You might want to take a closer look at the links I posted. Both of those are Government studies. One by Washington State and the other is Federal. Not anonymous at all. Not fake news.Your same government assessment experts were convinced the open air detonation of the first nuke would destroy the earth by igniting the nitrogen in the atmosphere.
Where are you getting your assessments? Anonymous fear-mongering warnings are fake news.
As for your claim that the experts were convinced of atmospheric ignition caused by the first nuclear test, it's ridiculous. My evidence of that is the simple fact they did the test. There was some thought that it was a very small possibility held by some involved, but the risk was so insignificant they did the testing anyway. Also keep in mind that there had never been a nuclear explosion, so everything they were doing was theoretical. EMP is an observed phenomenon that is measurable and predictable.
That pretty much covers the quality of my sources. I notice that you still haven't offered yours.