Home » contrails » Why do some planes leave long trails, but others don’t?

Why do some planes leave long trails, but others don’t?

Some planes in the sky leave trails that persist and spread, and other planes, in the same sky, leave short-lived trails, or no trails at all.

These trails are actually called contrails, short for “condensation trails”.  They are not smoke from the engines, they are formed when the water in jet engine exhaust (and there’s quite a lot of it, like car exhaust on a cold day) mixes with wet cold air and condenses and freezes into ice crystals.  Contrails are actually a type of cirrus cloud.  When the air is wet and cold enough the trails can stay around for a long time, and sometimes spread out.

This difference between trails that fade away, and trails that spread, is often used as evidence of the “chemtrail” theory, which states that the longer lasting trails (or some of them) are being deliberately manipulated for some reason.  So you see helpful images like this.

But this is wrong. Contrails can fade away, and contrails can persist and spread. It depends on the air they are formed in.

Now there are two main reasons why some planes leave trails and some nearby planes do not.  The less common reason is that different planes have different engines.  Some engines will leave a contrail in the air where another engine will not.  Here, for example, are an Airbus A340 (maiden flight: 1991) on the left, leaving contrails, and a Boeing 707 (maiden flight: 1957) not leaving contrails. Both are flying at 33,000 feet (part of a German test to study contrail formation), but the exhaust of the newer engines of the A340 is at a lower temperature, and so makes contrails in a wider range of conditions*.

You can also get a similar effect with engines at different power settings, especially if it affects the exhaust temperature. This can occasionally be seen with high altitude refueling, when the plane being refueled cuts the throttle to near idle in order to separate from the tanker.

Contrails in a refueling situation turn on/off

But here’s the main reason why you see trails on some planes but not on others, and I’ll emphasize it, because although it’s simple, it’s also easy to miss.

The planes are at different altitudes.

Yes, it’s really that simple.  The reason that one plane makes contrails or makes contrails that persist, and the other plane does not, is that they are in different regions of the air.   For simplicity, let’s refer to these regions of air as wet air and dry air, although the differences are a bit more complex.

When the plane is in wet air, it makes a contrail.  In dry air, it does not.

Surely, you might object, they would have to be miles apart?  Well, no, and that brings me to another point I fear I must emphasize:

Wet and dry air can exist within a few feet of each other.

Consider, for example, clouds:

Inside the cloud it’s wet.  Outside it’s dry.  What’s the difference between inside and outside?  It’s a few feet.

Look at the bottom of those clouds, see them extend off into the distance.  They form a layer at a specific altitude. Above that altitude there are clouds.  Below it there are no clouds.  The difference between clouds and no clouds is just a few feet.

Now those are low altitude cumulus clouds.  Let’s look at high altitude clouds.

Again they are in a flat layer.  The difference between being in the layer and not in the layer is just a few feet.

This layering of the air into wet and dry layers is not limited to clouds.  Seemingly clear air also contains exactly the same kind of variation in layers.  This was very neatly illustrated by the recent launch of the Solar Dynamics Observatory.  As it ascended it did not leave a contrail, until it hit a layer of wet air, when it left a contrail that lasted quite a while, and then it went into dry air again, and no more contrail

So, if a plane were flying in that middle region then it would probably leave a persisting contrail.  If it were above or below it then it would not.

But, you may cry, the planes are at the same altitude.   Now you might even disagree with a “few feet”, and say the planes were too close for them to be in different layers.  I’d respond with:

You can’t tell how high a plane is

And you certainly can’t tell if one plane is at the same altitude as another.   These planes fly at 30,000 to 40,000 feet.   Let’s see what the visual difference is at around that altitude:

I took one image of a jet nominally at 35,000 feet. Then scaled it for 34,000 (102.9%) and 32,000 feet (109.4%). I think you’ll agree they all look pretty much the same. Especially as this is more zoomed in than you’d see with the naked eye, which would be more like:



If the planes are flying lower, then it’s still similar. If the top plane was flying at 20,000 feet, then the bottom would be at 18,285 feet, still nearly 2,000 feet apart, and looking pretty much the same to the naked eye.

And that is with the same model of plane, directly overhead, and right next to each other. A situation that almost never occurs. If the planes are different, or separated, or at an angle to you, then it is IMPOSSIBLE for you to tell the relative altitudes when they are high in the sky.  Just look at this:

Or from the ground, with the planes at 30,000 feet.


They look about the same height, right?  In fact, if they were not overlapping, you’d think the JAL plane was lower, as it seems bigger, hence closer.  But actually, the JAL plane (a B777) is at least 1000 feet above the DHL plane (an A300).

And look at some planes on the ground, where we know they are all the same distance from the camera. The differences in size are very significant:

So, a simple question gets a simple answer:

The planes leave different trails because the planes are at different altitudes.

See Also:
https://contrailscience.com/broken-contrails/ – Why contrails are often broken and start and stop abruptly.

Debunked: High Bypass Turbofans do not make Contrails [actually they make more] – A more detailed look at why modern engines make contrails in a wider range of conditions.

*(Edited 3/15/2015): when I wrote this article in 2010 I’d said that the newer more efficient engines produced “more water”, and while it’s true that the cleaner the combustion the more water is produced, the difference is negligible for the two engine types discussed. The key difference is the exhaust gas temperature, as explained in the more recent  Metabunk article

376 thoughts on “Why do some planes leave long trails, but others don’t?

  1. captfitch says:

    This is an excellent addition! To the first point regarding the different engines- you need to get a screen shot of an aircraft with an apu running in flight- sometimes the apu creates a contrail when the engines aren’t and vise-versa. Same aircraft, same altitude- different engines, different contrails. Of course, most chemtrail believers don’t know anything about an apu.

  2. Like this:

    There are a few “chemtrail” pages that show a mysterious third or fifth trails

  3. Virga aka Pegasus says:

    Hi Uncinus, long time no see.

    I have a little addition to your information.
    Sometimes an extra trail is caused by the dumping of wastewater via vents on the underside of the fuselage.

    This video refers to this as a chemtrail:

    When looking at the Tu-134 we se that the water dump point is at the same location as the origin trail in the video.

    Here is a picture shot of 2 airliners including the corresponding radar image. I often use it to explain the impossibility of guessing an aircraft’s altitude.

    Here is a nice example of the very local variation of the atmosphere, an Air China 744 creates an aerodynamic contrail on departure from Schiphol:

  4. Virga aka Pegasus says:

    I mostly say: Different engines of different age with different powersettings on different locations create different contrails.

  5. Suntour says:

    Wow, I knew nothing about the APU, I have read about the heated drain masts that grey water is released from, but haven’t paid attention to the APU. That helps to explain some of the “two engines, three contrails” type questions.

  6. I mostly say: Different engines of different age with different powersettings on different locations create different contrails.

    Yeah, but I’m pretty sure that “different locations” accounts for most of it. You’ve only got to look at how an individual semi-persistent contrail varies as it moves across the sky. It’s a patchy sky up there.

  7. Wiki seems to suggest the APU is not generally used in flight:


    Though this will vary with plane. Some APUs auto shut-off at altitude. I think APU trails are pretty rare. I’ve never seen one myself, and there are very few photos of APU trails. Some of the supposed photos might be mast drains, or even a third tail mounted engine not visible from the ground.

    Some more informed discussion here:


  8. Virga aka Pegasus says:

    We rarely use the APU in flight, the most common reason to keep the APU running during takeoff is to have more power on the engines, although this is different for each type of aircraft.

    The aircraft I fly on -The A320- has different priorities:
    On ground the APU supplies bleed air and electricity.
    On takeoff the APU provides bleed air, preventing a power reduction on the engines.
    In flight it backs up both electrical and bleed air system

    We can use the APU bleed for 2 packs up to 15.000 feet, for 1 pack up to 20.000 feet.
    We can use the APU for power up to 39.000 feet.

  9. Murdag says:

    I didn’t know you were also a rocket scientist. I am not a rocket scientist, I am only a layman, but would like to point out that rocket exhaust from an Atlas V rocket ( or whatever types this may be) is not the same as engine exhaust from a commercial airliner engine. They are made up of different types of gasses and therefore cannot be used to compare anything in this argument. Do you have scientific measurements of that particular airmass that is highlighted as “Wet”, as actually being of a higher humidity reading than the other two dry airmasses? What if rocket exhaust due to its composition exhibits different effects as it passes throught different layers of humidity. Do you have observations of other rocket launches? Is rocketry another of your hobbies? Rocket fuel has additives like oxydisers. Maybe that explains this white looking trail that we see. Rocket launching can be very technical. Sometimes different types of fuels and mixtures are used at different times during a lauch to achieve higher buring rates to gain velocity. Maybe that is what we are seeing there. Sometimes they vent of stuff during the course of a rocket launch. Do rockets go straight up as your arrow indicates. Did this rocket go straight up? Where is your proof that this rocket went straingt up? What is the operating temperature of rocket exhaust during the various stages of assent? What are the differences in temperature and humidy that enable you to lable the photo as a wet or dry zone. Do you have the met data from this location for the different layers of atmoshpere? You have left me with way more question than you have answered. Can you please help me understand?

