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Paradise, California, is snatching up high-risk properties to create a defensive perimeter and prevent the town from burning again.

The 2018 Camp Fire was the deadliest wildfire in California’s history, wiping out 90% of the structures in the mountain town of Paradise and killing at least 85 people in a matter of hours. Investigations afterward found that Paradise’s town planners had ignored warnings of the fire risk to its residents and forgone common-sense preparations that would have saved lives. In the years since, the Camp Fire has consequently become a cautionary tale for similar communities in high-risk wildfire areas — places like Chinese Camp, a small historic landmark in the Sierra Nevada foothills that dramatically burned to the ground last week as part of the nearly 14,000-acre TCU September Lightning Complex.
More recently, Paradise has also become a model for how a town can rebuild wisely after a wildfire. At least some of that is due to the work of Dan Efseaff, the director of the Paradise Recreation and Park District, who has launched a program to identify and acquire some of the highest-risk, hardest-to-access properties in the Camp Fire burn scar. Though he has a limited total operating budget of around $5.5 million and relies heavily on the charity of local property owners (he’s currently in the process of applying for a $15 million grant with a $5 million match for the program) Efseaff has nevertheless managed to build the beginning of a defensible buffer of managed parkland around Paradise that could potentially buy the town time in the case of a future wildfire.
In order to better understand how communities can build back smarter after — or, ideally, before — a catastrophic fire, I spoke with Efseaff about his work in Paradise and how other communities might be able to replicate it. Our conversation has been lightly edited and condensed for clarity.
Do you live in Paradise? Were you there during the Camp Fire?
I actually live in Chico. We’ve lived here since the mid-‘90s, but I have a long connection to Paradise; I’ve worked for the district since 2017. I’m also a sea kayak instructor and during the Camp Fire, I was in South Carolina for a training. I was away from the phone until I got back at the end of the day and saw it blowing up with everything.
I have triplet daughters who were attending Butte College at the time, and they needed to be evacuated. There was a lot of uncertainty that day. But it gave me some perspective, because I couldn’t get back for two days. It gave me a chance to think, “Okay, what’s our response going to be?” Looking two days out, it was like: That would have been payroll, let’s get people together, and then let’s figure out what we’re going to do two weeks and two months from now.
It also got my mind thinking about what we would have done going backwards. If you’d had two weeks to prepare, you would have gotten your go-bag together, you’d have come up with your evacuation route — that type of thing. But when you run the movie backwards on what you would have done differently if you had two years or two decades, it would include prepping the landscape, making some safer community defensible space. That’s what got me started.
Was it your idea to buy up the high-risk properties in the burn scar?
I would say I adapted it. Everyone wants to say it was their idea, but I’ll tell you where it came from: Pre-fire, the thinking was that it would make sense for the town to have a perimeter trail from a recreation standpoint. But I was also trying to pitch it as a good idea from a fuel standpoint, so that if there was a wildfire, you could respond to it. Certainly, the idea took on a whole other dimension after the Camp Fire.
I’m a restoration ecologist, so I’ve done a lot of river floodplain work. There are a lot of analogies there. The trend has been to give nature a little bit more room: You’re not going to stop a flood, but you can minimize damage to human infrastructure. Putting levees too close to the river makes them more prone to failing and puts people at risk — but if you can set the levee back a little bit, it gives the flood waters room to go through. That’s why I thought we need a little bit of a buffer in Paradise and some protection around the community. We need a transition between an area that is going to burn, and that we can let burn, but not in a way that is catastrophic.
How hard has it been to find willing sellers? Do most people in the area want to rebuild — or need to because of their mortgages?
Ironically, the biggest challenge for us is finding adequate funding. A lot of the property we have so far has been donated to us. It’s probably upwards of — oh, let’s see, at least half a dozen properties have been donated, probably close to 200 acres at this point.
We are applying for some federal grants right now, and we’ll see how that goes. What’s evolved quite a bit on this in recent years, though, is that — because we’ve done some modeling — instead of thinking of the buffer as areas that are managed uniformly around the community, we’re much more strategic. These fire events are wind-driven, and there are only a couple of directions where the wind blows sufficiently long enough and powerful enough for the other conditions to fall into play. That’s not to say other events couldn’t happen, but we’re going after the most likely events that would cause catastrophic fires, and that would be from the Diablo winds, or north winds, that come through our area. That was what happened in the Camp Fire scenario, and another one our models caught what sure looked a lot like the [2024] Park Fire.
One thing that I want to make clear is that some people think, “Oh, this is a fire break. It’s devoid of vegetation.” No, what we’re talking about is a well-managed habitat. These are shaded fuel breaks. You maintain the big trees, you get rid of the ladder fuels, and you get rid of the dead wood that’s on the ground. We have good examples with our partners, like the Butte Fire Safe Council, on how this works, and it looks like it helped protect the community of Cohasset during the Park Fire. They did some work on some strips there, and the fire essentially dropped to the ground before it came to Paradise Lake. You didn’t have an aerial tanker dropping retardant, you didn’t have a $2-million-per-day fire crew out there doing work. It was modest work done early and in the right place that actually changed the behavior of the fire.
Tell me a little more about the modeling you’ve been doing.
