress level it can withstand, Strom said. Then, with a core 740 kilometers across and a crust 30 kilometers thick, that would mean that Ariel’s subsurface ocean was 170 kilometers from top to bottom and made up about 55% of its total volume. The researchers published their results in Icarus in September.

Is Ariel Odd? Maybe Not

“The possible presence of an ocean in Ariel in the past [roughly] 1 Ga is certainly an exciting prospect,” said Richard Cartwright, an ocean world scientist at Johns Hopkins Applied Physics Laboratory (JHUAPL) in Laurel, Md. “These results track with other studies that suggest the surface geology of Ariel offers key clues in terms of recent activity” and the possibility that Ariel is, or was, an ocean world. Cartwright was not involved with the new research.

Strom cautioned that just because Ariel once had a substantial subsurface ocean doesn’t mean that it still does. The moon is very small and doesn’t retain heat very well, he said. Any ocean that remained would likely be much thinner and probably not a good place to search for life.

However, the fact that tiny Ariel may once have had such a large ocean may mean that ocean worlds are more common and easier to create than scientists once thought. Understanding the conditions that led to Ariel’s subsurface ocean could help scientists better understand how such worlds come about and how they evolve.

“Ariel’s case demonstrates that even comparatively sized moons can, under the right conditions, develop and sustain significant internal oceans.”

“Ariel’s case demonstrates that even comparatively sized moons can, under the right conditions, develop and sustain significant internal oceans,” said Chloe Beddingfield, a planetary scientist also at JHUAPL. “However, that doesn’t mean all similar bodies would have done so. Each moon’s potential for an ocean depends on its particular mix of heat sources, chemistry, and orbital evolution.”

An ocean composing 55% of a planet’s or moon’s total volume might seem pretty huge, but it also might be perfectly within normal range for ocean worlds, added Beddingfield, who was not involved with this research. “The estimated thickness of Ariel’s internal ocean…is striking, but not necessarily unexpected given the diversity of icy satellites.”

Too, Voyager 2 did not image all of Ariel’s surface, only the 35% that was illuminated during its flyby. A future long-term mission to the Uranus system could provide higher-resolution global maps of Ariel and other moons to help refine calculations of crustal thickness and determine the existence of subsurface oceans, Strom said.

Strom and his team plan to expand their stress test research to other moons of Uranus such as Miranda, Oberon, and Umbriel and possibly icy moons around other planets.

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

Citation: Cartier, K. M. S. (2025), Tiny Uranian moon likely had a massive subsurface ocean, Eos, 106, https://doi.org/10.1029/2025EO250398. Published on 24 October 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.

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

Los suelos árticos y subárticos almacenan una proporción considerable del carbono de la Tierra. Sin embargo, el aumento de las temperaturas podría drenar el nitrógeno de estos suelos — un nutriente clave —. Según un nuevo estudio, la pérdida de nitrógeno podría reducir el crecimiento de las plantas, limitando la capacidad de los suelos para almacenar carbono y amplificando el calentamiento global.

Los suelos de latitudes altas almacenan grandes cantidades de carbono porque las bajas temperaturas retardan la actividad microbiana. Aunque las plantas producen materia orgánica a través de la fotosíntesis, los microorganismos no pueden consumirla lo suficientemente rápido, provocando su acumulación con el tiempo. Los científicos han estado preocupados de que un Ártico más cálido aceleraría la actividad microbiana, liberando el carbono almacenado a la atmósfera como dióxido de carbono (CO₂). Pero también esperaban que las temperaturas más cálidas estimularan el crecimiento de las plantas, lo que reabsorbería parte del carbono y compensaría parcialmente estas emisiones.

La nueva investigación muestra que este último escenario es muy improbable, ya que el calentamiento provoca que los suelos pierdan nitrógeno, una pérdida que podría inhibir el crecimiento de las plantas.

“No esperábamos ver una pérdida de nitrógeno.”

Los hallazgos provienen de un experimento de una década de duración realizado en un pastizal subártico cerca de Hveragerði, Islandia. En 2008, un potente terremoto alteró los flujos de agua geotérmica en la región, convirtiendo parcelas de suelo que antes eran normales en zonas calentadas naturalmente con gradientes de temperatura que oscilan entre 0.5 °C y 40 °C por encima de los niveles anteriores. El evento creó un laboratorio natural único para observar cómo responden los ecosistemas al calentamiento a largo plazo.

