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А.П. Черняев

Обзор посвящён физическим основам ядерных технологий в медицине. Отмечены физические идеи, использованные при создании высокотехнологичных медицинских приборов и систем, а также ключевые моменты развития "ядерной медицины". Прослеживается история появления таких систем в России и мире, потребности здравоохранения, обсуждаются современные тенденции их развития. Описана система подготовки соответствующих кадров.

As Greenland's ice retreats, it's fueling tiny ocean organisms. To test why, scientists turned to a computer model from JPL and MIT that's been called a laboratory in itself.

Climate change warps the timing of natural processes. Scientists have evidence that flowers are blooming, trees are dropping their leaves, and animals are emerging from hibernation earlier than they did years prior.

“We’re seeing a trend towards an earlier onset.”

Now, there’s new evidence of another climate-related shift: California’s wildfire seasons are beginning as much as 46 days earlier than the typical onset 3 decades ago. The analysis, published in a paper in Science Advances, found that the trend was similar in almost all of California’s varied ecosystems.

The study defined wildfire season onset as the day when 5% of that season’s fires have occurred. “We’re seeing a trend towards an earlier onset,” said Gavin D. Madakumbura, a hydroclimatologist at the University of California, Los Angeles and lead author of the new study. “We wanted to understand what’s causing this.”

Previous work, including one landmark 2006 study, indicated that in some western U.S. forests, the wildfire season has both lengthened and started earlier.

To quantify the role of climate change in those trends, Madakumbura and his colleagues first analyzed U.S. Forest Service fire occurrence data and season start dates from 1992 to 2020 in California’s 13 ecoregions, from mountains in the north to deserts in the south. They found that since 1992, fire season has started earlier in all but one ecoregion (the Sonoran Basin and Range). The Cascades ecoregion shifted the most, with its 2020 onset occurring 46 days earlier than in 1992.

“The fact that they can see [the shift] across a broad array of ecosystems, most of them statistically significant, is noteworthy,” said LeRoy Westerling, a climate scientist at the University of California, Merced who was the lead author of the 2006 study that first indicated the shift. Westerling was not involved in the new study.

Though the shift in onset timing has been suspected for years, its magnitude is “much larger” than anticipated and “truly surprising,” wrote Virginia Iglesias, a climate scientist at the University of Colorado Boulder who was not involved in the new study, in an email.

Northern California ecoregions showed stronger trends than southern ecoregions, with the Eastern Cascades, Cascades, Central California Foothills, and Coastal Mountains showing the most significant changes. Madakumbura said the north-south difference exists because northern ecoregions’ fire seasons are more sensitive to changes in winter snowpack, which has also dwindled as the climate warms.

Climate Change’s Role

The team then evaluated the role of climate change as a driver of each ecoregion’s fire season start dates.

For each ecoregion, they determined how strongly climate-related drivers, such as how dry fuels were, influenced fire season start date compared with drivers that were not directly related to climate change, such as vegetation type. Then they compared changes observed for each of those drivers through time.

“The calendar-based boundaries we’ve long relied on for fire preparedness may no longer hold.”

The result suggested that although natural variability and severe droughts in the mid-2010s contributed to earlier fire seasons, climate change was a major driver of the earlier season in 11 of the 13 ecoregions.

“The climate, and the aridity of fuel, is the main controlling factor,” Madakumbura said.

“The paper presents compelling evidence that anthropogenic climate change is a dominant and quantifiable driver of the earlier wildfire season onset,” Iglesias wrote. “The logic is clear and the conclusions are well supported.”

As the climate continues to warm, fire seasons in California will likely start even earlier, the authors wrote. Knowing that fire seasons are trending earlier can help emergency managers prepare for longer fire seasons that burn more area, Madakumbura said.

“An earlier start to the season just taxes all these resources that much earlier,” Westerling said. “It’s the same people, the same equipment, and the same budgets that are under stress.” Fire season in California is extending later into the fall as well, he said, creating a much longer period when communities need to stay prepared for fires.

The asymmetry between northern and southern trends “highlights the need for regionally tailored fire management and climate adaptation strategies,” Iglesias wrote.

“The calendar-based boundaries we’ve long relied on for fire preparedness may no longer hold.”

—Grace van Deelen (@gvd.bsky.social), Staff Writer

Citation: van Deelen, G. (2025), California’s getting an earlier start to wildfire season, Eos, 106, https://doi.org/10.1029/2025EO250297. Published on 6 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.

