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In its annual forecast of the upcoming Atlantic Hurricane season, NOAA suggests the 2026 season has a 55% chance of being below normal, compared with a 35% chance of being near normal and just a 10% chance of being above normal.

The forecast, announced at a press conference at the NOAA Aircraft Operations Center in Lakeland, Fla., includes 8 to 14 named storms (with winds of at least 39 miles per hour), 3 to 6 of which will be hurricanes (with winds of at least 74 miles per hour). One to three of those are forecast to be major hurricanes (category 3 to 5 storms, with winds of at least 111 miles per hour).

NOAA forecasts that a below-average hurricane season is most likely in 2026, largely because of El Niño conditions. Credit: NOAA

A below-average number of hurricanes does not reduce the need for people to be prepared, NOAA representatives emphasized.

“Even though we’re expecting a below-average season in the Atlantic, it’s very important to understand that it only takes one.”

“Even though we’re expecting a below-average season in the Atlantic, it’s very important to understand that it only takes one,” said Under Secretary of Commerce for Oceans and Atmosphere and NOAA Administrator Neil Jacobs. “We have had category 5s make landfall in the past during below-average seasons.”

In contrast, NOAA is forecasting an above-average season in the Pacific, with a 70% likelihood of above-normal activity.

Matthew Rosencrans, lead hurricane forecaster with NOAA’s National Weather Service, noted that the Atlantic forecast does not yet contain information about potential hurricane landfalls, just the likelihood of their formation. National Weather Service Director Ken Graham said the potential for rapid intensification—when wind speed increases by at least 35 miles per hour over the course of 24 hours—makes early preparedness particularly important.

“Every category 5 that’s made landfall in this country was a tropical storm or less 3 days out,” he said. “So they rapidly intensified that quick. You think you might have a week on your timeline. The reality is you may only have days.”

“There will never be a ‘Hurricane Justa,’” he added. “There’s no such thing as just a category 1, just a tropical storm, just a category 2.…Even the smallest storm, if it’s slow enough and big enough, it’s going to be catastrophic flooding and storm surge.”

The Atlantic hurricane season runs from 1 June to 30 November. The NOAA forecast is in line with an Atlantic hurricane forecast issued 9 April by Colorado State University (CSU), which predicted 13 named storms and 6 hurricanes, including 2 major hurricanes. Similarly, a forecast released 22 April by North Carolina State University predicted 12 to 15 named storms, 6 to 9 hurricanes, and 2 to 3 major hurricanes.

All three forecasts are slightly below the average Atlantic hurricane numbers for 1991–2020: 14.4 named storms, 7.2 hurricanes, and 3.2 major hurricanes.

The World Meteorological Organization has released its list of 2026 Atlantic tropical cyclone names. Credit: NOAA El Niño

The forecast for below-average activity levels largely stems from El Niño, a climate pattern that increases vertical wind shear over the tropical Atlantic. Vertical wind shear is how much the speed and direction of wind change with altitude. When wind shear is too high, it can tear a hurricane apart before it forms.

“Wind shear is good for us, bad for the hurricanes,” said Phil Klotzbach, a hurricane forecaster at Colorado State University and lead author of the CSU report.

This year, researchers suggest El Niño could become the strongest in modern history, which could have ripple effects on global temperatures. At the NOAA press conference, Jacobs said that there is a 98% chance of El Niño conditions occurring later this season and an 80% chance that it will be moderate to strong. The forecasted strength of El Niño has only grown since CSU issued its forecast, Klotzbach said.

However, in addition to high wind shear, El Niño is also characterized by unusually warm waters in the Pacific. Klotzbach compared the warm waters of El Niño to loaded dice.

“If the waters are a little bit warmer, that will load the dice for the storm to get stronger.”

“To get to a hurricane, you need to have warm water,” he said. “You need to have a lot of other stuff as well, but if the waters are a little bit warmer, that will load the dice for the storm to get stronger.”

El Niño isn’t the only reason our oceans are warming.

At a press briefing hosted by Covering Climate Now prior to the NOAA press conference, Shel Winkley, a meteorologist at Climate Central, noted that about 90% of the excess heat caused by greenhouse gas emissions has gone into Earth’s oceans, as the planet tries to keep our atmosphere in balance.

“We’re not saying that climate change necessarily creates hurricanes,” Winkley said. “But it is supercharging them: More intense winds, heavier rain, bigger flooding. That’s the connection that we can confidently draw.”

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

Citation: Gardner, E. (2026), NOAA forecasts a below-average hurricane season, Eos, 107, https://doi.org/10.1029/2026EO260171. Published on 21 May 2026. Text © 2026. 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.

A new international study led by Lander Van Tricht (Vrije Universiteit Brussel, ETH Zürich), shows that glaciers in Central Asia experienced their most extreme mass-loss year on record in 2025, designated as the International Year of Glaciers Preservation by the United Nations, following an initiative from Tajikistan. The findings are published in the journal Environmental Research Letters.

