Here is a question. How does a 53% increase in air traffic from the 90's to today account for a roughly 5000% increase in(edit) "persistent contrails". I say "roughly" 5000% because in my observable area there were no chemtrails in the 90's, now a days you will see an average of at least 50 a day. Some days you dont see any, some days you see WELL over 50 or so many that you cant count.
The last I heard, air traffic was
doubling every 15 years, which is an
increase by 100%. That's exponential growth, such that air traffic has increased by
5000% since the dawn of cheap jet passenger travel at the end of the fifties.
The other part of the conundrum is that the passenger aircraft making the dense trails which have been (wrongly) given the name "chemtrails" are doing so in
supersaturated layers in the higher troposphere. These are water-vapor-saturated layers which, due to their stillness and non-turbulence, have managed (over a period of time) to absorb a larger amount of water vapor molecules (by diffusion from below) than they can possibly sustain when a plane barrels throughout them at 800 feet per second, trailing hot steam, CO2, and billions of carbon-based molecules generally bearing the designation of "UHCs and SOOT".
The amount of water per unit volume air isn't THAT great: at 35,000 feet and -40 deg C not a lot of water is needed for supersaturation. (It's very different at ground level). So when the planes fly through a supersaturated layer seven miles up they leave heavy trails of frozen ice crystals with a central molecular impurity which increase in weight sufficiently to fall
en masse out of the layer in minutes.
These trails don't desaturate the layer (though they may de-
supersaturate parts of them) because they are tiny with respect to its size, and they fall quite quickly out of the layer which produced them. These ice crystal trails are going to have to fall a couple of miles before they enter air which is above freezing temperature. But they can spread up to ten miles wide by the time they have done this. So where, say, in the sixties you might get a single huge trail ten miles wide, now, all other things being equal, you would see SIX of these trails. Six trails ten miles wide - and the whole of your sky could be white.
So basically it IS the increase in air traffic which accounts for this dramatic change in appearance. I have watched the sky over the Home Counties "white out" since the sixties, as long-distance air routes have existed and intersected there in all that time. The residents will tell you about living beneath a triangle of white (with blue skies on the horizons) for at least the last FORTY years - on occasion. These days it's a bigger triangle - on occasion.
The only way you can sometimes tell there's a supersaturated layer up there, is when it is already carrying some natural cirrus. And, of course, when a plane flying through it produces a dense trail. Otherwise,
supersaturated layers are invisible.
Cirrus clouds only exist stably in saturated air. And supersaturation can only happen to already-saturated air. When you see cirrus clouds you are looking upwards through a transparent troposphere into a transparent layer of saturated air with either or both the layer boundaries delineated by newly-forming ice crystals which
will itself become supersaturated over time if it isn't shaken or stirred.
So, when you see cirrus, expect trails. Horsetail cirrus, thinnish trails. Cirrostratus, heavy trails. (Because horsetail ice clouds are being whipped up, while flat strata ice clouds are obviously at peace).
Horsetail cirrus seems to be caused by the confluence of layers traveling at different speeds and directions, one of which must be
saturated. Cirrostratus forms when a non-turbulent
saturated layer loses solar illumination at sunset, or a layer is made to gain height. Either way, that's by
cooling. When a saturated layer is made to cool, it must either supersaturate, or precipitate out ice crystals, which it will certainly do if it is turbulated. The more it cools, the less stimulus it needs to do this, until finally it needs none. That happens above eleven miles up - three miles above passenger aviation.
Water vapor doesn't really feature above that altitude, which is why Edward Teller proposed "chemtrails" to be used at 80,000 feet*. Water washes out those sorts of particles to earth remarkably quickly below that altitude. Check out the lifetime of the dust from a large volcanic eruption.
Well, Teller's main aim would have been to see to it that the materials stayed up a long time to do the job of reflecting the sun's ray back into space - hence the 80,000 feet (16 miles) required. There's no point in putting it up for a couple of weeks.
* Unachievable, of course.