  10. Murdag says:

    Your photo of the fifth contrail above could actually also be from another jet that is flying at a higher altitude than the jet we see. We cannot see this second jet because it is higher and smaller than this big jet and is being obscured by the big jet. Is this not possible? This is a bad photo. Without a good photo this is a bad argument.

  11. Well, I’m no rocket scientist, but Dean Pesnell is, and he said, regarding this image:


    A contrail from the launch appeared only in the region of Earth’s atmosphere where conditions were right for cloud formation. “There weren’t any clouds there, but we provided the very fine particles so that a contrail cloud appeared,” said Pesnell.

    Which is what this post is about – that there are some regions of air that are different from other regions of air. Contrails form in those regions.

    The rocket was an Atlas V, which burns Kerosene + Oxygen for the first stage, then Hydrogen + Oxygen for the next stage. Both produce lots of water. I’m not sure which stage was operating when the contrail formed (I suspect the kerosene), but the point is about the composition of the air, not the rocket exhaust – either one would work.

    I label the regions as wet and dry based on where the contrail shows up, the description from the rocket scientist.

    Since the rocket was ging into orbit it would not be going exactly straight up all the way, but not too far off. It certainly started straight up.

  12. Your photo of the fifth contrail above could actually also be from another jet that is flying at a higher altitude than the jet we see. We cannot see this second jet because it is higher and smaller than this big jet and is being obscured by the big jet. Is this not possible? This is a bad photo. Without a good photo this is a bad argument.

    Maybe. It does not change the argument that some planes operate the APU in flight, and this creates an additional contrail.

  13. Murdag says:

    As you state “The different between being in the layer and not in the layer is just a few feet” and I am to understand that this could then effect the formation of contrails. Using this argument, and looking at the second photo from the top, are those two planes at exactly the same altitude? Perhaps the plane on the right is flying in a different layer an that is why we a re not seeing the formation of a contrail. Do you have the actual measured flight altitudes of these two aircraft? Is one aircraft ahead of the other? Without a line of reference or actual flight altitude data, this is a bad photo should not be used in this aurgument.

  14. The photo shows two planes that were part of a study into the formation of contrails. They were deliberately flown together at the same altitude. One made contrails, one did not. Photo notes:


    Shown below is a photo taken from the research aircraft Falcon of the German Aerospace Center (Deutsches Zentrum fh r Luft- und Raumfahrt (DLR) at about flight level 33,300 feet of an Airbus A340 with contrails (left) and a Boeing 707 without contrails (right). This illustrates a scientific effort to evaluate the effects of different engine characteristics on contrail formation.

    The point here is that different engines produce different contrails. This is established science which nobody disagrees with (although not everyone is aware of it). The photo is simply a demonstration.

  15. Murdag says:

    When it rains the rain is wet and it is directly outside the cloud. This effect of the wet being on the outside of the cloud can continue all the way to the ground. Due to different atmospheric condidtions sometimes this effect only goes a short way before it evaporates again. Do you have humidity measurements of that particular cloud that it is indeed dry where the arrow is pointing. Without evidence, this photo is a bad example and should not be used in this argument.

  16. My, you certainly have demanding standards of photos. I expect you must dismiss every single supposed “chemtrail” photo that is out there?

    It is a photo of a cloud. A cumulus cloud. They are all pretty much the same.

    The clouds are in a layer. Below the base of the clouds there are no clouds forming. Obviously there is something different in the air above and below this level. The precise figures of humidity are not important.

    Above the level clouds form (I call this “wet”)

    Below it they do not (I call this “dry”)

    That’s all that is being claimed here, and that’s exactly what the photo shows.

  17. JazzRoc says:


    When it rains the rain is wet and it is directly outside the cloud.
    When trails form they are DRY. They form in apparently “clean air” (it isn’t, it is WET with water vapor – but the water vapor is DRY at -40 degrees C).

    This effect of the wet being on the outside of the cloud can continue all the way to the ground.
    This “effect of the wet being on the outside” is known as water vapor.

    Due to different atmospheric condidtions sometimes this effect only goes a short way before it evaporates again.
    You mean, because of the variable ambient humidity rain can sometimes evaporate away. This happens with contrails too: whenever the humidity falls to less than 70%, then the contrail sublimes directly to water vapor because it can’t normally enter its liquid phase at that atmospheric pressure (0.2 Atm).
    If the ambient air is more humid than 70% then the chances are the contrail will PERSIST. You have to remember that such conditions exist in about 17% of the stratosphere at any time.

    Do you have humidity measurements of that particular cloud that it is indeed dry where the arrow is pointing?
    As Uncinus has pointed out, humidity measurements aren’t necessary to prove the point. That you feel you need them directly demonstrates to everyone that you don’t yet understand what you are talking about.

    Without evidence, this photo is a bad example and should not be used in this argument.
    The photo is DIRECT EVIDENCE as it stands. (Unless you claim it to be false. Please don’t waste time in such a manner).

    It is quite apparent to anyone qualified in these matters that you know very little, as you admit.

    What puzzles us all is why you think you know enough to be “challenging”. Before those of us who are qualified were indeed qualified, we at least knew enough to know not to do so – at least until we knew a modicum of the subject.

  18. Murdag says:

    Thanks for the quick response to my questions. You have very imformative site here.

  19. Murdag says:


    I came here to learn about “contrail science”. After reading the very first article and looking at the pictures I had questions, so I asked them. I learned to question things by reading your posts.

  20. JazzRoc says:

    Murdag, fair enough. 🙂

  21. JazzRoc says:

    Getting back to your interesting pics above, Uncinus, I especially liked the near-vertical rocket trail picked out as it passed through a succession of wet layers.

    I suggest its a succession because of its very raggedness. That raggedness is a physical readout of the lateral motions in the layers; they are sliding sideways to each other, for what you see is the result of what happened.

    There was a similar and possibly larger step in the exhaust trail of the “Challenger” Shuttle takeoff, showing the high crosswind shear that had jolted out the temporarily-sealed SRB joint, causing a flame to play upon and cut through the rear SRB strut a few seconds later…

  22. High altitude rocket trails always end up distorted a lot by the wind shear.

    Multiple images:


    This one shows a nice progression from clean to ragged trail:


  23. Archeopterix says:

    Hi Uncinus,

    This is a fascinating website you have here. Very interesting and enlightening. I’m a 30 year old in North Carolina who’s been watching the skies for a few years now since I first heard of ‘chemtrails’. I personally tend towards the belief that they exist (and rather prefer I didn’t believe it at all).

    I tend to think of myself as a generally pretty fellow that is pretty scientific. So I have some questions for you.

    I’m not sure if you’ve explained these before as I just ran into your site.

    Number one, I wanted to ask, what’s up with the planes flying curved paths? I thought most planes flew ‘by wire’, guided by radar beams? Radar beams do not take curved paths as I remember from school. I studied lasers at the college level for a while and I can tell you that energy on the shorter end of the frequency certainly does not take a curved path. So doubtful radar beams do. What that means then is that the pilot is deliberately veering to the side. Now, that’s not to say that it’s because he’s been ordered to spread a deadly chemical but I’d like to know what makes a pilot deviate like that. Admittedly it could be anything and I’m no aviation buff; however I believe you pointed out that you’re a pilot yourself.

    And my second question is: If ‘persistent contrails’ are nothing more than tiny ice particles, actually a man made cirrus cloud, then why is it that you see under some of them long streamers of ‘dribbly’ stuff coming down from the spaced every so many yards apart? (It looks like a few inches at arm’s length; I assume it’s actually several tens of feet or even greater given the height the planes are at.) It does not look like ice crystals or water vapor. It looks more like a trail of some sort of fine aerosol powder which is being dispersed in a stream. I haven’t seen any of the bottles of old borax based roach powder that you squirt out of the little red tube in a while but that’s precisely what it looks like to me.

