evidence: Washington, DC— Well-understood physical and chemical processes can easily explain the alleged evidence of a secret, large-scale atmospheric spraying program, commonly referred to as "chemtrails" or "covert geoengineering," concludes a new study from Carnegie Science, University of California Irvine, and the nonprofit organization Near Zero. [...] The research team undertook their study in response to the large number of people who claim to believe in a secret spraying program. In a 2011 international survey, nearly 17 percent of respondents said they believed the existence of a secret large-scale atmospheric spraying program to be true or partly true. And in recent years a number of websites have arisen claiming to show evidence of widespread secret chemical spraying, which they say is linked to negative impacts on human health and the environment. [...] "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, which are becoming more abundant as air travel expands. Also, it is possible that climate change is causing contrails to persist for longer periods than they used to." Caldeira said. "I felt it was important to definitively show what real experts in contrails and aerosols think. We might not convince die-hard believers that their beloved secret spraying program is just a paranoid fantasy, but hopefully their friends will accept the facts."