Florida enacts comprehensive weather modification ban

TALLAHASSEE, Fla. —The Florida Legislature passed Senate Bill 56 on July 1, 2025, to protect Floridians from unauthorized chemical exposure and atmospheric manipulation. The bill repeals the state’s ability to issue permits for geoengineering and weather modification, prohibiting the release, injection and dispersal of substances into the atmosphere for the purpose of changing the Earth’s temperature, sunlight intensity, weather or climate. Tennessee passed a similar bill in 2024.

The bill requires publicly owned airports to submit reports to the Florida Department of Transportation on aircraft equipped for geoengineering. The Florida Department of Environmental Protection will receive reports, investigate violations and collect fines, depositing them in the Air Pollution Control Trust Fund. Florida lawmakers stated there is a lack of federal oversight for weather modification; therefore, the state wants to control its own airspace. Supporters of the bill believe there is not enough scientific research to allow these types of activities to occur and that it is important to protect the public from the release of substances, chemicals or devices into the atmosphere.

Private companies such as Stardust Solutions, a U.S.-Israeli startup, focus on solar geoengineering by spraying reflective particles into the stratosphere. This company has already raised $75 million in startup funding and claims it will work in collaboration with governments, respecting rules and regulations that are not yet written. A California-based startup called Make Sunsets releases sulfur dioxide (SO2) into the stratosphere using weather balloons, selling "cooling credits" to private customers. This company has been scrutinized by the U.S. Environmental Protection Agency and received international criticism for operating outside of any regulation.

Geoengineering covers the deliberate manipulation of the Earth's dynamics, atmosphere or outer space. Climate engineering is defined as using human-created scientific processes to counter the effects of climate change through deliberate intervention. Solar radiation modification techniques reflect some of the incoming sunlight back into space to cool the planet, such as through stratospheric aerosol injection or marine cloud brightening.

Professor David Keith of the University of Chicago's department of the geophysical sciences is the world’s leading expert on geoengineering. He said, “Climate engineering technologies may allow humans to protect themselves and the environment in ways that cannot be achieved by emissions cuts alone. Yet these technologies bring environmental risks and pose deep challenges for governance. No one should be confident about embracing or abandoning these methods. My only confident assertion about climate engineering is that open collaborative research today is vital to inform decisions our children must make tomorrow. I’m thrilled to join the University of Chicago with its commitment to open debate and its legacy of tackling society’s greatest tests."

Weather modification experiments began in 1891, when the U.S. government conducted trials in West Texas that included atmospheric explosions using dynamite, kites and balloons to trigger rain, which were largely ineffective. In 1938, Henry Houghton developed a method for fog dissipation around airports.

By 1946, modern cloud seeding had been discovered, which included dropping dry ice pellets into clouds to trigger precipitation. On Oct. 13, 1947, the U.S. military’s Project Cirrus made the first attempt to seed a live hurricane with dry ice. The storm abruptly changed course and hit the Florida-Georgia coast, sparking public backlash. Cloud seeding has been used recently during the 2008 Beijing Summer Olympics and to help with regional water supplies in numerous locations. 

On Dec. 10, 1976, the United Nations adopted a law called the Environmental Modification Convention, that prohibits military or any other hostile use of environmental modification techniques that cause widespread, long-lasting or severe destruction or injury. This law addressed concerns over tactics used in the Vietnam War, including the U.S. military’s Operation Popeye, where silver iodide was used to increase the length and intensity of the monsoon season in hopes of winning the war.

Spraying chemicals and substances into the atmosphere is risky. We do not know how it will affect Earth’s natural chemical and biological systems in the future. These stratospheric aerosol injection, or SAI, chemicals include silver iodide, sulfur dioxide, hydrogen sulfide, carbonyl, calcium carbonate, aluminum oxide and amorphous silica. Computer modeling shows that while SAI could lower global temperatures, it could also damage the ozone layer, disrupt rainfall patterns and cause regional droughts.

Harvard University has said that solar geoengineering is like a “Band-aid” or a “painkiller” that only addresses the symptoms, not the underlying cause of climate change. The university stated that it is controversial and is not a substitute for cutting greenhouse gas emissions or adapting to climate change. Geoengineering does not cure the underlying issues we face after harming the Earth’s land surface, biological systems and altering the chemistry of the Earth’s atmosphere. There is mounting evidence that geoengineering and weather modification could be harmful to human health and the health of our planet.