#AGU15 Accidental Geoengineering? Airline traffic may help create an icy haze that’s brightening U.S. skies

Jet contrails as seen by satellite. Credit NASA Langley Research Center

Jet contrails as seen by satellite. Credit NASA Langley Research Center

SAN FRANCISCO, CALIFORNIA —The data just didn’t seem to make sense. That’s often the story right before scientists make a leap in understanding. In this case, scientists had some evidence that skies in the continental United States have been brightening, after several decades of so-called “dimming.”

Brightening and dimming are overly simplified words that signify increases and decreases in how much light from the Sun (measured as “irradiance” in watts/m2) reaches the planet’s surface—and these measurements are often analyzed under cloud-free conditions.

For the observed dimming under clear skies, convention would point to aerosols. Levels of these tiny particles, associated with pollution, had been rising for decades prior to the 90s and began falling after that thanks to pollution controls. That could make today’s skies brighter than those in the 70s or 80s—and it could also warm the climate, as more direct radiation reaches the surface.

But when Chuck Long, a Cooperative Institute for Research in Environmental Sciences (CIRES) researcher at the NOAA Earth System Research Laboratory, and his colleagues dug a bit deeper, something didn’t add up.

If the recent clear sky “brightening” trend were due to cleaner air and fewer aerosols alone, it should be accompanied by an increase in direct downwelling shortwave radiation, one part  of solar radiation reaching  the surface directly from the Sun. That didn’t happen, Long reported during the American Geophysical Union fall meeting in San Francisco.

Instead, Long and his colleagues found that at the continental United States sites they analyzed, direct downwelling shortwave radiation remained roughly steady between 1995 and 2007, under cloud-free skies. Rather, it was the diffuse shortwave radiation that increased. That simply couldn’t happen if fewer aerosols alone were the reason behind the brightening. If anything, fewer aerosols should mean less diffuse shortwave radiation, because particles in the atmosphere can bounce light around and back to space.

So the scientists dug deeper, and in a provocative new analysis, not yet published, Long suggests that a high-altitude “ice haze,” created by water and other emissions from aircraft, is responsible. “I’m talking about a sub-visual contrail-generated haze of ice, which we do not classify as a cloud but gives blue sky more of a whitish tint.” Long said.

The finding—if verified—could mean that we are in essence already conducting a geoengineering experiment on the atmosphere, adding ice particles that change the way solar radiation reaches Earth’s surface. Understanding the overall impact of those changes on warming or cooling at the surface will take more research, Long said.

The hypothesis has some circumstantial support in other datasets, Long and his colleagues have found: The  brightening trend is closely correlated with U.S. Federal Aviation Administration commercial flight hours during 1995-2007; those aircraft emit both water and the particles necessary to crystalize that high-altitude water into ice.

Moreover, a preliminary study using spectral solar data from an Oklahoma site shows that the clear skies had an overall “whitening” trend during the study years, an indication of increased scattering.

Professor Martin Wild of the Institute for Atmospheric and Climate Science at ETH  Zurich, Switzerland, has been tracking Earth’s changeable energy budgets. He and his colleagues detected upswings in sunlight reaching the Earth surface (i.e., “brightening”) since the mid-1980s, which marked a recovery from substantial downswings in prior decades, a discovery published in Science. “We care about dimming and brightening because these phenomena may not only affect global warming, but also affect plant growth, glacier melt, the water cycle, solar power, and much more,” Wild said.

Wild said he’s interested in the new hypothesis, which will require more investigation, but which could help researchers to better understand the origins of dimming and brightening, a phenomenon with broad environmental and socioeconomic implications.

CIRES is a partnership of N​OAA​ and C​U-Boulder.​

132 thoughts on “#AGU15 Accidental Geoengineering? Airline traffic may help create an icy haze that’s brightening U.S. skies

  1. Wow! Somebody actually cranked his neck and looked upward. I have been saying this for a long time.

    We complain about a trace amount of an invisible gas and its effect on the climate but ignore, for lack of a better word, “jet exhaust” which you can see is blocking a significant percentage of the sun’s energy and everybody ignores it.

