Dirty vapour trail over London

A few days ago, I was out and about snapping, as is my wont, and I saw something rather unfamiliar in the sky over London, a dirty-looking vapour trail.

Vapour trails usually look white, as the older vapour trail that makes an X with this new one is. Something about the way vapour trails are usually lit makes them look white, against a blue sky. Mechanical clouds, you might say. And what could possibly be wrong with that? Vapour trails are just nice, clean steam.

But that one looks a whole lot dirtier, doesn’t it? And there’s the remnants of another, across the X, horizontally.

This was snapped just before it got dark, and I presume that has something to do with it. For some reason, this particular vapour trail was not lit. High clouds blocking the sun from it, but not blocking the sun from lighting us down on the ground? Or the older vapour trail, the one that’s white? I don’t know.

What I do know is that if vapour trails always looked this dark and dirty, there would surely have been a lot more talk about restricting air travel even than there is. Air travel would long ago have become more expensive.

Now, you could say that clouds are often this dark too, presumably for similar reasons. But clouds look natural. This vapour trail looks like mechanised evil spewing into the sky. It looks, in other words, just what the environmentalists have finally persuaded a lot of people that it is, despite usual appearances to the contrary.

Originally posted at Brian Micklethwait’s Old Blog

One thought on “Dirty vapour trail over London”

  1. The third comment, posted two years and more after the original posting, is of particular interest:


    You’re right – I love looking up at those big white X’s you get in the sky when two vapour trails cross – if they were all black and mean like that one the romance evaporates and your left with the stark reality. Makes you think…

    Thanks for the article.

    Kate. Lovetolead.

    Posted by kate on 21 February 2007



    Thank you for the kind words.

    Although, you can agree with how nasty this particular vapour trail looks without necessarily accepting that nastiness is the “stark reality” of it.

    I repeat, dark clouds are just as dark, but nobody worries about them. It could surely be that vapour trails are no more harmful than dark (presumably because rather thick and hence badly lit) clouds are.

    If vapour trails are harmful, that’s a distinct argument, I would say.

    Posted by Brian Micklethwait on 21 February 2007


    Hello there

    I flew from Prague to Stockholm on Tuesday afternoon and photographed about 8 of these from different planes. Without exception they were all black.

    In my 12 years of traveling I have never seen this.

    Have you been able to find an explanation? Happy to share the photos.



    Posted by Matt Harris on 04 September 2009

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