We looked at fire pathways with a group called XyloPlan out of the Bay Area. The concept is that you simulate a series of ignitions with certain wind conditions, terrain, and vegetation. The model looked very much like a Camp Fire scenario; it followed the same pathway, going towards the community in a little gulch that channeled high winds. You need to interrupt that pathway — and that doesn’t necessarily mean creating an area devoid of vegetation, but if you have these areas where the fire behavior changes and drops down to the ground, then it slows the travel. I found this hard to believe, but in the modeling results, in a scenario like the Camp Fire, it could buy you up to eight hours. With modern California firefighting, you could empty out the community in a systematic way in that time. You could have a vigorous fire response. You could have aircraft potentially ready. It’s a game-changing situation, rather than the 30 minutes Paradise had when the Camp Fire started.
How does this work when you’re dealing with private property owners, though? How do you convince them to move or donate their land?
We’re a Park and Recreation District so we don’t have regulatory authority. We are just trying to run with a good idea with the properties that we have so far — those from willing donors mostly, but there have been a couple of sales. If we’re unable to get federal funding or state support, though, I ultimately think this idea will still have to be here — whether it’s five, 10, 15, or 50 years from now. We have to manage this area in a comprehensive way.
Private property rights are very important, and we don’t want to impinge on that. And yet, what a person does on their property has a huge impact on the 30,000 people who may be downwind of them. It’s an unusual situation: In a hurricane, if you have a hurricane-rated roof and your neighbor doesn’t, and theirs blows off, you feel sorry for your neighbor but it’s probably not going to harm your property much. In a wildfire, what your neighbor has done with the wood, or how they treat vegetation, has a significant impact on your home and whether your family is going to survive. It’s a fundamentally different kind of event than some of the other disasters we look at.
Do you have any advice for community leaders who might want to consider creating buffer zones or something similar to what you’re doing in Paradise?
Start today. You have to think about these things with some urgency, but they’re not something people think about until it happens. Paradise, for many decades, did not have a single escaped wildfire make it into the community. Then, overnight, the community is essentially wiped out. But in so many places, these events are foreseeable; we’re just not wired to think about them or prepare for them.
Buffers around communities make a lot of sense, even from a road network standpoint. Even from a trash pickup standpoint. You don’t think about this, but if your community is really strung out, making it a little more thoughtfully laid out also makes it more economically viable to provide services to people. Some things we look for now are long roads that don’t have any connections — that were one-way in and no way out. I don’t think [the traffic jams and deaths in] Paradise would have happened with what we know now, but I kind of think [authorities] did know better beforehand. It just wasn’t economically viable at the time; they didn’t think it was a big deal, but they built the roads anyway. We can be doing a lot of things smarter.
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Current conditions: Tropical Storm Melissa is gathering enough strength to potentially reach Category 5 status as the cyclone tracks northward toward Florida and the Bahamas • Up to six storms are barreling toward the Pacific Northwest, threatening flooding from up to six inches of rain on Saturday • Parts of South Africa’s coast are roasting in temperatures above 109 degrees Fahrenheit.

The Department of the Interior unveiled a package of executive actions opening the Arctic National Wildlife Refuge to oil drilling and mining exploration, a controversial move that fulfills a decades-long ambition for industry. The decision marks what The New York Times described as “the latest twist in a long-running fight over the fate of the refuge’s coastal plain, an unspoiled expanse of 1.56 million acres that is believed to sit atop billions of barrels of oil but is also a critical habitat for polar bears, caribou, migratory birds, and other wildlife.” During his first term, in 2017, President Donald Trump signed a tax bill that required two oil and gas leases in the area, but the Biden administration later blocked those leases. “From day one, President Trump directed us to unlock Alaska’s energy and resource potential while honoring commitments to the state and local communities,” Secretary of the Interior Doug Burgum said in a statement. “By reopening the Coastal Plain and advancing key infrastructure, we are strengthening energy independence, creating jobs and supporting Alaska’s communities while driving economic growth across the state.”
The Trump administration has made industrializing the northernmost frontier state a key priority, approving a mining road though pristine forested lands and taking an equity stake for the federal government in the company aiming to extract minerals in the region. But the Environmental Protection Agency also yanked funding meant to help reinforce infrastructure in Alaska Native villages against warming-fueled floods, dismissing the money as left-wing ideologically driven “diversity, equity, and inclusion” spending, as I wrote in this newsletter. Those very communities were devastated by a typhoon earlier this month, displacing residents, with evacuees struggling to adjust to life in Alaska’s “concrete jungles,” the Northern Journal reported.
Heatmap’s Robinson Meyer has a big scoop this morning: Geoengineering startup Stardust Solutions is set to announce that it has raised $60 million in venture capital to develop the tools needed to artificially cool the planet by reflecting sunlight away from Earth. The company, led by a team of Israeli physicists, aims to spray aerosols into the atmosphere that will bounce energy from the sun back into space to balance out the effects of greenhouse gases. The technology is on track to be ready by the end of the decade. Lowercarbon Capital led the funding round, which is the company’s second, following a $15 million seed round in 2024. Rob’s story offers a measured assessment of the dangers of potentially geoengineering the atmosphere — and the threat of failing to do so when efforts to mitigate emissions are so far from where they need to be to preserve the climate norms in which humans evolved as a species. In a line that harkens to one of my favorite books, journalist Charles C. Mann’s environmental history of the global trade network that developed after Christopher Columbus’ arrival in the Americas called 1493, Rob notes that “the Earth has not been free of human influence for millennia,” and that “the world has over and over again been remade by human hands.”
