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

 “Everything should be made as simple as possible, but not simpler.” This popular saying paraphrases a sentiment expressed by Einstein about the need for simplicity, though not at the expense of accuracy. Modeling of the Earth’s climate system has become an incredibly complex endeavor, especially when coupling of physics of atmospheric movement with complex and nonlinear feedbacks with the ocean and land surface and forcing by collective human actions. Such complexity can make the underlying causes of model behaviors hard to diagnose and can make it prohibitively expensive to perform targeted experiments.

Two very recent developments, the emergence of kilometer-scale simulations and the rapid growth of machine learning (ML) approaches, have further increased the computational complexity of modeling global climate. In their commentary, Reed et al. [2025] remind us of the benefits of maintaining and applying a hierarchy of models with different levels of complexity. They make a special plea not to forget the power of using idealized, or simplified, climate models for hypothesis testing, model development, and teaching. 

Citation: Reed, K. A., Medeiros, B., Jablonowski, C., Simpson, I. R., Voigt, A., & Wing, A. A. (2025). Why idealized models are more important than ever in Earth system science. AGU Advances, 6, e2025AV001716. https://doi.org/10.1029/2025AV001716

—Susan Trumbore, 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.

On 26 August 2025, a landslide triggered by extraordinary rainfall killed at least 34 people and injured another 20 individuals.

On 26 August 2025, extremely intense late monsoon rainfall struck parts of Jammu and Kashmir in northern India, triggering extensive flooding and landslides. Unfortunately, a significant landslide occurred on the route to the Vaishno Devi shrine, a sacred Hindu site that attracts large numbers of pilgrims. At the time of writing, the reported loss of life is 34 people, with 20 more injured.

I can find little detailed information about this landslide at present – the site is remote and access is clearly extremely difficult. However, this highlights a very major issue that India faces during the monsoon.

The Google Earth image below shows the terrain around the Vaishno Devi shrine (which is located at [33.03004, 74.948032]:-

Google Earth image showing the terrain around the Vaishno Devi shrine in northern India.

The landscape here is steep and geologically vulnerable, and the shrine is located on a remote mountain side, accessed by tracks. There is a good account of making the pilgrimage here – this person started the journey at 19:15 and they arrived at 02:00 the next day. The route is well-established but the journey is long (13 km). Most people travel on foot. According to the temple itself, over 5.2 million people have the journey so far in 2025. Travel during the monsoon is not recommended, but many people inevitably make the trip at this time.

Thus, this pilgrimage, and others that also take devotees into the Himalayas, places people in a dynamic landscape at a time when landslides are most likely. Inevitably, the vulnerability of those people is high. The tragedy at Vaishno Devi is the consequence.

Unfortunately, this event is not isolated. On 14 August, another major landslide occurred at Chasoti in Kishtwar district, also in Jammu and Kashmir, on the route of the Machail Mata Yatra pilgrimage. The final loss of life is unclear, but at least 66 people were killed and some reports suggest as many as 75 more people may be missing. There have been a number of other fatal landslides this year on Hindu pilgrimage routes.

And loyal readers of this blog may remember the 2013 Kedarnath disaster, when vicious debris flows struck the route of the Chardham pilgrimage when it was packed with pilgrims. The remains of 733 victims were recovered, but 3,075 people remain missing. With a total of 3,808 victims, this was one of the worst landslide disasters of the last 30 years.

There are news reports that Jammu and Kashmir chief minister, Omar Abdullah, is questioning why the Shri Mata Vaishno Devi Shrine Board did not suspend the pilgrimage. Reports indicate that the area received 629.4 mm of rainfall in a rolling 24 hour period, exceeding the previous record (342 mm) by a huge margin. In the view of the minister, these totals should have alerted the authorities to the potential for a disaster.

Whilst this is a pertinent question, it is addressing a short term issue, rather considering the underlying problems. The reality is that peak rainfall intensities in the summer monsoon are rapidly increasing across South Asia as a result of climate change, triggering landslides (especially channelised debris flows) and floods. At the same time, huge numbers of pilgrims are travelling into the landscape, where they are extremely vulnerable.

