Scientists disprove airplane 'chemtrail' theory

Despite conspiracy theories, white aircraft trails in the sky aren’t harmful chemicals sprayed from planes, according to a new study.

Though some people call them "chemtrails," the white streaks in the sky are actually condensation in the air that’s been heated by a plane’s engine and then frozen by the cold temperature, according to retired airline captain and USA TODAY contributor John Cox.

Some "chemtrail" conspiracy theorists believe the white trails are a cocktail of dangerous chemicals sprayed from planes in a plot to control the population and food supply.

But a group of researchers surveyed 77 atmospheric chemists and geochemists to determine whether any evidence of chemical spraying from planes existed. The survey results, published in Environmental Research Letters, found that 76 of the 77 scientists surveyed said there is no evidence that "chemtrails" exist.

“Our survey found little agreement in the scientific community with claims that the government, the military, airlines and others are colluding in a widespread, nefarious program to poison the planet from the skies,” study co-author Steven Davis, a University of California-Irvine associate professor of earth system science, said in a statement. 

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Proponents of the "chemtrail" theory have tried to support their argument with what they claim are soil and water samples that contain toxic substances from the spray, Davis said in a statement.

According to the survey, the methods some groups recommend for collecting water and soil samples could provide faulty results. People were encouraged to use Mason jars with metal lids to transport samples, a practice the researchers said could tarnish the entire sample, rendering it “useless.”

While many "chemtrail" theorists note that there seems to be an increase in the streaks, researchers point to a correlation with an increase in air traffic, according to Carnegie Institution for Science researcher and study co-author Ken Caldeira.

“Contrails are becoming more abundant as air travel expands,” Caldeira said in a statement. “Also, it is possible that climate change is causing contrails to persist for longer than they used to.”

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While Davis acknowledges that the research likely won't sway die-hard conspiracy theorists, he said it's important "to go on the record with fundamental scientific facts to refute claims that the government is deliberately spreading harmful chemicals from aircraft.”

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