Analysis of ocean sediments has surfaced geochemical clues in line with the possibility that an encounter with a disintegrating comet 12,800 years ago in the Northern Hemisphere triggered rapid cooling of Earth's air and ocean. Christopher Moore of the University of South Carolina, U.S., and colleagues present these findings in the journal PLOS One on August 6, 2025.

Researchers are calling for a more reliable approach to understanding water-related hazards by explicitly accounting for uncertainty in their predictions, arguing this could improve how communities prepare for the risk of floods, droughts, and river-related erosion.

When an enormous 8.8 magnitude earthquake struck near Russia's Kamchatka Peninsula, the impact reached far beyond its epicenter. In the passing hours, tsunami alerts were issued by several nations with coastlines along the Pacific Ocean's Ring of Fire, prompting evacuations and escalating emergency response efforts from Japan to Hawaii and along the U.S. West Coast. Due to a number of geological factors, this disaster did not result in significant damage or loss of life. That said, it served as a powerful reminder that in the face of rapidly moving natural hazards, the primary defense is time, and the systems that give us a chance to act before time runs out.

A recent study in Nature Geoscience offers important new insights into the hidden role of ancient groundwater beneath the ocean floor—and how it may have interacted with ice sheets and rising sea levels during past climate changes.

Source: Global Biogeochemical Cycles

Human activity is shifting the type of nitrogen flowing out of Arctic rivers and into the Arctic Ocean, a new publication shows. The amount of organic nitrogen, which is derived from living things, is going up. Meanwhile, the amount of inorganic nitrogen, which is produced from nitrogen in the air through chemical reactions, is going down.

Ruyle et al. sampled water from sites at six Arctic rivers: the Kolyma, Lena, Ob, and Yenisey in Russia; the Mackenzie in Canada; and the Yukon in the United States. Together, these watersheds cover about two thirds of the land area that drains into the Arctic Ocean. From 2003 to 2023, researchers collected samples from the rivers five to six times per year and measured the abundance of various forms of nitrogen. In four of the six rivers (Lena, Ob, Yenisey, Mackenzie), the ratio of dissolved organic nitrogen to total nitrogen (i.e., the sum of organic and inorganic nitrogen) increased significantly during that period at a rate between 1% and 2% per year.

The team applied newly developed models to these measurements to identify environmental and climate conditions associated with changes in nitrogen composition. The amount of water flowing through rivers, the extent to which surrounding permafrost has thawed, and the prevalence of burned landscape are all key drivers of the shift from inorganic to organic nitrogen, they found. Climate change is intensifying all of these conditions, so the trend is likely to continue.

Photosynthetic organisms such as algae and cyanobacteria typically use inorganic nitrogen to fuel their growth, whereas organisms that eat other living things can use organic nitrogen. The microbes that cause harmful algae blooms are typically photosynthetic.

So in the coming years, a decrease in inorganic nitrogen in these rivers could lead to fewer harmful blooms in coastal regions where river inputs are most important. However, the overall effects of a shift from inorganic to organic nitrogen are not completely understood, and the authors suggest the shifts should be the subject of future research. (Global Biogeochemical Cycles, https://doi.org/10.1029/2025GB008639, 2025)

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

Citation: Sidik, S. M. (2025), Arctic rivers trade inorganic nitrogen for organic, Eos, 106, https://doi.org/10.1029/2025EO250292. Published on 6 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.

Smelting metals and burning coal vaporize small amounts of iron. Some of this iron wafts out of East Asia and into the North Pacific Ocean, where it supercharges phytoplankton growth, a new study found.

The study, published in the Proceedings of the National Academy of Sciences of the United States of America, used isotope analysis to estimate that around 39% of the iron in seawater sampled from the North Pacific during the springs of 2016, 2017, and 2019 came from human activities. This added iron is helping phytoplankton consume marine nitrogen faster, causing a long-term northward shift in a North Pacific algal bloom.

“The nitrogen is like a paycheck that they get every year, and when they have more iron, they spend through it faster.”

“The nitrogen is like a paycheck that they get every year, and when they have more iron, they spend through it faster,” said the study’s first author, Nick Hawco, a marine geochemist at the University of Hawaiʻi at Mānoa.

Strong winds churn the waters of the North Pacific every winter, lifting nitrogen and other nutrients to the surface. As ocean currents carry the nutrients south toward a region of mixing gyres called the North Pacific Transition Zone, they fuel a phytoplankton bloom that extends from California to Japan. Tuna, humpback whales, and other sea creatures come to feast on the animals supported by the phytoplankton.