Managing this risk is very taxing, but many more people will lose their lives if systematic action is not taken to protect the pilgrims. These levels of loss cannot be tolerable.

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.

AbstractIntradecadal variations in the length-of-day (ΔLOD) can reveal changes in angular velocity interpreted as due to Earth’s core. Previous studies have identified periodic oscillations of around 6 and 8 years. To complement widely used Fourier methods, we investigate the ΔLOD record from 1962-2025 in the time domain, seeking smooth variations using cubic B-splines. We analyse in several ways. A penalised least-squares spline fit allows isolation of coherent variations from analysing the first and second derivatives. Alternatively, a smooth curve fit with least-squares splines allows removal of the long-period behaviour of ΔLOD. From this, we fit the residual with a pure cosine-wave of varying period but examine the data fits carefully in case the signal is non-stationary (for example from impulsive forcing). All approaches show clear evidence of signals with periods around 5.9 — and in the case for the time derivatives — 8.5 years. We find that the pure 5.9-year oscillation breaks down in 2010, with a one-off peak to peak separation of around 4.7 years. After 2014, the variation is once again consistent with an approximate 6 year oscillation. Such a discontinuous, non-stationary effect is not well-characterised by frequency-domain based methods. Seeking to understand this brief interruption of the 6 year oscillation, we extend the study length using a ΔLOD series from lunar occultation data extending back to 1800, and find it suitable to repeat our spline-based analysis from 1830 onwards. From this, we find the 6 year oscillation stable throughout the entire 19th and 20th century, with the exception of 1916–1920, where we observe a similar interruption of the 6 year variation by a single 4 year oscillation. The 2010 disruption to the 6-year oscillation is contemporary with changes in geomagnetic secular variation, modelled core surface flow, and inner core seismic signature. All of these events suggest a step change in core-processes around 2010.

Supercell thunderstorms are among the most impactful weather events in Europe. They typically occur in summer and are characterized by a rotating updraft of warm, humid air that brings strong winds, large hail and heavy rain. The impact is significant and often leads to property damage, agricultural losses, traffic chaos and even threats to human safety.

A new study led by researchers from the Aerospace Information Research Institute (AIR) of the Chinese Academy of Sciences has for the first time mapped the long-term, large-scale transport pathways of PM2.5 pollution across China spanning from 2000 to 2021, providing scientific support for refining national air quality management strategies.

When water is below normal levels in Latin America, it's not just farmers and consumers who suffer. A new study finds that air pollution spikes, and thousands of people die prematurely as a result.

On August 5, a cloudburst near the Kheer Ganga river triggered a flash flood that tore through Dharali, a village in the Indian Himalayas. Within minutes, the river swelled with water, mud and debris, sweeping away homes, roads and lives.

Research by the University of Southampton and University of East Anglia (UEA) shows a major shift in South Pacific climate conditions—beginning around 1,000 years ago—that may have pushed people to settle further east and move away from increasingly drier conditions in the west.

Microplastics and nanoplastics are not only polluting our oceans, rivers and fields, but also our forests, according to geoscientists at TU Darmstadt. Their research is published in Communications Earth & Environment.

Far beneath the waves, down in the depths of the Japan Trench—seven kilometers below sea level—lie hidden clues about some of the most powerful earthquakes and tsunamis on Earth.

What do the rumblings of Iceland's volcanoes have in common with the now peaceful volcanic islands off Scotland's western coast and the spectacular basalt columns of the Giant's Causeway in Northern Ireland?

The atmosphere will become more turbulent in future decades as climate change makes the air less stable.

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.

Update 27 August 2025: This article has been updated to reflect newly released numbers of staff placed on leave.

On 25 August, 182 current and former staff members of the Federal Emergency Management Agency (FEMA) signed a declaration opposing the Trump administration’s actions to obstruct FEMA’s mission to provide relief and recovery assistance after natural disasters. The following evening, 36 FEMA staff, all signatories of that Katrina Declaration, were placed on indefinite administrative leave.

Colette Delawalla, the executive director of Stand Up for Science, an advocacy group that helped publicize the letter, told the New York Times that the move appeared to be an act of retaliation.

