Contrails ?....a depressing outlook

While we wait for the increasingly rare event of a clear evening to occur I have found myself pondering the upsurge of obscuration caused by the abundance of contrails in recent years. When I did a search on the web to see if the problem got much of a mention I was amazed at the mass of material relating to it. This page gives a pile of links worth looking at....controversial stuff but still food for thought.
If you prefer something less contentious Wikipedia is informative.
This link is perhaps one of the more relevant for astronomers.