Over the spring and summer, the phytoplankton exhaust the nutrients brought south by currents. This depletion causes the southern extent of the bloom, called the transition zone chlorophyll front, to shift north each year, toward the nutrient-rich subarctic.

Have Iron, Will Travel

Hawco and his colleagues studied the metabolisms of phytoplankton captured from the North Pacific and found signs of iron deficiency. Iron is a limiting factor for phytoplankton growth in the region, the authors argued.

Though desert dust carried long distances by winds historically brought iron to the North Pacific, previous research has shown that industrial activities in East Asia—especially burning coal and melting metals—are a new and growing source of iron.

Between 1998 and 2022, steel production in China, Japan, South Korea, and Taiwan quadrupled, and coal use more than tripled, according to data from the Global Carbon Project and the World Steel Association. During the same period, the southern edge of the bloom in April shifted north by about 325 miles (520 kilometers), according to satellite measurements of chlorophyll.

“This extra iron is leading to the nitrogen being drawn down earlier in the season, and it’s pushing these waters that eventually become nitrogen limited further to the north.”

In the northern parts of the phytoplankton bloom, chlorophyll concentrations increased, suggesting that the added iron is driving a more intense bloom, according to the authors. As a consequence, the southern edge of the bloom does not reach as far south during the spring, Hawco said. The nutrients that used to fuel it are likely being consumed by the more intense bloom up north, he said.

“This extra iron is leading to the nitrogen being drawn down earlier in the season, and it’s pushing these waters that eventually become nitrogen limited further to the north,” said Peter Sedwick, a chemical oceanographer at Old Dominion University in Virginia who was not involved in the study.

Northward movement of the bloom could have wide-ranging effects. Because the ecosystem supports abundant marine life, many anglers from Hawaii travel there to fish, Hawco said. As it shifts north, that trip is becoming longer and more expensive, he said.

Chlorophyll concentrations, a proxy for phytoplankton, shift seasonally. Credit: NASA Earth Observatory

In addition, research suggests that climate change will reduce the amount of nutrients brought from the depths to the surface of the North Pacific. That will reduce the supply of nutrients brought south by currents, causing the southern extent of the bloom to move even farther north, Hawco and his colleagues said. Iron emissions and climate change are having synergistic effects on the transition zone chlorophyll front, they concluded.

Further research is needed to understand the impacts of this extra metal. The phytoplankton bloom sucks up carbon and helps maintain the balance of carbon dioxide between the ocean and the atmosphere, Sedwick said. Any change to the ecosystem could alter that balance, he added.

—Mark DeGraff (@markr4nger.bsky.social), Science Writer

Citation: DeGraff, M. (2025), Iron emissions are shifting a North Pacific plankton bloom, Eos, 106, https://doi.org/10.1029/2025EO250286. Published on 6 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.

Source: Journal of Geophysical Research: Biogeosciences

This is an authorized translation of an Eos article. 本文是Eos文章的授权翻译。

当地震引起滑坡、泥石流或侵蚀时，它可以通过引入颗粒更大的沉积物来改变附近湖泊的组成，导致沉积物堆积更快，并影响碳封存。堆积在湖底的沉积物就像一个历史档案，记录了湖泊的生物、物理和化学变化，以及它们如何影响硅藻（微小的玻璃状藻类）等微生物。然而，人们对于地震引发的突然扰动会如何影响湖泊生态系统知之甚少。

Xue等人观察了喜马拉雅地区措普湖（Lake Tsopu）的长期变化。1900年至2017年期间，措普湖周围200公里半径内发生了63次5级以上地震。这里的高海拔、高寒气候和低人类活动使得措普湖成为研究这些地震引起的微生物和地球化学变化的理想场所。

2017年，研究人员从措普湖中心水深14米处采集了一个45厘米长的沉积物岩芯。然后，他们将岩芯分成41个1厘米长的样本进行分析。研究人员发现了1900年至1923年间发生的两次大地震（7.09级和7级）的标志。一个标志是深度为28到35厘米处的砂粒含量增加，另一个标志是，与较浅处（1到23厘米）相比，深度较深处（28到35厘米）的颗粒大小中位数增加。

