The idea of deliberately cooling the planet by injecting reflective particles into the stratosphere is no longer confined to academic papers. Stratospheric aerosol injection (SAI), once a fringe concept, is attracting private capital and the attention of major powers, including the United States and China. As Washington and Beijing begin to frame atmospheric modification as a matter of national security, the capacity to intervene in the weather is emerging as a new arena of geopolitical rivalry—one that could have profound consequences for the Global South, including much of Asia.
SAI works by releasing aerosols into the stratosphere to reflect a small fraction of sunlight back into space, potentially lowering global temperatures within months. But the technology is not a cure for climate change. It does not reduce atmospheric carbon concentrations, nor does it reverse ocean acidification. Its effects could be unevenly distributed, with uncertain impacts on rainfall, agriculture, and ecosystems across different regions. For countries like India, Indonesia, or Vietnam, where monsoon patterns are critical to food security, the stakes are particularly high.
Who controls the thermostat?
The core question is governance. If a state or a private company acquires the ability to alter the atmosphere, who decides when and where to use it? Who bears the consequences if it disrupts rainfall in a neighboring country or intensifies geopolitical tensions? What if a state chooses to weaponize the technology? These are not hypothetical concerns. A foresight study by Dr. Trish Lavery of the Centre for Future Generations, titled Towards Governance of Climate Cooling Approaches, outlines four scenarios for 2036 in which the politics of atmospheric intervention become as consequential as the technology itself.
Lavery argues that existing analysis has been “scientifically sophisticated but politically simplistic.” The future of solar radiation modification (SRM) may be determined less by climate models than by who finances the technology, which governments acquire the capability, and how strategic rivals interpret each other’s intentions. The issue is no longer only whether the technology could reduce global temperatures—it is who might develop it, who would decide its use, and whose interests would shape its governance.
American policy voices are beginning to describe the ability to modify the climate as a matter of “weather sovereignty,” arguing that Washington cannot afford to leave this capability to strategic rivals. This framing is likely to resonate in Beijing, where climate and technology are already intertwined with national security. The result could be a new form of great-power competition, with the atmosphere as the contested domain.
Private capital moves in
Private companies are racing to develop SAI technologies. More than US$115 million has been committed to nine solar radiation modification startups. One US-Israeli company, Stardust, aims to be deployment-ready by 2030, pursuing a government-contractor model. Its proposed deployment program could cost over $1 billion annually, and its investors are betting that governments will eventually regard atmospheric cooling as a necessary response to the economic and political costs of climate change.
Another startup, Make Sunsets, has experimented with releasing sulfur dioxide balloons and selling cooling credits directly to retail customers, outside any recognized international regulatory framework. Other proposals involve monetizing the carbon-cycle effects of SAI through carbon markets, although the standards necessary to validate such credits remain undeveloped.
This commercialization of climate intervention raises questions that global institutions have not yet addressed. Lavery distinguishes between scientific research, technology development, and deployment-adjacent testing. Technology development involves building hardware and delivery systems without necessarily being classified as actual deployment, while deployment-adjacent testing focuses on operational readiness. No universally accepted international taxonomy or enforcement mechanism distinguishes these activities, leaving a regulatory vacuum.
Asia's stake in the atmospheric arms race
For Asia, the implications are direct. The region is home to some of the world’s most climate-vulnerable populations, from the low-lying deltas of Bangladesh to the island nations of the Pacific. A technology that could alter monsoon patterns or disrupt agriculture in one country while benefiting another would test the limits of regional cooperation. The Association of Southeast Asian Nations (ASEAN) and other regional bodies have yet to engage seriously with the governance of SRM, leaving a gap that major powers may fill unilaterally.
The recent report by Carnegie Europe, Planetary Power: Geoengineering and the New Geopolitics of Climate Intervention, highlights another dimension: the growing involvement of Big Tech, venture capital, and philanthropic networks in climate intervention. These actors may see geoengineering as a way to protect existing economic systems, influence future carbon markets, and sustain technology-intensive growth. The danger is that a technology designed to address a global problem becomes another tool for strategic advantage, with the Global South—including much of Asia—bearing the risks.
As the debate over financial flows and technology transfers intensifies, the question of who controls the atmosphere is becoming as important as who controls the data or the chips. The global expansion of semiconductor giants and the capital markets fueling AI growth are part of the same geopolitical landscape. Weather sovereignty is the latest frontier in this competition, and it is one that Asia cannot afford to ignore.
The technology may still be in its infancy, but the politics are already taking shape. Without a robust governance framework, the ability to cool the planet could become a new source of conflict, not cooperation. The question is whether the world’s powers—and Asia’s leaders—will act before it is too late.
