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Geoengineering could protect the Amazon rainforest from climate change, new research shows. Stratospheric aerosol injection (SAI) aims to artificially cool Earth by increasing the reflection of incoming solar radiation, thereby offsetting warming caused by anthropogenic greenhouse gases. SAI is designed to mimic explosive volcanic eruptions by injecting aerosols into the stratosphere.

Planting more trees will decelerate climate change only if those trees are placed in optimal locations—primarily the tropics and subtropics—suggests new research published in Communications Earth and Environment. However, planting trees in locations like Alaska, Siberia, and large parts of the United States could actually lead to warming, said lead author and doctoral student at ETH Zurich Nora Fahrenbach.

Much of the current thinking in nature-based solutions, Fahrenbach said, is based on the idea that “more is better.”

As in, “we’ll plant a trillion trees, or we’ll plant more than a trillion trees, and we are going to get more cooling, right?” Fahrenbach said. “That’s something we show is just not the case.”

Fahrenbach researches reforestation potentials, or global maps that identify areas where trees could be planted to mitigate climate change. In this work, she and her colleagues compared three prominent reforestation potentials to determine the effect of tree placement on local and global temperatures.

One scenario involved reforesting about 926 million hectares focused mostly on the tropics and resulted in about 0.25°C of cooling by 2100. Another called for reforesting 894 million hectares, including large areas in northern temperate and polar latitudes, and resulted in 0.13°C of cooling by 2100.

The third scenario involved planting forests strategically over only 440 million hectares of mostly tropical and subtropical land (less than half of the area covered in the other scenarios) but also resulted in 0.13°C of cooling. Geography, the findings suggest, may matter more than quantity when it comes to the cooling benefits of reforestation efforts.

Let’s Get (Biogeo)physical

The researchers modeled all three scenarios using the same parameters: Trees were planted from 2015 to 2070 and then remained steady in their population until 2100.

Planting trees in one area doesn’t just change the local temperature but has effects across the world.

All three models identified reforestation opportunities in regions such as the eastern United States, Amazonia, the Congo rainforest, and eastern China, as well as regions for which reforestation would not be as impactful, such as polar regions in the Northern Hemisphere. The researchers also found significant temperature changes across the Atlantic and Indian oceans as a result of atmospheric changes induced by reforestation, demonstrating an interconnected reality: Planting trees in one area doesn’t just change the local temperature but has effects across the world.

These local and nonlocal effects can be explained by a combination of biogeochemical and biogeophysical effects.

A biogeochemical effect relates to the movement of chemicals or chemical elements, such as trees absorbing carbon from the atmosphere.

A biogeophysical effect relates to the physical results of changing the land’s surface: Placing a tree in a snowy region, for instance, decreases the land’s albedo, meaning it causes the land surface to become darker and absorb more light, leading to more local heat. This rise in surface temperature also raises air temperature, creating cascading effects on wind patterns and oceanic currents.

Considering both processes together is essential for understanding whether a net cooling or net heating effect exists, but most policies focus only on biogeochemical effects, seeing trees solely for their ability to absorb carbon from the atmosphere, Fahrenbach said. They include prominent international policies such as the Paris Agreement and the United Nations’ Framework for REDD+.

“Really, we would also need to consider the biogeophysical effects,” Fahrenbach said. “That’s harder to do, right, considering those nonlocal effects, because just imagine, some country is going to plant a lot of trees, and that’s going to lead to warming somewhere else.”

A Call to Policymakers

Emilio Vilanova, a forest ecologist at the climate action nonprofit Verra, wrote by email, “The most important message for me is that this study emphasizes something that is often not well addressed in reforestation projects: Reforestation is not just about planting trees—it’s about designing where new forests go to maximize benefits and avoid unintended consequences.”

“Reforestation is a helpful tool, not a stand-alone solution to climate change.”

Vilanova also said the study puts the potential for reforestation efforts to address climate change in perspective. “Even very large reforestation efforts would only reduce global temperatures by about 0.13–0.25°C by the end of the century,” he said. “While meaningful, this finding also reinforces that reforestation is a helpful tool, not a stand-alone solution to climate change.”

