Airplane contrails are actually toxic chemical sprays. The chemtrail theory became one of the world's most widespread conspiracies — because anyone can look up and "see the evidence."
On a clear day, look up and you will see white lines trailing behind aircraft. Normal contrails -- condensation trails -- form when water vapor in jet exhaust freezes at high altitude. They typically dissipate within minutes.
But sometimes contrails linger for hours, slowly spreading into thin, hazy sheets. The chemtrail conspiracy theory begins with this observation. Those persistent white lines, chemtrail believers say, are not normal contrails. They are chemicals or biological agents deliberately sprayed by governments or shadowy organizations.
Note: The chemtrail conspiracy theory has been scientifically debunked. The following discusses it as a social phenomenon.
The chemtrail theory emerged in the late 1990s and spread rapidly through the internet in the 2000s. The specific claims vary among proponents, but the most common include the following.
Mass dispersal of toxic substances to reduce global population. Secret weather modification programs, or geoengineering. Aerial spraying of psychoactive drugs to pacify the public. Deliberate soil contamination to enable corporate control of agriculture.
Some proponents claim the substances being sprayed contain metals such as aluminum, barium, and strontium, citing soil and water sample tests as evidence.
Atmospheric scientists can fully explain why some contrails persist for hours. The duration of a contrail depends on the temperature and humidity at the altitude where it forms. In high-humidity conditions, contrails can persist and spread for hours. This phenomenon, known as "persistent contrails," has been documented in meteorology textbooks since the 1940s.
In 2016, the Carnegie Institution for Science surveyed 77 atmospheric scientists and geochemists worldwide. Seventy-six of them, 98.7 percent, reported finding no evidence of a secret spraying program. The supposedly anomalous soil samples cited by chemtrail believers were shown to be explainable through natural geological processes.
The chemtrail theory derives its power from the visual immediacy of its "evidence." Look up and you can see the white lines. Unlike most conspiracy theories, it requires no specialized knowledge, no investigation, no research. The sky is the evidence, every single day.
The history of actual government atmospheric experiments also feeds suspicion. During the Vietnam War, Operation Popeye saw the U.S. military conduct cloud-seeding operations to extend the monsoon season. Cloud seeding technology continues to be used around the world today.
The logic flows easily: the government has sprayed things from the sky before, so they must be doing it now. This reasoning deftly blurs the line between established fact and unfounded speculation.
In recent years, research into Solar Radiation Management, or SRM, has advanced as a potential climate change mitigation strategy. The idea involves dispersing aerosols into the stratosphere to reflect sunlight and slow global warming. Chemtrail proponents interpret this research as an admission that chemtrails are real.
However, SRM remains in the research phase and has not been implemented at scale. More importantly, the scientific study of geoengineering and the claim that ordinary contrails are toxic chemical sprays are fundamentally different propositions.
Tomorrow, look up at the sky. You will see white lines. They are water vapor. Science says so with near-total certainty. But millions of people around the world see something else entirely.
