Private companies are starting to change the way we think about climate solutions. The focus has shifted from government programmes and international initiatives to the involvement of start-ups and non-profit organisations in the risky endeavour of "cooling" the planet.
Two basic technologies are at the centre of attention. The first involves injecting particles into the stratosphere to reflect some of the sun's radiation and thus temporarily lower the temperature. This method is called Stratospheric Aerosol Injection, or SAI.
The second branch involves the direct removal of carbon dioxide from the air, known as Carbon Dioxide Removal (CDR) or Direct Air Capture (DAC).
Private companies currently tend to favour the first method because it promises visible effects in a short time, but this is precisely where the main pitfall lies.
One of the most closely guarded start-ups in this field is called Stardust Solutions. It was registered in the United States and Israel and went public in February 2025.
The company's name appeared in a report by the Centre for International Environmental Law (CIEL) because its plans would almost certainly violate the Convention on Biological Diversity's moratorium banning the experimental modification of atmospheric chemistry.
Stardust officials say they initially intend to use special aircraft to disperse small mineral particles into the atmosphere at an altitude of 20 kilometres. This substance would reflect some of the sun's rays back into space and temporarily lower the global temperature.
Reports from March indicate that Stardust has raised almost 15 million dollars in venture capital, but at the same time, the origin of some of the funds remains unclear. Critics warn that it could lead to unpredictable disruptions in rainfall patterns and shifts in monsoons.
“Cooling the Earth” and strict protocols
Another ongoing project is called Make Sunsets. Their headquarters are in the southern US, and despite their talent for marketing their idea of "cooling the Earth", there is growing evidence that they do not have the necessary permits.
In January, they announced a plan to use large balloons to launch sulphur dioxide into the lower stratosphere over the western US. This gas would act similarly to a volcanic eruption and temporarily block some of the sun's radiation.
However, in April, the US Environmental Protection Agency (EPA) asked Make Sunsets to stop all preparations, as they had not submitted a single application for the emission of polluting gases into the stratosphere.
Private "climate heroes" cannot override sovereign borders and international agreements
In parallel, in March, the Mexican authorities imposed a complete ban on all forms of solar aerosol injection on their territory after several unauthorised attempts to conduct an experiment over Baja California.
With this step, Mexico wanted to send a message to the whole world: private "climate heroes" cannot override sovereign borders and international agreements.
In contrast to the risky Solar Radiation Management (SRM) projects, there is a non-profit organisation Arctic Ice Project in the United States.
Its Ice Bright initiative focuses on increasing the reflection of polar clouds with the help of calcium carbonate particles.
This is not injected directly into the stratosphere but targets the cloud cover over the Arctic to slow down the melting of sea ice.
However, in early February, it was announced that the AIP was suspending all tests after scientists pointed out the risk of changes to ocean circulation and potential disruption to the food webs of polar ecosystems.
Although the AIP is formally a non-profit organisation, in reality, it is supported by foundations with large Silicon Valley funds that want results as quickly as possible. This pressure from private funders often bypasses strict academic and government protocols.
Blurred line between public and private
Mixed signals are coming from Europe. At the end of April the British Advanced Research and Invention Agency (ARIA) provided around £ 56.8 million to fund a series of geoengineering experiments in the UK.
This money is earmarked for projects that will boost cloud formation with salt water, test new ways to preserve Arctic ice and trials with aerosols in smaller geographic areas.
The partners include several companies that have emerged from university workshops whose aim is to commercialise the technology at a later stage.
In practice, this means that the line between public and private is becoming increasingly blurred as taxpayers' money mixes with venture capital investment and academic aspirations.
Technology can become a tool of political blackmail or an unofficial race to control the climate
Financial support for geoengineering ranges from tens of millions of dollars to hundreds of millions.
The Quadrature Foundation and the Pathfinder Foundation have provided significant funding through the Solar Radiation Management Governance Initiative (SRMGI). According to the latest SRMGI report from January, no fewer than 37 projects in 22 countries have been supported.
Their aim is not so much to run a pilot project themselves but rather to help local authorities understand the impact of SAI methods and overcome potential risks.
However, reports indicate that most project teams come from the private sector rather than government or multilateral organisations.
Such a model provides money and industrial expertise but, at the same time, removes what some have called a "moral mirror"—the awareness that technology can become a tool of political blackmail or an unofficial race to control the climate.
SRM approaches and global monitoring
Technically, SRM approaches are based on the idea that it is possible to lift particles that reflect the solar spectrum into the atmosphere.
Stratospheric aerosol injection (SAI) assumes that it is sufficient to disperse sulphur dioxide or other mineral particles in a layer of the atmosphere that is more than 20 kilometres away.
A study by the University of London (UCL) in April 2025 estimated that the cost of a single mission using customised aircraft would be between 20 and 30 million dollars, depending on the amount of substance released.
Another method, known as Marine Cloud Brightening (MCB), aims to disperse microscopic particles over the ocean using ships or drones. They would make clouds more reflective and act locally at tropical and subtropical latitudes.
Both technologies seem attractive, as they can cause relatively rapid cooling. However, scientists warn that the lack of global monitoring could lead to unforeseen consequences.
It has already been noted that uniform or uneven application of SRM could disrupt monsoon routines in Asia and Africa and cause difficulties for agriculture in areas dependent on stable weather rhythms.
