A venture-backed startup wants to cool the planet with sunlight-reflecting particles. Here’s what that means for green technology, governance, and your climate strategy.
Most climate technologies promise a few percentage points of improvement. One startup is promising to turn down the global thermostat for about a billion dollars a year.
That company is Stardust Solutions, an Israel-based solar geoengineering startup that wants to cool the planet by spraying sunlight-reflecting particles into the stratosphere. It just raised $60 million, the largest known funding round in this field so far—and it’s already forcing a hard question onto the green technology table:
Are we ready for for‑profit companies to sell climate control as a service?
This matters for anyone working in climate, energy, or sustainability strategy. Green technology is no longer just solar panels, batteries, and smart grids. It now includes tools that could change the physics of the climate system itself. Used wisely, they might buy time for decarbonization. Used badly, they could trigger political chaos and public backlash that harms the entire climate agenda.
In this post, I’ll break down what Stardust is actually proposing, why many scientists are alarmed, and how responsible green technology leaders should think about solar geoengineering in the 2020s.
What Stardust Is Trying To Do—And Why It’s So Controversial
Stardust Solutions is building a commercial system for solar radiation management (SRM): dispersing particles high in the atmosphere to reflect a fraction of incoming sunlight, cooling the planet for a few years at a time.
The basic idea isn’t new. After big volcanic eruptions, sulfur dioxide in the stratosphere has temporarily cooled global temperatures by as much as 0.5 °C. SRM tries to mimic that effect in a controlled way.
Stardust’s twist is to replace sulfur with a “safe, inert” proprietary particle that it says:
- Can be manufactured cheaply at scale
- Reflects sunlight effectively
- Doesn’t damage the ozone layer
- Breaks down harmlessly
The company’s early investor materials went further, claiming its system could counteract the warming impact of 150 years of greenhouse-gas emissions and calling it the “only technologically feasible solution” to climate change.
That last claim is where many climate scientists draw a line. Solar geoengineering can mask warming; it doesn’t remove CO₂, stop ocean acidification, or fix the systemic causes of climate risk. From a green technology standpoint, it’s a risk-management tool, not a substitute for decarbonization.
Why scientists are pushing back
Researchers who actually study SRM are worried about several things:
- Pace and scale: Stardust’s early roadmap mentioned large-scale demonstrations by ~2030 and global deployment by ~2035. Experts say that’s wildly premature given current research gaps.
- Governance vacuum: There’s no global agreement on if, when, or how to use solar geoengineering. Unilateral deployment could spark geopolitical conflict.
- For-profit control: Handing the “global thermostat” to a VC-backed startup looks, to many, like a trust disaster in slow motion.
- Opacity: Claims about a “magic aerosol particle” are impossible to evaluate until methods and data are fully published.
You don’t have to be an ethicist to see the risk: if the first major deployment of SRM is perceived as a tech investor project, public trust in all advanced climate tools—AI for clean energy, carbon removal, even basic climate science—takes a hit.
How Solar Geoengineering Fits Into the Green Technology Landscape
Here’s the thing about green technology: the more effective it becomes, the more we’re forced to talk about trade-offs, not just wins.
Solar geoengineering sits at the far edge of that spectrum. It’s powerful, fast-acting, and deeply political.
Mitigation vs. management vs. manipulation
From a systems view, climate tools fall into three broad buckets:
- Mitigation – reduce emissions and increase removals (renewables, efficiency, carbon capture, regenerative agriculture). This is the core of any credible climate strategy.
- Adaptation – reduce harm from inevitable climate impacts (flood defenses, heat-resilient buildings, drought-resistant crops).
- Manipulation – directly alter climate forcing (solar geoengineering, cloud brightening, ocean fertilization).
Stardust operates in bucket 3. That doesn’t make it automatically bad, but it does mean:
- Governance has to be stronger than for most climate tech.
- Public participation matters more than usual.
- The risk of moral hazard—slowing emissions cuts because “we can cool things later”—is real.
Where AI and data come in
Because this post is part of a green technology series, it’s worth calling out the quiet hero in all of this: AI-driven climate modeling and monitoring.
If SRM is ever tested responsibly, AI and advanced analytics will be essential to:
- Simulate regional climate impacts under different SRM scenarios
- Track particle dispersion and radiative forcing in near-real time
- Detect unintended side effects on rainfall, monsoons, or extreme events
- Support transparent public dashboards showing what’s actually happening in the atmosphere
So even if you’re firmly against deployment, serious research into SRM pushes the frontier of climate data, sensing, and modeling that can benefit the rest of the green technology stack.
Inside Stardust’s Model: For-Profit Climate Control
Stardust made a deliberate choice: build as a venture-backed for‑profit company, not a university project or philanthropic lab.
The rationale is straightforward:
- Big, complex engineering platforms require tens to hundreds of millions of dollars.
- Philanthropic funding for solar geoengineering is tiny compared with other climate areas.
- Private capital can hire specialized talent and build integrated systems faster.
They’re currently developing three core components:
- Engineered particles – the secret sauce, intended to be safer and more controllable than sulfur aerosols.
- Aircraft dispersion systems – modified planes capable of releasing particles at stratospheric altitudes.
- Tracking and monitoring tools – sensors and software to follow the particles and measure climate effects.
As a business, Stardust is essentially designing a “climate service” for governments: pay an annual fee, get a reduction in radiative forcing.
The financial and political risk in the model
Most companies get this part wrong: if your revenue depends on deployment of a controversial technology, your incentives are misaligned with society’s need for caution.