研究人员按照两个时间段对沉积物岩芯进行划分，第一阶段包含地震事件（1886-1917），第二阶段包括地震后的几十年（1923-2017）。他们注意到，地震后硅藻数量急剧减少，这可能是因为沉积物和氮的增加。在第一阶段，硅藻的多样性暂时增加，而后在第二阶段减少，这可能是由于沉积物的横向运输。此外，底栖物种在地震后减少，而漂浮物种则激增。

根据措普湖的研究结果，研究人员估计，全球大约有15000个湖泊——约占全球湖泊数的1.1%和湖泊面积的1.7%——在大地震之后经历了类似的剧烈变化，改变了水面以下以及周围景观的生态系统平衡。(Journal of Geophysical Research: Biogeosciences, https://doi.org/10.1029/2024JG008723, 2025)

—科学撰稿人Rebecca Owen (@beccapox.bsky.social)

Read this article on WeChat. 在微信上阅读本文。

This translation was made by Wiley. 本文翻译由Wiley提供。

Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Editors’ Vox is a blog from AGU’s Publications Department.

Some may think writing or editing a scholarly book is something scientists only do later in their careers after several decades of research, teaching, and other professional experience. On the contrary, two scientists who completed book projects with AGU as early-career researchers found the years right after earning their PhD to be the ideal time to pursue this opportunity. In the first installment of three career-focused articles, these scientists reflect on the positive outcomes the experience had on their professional development.

Matthew Currell co-edited the book Threats to Springs in a Changing World: Science and Policies for Protection, which explores the causes of spring degradation and strategies to safeguard them. Rebekah Esmaili authored Earth Observation Using Python: A Practical Programming Guide, a book on basic Python programming to create visualizations from satellite data sets. We asked Currell and Esmaili about why they chose to complete book projects as early-career researchers, the unique strengths early-career researchers bring to such endeavors, and the impacts their books had on their careers.

How would you describe the early-career researcher stage in a scientist’s career?

MC: The first decade of a researcher’s career is a time of great discovery, when the world opens up in front of you. This period can also have its challenges and be quite daunting. It is when responsibility to identify the big research questions of our time, design quality research projects, and start supervising other researchers in training is handed to you all at once. Staying true to the motivations and passion that led you into research in the first place—and making sure you take time to keep listening and learning from those with experience, insight, and knowledge in your field—are key to success. 

Even though early-career contributions differ from those of senior researchers, they are still incredibly important for the community to continue thriving.

RE: Early-career researchers are the fresh growth on the knowledge tree, branching out in new directions. They have novel ideas and the enthusiasm to share them, and are quick to learn and adopt new concepts and technologies, so they help the tree gather nutrients and grow. It’s an exciting time to work alongside senior researchers who are astoundingly knowledgeable. A challenge is that early-career researchers may struggle to find their voice; but even though early-career contributions differ from those of senior researchers, they are still incredibly important for the community to continue thriving.

Why did you decide to write or edit a book?

RE: I did not plan on writing a book until I presented a scientific workshop, “Python for Earth Observation,” at an AGU annual meeting. I was inspired to simultaneously teach Python skills while showcasing the visually stunning, publicly available imagery produced by Earth satellites. I initially planned to offer the workshop only once, but the participants’ feedback showed strong interest in the material. Since then, I have presented the workshop every year that I could attend AGU. I decided to write the book to amplify my workshops and to make the content accessible to those unable to travel to conferences. Writing a book appealed to me because books can be widely shared and referenced, and can provide greater detail than is possible during a 4-hour workshop.

MC: The idea for the book first came in an email from my co-editor on the project, Dr. Brian Katz. As soon as I saw the suggested topic on freshwater springs, I was hooked and quickly became determined to make the book a reality. Having spent time with many people, including Aboriginal Traditional Owners from my home country, Australia, I knew how important springs are as a source of water but also a source of life, culture, and connection to the land. I also knew firsthand how many springs were under threat, and how urgent the task was of promoting good science and good policy in the way we manage these springs.

What impact did your book have on your career?

The biggest value and benefit from the book was all the fantastic people and relationships that it helped to build.

MC: I think the biggest value and benefit from the book was all the fantastic people and relationships that it helped to build. For example, the chapter on springs in the Great Artesian Basin at Kati Thanda was very well received by the Arabana Rangers, who are the custodians of the springs and the lands of northern South Australia. This relationship has grown, and now the Arabana Rangers are set to come and present their story of the springs at the upcoming International Association of Hydrogeologists Congress, where I’m organizing the program through the conference technical committee. 

