I’ve come across a number of people who are convinced about the chemtrails conspiracy. At first I paid no attention, but after a while I was curious to know why it seemed to appeal to so many. So I looked into it, read some of the arguments, watched a few videos.

• Topic of “Chemtrails” Discussed at United Nations Global Warming Session - YouTube
• Geoengineering Chemtrail Investigation Demanded by Shasta County Residents - YouTube
• Are Commercial Airlines Spraying Chemtrails Over Australia?
• Why the "Chemtrail Conspiracy" Is Real | GreenMedInfo | Blog Entry, which links to:
  • Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health

Briefly, here are my thoughts...

I watched most of the video from the UN. I see that the people have concerns, however I don’t find that their concerns are substantiated with good-quality evidence.

“The trails left by planes don’t look natural” isn’t good evidence; neither is “the appearance of trails left by planes changed in the late 80s”. As an engineer I say that is in the realm of highly-speculative.

“We’ve found contamination in air and water supplies” is of course a concern, but doesn’t prove a particular cause.

The claim that governments are deliberately poisoning populations by high-altitude spraying of chemicals is an implausible plot, because such indiscriminate release would affect their ideological “good guys” just as much as their ideological “undesirables”.

The claim that governments are deliberately poisoning populations by high-altitude spraying of chemicals is technically implausible, because high-altitude release of chemicals seems such an ineffective and wasteful delivery mechanism. As an engineer, I’d expect effective delivery would require low-altitude (200 m or less) spraying of targeted communities, crop-duster style.

The chemtrail claims I’ve seen seem unable to decide whether these chemtrails are about poisoning the population or weather manipulation. That’s presumably because the theory is speculative and not backed by good evidence to specify either scenario.

To substantiate these claims with good evidence, the following would be good:

• Flying a plane or balloon into a chemtrail to sample the chemicals in a chemtrail directly.
• Identify the particular planes, equipment (tanks, pumps and spray nozzles) and chemicals used.
• Find a whisteblower to produce documents showing the who/what/when/where/why of a plot. (anything in the Snowden archives?)

The claim that it’s a widespread worldwide conspiracy seems implausible, because it would be impossible to keep such a secret if it engages an entire global industry, requiring tens of thousands of pilots and maintenance workers to all keep quiet about planes, tanks, spray nozzles and chemical purchases, without a single whistleblower.

As for the Coal-Fly Ash study, it suports the claim “we’ve found contamination in air and water supplies”, providing analysis of rainwater samples to identify a contaminant. But the methodology used and the subsequent interpretations of the data are scientifically atrocious. Analysing local rainwater, and then concluding chemtrails must be real, is indefensible “leaping to a conclusion”. There are numerous other hypotheses that could explain rainwater pollution/contamination, which must be examined before concluding, “it was chemtrails”.