Usando isótopos estables de nitrógeno-15 para rastrear los flujos de nutrientes en el paisaje, los investigadores encontraron que, por cada grado Celsius de calentamiento, los suelos pierden entre 1.7 % y 2.6 % de su nitrógeno. Las mayores pérdidas ocurrieron durante el invierno y principios de la primavera, cuando los microbios permanecían activos pero las plantas estaban inactivas. Durante este tiempo, se liberaron compuestos nitrogenados como el amonio y el nitrato en el suelo, pero las plantas no podían absorberlos, se perdieron ya sea por lixiviación al agua subterránea o escapándose a la atmósfera como óxido nitroso, un gas de efecto invernadero casi 300 veces más potente que el CO₂.

Los resultados se publicaron en un artículo en Global Change Biology.

«No esperábamos ver una pérdida de nitrógeno», mencionó Sara Marañón, científica del suelo del Centro de Investigación Ecológica y Aplicaciones Forestales de España y primera autora del estudio. «Los mecanismos del suelo para almacenar nitrógeno se están deteriorando».

Un ecosistema menos fértil, más rápido

Los investigadores también encontraron que el calentamiento debilitó los mecanismos que ayudan a los suelos a retener el nitrógeno. En las parcelas más cálidas, la biomasa microbiana y la densidad de las raíces finas — ambas fundamentales para el almacenamiento de nitrógeno — eran mucho menores que en las parcelas más frías. Aunque los microbios eran menos abundantes, su metabolismo era más rápido, liberando más CO2 por unidad de biomasa. Mientras tanto, las plantas luchaban por adaptarse, quedando rezagadas tanto en su crecimiento como en la absorción de nutrientes.

«Las comunidades microbianas son capaces de adaptarse y alcanzar un nuevo equilibrio con tasas de actividad más rápidas», dijo Marañón. «Pero las plantas no pueden seguirles el ritmo»

“Este no es un mensaje muy optimista.”

El aumento del metabolismo microbiano resulta inicialmente en un mayor consumo del nitrógeno y carbono disponibles en el suelo. Sin embargo, después de 5 o 10 años, el sistema parece alcanzar un nuevo equilibrio, con niveles reducidos de materia orgánica y menor fertilidad. Ese cambio sugiere que el calentamiento de los suelos puede provocar una transición hacia un estado permanentemente menos fértil, haciendo más difícil la recuperación de la vegetación y conduciendo a una pérdida irreversible de carbono.

Tradicionalmente, los científicos han pensado que, dado que la materia orgánica se descompone más rápidamente en un clima más cálido, el nitrógeno que contiene estará más disponible, lo que conducirá a una mayor productividad, según Erik Verbruggen, ecólogo del suelo de la Universidad de Amberes, en Bélgica, que no participó en el estudio. «Este artículo demuestra que, en realidad, esto no está ocurriendo».

En cambio, el nitrógeno está siendo filtrado del suelo durante la primavera, lo que lo hace inaccesible para una mayor producción de biomasa. «Este no es un mensaje muy optimista», afirmó Verbruggen.

Una fuente subestimada de gases de efecto invernadero

Dado que las regiones árticas se están calentando más rápido que el promedio global, esta alteración del ciclo de nutrientes podría volverse más evidente pronto. La pérdida de nitrógeno y carbono de los suelos en regiones frías puede representar una fuente significativa y previamente subestimada de emisiones de gases de efecto invernadero, que los modelos climáticos actuales aún no han incorporado por completo.

Los investigadores regresaban periódicamente a los cálidos pastizales cercanos a Hveragerði, Islandia, para medir el nitrógeno. Crédito: Sara Marañón.

Los investigadores planean explorar las fases tempranas del calentamiento del suelo, trasplantando fragmentos de suelos normales hacia áreas calentadas, y también investigar cómo distintos tipos de suelo responden al calor. Marañón señaló que los suelos islandeses estudiados son de origen volcánico y muy ricos en minerales, a diferencia de los suelos orgánicos de turba comunes en otras regiones árticas.

“Los suelos árticos también incluyen el permafrost en lugares como el norte de Rusia y partes de Escandinavia, y ellos son los mayores reservorios de carbono en los suelos del mundo”, dice Verbruggen. Por otro lado, los suelos analizados en esta investigación eran suelos de pastizal someros. “No son necesariamente representativos de todos los suelos árticos.”

