World Surveillance Group Inc (fka WSGI)

[pokestake]

The higher contrails are ice particles caused when the contrail water droplets freeze. In this way it transforms into a simple high altitude cirrus cloud. They taught me that in high school earth science class many years ago. Some people don't pay attention in school then they have to make up outlandish explanations for what they observe in the world, like in the dark ages.

The lower altitude trails are water vapor, not ice because lower is warmer. These quickly evaporate which is to say that the liquid, condensation droplets return to the vapor state.

It is true that the persistant cirrus clouds caused by contrails increase the earth's albedo and decrease the amount of energy that reaches the earth from the sun, but we don't hear much about that these days because it runs counter to the popular climate change theories of the day.

Like all cirrus clouds, the ice does eventually return to the vapor state, but without passing back through the liquid, condensation phase in a process known as sublimation. More from earth science class.