Vast sums of private and public money are now chasing a once-fringe idea: deliberately reflecting a slice of sunlight back into space to cool a dangerously overheating planet. The multimillion-dollar push to dim the sun is moving faster than the rules meant to govern it, creating a collision between venture-backed speed and planetary-scale risk. I see a field that is no longer hypothetical science fiction but an emerging industry, with real companies, real experiments and real political stakes.
From wild idea to serious climate lever
Solar geoengineering, often shortened to Solar or SRM, has shifted from academic thought experiment to a live option in climate policy circles. Researchers now describe solar geoengineering (SG), also known as solar radiation management or SRM, as a set of large scale interventions that would reflect more sunlight away from Earth to reduce warming, a concept that even its advocates concede is double edged because it could cool temperatures while introducing new risks to weather patterns and ecosystems, as outlined in detailed Solar analysis. I find that framing crucial, because it captures both the appeal of a fast acting climate lever and the fear that tinkering with planetary physics could backfire in ways we barely understand.
Governments are starting to treat this as a real policy domain rather than a taboo, even as they stress that cutting emissions must remain the main tool. In the United States, officials have begun developing a federal research plan for solar geoengineering, with a specific goal of helping researchers in regions that are especially vulnerable to climate change play a greater role in shaping which approaches are studied and how, according to a Jun program description. That shift, from ignoring the idea to cautiously organizing it, is what has opened the door for both public labs and private startups to race ahead.
The experimental toolkit to cool the planet
Behind the rhetoric about dimming the sun sits a concrete toolbox of techniques that scientists are now testing in the lab and, increasingly, in the open air. One of the most discussed options is stratospheric aerosol injection, in which aircraft or balloons would release reflective particles high in the atmosphere to scatter sunlight, a method that a recent policy paper on who could deploy such systems describes as one of several prospective climate technologies that could manage the solar radiation entering the Earth system, with particular attention to how major powers like the United States and China might handle Among these tools. Earlier this year, a government funded stratospheric experiment became one of the first outdoor solar geoengineering trials to receive public money, with researchers planning to release particles and then measure how they spread and reflect light over distances of up to a metre, a cautious but symbolically significant step described in a recent stratospheric report.
Other approaches focus on clouds and oceans rather than the upper atmosphere. In the United Kingdom, public funding is backing five geoengineering trials, including Marine cloud brightening, which seeks to make clouds over the ocean more reflective by turning seawater into a fine spray that seeds brighter cloud droplets, with further work contingent on additional approval by the innovation agency Aria, according to a detailed overview of Marine projects. At the same time, climate modelers such as Dr Fitzgerald are using sophisticated Earth System Models to explore how different SRM approaches might cool the planet under various temperature targets, with new funding supporting simulations that will run into the beginning of 2026 to map potential benefits and side effects of Dr Fitzgerald and colleagues’ work.
Startups, “cooling credits” and the profit motive
While national labs refine models, a new class of startups is trying to turn planetary cooling into a business. Companies like Stardust Solutions and Make Sunsets pitch themselves as nimble innovators that can move faster than governments, with Stardust Solutions explicitly saying it wants to dim the sun, a stance that has prompted concern from Scientists who warn that commercial incentives could outrun the science, as highlighted in a recent profile of Stardust Solutions. Another startup, Make Sunsets, has already launched 147 balloons and sold 128,000 “cooling credits” that it claims offset the warming equivalent to the release of 128 units of carbon dioxide, according to company figures cited in an investigation of Make Sunsets. I see those numbers as a sign that the market is already treating atmospheric manipulation as a commodity, even before regulators have decided whether such claims are scientifically or ethically acceptable.
Investors are following the money, turning what was once a niche into a budding sector. Reporting on this emerging industry notes that Make Sunsets has raised more than $1 million from investors and sold more than $100,000 worth of services, positioning itself as a contractor that can release reflective particles whenever a client hires them to do so, a model that underscores how quickly geoengineering is becoming a private industry. Critics argue that “Cooling credits” and other for profit geoengineering ventures are what inevitably emerge when climate policy is constrained by market logic, warning that such schemes risk entrenching a carbon intensive economy rather than transforming it, a concern spelled out in a recent analysis of Cooling markets.
Even within the scientific community, there is unease about how commercial money is shaping the research agenda. Two researchers have argued that the growing commercial push into solar geoengineering is bad for science and public trust, warning that when private capital sets the pace, experiments may be designed to serve investors rather than the public interest, a tension they explore in a critique titled Why the for profit race into solar geoengineering is bad for science and public trust, which lays out how this dynamic could distort Why the for evidence. That critique echoes a broader pattern seen in other energy transitions, where the regime responsible for most activity, such as research departments of large companies and universities, coexists uneasily with smaller actors in the micro layer that present interesting developments but may not be aligned with long term public goals, a dynamic described in work on new environmental policy for system innovation that examines how such regimes and niches interact in the shift away from fossil The regime fuels.
Who gets to touch the global thermostat
As money and experiments multiply, the most basic questions about authority remain unresolved. Even the research community is divided over who will launch geoengineering interventions, who will oversee and monitor them and who will have the power to stop them if things go wrong, with critics warning that governance is lagging far behind the technical momentum, according to a detailed account that asks Who will decide. A separate policy analysis on stratospheric aerosol injection notes that among several prospective climate technologies that could manage solar radiation, the ability of large states such as the United States and China to act unilaterally raises the risk of geopolitical tension if one country decides to cool the planet in ways that others see as harmful, a scenario that the Earth focused paper explores in depth.
Some researchers are trying to build governance into the science itself. The Harvard Solar Geoengineering Research Program, for example, emphasizes that There are several proposed solar geoengineering technologies, including marine cloud brightening, cirrus cloud thinning and space based reflectors, and that any research agenda must consider how these methods would reflect more sunlight back into space while remaining accountable to society, a balance the program describes in its overview of There initiatives. At the same time, some climate policy experts argue that deployment decisions should be left to governments, and that scientists should focus on studying risks and benefits so elected leaders and civil society can decide whether any intervention is in the best interest of the planet, a principle laid out in guidance that stresses how Deployment choices must not be outsourced to private actors.
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