    Again, even though I tend to personally believe ‘something’s up’ (no pun intended, I assure you) I’m not completely immune to common sense, either. If there’s a rational explanation I would dearly love to hear it. I’m not interested in inflaming anyone’s beliefs or stepping on toes or picking fights. I’m not going to tell anyone “Well it’s obvious you’re all asleep’ and I’m not going to tell anyone ‘you’re crazy, take off your tinfoil hats and grow up’ either. I just simply would like to know some answers to these questions and I’d say starting out by asking an actual aviator is as good a place as any.

    Thanks for helping out.

    (PS..since I get this a lot in these forums, yes, I know my name is misspelled, and that it’s actually archaeopteryx. It’s done that way for ‘creative’ reasons. )

  24. captfitch says:


    I’m happy to address your first question as I take every chance to explain this to chemtrail believers. I am also a pilot, flying jets at all altitudes all over the country.

    The first thing you must know when it comes to chemtrail theory and aircraft navigation is THERE IS NO SUCH THING AS NORMAL JET ROUTES!! With a few exceptions we can fly wherever or however we want. If I wanted to go up over New York City and fly circles at 30000 feet for two hours I could ask for that and i imagine I would be allowed to. If I wanted to go spell my name over Kansas I could certainly do that. Not that I would since it costs my compamy money to go waste fuel. Jets primarily navigate by a mixed use of GPS and ground based sources. We also usually use a predetermined matrix of published routes and procedures (arrivals and departures as well as approaches) but ther is nothing that says we must stay on those routes and ATC on a daily basis takes us off routes, gives us shortcuts, reroutes us etc.

    Don’t let anyone tell you that “those are not usual routes”! There is no such thing. And as far as curving routes goes- yes, we aim to fly as straight a route as possible but sometimes you have to have bends in the route for a number of reasons. We are not guided by radar beams- we are tracked by them (not much longer though).

  25. DC3 says:


  26. archeopterix says:

    Hi Uncinus, and thanks for explaining airplane routes. As I said I’m not an aviator and so I don’t know that much about aviation as it’s not a topic I ever really endeavored to learn much about. Much appreciated.

  27. captfitch says:

    Actually that was me who explained the routes, although I sure uncinus could have told you the same.

  28. Faithinscience says:


    “Grandma” didn’t teach you well at all. Where did “grandma” learn about atmospheric science/aviation enough to pass the knowledge down to you? LOL! I love how you people who have NEVER studied this subject are so confident about your “knowledge” and so completely oblivious to your ignorance. There is a VERY good reason why EVERYONE who has ever (actually) studied these subjects believes as I do, because we are right. It’s obvious that you aren’t even interested in the truth here, you badger those who are educated but cheerfully accept the trash you read online about the subject, from those who have never learned the subjects from those in a position to teach the subjects. You “believe” you understand the truth because early on, you made a decision…you decided to accept anything that says these trails are “chemtrails” and reject anything that says they are normal persistent contrails. Suggesting that we are the ones lying is ridiculous.

  29. hyundisonata says:

    do not think your bosses would like you wasting their fuel lol. ok you make a lot of good points but you still have given me no explanation why the skies are now different from the seventies or eighties, we had jets then that dumped a lot more pollution into the air than they do now, the atmosphere is still the same . Yet now the sky is painted white from only a few certain unmarked aircraft. Yes contrails can last a while but when you are watching from the ground this systematic griding of the sky then watch the trail fall like a veil towards the ground and start to sting your skin and eyes you are left with no option but to believe the conspiracy. If it is not chem. Trails then it means the airlines are causing very nasty pollution that carries the same stigma as chem. Trails.

  30. The older engines actually made fewer contrails as they were less efficient. The more efficiently an engine burns fuel, the more water it produces.

    How can you tell these planes are unmarked if you don’t have a photo of one?

    Do you have a photo of the the “griding”?

    Why not do a little science. Let’s say the plane is at 30,000 feet (about six miles). Now if something were being sprayed up there, how long do you think it would take to reach the ground? (think how long would it take for mist to travel six miles) How long does it take in your observations?

    Do another experiment. You have noticed that when you watch this activity, then your eyes seem to sting. One wonders why millions of people are not simultaneously complaining of stinging eyes? Is it just you? Try this: go outside and pretend a plane is spraying. Stare up at the sky for as long as you normally do. See if your eyes start to sting from the light and exposure to the elements. Compare that to your past experience.

  31. Also, check this site:


    Click on the planes heading from your area. You see a lot of planes coming from Europe. Match that with what you see.

  32. hyundisonata says:

    Six to eight hours before it got stingy and that was long after they finished the grid and the trails had become widespread. You keep referring to high altitude spraying; I have noticed two levels that alleged chem. Trails are formed. The lowest being similar in height to commercial aircraft such as easy jet approaching Edinburgh airport, now I am not a pilot so I do not know what the norm approach height is but no doubt as you are a pilot you will know. I noticed you side stepped the pollution aircraft distribute lol. then we also have to take into account the role contrails play in global warming, radiative forcing springs to mind , looks like your in a no win loose situation lol. Now as I see it the argument is not about the existence of contrails. It is the additives we believe that are added to the contrail thus we now have chem. Trail. Then this chem. Trail is sprayed across an area in a manner that is outside the norm for that area defiantly leaves a big question mark that no real given answer is forthcoming. The use of weather conditions as an answer would suffice if it was normal for aircraft behavioral patterns of this nature in the said area. But when you have an influx of aircraft into an area on top of your normal traffic and are the only ones leaving contrails especially in a well recognized pattern then questions should be asked. As for the engine reply sorry but that holds no water lol. a large percent of any fuel is water and a good chunk is passed out via the exhaust so old or new it will at some time create a contrail as the water is passed out into the atmosphear. this still leaves me without a viable explanation in the difference of skies though the jet engine era .

  33. How far are you from Edinburgh?

    Remember that trans-atlantic jets can be 2-5 times the size of local jets. So could be 2-5 times as high. Got any photos to illustrate what you claim?

    A percentage of the fuel is not water. It’s hydrogen. It burns with oxygen to produce water. A gallon of fuel produces more than a gallon of water. Modern engines produce more than old engine, as they burn more efficiently.

    However the primary reasons for trails is the atmospheric conditions at that altitude. This can vary in a few hundred feet, and one the biggest cause of trails vs. no trails is going to be altitude. You can’t tell the difference between 28,000 feet and 30,000 feet from the ground.

    I think the difference you see is attributable to various possible things:

    1) There’s a lot more jet traffic now than there was 20 years ago.
    2) Jet engines are bigger and more efficient, producing more and larger contrails
    3) You have become suspicious of contrails because of the “chemtrail” theory, so you have been looking for them, so you notice them more. (Note that most people never notice them, just like you used not to notice them).

    Also it’s possible a localized thing – you live in a remote location. Possibly international air traffic has changed course somewhat with GPS or a change to a nearby VOR. Possibly the RAF changed where it conducts test operations.

    Or maybe there’s a huge secret conspiracy costing trillions of pounds, involving millions of people, revising all the world science books, silencing all the scientists, all to experimentally alter the worlds atmosphere?

    Weigh the evidence. “I can’t think of a reason” is not a good reason to jump all the way to conspiracy.

  34. Anonymous says:

    Why are the Germans studying contrails?? Could it be they are putting poisonus gases in the mixture and we are all being poisioned as the Illuminati claims they will do??!!

  35. No, that’s not it. They study contrails because contrails can affect the climate by altering the amount of cirrus cloud cover.

  36. Raymond says:

    I like this video of a concord breaking the sound barrier, it looks to be making a nice big contrail as well. I don’t think the concord had room on board for chemical tanks.


  37. Peter says:

    This is just a mistification. surely the US Government, Northropp Grumman, Lockeed Martin, Raytheon, FACC etc. payed you very good.

  38. Artyom says:

    Under what evidence do you have that anyone here, that doesn’t agree with you, is on the payroll ‘being PAID’ by Defense Contractors. Just because you don’t understand that the atmosphere is layered and dynamic means this whole website is untrustworthy? Since those at youtube know better, why don’t you come back here with facts to prove anything written here wrong. You think I am on the payroll too? I don’t know how they’d be giving a Russian citizen money for commenting here. Also do enlighten us what you mean by mistification. Some people worked very hard educating themselves so you may want to study harder before attempting to insult people through paranoid claims that they are “paid shills” misinforming you.

  39. Coaltrain says:

    I like to keep things scientific. I like the firmament of empirical evidence on which to place my flag of faith. Some of you have explained what contrails are to death here, and that is actually awesome for a guy like me. That being said, how can anyone here disprove that though contrails are water vapor, some could be chemtrails that inherit the same properties? I’ve seen the unusually geometrical “gridding” of contrails in the skies of southern Cal once or twice. Also, in regards to the Chemtrail theory: Why, if they do exist, does their intent have to be about affecting a population? Why does it all have to be so nefarious? Could it not be some kind of atmospheric manipulation (I’m sure thats not the right term), if that’s even a thing?

