Despite conspiracy theories about so-called chemtrails, there’s no evidence that the white plumes seen trailing from high-flying airplanes are part of a secret government program to spray toxic chemicals into the atmosphere for mass sterilization or mind control.
But contrails do pose a threat, NBC News reports. Scientists say they contribute to climate change by trapping heat that radiates upward from Earth’s surface. A new study published in the journal Atmospheric Chemistry and Physics suggests that the global warming effect will triple by 2050 as air travel grows in popularity and new technology enables planes to reach the higher cruising altitudes where contrails tend to form.
“Given the forecast for the increase in air traffic, which is very large, this contrail effect will increase even more than the carbon dioxide impact,” says study co-author Ulrike Burkhardt, an atmospheric physicist at the German Aerospace Center’s (DLR) Institute of Atmospheric Physics. “And so it will remain the largest aviation impact on the climate,” outpacing the contribution to warming from the carbon dioxide and other greenhouse gases in airplane exhaust.
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The warming effect from contrails already represented the largest contributor to aviation’s climate impact back in 2005, when aviation accounted for 5 percent of the human impact on climate. That’s less than the overall contribution from automobiles and other ground vehicles, but aviation’s impact will likely increase given the growing air traffic.