It's not a theory. They have hundreds of patents and publicly admit they are spraying. The reason they give is the lie. Here is a list of patents. Clickable links here: https://www.geoengineeringwatch.org/links-to-geoengineering-patents/

United States Patent and Trademark Office​
0462795 – July 16, 1891 – Method Of Producing Rain-Fall
1103490 – August 6, 1913 – Rain-Maker
1225521 – September 4, 1915 – Protecting From Poisonous Gas In Warfare
1338343 – April 27, 1920 – Process And Apparatus For The Production of Intense Artificial Clouds, Fogs, or Mists
1619183 – March 1, 1927 – Process of Producing Smoke Clouds From Moving Aircraft
1665267 – April 10, 1928 – Process of Producing Artificial Fogs
1892132 – December 27, 1932 – Atomizing Attachment For Airplane Engine Exhausts
1928963 – October 3, 1933 – Electrical System And Method
1957075 – May 1, 1934 – Airplane Spray Equipment
2097581 – November 2, 1937 – Electric Stream Generator – Referenced in 3990987
2409201 – October 15, 1946 – Smoke Producing Mixture
2476171 – July 18, 1945 – Smoke Screen Generator
2480967 – September 6, 1949 – Aerial Discharge Device
2550324 – April 24, 1951 – Process For Controlling Weather
2582678 – June 15, 1952 – Material Disseminating Apparatus For Airplanes
2614083 – October 14, 1952 – Metal Chloride Screening Smoke Mixture
2633455 – March 31, 1953 – Smoke Generator
2688069 – August 31, 1954 – Steam Generator – Referenced in 3990987
2721495 – October 25, 1955 – Method And Apparatus For Detecting Minute Crystal Forming Particles Suspended in a Gaseous Atmosphere
2730402 – January 10, 1956 – Controllable Dispersal Device
2801322 – July 30, 1957 – Decomposition Chamber for Monopropellant Fuel – Referenced in 3990987
2881335 – April 7, 1959 – Generation of Electrical Fields
2908442 – October 13, 1959 – Method For Dispersing Natural Atmospheric Fogs And Clouds
2986360 – May 30, 1962 – Aerial Insecticide Dusting Device
2963975 – December 13, 1960 – Cloud Seeding Carbon Dioxide Bullet
3126155 – March 24, 1964 – Silver Iodide Cloud Seeding Generator
3127107 – March 31, 1964 – Generation of Ice-Nucleating Crystals
3131131 – April 28, 1964 – Electrostatic Mixing in Microbial Conversions
3174150 – March 16, 1965 – Self-Focusing Antenna System
3234357 – February 8, 1966 – Electrically Heated Smoke Producing Device
3274035 – September 20, 1966 – Metallic Composition For Production of Hydroscopic Smoke
3300721 – January 24, 1967 – Means For Communication Through a Layer of Ionized Gases
3313487 – April 11, 1967 – Cloud Seeding Apparatus
3338476 – August 29, 1967 – Heating Device For Use With Aerosol Containers
3410489 – November 12, 1968 – Automatically Adjustable Airfoil Spray System With Pump
3429507 – February 25, 1969 – Rainmaker
3432208 – November 7, 1967 – Fluidized Particle Dispenser
3441214 – April 29, 1969 – Method And Apparatus For Seeding Clouds
3445844 – May 20, 1969 – Trapped Electromagnetic Radiation Communications System
3456880 – July 22, 1969 – Method Of Producing Precipitation From The Atmosphere
3518670 June 30, 1970 – Artificial Ion Cloud
3534906 – October 20, 1970 – Control of Atmospheric Particles
3545677 – December 8, 1970 – Method of Cloud Seeding
3564253 – February 16, 1971 – System And Method For Irradiation Of Planet Surface Areas
3587966 – June 28, 1971 – Freezing Nucleation
3601312 – August 24, 1971 – Methods of Increasing The Likelihood oF Precipitation By The Artificial Introduction Of Sea Water Vapor Into The Atmosphere Winward Of An Air Lift Region
3608810 – September 28, 1971 – Methods of Treating Atmospheric Conditions
3608820– September 20, 1971 – Treatment of Atmospheric Conditions by Intermittent Dispensing of Materials Therein
3613992 – October 19, 1971 – Weather Modification Method
3630950 – December 28, 1971 – Combustible Compositions For Generating Aerosols, Particularly Suitable For Cloud Modification And Weather Control And Aerosolization Process
USRE29142 – May 22, 1973 – Combustible compositions for generating aerosols, particularly suitable for cloud modification and weather control and aerosolization process
3659785 – December 8, 1971 – Weather Modification Utilizing Microencapsulated Material
3666176 – March 3, 1972 – Solar Temperature Inversion Device
3677840 – July 18, 1972 – Pyrotechnics Comprising Oxide of Silver For Weather Modification Use
3722183 – March 27, 1973 – Device For Clearing Impurities From The Atmosphere
3769107 – October 30, 1973 – Pyrotechnic Composition For Generating Lead Based Smoke
3784099 – January 8, 1974 – Air Pollution Control Method
3785557 – January 15, 1974 – Cloud Seeding System
3795626 – March 5, 1974 – Weather Modification Process
3808595 – April 30, 1974 – Chaff Dispensing System
3813875 – June 4, 1974 – Rocket Having Barium Release System to Create Ion Clouds In The Upper Atmosphere