THEY'RE reportedly responsible for killing bees off in their billions and now it's been claimed Chemtrails could kill off human kind in just a few years, according to shock comments from a US expert. And the "covert operation" could allegedly cause biblical style floods that will pour down toxic chemicals including lead and mercury leaving catastrophic results. US eco expert Michael Tamez says the little trails of clouds that you see left behind by jet aircraft are more sinister than the average human realises. And that it's all to do with "Stratospheric Aerosol Geoengineering" that is being kept secret from the public. Explaining the theory, he says that there's no way the line-like clouds that are left by aircraft are responsible for the long lasting patterns in the skies. He told Express.co.uk: "They're long trails of cirrus clouds that stretch across the horizon and then spread out across the sky. "After about a half hour or so, they begin to appear foggy and disappear into the air