Keep Factually independent
Whether you agree or disagree with our analysis, these conversations matter for democracy. We don't take money from political groups - even a $5 donation helps us keep it that way.
Which U.S. states have passed laws banning solar geoengineering or stratospheric aerosol injection?
Executive summary
As of the reporting in these sources, Tennessee and Florida have enacted state laws that ban at least some forms of solar geoengineering — including language covering stratospheric aerosol injection (SAI) and "solar radiation modification" — while multiple other states have introduced bills or proposals (Kentucky, Montana, Minnesota, North Carolina, Rhode Island and others) but had not all completed enactment at the time of those reports (Tennessee: 2024; Florida: June 2025) [1] [2] [3]. Coverage shows a surge of similar proposals across many states driven partly by politics and conspiracy-linked rhetoric, even as federal agencies and scientists continue to discuss research and governance [4] [1] [5].
1. Tennessee and Florida: the two confirmed state bans
Tennessee is reported as the first state to pass a law banning intentional modification of sunlight, weather, or temperature — a statute that explicitly encompassed solar geoengineering and stratospheric aerosol injection — with coverage noting the law passed in 2024 [1]. Florida passed a law in June 2025 described as prohibiting acts intended “to affect the temperature, the weather, or the intensity of sunlight,” language that covers both solar geoengineering and traditional weather modification; the White House–related federal context was cited in state debate [2] [3].
2. Bills and proposals elsewhere: many states have tried but not all have passed laws
Reporting and advocacy trackers show bills or proposals in several other states. Examples in the sources include Montana’s Senate Bill 473 (reported passed by a chamber in March 2025 and awaiting further action), North Carolina’s House Bill 362 (referred to committee), Rhode Island’s HB 5217 (introduced), and Kentucky proposals that would ban SAI among other measures [3] [6]. Minnesota Republicans introduced legislative language with broad bans including SAI but that proposal was characterized as unlikely to pass in its political context [7]. These items indicate a patchwork of introduced measures, with different status and scope [3] [7] [6].
3. Variation in statutory language — from narrow weather-modification bans to sweeping prohibitions
The scope of the laws and proposals differs. Florida’s 2025 law is described as a “blanket prohibition” on weather modification and solar radiation modification, while Montana’s SB 473 (as reported) bans SAI and solar radiation management but expressly permits cloud seeding for water management and seeks to integrate with state environmental code — showing a narrower and more targeted approach [3]. Other bills mix weather modification, “xenobiotic agents,” and expansive criminal language, which critics say could unintentionally affect aviation, agriculture, broadcasting, or scientific research [7] [4].
4. Politics, conspiracy narratives, and motivations behind the wave of bills
Coverage links many of these state efforts to politics and conspiratorial concerns, including claims about “chemtrails.” Tennessee’s debate explicitly included allusions to chemtrails, and some sponsors in other states have invoked federal reports and conspiracy rhetoric to justify bans [1] [6]. International and national press coverage warns that such politically driven or conspiracy-tinged initiatives may mislead the public and could criminalize legitimate scientific research [4] [1].
5. Science and federal posture: research continues despite state bans, and federal actors provide context
Federal and scientific sources emphasize that SAI remains largely theoretical and that the U.S. government is not conducting outdoor SAI field tests; at the same time, federal reports and agencies have examined research and governance options [2]. Experts warn SAI would have complex climate, ozone, and regional effects — which underlies calls for robust governance rather than ad hoc bans [8] [9] [10]. Geoengineering-monitoring organizations and academic coverage show experimental activity and debate internationally, adding nuance to why states are reacting [5].
6. Limits of the available reporting and what’s not found here
The provided sources document Tennessee and Florida as enacted bans and list many introduced bills (Montana, Kentucky, North Carolina, Rhode Island, Minnesota among them), but they do not provide a single authoritative, up-to-date inventory of every state’s final legislative status as of today; available sources do not mention the complete current status for every state nor do they supply full statutory text for each listed bill [3] [2] [7]. For a definitive, up-to-the-minute list, consult state legislatures or a legal-tracking service beyond these articles.
Bottom line: reporting in these sources identifies Tennessee [11] and Florida (June 2025) as states with enacted bans that cover SAI and solar radiation modification, while multiple other states have introduced or advanced bills with varying language and likelihood of passage; those bills are frequently entangled with political and conspiracy-driven rhetoric even as federal scientists emphasize caution and governance [1] [2] [3] [4].