They Want to Dim the Sun, But They Still Cannot Answer the First Question
A private geoengineering startup has raised tens of millions of dollars to develop technology that could one day be used to dim sunlight reaching Earth. That sentence alone should stop every thinking person in their tracks.
The company is Stardust Solutions, an Israeli-US startup working on solar radiation modification, also called solar geoengineering. The basic concept is to release reflective particles high in the atmosphere so a portion of sunlight is bounced away from the planet. Supporters say this could cool Earth while governments struggle to reduce emissions fast enough. Critics say it is a reckless planetary experiment with no proper global consent, no settled governance, and no reliable way to predict the full consequences. Stardust reportedly raised US$60 million in a major funding round in 2025, with total capital raised reported at around US$75 million.
This is not fringe science fiction anymore. This is venture capital moving into the machinery of the sky.
The most alarming part is not only the idea of reflecting sunlight. It is that Stardust is developing a proprietary particle and has not yet publicly disclosed what it is. Its CEO Yanai Yedvab has said the company plans to reveal more about the particle “in the coming months,” while the company has promoted the idea of a particle that could be produced at large scale and be safer than sulphate aerosols.
But that does not answer the first question.
Who gave any private company the moral right to design material for release into the shared atmosphere?
For decades, solar geoengineering has been discussed mostly by academics, climate modellers, policy groups and government-linked institutions. Even there, it has remained controversial. The risks are not small. Injecting reflective material into the stratosphere could alter rainfall patterns, affect agriculture, create regional winners and losers, disturb atmospheric chemistry, and introduce a new geopolitical weapon of leverage. If one nation benefits and another suffers drought, who decides whether the program continues?
"This is the central problem. Geoengineering is not just a technology question. It is a sovereignty question. It is a food security question. It is a health question. It is a consent question".
Bronwyn Holm*
The usual comparison is volcanic eruption. Large volcanic eruptions can cool global temperatures for a period because sulphate particles in the stratosphere reflect sunlight. But sulphates can also contribute to ozone depletion and acid rain concerns, which is why companies like Stardust are trying to find something else. The problem is that “something else” is still not publicly known in detail.
So the public is being asked to accept a strange bargain.
Trust us. We are developing a secret particle. It may one day be released into the sky.
It is for your own good. And yes, there is a business model attached. That should not be good enough.
The history of this field already shows why people are right to be wary. In 2023, Mexico moved against solar geoengineering experiments after the startup Make Sunsets released sulphur dioxide using weather balloons in Baja California. Mexico said the launch violated national sovereignty.
Harvard’s own high-profile SCoPEx project, which aimed to study stratospheric particle behaviour, was cancelled in 2024 after years of delay, scrutiny and public opposition. The planned experiment would have involved releasing a small amount of particles, primarily calcium carbonate, from a high-altitude balloon, but even that smaller research project ran into serious governance and consent problems.
That matters because if a university research project struggled to pass the public trust test, why should a private venture-backed company be allowed to move faster?
The answer from industry is usually that climate change is urgent. That is true. Heat, drought, flood, crop failure and ecological stress are real. But urgency is also the oldest sales script in the world. Urgency can be used to push good action, and it can be used to push dangerous shortcuts.
The Earth is not a lab bench. The sky is not a private patent field. And sunlight is not a commodity to be managed by whoever raises the largest funding round.
The deeper issue is the same pattern we keep seeing across food, medicine, energy and data. First, a crisis is allowed to grow. Then, instead of repairing the living systems that have been damaged, a technical control system is proposed. Then private capital builds the tool, claims benevolence, and waits for government or international bodies to become the customer.
That is not stewardship. That is control architecture.
Real climate repair should begin where life actually functions. Soil. Water. forests. grasslands. wetlands. local food systems. microbial systems. farming systems that hold carbon, retain water, cool landscapes, and rebuild resilience from the ground up.
****Healthy soil does not just grow food. It buffers heat. It holds water. It supports plant transpiration. It creates cooler local microclimates. It reduces erosion. It helps landscapes absorb shock. This is the kind of climate work that strengthens life rather than placing a chemical veil between Earth and the sun.
No one is saying soil alone solves every planetary problem. But there is a world of difference between restoring living systems and engineering atmospheric dependency.
Once a solar dimming program begins at scale, stopping it may become politically and physically difficult. If temperatures are artificially suppressed while greenhouse gases remain high, suddenly stopping could cause rapid warming. That is one of the known concerns in geoengineering debates. It creates a dependency trap. The world becomes hooked on the intervention.
That is why governance cannot be an afterthought.
It is not enough for companies to publish guiding principles. It is not enough to say they hope governments will regulate them later. The public has heard that language before. “Safe.” “Transparent.” “Responsible.” “Necessary.” “For the future.” These are pleasant words, but pleasant words do not neutralise planetary risk.
The question is brutally simple.
Before anyone releases reflective particles into the shared atmosphere, the world deserves to know:
What exactly is the particle? Who tested it? Who owns the patent? Who profits?
Who gives consent? Who monitors harm? Who pays if rainfall shifts, crops fail or ecosystems are affected? Who has the power to say no?
Until those questions are answered openly, solar geoengineering should not be treated as heroic innovation. It should be treated as a warning sign.