Aun así, Verbruggen añadió, los hallazgos del estudio resaltan el delicado equilibrio entre productividad y pérdida de nutrientes en estos sistemas.

Las abundantes reservas de carbono del suelo lo convierten en un riesgo importante si se gestiona inadecuadamente, dijo Marañón. «Pero también puede convertirse en un aliado potencial y compensar las emisiones de CO2».

—Javier Barbuzano (@javibar.bsky.social), Escritor 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.

In recent years, the international community has made progress in slowing increases in the rate of carbon dioxide emissions and in acknowledging the scale of methane leaks from oil and gas facilities. However, carbon dioxide emissions continue to rise, methane releases from the energy sector have not abated, and there is more need than ever for targeted and sustained greenhouse gas (GHG) emissions reductions and other climate change mitigation approaches.

The success of climate change mitigation approaches relies in part on having accurate, timely, and integrated carbon cycle data from surface, airborne, and satellite sensors.

The success of such actions relies in part on having accurate, timely, and integrated carbon cycle data from surface, airborne, and satellite sensors covering local, regional, and international scales. These data improve efforts to track emissions reductions, identify and mitigate unexpected emissions and leaks, and monitor ecosystem feedbacks to inform land management.

In September 2024, researchers in the carbon cycle monitoring community met to discuss how best to establish a more effective system for monitoring GHGs and to help accelerate climate action through better data and decision support.

Here we highlight issues and challenges facing emissions monitoring and documentation efforts illuminated during the September meeting, as well as ideas and proposals for tackling the challenges. The recommendations emphasize the urgency of enhanced monitoring to support the goals of the Paris Agreement and the Global Methane Pledge, particularly in the face of increasing climate extremes and the vulnerability of Earth’s natural carbon reservoirs [Friedlingstein et al., 2025].

Bottom-Up Meets Top-Down

Parties to the Paris Agreement track their progress toward meeting GHG emissions reduction targets through bottom-up accounting methods that track carbon using local ground-based observations. These methods combine information about the spatial extents of carbon sources and sinks with estimates of how much these sources and sinks emit or take up, respectively.

This inventorying approach offers high-precision information at time intervals that support long-term tracking. However, it is also often time intensive, depends on country-specific methodologies, may not accurately reflect spatiotemporal variability in GHG fluxes, and is not suited for operational monitoring of sudden changes or reversals [Elguindi et al., 2020; Nicholls et al., 2015].

Top-down approaches using remotely sensed atmospheric GHG and biomass observations offer an independent accounting method [Friedlingstein et al., 2025], with the potential for low-latency (weekly to monthly) monitoring of GHG emissions and removals. Technological advances offered by facility-scale plume imagers (e.g., GHGSat, Earth Surface Mineral Dust Source Investigation (EMIT), Carbon Mapper) and global GHG mappers (e.g., Orbiting Carbon Observatory-2 and -3 (OCO-2 and -3), Tropospheric Monitoring Instrument (TROPOMI), Greenhouse gases Observing Satellite-2 (GOSAT-2)) show promise for monitoring GHG fluxes at the local and global scale, respectively [Joint CEOS-CGMS Working Group on Climate Greenhouse Gas Task Team, 2024].

Greenhouse gas (GHG) observations with existing capabilities alone are insufficient for adequately informing climate change mitigation measures.

However, a significant gap remains in our ability to monitor weaker, spatially distributed emissions and removals at intermediate (10- to 1,000-kilometer) scales [Joint CEOS-CGMS Working Group on Climate Greenhouse Gas Task Team, 2024], particularly in systems managed by humans such as energy production and land use.

Conversations during the 2024 workshop—partly intended to inform the development of the next Decadal Survey for Earth Science and Applications from Space—highlighted limitations in current GHG monitoring capabilities. They also emphasized the critical need for an operational observing system that leverages top-down and bottom-up approaches to support climate action at local, national, and international scales.

Because of a lack of sensitivity to subregional processes, GHG observations with existing capabilities alone are insufficient for adequately informing climate change mitigation measures [e.g., Jacob et al., 2022; Watine-Guiu et al., 2023]. We must also integrate state-of-the-art science and improved understanding of Earth’s changing carbon cycle, as well as data from new observing system technologies, into the information provided to decisionmakers.

