A team of the world’s best ice and climate researchers studied a handful of recently publicized engineering concepts for protecting Earth’s polar ice caps and found that none of them are likely to work. Their peer-reviewed research, published Tuesday, shows some of the untested ideas, such as dispersing particles in the atmosphere to dim sunlight or trying to refreeze ice sheets with pumped water, could have unintended and dangerous consequences. The various speculative notions that have been floated, mainly via public relations efforts, include things such as spreading reflective particles over newly formed sea ice to promote its persistence and growth; building giant ocean-bottom sea walls or curtains to deflect warmer streams of water away from ice shelves; pumping water from the base of glaciers to the surface to refreeze it, and even intentionally polluting the upper atmosphere with sulfur-based or other reflective particles to dim sunlight. Research shows the particle-based sunlight-dimming concept could shift rainfall patterns like seasonal monsoons critical for agriculture in some areas, and also intensify regional heat, precipitation and drought extremes. And the authors of the new paper wrote that some of the mechanical interventions to preserve ice would likely disrupt regional ocean ecosystems, including the marine food chain, from tiny krill to giant whales. ### Newsletters We deliver climate news to your inbox like nobody else. Every day or once a week, our original stories and digest of the web’s top headlines deliver the full story, for free. * ### ICN Weekly #### Saturdays Our #1 newsletter delivers the week’s climate and energy news – our original stories and top headlines from around the web. Get ICN Weekly * ### Inside Clean Energy #### Thursdays Dan Gearino’s habit-forming weekly take on how to understand the energy transformation reshaping our world. 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Lead author Martin Siegert, a glaciologist at the University of Exeter, said that to provide a comprehensive view of the challenges, the new paper included 40 authors with expertise in fields including oceanography, marine biology, glaciology and atmospheric science. The paper counters a promotional geo-engineering narrative with science-based evidence showing the difficulties and unintended consequences of some of the aspirational ventures, he said. Most geoengineering ideas are climate Band-Aids at best. They only address symptoms, he added, but don’t tackle the root cause of the problem—greenhouse gas emissions. “I think it’s fair to say that the promotion of some of these ideas have not provided a sense of just how difficult it would be,” Siegert said. “So what you get is the maximizing of the potential of doing it and minimizing the challenge of it ever happening. It becomes a sort of distorted, one-sided proposition.” To assess the feasibility of five specific concepts, he said they developed a set of questions that could also apply to geoengineering proposals in areas other than the poles. In nearly every case, they found that the costs and logistics are prohibitive, and that there’s no reason to think they would be effective in protecting ice or reducing the impacts of global warming in other ways. The first question, he said, is whether the idea would even work in practice. Then, it’s important to think about risks, both the obvious ones and the unexpected side effects that might come with any intervention large enough to affect the climate. Money is an obvious factor, since these kinds of projects could cost tens or even hundreds of billions of dollars. Size and timing matter, he continued. Any plan must be able to grow to a scale that truly helps within the next few decades to help reach global climate goals. “We have to avoid giving people false hope by suggesting that climate change can be fixed without cutting carbon emissions, which is the only real solution,” he said, adding that special care is also needed in the polar regions because of their harsh conditions, logistical hurdles and delicate ecosystems. In places such as Antarctica, he added, international treaties meant to protect the environment would make large-scale interventions very difficult, if not impossible. “It’s not that we wanted to do this study, but there is a very small minority that is really pushing this,” said co-author James Kirkham, chief science advisor for a group of more than 20 countries that first joined together at the 2022 COP27 U.N. climate talks in Egypt to focus more attention on the threat of melting ice and rising sea levels. The following year at COP28 in Dubai, he noted that numerous events promoted concepts that are generally grouped under the term “geoengineering,” which refers to artificially and intentionally intervening with parts of the climate system. Many climate scientists were alarmed that some of the geoengineering ideas, no matter how far-fetched, seemed to be gaining traction with a few policymakers. In some cases, the presentations were designed to look like they were sponsored by national pavilions, “even though at least the people we’ve talked to within these administrations don’t want anything to