evidence: Surveyed scientists debunk chemtrails conspiracy theory [...] "Despite the persistence of erroneous theories about atmospheric chemical spraying programs, until now there were no peer-reviewed academic studies showing that what some people think are chemtrails are just ordinary contrails," said Carnegie investigator and co-author Ken Caldeira. "Contrails are becoming more abundant as air travel expands. Also, it is possible that climate change is causing contrails to persist for longer than they used to." [...] UCI’s Davis said: "We don’t imagine that we’re going to sway the beliefs of hardcore adherents to the chemtrails conspiracy theory with this study. But we thought it was important to go on the record with fundamental scientific facts to refute claims that the government is deliberately spreading harmful chemicals from aircraft."