This integration requires identifying gaps and opportunities with respect to knowledge, data, and stakeholder needs. It also requires defining a vision for sustained, operational GHG monitoring to support emissions reductions, track carbon cycle feedbacks, and deliver reliable, timely, transparent, and actionable information.

This vision could be achieved with a unified multitiered global system combining models and observations of the atmosphere, land, and ocean collected with surface, airborne, and satellite tools to track carbon fluxes (e.g., atmospheric emissions and removals) and stocks (e.g., biomass, soil carbon) with improved frequency, spatial coverage, and precision (Figure 1).

Fig. 1. An effective multitiered greenhouse gas (GHG) observing system should integrate observations of the atmosphere, land, and ocean from sensors and samples on Earth’s surface, in the air, and aboard satellites. Carbon dioxide is shown as black and red molecules, and methane is shown as black and white molecules. ARGO refers to a fleet of sensors floating in the upper ocean. FTIR is Fourier transform infrared spectroscopy. Credit: Created in BioRender; Carroll, 2025, https://BioRender.com/b77439n

Organizing such a system would require substantial international coordination among governmental, academic, and nongovernmental organizations, perhaps mediated through entities such as the World Meteorological Organization’s Global Greenhouse Gas Watch, the Committee on Earth Observation Satellites, and the U.S. Greenhouse Gas Center (USGHGC).

Addressing Gaps from Space

A globally unified GHG observing system should capitalize on spaceborne technologies to fill spatial and temporal gaps in in situ networks and to monitor the responses of carbon fluxes and stocks to disturbances, weather extremes, and environmental change. This system should prioritize four key elements.

First, gathering more vertically detailed data—from the top of the atmosphere to ground level—is critical. Existing satellites measure the total amounts of carbon dioxide and methane in the atmospheric column. These measurements work well for detecting changes over large (e.g., continental) spatial scales and at facility scale, but they provide less detail about smaller-scale processes. Knowing GHG concentrations near the surface relative to those in the upper atmosphere could, for example, provide improved tracking of fluxes and understanding of the processes responsible.

Sustained vertical GHG profiling, achieved using multichannel passive sensors deployed on missions such as GOSAT-2 or emerging cloud-slicing lidar methods, for example, is foundational to the proposed system. This profiling would provide long-term time series data to help researchers detect weak but consistent flux changes and increased sensitivity to natural and anthropogenic regional sources [e.g., Parazoo et al., 2016].

Sampling the atmosphere every day would enable better detection of sudden changes in GHG concentrations and linking of those changes to particular sources.

Second, more frequent observations—obtained with a constellation of satellites observing from low, geostationary, and highly elliptical Earth orbits—are needed. Sampling the atmosphere every day, or even multiple times per day, would enable better detection of sudden changes in GHG concentrations and linking of those changes to particular sources.

Third, mapping of carbon stocks should be harmonized by combining information from different sensors and methods. Several means exist to map carbon in vegetation from space, for example, including lidar altimetry used to identify treetops and synthetic aperture radar used to estimate the volumes of trees.

Combining the strengths of existing methods and missions would facilitate more accurate and better resolved monitoring of carbon accumulation and loss due to management practices, disturbances, and ecosystem recovery. Future biomass satellite missions should focus on measurements at the scale of forest plots (i.e., hectare-scale systems with many trees) to provide more useful maps with reduced uncertainty, rather than on applying very high resolution sensors that resolve individual trees.

The fourth key is expanded satellite coverage of tropical, high-latitude, and oceanic regions to better monitor carbon cycle feedbacks [Sellers et al., 2018]. This coverage should involve the use of new active and imaging spectrometer techniques, such as those being developed in the Carbon-I mission concept study, to probe through prevalent clouds and darkness that hinder continuous monitoring.

Beyond the primary focus on GHG and biomass data, we also need—and have opportunities to obtain—complementary datasets to better constrain the locations of and processes affecting carbon sources and sinks. Atmospheric measurements of solar-induced fluorescence by vegetation, carbonyl sulfide, oxygen, carbon monoxide, and isotopes of carbon and oxygen could help disentangle fossil sources of emissions from biological sources and provide insights into processes such as photosynthesis and wildfire activity.