  40. You’re asking if it could be disproven that some trails are not contrails, but instead are other trails that simply look and behave exactly the same as contrails?

    Or course you can’t disprove that.

    But the real question is why you would suspect such a thing. Can you expain why you would NOT expect to see “gridding” occasionally in SoCal, given the grid nature of the high level overhead traffic (note particularly the flights between Hawaii and various points to the east of here).

  41. Coaltrain says:

    Just stirring the pot, for the most part, in saying that the only thing that’s certain, especially in this day, is that nothing is, no matter how educated a persons vocabulary. It’s human nature to be suspicious; to look for psychological intent behind things, especially those things that seem peculiar. Conspiracy theories are at the extreme of this condition. Since you’ve asked, Uncinus, I might suspect some kind of atmospheric manipulation in this region as a countermeasure to the prolonged dry conditions that result in costly wildfires, or the pollution that can linger and pose a hazard to the public. I don’t know, I’m just spitballing here.

  42. “Nothing being certain” is the foundation of science. But then so are reasonably grounded hypotheses.

    WHY do you suspect “some kind of atmospheric manipulation in this region”? Is there any evidence that it it is occurring, or do you just think it’s the type of thing someone might do.

  43. Coaltrain says:

    I have zero evidence to support my suggestions, sir, and I’ve no education relative to this topic. I’m just curious. Seeing things and wondering what could be- the imagination often leans towards the sexier options. There’re a lot of people and a large economy in Cali. A governing body might do all they could to control harmful, intrusive factors in such a region, including the weather, if they had the means at their disposal. No?

  44. Sure, but they could do ANYTHING. Why this in particular?

    You pick a theory, that if it were true would almost certainly have a vast amount of evidence to support it, and yet there is none. In this case absence of evidence is actually evidence of absence.

    It’s like if someone said there were unicorns living in the desert. Sure, it’s quite possible. But why even suggest it if there’s no evidence.

    And why would they be secret about it? Local municipalities have been cloud seeding for decades, so why would the “chemtrail” project need to be secret.

    I’m all for speculation. But it helps if the speculation is not entirely at odds with observed reality.

  45. Coaltrain says:

    I guess I’m using the weather theory because it’s the least threatening to use as an example, and therefore the least likely to trigger a defensive or dismissive response. I’m sure there is evidence out there to support the theory or scarier ones, but I’m not going to go pouring over them because I’m just not that curious. I was just curious enough to pose a question on this site, which was very enlightening!

    OK, why is anything kept secret? Again, you’re asking my opinion? ‘Cause it’s morally reprehensible or too scary for a population to handle? Potential blowback has been the reason for secrets throughout history.

    I’ve received no grants to conduct studies on chemtrails or their effects, sir. I bow to your superior knowledge of this. You asked me to speculate, so I did. Suggestion without evidence; the formulation of ideas outside the senses is called imagination, which is no stranger to science either. If my ideas don’t challenge you- you’re a smart guy, why don’t you imagine why such a thing might exist, and stay a state secret?

    I posed a question: With everything said in this chat, could chemtrails be? You answered it the best you could. Thanks. The rest of this is has turned into a metaphorical Contrail thats starting to obfuscate the initial question.

  46. I can imagine millions of theories. There is nothing wrong with imagining things.

    It seems that all you are asking is “is it possible that people in a position of power have abused that power at the expense of the general population”. Now the answer to that is “yes”. So let’s just take that as read, and see if we can figure out ways of find out HOW they have abused that power.

    I think you’ll find that the vast majority of people who believe in the “chemtrail” theory also believe there is a lot of evidence that supports that theory, and that’s why they are so interested in it. You claim that you don’t know of any evidence, but you thought it might be something “they” would do.

    It’s quite technically feasible. There have been lots of papers and discussions on how to do such a thing (although none involve secret spraying). But there’s simply no evidence that anyone has every tried altering the weather with persisting spreading contrail. And if they do it in the future, then there is every indication that it will be quite open.

  47. Coaltrain says:

    Classy. Cheers.

  48. JazzRoc says:

    Written by Coaltrain on June 23, 2010. “Classy. Cheers.”

    I’ll say.

  49. Vladimir says:

    I don’t know if these chemtrails/contrails are poisonous or not. I can only see that every day they cover HUGE part of the sky. So no more clear skies, no more proper sun light. The sun light is really important when it comes to physical/mental health.

    You know what pineal gland is. Here is some info about it.

    “The pineal gland is incredibly important. It influences sex organs and bodily development. It inhibits the excess production of hormones by other endocrine glands and can retard the growth of both malignant and benign tumours. The pineal secretes melatonin, seratonin, pinealin, lysine vasopressin, norepinephrine, acetylcholine, and histamine. These substances have many, many functions – including helping to regulate blood sugar levels, influencing adrenal hormones, protecting the pancreas from oxidative damage, and helping to control fluid retention. Scientists have not yet discovered all there is to know about the pineal.”

    “If the pineal gland does not have adequate sunlight, it will try to make do with whatever it can get. Artificial, indoor lighting provides only a small portion of the wavelengths of light that the sun does. The missing wavelengths make a difference to our health.”

    Unfiltered sunlight is really important to how we function.

    I live in London and the skies are always covered. The only time when there were no trails was when the volcano in Iceland erupted. I could see the difference in my mood. And believe me this change didn’t come from the fact that I knew about contrails,chemtrails etc. It was so natural.

    So I was thinking about how sunlight is connected to the way we perceive life.
    I was thinking about alternative energy sources.
    I was thinking about the people of the power elite and how they perceive things, their values, their goal in life etc…
    I was also thinking how Internet gives us the possibility to share experience and teach each other so quickly.
    I was also thinking what the power elite people were thinking about that.
    I was thinking about the media and how it influences us.
    I was thinking about how people are stuck to their TVs and have lost touch with themselves and nature.
    I was thinking how easy is to control these people…..

  50. That’s an interesting theory. Unfortunately it does not really stand up to scrutiny. There are much bigger variations in the amount of sunlight that people get than contrail cover, and none of them seem to make a difference to health. If your theory were correct then there would be a vast difference in mental and physical health between the UK (sunny about 30% of the time) and Arizona (sunny about 80% of the time).

    I’d agree people need to get out more, exercise and watch less TV. But I really don’t think contrails have anything to do with it.

  51. Anonymous says:

    Vladimir, do you have any evidence that ANYONE has been affected by the loss of light from the persistent contrails?! Do you have ANY facts and figures about this subject at all, or did you just “find” this information on the internet and accept it as fact?

  52. JazzRoc says:

    Vladimir, you only have to Google, or especially WIKI “SMOG” to discover that LONDON’s problem with noxious and low-illumination atmospheres is 300 years old.
    Some elementary geographical history will demonstrate to you that skies need no external agency in order to become overcast anywhere on the planet.
    Three hundred years ago the same “governing elites” were still broking their power as they do today. If they had wished to dominate and control (and surely they must have), they must have had other equally effective means to do that, which had no visibility.
    So why would they suddenly choose a high visibility way of doing something which they had zero visibility and tried-and-tested ways which worked already?
    What are they spraying if air samplers everywhere find only trace amounts of ambient metallic particulates in their filters?
    Where are they spraying from if the wings and engines are physically incapable of handling corrosive, expensive, and volatile liquid metal compounds?
    Why doesn’t the EXHAUST from these aircraft show the COLORS of ionized metals? (Barium would glow GREEN, and Aluminum would glow a WHITISH PINK. These colors are NOT subtle…
    And so on. These questions about the PRACTICALITIES of what would be required are too numerous to fully cover, and a negative outcome from ANY SINGLE QUESTION is sufficient to dismiss the “chemtrail” hypothesis as unviable. All outcomes are negative…
    The “chemtrail” hypothesis fails all tests and it represents a socially-divisive MEME.
    A positive spin on it is that it powerfully demonstrates a nadir of technical inadequacy and misunderstanding in western society which would be dangerous to ignore and leave uncorrected. It’s a link in a chain of disinformation which seems hell-bent on social oblivion.
    Who was it that said “90% of everything is CRAP”? – Theodore Sturgeon
    “Perhaps the other 10% is Science.” – JazzRoc

  53. Anonymous says:

    Two Alex Jones articles that demonstrate how he can’t except a contradictory viewpoint even when it is published by a major newspaper.