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

At subduction zones, one tectonic plate dives beneath another, dragging rocks tens of kilometers into Earth’s interior where they are transformed by extreme pressures and temperatures. Some of these deeply buried rocks make it back to the surface, carrying a record of conditions along the plate boundary at depth. Geologists have long debated how these high-pressure rocks are exhumed and how they end up mixed into younger, lower-grade surrounding material.

Wang et al. [2026] address this question with detailed geologic mapping, Ar-Ar analyses, and U-Pb geochronology from subduction complex rocks on Cedros Island, offshore Baja California, Mexico. Their data show that high-pressure blocks yield cooling ages between 172 and 144 million years old, yet they are hosted in sedimentary rocks no older than about 92 million years. This age mismatch, combined with field evidence that the blocks are enveloped in sedimentary matrix rather than tectonically sheared into place, leads the authors to propose that the high-pressure rocks were exhumed to the surface, eroded, and recycled back into the subduction trench as sedimentary debris, potentially multiple times. The authors suggest that rapid exhumation was driven by extension within the forearc wedge. When plate convergence rates dropped abruptly, the wedge became gravitationally unstable and stretched along brittle-ductile shear zones, bringing deeply buried rocks to shallow crustal levels.

This polycyclic model is incompatible with alternative interpretations in which exotic blocks were mixed into their host matrix by viscous return flow within the subduction channel, because such models predict that blocks and their surrounding matrix should share similar thermal histories. Instead, the data require that blocks completed their journey to depth and back long before the surrounding sediments even entered the trench. The new understanding of subduction dynamics on Cedros Islands illuminates connections with the broader Franciscan Complex of California, where the origin of similar high-pressure blocks in younger matrix has been debated for decades. Together, these findings offer new perspectives on how subduction zones operate over long timescales and how their fragmentary rock record preserves fundamental evidence of the tectonic history of the continental margin. 

Citation: Wang, J. W., Kapp, P., Holder, R., He, J., Hernández-Uribe, D., & Worthington, J. (2026). Polycyclic metamorphism, exhumation, and recycling of subduction complex rocks, Cedros Island, Baja California. Tectonics, 45, e2025TC009340. https://doi.org/10.1029/2025TC009340

­­—Alexis Ault, Associate Editor, Tectonics

Text © 2026. The authors. CC BY-NC-ND 3.0
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Wind-driven waves on Earth move sediments and shape shorelines. They transport energy between the atmosphere and planetary surface and also mix bodies of liquid, affecting both chemistry and biology. On other worlds with surface liquids, either now or in the past, wind waves would likely perform the same function and so would play a key role in climate and astrobiological potential.

“They’re basically the interface between how the atmosphere communicates with the landscape, especially at the coast.”

New research went back to the fundamentals and explored the conditions that can generate waves on worlds with different physical properties and different liquids, such as Titan, Mars, and select exoplanets.

“Wind waves are really interesting phenomena,” said Una Schneck, a planetary science doctoral student at the Massachusetts Institute of Technology (MIT) in Cambridge. “They’re basically the interface between how the atmosphere communicates with the landscape, especially at the coast.”

The Physics of Waves

Past models of wind generation on other planets struggled because they tended to start from preexisting models of Earth waves. Those models were developed to describe waves in Earth’s specific combination of gravity, atmosphere, and surface liquid, namely, water, said Schneck, who led the new research. Such models were sometimes tailored to describe a particular location and season. Adapting those models for conditions on other worlds, including other liquids like methane and sulfuric acid, always seems to leave traces of Earth behind.

However, the physics of what creates wind-driven waves should be universal, Schneck said, so the team went back to the basics of wave generation. They developed a wave model that explores the relationship between a world’s bulk properties, like gravity and air density, and liquid properties, like surface tension, to determine the wind strength needed to produce a wave.

The team “created this model that went back to the basic physics of waves, instead of just trying to fit to known wave conditions,” said Taylor Perron, an MIT geomorphologist and planetary scientist and coauthor of the research.

The Curiosity rover landed in Gale Crater on Mars (left) and has since found evidence—wavy bedforms—that this former crater lake had waves. Titan’s northern hemisphere hosts a sprawling lake district (right). The shores of one of the moon’s largest bodies of liquid, Ligeia Mare, shows evidence of wave activity. Credit: Left: NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS; right: NASA/JPL-Caltech/ASI/USGS

The model showed that the threshold wind speed to generate a wave is lower for liquids with less surface tension, which makes it easier to change the liquid’s shape. Higher air density provides more force to push against a liquid’s surface, and lower gravity makes it easier for a wave to rise up—both factors allow a weaker wind to create a wave. The team published these results in the Journal of Geophysical Research: Planets in April.

Waves on Other Worlds

The team first tested their model on the only set of wind and wave data we have—Earth. They used 20 years of wave and weather data for Lake Superior. The model found, correctly, that it takes wind speeds of 2.2 meters per second to generate waves on the lake’s surface and accurately predicted the height of waves for different wind speeds.

