Dimming the Sun to Save the World
Stardust CEO Yanai Yedvab on Using Nature To Prevent a Climate Catastrophe
Yanai Yedvab thinks we need to completely overhaul the infrastructure of humanity to avoid a climate disaster, and we can’t afford to wait the 70 years it’ll take to wean off fossil fuels. Before founding Stardust, Yanai spent nearly three decades in Israeli nuclear research, ending up as deputy chief scientist at the Israel Atomic Energy Commission.
Stardust is developing reflective particles to disperse into the upper atmosphere that will buy us the several decades we need to transition into a low-carbon economy. We sat down in New York to talk about how the technology works, the dangers at stake if we do nothing, and Yanai’s radical optimism in spite of everything.
Watch the full episode here:
Solving the Climate Crisis Requires Changing the Infrastructure of Humanity
As Yanai puts it, for every ton of anything humanity produces, we emit roughly one ton of greenhouse gases. From processing raw materials, food, transportation, and electricity, virtually every significant human activity is connected to greenhouse gas emissions. The result is that roughly 1,000 billion tons of greenhouse gases now sit in the atmosphere, a number roughly comparable to the total mass of everything humanity has ever built.
To transition to a low-carbon economy, you would need to replace essentially all of that infrastructure. Yedvab’s honest estimate for how long that takes: 50 to 70 years.
This is the reason he is not building a solar panel company.
“Continuing to do what we’ve been doing over the last few decades and expecting materially different results,” he says, “unfortunately will not get us there.”
The climate movement’s original strategy - educating people, changing behavior, deploying renewables - was unrealistic. And ridiculing anyone who questioned “the science” is what led to the reactionary movement that elected Trump.
Any successful movement will have to seriously reckon with the infrastructure timescale, as well as a way of buying time for the economic transformation away from fossil fuels to take place.
Enter Stardust.
What Volcanoes Taught Us About Cooling the Planet
In 1991, Mount Pinatubo erupted in the Philippines, launching fifteen million tons of sulfur dioxide into the stratosphere. For the following 18 months, global temperatures dropped by 0.4 degrees Celsius.
This is the proof of concept that Yanai and his co-founder Amyad Spetor seized on when they came across a 2021 National Academy of Sciences report making the case for solar reflection technology (SRT). The science was not in question: we now know that small particles dispersed in the upper atmosphere can reflect a tiny portion of sunlight to cool the planet in a reversible manner. The question was whether you could do it deliberately, safely, and in a way that policymakers might actually get behind.
The problem with sulfur dioxide, the material volcanoes use, is that it is also a toxic substance that induces acid rain, damages the ozone layer, and carries a long list of other side effects. It is, as Yanai puts it, “a nonstarter for any reasonable person.”
Stardust is developing a new particle designed to meet an excruciatingly demanding safety checklist: effective at reflecting sunlight, manufacturable at scale, biodegradable, and safe enough to qualify as a food ingredient. When the particle eventually falls to Earth, it will re-enter natural biological cycles rather than accumulate in ecosystems.
One gram of these particles dispersed in the upper atmosphere will offset the warming effects of one ton of greenhouse gas emissions.
The Montreal Protocol as a Template for International Cooperation
Yedvab is aware that “trust us, we’ve got a particle” is not a governance framework. With his background at the intersection of technology and policymaking, this was at the forefront of his mind when incorporating Stardust.
In the 1980s, a US-led coalition of government, academia, and industry worked together - under the Reagan Administration(!) - to develop alternatives to the chlorofluorocarbons eating away at the ozone layer. You don’t need to be a Democrat to care about the future of humanity.
The middle of the Cold War gave rise to the greatest success in the history of environmental diplomacy: The Montreal Protocol.
“A sense of urgency and courage and leadership” made this possible, Yanai rightly states.
At some point in the near future, Stardust will be waiting when humanity really begins to feel the effects of climate change. We are going to collectively have a realization Apollo Astronaut Edgar Mitchell had when gazing back at Earth from the moon :
From out there on the moon, international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, ‘Look at that, you son of a bitch.’
Peter Thiel will metamorphosize into Greta Thunberg during the next vibe shift, and the venture dollars will follow in droves.
Yanai points out that Stardust sees itself only as enabling the SRT solution, but not the entity that will decide whether to deploy it. That decision must remain with world governments. The technology exists to enable a choice, not to make one. Stardust has explicitly issued what amounts to a moratorium on self-deployment.
Unexpected Benefits of Solar Reflection Technology
When I asked him about other worthy climate quests people might want to work on, Yanai got very excited about the possibility that Stardust’s atmospheric monitoring infrastructure - the vast network of measurements the deployment system would generate - could help us dramatically improve weather prediction.
Edward Teller and others pointed out that the limiting factor on predicting the weather isn’t our understanding of physics, but the scarcity of data.
With an abundance of new data, he thinks we may be able to extend the horizon for accurate weather forecasting from five days to two weeks, which would be a paradigm shift for agriculture, natural disaster response, and dozens of other domains.
Yanai’s Greatest Concern for 2050
It is not, surprisingly, a scientific one.
What concerns Yanai most is the difference between facing a crisis in ‘emergency mode’ versus having built the infrastructure in advance to respond to that crisis.
His hero here is the late Prime Minister of Israel, Yitzhak Rabin, who, thirty years before the threat materialized, mandated that every building in Israel have a shelter and partnered with the US to build a missile defense system. Rabin didn’t know what specific threat he was preparing for, but that wasn’t the point.
Yedvab is building something analogous for the climate crisis: not a response assembled in panic when the tipping point arrives, but a ready system that governments can activate with confidence because the research has been done.
His worry is that we will procrastinate until it is almost too late to do this work carefully. Emergency mode produces bad decisions. A mature technology that policymakers understand, developed transparently and validated through years of published research, is the only version of this story that ends well.
The Transparency Bet
Yanai is betting that radical transparency is the only viable business model for a company that wants governments to deploy this technology.
Everything Stardust develops will be published, including unfavorable results. Stardust has recently published two papers detailing the safety and controllability requirements for SRT systems and guiding principles for doing ethical SRT research.
The analogy he reached for in our conversation is a cancer drug. If you are sick and someone asks you to take a medicine, you need to know exactly what it is. You need to trust that someone other than the manufacturer has looked at the data. Solar geoengineering, deployed at atmospheric scale over every living creature on Earth, requires an even higher standard of that trust.
Stardust is a private company out of practical necessity: it is the only way to attract the capital and talent that the problem demands, as the history of pharmaceuticals, genome sequencing, and space exploration all confirm.
The tipping point in the climate crisis is fast approaching. It is up to us whether we have a good answer prepared when it arrives.
I am grateful for people like Yanai whose optimism and enthusiasm will carry us through the tough times to a new world in 2050 and beyond.