Critics raise three big concerns:
- Investor pressure: Venture capital expects exits, not “options that sit on the shelf.” Even if Stardust’s founders are cautious, future boards may not be.
- Lobbying incentives: Once you’ve built the system, you have a strong reason to convince governments they need it. That’s a bad match with the level of restraint SRM requires.
- Asymmetric voice: Well-funded startups can easily out-communicate under-resourced communities—especially in the Global South—who are most vulnerable to climate side effects.
Stardust’s leadership says they’re comfortable with a scenario where the world never deploys SRM and the system is never used. Maybe. But structurally, that’s not what venture-backed climate tech is usually optimized for.
If you’re building or investing in green technology, this is a useful cautionary tale: some climate tools require governance-first business models, not growth-first ones.
The Governance Gap: Who Gets To Set the Global Thermostat?
The biggest blocker for solar geoengineering isn’t engineering. It’s governance.
There is currently no global framework that answers basic questions like:
- Who decides if SRM can be tested outdoors?
- How are vulnerable countries involved in decision-making?
- What liability exists if one region experiences drought or crop failure after deployment?
- What level of cooling is acceptable, and who defines “acceptable”?
Hundreds of academics have signed statements calling for a “non-use agreement” on SRM research and deployment, arguing that fair, inclusive global governance may simply be impossible.
Others take the opposite view: refusing to research SRM doesn’t prevent a desperate or powerful country from trying it. It just guarantees we’ll know less when that happens.
From a pragmatic green tech perspective, three governance priorities stand out:
1. Separate research from deployment
We need a clear line between:
- Basic and applied research under strong public oversight, with all results published; and
- Full-scale deployment decisions, treated as geopolitical acts, not technology purchases.
That suggests any serious SRM work should be anchored in public institutions, transparent consortia, or tightly governed public–private partnerships, not left to individual startups or nations.
2. Center the Global South
The countries that contribute least to emissions are often the most vulnerable to shifts in monsoons, rainfall, and extreme heat. Any governance structure that sidelines them is illegitimate.
For SRM to even be thinkable as part of a green technology portfolio, decision-making has to include:
- Climate-vulnerable nations across Africa, Asia, Latin America, and the Pacific
- Indigenous communities already living with climate disruption
- Civil society organizations focused on justice, not just efficiency
3. Build public literacy before crisis moments
The worst-case scenario is a panicked decision under extreme climate stress—for example, after a catastrophic multi-country heat wave. By then, calm deliberation is almost impossible.
Responsible climate leaders should support:
- Honest, accessible education on what SRM can and can’t do
- Public engagement processes before deployment is on the table
- Clear separation between SRM and emissions-reduction commitments
If SRM remains a black box, public backlash will be intense—and could spill over onto low-risk, high-benefit green technologies like renewables, storage, and AI-enabled efficiency.
What Businesses and Policymakers Should Do Now
Most organizations don’t need a geoengineering strategy tomorrow. But ignoring it completely is a mistake.
Here’s a practical way to approach solar geoengineering from a green technology and climate planning standpoint.
1. Treat SRM as a last-resort risk buffer, not a core climate plan
SRM should never appear as a substitute for emissions reduction in your planning documents, climate pledges, or net-zero roadmap.
What you can do is:
- Acknowledge that SRM research exists and may influence future climate risk scenarios.
- Stress that your strategy is built on deep decarbonization first, adaptation second.
- Keep SRM, if mentioned at all, in the category of uncertain external factors.
2. Invest attention—not money—into governance discussions
For now, the most responsible corporate and public-sector move is to:
- Monitor international debates on solar geoengineering
- Support efforts for transparent, inclusive governance frameworks
- Avoid direct investment in deployment-focused SRM ventures until:
- Particles and methods are fully peer-reviewed
- Governance structures exist
- There’s clear, global consent for even field testing
If you’re allocating capital to green technology, there are far more reliable levers—renewables, storage, efficiency, grid flexibility, nature-based solutions, AI for energy optimization—that deliver climate benefits without planetary-scale moral hazard.
3. Strengthen your core green technology stack
The best way to reduce future pressure to use SRM is to accelerate the technologies that make it unnecessary:
- Scale clean energy faster: solar, wind, geothermal, advanced nuclear where appropriate
- Deploy AI and data platforms to cut energy waste and emissions in operations
- Support carbon removal that’s transparent, verifiable, and durable
- Build adaptation into infrastructure and supply-chain planning
If, twenty years from now, a global coalition seriously considers SRM, the least-bad scenario is one where emissions are already steeply declining and clean energy dominates.
Where Solar Geoengineering Fits in the Green Tech Story
The reality is simpler than the rhetoric: solar geoengineering is a possible emergency brake, not a steering wheel.
Stardust’s arrival on the scene shows that the private sector isn’t going to wait for perfect academic consensus before building SRM tools. Whether that’s courage or hubris depends on your risk tolerance—but either way, it changes the conversation.
For people building and buying green technology today, a few principles hold:
- Don’t let speculative tools distract from the proven work of cutting emissions.
- Don’t outsource planetary-scale decisions to for‑profit entities, however well‑intentioned.
- Do support strong governance, transparent research, and public literacy—because pretending SRM doesn’t exist is the fastest path to bad decisions later.
Green technology is about more than innovation; it’s about which futures we’re willing to live with. As the climate crisis deepens through the 2030s, the temptation to reach for fast fixes will grow. The smart move now is to build a world that doesn’t have to rely on them.