They then used the model to predict wave conditions on other worlds. They started with Mars, which likely had ancient oceans and lakes. Winds of 1.2 meters per second would have created waves in the lake that filled Gale Crater millions of years ago. A wave in Gale Crater would have been taller than a wave on Earth produced by wind of the same strength owing to Mars’s lower gravity.

The story is similar on Titan, the largest moon of Saturn. Waves in Titan’s hydrocarbon lakes would swell with a mere 0.5 meter per second of wind and would rise higher than an Earth wave under similar wind conditions. But they would travel much more slowly than Earth waves and would be spaced farther apart.

“The paper represents our best theoretical understanding of how we expect for waves to behave in a variety of environments,” said Jason Barnes, a planetary scientist at the University of Idaho in Moscow who was not involved with this research. “The movie of Titan waves is particularly awesome—very slow moving for such large amplitudes! Although I don’t expect waves to get that high ever in Titan’s sluggish atmosphere, it’s fun to be able to visualize what they might look like if they did.”

“In theory, this is something that people could do.”

The team also explored wave-generating conditions on three Earth-sized exoplanets. The possible sulfuric acid lakes of the exo-Venus Kepler-1649 b would grow in winds of 5.3 meters per second but would grow to a height similar to that of Earth waves because of its Earth-like gravity. Water lakes on LHS 1140 b would grow in 2.7 meter winds, similar to those on Earth, but would not grow as high because of its higher gravity. And on 55 Cancri e, a lava world, it would take winds of 37 meters per second—a category 1 hurricane—to move tiny waves of molten rock.

“Would you be able to ever detect this? Is this a useful thing to think about, or is it just a fun thought experiment?” Schneck asked. “If the waves are tall enough, you should be able to detect a change in the polarization [of an exoplanet’s light curve] that would not only suggest that there is a liquid surface on that exoplanet, but that liquid surface has waves.…In theory, this is something that people could do.”

Will We See It? Not Soon

Right now, the only world known to have surface liquid other than Earth is Titan, but we don’t have the right observations of Titan to test the new model. The European Space Agency’s Huygens probe landed on the moon in 2005, but nowhere near the northern lake district. NASA’s Cassini mission (of which Huygens was a part) did not detect any waves but did observe a changing lake shore that hinted at wave activity.

It’s possible that Titan’s waves are seasonal and Cassini just didn’t have the right timing, Perron noted. Temperature changes during Saturn’s year could affect wind speeds and also the composition of Titan’s lakes, changing the conditions of wave generation.

Still, the wind speed needed to make a wave on Titan is so low that “it would be very surprising if waves never formed. It just may be difficult to catch them when they’re there,” he said.

“The best way to test this work would be to send a sea probe to float or motor on one of Titan’s big 3 seas.”

“The best way to test this work would be to send a sea probe to float or motor on one of Titan’s big 3 seas—Kraken Mare, Ligeia Mare, or Punga Mare,” Barnes said. “Such a ‘buoy’ probe would be able to simultaneously measure both the sea conditions and the wind conditions, allowing for a comprehensive test of the model.”

Alas, no such mission is in the works, and the upcoming Dragonfly mission won’t travel near any lakes to test this theory either. A future Titan orbiter might provide that information, while a current or future Mars rover might yet gather evidence showing how lakes worked in that planet’s past.

“The improved understanding of waves from this paper might help to constrain the possibilities for wave erosion at the margins of bodies of water…thereby helping us to probe into the past climates of Mars and Titan,” Barnes said.

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

Citation: Cartier, K. M. S. (2026), What winds whip up otherworldly waves?, Eos, 107, https://doi.org/10.1029/2026EO260165. Published on 21 May 2026. Text © 2026. 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.

Arsenic-contaminated groundwater affects more than 230 million people living in 108 countries. About 180 million of these people live in the Indian subcontinent (which includes Bangladesh, Nepal, and Pakistan, in addition to India) and Southeast Asia. The Indian state of Bihar, which borders Nepal, has several regions with extremely high levels of naturally occurring arsenic in their groundwater.

In Bihar, silt from the Himalayas containing arsenic and other heavy metals is routinely deposited in floodplains and seeps into the groundwater below. This phenomenon puts up to 21 million residents in Bihar at risk of consuming arsenic-contaminated water each day. Arsenic is a carcinogen that has also been linked to diabetes, pulmonary disease, cardiovascular disease, and infant mortality.

Though Bihar has close to 600 groundwater treatment units designed to filter out arsenic, a recent study of 98 units found that 90% of them were installed in parts of the state where groundwater arsenic levels were within the World Health Organization’s permissible limits (below 10 parts per billion)—which means almost all the communities that need these units the most still do not have access to them. The research was published in Groundwater for Sustainable Development.

“Some of the areas with these units had reported a higher prevalence of gallbladder cancer, which is associated with arsenic poisoning. But we found that it was the food that was the main source of arsenic exposure, not groundwater,” said Arun Kumar, a study author and senior scientist at Mahavir Cancer Sansthan & Research Centre in Patna, the state’s capital city. “In the last decade, we have observed drastic changes in groundwater arsenic levels in Bihar. Along with that, the cancer burden has also reduced in some parts of the state.”