RE: Writing a book was a huge project, but doing so helped me master the subject matter, as I had to think deeply about the content and consider how digestible it would be to a new programmer. It also gave me the confidence to take on challenges at work. For example, learning to break down tasks into smaller pieces during the publication process empowered me to apply for larger grants and projects. Project management at work felt less overwhelming because after writing a book, I had experience writing proposals, developing milestones, creating reasonable schedules, collaborating with multiple partners, and delegating chapter reviews.

What were the benefits of completing a book as an early-career researcher, as opposed to doing so at another point in your career? 

RE: Early-career scientists can have more empathy for the reader because they have more recent experiences learning new concepts built upon knowledge they have not mastered yet. My awareness of the audience was a strength, and I ended up writing the book I wished I had when I was getting started. I was sensitive to using dense, discipline-specific language that was challenging to understand. Instead, I made a conscious choice to use clear, kind, and encouraging language. If I had written the book later in my career, it might have resembled a traditional textbook, many of which make assumptions about what the reader should already know.

MC: The book helped me to get in touch with many fantastic people around the world working in freshwater springs research, and I had the chance to learn a huge amount from editing the different chapters that present case studies from around the world. These relationships have inspired new ideas and collaborations, and the circle keeps growing —for example, through the global network of researchers called “the Fellowship of the Spring.” Finally, completing a book and seeing it published also brought a huge sense of accomplishment.

—Matthew Currell (m.currell@griffith.edu.au, 0000-0003-0210-800X), Griffith University, Australia; and Rebekah Esmaili (rebekah.esmaili@gmail.com, 0000-0002-3575-8597), Atmospheric Scientist, United States

This post is the first in a set of three. Stay tuned for posts about leading a book project in the mid-career stage and as an experienced researcher.

Citation: Currell, M., and R. Esmaili (2025), Early-career book publishing: growing roots as scholars, Eos, 106, https://doi.org/10.1029/2025EO255025. Published on 6 August 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.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Planets

Boulders are ubiquitous on the lunar surface. However, the lifetime of boulders on the surface is relatively short, lasting no longer than a few hundred million years, as the boulders are broken down and eroded in the space environment. Therefore, the presence of rocks indicates relatively recent activity. The rock abundance and size distribution can provide information on the evolution of the lunar surface and the development of the dust and rock fragments that comprise the regolith.

Rock abundance maps have been generated in the past by fitting models to thermal data. However, the rock abundance derived from the images provides greater detail about the size distribution of the rocks and their locations. Manually identifying and measuring the sizes of boulders on the lunar surface using images from orbiting spacecraft is very time consuming and laborious. As a result, a global map of boulders identified from images requires automated methods.

Aussel et al. [2025] use a deep learning algorithm to identify and measure the size of approximately 94 million boulders, providing the first near-global map of boulders larger than 4.5 meters across the lunar surface between 60° S and 60° N. The data show boulders are concentrated around impact craters and steep slopes. Distinct differences occur between the maria and highlands, with maria having higher densities of boulders, but with smaller average sizes. However, a significant variation in abundances is observed on different mare units suggesting differences in the properties of the volcanic rocks. The study also quantifies the size distribution of boulders and how the largest boulder sizes ejected by impact craters scale with crater size. While this study finds general agreement with the thermally derived maps, local differences are observed likely due to the sensitivity of the techniques to different rock sizes and geologic settings.

The study highlights how cutting-edge machine learning techniques can push the boundaries of what can be done in planetary science and can open up new avenues in research that previously were intractable. The end result is a rich dataset that has the potential to yield continued insights into the lunar environment, and the processes that shape that environment, as the research community studies the data further.  

Citation: Aussel, B., Rüsch, O., Gundlach, B., Bickel, V. T., Kruk, S., & Sefton-Nash, E. (2025). Global lunar boulder map from LRO NAC optical images using deep learning: Implications for regolith and protolith. Journal of Geophysical Research: Planets, 130, e2025JE008981. https://doi.org/10.1029/2025JE008981

—Jean-Pierre Williams, Editor, JGR: Planets

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): Iván Calvo, José Luis Velasco, Per Helander, and Félix I. Parra

Until now, quasi-isodynamic magnetic fields have been the only known stellarator configurations that, at low collisionality, give small radial neoclassical transport and zero bootstrap current for arbitrary plasma profiles, the latter facilitating control of the magnetic configuration. The recently …

[Phys. Rev. E 112, L023201] Published Wed Aug 06, 2025

A possible cause of the 5 August 2025 landslide is the failure of a large body of glacial material high in the valley above the village.