do with this at all,” Kirkham said. “The thing that really wound us up was that they were pitching these fringe ideas as if they had the backing of the entire research community.” The assessment shows that “no current geoengineering idea passes an objective and comprehensive test regarding its use in the coming decades,” he said. In an email, Kirkham wrote that most geoengineering ideas had long been “dismissed and ignored” by the mainstream climate science community. But in recent years, “there seems to have been a shift … with a lot more money flowing into these sorts of projects and the hiring of experienced and slick PR people to get these ideas out there into the media,” he said. ## About This Story Perhaps you noticed: This story, like all the news we publish, is free to read. That’s because Inside Climate News is a 501c3 nonprofit organization. We do not charge a subscription fee, lock our news behind a paywall, or clutter our website with ads. We make our news on climate and the environment freely available to you and anyone who wants it. That’s not all. We also share our news for free with scores of other media organizations around the country. Many of them can’t afford to do environmental journalism of their own. We’ve built bureaus from coast to coast to report local stories, collaborate with local newsrooms and co-publish articles so that this vital work is shared as widely as possible. Two of us launched ICN in 2007. Six years later we earned a Pulitzer Prize for National Reporting, and now we run the oldest and largest dedicated climate newsroom in the nation. We tell the story in all its complexity. We hold polluters accountable. We expose environmental injustice. We debunk misinformation. We scrutinize solutions and inspire action. Donations from readers like you fund every aspect of what we do. If you don’t already, will you support our ongoing work, our reporting on the biggest crisis facing our planet, and help us reach even more readers in more places? Please take a moment to make a tax-deductible donation. Every one of them makes a difference. Thank you, David Sassoon Founder and Publisher Vernon Loeb Executive Editor ### Share This Article * * * * * * Republish ### Bob Berwyn #### Reporter, Austria Bob Berwyn is an Austria-based reporter who has covered climate science and international climate policy for more than a decade. Previously, he reported on the environment, endangered species and public lands for several Colorado newspapers, and also worked as editor and assistant editor at community newspapers in the Colorado Rockies. * @bberwyn * [email protected]

“carriages on many routes pushing 50 years old” Sounds accurate. I took my first sleeper train from Dresden to Amsterdam last week, and it was the worst train experience of my life. Carriage looked like it was from the 60’s. https://www.theguardian.com/commentisfree/2025/jun/11/europe-was-promised-a-new-golden-age-of-the-night-train-why-are-we-still-waiting #trains #eu… (1/4)

A critical measure of the ocean’s health suggests that the world’s marine systems are in greater peril than scientists had previously realized and that parts of the ocean have already reached dangerous tipping points. A study, published Monday in the journal Global Change Biology _,_ found that ocean acidification—the process in which the world’s oceans absorb excess carbon dioxide from the atmosphere, becoming more acidic—crossed a “planetary boundary” five years ago. “A lot of people think it’s not so bad,” said Nina Bednaršek, one of the study’s authors and a senior researcher at Oregon State University. “But what we’re showing is that all of the changes that were projected, and even more so, are already happening—in all corners of the world, from the most pristine to the little corner you care about. We have not changed just one bay, we have changed the whole ocean on a global level.” The new study, also authored by researchers at the U.K.’s Plymouth Marine Laboratory and the National Oceanic and Atmospheric Administration (NOAA), finds that by 2020 the world’s oceans were already very close to the “danger zone” for ocean acidity, and in some regions had already crossed into it. ### Newsletters We deliver climate news to your inbox like nobody else. Every day or once a week, our original stories and digest of the web’s top headlines deliver the full story, for free. * ### ICN Weekly #### Saturdays Our #1 newsletter delivers the week’s climate and energy news – our original stories and top headlines from around the web. Get ICN Weekly * ### Inside Clean Energy #### Thursdays Dan Gearino’s habit-forming weekly take on how to understand the energy transformation reshaping our world. 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Scientists had determined that ocean acidification enters this danger zone or crosses this planetary boundary when the amount of calcium carbonate—which allows marine organisms to develop shells—is less than 20 percent compared to pre-industrial levels.