In another city, Buxar, Kumar and his colleagues observed levels of arsenic of up to 1,900 parts per billion in the groundwater in 2015. But when the researchers retested that region’s water samples last year, the arsenic levels had gone down to 100–200 parts per billion.

“We hypothesize that because Bihar is prone to earthquakes, the seismic activity might have changed the properties of sediments and silt in groundwater. And perhaps, at some stage, those regions with the groundwater treatment units had experienced arsenic contamination,” added Kumar. “It is still a mystery to us” why the levels changed so drastically.

Ditching Groundwater for River Water

Kumar acknowledged that in the past few years, there has been a mushrooming of public and private groundwater arsenic treatment units in regions located within 10 kilometers (6.2 miles) of the Ganges River in Bihar. The majority of the 98 units included in the study were installed by the state government from 2016 onward. The researchers observed that privately owned units underwent regular maintenance, unlike many of the government-run units.

“Much of the previous large-scale groundwater testing conducted in Bihar was limited to the 6-mile stretch on either side of the Ganges River.”

The corresponding author of the study, Laura Richards, a professor of water resources and geochemistry at the University of Manchester, explained that regions close to the Ganges River may have been given higher priority mainly because they are situated along major roads and highways, making them easier to access than inland Bihar.

“Much of the previous large-scale groundwater testing conducted in Bihar was limited to the 6-mile stretch on either side of the Ganges River. The issue with that is that the regions selected for arsenic remediation units were likely based on nonrepresentative spatial sampling of the state, and those locations might not have necessarily covered all areas with arsenic contamination in the groundwater,” said Richards. “Arsenic distribution across the state is really quite heterogeneous.”

The researchers further found that in 10% of the locations where groundwater arsenic treatment units were installed by the state government, high levels of fluoride posed a greater public health risk than arsenic, suggesting that governmental policies were rolled out without site-specific water quality monitoring and testing.

“Alluvial or sand-rich aquifers are the main culprits of arsenic-contaminated water in Indian terrains.”

In addition to arsenic and fluoride, the groundwater in different parts of Bihar has high levels of manganese and iron. Currently, the state has more than 3,000 groundwater treatment units for arsenic, fluoride, and iron. However, Kumar said a better solution would be to look to other sources for drinking water and to ensure water treatment centers are properly maintained.

“People would be a lot safer if they stopped consuming groundwater altogether,” Kumar said. “This is why the state government has started treating and supplying water from the Ganges River to villages. They have already started doing it in two districts and plan on expanding the supply of river water.”

“Alluvial or sand-rich aquifers are the main culprits of arsenic-contaminated water in Indian terrains,” said M. Santosh, a professor at the China University of Geosciences in Beijing who was not involved in this study. “This study clearly shows how we can rectify remedial measures on a local level. We should encourage more such studies on how to tackle this problem.”

—Anuradha Varanasi, Science Writer

Citation: Varanasi, A. (2026), In Bihar, groundwater treatment units were installed in regions that didn’t need them, Eos, 107, https://doi.org/10.1029/2026EO260168. Published on 21 May 2026. Text © 2026. 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: AGU Advances

Most auroras appear in the “auroral oval” at high latitudes surrounding the magnetic poles. However, some can appear as a detached auroral arc from the auroral oval, at lower latitudes in mid-afternoon and connected to the oval only at a tip or two. Such a detached arc is believed to be linked to the “plasmaspheric plume,” the tongue-shaped extension of the plasmasphere during the recovery phase of a geomagnetic storm. (The plasmasphere is the torus-shaped region of cold, dense plasma above the low- and mid-latitude ionosphere.) The surface waves at the plume boundary cause it to ripple and modulate the various plasma waves in the plume.

Based on observations from multiple satellites and ground stations, Feng et al. [2026] find sawtooth-like undulations along the equatorward boundary of a detached auroral arc in the ultraviolet that was produced by energetic (>keV) electrons and accompanied by energetic (>10 keV) ions. The authors attribute the undulations to Electromagnetic Ion Cyclotron (EMIC) waves that are modulated by the surface waves and resonating with the energetic ions. The study unravels the fine-scale structures of detached auroral arcs and sheds important light on the dynamics underlying their formation.

Schematic illustration of the formation mechanism for the sawtooth-like undulations of a detached auroral arc. The surface waves modulate the Electromagnetic Ion Cyclotron (EMIC) waves in the plasmaspheric plume, causing the energetic ions to precipitate into the ionosphere and resulting in the formation of an afternoon detached auroral arc with sawtooth-like undulations. Credit: Feng et al. [2026], Figure 4

Citation: Feng, H., Wang, D., Hao, Y., Miyoshi, Y., Fu, H., Jun, C.-W., et al. (2026). First observation of sawtooth-like undulations in afternoon detached auroral arcs modulated by surface waves at the plasmaspheric plume boundary. AGU Advances, 7, e2025AV002234. https://doi.org/10.1029/2025AV002234

—Andrew Yau, Editor, AGU Advances

Text © 2026. The authors. CC BY-NC-ND 3.0
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New research from the University of St Andrews has precisely dated an eruption from Newberry Volcano and discovered that its ash spread more than 5,000 km across the globe, far further than previously thought for an eruption of its size.

