Prior to the Environmental Modification Convention signed in Geneva in 1977, the United States used weather warfare in the Vietnam War. Under the auspices of the Air Weather Service, the United States' Operation Popeye used cloud seeding over the Ho Chi Minh trail, increasing rainfall by an estimated thirty percent during 1967 and 1968.
It was hoped that the increased rainfall would reduce the rate of infiltration down the trail.
With much less success, the United States also dropped salt on the airbase during the siege of Khe Sanh in an attempt to reduce the fog that hindered air operations.
A research paper produced for the United States Air Force written in 1996 speculates about the future use of nanotechnology to produce "artificial weather", clouds of microscopic computer particles all communicating with each other to form an intelligent fog that could be used for various purposes. "Artificial weather technologies do not currently exist. But as they are developed, the importance of their potential applications rises rapidly."
Weather modification technologies are described in an unclassified academic paper written by air force officer-cadet students as "a force multiplier with tremendous power that could be exploited across the full spectrum of war-fighting environments."
The technology to control weather does exist, and you can bet that the words describing this technology are as foggy and dense as the clouds they create. Nevertheless, the evidence is there. The dates shown are but a few of the more recent additions to the ever-growing, ever-polished machine of man-made control of mother nature.