    • Bring money. More research needed.

      Nah ! clouds don’t affect the amount of solar energy that reaches the surface, whether in cloudy or cloud free skies.

      It’s the CO2 wot does it.


    • I would think that anyone who spends the majority of their days out doors would notice that blue skies are not near as blue as years ago–definite whitish tinge now-a-days.

      • When you say blue skies now have a whitish tinge, the blob on one’s neck should remember many of those skies were brown 30 to 40 years ago, much the same as South-East Asia’s now. So when comparing measurements over this period are we comparing apples with oranges.

    • The picture used to illustrate this article is BS. “Contrails” are too small to be visible from space. That said, I second your emotion, Elmer: “Somebody actually cranked his neck and looked upward.” (!!!)

      If they did, they’d realize someone has some ‘esplainin’ to do. …. It’s not passenger planes doing this — if it were, they would all be emitting and their contrails would be bunched along their flight paths. Also, these “contrails” don’t sublimate like ice trails do, they disperse, characteristically devolving first into a wider contrail with “barbells” at one end, which then slowly spreads to form a large, hazy off-white cloud at around 20,000 feet. Anyone old enough to remember what real contrails were like, before jet engines were modernized in the late ’70s/early ’80s, should realize these are not the same phenomena. I have photos taken at my house showing the life-cycle of these so-called contrails, but can’t figure out how to display them here; to see how the old contrails behaved, there is a John Wayne western somewhere that shows one anachronistically…..

  2. I have been surprised nobody has thought of putting additives in jet fuel to reflect sunlight and control climate change — given this data, it would seem a like a possibility?

    • NO, NO, NO, Not That!
      Airliners with chemicals = Chemtr**ls.
      A WUWT forbidden topic.
      I was going to suggest that WUWT allow a thread on the topic for Halloween, call it Scary Saturday, where we all tell our most frightening stories. This would be right at the top.
      But I chickened out. Maybe next year.

      • TonyL:

        It is not a “WUWT forbidden topic”. I provided a Guest Essay on WUWT that suggested using research (n.b. NOT adoption) of exactly that as a ploy politicians could use to show they were ‘doing something’ when they want to reverse AGW-policies but don’t want to be seen back-tracking.

        At present, politicians still have no excuse to avoid setting-up the harmful bureaucracies encouraged by the recent IPCC Conference in Paris. I still think the ploy I suggested is a good one: bureaucracies are difficult to eradicate and impossible to nullify.


      • According to the video the trails are ice crystals. The airlines don’t have to add chemicals. Just spray out a constant mist of water when they get up there. The mist turns to ice crystals, spreads and reflects sunlight back into space. With the constant airline flying over the burbs of Chicago in just one area every 2 minutes, they could put out a lot of crystals all day long. That would help with the city heat islands.

    • Airlines are in the paying passenger carrying business; not the experimental chemical pollution business.

      They are looking for was to increase efficiency ; not r ways to make the sky shiny.


      • george e. smith:

        Clearly, you did not read the link I provided because you write

        Airlines are in the paying passenger carrying business; not the experimental chemical pollution business.

        They are looking for was to increase efficiency ; not r ways to make the sky shiny.

        There is a cost to removing sulphur from aviation fuel. The suggestion was to leave it in.

        This would reduce the fuel costs and, thus, increase the profits of all airlines including those “in the paying passenger carrying business”.

        If you read the thread you will see sensible discussion of the suggested ploy was completely destroyed by people incapable of reading what I wrote before making silly comments on it.


      • richardscourtney: “There is a cost to removing sulphur from aviation fuel. The suggestion was to leave it in.”

        I think the main reason to remove sulphur compounds and other impurities from jet fuel is because at around 2,000°C they have a somewhat less than advantageous effect on the engine’s internal components.

      • No Richard, you are correct, I did not read the link. I did not intend to read the link.

        I think I said they are looking for ways to increase efficiency. Never said a word about cost.

