I would like to believe your account, but I simply don't recall this phenomenon until very recently.
People seldom recall things that have only a trifling significance for them. I don't recall the last three Buicks I saw on the road, either. You probably just weren't paying attention before. But now that you've taken an interest in this subject, you'll start noticing contrails everywhere. There is a well-known type of cognative bias that occurs when an old and ever-present sensation suddenly acquires a new signification for us: we start to notice it selectively, perhaps even exaggerating its frequency. This alone may be contributing to your increased awareness of contrails. Please continue to watch the skies, even recording your observations if you want. In a short time you'll notice that nothing unusual is going on.
How do you explain these persistent contrails during the summer in the middle of a 90 degree day?
The air in the upper troposphere is much, much colder than the surface level air, even on a blistering hot summer day. This is why there are snows on the summit of Mt. Kilimanjaro, and a semi-tropical forest on the plains below it -- on the same day.
The decrease in atmospheric pressure with increasing altitude alone will cause a parcel of air to cool by 5.38 °F per 1,000 ft. This is called the adiabatic lapse rate.
So, let's say that the surface temperature is 90 degrees in southern Indiana, elevation approximately 400 feet. That means that the air temperature at 26,000 feet, all other things being equal, will be...(90 °F) - (5.38 °F X ((26,000 - 400) / 1000 ft.))
...which is almost 140 degrees colder.
Of course it's not quite that simple. Assuming that the air is not perfectly dry to begin with (a fairly reasonable assumption), then at some point the rate of cooling will switch from the dry
adiabatic lapse rate to the moist
adiabatic lapse rate, which is slightly lower; however, we would not know when that point occured without knowing the original relative humidity of the air. Also, there is the fact that surface albedo forcing
would have warmed the air directly above the ground to a greater extent than solar forcing alone would have done. But these secondary considerations aside, you get the drift. The air in the upper troposphere is much colder than the air at the surface even on a summer day, and plenty cold enough to cause contrails.
Anyone who has ever seen a perfectly clear day become overcast/partly cloudy after they make their patterns in the sky knows darn well that it is NOT a natural phenomenon. All talk to the contrary is nonsense, however kindly or innocently offered.
Do you mean to suggest that commercial airlines -- who can scarcely make a profit to begin with, who are already taking every measure to cut weight and fuel consumption -- are not only loading up their planes with hundreds of additional pounds of chemtrail dust, but deliberately flying out of their way with their increased burden to make "patterns" in the sky, and that the longsuffering passangers with their GPS-equipped smartphones never notice the detour? And for what end, to make clouds? Now that is ridiculous.
As I've already stated repeatedly in this thread, the genesis of real, honest-to-God contrails is indeed a form of unintentional cloud seeding. There have also been attempts at intentional cloud seeding to generate rain, but research suggests that those attempts haven't amounted to much; and in any case, commercial airlines have nothing to do with the matter. But even supposing, per impossibile
, that the airlines were up there wasting time making clouds, absolutely nothing bad has resulted from any of this. The world is still turning, is it not? You've got a dubious murder weapon and no body. Case closed.
FWIW, if the chemtrail debunkers' explanations were legitimate/reasonable, you'd actually see MANY MORE "long-lasting contrails" above major metropolitan areas than you do on those days when the conditions are as their theory suggests. If, say, 100 planes fly over a certain area at over 26000 ft (which happens every single day in many areas) when certain conditions are in effect, why are there not just as many long-lasting contrails as there are planes in the sky above 26K ft? Uh, because that explanation is absolute hogwash.
Epic fail, Eamon. Utterly pathetic. The vast majority of the planes that you'll see flying over metropolitan areas will (obviously) be those flying into or out of the airport(s); hence flying at low altitudes, were contrails do not naturally form anyway. Once an airliner reaches its cruising altitude there is no particular reason for it to fly over a city; and since it will take the most economical flightpath toward its destination, and since most of the country is uninhabited, high altitude jets are not seen with any exaggerated frequency over urban areas, and there would be no reason to expect an especially large number of contrails to appear there. But if your theory were correct, then you might
see an escalating number of chemtrails at low altitudes, since flying low over an urban corridor would be the optimum way to disperse whatever nefarious agent you allege they're afflicting upon us, hitting the densest population centers at the least cost. That assumes, of course, that these maniacally brilliant manipulators of the world puppet-theater are not too stupid to camoflage what they're doing, so that even you can figure it out. In any case, trails at low altitudes would not (ordinarily -- there are exceptions) be contrails, although there is no reason to assume that they are malign. They might result from a smoking engine, a fuel dump, or a wingtip vortex. There is no reason to assume that trails at high altitudes are anything but contrails.
When you see 2 planes on the SAME DAY, SAME ATMOSPHERE, SAME HUMIDITY LEVEL, etc. and one of them is spraying a grid pattern, while the other leaves absolutely no trace in the sky -- that forces you to realize that something is up!
No two planes are ever flying through the same atmosphere or the same atmospheric conditions. The atmosphere is an unstable fluid with sharply divergent boundary conditions; i.e., atmospheric variables differ rapidly across space and time. That is why we have such things as clouds and weather in the first place. Without such divergences, the atmosphere would be nothing but a cold, uniform haze. Have you never seen a squall line before?
Any two planes that you see in the sky are likely separated by thousands of feet both vertically and horizontally; flight plans and air traffic controllers see to that. This means that they are NOT flying through the same atmospheric conditions at all. For you to suggest that they are literally "in the same atmosphere" is tantamount to you looking at the picture above and exclaiming, "Hey, I see clouds and rain in one region of the sky and clear skies in another. Something is up!"
Yeah, something is up alright. It's called scientific illiteracy. Fortunately, you don't have to let this happen to you. There is an abundance of good meteorological information available on the web. Try having a look. You can start here.