  54. Steve says:

    Great website JazzRoc, thanks for the new info about the colors of ionized Barium and Aluminum. I have to post a piece of one off your comments from the comment section of the Alex Jones article. I could’t of agreed with you more.
    “Chemtrailers” are TERRORISTS, sometimes unwitting, sometimes not.
    It’s about time we all dispelled this product of ignorance and fear

  55. Chromatose says:

    “And believe me this change didn’t come from the fact that I knew about contrails,chemtrails etc. It was so natural.”

    Vladimir….. this sentence alone should tell you your perception was indeed altered by your “knowledge”. This really illustrates why the scientific method is so important. Our observations are unavoidably and invariably filtered through our experiences, our feelings, our beliefs… Hard data is really the only thing that can prove your statement, and you have none.

    One thing I really can’t stand about proponents of the chemtrail theory (yes it is just a theory) is that they act like the burden of proof is on the contrail side (for lack of a better term), and then they completely dismiss the mountain of data that proves they are simply contrails.

    Chemtrail conspiracy theorists (completely ignoring all factual evidence) basically say “You can’t prove me wrong so I must be right”. No, thats not how it works at all.

  56. Artyom says:

    Here’s another Alex Jone’s posted story that will get chemtrailers all rialed up, but this time the people are particularly attacking one man.


    Too bad Hepa filter tests will never tell you what came from a contrail. Too bad that his particulate tests also shows no traces. So what, he is covering up as they say. Lunacy… So it only gets deeper and deeper with these people.

  57. XtyMiller says:

    Your site wants to discredit that chemtrails exist, but I live in Shasta County and see them, and know the effects that they’re having on the health of people here. I network with others that have done soil and water samples on their property, and they aren’t false. I also take pictures of the trails that start in the morning on “spray days”, by afternoon they spread out and turn into a blanket covering, with what looks similar to an overcast sky. And the video done in this area “What in the world are they spraying” may have the KSLA news piece in it, but that was just a video I believe Michael found and added to his video trailer. Earlier this year geoengineers said they were going to use geoengineering create a reflective mirror consisting of particulate matter made up of aluminum, barium, and other ingredients to deflect the suns rays. I think they’ve been experimenting with it for years, but because of all the attention it’s getting they had to pretend they’re only now going to start doing it. I notice on spray days there are way more planes flying. And these do not fly in the normal flight path, like the regular scheduled flights do, this is not a big city, and we don’t have a lot of air traffic here, but on spray days these planes are like ants in the sky, one after another, all over the sky. This is no way not normal air traffic. I’ve called the airport myself and questioned it. They could not explain the extra planes. And what are your credentials? You never cite any of your claims. You just blog.

  58. Artyom says:

    Do you realize the weather dictates whether or not you see contrails and for how long? Do you realize the atmosphere is open system.. Open to space even… Do you realize that it is fluid like water that hit has jet streams, vortexes, cyclonic activities… Do you realize it is layered and the difference between a humid pocket of air and dry air can be a matter of a few meters? Do you understand that assuming that an illness related to something seen in the upper stratosphere is a MAJOR Assumption that is probably the least likely cause of an illness. Bacteria, viruses, and environmental pollution can be major causes, yet all variables are off the table because you make correlation without cause and effect. If contrails are common, I can link them to increase in cancer. Does it mean contrails increase cancer? NO. KSLA is nonsense, discredited 3 years ago as a numbers error.

    Have you played the game of telephone. Because last I read from the actual documents from the forum on geoengineering was they planned to use SULFUR which has reflective properties in the UPPER atmosphere. These are plans and there is no evidence they even tried it. The Barium, Aluminum aren’t even apart of the discussion. Do you know Barium is a commonly present compound on earth? Do you know the oil industry uses this? Do you realize Aluminum is one of the MOST common compounds on earth and it can be mobilized on earth by acid rain(which creates reactions with the soil). Do you understand all these processes to make an assumption that these common materials are put in aviation fuel intentionally that would damage the engines leaving particulates in the exhaust on a global scale? Wouldn’t something involving millions of people everyday lead to the largest chance in history of a conspiracy for a LEAK. Yet no one since 1999 has given any proof other than look up and video contrails to prove their existance. Taking HEPA filters and rain water samples don’t prove what’s in a contrail and NEVER will. Ask any scientist about it and you’ll give them a chuckle. However, finding high concentrations of pollutants is no laughing matter as it is a health risk. Constantly pointing to contrails will never lower the risk until you find the real polluting source.

    So tell me what is a normal flight path. How many pilots do you talk with? Do you know more than one plane flies in the air and when they cross paths, it forms an X… WOW conspiracy…. When they bank, change altitude… OMG not a normal flight path? Do you know holding patterns exist so they can wait to land. They must be targetting a specific house with all these strange patterns, right? Not to mention, all that grid laying would still be a waste trying to hit a village below. Do you know the viewing angle from earth to 30,000 ft up can give equate to long distances and still a particulate such as an “aerosol” can last for days to years in the atmosphere. They find volcanic dust from previous volcanoes years after their eruption, so what makes you think contrails are falling? It is literally a cloud. The sky is not falling.

    Do you understand the atmosphere enough to know super saturated air? Do you understand sublimation? Do you understand anything about the atmosphere? I already know that answer because if you knew the atmosphere and tried to understand it, you wouldn’t be writing what you are now. Instead you likely sit on conspiracy sites and someone pointed it to you and said THAT DOESN’T LOOK RIGHT! They are spraying…. and never paying attention to it, you went to the internet and saw everywhere on youtube and google. Yet no one taught you the atmosphere. Again everything from illnesses to just 1 step in scientific method, making an observation… is the only efforts made by the chemtrail community. Their “Tests” of hepa filters and rain water are rarely posted and sources of tests and who tested them are also rarely published. Add the fact that testing these things will never tell you what’s in a contrail…. EVER!!! So it is intentional fear mongering. You called the air controller, Uncinus could communicate with you now and show you through flight tracker every trail created and give you a flight number if you take photos and give location, time and date. You can do it yourself. Don’t make the mistake of authoritive speaking.

    Contrails have been studied and documented from WWII to now. Everything is explained with contemporary science. The site doesn’t make claims, chemtrailers do… They claim they’re spraying. Contrails are the condensation of engine exhaust, the freezing takes time that’s why there is a gap between engine and trail. How about where are your credentials… You only site your photographs and other peoples 1st hand accounts that are the same as yours. Most of which are assumptive, baseless, and only claims. You won’t find a meteorologist, pilot, atmospheric scientist, and anyone who understands the atmosphere that will agree with this madness.

    The site doesn’t try to discredit anything. It is a re-iteration of contrail facts. Here’s a challenge, you discredit anything here and you will win a cookie.

    There are pilots that comment here that actually fly over the region you live. You live in one busy air corridor. Here is a video of a FedEx planes avoiding a storm, being placed in holding patterns and flying in non straight lines. FAA Radar track Memphis Airport Then an artistic impression with music using FAA flight path information. You can see the United States by just tracking flight paths because there are so many flights at a given time. The two dark spots East of California are military restricted air space, likely where they train Red Flag and have live fire practice and research facilities. FAA Flight Paths Here is a global view and you can see the most claims coming out of US and Western Europe make sense. Also what is interesting in this video is they show the visual of day and night and you can see activity in each part of the world increase and decrease as the people wake up in each region. World Flight Paths

  59. TheFactsMatter says:

    XtyMiller wrote: “Earlier this year geoengineers said they were going to use geoengineering create a reflective mirror consisting of particulate matter made up of aluminum, barium, and other ingredients to deflect the suns rays.”

    THIS is the problem with you people…You CLAIM that “they” said “they” “were going to use a mirror…” But, in reality (where I live, and you do not) it’s a PROPOSAL. There are MANY proposals written for MANY problems we as humans create, but that doesn’t mean they have been implemented! You just ASSUME way too much here. I love how you people believe everything written about this subject from the other “chemtrail believers” (not allowed to use the word “chemtard” here) as “fact”, but can’t even TRY to “believe” the ACTUAL facts simply because you don’t want to “believe” them. Confirmation bias, at it’s finest!

    Sorry, there is absolutely ZERO evidence that anyone is “spraying” anything that results in the long white, long lasting, trails I see over my house….which look exactly like the trails referred to as “chemtrails” by the uneducated. They are persistent contrails, until proven otherwise. And the”proof” I keep seeing is nothing more than proof of the ignorance of those who present it…and those who accept it!

  60. SR1419 says:

    XtY wrote: “You never cite any of your claims.”