        Unless the sulfur is a known jet engine fuel, I would think that leaving the sulfur in the fuel would increase the weight of the fuel, which would lower the amount of fuel they could carry, or reduce their paying payload capacity, which would lower the efficiency.

        Now in the American West, we have a whole lot of “Low Sulfur coal” which Bill Clinton put a hex on so we can’t mine it. This left his Chinese financier, with the largest source of so called low sulfur coal.

        Turns out that our low sulfur coal is only low sulfur per ton of coal; but on a sulfur per BTU basis, it is very high sulfur coal, compare to Eastern Anthracite coal. Our muck is glorified peat.


    • I cannot imagine the jet engine manufacturers approving “climate chemicals” in jet fuel, jet engines are designed for reliability and fuel efficiency, not crop dusting. If we were to ask jet aircraft to carry aloft climate engineering materials, I expect it would be added at the tail end of the engine, not the fuel nozzles. The biggest problem would be asking those companies to sacrifice payload, i.e., billable transport tonnage for a science experiment. I wouldn’t hold my breath for that occurring. Not to mention that I’m not sure we’re smart enough as a species to make well considered experiments in geoengineering which might result in changing the wrong climate conditions. Oops, we forgot to consider “X” (insert your catastrophic oversight here). When computer models mimic real climate data over a loooooong time period reliably, maybe we could discuss ideas then. It seems like we’ve a ways to go before that day arrives.

  3. The day humans start wih geoengineering we are really in trouble. Some will want more rain, some less, some hotter and some colder, some less wind or more wind. Who should decide, UN?!

  4. I remember reading an article many years ago, that argued that we could affect the climate by adjusting the altitude at which jets fly in order to maximize or minimize the formation of contrails.

    • Sure – as long as you pay the airlines to fly at less eficient levels. Oh, and don’t forget packing all the airliners into a few flight levels, and backing up all the traffic.

  5. The article a few days ago about the satellite that photographs the bright side of the earth started a train of thought; admittedly a short freight – engine, two cars and a caboose. What effect on solar irradiance reaching the earth’s surface do all the satellites and the much more numerous pieces of space junk have? I mean we’ve got decades of that stuff up there. I wonder how many square miles of absorbent and reflective materials. Now this, contrails. Where can I get a grant to study all this?

    • Re satellites/space junk and affect on solar radiance. I think the answer is a variation on “the sea is vast and man is small”. There are a lot of satellites and even more junk in orbit, but putting that stuff up there is VERY expensive and the higher one puts it the more expensive it gets. For most purposes like monitoring stuff on the surface, you don’t want to be too high anyway because being further away from what you are looking at just makes things harder. Anything much below 400km at it’s closest approach to Earth — be it a satellite, a fuel tank, or a dropped wrench — won’t be around for more than a few years due to drag. It’ll slow down, eventually re-enter the atmosphere and burn up or crash.

      There are maybe 20,000 objects in orbit and the problem with them is that they are travelling really fast (about 27000 kph) which means even a loose bolt or metal fragment can have a closing velocity of up to 54000 kph if it whacks into a satellite. Thats many times the velocity of even the most sophisticated anti-tank weaponry.

      As far as reflecting area, I think it’s probably equivalent to putting a few dozen modest automobile junk yards into orbit — no big deal I should think. But the impact thing is a looming problem

      There an article here: http://ccar.colorado.edu/asen5050/projects/projects_2011/buccino/ I didn’t read the whole thing, but I think it’s likely accurate.

  6. Hardly new news — there was a paper published way back in the 70’s dealing with this issue and also the fact that under some (not unusual) conditions contrails could and did “catalyze” cirrus formations, as contrails will often grow to become large cirrus layers. This observation dates back to WWII when the large bomber formations would leave massive contrail streams that would grow into cirrus layers large enough to interfere with the photo recon planes a few hours later. The 70’s paper dealt mostly with the effect these “artificial” cirrus layers might have on agriculture in the US Midwest, as the contrails grew from thin lines into substantial cirrus layers, reducing the light available to crops. I’ve observed this many times myself flying in the West and Midwest.