Currently, land and ocean ecosystems remove about half of the anthropogenic carbon emitted into the atmosphere, but this amount could change in the future [Friedlingstein et al., 2025]. Sustained monitoring of these ecosystems—and of the indicators of how they are changing—is necessary to understand and track diverse change across the Earth system.

Addressing Gaps from the Ground

Surface and airborne observations are essential for calibrating spaceborne measurements and for monitoring processes that can’t be observed from space.

Expanded surface and airborne networks for gathering data in situ from oceanic, terrestrial, and aquatic ecosystems are also a critical part of the proposed global observing system. These observations are essential for calibrating spaceborne measurements, for improving our understanding of undersampled regions (e.g., nonforest lands, rivers, wetlands, oceans), and for monitoring processes that can’t be observed from space.

Efforts on several fronts are required to provide more comprehensive ground- and air-based information on carbon fluxes and stocks to better meet stakeholder and research needs. Examples of these needed efforts include obtaining more atmospheric GHG profiles from research and commercial aircraft (e.g., through campaigns such as NOAA’s National Observations of Greenhouse Gasses Aircraft Profiles program), expanding measurements of surface-atmosphere GHG exchanges from tower-mounted sensors in undersampled terrestrial and aquatic systems [Baldocchi, 2020], and collecting seawater composition data from autonomous vehicles (e.g., Argo floats) in coastal and open oceans.

Other needed efforts include collecting more in situ measurements of above- and below-ground biomass and soil carbon and airborne sampling of managed and unmanaged (natural) experimental field sites. For example, monitoring of biomass reference measurement networks, such as GEO-TREES, should be expanded to facilitate monitoring and validation of spaceborne biomass data. These complementary measurements of quantities unobserved by remote sensing, such as soil carbon and respiration, are essential for tracking long-term storage [e.g., Konings et al., 2019].

Connecting Users to Data

Workshop participants envisioned a framework to support decisionmaking by scientists and stakeholders that links observing systems with actionable knowledge through a two-way flow of information. This framework involves three key pieces.

Identifying the underlying causes and drivers of changes in GHG emissions and removals is critical for developing effective, targeted mitigation and management policies.

First, integrating information from data-constrained models is crucial. Guan et al. [2023] offered a “system of systems” approach for monitoring agricultural carbon that is also applicable to other ecosystems. This approach leverages multitiered GHG and biomass data as constraints in land, ocean, and inverse models (which start with observed effects and work to determine their causes) to generate multiscale maps of observable and unobservable carbon stock and flux change. The result is a stream of continuous, low-latency information (having minimal delays between information gathering and output) for verifying GHG mitigation strategies.

Second, scientists must work with stakeholders to identify the underlying causes and drivers of changes in GHG emissions and removals. This identification is critical for assessing progress and developing effective, targeted mitigation and management policies.

Third, the actionable knowledge resulting from this framework—and provided through organizations such as the USGHGC—must be applied in practice. Stakeholders, including corporations, regulatory agencies, and policymakers at all levels of government, should use improved understanding of carbon flux change and underlying drivers to track progress toward nationally determined contributions, inform carbon markets, and evaluate near- and long-term GHG mitigation strategies.

Meeting the Needs of the Future

Benchmarking and validation are important parts of building trust in models and improving projections of carbon-climate feedbacks. By using comprehensive observations of carbon fluxes and stocks to assess the performance of Earth system models [e.g., Giorgetta et al., 2013], scientists can generate more reliable predictions to inform climate action policies that, for example, adjust carbon neutrality targets or further augment GHG observing systems to better study regional feedbacks [Ciais et al., 2014].

The globally unified observing system envisioned, which would integrate advanced spaceborne technologies with expanded ground and air networks and a robust decision support framework, could significantly enhance our ability to track and mitigate GHG emissions and manage carbon stocks.

Successful implementation of this system would also hinge on data accessibility and community building. Developing a universal data platform with a straightforward interface that prioritizes data literacy is crucial for ensuring accessibility for a global community of users. In addition, fostering cross-agency partnerships and engagement and collaborative networking opportunities among stakeholders will be essential for building trust, catalyzing further participation in science, and developing innovative solutions for a more sustainable future.

Acknowledgments

The September 2024 workshop and work by the authors on this article were funded as an unsolicited proposal (Proposal #226264: In support of ‘Carbon Stocks Workshop: Sep 23–25, 2024’) by the U.S. Greenhouse Gas Center, Earth Science Division, NASA. A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004).