Though the limited potential for change is sobering, the authors and Vilanova pointed out that this change does matter and that it matters how we think of our approach. They advocate for policies that adopt reforestation strategies based on location and that acknowledge both the local and nonlocal effects of reforestation.

“We really need to make sure that where we plant first, it has benefits locally, it has benefits globally,” Fahrenbach said.

—Andrew Meissen (@AndrewMeissen), Science Writer

22 April 2026: This article was updated to correct Nora Fahrenbach’s position at ETH Zurich.

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Citation: Meissen, A. (2026), Location, location, location: The “where” of reforestation may matter more than the extent, Eos, 107, https://doi.org/10.1029/2026EO260125. Published on 22 April 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

The evolution of rivers that split into multiple channels is a scientific challenge in terms of modeling and prediction. On the other hand, these rivers are widespread and play a key role for ecosystems’ life, groundwater recharge, and therefore, water security. They are also extremely sensitive to hydroclimatic changes, leading to shifts in precipitation, erosion and sediment transport.

Zhao et al. [2026] investigate the drivers of river evolution for 97 multithread river reaches worldwide, spanning diverse climates and morphologies. The study reveals the key role of intermittency for river evolution. In particular, higher flow intermittency could lead to more even flow partitioning among threads, therefore impacting hydrology and ecosystems. With flow variability increasing after climate change, rivers are likely to increase their thread count, thus impacting livelihoods and ecosystems.

Two example multithread reaches shown in Landsat images from (b) the Irtysh River (wandering) and (c) the Yukon River (braided). Credit: Zhao et al. [2026], Figure 1(b,c)

Citation: Zhao, F., Ganti, V., Chadwick, A., Greenberg, E., McLeod, J., Liu, Y., et al. (2026). Global hydroclimatic controls on multithread River dynamics. AGU Advances, 7, e2025AV002166. https://doi.org/10.1029/2025AV002166

—Alberto Montanari, Editor-in-Chief, AGU Advances

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.

New climate stripes for cities and countries all over the world have been launched to mark Earth Day (April 22). The updated graphics, which now include an additional stripe to represent temperatures from 2025, show the rapid impact that global warming is having on individual nations and regions.

SummaryDistributed Acoustic Sensing (DAS) captures seismic wavefields through precise measurement of phase changes in back-scattered laser pulse signals in an optical fiber that reflect distributed strains or strain rates over continuous fiber segments. The limitation of the DAS wavefield measurement for near surface imaging remains unclear and is worthy of verification with conventional dense nodal arrays. This study compares co-located DAS and dense nodal array recordings in near-surface active surveys conducted in Shenzhen, China. Our field experiment reveals the spatially fixed, step-like distortions of coherent signals in DAS wavefield recordings. These artifacts are attributed to the gauge-length spatial average acting upon fiber segments with heterogeneous sensitivity, which can arise from variations in backscatter intensity and cable coupling conditions. These distortions cause partial deviations between waveforms of DAS and co-located seismometer from their theoretical relationship. A statistical comparison of phase differences between DAS and seismometer waveforms across all nodal points reveals a normal distribution, indicating the prevalence of such distortions in DAS recordings. Moreover, the distortion becomes more severe as frequency increases, resulting in overly dispersed phase difference distributions between DAS and seismometers. This leads to discrepancies in the dispersion curves extracted from them at high frequencies, as dispersion extraction depends on the relative energy peaks contributed by the dominant channels. This study demonstrates that within the frequency range not severely affected by distortion, DAS can effectively extract comparable dispersion curves and velocity structure profiles in place of the nodal array for near-surface imaging applications, as validated through full-profile comparisons. But the DAS wavefield distortions limit advanced applications of the complete wavefield for better subsurface characterization, and imply that DAS data simulation and instrument response analysis should consider channel ensembles.

Soil biologist Eric Slessarev has some advice for conservationists, landscapers, and farmers with fallow fields: Go touch deep-rooted grass. Or better yet, go plant some. Slessarev, an assistant professor of ecology and evolutionary biology in Yale's Faculty of Arts and Sciences, is the first author of a new study in Earth's Future showing that deep-rooted grasses store significantly more carbon in their root biomass than shallow-rooted crops—without harming the existing organic material already in the ground.