    • Keep in mind thought that a lot of time contrails evaporate or are non existent. The only time they grow (and get the chemtrail believers all excited is when the flight level air is saturated or supersaturated. On days when a deep, refreshing Canadian air mass floods through the area, contrails don’t have a chance.

  7. I don’t know how studies are dispersed geographically, but I’d expect a lot more air traffic and contrails (or ice haze) along the eastern seaboard due to the population density and central US due to the route density than some place like New England.

    From property I own on a mountainside in New Hampshire, there is a lot of traffic with Europe, but that tends to be in a pair of waves daily, morning for traffic to Europe, and afternoons to traffic to the US. My “Plane Finder” app is showing the start of the afternoon wave is in Maine. Currently there is no commercial traffic in NH north of Concord except for a Cessna at 20,000′ entering Maine and a Lufthansa LH418 from Frankfurt to Dulles that’s 16,000′ above the Cessna.

    Hey researchers, come on up next summer. Lots of sky here, if you hire a logger first. :-)

  8. [My first letter to an editor:]
    In the USA during the 1960s, supersonic transport (SST) was being considered and discussed widely. Someone wrote in Popular Mechanics (or some such) about the aircraft producing water vapor at high altitude and that wasn’t a problem as it isn’t a pollutant. I was taking a chemistry class at that time and so responded that regardless of the chemical, if it was introduced into a place where it was not, it ought to be considered skeptically until shown otherwise.

    Thanks for doing the reporting on AGU!

  9. It is my understanding that aircraft are only responsible for about 2 percent of anthropogenic CO2. So the volume and mass of these emissions is pretty darn small. Hard to believe they could significant impact global climate without some profoundly dramatic amplification effect (e.g. precipitating cloud formation). Might be possible but I’m definitely skeptical!

  10. In the early seventies, there was a lot of concern among pilots that “the horizon was disappearing.” The soot from jet engines was causing darkening, and the maximum darkening was when trying to see the horizon.

    What is different today? Most commercial jets, even those flying in those days, have been re-engined with fan-jets, instead of turbo jets. The fan-jets are more efficient, and part of that increased efficiency is burning the fuel more completely. (They even ate up the soot that other planes left there, especially afterburners on high performance fighter jets. ;-)

    So now the exhaust is air, water, and CO2, with the brightening effect noted. This is actually the second geoengineering project. Or the sixth or seventh? Desertification, widespread agriculture in formerly desert areas, dams and other water diversions, “reclamation” of swamps and waterfront property, and so forth.

    We can’t get away from the fact that humans are changing the earth, we can just try to do it more intelligently. This includes doing something about CO2 levels. Not for any reason to do with global temperatures, but because it is making things harder for infants, the elderly and those with breathing problems.

    • A couple hundred PPM isn’t going to have any effect on breathing problems. If you sit in a room for awhile by yourself or with others, the CO2 levels will be much, much greater than the atmospheric level at about 400 PPM these days. If that bothers you, stay outdoors.

      • Actually, the change from indoors to outdoors and vice-versa is a problem for some, not many, people. The how often you breathe is determined by the partial pressure of CO2 in your lungs. But water in the air (or of course in your lungs–pneumonia) can absorb some of the CO2, while reducing the amount of oxygen available. Under normal circumstances, your body adjusts to the (current) CO2 level to regulate O2 levels. If the levels change too much and bounce back and forth, well you get sick building syndrome.*

        So, no, I am not worried about 400 ppm levels, or even 600 or 700 ppm. Get too high though, and designers of large buildings are going to have to start putting in CO2 meters and regulation systems. Get up towards 1000 ppm, and everyone will have CO2 scrubbers in their homes. (Well, not everyone. But where I live, in New Hampshire, would it be worth it if it prevented one cold per winter per child?)

        *Flame retardant: Not all, or even a significant fraction of SBS is caused by fluctuating CO2 levels, and today most building design rules call for constant ventilation, even when no heating or cooling is being done. If the systems break down, then you have problems. A few years ago there was a heat wave in Paris in August. Not quite everyone in Paris takes vacation in August, just those with jobs. ;-) One of the reasons that so many elderly died was a woeful lack of HVAC repairmen, and you can imagine how their priorities were set.