Forecasts for the 2026 South Asia monsoon are for below average rainfall, but some of the most landslide prone areas of India may receive totals that are above average.

As usual, we are now starting to see the number of reported global fatal landslides increase as the northern hemisphere rainy season commences. In recent days, there have been fatal floods and landslides across several provinces of mainland China as well as landslides on the pilgrimage route to Kederath in northern India.

The global pattern is dominated by the South Asia (southwest / summer) monsoon, so it is interesting at this point to to consider the prospects for this year. The monsoon itself is expected to start in SW India next week, timing that is normal. It will then build over the following month or so.

The current forecast for the monsoon itself is that the total rainfall is likely to be below average. This is the WMO forecast:-

The WMO 2026 South Asia monsoon forecast from the WMO.

The map shows below average precipitation for much of South Asia. The IMD also forecasts below average rainfall.

Of course, in landslide terms we are interested mainly in SW India (Kerala), which has a below average forecast, and the mountainous areas of Pakistan, India, Nepal, Bhutan and Bangladesh. Much of this is also forecast to receive below average precipitation, but note the above average forecast for parts of northern India (Jammu and Kashmir, Himachal Pradesh) and NE India (Sikkim, Arunachal Pradesh). These are some of the most landslide-prone areas of India, suggesting that we may well see substantial landslide challenges in these areas.

The caveat of course is that monsoon-triggered landslides are sensitive to rainfall intensity as well as rainfall magnitude. A below average monsoon can bring intense rainfall events that trigged catastrophic landslides. Unfortunately, the forecasts cannot resolve this issue.

As an aside, the next few days in the European Alps will be interesting. We are about to see a few days of unusually high temperatures, which are likely to drive a wave of snowmelt and permafrost thawing. Given the time of year, this could well trigger extensive rockfall activity.

Unfortunately, by the time I get to Switzerland in nine days the weather is forecast to have reverted to cool drizzle!

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SummaryThe Fuyang Depression, located in the Southern North China Basin, exhibits promising gas generation potential and favorable hydrocarbon accumulation conditions. The hydrocarbon resource survey in this region has primarily involved active-source seismic exploration and drilling operations. Dense-array ambient noise imaging has proven to be an efficient and low-cost detection technique, providing background information on the reservoir accumulation conditions in sedimentary basins. This study utilizes continuous ambient noise records from two linear dense arrays in the Fuyang depression to build S-wave velocity structures and radial anisotropy models down to 3 km beneath the arrays. A modified cross-correlation beamforming method is applied to sub-arrays of the linear array to extract dispersion curves of the fundamental mode and first overtone Rayleigh waves, as well as fundamental mode Love waves, from the ambient noise. The phase-velocity cross sections of different surface wave modes beneath two linear arrays are thereby obtained directly without tomographic inversion. Depth inversion is then performed to derive SV- and SH-wave velocity structures and radial anisotropy for the two linear arrays. The sediment thickness of Quaternary and Neogene (Q+N) sedimentary sequences are delineated by the iso-velocity of S-wave at 1.3 km/s, calibrated with the borehole data. The widespread negative radial anisotropy layers are observed at the shallow subsurface, which are interpreted as the water-saturated open fractures. The S-wave velocity and radial anisotropy models provide valuable constraints for both seismic hazard assessment and hydrocarbon exploration within sedimentary basins.

NASA scientists have developed an artificial intelligence tool to take on a longstanding challenge in ocean waters. In a study recently published in the Earth and Space Science journal, researchers reported the tool was able to fuse data from multiple satellites and detect harmful algal blooms that occurred in western Florida and Southern California.

Scientists have uncovered new evidence that Earth's continents are continuously reworked deep beneath the surface, offering fresh insight into how continents have evolved over billions of years.

New research shows, for the first time, an unprecedented and significant warming of equatorial Atlantic upper intermediate waters during the mid- to late Holocene. The paper is published in the journal Geology.

Aerosols and clouds play a key role in Earth's climate budget. However, the extent to which they reflect solar energy depends heavily on how much water the particles can absorb. This so-called hygroscopicity has so far been represented in a simplified manner in climate models. An international research team led by the Leibniz Institute for Tropospheric Research (TROPOS) has now demonstrated through a global study that the models are not precise enough, particularly in urban regions.

body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news that impacts science and scientists today.

Human-driven climate change is driving the rise of sea levels, worsening flood conditions and threatening coastal communities around the world. Not only is sea level rising, but it’s rising faster every year. Understanding the degree to which different processes contribute to sea level, known as the sea level budget, can help scientists better predict where and how quickly sea level will rise under potential climate futures.

 
Related

•  Read the paper: Improved closure of the global mean sea level budget from observational advances since 1960
•  The Global Impact of Losing U.S. Sea Level Science
 

But for several decades there has been a “budget gap” between measurements of sea level change and the total estimated contributions from glaciers, polar ice, land storage, and oceans expanding as they heat up (thermospheric expansion). Research published today in Science Advances has helped close that budget gap by incorporating more recent sea level observations, reconciling measurements taken by different instruments, and including recent community estimates of sea level rise and its components.