“Stardust may not play the Prometheus here and bring this particular capability into humanity’s hands,” Rob writes. “But I have never been so certain that someone will try in our lifetimes. We find ourselves, once again, in the middle of things.”
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Rivian, the maker of luxury electric trucks and SUVs, slashed more than 600 employees, representing nearly 4.5% of its roughly 15,000-person workforce, The Wall Street Journal reported Thursday. “These are not changes that were made lightly,” Rivian CEO RJ Scaringe said in an email to staff. “With the changing operating backdrop, we had to rethink how we are scaling our go-to-market functions.” The cuts were meant to help “profitably scale” the business as it prepares to launch its new R2 midsize SUV.
The move comes as electric automakers reel from the Trump administration’s elimination of the federal electric vehicle tax credit. Tesla, as I reported here yesterday, posted a nearly 40% drop in profits on Wednesday afternoon as the company lowered prices to keep costs to customers in line with what federal write-offs previously made possible. But as Andrew Moseman wrote in Heatmap, the lower prices came with stripped-down features.
The U.S. government has backed a new billion-dollar fund to invest in critical minerals along with the New York-based Orion Resource Partners and Abu Dhabi’s ADQ. The investment vehicle, dubbed the Orion Critical Mineral Consortium, was announced Thursday with support from the federal International Development Finance Corp. The funding totals more than $1.8 billion, Bloomberg reported.
This is just the Trump administration’s latest foray into mining. The Department of Defense took the largest stake earlier this year in MP Materials, the only active rare earths producer in the U.S. Since then, the administration has taken stakes in other critical minerals projects, and considered similar ownership positions in companies developing rare earths in Greenland.
VC Summer, the project to build Westinghouse’s state-of-the-art AP1000 reactor in South Carolina, became such a financial boondoggle, utility executives went to jail; The final defendant was sentenced just last year. Yet the project — widely mocked as a billion-dollar hole in the ground — may end up built after all. Utility Santee Cooper officially notified regulators this week that it plans to execute a contract to restart the project.
The announcement, part of what Heatmap’s Katie Brigham called the “nuclear dealmaking boom,” came the same day Canada’s government put up $2 billion to back a small modular reactor project in Bowmanville, Ontario. The progress north of America’s border on new reactor technologies has drawn attention from potential Democratic presidential candidates in the U.S. When New York City mayoral contender Zohran Mamdani expressed support for building new reactors in the state during this week’s debate, Arizona Senator Ruben Gallego — widely discussed as a possible White House seeker — responded to the news in a post on X: “I am all for Nuclear power in this country but it would be quicker and cheaper to buy into the Ontario plant being built and coming online by 2030.”
Mining giant Fortescue has made a breakthrough. In its latest earnings call with investors Thursday, the Australian giant said it planned to replace the trucks that carry its ore with electric alternatives. “We’re not doing this because we don’t think our total cost of ownership is going to be less,” Fortescue CEO Dino Otranto said in a statement. “Of course, we’re doing it because of that.”
A U.S. firm led by former Israeli government physicists, Stardust seeks to patent its proprietary sunlight-scattering particle — but it won’t deploy its technology until global governments authorize such a move, its CEO says.
The era of the geoengineering startup has seemingly arrived.
Stardust Solutions, a company led by a team of Israeli physicists, announced on Friday that it has raised $60 million in venture capital to develop technological building blocks that it says will make solar geoengineering possible by the beginning of next decade.
It is betting that it can be the first to develop solar geoengineering technology, a hypothetical approach that uses aerosols to reflect sunlight away from Earth’s surface to balance out the effects of greenhouse gases. Yanai Yedvab, Stardust’s CEO, says that the company’s technology will be ready to deploy by the end of the decade.
The funding announcement represents a coming out of sorts for Stardust, which has been one of the biggest open secrets in the small world of solar geoengineering researchers. The company is — depending on how you look at it — either setting out a new way to research solar radiation management, or SRM, or violating a set of informal global norms that have built up to govern climate-intervention research over time.
Chief among these: While universities, nonprofits, and government labs have traditionally led SRM studies, Stardust is a for-profit company. It is seeking a patent for aspects of its geoengineering system, including protections for the reflective particles that it hopes governments will eventually disperse in the atmosphere.
The company has sought the advice of former United Nations diplomats, federal scientists, and Silicon Valley investors in its pursuit of geoengineering technology. Lowercarbon Capital, one of the most respected climate tech venture capital firms, led the funding round. Stardust previously raised a seed round of $15 million from Canadian and Israeli investors. It has not disclosed a valuation.
Yedvab assured me that once Stardust’s geoengineering system is ready to deploy, governments will decide whether and when to do so.
But even if it is successful, Stardust’s technology will not remove climate risk entirely. “There will still be extreme weather events. We’re not preventing them altogether,” Yedvab said. Rather, tinkering with the Earth’s atmosphere on a planetary scale could help preserve something like normal life — “like the life that all of us, you, us, our children have been experiencing over the last few decades.” The new round of funding, he says, will put that dream within reach.