References

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Ciais, P., et al. (2014), Current systematic carbon-cycle observations and the need for implementing a policy-relevant carbon observing system, Biogeosciences, 11(13), 3,547–3,602, https://doi.org/10.5194/bg-11-3547-2014.

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Guan, K., et al. (2023), A scalable framework for quantifying field-level agricultural carbon outcomes, Earth Sci. Rev., 243, 104462, https://doi.org/10.1016/j.earscirev.2023.104462.

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Author Information

Dustin Carroll (dustin.carroll@sjsu.edu), Moss Landing Marine Laboratories, San José State University, San José, Calif.; also at Jet Propulsion Laboratory, California Institute of Technology, Pasadena; Nick Parazoo and Hannah Nesser, Jet Propulsion Laboratory, California Institute of Technology, Pasadena; Yinon Bar-On, California Institute of Technology, Pasadena; also at Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel; and Zoe Pierrat, Jet Propulsion Laboratory, California Institute of Technology, Pasadena

Citation: Carroll, D., N. Parazoo, H. Nesser, Y. Bar-On, and Z. Pierrat (2025), A better way to monitor greenhouse gases, Eos, 106, https://doi.org/10.1029/2025EO250395. Published on 24 October 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.

Author(s): Prabhat Singh and Punit Kumar

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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.

A large swath of the Arctic National Wildlife Refuge (ANWR) will soon open for drilling, the Trump administration announced today.

“For too long, many politicians and policymakers in DC treated Alaska like it was some kind of zoo or reserve, and that, somehow, by not empowering the people or having even the slightest ability to tap into the vast resources was somehow good for the country or good for Alaska,” Secretary of the Interior Doug Burgum said during an Alaska Day event.

As of July 2025, Alaska ranked sixth in the nation for crude oil production.

 
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The news is the latest in a saga involving the ANWR, which in total spans 19.6 million acres. The 1.5 million acres to be opened for drilling represent the coastal plain of the refuge.

The 1980 Alaska National Interest Lands Conservation Act, which created most of the state’s national park lands, included a provision that no exploratory drilling or production could occur without congressional action.

Trump first opened the 1.5 million-acre coastal plain region for drilling in 2020, but the sale of drilling leases in early 2021 generated just $14.4 million in bids, rather than the $1.8 billion his administration had estimated.

On his first day in office, Biden placed a temporary moratorium on oil and gas drilling in the refuge, later going on to cancel the existing leases.

Trump resumed his efforts to allow drilling in ANWR early in his second term, though in January 2025, a lease sale attracted zero bidders. Previously, major banks had ruled out financing such drilling efforts, some citing environmental concerns. Cost is also likely a factor, as the area currently has no roads or facilities.

In addition to opening drilling, the Department of Interior also announced today the reissuing of permits to build a road through Izembek National Wildlife Refuge and a plan to greenlight another road.

“Today’s Arctic Refuge announcement puts America — and Alaska — last,” said Erik Grafe, an attorney for the environmental law nonprofit Earthjustice, in a statement. “The Gwich’in people, most Americans, and even major banks and insurance companies know the Arctic Refuge is no place to drill.”

In contrast, Voice of the Arctic Iñupiat (VOICE), a nonprofit dedicated “to preserving and advancing North Slope Iñupiat cultural and economic self-determination,” released a statement on Thursday in favor of the policy shift.

“Developing ANWR’s Coastal Plain is vital for Kaktovik’s future,” said Nathan Gordon, Jr., mayor of Kaktovik, an Iñupiat village on the northern edge of ANWR. “Taxation of development infrastructure in our region funds essential services across the North Slope, including water and sewer systems to clinics, roads, and first responders. Today’s actions by the federal government create the conditions for these services to remain available and for continued progress for our communities.”

The Department of the Interior said it plans to reinstate the 2021 leases that were cancelled by the Biden administration, as well as to hold a new lease sale sometime this winter.

—Emily Gardner (@emfurd.bsky.social) Associate Editor

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2025. AGU. CC BY-NC-ND 3.0
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Brazilian researchers have developed a technique that estimates the force exerted on each grain of sand in a dune from images. This method, which is based on numerical simulations and artificial intelligence (AI), transforms the study of granular system dynamics and paves the way for investigating previously unmeasurable physical processes. Applications range from civil engineering to space exploration.