Chemtrails are not real. But thanks to the "echo chambers" of social media, more and more Americans are starting to believe the conspiracy.
In a new study, Harvard scientists have found that about 10 percent of Americans believe chemtrails are "completely" true, and about 20 to 30 percent believe they are "somewhat" true, according to data from the 2016 Cooperative Congressional Election Study (CCES).
In other words, around 120 million Americans subscribe to the idea that tens of thousands of commercial airplanes are secretly spraying toxic chemicals across the US every day.
It gets crazier.
Depending on who you speak to, the goal of the chemtrails conspiracy ranges from large-scale weather modification to mass population mind control.
Conspiracy theorists argue that contrails, or the white streaks you see in the sky behind airplanes, are evidence of chemtrails. Yet, scientists maintain that contrails are simply water vapor and they have been a byproduct of aviation ever since the first jet engine. Scientists, investigative journalists and the Environmental Protection Agency all agree there is no evidence that contrails contain any toxic chemical or biological agents.
Nevertheless, the Harvard study suggests social media is creating a breeding ground for this bogus conspiracy.
Already, researchers have noticed the conspiracy is becoming more popular. Back in 2013, only 5 percent of US respondents subscribed to the chemtrails conspiracy theory, according to Per Publica Policy Polling. That means that in just three years the number of people who believe in chemtrails has doubled.
The study was conducted because Harvard scientists are worried that chemtrail conspiracy theorists are hijacking rational conversations about geoengineering. Geoengineering describes the manipulation of environmental processes that affect the earth's climate, and many scientists believe the field holds key answers to combatting the effects of climate change.
But online, it is conspiracy theorists - and not scientists - who are driving this conversation.
Using a social media analysis platform, researchers analysed every English-language mention of geoengineering on social media from May 2008 to May 2017.
The findings reveal that 60 percent of social media discourse on geoengineering was focused on the topic of chemtrails, with 90 percent of that discussion occurring on Twitter. Meanwhile, neutral reporting about actual science accounted for just 3 percent of the discussion.
"These conspiracy numbers are frighteningly high, despite everything we know about online echo chambers [and] bots," said economist and co-author Gernot Wagner.
Wagner and his co-author theorize that this trend is occurring because of the relative anonymity afforded by Twitter and other social media platforms. According to the authors, the best way to combat this "broad online community" of conspiracy theorists is to expand the online scientific community.
But this is easier said than done.
With a growing number of people subscribing to the chemtrails conspiracy, clearly scientists cannot afford to keep dismissing the topic as "fake news." On the other hand, the authors also acknowledge that addressing the issue often does nothing but spread it further.
Much like the anti-vax movement, chemtrail conspirators do not respond well to scientific evidence that disproves their theory. Instead, they are masters at picking and choosing the proof they need to support their views.
"Regardless of possible unintended consequences, fighting tweets with peer-reviewed analyses does not work," the authors write.
"Much more promising are attempts to engage at the same level, speaking to chemtrail conspirators directly using social media platforms."
Getting the conversation back on track will not be easy, but it is important. After all, online behavior has direct consequences for climate science communication and policy.
The study was published in Palgrave Communications.