So, we hear a lot about they "mythical" chemtrail, but what many of us dont know is that contrails can have an adverse affect on climate themselves.
The main product of contrails are water and dust, both found from the jet engine exhaust.
Contrails form when hot exhaust gases are expelled into a super cooled environment, mixing with surrounding air. Under suich conditions the water
vapour rapidly condenses into water, then ice crystals. This happens in a fraction of a second, and is the reason contrails form a few feet the
exhaust rather than straight from it.
The concern with contrails is when they linger. Like natural clouds, the water vapour, or ice crystals feed off water already present in the
atmosphere, creating a chain reaction which can often create a sheet of cloud (which by this time is called cirrus). This can occur for hours, or
until the loud reaches a scetion of dryer air.
Now that we know that the main product is ice, lets examine the reflectivity of ice crystals in the atmosphere.
Its is a well known fact that fresh snow has the highest albedo of most of the kind ofs surfaces within the troposphere, at about 70 to 80%. Surface
Ice reflects approximately 30 to 40% of sunlight, while the ice found in cirroform clouds (include contrails, cirrus, cirrostratus, cirrocumulus, and
cirrus derived from contrails), reflects about 50 to 60% of sunlight, and sometimes up to 70%
Now considering the amount of air traffic over Europe and North America, imagine the amount of sunlight being reflected back out into space. It would
be an enormous amount.
Cirrus clouds also trap heat within the earth during the night. When cirrus is present, or even on a cloudy night...the temperature will not drop very
much. The difference between the maximum temperature and the minimum temperature is known as, the diurnal temperature variation. On cloudy days, the
diurnal temperature variation is very small. That means that the difference between the maximum and ther minimum temperatures will be very little. On
clear nights, the diurnal temperature variation is usually larger, as the long wave radiation brought in is not trapped by cloud cover, meaning the
earth cools quicker.
One major event, proved that contrails have quite an effect on diurnal temperatures, and climate. That was September 11th, 2001. Below are comparisons
of the north east USA before the terrorist attacks and after, when all air traffic but airforce one and its escorts were grounded.
Now while they are alightly different images, it should be apparent that contrails are having a great affect on the diurnal temperature variations in
the United States. On the three days preceding 9/11, the diurnal temperature variations across 48 of the stated in the US, had become 2 degrees more
David Travis of the University of Wisconsin-Whitewater and two colleagues measured the difference, over those three contrail-free days, between
the highest daytime temperature and the lowest nighttime temperature across the continental U.S. They compared those data with the average range in
day-night temperatures for the period 1971-2000, again across the contiguous 48 states. Travis's team discovered that from roughly midday September
11 to midday September 14, the days had become warmer and the nights cooler, with the overall range greater by about two degrees Fahrenheit.
So, with this in mind, and the ever increasing reliance on air travel, its easier to imagine that the effects of contrails will always have an effect
on our surrounding environment.
I wasnt going to add this but I thought I would give the chemtrail believers a chance to disprove this theory as its only fair.
Apart from this, what is everyones else opinion? Should we be searching for alternative measures to stop contrails from affecting our climate, or is
this an over exagerating of a seemingly innocent problem?