The imagery that is emerging after the 5 August 2025 debris flow in Dharali (Tharali), in Uttarakhand, northern India make very somber viewing. Melaine Le Roy posted this comparison to BlueSky, which illustrates the scale of the flow that has struck the village:-

BEFORE/AFTER the Dharali village debris flow today!

SummaryTransform faults are one of the major tectonic plate boundaries offsetting the global mid-oceanic ridge system. The topographic features within these transform faults provide crucial evidence for tectono-magmatic processes and crustal accretion in transform fault zones. These interesting features include median ridges, which are major bathymetric anomalies found within both slow-slipping and fast-slipping transform faults, often associated with exposures of ultramafic rocks on the seafloor. To explain the origin of median ridges, previous studies have invoked multiple processes such as serpentinite diapirism, thermal uplift at ridge-transform intersections, or transpressive uplift induced by global plate reorganization, without any knowledge of the seismic structure. Here, we present results from 2D travel time tomography of downward-continued multi-channel seismic data along and across an ∼80 km long median ridge that lies within the eastern end of the slow-slipping (∼3.4 cm/yr) Chain transform fault in the equatorial Atlantic Ocean. The data were acquired during the 2018 ILAB-SPARC survey using a 6-km long streamer. Our high-resolution P-wave velocity model of the median ridge shows distinct high and low velocities ranging from 2.5 to 5 km/s within 500 m below the seafloor, on either side of the presently active strike-slip fault trace that cuts through the ridge. The low velocity on the eastern side of the ridge could be due to the presence of highly fractured basalt (with porosity in the range of 28 to 36 per cent) due to transform fault motion, whereas the high velocity on the western flank could be due to the presence of gabbro or highly serpentinised peridotite. The basaltic origin of the median ridge is supported by the observation of a seismic triplication event, which we call the T-event. The depth at which the T-event maps is shallow (200–500 m below seafloor) in high-velocity regions and deeper (600–1400 m) in low-velocity regions. We also find that the currently active strike-slip fault has been active since at least 0.26 Ma and has sliced the ridge. We image low-velocity pockets at the northern and southern limits of the median ridge that could represent the expression of the currently less active strike-slip faults.

For a wide variety of earthquake scenarios in Alaska, an earthquake early warning (EEW) system could provide at least 10 seconds of warning time for hazardous shaking, according to a new report.

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.

For the past month, the Trump administration, via NASA’s Acting Administrator Sean Duffy, has been directing NASA employees to implement workforce adjustments and plan for the shutdown of dozens of missions and programs slated for cuts under in the President’s Budget Request to NASA. Doing so ahead of a Congressionally-approved budget for fiscal year 2026 (FY26) is tantamount to illegal impoundment of federal funds appropriated for the current fiscal year (FY25), according to an 18 July letter to Duffy signed by 64 members of Congress.

Now, despite warnings that their actions are illegal, NPR reports that Duffy and other senior NASA officials have continued to secretly direct NASA employees to draw up plans to end at least two major satellite missions specifically designed to monitor global carbon dioxide. Orbiting Carbon Observatory (OCO)-2, a free-orbiting satellite, and OCO-3, which is attached to the International Space Station, are slated for defunding in the 2026 President’s Budget Request (PBR).

David Crisp, a retired NASA atmospheric physicist who was the principal investigator of the original OCO mission and was OCO-2’s science team leader, told NPR that he was contacted by several NASA employees who asked him pointed questions about the satellites that added up to mission termination plans.

 
Related

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•  Read the letter from lawmakers to Acting Administrator Duffy
•  Get Involved: AGU Science Policy Action Center

“What I have heard is direct communications from people who were making those plans, who weren’t allowed to tell me that that’s what they were told to do. But they were allowed to ask me questions,” Crisp said. “They were asking me very sharp questions. The only thing that would have motivated those questions was [that] somebody told them to come up with a termination plan.” (Crisp is also a Fellow of AGU, which publishes Eos.)

Two current NASA employees confirmed to NPR that NASA leaders were told to make plans to terminate projects that would lose funding should Trump’s PBR be enacted. The employees, who requested anonymity, also told NPR that agency leadership is seeking private backers to keep the OCO satellites running should they lose federal funding.