The new analysis breaks down the drivers of sea level rise from 1960 to 2023. The team found that the largest contributor is heat-driven expansion of seawater, responsible for 43% of sea level rise since 1960. Melting ice contributed the next largest amount of sea level rise: 27% came from mountain glaciers, while 15% came from the Greenland Ice Sheet and 12% from the Antarctic Ice Sheet. Lastly, sea level rose 3% as land reduced its capacity to store water.

Since 1960, 43% of global sea level rise can be attributed to thermal expansion of water, just 3% to a reduction in land water storage, and the remainder from melting ice and glaciers. Credit: Zheng et al., Science Advances (2026)

“For years, there has been a frustrating gap between how much the oceans were observed to be rising and how much we could explain from the individual causes,” John Abraham, an engineer at the University of St. Thomas in St Paul, Minn., and a coauthor on the new research, said in a press release. “This work shows that, with better instruments, processes, and smarter analysis, this knowledge gap can be closed. We can explain sea level rise with greater confidence.”

The researchers also calculated the rate at which sea level has risen since 1960 and how each component factored in. They found that the rate of sea level rise has recently doubled: It was 2 millimeters per year averaged over 1960­–2023 and 4 millimeters per year averaged over just 2005–2023. The strongest driver of that doubling is ocean warming, responsible for 41% of the accelerating rate of sea level rise, followed by reduced land water storage (21%).

In the past, glacial melt was the largest contributor to sea level rise before it was overtaken by thermospheric ocean expansion overtook (left). The rate of sea level rise has been speeding up since about 1980, also driven by thermospheric ocean expansion (right). Credit: Zheng et al., Science Advances (2026)

This research demonstrates the importance of maintaining detailed records of sea level rise, collecting new measurements, and not backing away from global change research. With better data on which processes contribute to sea level rise and its acceleration, policymakers and local communities can create informed mitigation strategies that account for future rise.

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

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Sea level rise is a direct consequence of human-induced climate change: global warming. It is relentless and very hard to stop. It arises from human-induced warming and the consequential expansion of the ocean, plus the addition of more and more water from melting glaciers and ice sheets. It will continue long into the future.

Old oil and gas wells may continue to affect the environment long after they have stopped producing, with new field evidence showing that their leakage footprint can be broader and more persistent than surface methane measurements alone reveal. A study led by researchers at The Lyell Centre, Heriot-Watt University, examined persistent methane leakage from a legacy petroleum well in British Columbia, Canada. The team found that while methane emissions at the ground surface were concentrated in a relatively small area and varied through time, the leakage also left a wider detectable signature in the shallow subsurface and surrounding soils.

Roughly the size of Texas, the Karoo Basin of central western South Africa is brutally dry, sparsely populated, and known in part for its potentially “massive” hydrocarbon deposits.

South Africa, which consumes more energy than any other country in sub-Saharan Africa, has shown a growing interest in commercial fracking for shale gas and oil across the Karoo hinterland, with the country moving in late 2025 to lift a 13-year ban on shale gas exploration in the area.

However, a recent study from the University of Cape Town, published in Seismological Research Letters, cautioned that the Karoo might not be as seismologically calm as it appears, meaning fracking efforts could have the potential to induce earthquakes in the region.

A Swarm of Earthquakes

The researchers observed 66 earthquakes in this cluster between 2007 and 2022, ranging from 0.7 to 4.8 in magnitude.

The researchers investigated what they call a sudden swarm of earthquakes that occurred in the Leeu Gamka cluster, a region of the Karoo that was previously considered seismically stable. They observed 66 earthquakes in this cluster between 2007 and 2022, ranging from 0.7 to 4.8 in magnitude.

“The individual earthquakes here are very small,” said Alastair Sloan, a tectonics and structural geologist at the University of Cape Town.

Using ambient noise tomography, previous geophysical surveys, and information about the locations of past earthquakes, the researchers identified a critically stressed fault underlying the region. The fault appears to extend for at least 30 kilometers roughly west-northwest to east-northeast.

Looking at South Africa more generally, there are other places where there have been “fairly large” earthquakes with a similar orientation, Sloan said. He cited a series of large earthquakes in the early 20th century in a place called Koffiefontein, north of the study area, and the disastrous 1969 Tulbagh earthquake, west of the team’s study area.

Both of those earthquakes occurred in regions that are geologically similar to the Karoo, though they’re outside of the area being considered for shale gas exploration, Sloan said.

Fracking Risks?

In other parts of the globe, such as Oklahoma in the United States, processes related to oil and gas extraction have led to “induced earthquakes.” Most of these earthquakes have been triggered by wastewater disposal associated with oil production, not by fracking directly.

Researchers are unsure if industrial fluid injection in the Karoo, as is applied in shale gas fracking processes, could trigger significant seismic action in the region’s existing faults.

