The US government has been accused of using chemtrails and HAARP for weather warfare by some conspiracy theorists. Chemtrails are said to be chemical or biological agents sprayed from aircraft trails that persist in the atmosphere for hours and can spread out into large areas. The conspiracy theory claims that these trials are used for weather modification or mind control.

HAARP (High-frequency Active Auroral Research Program) is a research program that was funded by the US Air Force, Navy, and University of Alaska Fairbanks. It was designed to study the ionosphere and its effects on radio communication and navigation systems¹. However, some conspiracy theorists believe that HAARP is capable of controlling weather patterns and causing natural disasters.