    • Everything living (or decaying, or corroding) is changing the earth. Differences and change drive everything in Nature; in fact, difference and change IS Nature!

    • Robert wrote:

      “This includes doing something about CO2 levels. Not for any reason to do with global temperatures, but because it is making things harder for infants, the elderly and those with breathing problems”

      Ha! Really, C02 going from 300 to say 500 ppm is a problem for those with breathing problems? Lets put some numbers to that.

      Any pilot knows the rule-of-thumb that from 0-10,000 ft for each 1,000 feet you climb you will see atmospheric pressure drop about 1″ of mercury out of 29.92. That is about a 3.3% reduction in pressure. Going from 300 to 500 ppm over the course of a lifetime will displace 0.02% of the air we breath, or less than 1/100 of the pressure change due to climbing 1000 feet.This is the equivalent of moving about 6 feet (2 meters) upward in the air column. So you are saying that your baby will suffer it you take her halfway upstairs in your house? Your saying that your elderly parent must live in your basement because he could not survive the altitude on the main floor?

      This is what happens when folks want to rule the world with feelings rather than knowledge.

  11. [Comment deleted. “Jankowski” has been stolen by the identity thief pest. All Jankowski comments saved and deleted from public view. You wasted your time, sockpuppet. -mod]

  12. Well, we pump some 13 million liters of aviation fuel (ie diesel) combustion products into the upper atmosphere every day. So I suppose as experiments go, that is one hell of an experiment. ;-)

      • Jet A1 about 0.8. Kerosene about 0.81. Car diesel about 0.83 (according to Chevron).

        Put it this way, if you put diesel in a jet it will work just fine. In fact, the Avco 502 jet for small regional jets was derived from the AGT1500 jet that powers the Abrams tank. And that runs on any fracionation from petrol to marine diesel. In fact, an Auz airline did run a jet on avgas once, but don’t tell anyone.


  13. Maybe this could partly explain the difference in ice growth or loss between poles since there’s almost no air travel over the Antarctic.

  14. [Comment deleted. “Jankowski” has been stolen by the identity thief pest. All Jankowski comments saved and deleted from public view. You wasted your time, sockpuppet. -mod]

  15. They’re clinging desperately to their up-welling/down-welling radiation!
    Now they’re throwing in vapour trails to conceal the fact that this was always a meaningless metric. Or rather a negligible one. There would only be a few days of the month during certain seasons where the US sky would look like the one in the main picture above. Angels dancing on pinheads, again.

  16. If you don’t like the look of a scientific theory, you only have to wait a few months these days, to find that it has been supersede by yet another new theory. This helps keep science moving and scientists employed.

  17. Are there any conclusions are to whether a side-effect of this High Altitude Haze is an increase in reflection of radiation back into space i.e. lowering temperatures (bad for AGW by CO2 skeptics)
    an “insulating” effect (like when it’s warmer when it’s cloudy) therefore keeping temperatures higher than would otherwise be the case (bad for AGW by CO2 proponents) ?
    “Send more money”

  18. NASA scientist admits to spraying Lithium to measure earth’s electric currents (rivers of energy in the sky)

  19. I’m not understanding this. They say there is more total downwelling sunlight at the surface. However, the direct downwelling sunlight has stayed the same.

    They explain this by saying that the diffuse downwelling sunlight has increased.

    I’m not clear about how that happens. When diffuse sunlight goes up, direct sunlight goes down. So IF their claim is correct, then either the total cloudiness must have decreased, or the amount of sunlight absorbed by the the atmosphere must have decreased.

    What am I missing here?


    • Willis it is probably same effect I noticed some years ago. I found that I burned my skin more quickly on beach in Croatia under partly cloudy sky, with sun reaching max. around 60 degrees, than in Egypt under clear sky and sun 80 degrees high.
      It is about reflected sunlight from sides of clouds. Simply if sun is shining on you directly from hole in clouds and around sun you have a lot of white clouds you are receiving more radiation than from sun only and blue sky.
      It is of course balanced with some places under clouds receiving very little of radiation. It is something like cloud lensing.
      But I’m thinking under some circumstances, when sun is low and clouds are just reflecting light which is parallel with Earth it can be net gain.