“Some locations which undergo shale gas development don’t see very much seismicity, and there is a catalog of things which need to be present for [seismicity] to be something that you would particularly worry about,” Sloan said.

For instance, if faults are only within the crystalline basement and therefore separated from the sedimentary layers where the fracking occurs, then it’s not likely they’ll be reactivated, because there’s no way for the fracking fluid to get down to the fault zone itself. Another factor, Sloan added, is that for significant earthquakes to occur, large faults that are already critically stressed need to be present in the region undergoing fracking.

The new study showed that both of these conditions may be met in the Karoo: Microseismicity does extend to the depths at which the carbonaceous shale is present. And this microseismicity is occurring on a reasonably extensive structure with a similar orientation to larger earthquakes that have already occurred in the region.

However, Sloan stressed, this isn’t a cause for immediate panic.

“I don’t want to be too alarmist; the size of the structure revealed by the microseismicity is not huge, and so we do not have evidence to expect an earthquake much larger than the damaging historical earthquakes that we have already seen in the wider region,” he said. “Globally, large earthquakes triggered by fracking (rather than associated deep wastewater exposure) are very rare, but the study suggests the necessary preconditions are present. And so the possibility needs to be considered and monitored carefully.”

Not Unique

Raymond Durrheim, a geoscientist and the South African Research Chair in Exploration, Earthquake and Mining Seismology at the University of the Witwatersrand, and who also examined the Ph.D. thesis on which the new study is based, said no area is perfectly seismically quiet.

“We know the way seismicity works in this whole area of southern Africa is that swarms occur,” he said. “They’ll last for years or even decades, and then they’ll die away. This is not a unique occurrence.”

This study was “useful,” though, Durrheim added, especially with the possibility of shale gas development in the Karoo. “It’s very important that we understand this because we know that when you inject fluid under high pressure, there’s always a chance you could trigger an earthquake,” he said, noting examples of fluid injection triggering earthquakes in places such as Canada. “It’s always a risk.”

To mitigate risks, Sloan suggested it would be useful to have a much denser network of seismometers within this region of South Africa.

—Ray Mwareya (@RMwareya), Science Writer

Citation: Mwareya, R. (2026), A swarm of earthquakes in South Africa’s Karoo Basin poses questions for oil and gas development, Eos, 107, https://doi.org/10.1029/2026EO260159. Published on 20 May 2026. Text © 2026. 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: Water Resources Research

Evapotranspiration is a critical link between water, energy, and carbon. Scientists need to understand it well to accurately predict weather, droughts, streamflows, and even carbon emissions.

Eddy covariance towers, which measure changes in the atmosphere, are one of the primary ways that scientists measure evapotranspiration in an ecosystem. But these measurements often have a problem with energy imbalance, in which the measured fluxes of sensible heat and latent heat add up to less than they should. (Sensible heat refers to measurable temperature changes occurring via conduction or convection, whereas latent heat refers to water in the atmosphere changing phases.) There’s something missing—up to 30% of the system’s energy—in the math, and that can cause problems for later uses of the measurements, from forecasts to climate policies.

Scientists can adjust evapotranspiration measurements to try to correct for this problem, but a commonly used method to do so assumes that the Bowen ratio, or the ratio between sensible and latent heat, remains constant. However, this assumption may be flawed.

Raghav and Kumar present a new way of tackling this old problem without making assumptions about the Bowen ratio. It’s based on water use efficiency, which is how effectively plants use water to produce biomass.

The method first uses a suite of data from an eddy covariance tower to estimate evapotranspiration and energy balance through time. Then it derives the underlying water use efficiency potential while accounting for the influence of atmospheric dryness. In general, for a given vegetation type, this potential underlying efficiency is considered to be relatively stable over a growing season. The statistically smoothed potential underlying water use efficiencies is then compared to reference values derived during periods when the energy balance is well constrained. The ratio of the two is then used to correct evapotranspiration.

The new method is more consistent and more tied to the physics of plant physiology than current methods when results from each are compared, the authors found.

The new method is appropriate for use with any eddy covariance tower location or dataset because the authors used data from more than 250 towers around the world, in a range of ecosystem and climate types, to build their approach. However, they add, it may be less reliable in environments where evaporation dominates transpiration, such as wetlands. Nevertheless, the authors say, this work marks an important advance in measuring evapotranspiration, with broad implications for water management, agriculture, and adapting to climate extremes and drought. (Water Resources Research, https://doi.org/10.1029/2025WR042766, 2026)

—Rebecca Dzombak (@rdzombak.bsky.social), Science Writer

Citation: Dzombak, R. (2026), Improving eddy tower evapotranspiration estimates, Eos, 107, https://doi.org/10.1029/2026EO260163. Published on 20 May 2026. Text © 2026. 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.

Tiny saltwater channels have a big influence on sea ice.

Sea ice typically includes pockets or channels of brine that allow salt water to flow vertically through the ice. When those channels align neatly, they need to make up only about 5% of the ice volume before the water can flow. But in more disordered, granular ice, salt water starts to flow only when the brine channels take up more space—roughly 10% of the ice volume, according to a new study published in Scientific Reports.

