How weather conspiracy theories moved from online fringes to state laws

Florida Attorney General James Uthmeier sent a letter to all public airports in the state Monday to warn them of a new law banning any injection of chemicals to change the climate or weather. “Violators of this law are guilty of third degree felonies and fines as high as $100,000,” Uthmeier wrote.

The letter seemed to endorse a persistent conspiracy theory: that cloud seeding “could have played a role” in causing the floods in Texas that have killed at least 132 people.

The Florida law — and Uthmeier’s letter underscoring it — is the latest example in a surge of right-wing support for conspiracy theories that have spread across social media in recent years. Far-right conspiracy theorists say airplanes are leaving “chemtrails” in the atmosphere that can change the weather, harm human health and even control the minds of the population. They assert that the U.S. government is conducting cloud-seeding experiments that were responsible not only for the recent floods in Texas, but also for Hurricane Helene last year.

None of these conspiracy theories is true. But they are nevertheless taking root in the highest offices of government.

More than a dozen states have introduced or passed legislation barring what Uthmeier called “geoengineering and weather modification activities.” This month, Rep. Marjorie Taylor Greene (R-Ga.) said she would introduce legislation in Congress mirroring the Florida law. “We must end the dangerous and deadly practice of weather modification and geoengineering,” Greene wrote on X.

A few days later, EPA Administrator Lee Zeldin said people who asked about geoengineering had been “vilified by the media and their own government.” The EPA later released a set of webpages explaining that airplane contrails are harmless.

In his letter to airports, Uthmeier noted that “developing reports show that a weather modification company conducted ‘cloud seeding’ operations just days before the deadly flood” in Texas. “I can’t help but notice the possibility that weather modification could have played a role in this tragedy,” the Republican attorney general added.

Discussion around “chemtrails” began in the late 1990s, when conspiracy theorists began propagating the idea that airplanes were spreading toxic chemicals to control the population. According to a study published in 2017, 10 percent of Americans believed the theory is “completely” true while another 20 to 30% believed it is “somewhat” true.

The concept got a huge boost during the COVID-19 pandemic, as misinformation spread like wildfire online.

Holly Jean Buck, a professor of environment and sustainability at the University of Buffalo, said the pandemic helped chemtrail conspiracy theorists to get organized, as they began to ally with groups that were against the coronavirus vaccine. “It gave them access to this anti-vaxxer network,” Buck said. “They were organized in a way that people who were dealing with chemtrails just weren’t organized before.”

At the same time, some climate scientists were increasingly discussing solar geoengineering, the idea of injecting sun-reflecting chemicals into the atmosphere to cool the planet in the face of runaway warming. In 2021, the National Academies of Science released a report on a possible research agenda for that technology.

Scientific discussion of geoengineering galvanized people concerned about chemtrails and cloud-seeding, who saw the ideas as linked. Conspiracy theorists, including prominent figures such as Robert F. Kennedy Jr.’s former running mate, Nicole Shanahan, now claim that solar geoengineering is already happening, and that it’s being funded by the federal government.

Last week, an Oklahoma man was accused of vandalizing a weather station radar, in an attack that the station said may be related to fears of government manipulation of the weather.

Researchers on geoengineering point out that no significant outdoor experiments or research is underway. While some scientists are receiving funding to explore these technologies, none have been deployed at a scale that would change weather patterns or the climate.

“It seems like a normal environmental concern, with a lot of the tone and words that are consistent with how people worry about the environment — except that it’s about something that’s not happening,” said David Keith, a professor of geophysical sciences at the University of Chicago who studies solar geoengineering.

Many of the theories, researchers say, are rooted in some small kernel of truth: Some countries have historically devoted resources and money to weather modification experiments, and there is a push to further research geoengineering. That kernel, though, has been stretched into unrecognizable claims.

The psychology behind these conspiracy theories is twofold, experts say. On the one hand, conspiracy theories help take something as uncertain and variable as the weather and make it feel controllable. “People can think, ‘Oh well this horrible thing happened because some rogue company was seeding the clouds,’” said Dustin Tingley, a professor of public policy at Harvard University and the co-author of the 2017 study.

At the same time, extreme weather events are becoming more intense and frequent because of human-caused climate change. Some long-term deniers of that well-established process have been more likely to blame chemtrails or cloud-seeding than to reconsider the climate-altering effects of fossil fuel emissions. “There’s this desire to shift the blame away from ourselves and the way we live onto someone else,” Tingley said. “And that’s a very common thing.”

As states work to ban geoengineering activities, one question is what comes next. Airplanes — even those flying through Florida — will continue to leave harmless contrails visible in the sky. Floods and hurricanes will keep occurring, despite conspiracy theorists’ ardent belief that they can change that.

“If I’m right about any of this,” Tingley said, “they’re going to put in these bans and nothing is going to happen.”