Chemtrails Over Kansas City

A jet flies over the Overland Park, Kansas area near Kansas City and leave behind a trail of chemicals.

Wikipedia: The chemtrail conspiracy theory posits the erroneous[1] belief that long-lasting condensation trails are "chemtrails" consisting of chemical or biological agents left in the sky by high-flying aircraft, sprayed for nefarious purposes undisclosed to the general public.[2] Believers in this conspiracy theory say that while normal contrails dissipate relatively quickly, contrails that linger must contain additional substances.[3][4] Those who subscribe to the theory speculate that the purpose of the chemical release may be solar radiation management,[3] weather modification, psychological manipulation, human population control, biological or chemical warfare, or testing of biological or chemical agents on a population, and that the trails are causing respiratory illnesses and other health problems.[2][5]

The claim has been dismissed by the scientific community. There is no evidence that purported chemtrails differ from normal water-based contrails routinely left by high-flying aircraft under certain atmospheric conditions.[6] Although proponents have tried to prove that chemical spraying occurs, their analyses have been flawed or based on misconceptions.[7][8] Because of the persistence of the conspiracy theory and questions about government involvement, scientists and government agencies around the world have repeatedly explained that the supposed chemtrails are in fact normal contrails.[3][9][10]

The term chemtrail is a portmanteau of the words chemical and trail, just as contrail is a portmanteau of condensation and trail.

Chemtrail conspiracy theories began to circulate after the United States Air Force (USAF) published a 1996 report about weather modification.[10] Following the report, in the late 1990s the USAF was accused of "spraying the U.S. population with mysterious substances" from aircraft "generating unusual contrail patterns."[6][12] The theories were posted on Internet forums by people including Richard Finke and William Thomas, and were among many conspiracy theories popularized by late-night radio host Art Bell, starting in 1999.[13][8] As the chemtrail conspiracy theory spread, federal officials were flooded with angry calls and letters.[10][3]

A multi-agency response attempting to dispel the rumors was published in 2000 by the Environmental Protection Agency (EPA), the Federal Aviation Administration (FAA), the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA).[14][15] Many chemtrail believers interpreted agency fact sheets as further evidence of the existence of a government cover-up.[3] The EPA refreshed its posting in 2015.[16]

In the early 2000s the USAF released an undated fact sheet that stated the conspiracy theories were a hoax fueled in part by citations to a 1996 strategy paper drafted within their Air University titled Weather as a Force Multiplier: Owning the Weather in 2025.[17][18] The paper was presented in response to a military directive to outline a future strategic weather modification system for the purpose of maintaining the United States' military dominance in the year 2025, and identified as "fictional representations of future situations/scenarios."[18] The USAF further clarified in 2005 that the paper "does not reflect current military policy, practice, or capability," and that it is "not conducting any weather modification experiments or programs and has no plans to do so in the future."[6][19] Additionally, the USAF states that the "'Chemtrail' hoax has been investigated and refuted by many established and accredited universities, scientific organizations, and major media publications."[6]

The conspiracy theories are seldom covered by the mainstream media, and when they are, they are usually cast as an example of anti-government paranoia.[4] For example, in 2013, when it was made public that the CIA, NASA, and NOAA intended to provide funds to the National Academy of Sciences to conduct research into methods to counteract global warming with geoengineering, an article in the International Business Times anticipated that "the idea of any government agency looking at ways to control, or manipulate, the weather will be met with scrutiny and fears of a malign conspiracies" [sic], and mentioned chemtrail conspiracy theories as an example.