“Once again, we are seeing the federal government retaliate against our civil servants for whistleblowing—which is both illegal and a deep betrayal of the most dedicated among us,” she said.

This is illegal, plain and simple. FEMA workers are doing their duty as public servants by blowing the whistle on the dismantling of their agency — and whistleblowing is protected under federal law.

— Stand Up for Science! (@standupforscience.bsky.social) 2025-08-27T01:25:29.308Z

Employees were told the leave was effective immediately. Stand Up for Science and the Washington Post both confirmed that two of those suspended were taken off duty from recovery work at the site of Texas floods that killed at least 135 people in early July.

The notice of placement on administrative leave stated that the decision “is not a disciplinary action and is not intended to be punitive.” However, FEMA spokesperson Daniel Llargues said in a statement that “It is not surprising that some of the same bureaucrats who presided over decades of inefficiency are now objecting to reform.”

The staff who were placed on administrative leave will receive pay and benefits but do no work.

FEMA staff sent their letter of dissent to Congress 20 years after of Hurricane Katrina, one of the deadliest natural disasters in modern U.S. history. Experts have long argued that many more people died than should have because of human failures in disaster planning and implementation. Twenty years later, FEMA staff have warned that recent changes to the organization’s structure and procedures put the nation at risk for future Katrina-like disasters.

 
Related

•  FEMA employees put on leave after criticizing Trump administration in open letter
•  Read The Katrina Declaration
•  Some FEMA staff are put on leave after signing dissent letter
•  Get Involved: AGU Science Policy Action Center

The letter specifically calls out reductions in disaster workforce, failure to appoint a Senate-confirmed FEMA administrator, elimination or reduction of risk reduction programs, interference with preparedness programs, censorship of climate science, and new policies regarding spending that have already delayed FEMA deployment to disaster areas.

The Katrina Declaration followed similar letters of dissent, also facilitated by Stand Up for Science, from the National Institutes of Health, NSF, EPA, and NASA. Not long after EPA staff sent their letter of dissent, 144 signatories were placed on administrative leave.

Only 36 individuals signed their names to the Katrina Declaration, while the rest chose to remain anonymous, likely in fear of similar retribution. (More people have signed the letter since 25 August, all anonymously.) The fears seem to have been well-founded: All those who signed their name were placed on leave.

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

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

The uplift and outward growth of Asia's three great plateaus is a major driver of changes in the Asian landscape and biodiversity, according to a new study led by Prof. Wang Wei from the Institute of Botany of the Chinese Academy of Sciences (IBCAS).

As the United States passes a tipping point in water security, new research reveals that millions of Americans now face a growing crisis in accessing clean, affordable water.

Volcanic eruptions can have dramatic consequences. But how can we anticipate this phenomenon, which unfolds up to tens of kilometers beneath the surface?

Source: AGU Advances

In recent years, scientists have found that machine learning–based weather models can make weather predictions more quickly using less energy than traditional models. However, many of those models are unable to accurately predict the weather more than 15 days into the future and begin to simulate unrealistic weather by day 60.

The Deep Learning Earth System Model, or DLESyM, is built on two neural networks that run in parallel: One simulates the ocean while the other simulates the atmosphere. During model runs, predictions for the state of the ocean update every four model days. Because atmospheric conditions evolve more rapidly, predictions for the atmosphere update every 12 model hours.

The model’s creators, Cresswell-Clay et al., found that DLESyM closely matches the past observed climate and creates accurate short-term forecasts. Using Earth’s current climate as a baseline, it can also accurately simulate climate and interannual variability over 1,000-year periods in less than 12 hours of computing time. It generally equals or outperforms models based on the Coupled Model Intercomparison Project Phase 6, or CMIP6, which is widely used in computational climate research today.

The DLESyM model outperformed CMIP6 models in replicating tropical cyclones and Indian summer monsoons. It captured the frequency and spatial distribution of Northern Hemisphere atmospheric “blocking” events, which can cause extreme weather, at least as well as CMIP6 models. In addition, the storms the model predicts are also highly realistic. For instance, the structure of a nor’easter generated at the end of a 1,000-year simulation (in 3016) is very similar to a nor’easter observed in 2018.

