How pie-in-the-sky conspiracies distract from climate dangers

Years back, I attended a climate science conference at University College London. While I can’t recall the specifics of the conference, I vividly remember the scene outside. Activists were demonstrating—a familiar sight at climate events, which often draw both proponents and skeptics of climate science.

This time, the protesters were non-violent, and I decided to ignore them as I entered. Midway through the session, they burst into the auditorium and began heckling the speaker. Soon after, they stormed the stage, chanting slogans and brandishing signs.

These demonstrators represented a type of protester new to me—not traditional climate activists or deniers, but believers in a conspiracy theory regarding chemtrails. In brief, this theory claims that the condensation trails, or contrails, left behind by high-altitude flights contain harmful substances, released by nefarious individuals to manipulate weather patterns, poison populations, or fulfill other malicious intentions.

This claim is false. Contrails are merely long, narrow strands of ice crystals that form when water vapor in aircraft exhaust freezes at cruising altitudes. They typically vanish quickly, but under certain conditions, they can linger for extended periods, forming contrail cirrus clouds, which the conspiracy theorists term chemtrails.

Like many conspiracy theories, this one contains a grain of truth. While contrails can create stunning visuals in the evening sky, they are also detrimental to the environment.

It’s common knowledge that flying negatively impacts the climate: aviation fuel combustion is responsible for about 2.5 percent of global greenhouse gas emissions. Yet, the effects of contrails and contrail cirrus clouds, classified as “aviation non-CO₂ climate effects,” may be as damaging, if not worse.

This is rooted in fundamental physics. Similar to greenhouse gases, the ice crystals within cirrus clouds trap infrared radiation as it escapes from the Earth, leading to a warming effect. They also reflect incoming sunlight, providing a cooling factor. However, overall, they contribute to warming.

The reality is that we have yet to fully understand the implications of contrails. Last year, NASA acknowledged this knowledge gap and tasked the US National Academies of Sciences, Engineering, and Medicine with formulating a research framework to better comprehend and address the climate repercussions of contrails.

Published last month, the report indicated that contrails might contribute to warming to a degree that could surpass the effects of aviation fuel (though substantial uncertainties surround these estimates). Fortunately, it also proposed measures to lessen these impacts, like modifying fuel blends, enhancing engine technology, or rerouting flights to steer clear of areas where contrails might coalesce into cirrus clouds.

The report doesn’t mention chemtrails, which is understandable. I suspect the expert panel may have been inclined to dismiss this unfounded conspiracy but opted against giving it undue attention. Regardless, the report is unlikely to influence policy much, particularly with the current US administration. Donald Trump and his associates are known for their anti-science stances and climate skepticism. Addressing contrails is unlikely to be a priority for them since it would entail imposing restrictions on the aviation and fossil fuel sectors—so don’t expect quick changes.

In fact, I suspect both the aviation and fossil fuel industries prefer to see chemtrail advocates pursue their misguided efforts, as these activities divert attention from the real issue: the climate implications of contrails.

It’s likely that the report will gather dust, only to be replaced with another study—this time on chemtrails. Trump’s health and human services secretary, Robert F. Kennedy Jr, has apparently shown interest in this conspiracy as part of his unscientific initiative to “Make America Healthy Again.” The theory continues to circulate, thriving—perhaps because of—the complete absence of credible evidence.

<p Earlier this year, I had a friendly conversation with a neighbor on a bright afternoon. I commented on the lovely weather, to which he responded that it would be perfect if it weren’t for the aircraft overhead casting contrails. He, too, is a climate change skeptic.

The most frustrating aspect of the chemtrail conspiracy is its complete ineffectiveness. Despite their lack of scientific understanding, I believe those who subscribe to this theory hold valid concerns: they are rightly cautious of governmental and corporate authority and care for the health of the planet and its inhabitants. Unfortunately, their actions do little more than siphon energy away from genuine advocacy and misdirect it towards a baseless pursuit.

The UCL conference was ultimately canceled due to the relentless protests. If the protesters thought they had triumphed, they were mistaken. Climate change presents a significant threat—chemtrails are purely fictional.