Because when private companies begin designing tools to dim the sun, humanity is no longer just discussing climate policy.
We are discussing who gets authority over the sky. And that will end in tears.
Can a Hail Mary stave off climate change by dimming the Sun? Now it is serious no longer cheap talk......
The UK Has Now Stepped Into the Sun-Dimming Arena
The private sector is not the only one moving toward solar geoengineering. The United Kingdom has now become one of the world’s major public funders of climate-cooling research.
The UK’s Advanced Research and Invention Agency, known as ARIA, has launched a £56.8 million Exploring Climate Cooling program to investigate whether climate cooling approaches could ever be “feasible, scalable, safe, and governable.” The agency says the program is designed to build an evidence base, not to deploy the technology.
But the experiments being discussed are not small in ethical meaning, even if they are technically described as small-scale.
ARIA-backed research includes work on solar radiation modification, marine cloud brightening, stratospheric particles, Arctic sea ice thickening, modelling, governance, ethics, and environmental monitoring. The Guardian reported that the program includes real-world experiments such as testing sun-reflecting particles, brightening clouds with seawater sprays, and pumping water onto sea ice to thicken it.
That means the question has changed.
This is no longer simply, “Should a private company be allowed to design a proprietary particle to dim the sun?”
It is now also, “Should governments begin funding the physical testing of technologies that alter sunlight, cloud behaviour, ice reflection, and atmospheric systems?”
ARIA argues that the missing piece is real-world physical data. Its program director, Mark Symes, has said that the risk of climate tipping points has increased interest in approaches that might cool the world quickly, and that researchers need real-world data to understand whether those approaches are viable. The agency also says the work will include independent oversight, environmental impact assessments, community engagement, and governance research.
That sounds careful. But careful does not mean harmless.
The British government itself has previously stated that reducing greenhouse gas emissions and protecting natural carbon sinks remain the priority, and that solar radiation modification would not reverse problems such as ocean acidification.
That point matters. Dimming sunlight does not remove carbon dioxide from the atmosphere. It does not rebuild soil. It does not clean water. It does not restore forests. It does not fix ocean acidification. It does not repair the broken relationship between industrial systems and the living planet.
At best, solar geoengineering is a temporary mask over one symptom: temperature.
At worst, it becomes a planetary dependency system.
The “Hail Mary” Problem
The language around solar geoengineering is becoming very predictable.
We are told the climate crisis is urgent, the tipping points may be close, emissions cuts are too slow, and we need every tool available.
Then we are told the only responsible thing is to begin testing technologies that alter the sky. That is the Hail Mary argument.
It is emotionally powerful because it sounds practical. If the house is burning, why not test every hose? But the sky is not a hose.
Solar radiation modification is not simply another climate tool. It is a technology class that could affect rainfall, regional weather, food production, atmospheric chemistry, and geopolitical power.
The Royal Society has warned that solar radiation modification carries potential risks and detrimental impacts, even while assessing possible climate benefits.
This is where the debate becomes blunt.
Who gets cooled? Who gets drought? Who gives consent? Who monitors the damage? Who controls the switch? Who pays if the experiment helps one region and harms another?
A global thermostat is not a neutral invention.
The Shipping Lesson They Do Not Want to Talk About
One of the most revealing recent climate findings came not from a laboratory but from shipping regulation.
When international rules reduced sulphur pollution from ship fuel, the air over shipping lanes became cleaner. That was good for human health. But it also reduced the reflective aerosol haze that had been bouncing sunlight away.
Several studies have examined whether this cleaner air contributed to a recent jump in warming. The debate is still active, but the lesson is ugly either way: aerosols can cool, but they are also pollution. Removing them may reveal hidden warming. Adding them deliberately creates a new form of dependence. That is the trap.
If humanity begins relying on reflective particles to suppress heat while greenhouse gases remain high, stopping the program later could cause rapid warming. This is often called “termination shock” in geoengineering debates.
In plain English: once you start dimming the sun, you may have to keep doing it.
That is not climate repair but climate medication with withdrawal symptoms!!
The Better Question
The better question is not, “Can we dim the sun?”
The better question is, “Why are we so willing to engineer the sky while refusing to repair the ground?”
Healthy soil cools landscapes. Living plants move water. Forests create shade and rainfall patterns. Wetlands buffer floods. Grasslands hold carbon. Microbial systems make nutrients cycle. Regenerated landscapes reduce heat stress at ground level in the places where people, animals and food crops actually live.
This is not romantic notions. It is practical climate resilience.
Solar geoengineering looks upward and asks, “How do we control sunlight?”
Living-system repair looks downward and asks, “How do we restore the planetary systems that used to buffer heat, water, carbon and life?”
One path creates dependency on technical governance. The other rebuilds biological intelligence.
A Fair Bottom Line
Could solar geoengineering cool the planet temporarily?
Possibly. Volcanic eruptions have shown that particles in the stratosphere can reduce global temperatures for a period. That is why the idea exists.
But could it safely, fairly and governably protect life on Earth? That is far from proven. And until that question is answered, every “small experiment” should be treated as part of a much larger moral crossing.
Because once governments and private companies begin experimenting with the reflection of sunlight, the public is no longer just watching climate science.
We are watching the early architecture of climate control. Control - profiting from the misery of others.