For decades, scientists have worked to improve predictions of El Niño-Southern Oscillation (ENSO), a climate powerhouse that can cause droughts, flooding, marine heat waves, and more around the world. Researchers from the University of Hawai'i at Mānoa have published a study in Geophysical Research Letters showing that they can skillfully predict El Niño and La Niña 15 months ahead of time using only observations of the ocean surface temperature and height—no complex climate model needed.

Since 1989, Utah’s Great Salt Lake has lost some 70% of its surface area, reducing its ecosystem services and creating stretches of drying lake bed (playa) that send toxic dust into the air.

That drying ground has also provided opportunities for scientists to survey what lies below the lake’s floor. In a study published in Geosciences, researchers revealed glimpses of fresh water and salt water, with some fresh water lurking only a few meters below the surface. The work could provide clues for conserving the lake, a crucial resource for both the ecology and the economy of the region.

Salt Lake, Fresh Water

In 2023, Michael Thorne and colleagues began using a technique known as electrical resistivity tomography (ERT), which can reveal the presence of fresh or salty water, at dozens of spots near the southern and eastern edges of the Great Salt Lake. Thorne is a geophysicist at the University of Utah in Salt Lake City and a coauthor of the new study.

The lake’s desiccation allowed the researchers to access areas where “at previous times, you would never be able to do measurements because [they] would be underwater,” said Thorne.

Establishing a network of ERT sensors requires robust fieldwork. Over the course of long days in the field, Mason Jacketta, lead author of the new study, and others placed electrodes into the ground a few meters apart, making lines that stretched hundreds of meters. Between pairs of electrodes, they measured the resistance to electrical current. Salty water, filled with electricity-conducting ions, has lower resistance than fresh water.

Paired with information on the rock and sediment beneath the surface, as well as with measurements from nearby wells, the ERT data allowed the team to work out a profile of how electrical resistance varied with depth and to figure out what kind of water seeped through pores in the ground below. The team shared the results of their work on the southern part of the lake in Geosciences, while more in-depth findings about the eastern shore will appear in an upcoming publication.

“What this is really showing is that [fresh water is] prevalent all over the place.”

At many of the sites, Jacketta and others found fresh water near the surface.

“What this is really showing is that [fresh water is] prevalent all over the place,” said Elliot Jagniecki, a geologist at the Utah Geological Survey who wasn’t part of the work.

That fresh water was often in close proximity to patches of salty groundwater. At one spot in the southeastern part of the lake, the team found a shallow layer of brine. But right below that, at only 5 meters of depth, they encountered fresh water. At the team’s most northern study site, they found fresh water around 2 meters deep. On the southern shore, they found fresh water in some places as shallow as 2.8 meters.

Mysterious Formations

The team’s results also helped explain curious features around the Great Salt Lake, including mounds made of salt and islands made of reeds.

The lacy-looking layers of the lake’s so-called mirabilite mounds form in the winter, when the cold freezes upwelling salty water, concentrating its salts. With measurements taken next to where some mirabilite mounds form, the researchers could visualize the underground conduits that send salty water to the surface.

While mirabilite mounds form close to shore, mounds made of Phragmites reeds appear in the lake’s interior as well as along its periphery. Thorne and his colleague William Johnson first noticed these mysterious circles popping up in Google Maps more than a decade ago. When they went to investigate, they found Phragmites.

“The population of Phragmites around the Great Salt Lake is really not allowing fresh groundwater to go back into the Great Salt Lake.”

In the new work, the team placed a line for electrical resistivity tomography straight through a Phragmites mound. These reeds wouldn’t be able to survive in the lake’s briny water, Thorne said, but the team’s results showed fresh water rising right to where the invasive reeds grew thick.

“The population of Phragmites around the Great Salt Lake is really not allowing fresh groundwater to go back into the Great Salt Lake,” said study coauthor Tonie van Dam, a geophysicist at the University of Utah. The reeds suck up some 70,000 acre-feet of fresh water that could go back into the lake, she said. In “sucking up [fresh water] for their own existence,” van Dam explained, the reeds crowd out native plant species that provide habitat for native birds.