The Orbiting Carbon Observatories were designed specifically to monitor and map the global carbon budget, and they have provided valuable data about the drivers of climate change. The satellites also exhibited a surprising ability: monitoring plant growth. The mission has provided maps of photosynthesis around the world that have proved valuable tools for farmers and the agricultural industry, including the U.S. Department of Agriculture. Experts warn that farmers could lose access to those tools if the satellites are privatized or decommissioned.

“Just from an economic standpoint, it makes no economic sense to terminate NASA missions that are returning incredibly valuable data,” Crisp said.

Growing plants emit a form of light detectable by OCO-2 and OCO-3. Here, red, pink, and white indicate areas of growth and gray indicates areas of little growth. Credit: NASA’s Scientific Visualization Studio Budgets Pending

Both the Senate and House appropriations committees recently released FY26 funding bills for NASA for consideration by Congress. The House does seek to cut NASA’s overall budget, though far less than requested by the Trump administration. The House’s draft bill does not break down appropriations by NASA’s subdivisions or programs, so there is little information about whether OCO would be defunded should the House’s budget be adopted.

The draft budget from the Senate appropriations committee, which also doesn’t mention OCO by name, nonetheless offers more details about what funding they would approve. Under that budget framework, NASA would receive $24.9 billion total (up from $24.8 billion in FY25). NASA’s Science Mission Directorate would lose a modest amount of funding ($7.3 billion, down from $7.5 billion), and the Earth Science division, which operates OCO, would also lose some funds ($2.17 billion, down from $2.2 billion).

The Senate committee’s more detailed explanation may shed light on its plans for OCO and other Earth-observing missions:

• “The Committee rejects the mission terminations proposed in the fiscal year 2026 budget request for Earth Science, Planetary Science, Astrophysics, and Heliophysics.” That’s about as explicit as they can be.
• “In advancing the U.S. national interest, NASA should seek, to the extent practicable, to retain public ownership of technologies, scientific data, and discoveries made using public funds.” This directive runs counter to NASA’s plans to privatize satellites that Trump seeks to defund.
• “Earth Science missions could help to understand the efficacy of carbon dioxide removal proposals, including to track carbon stocks and carbon cycling in aboveground biomass and coastal marine ecosystems.” The committee recognizes that Earth-observing satellites are important to the future of the planet.

Neither the House nor Senate appropriations bills have been taken up by either chamber of Congress. The bills still need to be passed by their respective chambers, reconciled into a single budget bill that passes both chambers of Congress, and signed into law by the president before FY25 ends on 30 September.

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

Correction 5 August 2025: David Crisp’s position with NASA and his association with AGU have been corrected.

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A previously unexploited source of information is now throwing new light on Earth's climate during the age of dinosaurs. Fossilized dinosaur teeth show that concentrations of carbon dioxide in the atmosphere during the Mesozoic Era, i.e., 252 to 66 million years ago, were far higher than they are today. This has been determined by researchers at the universities in Göttingen, Mainz, and Bochum following the analysis of oxygen isotopes in the dental enamel of dinosaur teeth.

A massive landslide has destroyed a remote Himalayan village. Fifty or more people may have died.

Astonishing and terrifying footage has appeared today of a dreadful debris flow that struck the village of Tharali (also called Dharali in some places) in Uttarakhand today. The video has been widely shared on social media. This is a version on Youtube (the footage starts at about 6 seconds):-

There is confusion about the location of this event, but i believe it is at: [31.0406, 78.7811]. This is a Google Earth view of the village in question:-

Google Earth view of the site of the 5 August 2025 debris flow at Tharali in northern India.

News reports indicate that four people are known to have died and that about 50 people are missing, although there will be huge uncertainty in those numbers.

Whilst this event has been variously described as a flood or a flash flood, it is without doubt a debris flow (i.e. a landslide). The trigger appears to have been a cloudburst event. The exact mechanism to generate the debris flow is unclear at present, but the valley above Tharali is steep and rugged:-

Google Earth view of the valley that generated the 5 August 2025 debris flow at Tharali in northern India.

Note the marker that delineates Tharali – it is the valley above the village that has generated the flow. Possible causes could be multiple landslides that have combined to create a channelised debris flow, a single large landslide that transitioned into the flow, or a valley blocking landslide that collapsed. We won’t know until satellite or aerial imagery is available.

Rescue operations are going to be hampered by the blockage of other roads by the same rainfall event, the remote location and the low survivability of such debris flows.

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