    That is simply untrue. An honest review of the material on this site shows Uncinus provides source material for all of his “claim” regarding the nature and science of contrails.

    If you find anything on this site that is untrue- please point it out….

  61. XtyMiller, I don’t have any credentials, but I do try to provide references for everything I say. If you can find some claim I made that I don’t back up, then please point it out.

    And, quid pro quo, if you have a network of people who have done tests, then why don’t you collate those tests, and put them on a web. It seems a little odd that the only time we see these tests is when someone waves them around in a YouTube video. Why not put them on a web page? Or email them to me and I’ll put them up here.

    You have to be careful of contamination though, and the test results need to included the method of collection, and the measures taken to avoid contamination. Like in WITWATS, they tout Aluminum tests on water collected by a schoolgirl in a mason jar. Did she use a lid when transporting it? Lids of mason jars frequently made from aluminum.

    Did she handle a soda can before handling the sample? Was there aluminum siding near the sample site? Any Reynolds Wrap around? Then there’s snow samples collected in ski areas, and skis are made from aluminum. There are all kinds of things to be careful of.

  62. Mike says:

    Back to the “mysterious” 5th contrail from the B747 at the top of the page.

    I’m pretty sure it’s not the APU – the APU exhaust is the hole in the tailcone & it doesn’t line up with that, plus it is visible forward of the port horizontal stabiliser.

    I was wondering if this might be from the outflow valves, aircon or even a toilet wasbasin drain mast?

    It doesn’t look like it’s from the outflow valves – if they are the 2 rectangular marks under the aft service door and opposite – it seems to start too close to them and doesn’t clearly line up with eitehr. AFAIK (never worked on 74’s) the Aircon packs are in the wing roots, and off hand I’d expect a wider train from them if 2-4 were operating.

    Which leaves a drain mast – any 747 mech’s out there who can comment on the position of any drain sump and it’s associated mast?

    Drains (with or without masts) I’m familiar with on 737, 146 and other smaller a/c for water and/or oil are heated to stop them freezing. The are not continually dumping – only when their associated sump is full, or someone is disposing of water – some hand basins dump direct to atmosphere…or used to.

    All speculation on my part tho.

  63. patthecat says:

    Thank you Uncinus for clarifying so many questions that have bothered me for a while…since noticing the airplane grid across the skies for the last 5 years. You make a good case in the con/chem trail debate to show that most observable phenomena are persistent condensation trails.

    However, IMHO I think you should acknowledge a few important points.

    1. As you have stated the contrails become cirrus clouds, and as many have observed the high volume of air trafic results in a cirrus haze that reflects solar radiation and insulates below. Here in Cardiff, UK the clear days often turn out very hazy.
    So effectively we have second-hand geoengineering as a result of air trafic, would you not agree?

    2. Most of our governments have admitted spraying us at some point…infact right now in California to combat LBAM. So now that contrails are so common and easily explained scientifically, if a secret spraying operation was in effect it would have the ideal smokescreen…who would notice are few more lines in the sky that looks like a matrix?

    3. Many people make it sound as if it’s just water vapour that comes out the jet engine and the contrails are just ice crystals. Jet engine exhaust composition will vary with fuel and engine and will typically hold a small cocktail of other products than water. Therefore a contrail is a chemtrail as jet engine exhaust is pollution.

    4. The skies have visibly changed, especially this last decade. You must surely agree?? Contrails have existed since flight began but these days they are truly overbearing.

    5. The atmospheric pollutants released by jet aircraft WILL reach the ground. When someone looks up at the sky and sees a criss-crossing grid across the horizon it is reasonable to assume the possibility that particles could be falling upon them from contrails originating hundreds of miles away many hours or days before.
    You see, if there is air travel there will be air pollution that descends to earth.

    Uncinus…whether we are referring to contrails or chemtrails we should agree there is cause for concern due to the scale of the contrail phenomena and because future environmental impact is impossible to accurately gauge.

    Thanks again.

  64. patthecat says:

    i should have put Uncinus et al…lots of you have made valid points to debunk a lot of questionable opinions that usually appear to stem from lack of understanding. Having said that I also think most of you are probably missing the points I wrote above 😉

  65. patthecat says:

    Aerosols, on the other hand, scatter or absorb solar radiation and prevent it from reaching the
    Earth. This has a net cooling effect. Together, emissions of greenhouse gases and aerosols destroy the existing radiative balance of the atmosphere and alter the heating and cooling rate of the Earth.
    In view of the aviation impact on the atmosphere, the following gaseous species can play the most important role: NOx (NO+NO2), HNOy (HNO2+HNO3), SOx (SO2, SO3), H2SO4, HOx (OH, HO2, H2O), COx (CO, CO2), and nonmethane hydrocarbons. The elements of NOx and HOx groups participate in the catalytic cycles of ozone destruction and the abundance of the species HNO2, HNO3, and NO2 as well as H2O can results in a broadening of the polar stratospheric cloud formation areas due to appearance of additional HNO3 and H2O in Polar Regions. The element of COx group (especially CO2) and hydrocarbons are greenhouse gases and affect the Earth’s radiative balance.
    Besides the gaseous species, aircraft engines emit aerosol particles and aerosol precursors. Soot and metal particles are directly emitted by aircraft engines. Soot particles are believed to be the most important aviation aerosols impacting contrail and cirrus cloud formation.

    Gaseous and Particulate Emissions with Jet
    Engine Exhaust and Atmospheric Pollution
    A.M. Starik

  66. captfitch says:

    All valid and true points. It takes some reading but I think we’ve addressed all of these in the past.

  67. SR1419 says:

    Hi patthecat-

    You do have valid points and no they haven’t been missed-I think they have all been addressed at some point over the years…but since you asked 🙂

    1. The amount that these man made cirrus clouds “geo-engineer” appears to be still uncertain. do they block more heat than they trap? This IS a genuine issue and is being studied intensively as the numerous scientific papers will attest…but in my humble opinion the potential “geo-engineering” of contrails is small in comparison to other man-made potential sources of “geo-engineering”.

    2. Its kind of a stretch to go from admitted “spraying”- ie: low level applications of pesticide etc…to a global, clandestine operation over a decade. No admitted spraying involved using persistent contrails…and since contrails have always behaved this way WHAT is the evidence that now something else is going on?

    Don’t forget – the entire premise of the “chemtrail” theory is based on the idea that contrails DON’T persist, spread and cover the sky in haze…So, the entire theory is based a FALSE premise. So, I fail to see how localized campaigns to eliminate pests or test pathogens 60yrs ago is evidence that a persistent contrail is actually something else.

    3. yes, semantically a contrail is a “chemtrail” since it contains chemicals- as is the exhaust of your car…and even your breath for that matter.

    But still that bears no credence to the idea that its really a global, clandestine operation by the “NWO” to (insert pet purpose here)…

    4. There are more contrails than ever before that much is true…overbearing?? thats a value judgment that I don’t really ascribe to. Where I live, I go weeks and weeks without any contrails…hard to call that overbearing. Some days the sky is filled with them.

    5. I am far more concerned by the ground based pollution than I am aircraft pollution. You should be too.

  68. TheFactsMatter says:

    “5. I am far more concerned by the ground based pollution than I am aircraft pollution. You should be too.”

    Amen to that!

  69. patthecat says:

    Hi SR1419…thanks for responding.

    1. okay so you admit the fact…good.
    2. You are badly informed…i’m not talking about 60 years ago.
    The military have admitted such operations, for example FOI requests reveal the UK was routinely sprayed with experimental biological and chemical weapons for decades.


    Nearly 40 years of secret tests. This is what they will let us know, reluctantly, but they have also admitted this is presently ongoing…for our own protection.

    3. Thank you for admitting that a contrail is a chemtrail. You shouldn’t tar all with the same brush. Not all chemtrail theories are the same. It’s not all NWO paranoia.

    4. You are lucky to live where contrails are rare. This site contains a lot of evidence that shows they have dramatically increased. In the UK it is far more prevalent than for you. The Icelandic volcano that shut down airspace made the phenomena all the more apparent by its absence.

    5. All forms of pollution are concerning. Air travel is no exception. Don’t forget that ground based pollution has been targetted and legislated against for centuries. Smog? When pollution becomes highly visible the public demand action.

  70. TheFactsMatter says:

    1) No, he didn’t “admit the fact”. He was trying to show you that the claim that persistent contrails are intentional “geoengineering” is ridiculous. There aren’t enough of them to do any more harm that any other cloud. And there isn’t any evidence that they have anything to do with “geoengineering”. It’s nothing more than speculation. He’s also making the claim that there are MANY other things we do, as far as polluting our own planet, that we SHOULD focus on!