      • I was on a mountain peak near the coast, about 6,000 feet alt. in spring time and a fog rolled over the top of the peak. It seemed warm and I took my shirt off for about 20 minutes. Got the most painful, serious sunburn I’ve ever had. Couldn’t even take a cool shower or sleep for 3 days after.

        UV Scatter in all directions in that fairly thin layer of fog. Amplified. Incoming and outgoing. Even got burned under my armpits a bit. And I wasn’t standing on my head. Was sitting on a rock.

  20. Perhaps I didn’t read carefully enough, but it’s not clear to me, does the study say albedo is increasing or decreasing?

  21. Well, natural extra-terrestrial factors must first be factored out before we leap to activities of man. The air interfaces with the sea over 73% of the planet’s surface. Under the moon at all times is an air-tide, in which the air, like the sea, daily undergoes changes in height. We know, for instance, that weather balloons float higher around perigeal new and full moon days, indicating a king (or spring) tide in the air around the same month-day as the sea. This explains why cyclones develop around perigees. Weather results from changes in the air-tide which is why there are weather cycles..
    Around full moon in daylight hours there is a ‘thinner air’ effect due to a lowered air tide until the moonrise around dusk. The thinner air during full moon daylight hours allows for more solar radiation to approach the ground without the encumbrance of an expanded and insulating air layer. It is why full moon to last quarter days over summer are hotter and more exhausting than other days of the month – they allow more heat from the sun to reach the ground.
    The sky is bluer when there is less sun glare. The extra glare produced by increased radiation over full moon days tends to wash out the blue. Conversely because the new moon is a day moon with the air tide “in”, new moon days present bluer skies.
    There may be other factors too, like strong aspects of Jupiter and Saturn which can add to a month’s sunspot count. Sunspots will also change blueness.
    Until more work is done in these areas we cannot begin to blame planes or other manmade factors for changes to blueness.

  22. …it was the diffuse shortwave radiation that increased. That simply couldn’t happen if fewer aerosols alone were the reason behind the brightening. …

    Long suggests that a high-altitude “ice haze,” created by water and other emissions from aircraft, is responsible. “I’m talking about a sub-visual contrail-generated haze of ice, which we do not classify as a cloud but gives blue sky more of a whitish tint.

    Maybe I’m not understanding their claim, but it seems they are saying that there is more “brightening” going on than can be accounted for by fewer aerosols alone, and that the “ice haze” from aircraft emissions are responsible for that extra brightening. How does high-altitude “ice haze” allow more sunlight to reach the surface than would occur from clear skies alone? White clouds, for example, let less light through, which cools the surface. So how does white ice haze do the opposite? It just doesn’t sound plausible to me.

  23. Nobody gets outside anymore.
    She’s the same bitch She’s always been.
    Wouldn’t have it any other way.

  24. Well this is my favorite subject for parsing. I have been observing chemtrail activity in the Hudson valley for ten years. I have always respected Anthony’s request we stay on topic in a thread and stay to the science. But again the subject of contrails and geo-engineering has popped up. I suggest that we need to know what exactly are we looking at in the photo at the head of this post? We see the south eastern USA from space and we see a number of lines of white stuff over the earth below. Fine, but, is this a time lapse photo? Or is this a milli second photo? If indeed a time lapse photo, how long a period of time. If not is this from a geo synchronous orbiting satellite? In any event i understand normal contrails last for a few miles behind a jet and dissipate due to sublimation, a chemtrail on the other hand will persist, often called “persistant contrails”. My contention after documenting thousands of hours of sky watching and photographing that indeed something is going on geo-engineering wise. Thus yes the calculous for CAGW must include deliberate inoculation of the upper atmosphere with aerosols for either experimental or deliberate purposes.

    • Ok, but what are “they” looking to achieve with this inoculation ?
      Mind control ?, it better not be liquor control.