**** The new report puts the figure at about 17 percent. “Ocean acidification isn’t just an environmental crisis, it’s a ticking time bomb for marine ecosystems and coastal economies,” said Steve Widdicombe, director of science at the Plymouth lab, in a press release. “As our seas increase in acidity, we’re witnessing the loss of critical habitats that countless marine species depend on and this, in turn, has major societal and economic implications.” Scientists have determined that there are nine planetary boundaries that, once breached, risk humans’ abilities to live and thrive. One of these is climate change itself, which scientists have said is already beyond humanity’s “safe operating space” because of the continued emissions of heat-trapping gases. Another is ocean acidification, also caused by burning fossil fuels. In 2023, researchers determined that six of these boundaries had already been crossed. The new research adds a worrying seventh. The study, which was based on measurements from ice cores and data models, found that the acidity of the ocean was worse in deeper waters. At about 200 meters below the ocean’s surface, 60 percent of the ocean’s waters had already crossed the 20-percent threshold, compared to about 40 percent at the ocean’s surface. “Most ocean life doesn’t just live at the surface—the waters below are home to many more different types of plants and animals,” said Helen Findlay, a biological oceanographer with the Plymouth lab and lead author of the new study “Since these deeper waters are changing so much, the impacts of ocean acidification could be far worse than we thought.” The ocean’s increasing acidity has already led to tropical and subtropical reefs losing more than 40 percent of their habitats. In polar regions, sea butterflies—a crucial component of marine food webs—have lost more than 60 percent. Coastal shellfish species have lost 13 percent of the habitats in which they can function. “The previous documentation on ocean and planetary boundaries for ocean acidification had suggested we were close to but did not exceed the boundary yet,” said Richard Feely, a NOAA oceanographer and co-author of the study. “What this report says is that when you consider the subsurface waters—and in particular when you consider the environments where there is tremendous sensitivity to ocean acidification—the high latitude polar regions and the upwelling regions on the West Coast—those regions have seen tremendous impact.” Feely noted that these regions tend to be the ocean’s most productive. The study comes as the top ocean policy and marine researchers gather in France for the United Nations Ocean Conference to address the worsening crisis facing the world’s oceans, from plastic pollution to deep-sea mining. “We live in times where studies like this are not making an immediate impact on policy anymore, which is unfortunate,” Bednaršek said. “But I think it’s extremely important to document these changes, and hopefully this will have an impact on policy and politics.” ## About This Story Perhaps you noticed: This story, like all the news we publish, is free to read. That’s because Inside Climate News is a 501c3 nonprofit organization. We do not charge a subscription fee, lock our news behind a paywall, or clutter our website with ads. We make our news on climate and the environment freely available to you and anyone who wants it. That’s not all. We also share our news for free with scores of other media organizations around the country. Many of them can’t afford to do environmental journalism of their own. We’ve built bureaus from coast to coast to report local stories, collaborate with local newsrooms and co-publish articles so that this vital work is shared as widely as possible. Two of us launched ICN in 2007. Six years later we earned a Pulitzer Prize for National Reporting, and now we run the oldest and largest dedicated climate newsroom in the nation. We tell the story in all its complexity. We hold polluters accountable. We expose environmental injustice. We debunk misinformation. We scrutinize solutions and inspire action. Donations from readers like you fund every aspect of what we do. If you don’t already, will you support our ongoing work, our reporting on the biggest crisis facing our planet, and help us reach even more readers in more places? Please take a moment to make a tax-deductible donation. Every one of them makes a difference. Thank you, David Sassoon Founder and Publisher Vernon Loeb Executive Editor ### Share this article * * * * * * Republish ### Georgina Gustin #### Reporter, Washington, D.C. Georgina Gustin covers agriculture for Inside Climate News, and has reported on the intersections of farming, food systems and the environment for much of her journalism career. Her work has won numerous awards, including the John B. Oakes Award for Distinguished Environmental Journalism, and she was twice named the Glenn Cunningham Agricultural Journalist of the Year, once with ICN colleagues. She has worked as a reporter for The Day in New London, Conn., the St. Louis Post-Dispatch and CQ Roll Call, and her stories have appeared in The New York Times, Washington Post and National Geographic’s The Plate, among others. She is a graduate of the Columbia University Graduate School of Journalism and the University of Colorado at Boulder. * @georginagustin.bsky.social * @georgina_gustin * [email protected]