Yedvab, 54, has salt and pepper hair and a weary demeanor. When I met him earlier this month, he and his cofounder, Stardust Chief Product Officer Amyad Spector, had just flown into New York from Tel Aviv, before continuing on to Washington, D.C., that afternoon. Yedvab worked for many years at the center of the Israeli scientific and defense establishment. From 2011 to 2015, he was the deputy chief research scientist at the Israeli Atomic Energy Commission. He was also previously the head of the physics division at the highly classified Israeli nuclear research site in Negev, according to his LinkedIn.
Spector, 42, has also spent much of his career working for the Israeli government. He was a physics researcher at the Negev Nuclear Research Center before working on unspecified R&D projects for the government for nearly a decade, as well as on its Covid response. He left the government in December 2022.
Stardust’s story, in their telling, began in the wake of the pandemic, when they and their third cofounder — Eli Waxman, a particle physics professor at the Weizmann Institute of Science — became curious about climate change. “We started [with a] first principles approach,” Yedvab told me. What were countries’ plans to deal with warming? What did the data say? It was a heady moment in global climate politics: The United States and Europe had recently passed major climate spending laws, and clean energy companies were finally competing on cost with oil and gas companies.
Yet Yedvab was struck by how far away the world seemed to be from meeting any serious climate goal. “I think the thing that became very clear early on is that we’re definitely not winning here, right?” he told me. “These extreme weather events essentially destroy communities, drain ecosystems, and also may have major implications in terms of national security,” he said. “To continue doing what we’re doing over the next few decades and expecting materially different results will not get us where we want to be. And the implications can be quite horrific.”
Then they came across two documents that changed their thinking. The first was a 2021 report from the National Academies of Sciences in the United States, which argued that the federal government should establish “a transdisciplinary, solar geoengineering research program” — although it added that this must only be a “minor part” of the country’s overall climate studies and could not substitute for emissions reductions. Its authors seemed to treat solar geoengineering as a technology that could be developed in the near term, akin to artificial intelligence or self-driving cars.
They also found a much older article by the physicist Edward Teller — the same Teller who had battled with J. Robert Oppenheimer during the Manhattan Project. Teller had warned the oil industry about climate change as early as 1959, but in his final years he sought ways to avoid cutting fossil fuels at all. Writing in The Wall Street Journal weeks before the Kyoto Protocol meetings in 1997, an 89-year-old Teller argued that “contemporary technology offers considerably more realistic options for addressing any global warming effect” than politicians or activists were considering.
“One particularly attractive approach,” he wrote, was solar geoengineering. Blocking just 1% of sunlight could reduce temperatures while costing $100 million to $1 billion a year, he said, a fraction of the estimated societal cost of paring fossil fuels to their 1990 levels. A few years later, he wrote a longer report for the Energy Department arguing for the “active technical management” of the atmosphere rather than “administrative management” of fossil fuel consumption. He died in 2003.
The documents captivated the two scientists. What began to appeal to Yedvab and Spector was the economy of scale unlocked by the stratosphere — the way that just a few million tons of material could change the global climate. “It's very easy to understand why, if this works, the benefit could be enormous,” Yedvab said. “You can actually stop global warming. You can cool the planet and avoid a large part of the suffering. But then again, it was a very theoretical concept.” They incorporated Stardust in early 2023.
Economists had long anticipated the appeal of such an approach to climate management. Nearly two decades ago, the Columbia economist Scott Barrett observed that solar geoengineering’s economics are almost the exact opposite of climate change’s: While global warming is a “free rider” problem, where countries must collaborate to avoid burning cheap fossil fuels, solar geoengineering is a “free driver” problem, where one country could theoretically do it alone. Solar geonengineering’s risks lay in how easy it would be to do — and how hard it would be to govern.
Experts knew how you would do it, too: You would use sulfate aerosols — the tiny airborne chemicals formed when sulfur from volcanoes or fossil fuels reacts with water vapor, oxygen, and other substances in the air. In a now classic natural experiment Teller cited in his Journal op-ed, when Mount Pintabuo erupted in 1991 in the Philippines, it hurled a 20 million ton sulfur-dioxide cloud into the stratosphere, cooling the world by up to 1.3 degrees Fahrenheit before the sulfates rained out.
But to Yedvab, “sulfates look like a poor option,” he told me. Sulfates and sulfur oxides are nasty pollutants in their own right — they can cause asthma attacks, form acid rain, and may damage the ozone layer when in the stratosphere. For this reason, the International Maritime Organization adopted new rules restricting the amount of sulfur in cargo shipping fuels; these rules — in yet another natural experiment — seem to have accidentally accelerated global warming since 2020.
Yedvab and Spector anticipated another problem with sulfates: The atmosphere already contains tens of millions of tons of them. There is already so much sulfate in the sky from natural and industrial processes, they argue, that scientists would struggle to monitor whatever was released by geoengineers; Spector estimates that the smallest potential geoengineering experiment would require emitting 1 million tons of it. The chemical seemed to present an impossible trade-off to policymakers: How could a politician balance asthma attacks and acid rain against a cooler planet? “This is not something that decisionmakers can make a decision about,” Yedvab concluded.