  25. What about tiny droplets of sulfuric acid solution formed from borderline cloud/contrail formation conditions, and which usually don’t evaporate completely due to sufuric acid being hygroscopic? Increased coal burning in China would favor more sulfuric acid droplets. I think these droplets would have greater atmospheric lifetime than ice particles, but still generally short.

  26. Contrails consist of water droplets and as such are scattering the incoming sunlight, not absorbing it. The only thing that matters is therefore how they affect the total albedo of the planet. The first photo shows that they may have a small effect over areas without clouds at a lower level.

  27. Real time aircraft movements around the world
    this link is centered on Heathrow –
    (Hover cursor over plane for its call-sign, click for full details.)

    You can drag & expand map to give the whole worlds commercial aircraft positions & identify each one. Times out after 30min, just reload page.

    you can set for any location
    Hrs of fun ;-))

  28. I’m calling bogus on the lack of identification of the image of the contrails. It is NOT a photograph in the visual spectrum. And it is NOT a simple infrared photo either. Instead, it is an enhanced image that according to NASA “uses two infrared wavelengths to reveal contrails”.

    Be clear that I’m not saying that contrails have no effect on the weather. I’m just saying that, as is far too common in science these days, the image is picked because it gives an alarmist picture.

    Finally, the picture is from a study which is now 11 years old … see here for details.


    • Hi Willis, what ever the image is the head of this thread the subject has popped up again. I am old enough to remember real clouds, at least real natural clouds. The sky today is full of what I call forced clouds due to e deliberate spraying of aerosols in and around cirrus clouds. Every time a cold front rolls through the Hudson Valley the tell tale mares tail (cirrus) clouds that precede rain are ALWAYS sprayed. We have spay days here that are unbelievable. For me this is not conspiracy crap I looked up online at scary websites. This is real violation of our atmosphere and this geo-engineering scheme must be included in Climate Change modeling or CAGW prognostications or what have you. I have my own documentation in photography from the ground clearly showing chemtrails being turned on and off. Normal contrails do not that. Chemtrails then absorb the ice crystals from cirrus clouds and these form fuzzy sickly looking clouds that spread out and occlude sunlight. Routinely.

  29. Science is the approach to precision, especially in language. So I will say it. Chem-trails, contrails etc have NO effect on weather. Clouds have no effect on weather. Clouds ARE weather. What something is, has no effect on itself. It’s like saying the water makes the ocean wet. It doesn’t – the ocean is already wet.
    Also, the weather that we perceive, originates in the ocean. All rain comes from the ocean and most falls back into it. Yes, we may see clouds descending, but the water in them first came from the sea. Some vapour may have come from jets, but it would require an ocean-sized number of jet vapours to produce one rain event.

  30. Here’s an order-of-magnitude check.

    Burning jet fuel (kerosene) produces 1.1 litre of water for every litre of kerosene burned.

    There’s about 5 million barrels of jet fuel burned daily.

    There’s about 1.3E+13 cubic metres of water in the atmosphere.

    Jets add about 8.7E+5 cubic metres of water daily. This is about 0.00001% of total atmospheric water vapor.

    Surface area of the planet is about 5.11E+14 square metres. This means that the 8.7E+5 cubic metres of jet-water, if spread around the planet, would add about two milligrams (0.002 g) of water per square metre per day … as a comparison, a drop of water weighs about fifty milligrams.

    As a different comparison, a cumulus cloud typically has a water content of 500 milligrams per cubic metre …

    Now, this does NOT mean that contrails can’t have any effect … but it does suggest that although there may be local effects, the global effect is likely to be small.


  31. “Burning jet fuel (kerosene) produces 1.1 litre of water for every litre of kerosene burned.”

    No wonder the seas are rising :)

  32. I am surprised that no one has mentioned http://www.geoengineeringwatch.org where there appears to be a welter of evidence that chemicals, heavy metals etc are being sprayed from all types of aircraft and consequently affecting the climate.

    (Please don’t comment on chemtrails here, as it is against site policy. Thanks. -mod)

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