However, both the new model and CMIP6 models poorly represent Atlantic hurricane climatology. Also, DLESyM is less accurate than other machine learning models for medium-range forecasts, or those made up to about 15 days into the future. Crucially, the DLESyM model only conducts simulations of the current climate, meaning it does not account for anthropogenic climate change.

The key benefit of the DLESyM model, the authors suggest, is that it uses far less computational power than running a CMIP6 model, making it more accessible than traditional models. (AGU Advances, https://doi.org/10.1029/2025AV001706, 2025)

—Madeline Reinsel, Science Writer

Citation: Reinsel, M. (2025), Machine learning simulates 1,000 years of climate, Eos, 106, https://doi.org/10.1029/2025EO250318. Published on 27 August 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.

As a boulder rolls down a cliff slope on the Moon, it kicks up lunar dust, leaving behind a telltale herringbone pattern of ejecta.

In a recent study, for the first time, scientists geolocated and dated evidence of such boulder falls. They identified 245 fresh tracks created as boulders rolled, bounced, and slid down crater walls.

“For a long time, there was this belief that the Moon is geologically dead.…Our study shows that boulders with sizes ranging [from] tens to hundreds of meters and [with] weights in tons have moved from their places over time,” said Sivaprahasam Vijayan, the study’s lead author and an associate professor at the Physical Research Laboratory in Ahmedabad, India. “It is equally important to know how recent these boulder fall events are to understand the time periods when the geological agents were active.”

Tracking Boulder Falls

As lunar boulders bounce, they scoop up bright, unweathered subsurface material and bring it to the surface. As a result, fresh boulder fall tracks appear brighter than older ones.

“One can identify a boulder fall to be a recent one considering the boulder fall ejecta,” said Senthil Kumar Perumal, principal scientist with the Planetary Sciences Group at the National Geophysical Research Institute in Hyderabad, India, who was not involved in the new study.

The craters were found to be around 400,000 years old—which means the BFE tracks are more recent.

To identify relatively recent boulder tracks, Vijayan and his colleagues first manually searched thousands of images of the lunar surface between 40°S and 40°N. At these latitudes, the Sun makes the bright boulder tracks distinguishable from the rest of the lunar surface. Once they identified a track, the researchers studied corresponding images taken by NASA’s Lunar Reconnaissance Orbiter Narrow Angle Camera between 2009 and 2022.

Next, scientists estimated the age of the tracks by studying regions with both boulder fall ejecta (BFE) and distinct impact ejecta blankets. (Such blankets, nicknamed the “lunar equivalent of fossils,” have long been used to estimate the age of impact events.) The craters analyzed by Vijayan and his colleagues were found to be around 400,000 years old—which means the BFE tracks are more recent.

Finally, the scientists identified possible seismic faults or impact craters nearby that could have triggered the boulder falls.

Mapping the Moon

The new geological map of boulder falls, published in Icarus, highlights seismically active spots and fresh impact sites on the Moon. Researchers say these regions could be potential landing sites for future lunar missions focused on recent surface and subsurface activity.

The study authors plan to integrate artificial intelligence methods into the next iteration of their work, but ultimately, Vijayan said, “the next step is to more precisely determine whether the cause [of a fall] is endogenic or exogenic, which can be achieved by deploying additional seismometers in upcoming missions.”

Kumar concurred. “We need to have a large network of seismometers covering the entire [Moon] that monitors seismic activity continuously for several decades,” he said.

—Unnati Ashar, Science Writer

Citation: Ashar, U. (2025), Scientists track down fresh boulder falls on the Moon, Eos, 106, https://doi.org/10.1029/2025EO250314. Published on 27 August 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.

A new study has revealed that tiny organisms called snow algae are significantly contributing to the surface melting on Antarctic ice shelves. The discovery could have far-reaching implications for global sea level rise.

The Southern Ocean plays an important role in global climate and carbon cycling. Understanding carbon export in this region is critical for modeling Earth's changing climate and evaluating potential ocean-based climate interventions.