    2)Yes, 60 years ago there was some testing on the unsuspecting public. It happens much more often than most people assume and has happened more of the years since. Especially with military personal. What does this have to do with the trails in the sky?! “They” could EASILY “spray” something into the sky and we’d never see it. Why would they make OBVIOUS trails in the sky that OBVIOUSLY come from the jet engines?! Why would they “spray” it in areas that are so cold that it turns whatever they “spray” into a man made cloud?! One would think they’d want what they “spray” on us to reach us…instead of floating over our heads only to eventually dissipate and fall to earth hundreds of miles away. The claim is absolute nonsense and requires a bit more evidence that what is out there. Well, it requires more evidence for ME to believe it. Some people will accept it as fact with nothing more than visual “evidence”. And THOSE people certainly understand VERY little about science. There are no assumptions and conclusion jumping in science! NONE!

    3) What you “believe to be “chemtrails” are only persistent contrails. Yes, they contain some “chemicals” in the form of combustion gases and H2O vapor. If the trails from the planes are “chemtrails” then so is the exhaust from buses, cars and trains. In fact, I fear the exhaust from buses cars and trains a million times more than I fear what’s in a persistent contrail. So should you! If you were a bit more informed, you would.

    4) The funny thing about that is the volcano produced tons of condensation nuclei in the form of sulfur compounds . There should be MORE contrails than ever before…. for a while anyway. Had the planes flown through the dust in the air, they would have created many more persistent contrails than usual.

    5) “All forms of pollution are concerning”

    You got THAT right! But, it’s better to focus on the ACTUAL concerns we face instead of the absurd notion of “chemtrails”. It never ceases to amaze me that so many people ignore the fact that our oceans are filled with bits of plastic that are actually killing of millions of birds and fish while they get sore necks staring at man made clouds. have you looked at the side of the road?! In my community, there seems to be many people who “believe” that throwing their trash out of the window onto the side of the road is acceptable trash disposal. Yet, there is a HUGE shortage of people to help clean it up because they are too busy looking up at the sky and whining about man made clouds (that, or they just don’t give a shit about the trash! Why?!) . Again, focusing on the absurd while completely ignoring the REAL problems we have right down here. It’s just plain SAD!
    What we see in these trails is NOT “pollution”. It’s water vapor. Yes, as with all exhaust, there are combustion gases. But, up there…where the air is saturated and very cold, any added moisture (like, the steam from a jet engine) will behave in a VERY predictable way. And it does. I see EXACTLY what I expect to see behind these airplanes. You see the same thing I see, but you don’t expect to see it, because you don’t understand what you should see! Who’s fault is that?! Sorry, the science is 100% solid in this matter. If you have ANY evidence to refute the well known and understood reality of the trails, please present it! I keep waiting for such evidence…but, it never appears!

  71. patthecat:

    So effectively we have second-hand geoengineering as a result of air trafic, would you not agree?

    You are playing with semantics here. Geoengineering implies something deliberate which is why it was put in quotes in the responses above. Contrail cirrus do affect the thermal radiation budget, and contribute to the global climate. Nobody disagrees with that.

    The real theory posed by the “chemtrail” theorists is if it’s deliberate in any way. There’s no evidence to suggest that it is. Contrails have always done this, and nothing has changed in the last several decades besides: more air traffic, bigger more efficient engines, and jets flying higher and closer together.

    Are you really trying to claim anything besides “planes pollute”? Because nobody is disagreeing with that.

  72. HaDi says:

    Coul you post a link to the german source of this interesting experiment made by DLR, please?
    I didn´t find at the DLR-Homepage…

    Shown below is a photo taken from the research aircraft Falcon of the German Aerospace Center (Deutsches Zentrum fh r Luft- und Raumfahrt (DLR) at about flight level 33,300 feet of an Airbus A340 with contrails (left) and a Boeing 707 without contrails (right). This illustrates a scientific effort to evaluate the effects of different engine characteristics on contrail formation.

  73. JFDee says:

    This might be what you are looking for:


  74. TheFactsMatter says:

    That’s a great link JFDee.

  75. JFDee says:

    It was Google who found it 🙂

  76. I’ll link it in the article. Thanks!

  77. HaDi says:

    @Uncinus, thanks for the link

    Obviosly this was an article for an english magazine, so there is no german version that I tried to find.

    btw: There are around 80 articles about contrails (“Kondensstreifen”) on elib.dlr.de. Most of them in german language. A lot of arguments against Chemtrails 😉

    btw2: Thanks for this interesiting blog…

  78. JFDee says:

    @HaDi, are you familiar with the German “chemtrail” scene?

    I’d be interested to learn where the main meeting points are.

  79. MikeC says:

    TFM scribed thus:
    “What we see in these trails is NOT “pollution”. It’s water vapor. Yes, as with all exhaust, there are combustion gases.”

    Yep – and they are there whether we see the water vapour or not – the pollution in hte form of various Nitrous and Suphur oxides comes from all jet exhausts – much less in modern jets than in older ones, but it is still there.

    as an aside the amount of enginering that goes into jets to reduce pollution/increase combustion efficiency is quite amazing – the design of the nozzles that spray fuel into the combustino chamber & of the combustion chamber itself are quite intricate in order to obtain even the smallest efficiency increases.

  80. Kate says:

    TheFactsMatter wrote: “There aren’t enough of them to do any more harm that any other cloud.”

    Ummmm…I’m not sure what part of the world you live in, but some of us are almost constantly under the shadow of these man-made clouds. How can you possibly say, full of confidence, that it’s not harming anyone???

    Sure, ground pollution is a huge concern. But ALL pollution causes a negative impact, if not now then certainly in the future.

    Also, has anyone considered the impact of these man-made clouds on Vitamin D levels?

    Vitamin D deficiency (which is far more widespread than many people realise) is linked to increased cancer risk, osteoporosis, decreased immunity, etc etc…I don’t need to be a scientist to know that all of these things are on the increase. Sure, food, lifestyle and ground pollution all play a part, but doesn’t air pollution also add to our toxic load??

    So please don’t say that they are no more harmful than any other cloud, because you cannot possibly know that.

  81. A plane produces the same amount of pollution regardless of if it leaves a contrail or not. The persistent contrails are no more pollution than the short-lived contrails. So what you are seeing is extra cloud cover.

    The minuscule reduction in total sunlight is going to have a far smaller affect on total vitamin-d production than regular activities (particularly how much time you spend outside), skin color, diet, and location.

  82. MikeC says:

    Kate the chemtrail hoax isn’t about aircraft producing pollution – no one here doubts that aircraft produce pollution.

    Or even that aircraft pollution may be “punching above its weight” in terms of climate change (the current theory seems to be that it is about 2-4 times “as bad” as ground level polution – Aviation and Emissions Trading, Oct. 12, 2007 (http://www.euractiv.com/en/transport/aviation-emissions-trading/article-139728).

    Nor even that contrail induced clouds are “extra” to “natural cloud formation and may have some effect on climate.

    That’s not what the Chemtrail hoax is about – although I suspect it may start veering that way since that is actually an arguable position.

    The chemtrail hoax is that something is being deliberately added to the atmosphere AS AN ADDITION TO aircraft fuel (& hence exhausts), or as a seperate spray, or somehow else, to deliberately change the climate, or to kill us all, or some other purpose, by a conspiracy that seeks to prevent us knowing what they are doing.

  83. TheFactsMatter says:

    “Ummmm…I’m not sure what part of the world you live in, but some of us are almost constantly under the shadow of these man-made clouds. How can you possibly say, full of confidence, that it’s not harming anyone???”

    Because I understand the science.

    If you’re concerned about vitamin D, take a supplement or drink milk. I would also suggest that you use your government in the way it’s meant to be used and ask that someone look into the potential effects of the lack of sunlight in your area. Also, are there any instances of vitamin D deficiencies in your area? Is there a spike in ANY illness that can be attributed to the supposed lack of sunlight? This is the info you need to arm yourself with if you want to make a claim that there is a problem. Without that information, you are speculating and making assumptions. My initial claim is based on the lack of evidence that there IS a problem. How much sunlight is too much, how much is enough and how much is not enough? People spend varying amounts of time outside…some never go out, is there any evidence that the trails limit the sunlight enough to make a difference?

    By the way, I’m from the Boston area (western suburb) . And I have seen these trails through my entire life. Sometimes, if the conditions are right, the sky becomes overcast. This is an area known for high tech and medical research. If there WERE a problem with vitamin D deficiencies, I assume I would have heard about it. Then again, there are people out there that believe the government hides such information from us. I don’t happen to be one of them.