Instead, the three founders tried starting at the end of the process, as they put it. What would an ideal geoengineering system look like? “Let’s say that we are successful in developing a system,” Yedvab said. “What will be the questions that people like you — that policymakers, the general public — will ask us?”
Any completed geoengineering system, they concluded, would need to meet a few constraints. It would need, first, a particle that could reflect a small amount of sunlight away from Earth while allowing infrared radiation from the planet’s surface to bounce back into space. That particle would need to be tested iteratively and manufactured easily in the millions of tons, which means it would also have to be low-cost.
“This needs to be a scalable or realistic particle that we know from the start how to produce at scale in the millions of tons, and at the relevant target price of a few dollars per kilo,” Yedvab said. “So not diamonds or something that we've done at the lab but have no idea how to scale it up,” Yedvab said.
It would need to be completely safe for people and the biosphere. Stardust hopes to run its particle through a safety process like the ones that the U.S. and EU subject food or other materials to, Yedvab said. “This needs to be as safe as, say, flour or some food ingredient,” Yedvab said. The particle would also need to be robust and inert in the stratosphere, and you would need some way to manage and identify it, perhaps even to track it, once it got there.
Second, the system would need some way to “loft” that particle into the stratosphere — some machine that could disperse the particle at altitude. Finally, it would need some way to make the particles observable and controllable, to make sure they are acting as intended. “For visibility, for control, for, I would say, geopolitical implications — you want to make sure you actually know where, how these particles move around, Yedvab said.
Stardust received $15 million in seed funding from the venture firm AWZ and Solar Edge, an Israeli energy company, in early 2024. Soon after, the founders got to work.
The world has come close to solving a global environmental crisis at least once before. In 1987, countries adopted the Montreal Protocol, which set out rules to eliminate and replace the chlorofluorocarbons that were destroying the stratospheric ozone hole. Nearly 40 years later, the ozone hole is showing signs of significant recovery. And more to the point, almost nobody talks about the ozone hole anymore, because someone else is dealing with it.
“I would say it was the biggest triumph of environmental diplomacy ever,” Yedvab said. “In three years, beginning to end, the U.S. government was able to secure the support of essentially all the major powers in solving a global problem.” The story is not quite that simple — the Reagan administration initially resisted addressing the ozone hole until American companies like DuPont stood to benefit by selling non-ozone-depleting chemicals — but it captures the kind of triumphant U.S.-led process that Stardust wouldn’t mind seeing repeated.
In 2024, soon after Stardust raised its seed round, Yedvab approached the Swiss-Hungarian diplomat Janos Pasztor and invited him to join the company to advise on the thicket of issues usually simplified as “governance.” These can include technical-seeming questions about how companies should test their technology and who they should seek input from, but they all, at their heart, get to the fundamentally undemocratic nature of solar geoengineering. Given that the atmosphere is a global public good, who on Earth has the right to decide what happens to it?
Pasztor is the former UN assistant secretary-general for climate change, but he was also the longtime leader of the Carnegie Climate Governance Initiative, a nonprofit effort to hammer out consensus answers to some of those questions.
Pasztor hesitated to accept the request. “It was a quadruple challenge,” he told me, speaking from his study in Switzerland. He and his wife frequently attend pro-Palestine demonstrations, he said, and he was reluctant to work with anyone from Israel as long as the country continued to occupy Gaza and the West Bank. Stardust’s status as a private, for-profit enterprise also gave him pause: Pasztor has long advocated for SRM research to be conducted by governments or academics, so that the science can happen out in the open. Stardust broke with all of that.
Despite his reservations, he concluded that the issue was too important — and the lack of any regulation or governance in the space too glaring — for him to turn the company away. “This is an issue that does require some movement,” he said. “We need some governance for the research and development of stratospheric aerosol injection … We don’t have any.”
He agreed to advise Stardust as a contractor, provided that he could publish his report on the company independently and donate his fee to charity. (He ultimately gave $27,000 to UNRWA, the UN agency for Palestinian refugees.)
That summer, Pasztor completed his recommendations, advising Stardust — which remained in stealth mode — to pursue a strategy of “maximum transparency” and publish a website with a code of conduct and some way to have two-way conversations with stakeholders. He also encouraged the company to support a de facto moratorium on geoengineering deployment, and to eventually consider making its intellectual property available to the public in much the same way that Volvo once opened its design for the three-point seatbelt.
His report gestured at Stardust’s strangeness: Here was a company that said it hoped to abide by global research norms, but was, by its very existence, flouting them. “It has generally been considered that private ownership of the means to manage the global atmosphere is not appropriate,” he wrote. “Yet the world is currently faced with a situation of de facto private finance funding [stratospheric aerosol injection] activities.”
Pasztor had initially hoped to publish his report and Stardust’s code of conduct together, he told me. But the company did not immediately establish a website, and eventually Pasztor simply released his report on LinkedIn. Stardust did not put up a website until earlier this year, during the reporting process for a longer feature about the company by the MIT-affiliated science magazine Undark. That website now features Pasztor’s report and a set of “principles,” though not the code of conduct Pasztor envisioned. They are “dragging their feet on that,” he said.