More Than a Beautiful Landscape

Overall, the study provides a new picture of the fresh and salty groundwater beneath the lake and how these resources feed what people observe at the surface.

It’s also helped to prompt other work, Thorne said, including one recent study in which researchers used a helicopter carrying a wire loop to create and sense electrical currents underground. That study, published in Scientific Reports, suggested there could be a large amount of fresh water under one part of the lake.

But that work is a proof of concept, Jagniecki said, and accessing such potential aquifers might not be sufficient to help address the lake’s current desiccation. Even if they could, refilling them could take thousands of years. “I just don’t think that’s a solution,” he said.

Saline lakes are fragile ecosystems sensitive to climate change, Jagniecki said. The Great Salt Lake harbors plenty of life, such as brine shrimp that become food for a host of migratory birds that use the lake as a stopover. Mineral extraction and the use of brine shrimp for feed in aquaculture are important drivers of Utah’s economy.

Getting a better understanding of how saline lake systems function could be helpful in conserving them and maintaining the resources they provide humans, Jagniecki explained.

“It’s actually more than that. It’s a beautiful landscape,” he said.

—Carolyn Wilke, Science Writer

Citation: Wilke, C. (2026), What’s below the Great Salt Lake? More water, Eos, 107, https://doi.org/10.1029/2026EO260127. Published on 21 April 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

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

如果人类想要在太空生活，无论是在航天器里还是在火星上，首先要解决的一个问题就是如何获取水，来满足饮用、卫生需求以及为维持生命所需的植物提供水分。即便只是将水运送到近地轨道上的国际空间站（ISS），也需要花费数万美元。因此，找到在太空中高效、持久且可靠地获取和再利用水资源的方法，对于长期在太空居住至关重要。

目前的系统，比如国际空间站上的环境控制与生命支持系统（ECLSS），为闭合式水回收提供了蓝图，但它们还需要改进才能适应未来的应用。与此同时，近期的技术和科学进步正为在严苛环境下寻找、净化和管理水资源开辟新的途径。在一篇新的综述中，Olawade等人概述了地外水资源管理的现状，以及该领域的前景和挑战。

作者指出，太空水系统需要具备闭环、高效和持久耐用的特性，同时还要满足低能耗的要求。目前，ECLSS能耗过高，其效率可能也不足以满足长期任务的需求。未来建议采用的过滤和回收方法包括：利用光催化技术通过光线净化水，利用生物反应器过滤尿液和废水，利用离子交换系统去除提取水中的溶解盐和重金属，以及利用紫外线或臭氧消毒杀灭病原体。每种方法各有优缺点：例如，生物反应器中的微生物燃料电池可以发电，而光催化净化则能耗较低。

在月球或火星这样的地方获取水，要么需要从风化层中提取水，要么需要钻探冰体。如何为水回收系统提供足够的能源也是一个问题，因此开发节能系统是需要优先考虑的事项。水系统的耐久性也很重要，既要保护宇航员的安全，又要能减少繁重的维护工作。

新兴技术有望应对其中许多挑战。作者们指出两个具有巨大应用前景的领域，一是纳米技术的发展，它可用于制造定制化程度更高、过滤效果更佳且耐污染的膜材料，二是人工智能（AI）技术在水系统自主管理中的应用。(Water Resources Research, https://doi.org/10.1029/2025WR041273, 2026)

—科学撰稿人Nathaniel Scharping (@nathanielscharp)

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

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

Text © 2026. AGU. CC BY-NC-ND 3.0
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Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Atmospheres

The 2018 Camp Fire was the deadliest and most destructive wildfire in California history. The Camp Fire spread extremely rapidly, driven by strong winds and dry fuels, but also by organized long-range spotting, i.e. lofting and downwind fallout of burning embers to ignite new fires.