“If we’re trying to find predictive models about how these ice cores are responding under climate change, it’s going to be necessary to take into account these structural and microstructural conditions.”

This higher threshold could slow the drainage of surface melt ponds, as well as the transport of nutrients to microbial communities inside the ice.

“If we’re trying to find predictive models about how these ice cores are responding under climate change, it’s going to be necessary to take into account these structural and microstructural conditions,” said Stephen Ackley, a sea ice researcher at the University of Texas at San Antonio who was not involved in the study.

Disorderly Constructs

As seawater freezes, it forms a mixture of ice crystals and brine. In calm conditions, the ice slowly grows into long, parallel crystals separated by orderly brine channels. This columnar sea ice is common in the Arctic, and its properties have been widely used in sea ice models.

But in choppy waves or when the ice’s snow-covered surface floods and refreezes, new ice can’t grow into these ordered columns. Instead, it forms small, randomly oriented grains separated by more complex pores containing brine and gases. Called granular ice, this form is more common in Antarctica but is becoming increasingly prevalent in the Arctic as temperatures rise and ice cover thins.

“It’s the sequel we’ve been waiting decades for.”

In 1998, University of Utah mathematician Kenneth Golden established the first estimate of the point at which the brine channels are connected enough to allow water to flow in columnar ice, called the percolation threshold. The new work, also led by Golden, extends a similar analysis to granular sea ice.

“It’s the sequel we’ve been waiting decades for,” said Don Perovich, a sea ice researcher at Dartmouth who was not involved in the new work.

To quantify the percolation threshold for granular ice, Golden and his colleagues collected sea ice samples during two expeditions off the eastern coast of Antarctica in 2007 and 2012. They measured how quickly water moved through the brine channels in the ice. After the 2012 expedition, they also mapped the arrangement of ice crystals within the ice blocks to correlate those permeability measurements with the microscale structure of the ice.

Most climate models are based on the assumption that the microstructure of sea ice is organized into columns, like those in the image on the left. But new research shows that granular ice, as seen on the right, is growing more common in the Arctic, which could affect climate modeling. Credit: Golden et al., 2026, https://doi.org/10.1038/s41598-026-41706-w, CC BY-NC-ND 4.0

The finding that in granular ice, about twice as much of the ice volume needs to be brine for water to flow compared to columnar ice suggests that brine channels within granular ice are much less interconnected.

With the higher threshold, “you have to reassess all these models, anything that relies on fluid flow through sea ice,” if granular ice is present, said Golden. Granular ice will require warmer or saltier conditions to leave enough brine in the ice structure to meet the percolation threshold and allow water to flow vertically.

Researchers extracted blocks of ice in Antarctica with a chainsaw and poured dyed salt water on top. In this way, they observed how quickly the fluid descended through the ice. Credit: Kenneth Golden

For example, the new value could influence models of how meltwater ponds behave atop an underlying ice sheet. If meltwater ponds form above a base of granular sea ice, those ponds will require warmer temperatures before they start draining than melt ponds on columnar ice will.

If these melt ponds remain on the surface longer waiting for those warmer temperatures, they could lower the albedo, or reflectivity, of the ice sheet. That could cause the ice sheet to absorb more heat, leading to a feedback loop that could accelerate melting.

The higher percolation threshold could also affect algae that lives within the ice. Ice algae make up an important food source for krill and crustaceans, which in turn become food for fish, penguins, and whales. Algae rely on water flowing through the ice to deliver nutrients. Because granular ice requires warmer temperatures for that flow to start, it could affect the depth at which algae can live inside the ice, Golden said.

Percolation Consideration

Still, experts say more data are needed to establish percolation thresholds across both Arctic and Antarctic ice. The size of the grains in granular ice can vary substantially at different temperatures, under different formation conditions, and between the poles. Larger grains could lower the percolation threshold, allowing water to flow even when the ice contains much less than 10% brine by volume, said Sønke Maus, a scientist studying ice microstructure at the Norwegian University of Science and Technology who was not involved in the study.

“The data that we have at the moment for the granular sea ice is sparse,” Maus said. “You need a big campaign to collect such data.”

Golden said that in future work he also plans to develop models to compute the electromagnetic properties of both columnar and granular sea ice. Knowing these properties can help scientists determine the thickness and age of an ice sheet from satellite data.

—Skyler Ware (@skylerdware), Science Writer

Citation: Ware, S. (2026), Changes in sea ice microstructure could affect climate models, Eos, 107, https://doi.org/10.1029/2026EO260164. Published on 20 May 2026. Text © 2026. 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): Chubin Lin, Jiandong Chen, Huihui Wang, and Yangyang Fu

This Letter uncovers five distinct charge transport modes and their transitions in dual-energy electron beam diodes. We via first-principle particle-in-cell (PIC) simulations establish that the specific mode (e.g., space-charge oscillations) and the current transmitted characteristics are essentiall…

[Phys. Rev. E 113, L053203] Published Wed May 20, 2026