As news of the company trickled out, Stardust’s leaders grew more confident in their methods. In September 2024, Yedvab presented on Stardust’s approach to stratospheric researchers at the National Oceanic and Atmospheric Administration’s chemical sciences laboratory in Boulder, Colorado. The lab’s director, David Fahey, downplayed the importance of the talk. “There’s a stratospheric community in the world and we know all the long-term members. We’re an open shop,” he said. “We’ll talk to anyone who comes.” Stardust is the only company of its size and seriousness that has shown up, he said.
Stardust is the only company of its size and seriousness working on geoengineering, period, he added. “Stardust really stands out for the investment that they’re trying to make into how you might achieve climate intervention,” he said. “They’re realizing there’s a number of questions the world will need answered if we are going to put the scale of material in the stratosphere that they think we may need to.” (At least one other U.S. company, Make Sunsets, has claimed to release sulfates in the atmosphere and has even sold “cooling credits” to fund its work. But it has raised a fraction of Stardust’s capital, and its unsanctioned outdoor experiments set off such a backlash that Mexico banned all solar geoengineering experiments in response.)
Pasztor continued to work with Stardust throughout this year despite the company’s foot-dragging. He left this summer when he felt like he was becoming a spokesperson for a business that he merely advised. Stardust has more recently worked with Matthew Waxman, a Columbia law professor, on governance issues through the company WestExec Advisors.
Today, Stardust employs a roughly 25-person team that includes physicists, chemists, mechanical engineers, material engineers, and climate experts. Many of them are drawn from Yedvab and Spector’s previous work on Israeli R&D projects.
The company is getting closer to its goals. Yedvab told me that it has developed a proprietary particle that meets its safety and reflectivity requirements. Stardust is now seeking a patent for the material, and it will not disclose the chemical makeup until it receives intellectual property protection. The company claims to be working with a handful of academics around the world on peer-reviewed studies about the particle and broader system, although it declined to provide a list of these researchers on the record.
As Yedvab sees it, the system itself is the true innovation. Stardust has engineered every part of its approach to work in conjunction with every other part — a type of systems thinking that Yedvab and Spector presumably brought from their previous career in government R&D.
Spector described one representative problem: Tiny particles tend to attract each other and clump together when floating in the air, which would decrease the amount of time they spend in the atmosphere, he said. Stardust has built custom machinery to “deagglomerate” the particles, and it has made sure that this dispersion technology is small and light enough to sit on an aircraft flying at or near the stratosphere. (The stratosphere begins at about 26,000 feet over the poles, but 52,000 feet above the equator.)
This integrated approach is part of why Stardust believes it is much further along than any other research effort. “Whatever group that would try to do this, you would need all those types of [people] working together, because otherwise you might have the best chemist, or make the best particle, but it would not fly,” Spector said.
With the new funding, the company believes that its technology could be ready to deploy as soon as the end of this decade. By then, the company hopes to have a particle fabrication facility, a mid-size fleet of aircraft (perhaps a fraction of the size of FedEx’s), and an array of monitoring technology and software ready to deploy.
Even then, its needs would be modest. That infrastructure — and roughly 2 million tons of the unspecified particle — would be all that was required to stop the climate from warming further, Spector said. Each additional million tons a year would reduce Earth’s temperature about half of a degree.
Yet having the technology does not mean that Stardust will deploy it, Yedvab said. The company maintains that it won’t move forward until governments invite it to. “We will only participate in deployment which will be done under adequate governance led by governments,” Yedvab told me. “When you're dealing with such an issue, you should have very clear guiding principles … There are certain ground rules that — I would say in the lack of regulation and governance — we impose upon ourselves.”
He said the company has spoken to American policy makers “on both sides of the aisle” to encourage near-term regulation of the technology. “Policymakers and regulators should get into this game now, because in our view, it's only a matter of time until someone will say, Okay, I'm going and trying to do it,” Yedvab said. “And this could be very dangerous.”
There is a small and active community of academics, scientists, and experts who have been thinking and studying geoengineering for a long time. Stardust is not what almost any of them would have wished a solar geoengineering company to look like.
Researchers had assumed that the first workable SRM system would come from a government, emerging at the end of a long and deliberative public research process. Stardust, meanwhile, is a for-profit company run by Israeli ex-nuclear physicists that spent years in stealth mode, is seeking patent protections for its proprietary particle, and eventually hopes — with the help of the world’s governments — to disperse that particle through the atmosphere indefinitely.
For these reasons, even experts who in other contexts support aggressive research into deploying SRM are quite critical of Stardust.
“The people involved seem like really serious, thoughtful people,” David Keith, a professor and the founding faculty director of the Climate Systems Engineering Initiative at the University of Chicago, told me. “I think their claims about making an inert particle — and their implicit assumption that you can make a particle that is better than sulfates” are “almost certain to be wrong.”
Keith, who is on the scientific advisory board of Reflective, a San Francisco-based nonprofit that aims to accelerate SRM research and technology development, has frank doubts about Stardust’s scientific rationale. Sulfates are almost certainly a better choice than whatever Stardust has cooked up, he said, because we have already spent decades studying how sulfates act. “There’s no such particle that’s inert in the stratosphere,” he told me. “Now maybe they’ve invented something they’ll get a Nobel Prize for that violates that — but I don’t think so.”