  84. Loose end says:

    This may sound as a silly question, but, when a plane cruises, do all its engines have identical loads? That is, would the parameters and amount of exhaust be the same for each engine or not?

  85. I think they usually do. But they don’t HAVE to, like this: 0% on the right engine:


    Delta flight 629 with Engine out – zoomed in.

    View of an “Engine Out” situation for a Boeing 757 on route to San Francisco from Atlanta. The plane landed safely in Memphis. This photo was probably taken moments after engine failure.

    The location of this photo was 75 miles SE of Memphis International, in Mississippi.

  86. Loose end says:

    Thanks. This is what I suspected, when I watch a contrail of a two-engine jet dissipating asymmetrically. Like if one engine stream was notably denser than the other.

  87. MikeC says:

    IIRC from my airline time, a few years ago now to be sure, airliners can and will have varying throttle settings on engines to get the same power.

    To explain – as engines deteriorate, the power they generate is kept up by the eimple expedient of pouring more fuel into them through having a higher throttle setting to generate the same thrust.

    So the power (load) would be teh same, but het exhaust would be a bit different – I can’t really comment on how much the exhaust would be different, but you are looking at different temperatures, more or less unburned fuel & pollutants from more-or-less efficient engines.

    Back in the days before computerised flight controls, when throttle levers were mechanically linked to engine controls rathe than electronically linked, the differnt positions of throttle levers were noted as indications of engine wear – I have vague memories of tech log reports along the lines of “throttles had to be staggered by a knob width the maintain equal EPR” (the knob on the top of the lever was a conventient measure – so stagger would be 1/2 knob, full knob, 2 knobs, etc., EPR = Engine Pressure Ratio – a measure of power from a jet engine not so much used now I think)

    Again IIRC……

  88. Kate says:

    TheFactsMatter…Actually, in my circle of friends only, there is an unusually high number of people who have been medically classified as deficient in vitamin D. Also, we only have to look at the incidence of cancer and osteoporosis – both of which can be linked to vitamin D deficiency, to see that there might be cause for concern.

    Yes, of course there are all kinds of different factors involved, But you clearly stated that cloud cover caused by planes cannot harm anyone. You could not prove such a thing – how would you possibly measure all the variables? Tell the truth – you THINK that those clouds would not harm anyone, but you cannot know for sure. Lack of evidence does not necessarily show evidence of lack…

    (By the way, was that a drink of pasteurized, homogenized milk??? Thanks, but no thanks…)

  89. MikeC says:

    How about some evidence that there is actually harm being done, other than scaremongering?

    It takes an almost trivial amount of sunshine to produce adequate vitamin D – http://nutrition.about.com/od/askyournutritionist/f/sunlight.htm

    “Your body makes vitamin D when you are exposed to the ultraviolet B (UVB) rays in sunlight. You probably need from 5 to 30 minutes of exposure to the skin on your face, arms, back or legs (without sunscreen) twice every week.”

    What is the evidence that anything mankind is doing to the clouds is making it difficult to get this amount of exposure?

    As opposed to, say, lifestyle choices such as covering up all the time or just not getting exposure to the sun?

    There are a number of other factors of course – obesity is a major one apparently, so are some kinds of kidney and intestinal conditions.

    And then there’s the added factor that what constitutes “sufficient” Vitamin D seems to be a matter for debate too – see http://en.wikipedia.org/wiki/Vitamin_d_deficiency

    Why have you decided that it is contrails that are the cause?

  90. MikeC says:

    Oh and another thing – glass blocks beta radiation required to generate vitamin D too – so if you ware sitting in the sun in your car or behind a window you are not getting anything from it either.

    Plus if you’re in the Northern Hemisphere ATM then I believe there may be a dearth of sunlight! 🙂

  91. MikeC says:

    oops – it seems a previous message of mine got lost in the ether – I had said, more or less, since there are various factors, why pick on clouds?

    The amount of sunlight required to generate enough Vitamin D is pretty minor – 10-20 minutes, twice a week – it is more likely that lifestyle choices are makign a difference than a very small % of extra cloud.

  92. Yes, the place you live it (as in say, Seattle vs. Los Angeles) has vastly more effect on your sunlight exposure than the minute variation due to contrails. Even if contrails blocked 50% of the sunlight, then you’d still be getting more in LA. So why are the people in Seattle not sick?

  93. (Sorry MikeC, for some reason it keeps flagging random posts of yours as spam)

  94. Kate says:

    I’m simply raising it as a POSSIBILITY that it may be one of the factors affecting our health, in response to the comment that man-made clouds are “no more harmful than any other cloud”.

    Apparently “the facts matter” so perhaps the writer should begin such statements with “I think” or “it is my opinion” rather than stating them as fact…

  95. TheFactsMatter says:

    “Actually, in my circle of friends only, there is an unusually high number of people who have been medically classified as deficient in vitamin D”

    Sure… Your claim is ALL I need to believe you. I accept everything you write as fact because I’m a gullible mush-mind. Happy?!

    “But you clearly stated that cloud cover caused by planes cannot harm anyone. ”

    And I STILL see no evidence that it does. Do you have any? I’d be glad to take a look at it. The “possibility” may be all YOU need to accept something as truthful….I require a bit more. There are an infinite number of “possibilities” in this world. Where does it end for you?! There’s a “possibility” that being within 10 feet of another human being can cause instant death but we don’t live our lives worrying about that possibility because there is no evidence to support that belief. Just as there is NO EVIDENCE to support the belief that these trails “may be” harming us in any way. If you want to live your life wondering “what if” about everything, go for it…but don’t criticize those of us who REQUIRE just a bit more evidence BEFORE we make our conclusions.

    “Apparently “the facts matter” so perhaps the writer should begin such statements with “I think” or “it is my opinion” rather than stating them as fact…”

    As soon as the chemmies do it, I will. Deal? And honestly, you SHOULD require better evidence before you side against the well known and understood facts in this matter. You know, the facts about these trails that have been understood about this subject for 100 years.

    Go ahead, criticize me for being sensible. I expect nothing more from a chemtrail hoax supporter.

    Drink your raw milk! Enjoy! But, when/if you get sick, please don’t blame the trails in the sky. Remember, there is a “possibility” that the raw milk will harm you.

    “Lack of evidence does not necessarily show evidence of lack…”


  96. MikeC says:

    Man made clouds can only be more harmful than natural ones if they are significantly different to natural ones in a way that is harmful.

    AFAIK all the evidence shows they are not significantly different in such a manner, therefore it is perfectly correct to say they are no more harmful.

    Of course if you can show that they are significantly different then by all means do so.

  97. MikeC says:

    Uncinus – AFAIK that’s the only one that has not posted straight away?

  98. JFDee says:

    the main base of your assumptions is that the “covered sky” is caused by the contrails, or – vice versa – that the sky would be perfectly clear without them.

    But a covered or hazy sky can obviously happen without anthropogenic influences, right? Naturally?

    So we have a chicken/egg problem here: contrails make hazy condition – or hazy (humid) condition favours contrails.

    How can you tell the difference?

  99. Alexey says:

    “So we have a chicken/egg problem here: contrails make hazy condition – or hazy (humid) condition favours contrails.”

    No, we do not. It is humid condition favours both “hazy sky” and contrails. This morning I have seen plenty of contrails, none of which is persisted however, but by the midday the sky has become hazy anyway.


  100. Kate says:

    But do you have evidence that it DOESN’T??? Do you see what I mean. THere is no point using the science one way, if you aren’t also going to use the science from the other angle too…

    Apparently it is okay for you to question any comments I make, and say that my word is not enough for you to believe it – you need proof!!, but I am not allowed to do the same? Talk about shoe on the other foot.

    Why do you accuse me of being a “chemtrail hoax supporter”? I have not mentioned the word chemtrail. But you have – several times. I suppose you have evidence to back up my status as a chemtrail hoax supporter, too? After all, we can’t just take people’s word for these things…

    Has anyone actually done the studies to show whether increasing air-traffic, increasing air-pollution (FROM AIRPLANES) and increasing cloud cover (FROM AIRPLANES) is affecting our health at all? If so, show us the evidence so that we can judge for ourselves.

    I was trying to point out that the statement about man-made clouds causing no harm should be backed up with evidence, or it should be clearly stated that it was the writers opinion, but it seems no-one is willing to do this, instead you are all busy defending yourselves and pointing the finger at all the other factors, so I think this conversation has become pointless, and, quite frankly, a waste of time.

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