No one wants to take direct responsibility for potentially massive damage caused by the experimental dispersal of particles across borders
The legal framework for geoengineering is not yet fully defined. The UN Convention on Biological Diversity (CBD) indirectly calls for a moratorium on SAI methods but has no legal force without additional protocols.
The European Commission will not start considering proposals for the introduction of ethical and technological standards until early summer 2025, but it is clear that no one wants to take direct responsibility for potentially massive damage caused by the experimental dispersal of particles across borders.
The US Congress has still not passed specific legislation to control the release of gases such as sulphur dioxide into the stratosphere.
The EPA is the only agency that has responded to Make Sunsets, but it has no mechanism for global enforcement of legal standards.
Mexico has enacted a total ban on geoengineering experiments on its territory, but that only affects local start-ups, while global "flying labs" can operate in international airspace.
Moral hazard – the biggest concern
The moral hazard is one of the biggest concerns. If it becomes common to buy or sell "cold credits" based on projects of dispersing substances, governments and industries may think they can "skip" the difficult process of reducing greenhouse gas emissions quickly enough.
In May, Science warned that the very idea of geoengineering could ease the pressure on the transition to renewable energy sources and energy efficiency.
Put simply, the ongoing debate over experimental flights and simulations could potentially postpone crucial decisions regarding transitioning away from fossil fuels.
Political tensions are also increasing. Imagine a situation where a company from one country starts dispersing particles into the stratosphere, while a neighbouring country suffers from less rainfall and more difficult agriculture.
Such conflicts can become a source of new tensions and are a threat to international stability.
Some countries are in favour of establishing special bodies within the UN Climate Change Conference (UNFCCC) to monitor any trials or commercial applications of geoengineering technologies
This is why some countries are in favour of establishing special bodies within the UN Climate Change Conference (UNFCCC) to monitor any trials or commercial applications of geoengineering technologies.
The debate continues over whether the body should have the authority to halt illegal projects or merely issue recommendations.
A combination of scientific estimates and political relations suggests that there will be more attempts by private companies to test local pilot projects in the coming months.
Stardust Solutions announced in May that instead of actual dispersing, they will be using drones to drop inert mineral powders over the Indian Ocean to collect data without emitting sulphur dioxide.
In doing so, they hope to avoid accusations of violating international standards and prove that the effects on the climate can be monitored without actually harming the atmosphere.
If all the measurements show that it is possible to predict the behaviour of the particles and assess the risks, the next step would be to emit "real" aerosols.
Once the habit of conducting such tests emerges, it creates an opportunity for competitive geoengineering in the most sensitive areas.
In the absence of global rules, different companies and countries could potentially engage in a race to apply geoengineering in the most sensitive parts of the world.
Developing a hybrid model
In addition to particle dispersion methods, private investors are also increasingly looking at CDR technologies.
Carbon Engineering from Canada and Climeworks from Switzerland are pioneers in the direct removal of CO₂ from the air.
They do not change the feeling that the world is "cooler" and have no immediate effect, but they can generate credits that are sold to large companies as proof that a certain amount of carbon has actually been removed.
In June 2025, the cost of removing a tonne of carbon dioxide through the DAC process is between $600 and $800, meaning that small CDR start-ups cannot easily compete as they need a stable source of cheap energy.
Western governments, including those in the US and Europe, have announced tax incentives for such projects, but it is uncertain whether the market will develop fast enough to meet the growing demand for zero emissions.
Innovative technologies or maintaining the status quo while global emissions continue to rise?
The forecast for the next two years shows that private geoengineering will continue to develop in the direction of a hybrid model.
Merely dispersing the particles and cancelling the tests will not be sufficient. Safety regulations will require start-ups to partner with academic centres to gain access to simulations and precise measurements.
Insurance models must simultaneously prepare for the possibility that a single experiment could abruptly disrupt regional climate patterns.
Governments will be faced with a dilemma: should they enable innovative technologies that promise a temporary reduction in temperatures or maintain the status quo while global emissions continue to rise?
A tool or a weapon?
If there is no agreement under the UNFCCC and the Convention on Biological Diversity, it is possible that a few countries will form a bloc to support private initiatives.
As long as there is no unified global policy, there is a risk that a kind of race in geoengineering will be set in motion, with each participant trying to gain local advantages while neglecting the overall environmental and social interest.
An alternative to such chaos is the creation of a mechanism similar to the World Trade Organisation or the International Atomic Energy Agency (IAEA)
The pressure could eventually turn against the participating countries themselves, as unpredictable changes in precipitation distribution could disrupt agriculture, water supplies and population stability.
An alternative to such chaos is the creation of a mechanism similar to the World Trade Organisation or the International Atomic Energy Agency.
An institution is needed that has the power to take corrective action and require private companies to submit all relevant data before even a symbolic evolutionary mission is undertaken.
The misuse of scientific research and industrial patents can easily occur in the absence of such a body. At best, experiments will be conducted at low altitudes over oceans and far away from densely populated areas. At worst, the Earth could actually face changing rainfall patterns that will trigger an even greater wave of migration and political conflict.
Private geoengineering emerges as the solution to urgent action as the world strives to reduce emissions and transition to clean energy.
However, the solution must not exacerbate the problem. If the global community fails to establish a clear legal and scientific framework, history demonstrates that even the most well-intentioned journey can lead to disastrous outcomes.
That is why it is crucial that governments, non-governmental organisations and private individuals join forces now and develop a responsible approach, because only then can geoengineering become a tool and not a weapon that causes irreversible change on the planet.