He also rejects the premise that for-profit companies should work on SRM. Keith, to be clear, does not hate capitalism: In 2009, he founded the company Carbon Engineering, which developed carbon capture technology before the oil giant Occidental Petroleum bought it for $1.1 billion in 2023. But he has argued since 2018 that while carbon capture is properly the domain of for-profit firms, solar engineering research should never be commercialized.
“Companies always, by definition, have to sell their product,” he told me. “It’s just axiomatic that people tend to overstate the benefits and undersell the risk.” Capitalistic firms excel at driving down the cost of new technologies and producing them at scale, he said. But “for stratospheric aerosol injection, we don’t need it to be cheaper — it’s already cheap,” he continued. “We need better confidence and trust and better bounding of the unknown unknowns.”
Shuchi Talati, who founded and leads the Alliance for Just Deliberation on Solar Geoengineering, is also skeptical. She still believes that countries could find a way to do solar geoengineering for the public good, she told me, but it will almost certainly not look like Stardust. The company is in violation of virtually every norm that has driven the field so far: It is not open about its research or its particle, it is a for-profit company, and it is pursuing intellectual property protections for its technology.
“I think transparency is in every single set of SRM principles” developed since the technology was first conceived, she said. “They obviously have flouted that in their entirety.”
She doubted, too, that Stardust could actually develop a new and totally biosafe chemical, given the amount of mass that would have to be released in the stratosphere to counteract climate change. “Nothing is biosafe” when you disperse it at sufficient scale, she said. “Water in certain quantities is not biosafe.”
The context in which the company operates suggests some other concerns. Although SRM would likely make a poor weapon, at least on short time scales, it is a powerful and world-shaping technology nonetheless. In that way, it’s not so far from nuclear weapons. And while the world has found at least one way to govern that technology — the nonproliferation regime — Israel has bucked it. It is one of only four countries in the world to have never signed the Nuclear Nonproliferation Treaty. (The others are India, Pakistan, and South Sudan.) Three years ago, the UN voted 152 to 5 that Israel must give up its weapons and sign the treaty.
These concerns are not immaterial to Stardust, given Yedvab and Spector’s careers working as physicists for the government. In our interview, Yedvab stressed the company’s American connections. “We are a company registered in the U.S., working on a global problem,” he told me. “We come from Israel, we cannot hide it, and we do not want to hide it.” But the firm itself has “no ties with the Israeli government — not with respect to funding, not with respect to any other aspect of our work,” he said. “It’s the second chapter in our life,” Spector said.
Stardust may not be connected to the Israeli government, but some of its funders are. The venture capital firm AWZ, which participated in its $15 million seed round, touts its partnership with the Israeli Ministry of Defense’s directorate of defense R&D, and the fund’s strategic advisors include Tamir Pardo, the former director of the Israeli intelligence agency Mossad. “We have no connection to the Israeli government or defense establishment beyond standard regulatory or financial obligations applicable to any company operating in Israel,” a spokesperson for Stardust reiterated in a statement when I asked about the connection. “We are proud that AWZ, along with all of our investors, agrees with our mission and believes deeply in the need to address this crisis.”
One of Stardust’s stated principles is that deployment should be done under “established governance, guided by governments and authorized bodies.” But its documentation provides no detail about who those governments might be or how many governments amount to a quorum.
“The optimal case, in my view, is some kind of a multilateral coalition,” Yedvab said. “We definitely believe that the U.S. has a role there, and we expect and hope also the other governments will take part in building this governance structure.”
Speaking with Pasztor, I observed that the United States and Israel’s actions often deviate sharply from what the rest of the world might want or inscribe in law. What if they decided to conduct geoengineering themselves? “This gets into a pretty hairy geopolitical discussion, but it has to be had,” Pasztor told me. He had discussed similar issues with the company, he said, adding that “at just about every meeting he had” with the team, Stardust’s leaders hoped to “disassociate and distance themselves” from the current Israeli government. “Even when there were suggestions in my recommendations that the first step is to work through ‘your government’ — their thinking was, Okay, we will do it with the Americans,” he said.
He also discussed with the team the risks of the United States going it alone and pursuing stratospheric aerosol injection by itself. That would produce an enormous backlash, Pasztor warned, especially when the Trump administration “is doing everything contrary to what one should do” to fight climate change. “And then doing the U.S. and Israel together — given the current double geopolitical context — that would be even worse,” he said. (“Of course, they could get away with it,” he added. “Who can stop the U.S. from doing it?”)
And that hints at perhaps the greatest risk of Stardust’s existence: that it prevents progress on climate change simply because it will discourage countries from cutting their fossil fuel use. Solar geoengineering’s biggest risk has long seemed to be this moral hazard — that as soon as you can dampen the atmospheric effects of climate change, countries will stop caring about greenhouse gas emissions. It’s certainly something you can imagine the Trump administration doing, I posed to Yedvab.
Yedvab acknowledged that it is a “valid argument.” But the world is so off-track in meeting its goals, he said, that it needs to prepare a Plan B. He asked me to imagine two different scenarios, one where the world diligently develops the technology and governance needed to deploy solar geoengineering over the next 10 years, and another where it wakes up in a decade and decides to crash toward solar geoengineering. “Now think which scenario you prefer,” he said.
