Ban geoingenierie
Executive summary
Calls to ban solar geoengineering (often called SRM or “geoengineering”) are rising: more than a dozen U.S. states introduced bans in early 2025 and advocacy groups and some countries pressed for a global non‑use agreement at U.N. fora [1] [2] [3]. Supporters of bans point to unknown environmental and health risks and existing international precautionary measures; opponents warn that a ban could foreclose research needed to understand risks and tradeoffs [4] [5] [1].
1. What proponents of a ban say — prevent a Pandora’s box
Organisations like Heinrich Böll Stiftung, OceanCare and legal advocates argue that solar geoengineering risks “far‑reaching unintended consequences,” could divert resources from emissions cuts, and should be halted via bans or “non‑use” agreements to avoid opening a Pandora’s box of harmful technologies [6] [3] [4]. These actors point to scientific uncertainty about impacts on weather, droughts, hurricanes and ozone as grounds for immediate restriction and explicitly call for bans on outdoor experiments or deployment [6] [4].
2. Domestic laws and momentum in U.S. states
State legislatures have moved quickly: reporting shows over 16 states had introduced bills to ban solar geoengineering in the first three months of 2025, with at least 22 state proposals tracked later in 2025 and Tennessee already passing a ban in 2024; Florida and other states have enacted or advanced laws prohibiting weather‑modification activities that encompass SRM [1] [2] [7]. Proposals vary — some are broad weather‑modification bans, others target SRM specifically — and several bills explicitly ban practices like stratospheric aerosol injection, cloud seeding or releasing atmospheric particulates [8] [7].
3. International posture — moratorium, contested governance
At the U.N. and multilateral level, countries remain divided. Some Global South groups and the Convention on Biological Diversity’s de facto moratorium have pushed restrictive stances, while other states and panels have resisted an outright research ban, keeping SRM legal under most national laws but subject to a patchwork of precautionary decisions and calls for governance [5] [4]. Reporting from UNEA shows no consensus to ban or strictly regulate SRM globally, leaving “the status quo” and calls both for moratoria and for structured research [5].
4. Why critics of bans object — foreclosing knowledge and options
Experts who urge caution about a ban argue that prohibiting outdoor experiments or constraining research could prevent society from learning key tradeoffs such as public‑health effects, climate‑justice impacts, and how SRM would interact with rising temperatures — information some scientists say is needed to weigh whether any limited use could reduce net harms [1] [9]. Commentators in policy and scientific circles warn governance frameworks may be a better path than blanket prohibitions so responsible research can proceed under oversight [9] [5].
5. Conflation with conspiracy claims and political dynamics
State measures and political debates often blur legitimate scientific research with long‑debunked “chemtrails” conspiracies; local coverage of bills in Kentucky and Florida notes lawmakers sometimes invoke public fear of “chemtrails,” while scientists stress contrails are frozen water and not evidence of clandestine geoengineering [10] [11]. Political actors and advocacy groups with differing agendas — anti‑geoengineering campaigners, skeptical legislators, and conspiracy proponents — are all shaping the public narrative [10] [12].
6. Practical policy differences — moratoria, research bans, or deployment bans
Not all “ban” proposals are the same. Some call for a global non‑use agreement or ban on outdoor field experiments; others prohibit any weather modification or single out SRM while permitting narrowly defined weather modification like cloud seeding. The EPA and legal advocates document this variation and note there is currently no unified international framework to govern outdoor SRM research and deployment [7] [4].
7. What reporting does not say (limits of current sources)
Available sources do not provide a comprehensive tally of which specific statutory texts survive legislative process in each state nor an authoritative cost‑benefit of banning versus regulated research beyond cited studies and advocacy claims; they do not establish that large‑scale SRM deployment is currently happening [7] [11]. Sources note only one private actor reported as having done an SAI/MCB activity in the U.S. as of mid‑2025, and that SRM is not occurring via routine commercial aircraft contrails [7].
8. Bottom line for policymakers and the public
Policymakers face a choice between precautionary bans aimed at preventing unknown harms and governance approaches that allow tightly controlled research to reveal risks and tradeoffs; international consensus is absent and state‑level politics are accelerating measures that, depending on wording, could either close off experimentation or focus mainly on conspiratorial fears [4] [5] [10]. Readers should scrutinize whether a proposed “ban” targets legitimate scientific research, conflates contrails/chemtrail rhetoric with SRM, or genuinely aims to forestall real deployment risks [11] [8].