Complex Numbers

Pros and Contrails

In a sane world, this PopSci article would put an end to one of the stupidest conspiracy "theories" immediately.

    Why airplanes leave white streaks in the sky  
Contrails are a problem, but not how you might think

Of course, in a sane world, the "theory" would never have gotten traction in the first place.

If you’ve ever looked up at a mostly blue sky and seen straight white lines criss-crossing the horizon, or watched a plane puff out a plume as it passed above, you may have wondered, “what causes that?”

Yeah, back when I was a kid. This was before the internet, so I used the version of Wikipedia we had back then: I asked my dad, who launched into a long-winded explanation of what he called vapor trails.

I think that was his way of keeping me from asking too many questions: answer so thoroughly that I'd get bored and stop asking questions.

And no, they’re also definitely not “chemtrails.”

I'd like to think that, even without the influence of my father's scientific mind, I still wouldn't have bought into that idiocy. But I can never be sure.

What they are, instead, is frozen water vapor crystallized on soot particles, both of which are standard byproducts of a jet’s combustion engine.

Well, there you go: the answer.

And though conspiracy theories about airplanes distributing mind control chemicals aren’t correct, contrails are having a negative planetary effect.

Because of course they are. Nothing we do is allowed to actually be good for the environment.

Atmospheric conditions have to be just right to enable the jet vapor to crystallize: moist enough that the water doesn’t evaporate, and cool enough that it freezes.

But as everyone knows, thanks to the internet, nothing that's described as "moist" can ever be cool.

A growing body of scientific research, including studies conducted by both Barrett and Stettler, indicate that contrails cumulatively have a warming effect, contributing to human-caused climate change.

These studies are important, because the leading hypothesis that I'd heard was that, being basically cirrus clouds, they'd have the effect of reflecting some sunlight, reducing the "heat in" side of the climate warming equation.

Perhaps they do, but other things about them overshadow (pun intended) that.

Since contrails, like other clouds, are bright white and insulating, they reflect light and heat, and also trap it. On a sunny day, a contrail does two things simultaneously. It “acts like a blanket,” preventing heat radiating from Earth’s surface from escaping to space, says Barrett–this is the warming effect. Simultaneously, it also reflects sunlight from space away from Earth’s surface, in a cooling effect. Unfortunately, even when the sun is shining, generally the blanket effect outweighs the reflector effect, says Barrett.

At least according to this guy.

Anyway, the article goes into what can be done about them, and, surprisingly, the answer isn't "just stop flying" or "stop using plastic straws." In other words, this is one contributor to climate change that can be mitigated fairly easily, and it's not even about us doing penance for how sinful humans are (just corporations).

And yet, some of us are just going to blithely keep on believing that they're mind-control chemicals.