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

Many years ago I gave a talk at a climate science conference at University College London. I don't remember what the meeting was about, but I remember a lot about that day. There were protesters outside when I arrived, which was not unusual for a climate change rally, which in those days typically attracted both activists and deniers.

In this case, the protesters were peaceful; I ignored them and entered. Around mid-morning they entered the lecture hall and began heckling the speaker. They then took to the stage shouting slogans and waving placards.

These were a breed of protesters I had not encountered before—not activists or climate change deniers, but adherents to a conspiracy theory called chemtrails. In a nutshell, this is the claim that contrails, or contrails, left by high-flying aircraft contain chemical or biological agents deliberately released by attackers to control the weather, poison the population, or achieve some other evil purpose.

This is wrong. Contrails are long, thin ribbons of ice crystals that form when water vapor in engine exhaust freezes in the cold air at a commercial aircraft's cruising altitude. They usually dissipate quickly, but under certain atmospheric conditions they can persist for hours, forming cirrus clouds with contrails. These are what the conspirators call chemtrails.

Like everyone else good conspiracy theoriesthis concept contains a grain of truth. The tracks may look eerily beautiful on a summer evening, but they are quietly causing harm to the environment.

Everyone knows that flying is bad for the climate: aviation fuel combustion accounting for about 2.5 percent of humanity's total greenhouse gas emissions. But contrails and cirrus clouds classified as “aeronautical, non-CO₂ climate impacts” – are probably just as bad, if not worse.

This is from the realm of simple physics. Like greenhouse gases, ice crystals in cirrus clouds trap infrared radiation from the Earth into the atmosphere, creating a warming effect. They also reflect incoming sunlight, which has the opposite effect. But overall they cause warming.

The truth is that we simply don't know the full impact of contrails. Last year, recognizing this gap in our knowledge, NASA asked the National Academies of Sciences, Engineering and Medicine to develop a research strategy to better understand and address the climate impacts of contrails.

Published last month, his report showed that contrails contribute to warming to a degree that may exceed the effects of jet fuel (although there is great uncertainty in the numbers). Fortunately, he has found ways to mitigate its effects, such as changing the fuel composition and engine design or rerouting flights to avoid areas where contrails merge into cirrus clouds.

The report makes no mention of chemtrails, and that's understandable. I suspect that the panel of experts was tempted to debunk this baseless conspiracy theory, but decided not to give it a chance to go public. In any case, the report probably won't make much difference, at least under the current US administration. Donald Trump and his team are anti-science and conspiracy theorist climate deniers. Dealing with contrails is unlikely to be on their to-do list. First, it will require restrictions on aviation and the fossil fuel industry, so don't hold your breath.

Indeed, I suspect that the aviation and fuel industries are quietly happy for the chemtrail fanatics to continue their quixotic delirium, since they provide a welcome distraction from the real problem – the impact of contrails on the climate.

In any case, the report will be put on the shelf and a new one will be ordered – on chemtrails. Trump's Secretary of Health and Human Services, Robert F. Kennedy Jr.reportedly flirted with conspiracy as part of his unscientific “make America healthy againAnd this concept definitely still exists, despite – because of? – complete lack of evidence.

Earlier this year, on a sunny afternoon, I exchanged pleasantries with a neighbor. Nice day, I said. It would be so, he answered, if not for them, and pointed to the sky. It was dotted with contrails. He is also a climate change denier.

That's what's crazy about the chemtrails conspiracy – it's completely counterproductive. Despite their scientific illiteracy, I believe the chemtrail conspirators have something interesting going for them: they are rightly wary of corporate and government power and concerned about the environment and human well-being. However, all their efforts are aimed at sucking the energy out of legitimate protest and directing it towards a pie in the sky.

The meeting at UCL was abandoned due to irreconcilable protests. If the criminals thought they had won, they were wrong. Climate change is a real threat – chemtrails do not exist.