Using operational Doppler radar and satellite observations, Lareau [2026] provides the first high resolution depiction of spotting behavior during an extreme wildfire. Observations show that spot fire events for the Camp Fire occurred 5-10 kilometers ahead of the fire front, quickly merging into new fire lines. Spot fires are not random but aligned within coherent fallout zones that are shaped by plume dynamics and background winds. These results show that operational weather radar can identify lofting and fallout regions in real time, providing a new way to anticipate spotting-driven fire spread and improve early warnings for fast-moving wildfires.

(a) Along wind cross section of Camp Fire plume reflectivity observed by radar measurements, showing distinct updrafts (white arrows) and ashfall regions (blue dashed arrow). Spot fires within 10 minutes of these radar measurements are shown as filled cyan triangles. (b) Map of column maximum radar reflectivity and fire perimeter. In both panels the black dashed line indicates the eastern edge of the town of Paradise, California. Credit: Lareau [2026], Figure 6ab

Citation: Lareau, N. P. (2026). Plume-coupled long-range spotting drove the explosive spread of the 2018 Camp Fire. Journal of Geophysical Research: Atmospheres, 131, e2025JD045798. https://doi.org/10.1029/2025JD045798

—William Randel, Editor, JGR: Atmospheres

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): E. A. Bogdanov, A. A. Kudryavtsev, and Chengxun Yuan

This study formulates a two-dimensional self-consistent kinetic model for numerical simulations a hollow-cathode glow discharge. This model includes a solution of the spatially inhomogeneous Boltzmann kinetic equation for electrons, taking into account both energy and two spatial variables: the long…

[Phys. Rev. E 113, 045214] Published Tue Apr 21, 2026

Author(s): G. G. Plunk, A. G. Goodman, P. Xanthopoulos, P. Costello, H. M. Smith, K. Aleynikova, C. D. Beidler, M. Drevlak, S. Stroteich, and P. Helander

Recent stellarator reactor designs demonstrate mostly outward turbulent particle transport, which, without advanced fueling technology, inhibits the formation of density gradients needed for confinement. We introduce “SQuID-τ,” a self-fueling quasi-isodynamic stellarator capable of sustaining densit…

[Phys. Rev. E 113, 045215] Published Tue Apr 21, 2026

Author(s): A. Bañón Navarro, A. Di Siena, F. Jenko, A. Merlo, and E. Laude

Despite substantial advances in mitigating turbulent heat losses, including those achieved in the stable quasi-isodynamic design family [J. Plasma Phys. 89, 905890504 (2023); PRX Energy 3, 023010 (2024)], particle confinement remains a principal performance bottleneck in modern quasi-isodynamic stel…

[Phys. Rev. E 113, L043204] Published Tue Apr 21, 2026

A research team with scientists from MARUM—Center for Marine Environmental Sciences at the University of Bremen studied the hemispheric origin of Indonesian Throughflow (ITF) and found a high Southern Hemispheric contribution over the past 800,000 years. The results, now published in the journal Nature Communications, highlight an important and direct pathway from high southern latitudes to the tropical oceans.

USC researchers are developing a computational model that combines satellite data and physics-based simulations to forecast a wildfire's path, intensity, and growth rate. If you've ever been evacuated from your home during a wildfire, you'll be aware of the terrifying unpredictability of the situation. From your location on the ground—rapidly gathering a few vital belongings and attempting to identify the best route to safety—there's no way of knowing how fast a fire is growing or which direction it's likely to take.

The biological carbon pump moves carbon from near the ocean's surface to deeper regions, maintaining the upper ocean's ability to absorb carbon from the atmosphere. One component of this system is driven by eddies, or relatively small-scale circular water currents powered by physical instabilities within the ocean. Previous estimates have suggested the eddy subduction pump may play a large role in moving carbon deep into the ocean, but the absence of global synthesis leaves the question open.

Publication date: April 2026

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 281

Author(s):

Publication date: April 2026

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 281

Author(s): Kavita, Saurabh Das, Nuncio Murukesh

Publication date: April 2026

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 281

Author(s): Ewen Jaffré, Christophe Bellisario, Philippe Keckhut, Pierre Simoneau, Pierre-Yves Froissart, Alain Hauchecorne

Publication date: April 2026

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Volume 281

Author(s): James M. Weygand, Adnane Osmane