Perhaps Stardust will not achieve its goals. Its proprietary particle may not work, or it could prove less effective than sulfates. The company claims that it will disclose its particle once it receives its patent — which could happen as soon as next year, Yedvab and Spector said — and perhaps that process will reveal some defect or other factor that means it is not truly biosafe. The UN may also try to place a blanket ban on geoengineering research, as some groups hope.
Yet Stardust’s mere existence — and the “free driver” problem articulated by Barrett nearly two decades ago — suggests that it will not be the last to try to develop geoengineering technology. There is a great deal of interest in SRM in San Francisco’s technology circles; Pastzor told me that he saw Reflective as “not really different” from Stardust outside of its nonprofit status. “They’re getting all the money from similar types of funders,” he said. “There is stuff happening and we need to deal with it.” (A Reflective representative disputed this characterization, saying that the nonprofit publishes its funders and has no financial incentive to support geoengineering deployment.)
For those who have fretted about climate change, the continued development of SRM technology poses something of a “put up or shut up” moment. One of the ideas embedded in the concept of “climate change” is that humanity has touched everywhere on Earth, that nowhere is safe from human influence. But subsequent environmental science has clarified that, in fact, the Earth has not been free of human influence for millennia. Definitely not since 1492, when the flora and fauna of the Americas encountered those of Afro-Eurasia for the first time — and probably not since human hunters wiped out the Ice Age’s great mammal species roughly 10,000 years ago. The world has over and over again been remade by human hands.
Stardust may not play the Prometheus here and bring this particular capability into humanity’s hands. But I have never been so certain that someone will try in our lifetimes. We find ourselves, once again, in the middle of things.
Editor’s note: This story has been updated to include a response from the Reflective team.
Much of California’s biggest county is now off limits to energy storage.
Residents of a tiny unincorporated community outside of Los Angeles have trounced a giant battery project in court — and in the process seem to have blocked energy storage projects in more than half of L.A. County, the biggest county in California.
A band of frustrated homeowners and businesses have for years aggressively fought a Hecate battery storage project proposed in Acton, California, a rural unincorporated community of about 7,000 residents, miles east of the L.A. metro area. As I wrote in my first feature for The Fight over a year ago, this effort was largely motivated by concerns about Acton as a high wildfire risk area. Residents worried that in the event of a large fire, a major battery installation would make an already difficult emergency response situation more dangerous. Acton leaders expressly opposed the project in deliberations before L.A. County planning officials, arguing that BESS facilities in general were not allowed under the existing zoning code in unincorporated areas.
On the other side, county officials maintained that the code was silent on battery storage as such, but said that in their view, these projects were comparable to distribution infrastructure from a land use perspective, and therefore would be allowable under the code.
Last week, the residents of Acton won, getting the courts to toss out the county’s 2021 memorandum allowing battery storage facilities in unincorporated areas – which make up more than 65% of L.A. County.
Judge Curtis Kin wrote in his October 14 ruling that “such expansive use of the interpretation runs contrary to the Zoning Code itself,” and that the “exclusion” of permission for battery storage in the code means it isn’t allowed, plain and simple.
“Consequently, respondents and real parties’ reliance on the existence of other interpretive memos and guidance by the [Planning] Director is beside the point,” Kin stated. “There is no dispute the Director has the authority to issue memos and interpretations for Zoning code provisions subject to interpretation, but, as discussed above, such authority cannot be used in such a way as to violate the provisions of the Zoning Code.”
The court also declared the Hecate project approval void and ordered the company to seek permits under the California Environmental Quality Act if it still wants to build. This will halt the project’s development for the foreseeable future. Alene Taber, the attorney representing Acton residents, told me she has received no indication from Hecate’s legal team about whether they will appeal the ruling.
Hecate declined to comment on the outcome.
Taber’s perspective is unique as a self-described “rural rights” attorney who largely represents unincorporated communities with various legal disputes. She told me this ruling demonstrates a serious risk regulators face in moving too fast for a host community, especially given rising opposition to battery storage in California. Since the Moss Landing fire, opposition to storage projects has escalated rapidly across the state – despite profound tech differences between more modern designs proposed today and the antiquated system that burned up in that incident.
I asked Taber if she thought California enacting a new law last week to beef up battery fire safety oversight could stem the tide of concerns about battery storage. In response, she railed against a separate statute giving energy companies – including battery developers – the ability to work around town ordinances and moratoria targeting their industry.
“Even though the county didn’t consider the community input — which it should’ve — the county process at least still allowed for communities to appeal the project. And they’re also at least supposed to consider what the local zoning code said,” Taber told me. “Local communities are now sidelined all together. They’re saying they don’t care what the concerns are. Where’s the consideration for how these projects are now being sited in high fire zones?”
I was unable to reach Los Angeles County officials before press time for The Fight, but it’s worth noting that, amid the battle over Hecate’s approval, L.A. County planning officials began preparing to update their renewable energy ordinance to include battery storage development regulation – an indication they may need new methods to site and build more battery storage. There’s no timeline for when those changes will take place.